All language subtitles for [English (auto-generated)] Learn NestJS – Complete Course [DownSub.com]

learn the fundamentals of nestjs by

building the back end of a Spotify clone

nestjs is a framework for building

efficient scalable node.js web

applications you'll learn how to design

a database create rest apis and deploy

the apis to production how did Alie

develop this

course welcome to my course

nestjs let's talk about what is

nestjs nestjs is used to build server

side application in node.js it is built

on the top of node.js

expressjs and

typescript the major difference between

nestjs and other nodejs framework is

this framework is using

typescript and it is using the angular

architecture angular Concepts on the

pack if you familiar with angular

concept you can work with nestjs is very

easily why they are using the angular

concept because if you use the angular

architecture Concept in the back end you

can organize your project in a easy way

the development would be

easy the contribution for other

developers would be easy in

sjs look at the

documentation you will find the

controllers providers modules middleware

exception filter pipes guards inter

interceptors and custom decorators all

of these are Concepts in

angular why they created nests if you

have worked with Express you don't have

any structure like you don't have any

best practice to organize the backend

project so they created the structure

architecture level they designed the

architecture to build server side

applications in nodejs and

typescript under the it is using

expressjs and

typescript so they are just solving the

architecture problem when you build the

large application in nodejs we backend

web application in

nodejs when your code base is increasing

day by day it's hard to follow specific

architecture that's why they have

created the

nestjs if you follow the nests you will

see hey we need a controller we need a

provider we need modules we can break

application into multiple modules we

need a middleware we need exception

filters so this is how you can architect

your backend

application this is exciting project I'm

going to share you all of these Concepts

in this course

let's create a new project in

njs first of all you need to install ljs

globally on your machine I'm going to

install nestjs CLI this this command

will help us to generate nests

project my CLI has installed now we need

to create a new project you can use this

command Nest new the name of the project

you can choose any name

here I just use in fundamentals dpro I'm

going to use

[Music]

npm now it is going to it's going to

install all of these packages for

me now my project has created

successfully so I'm going to navigate to

my project

directory this is end fundamentals Das

Pro now I'm going to open that into my

code editor I'm going to use vs

code so when you open the package.json

file you can run your project in

development mode by using this command

npm start

Dev npm Run

start

D

you can see my project has started

successfully uh by default njs uses 3000

Port you can verify that from the main.

file I'm going to go to the Local Host

call in

3000 let's see what will

happen you can see Hello

World so our project is running fine now

in the app controller you will have a

simple message the simple controller

method it's a route get

hello and you will see the hello world

here hello world or you can say hello

I'm learning

nestjs I saved the application it has

reloaded

successfully let me send the request

again you will see hello I'm learning

njs

so this is our source folder you will

place all of your Source folder source

code inside the source folder this is

our main.ts file when you run this

command npm run Start Da njs is going to

call this bootstrap function and inside

the bootstrap we have a factory function

and we are initializing the app module

this is our root module in here we have

set the port we have the service we have

module controller and the test file for

a controller this is our module remember

this is the angular structure and each

module is consist each module consist of

controllers services and providers you

can import multiple modules here we have

the

[Music]

service and uh you will place all of

your spec file inside the test end to

end test should be uh saved here and

unit testing you unit testing files will

be located here this is eslint RC rules

for eslint prettier

n if you want to customize the nest C

nestjs project you will do inside the

nest CLI we have package.json file we

have TS config and TS config build this

is used for typescript configurations

let's talk about the concept of module

in

njs in njs each module is consist of

providers controllers imports and

exports so this is the building block of

nestjs application you can read my notes

I have provided you the PDF

documentation nest in providers nestjs

are classes that act as a Services

factories or

repositories if you have worked with

angular you know the

providers so you can encapsulate your

business logic and it can be injected

into controller or other

services so controller serve as the

function of handling HTTP request

whenever you create a new endpoint you

will register it inside the

controller I'll teach you more about

controllers in the next video Imports is

an array specify the external modules

needed for the current module you can

import other module let's say you have

break down your application e-commerce

application into multiple modules you

have post module you have products

module you have ERS module you have

users module let's say a user module can

use

the product module this is how you think

in terms of modules if you want to

export you can also export controllers

and services from the current

modules so each nestjs application will

have a root module just like in angular

root module serve as the entry point and

is responsible for instantiating

controllers providers and other core

elements

nextjs follow the module isolation

principle ensuring that application is

organized into distinct functional or

feature based modules so you will have

root module app module let me check the

application you will have the app module

you can see that you have Imports array

this module has app controller and app

service let's say we're going to build a

back end of Spotify application we can

divide our application into multiple

modules you will have a root module and

I'll have the artist which is feature

module and we will have songs module to

handle the songs functionality we have o

module to handle authentication these

three are all the feature

modules SS modules are a functional

organizational unit that follow the

modularization principle it helps to do

code free usability and separation of

concerns principle under the hood they

have implemented the principle design

pattern to organize your code that's it

let's create a new module I'm going to

create a song

module you can use CLI Nest G4 generate

in the name of the module which is the

module keyword I want to generate the SS

module here you can provide any name I'm

I'm interested in the songs module so

you can see in the app. module it has

added the entry automatically for you in

the Imports array and you can see you

have a songs module that's it so this

songs module will have controllers

providers and imports and exports

array controllers are responsible for

handling incoming request and sending

response back to the client we are

building the Spotify clone

application let's imagine or let's say

you want to fetch all the songs or you

want to see all the songs of Martin gck

artist your browser will send the find

all songs request to the nestjs

application inside the nestjs

application you will have songs

controller inside the songs controller

you can see we have find all

method the find all method will be

called and this method will fetch the

songs record from the

database and send respon response back

to the

client similarly you can send the same

request from your mobile application so

controller will be responsible for

handling request and sending response

back to the

client you can create a controller very

easily all you need to do is

controller

decorator and inside The Decorator you

can provide the prefix route prefix

if you want to define the request

Handler inside the controller you have

to use the HTTP get decorator if you

want to create the post endpoint you

have to use the post

decorator it's just returning a simple

string message fetch all the songs and

this method will be converted into this

API

endpoint Local Host callon 3000 /

songs

we are going to build these API

endpoints to fetch all the

songs to fetch a single song I created

these routes to create a new song to

update a song on the based on ID and

delete a song on the based on

[Music]

ID I'm using the rest client extension

to send the API calls it is similar to

The Post

men if you don't have rest client you

can find from the vs code extensions and

find the rest client the rest client

package is saying You must have a file

with

HTTP I created the HTTP

extension now my application is running

at Port 3000 my development project is

running at 30001 you should not aware

you should not care about this project

we are building project on Port

3000 if I send the request to fetch all

the songs we don't have any rout yet it

is giving me the warning message or

error 44 you don't have all these end

points I want you to accept the

challenge and start building these end

points we don't have any

controller let's stop the

application and I'm going to create a

controller

songs you can see that songs controller

has created inside the songs

folder we have spec file testing file

and controller. TS file this is the

controller decorator this is the

prefix one more thing it has added the

end entry in the controllers

array now let's create the request

Handler first of all I'm going to

implement the

get find

all it is going to return a simple

message find all

songs

let's restart or run the

application you can see that our

application is running

now let's fetch all the songs I got find

all the

songs find all songs endpoint it means

we successfully created the route to

fetch all the

songs now now I can send the

request to fetch the songs watch all

songs end

point let's create a

single

song endp

point you have to use the ID as a

dynamic

parameter I can say find

one

here I can

say fetch song on the based on

ID similarly we

need update put for update I'm going to

use the put HTTP

verb

update update song on the based on ID we

also need

delete

I can get the delete from

here let me replace the update to

delete delete song on the based on ID

and finally we need a post

endpoint to create a new

song I can say the

post

create create a new

song so we created the CED API end

points now it's time to send all the

request it's working fine now create a

new song endpoint update song on the

based on ID delete song on the based on

ID

now you got the basic understanding of

controller and how to create route in

njs

application let's talk about Services

services are providers it means you can

inject into another class it will be

treated as a

dependency we will have a

service and the service is responsible

for fetching data from the database and

saving data to the

database if you have to interact with

database you have to write the source

code inside the service you will create

a method to interact with

database we will use repositories don't

worry and this service can be injected

into controllers if you have multiple

controllers into module you can inject

the same service into that controller or

multiple controllers you can also export

the service from a current module and

you can use that service into another

module we will have the song service

it's nothing more it's just a class and

all you need to do is to injectable

decorator it means you can inject as a

dependency into another class

this is how you will inject the service

into controller or into a class you have

to inject it in the Constructor it will

be treated as a dependency for the songs

controller now the songs controller is

dependent on song controller is

dependent on the song

service let's create a new service

I'm going to use n CLI to generate a

service let's write the name which is

songs it will create a class and it will

inject into our songs

module you can see

that we have the song service spec file

which is testing file and we have the

surver

we we have used the injectable

decorator one more

thing it has registered as a provider

inside the songs module I told you

services are provider providers could be

factories helper

function you will learn more about

dependency injection in more details in

the later

mod so I told you service services are

responsible to interact with database

right now we are not going to interact

with database we'll use the postris SQL

postris database in the later videos for

that here I'm going to create a local DB

which it should be array local

array saving saving record in the

disk private read only songs array I'm

going to create the empty array let's

define a new method to create a new song

and it is going to

return

let's push the song make sure you get

the song from the create method there is

a method push and I we need we need to

provide a new

song and let's create another method

find all and and it is going to return a

simple array this. songs and I can

return this. songs

array so we have created two method now

it's time to inject this

service into the controller I want you

to do it accept the challenge and do

it all right I'm going to do it for you

song

service now inside the create I can use

the song service by using the this this

do song service please create a new song

I'm going to provide a dumy

name Animals by

[Music]

Martin you can choose any name don't

worry we will create a separate song

model and separate interface for the

song let's call the

return and for the find all I am going

to use this do song service.

findall let's run the

application

our application is running let's send

the API request to create a new

song you can see I got a new

song if you sent all the songs

request I got all the songs

let's save another

song you can see I got five songs let's

fetch all the songs I got all the

songs so our service is working now in

the real world

application we will write the database

code code here here save the song in the

database and here what we will do fetch

the

songs from the

DB but we will implement this feature in

later

videos in this video I'm going to teach

you how to validate the request

body when you send request to the Local

Host call in 3000 3000 SL song we are

trying to create a new

song but let's say if I miss the title

field it is going to give me the

validation

message the title should not be empty

and title must be

string let me REM know the artist

now you can see title should not be

empty and artist should not be empty so

I would like to add this

validation to our create new song API

endpoint when you go to the

Spotify if I click on any

[Music]

song this is the title of the song and

this is the published date or release

date and this is the duration so we're

going to pick title duration and the

date of the

song let's do

it this time I'm going to use class

validator let's install the class

validator

package and we also need class

Transformer

you can see both packages have

installed nexts provide validation pipe

you can use validation pipe for specific

controller method you can use it here or

you can use it here it's your choice but

but I'm going to create a global I'm

going to register it as a global so I

can use in any

controller so you can call use

method there is a method which is use

Global

pipes nexts already created the

validation

pipe you don't need to create it

again I have imported the validation P

from next sjs common

package and now if you don't have dto

which is data transfer object you have

to specify the network data transfer

object properties let's create a new

song create a new file create song

d. now we need to add decorator paste

very

adds let's create a new

class and I'm going to name it to create

song

dto the first property is title I'm

going to make it read

only and we have the second property

which is artist

array and we have another property which

is release

dat

or you can specify the type which is

string and the type of part is it's an

array and we have the

DAT there is another

property which

is

duration

we need to store the duration in the

time

format now I'm going to use the

decorator from class validator the type

of title should be string and it's a

required property so you can say it's

not an

empty we can follow the same stuff for

artist not empty

it's an

array it's an

array and you can say type

string let's add decoration decorator

for release

date type should be string and

class validator provides a

decorator is date

string now we have for if you want to

store the time or add the validation for

the time there is a there is a decorator

which is military

time and it's also required property so

I'm going to add is not empty

so is date string if you want to apply

that you have to add the date in this

format and you have to add the time in

this

format now we're going to apply we have

already

registered validation pipe here and we

created the data transfer object which

is create song dto now I would like to

apply this create song dto in the create

endpoint

you can register it or you can apply it

by using the body parameter please apply

it on the request

body and I can say create

song create

song dto the type is create song

dto and this time I'm going to push

create

song

dto let's try to test it out and we need

to run the

application so we have to send the

request or add the Json body in the

response let me open the rest c. HTTP

file and we need to add the Chason body

let's send the

request you can see title should not be

empty title must be string artist should

not be empty and artist must be an array

so validations have applied

successfully I can say let's say lasting

lover the

title and we need the

artists

s

let's now we're going to test it

out so we have this

record if you will add the date in

different

format you can see dat should be valid

ISO 860 date string for date string

format if I do in this way you will get

the error dur must be valid

representation of military time which is

hours and minutes so it's working fine

now let's talk about the

middleware a middleware function runs

before executing the route

Handler inside the controller songs

controller I have the find all route

Handler and the create route Handler if

you if you want to run any function

before executing the route Handler you

can write your code inside the

middleware it's a

function a browser wants to fetch the

songs before fetching the songs would

you like to call any method would you

like to run your logic would you like to

execute any type of

code middleware can have request object

response object and next

function it means you can customize the

request object if you want to add header

if you want to log the request time you

can do

that a middleware can execute any type

of

code you can modify the request object

if you want to add the request header

authentication token to the request you

can do in the

middleware you can end the request and

response cycle you can call the next

middleware function by calling the next

method we're going to build the logger

middleware let's

imagine you want to send request from

your browser to

server before executing the route

Handler I would like to log the request

message or the DAT

time let's implement the logger

middleware it's a class we're going to

build a class based

middleware and to create a middleware

you need to implement the nextest

middleware

interface it provides a use method and

use method will have the request

response and the next function

here I'm just logging the request dat

time and at the end I'm also calling the

next

function it will if you will not call

the next function it will not go to the

next

step one more thing middleware it's is

like a

dependency you can inject into module

it will act as a

dependency here we are injecting the

middleware as a

dependency to inject the middleware as a

dependency we need to implement the nest

module interface it will provide the

configure method and the consumer will

be middleware consumer and we just need

to call the apply method from the

consumer

object and you need to provide the

logger

middleware here you need to specify

where do you want to implement the

logger middleware I would like to

implement for songs

API let's implement the locker

middleware before creating a middleware

I'm going to use Nest

CLI please give me the help for nest

generate command

you can see that I got all the commands

related to Nest

generate you can generate class

controller decorator filter

guard middleware pipe

provider we also have other options like

no flat please do not create directory

or no spec please do not create testing

file let's create a new folder

common I'm going to place all my middle

Wares inside the common

directory next generate

Mi common

SL

middleware

and the name of the middleware which is

logger and I don't want a spec

file please do not create the

directory let's try with no flat and

dash dash dry run

let's see what will happen dry run it

will not

create the actual file but got the steps

you will get the understanding how it

will

run it's working fine now no files

return to dis but when you EX cute this

code it will create the logger

middleware file inside the middleware

directory that looks good so I'm going

to remove the dry run let's write the

file

perfect we have created the logger

middleware you can see that it has

already implemented the nest mid

middleware

interface and I got the use method with

these three arguments request response

and the next function here you can

customize the request object if you want

to add your custom logic you can do it

here I can say request dot dot

dot new date whatever you want to do do

to dat

string so we created the

middleware

now I told you or I taught you how to

apply the middleware I want you to do it

in the app

modle we need to implement the nest

module you can see that I got the

configure

method and we need to call consumer.

apply the name of our middleware which

is logger

middleware and we have the four

roots or

routes I can say the

songs now we need to test it out let's

run the

application

my application is running now we need to

send the API

request if you will send the request to

the root URL which is Local Host colum

3000 our middleware function will not

run because we applied the logic to

songs

route fetch all the songs and I

got the the log here request log send

the post request I got the request log

send the put request or send the delete

request I got the

log there are two other options to

implement the or to apply logger

middleware I can say option number

one consumer. apply logger

middleware for

routes

please run for only

songs path

and for only

run request method.

poost it could be option number

two if you send request

get request to fetch all the songs it

will not run if you will send the post

request for the songs I got the request

if you send the put you will not see the

request

log another option we

have let's do

it

consumer zor dot apply logger middleware

for

routes you just need to provide the

controller it could be option number

three it depends on what use case you

like to

use now I can fetch all the songs and I

got the request

log which create a new song I got the

request

log update a new song and I got the

request

log this is how you will create a

middleware did you think about the error

handling in

njs if error comes from your application

code nestjs provide builtin HTTP ex

exception so let's say error comes

while

fetching the data from DB but we did we

did not add any logic to handle the

errors

gracefully let's

imagine we got the error while fetching

the data from the

DB error in

DB while fetching record let's imagine

that when error will happen nestjs will

send this error to http exception this

is the built-in exception in

nestjs let me let me send the request to

fetch all the

songs you will see the server error with

500 status

code next s has sent this message from

HTTP

exception but you can use the

exception in your controller

functions let's say I can

say

or did you think about how can you catch

the

errors you have to use the try catch

block I can log a simple

message I am in

the catch

block and this is my

error

let's try to fetch all the

songs you can see that I got the error

message I'm in the catch block and this

is the

error it means we successfully got

caught the

exception but we want to send the useful

method in the useful status code in the

response I can not see anything

here for that we need to use the HTTP

exception I can say through new HTTP

exception it's a

class and we need to provide the

message can say server error or whatever

you want to say I can say server

error and we have to provide the status

code

HTTP status provides a lot of status

codes you can use

anything whatever you want to do for me

server

error internal server

error if you want to send the message or

cause which should be the error this

one let's try to fetch all the songs

you can see that I got the message

server error with 500 status code which

successfully caught the

exception but if you want to use

different error message you can do that

you can use forbidden status

code it will

work let's restart the

application now I got it

so we have the status code 403 instead

of

500 I'm going to replace forbidden to

internal server

error this is how you will cach the

exception in your source

code if error will come from this

service this this method

TR cach block will cat the

eror got

it let's talk about the pipes in

njs there are two use cases to use the

pipes the first one is to transform the

value here in our example application we

have the find one method

we are expecting the ID as a input

parameter by default it is going to give

me the string so I can use the parse int

pipe to transform the string value to

number here you will see the type of ID

it should be

number another use case for pipes are to

validate the input parameter

in the create method we will accept the

input argument like song title song

artist we will validate the all the

input arguments by using the validation

pipe let's implement this transform

value in our demo application

so I'm going to remove

it let's start it

again it is giving me this

response in nestjs you get you can get

the dynamic parameter by using the ram

decorator Ram decorator and the name of

our argument which is

ID I'm expecting the

ID

and I use the template

string let's define the type of

ID I'm going to send the request you can

see the type of the ID is

string we were expecting the number

type but nestjs got us the string

type you can convert this string into

integer or the number by using the pipe

Pars in pipe that's

it let's send the request to fetch the

song on the based on ID you can see I

got the number ID number type if I

provide the string value

here you will get the validation error

validation failed numeric string is

expected bad request

error if you want to customize the error

message you can instantiate

it eror status codee HTTP status dot not

acceptable now I got not acceptable if I

provide

the numeric string I got the ID which is

number type of the ID is

number we successfully transformed the

string value to number value in the next

video we will implement the input

validation using pipe we will create the

custom validation

pipe you have learned how to inject

dependency by using the Constructor

based dependency injection

pattern we have injected the song

service into the song

controller what what will happen when

songs controller will inject or

instantiate the song service let me open

that songs

controller here we are injecting the

dependency song

service and we have provided as a

dependency

here this one this song

service when Nest container instantiate

the songs controller it first looks for

any dependencies in our case we have the

song

service when it finds the song service

dependency Nest will create the instance

of the song service and cach it and it

will return

it if already created the cache then it

will return from from the cache it will

not create the new

instance let's imagine you are using the

song service inside the multiple

controllers the first controller let's

say we have the songs controller I'm

using it first time

here if I use song service inside the

song service dos back file it would be

treated as a second time now the second

time it will not create any instance it

will get the instance of the song

service from the cache this is the

Singleton pattern applied here next

under the hood created a Singleton

single instance of the song service and

it is going to share the same same

single instance throughout our songs

module but you're going to learn

multiple scope if you want to use the

scop scope strategy if you want to

instantiate a new instance after for

after every incoming request you can use

the scops but I'll talk about the scops

later there are many techniques to use

the providers some of them are standard

providers value Prov providers known

class based provider

tokens class providers we use that class

providers Factory providers used Factory

providers and nonn service providers

we're going to play around with all

these six

techniques let me explain with the help

of

examples this is the standard provider

inside the S module we are using it as a

standard provider but you can convert

the above

syntax into this one let's use

it I need to open my

project we need to create a new

Branch model 3 lesson number

one

open the socks

module so we are using the standard

provider technique but you can write the

above syntax or above

code by using this syntax I can say this

is

provider just this

it

now we have the song service and the

song service please use it as a class

when you inject it into another

class we are using inside the class in

injecting as a

dependency

now you can test the

application

I'm going to send request to any

URL let's create a new song artist must

be

[Music]

stream this is this

true why artist I

think so I got the

issue in the create song d

I did add the H should be true I'm

telling to class

validator the elements of the array type

should be string each element of the

array should be

[Music]

string now it will it will be working

fine if we have three articles or three

artist Martin

and

John you can see that it's working fine

now

so we also tested this syntax this is

the standard

provider but if you like this syntax you

can keep this syntax but I just want to

show

you I'm going to this out uncomment this

one now I got the song

service now I'm going to talk about the

value

providers if you want to create the

moing service instead of the original

service

you can do that with the help of use

value the use value syntax is useful for

injecting a constant value or you want

to put an external Library into Nest

container or replacing a real

implementation with more

object we are using this

one we are replacing a real

implementation of song service with Mo

object

so when you need this use case you have

to use the use value or if you want to

inject a constant value you can use the

use value or if you want to inject

external Library into the nest container

you can use the use

value let's do

[Music]

it

I'm going to create a mocking object

here we have a find all method inside

the song

service when you open the song

service you will see the find all

method but we have to return the songs

I'm not going to throw the

arrow

would be song

service and use

value which is songs moing object Mo

song

service that is it

now

now we need to test

it I'm going to fetch all the

songs and this time you are getting the

response from the mo object not original

song

service so we have the find all method

and it is returning this

one if I will app add the

artist I'm going to fetch all the songs

from the mo service object mock

service and you can see I got the record

from the mock service instead of

original song service find all

method we have learned how to use the

use

value

now if you want to inject the known

class based provider you can do that

let's say I want to inject an object

with

connection we have three

properties connection

string if you would like to inject any

object object as a dependency you can do

it well with use value I told you you

can inject constant by using use value

you can object an you can inject an

object or you can inject the working

object let's create a new file with

connection.

file and I'm going to specify some

connection

properties you have to create an new

constant. file inside the common folder

and I'm going to add the constants

directory here you will have constant.

TS

[Music]

file I can say

connection. and I'm going to copy the

code I just defined three variables and

I have Define the type which is

connection now I would like to register

it as a

provider you can register inside the

songs module or you want to register it

to app module it depends on you provide

this is the name or the token

value this is

how I will

inject in the class when I will inject

in the class I'll use this token

[Music]

key use value let me

provide which is

[Music]

connection so we have to inject it

inside the

song service I can use the add inject

decorator so

songs

controller I think I injected inside the

song

service so I'm going to inject here

inside the song

service or let me inject in the

Constructor

function

here I would like to

inject I can

say

inject let's provide the

key

private

connection here we need to provide the

type I have defined the type this is the

type so I can

log the

connection this.

connection if you will not add the

private so you can add directly without

adding the this keyword I did not add

the provider so I access the connection

string without adding the

this so let's say this is I can

say I'm going to use the template

string this

is connection

[Music]

string when songs controller will be

instantiated this Constructor function

will be called so it will log this

message you can see we have this is the

connection string so I can get the

connection

string now I can see this is connection

string and I can say the connection

[Music]

string or you can

say my SQL dot

dot col do

dot 1 2 3 6 or maybe

Port I created the fake or dummy

connection

stren you have learned how to inject the

object as a

provider and used it as a

dependency

now we're going to talk about class

based provider we have already used the

class based provider here this

one not this one this one used Class so

I'm going to

create a

new

service this this will be called da

config

service inside the dep config service

I'll have one property and a one

function DB host and get DB

host remember it's an injectable

service so you can register it as a

provider inside the app module by using

the use class syntax and you have to

provide the name of your service in our

case we have the da config

service and and then and then I can use

the dev config service inside the app

service

so I can

create a

providers hold up let's

rename

providers let's create a new

class def

config

service.ts

and we

have these properties we have TB host in

the get TB

host so let me register inside the app

module

we have provider and I can say please

provide Dev

config service in the use

class Dev confli

service and and now I can inject inside

the app

module let me inject it

here I can say

private

Dev

config

service and I can say def config

service and I can call the method from

the D config let me convert into the

template

string da config

service. DB

host so

we have to send the request to the root

URL to test

it

rest let me send the

request hello I'm learning NS

fundamental and this is the DB host

which is St config which is Local Host

DB

host

so if you want to inject the known

service provider like a simple

object and you want

to inject Dynamic

value you have added the check or if

condition if node development equals to

development then you you have to inject

the dev config otherwise you have to

inject the pro config if if you have two

objects and you want to inject on the

based on condition this is the known

service provider it means these will not

be

classes if you have this type of use

case you can inject by using the use

Factory so I'm going to

call inside the app module let me let me

show the

demo I just created the two

object and in the

provider we have used the key which is

config and I use the used Factory and we

have to provide the arrow function it's

just returning a value Dev config and

the pro config if you want to in inject

dependency or inject provider only based

on condition then you can use the US

Factory and now the same way you can

inject config

value in the app

service here we have to inject

it by using the

inject decorator provide the key which

is

config in

private

config we have Port value and type a

[Music]

string and you can say Port should

be this do config do

Port so we have to test it to send

request to the root

URL now I got

the host which is Local Host and the

port which is

400 so we have to add

4,000 you have learned how to inject

provider as in the standard way you have

learned the use value you have learned

how to add non class based provider you

have learned how to use use class

provider how to use the dynamic how to

in how to register the dynamic

provider and finally you have learned

how to how to register known service

providers

the previous video you have learned

multiple techniques to register a

providers when you register a provider

by default nestjs use this scope default

it means a single instance will be

created which is called the Singleton

pattern and this single instance of the

provider is is shared across the entire

application nextest cach the instance

when application request for the second

time it will not create a new instance

second time it will return from the

cash another injection scope technique

which is

request a new instance of the provider

is created exclusively for each incoming

request and we have the third technique

injection scope technique transient

providers are not shared across consumer

each consumer that inject a transer

provider will provide a new dedicated

instance most of the time you need

default scope because single turn

instance is recommended to improve the

performance of your

[Music]

application when you get the instance

from the C

it will give you the instance in the

more faster way instead of creating the

complete object it just give you the

copy of the already created

object so you can play around with

injection

Scopes let's

say if you want to use it inside the

song service I didn't I could not find

how to debug the dependency injection

so you have to use

here

[Music]

scope injection

scope what we have to say

scope scope

to

transient the performance of your

application will be

hard it will decrease the performance

but but it depends on your use case what

are your

requirements similarly when every

incoming

request if you have use case you want to

create a new

instance you can use it well for the

requesting purpose for testing

purpose I'm going to open the songs

controller

and here we have to

[Music]

say

it's an

object let's import this

scope I'm going to send the API request

it's working fine

one thing you did not

notice when I will create a new song it

should add the song in the array

so I have created three

objects three songs object in the songs

array when I will send the request to

fetch a single song or all

songs it should give me the empty

response because on every

request it will delete it the complete

data complete

songs

because it will also re instantiate the

song service inside the song service we

we have the

are we have the songs

are you can see I created the song now

when I try to fix all the songs it

should give me the first song or all

songs you can see the empty

response in this video I'm going to

teach you how to add one to many or many

to one relationship between two entities

where a contains multiple instances of B

entity and B entity contains only one

instance of a

entity we have two use

cases we are building this Spotify

clone if you are using or you use

Spotify each user has its own playlist

and each

playlist can have multiple songs so you

as a user can store multiple songs or

save multiple songs in the playlist so

there is a one to one one to many

relationship between playlist entity and

the songs entity see similarly we have

each user can have multiple playlist

many playlist can belong to a single

user so this is also a many to one

relationship between playlist and the

users let's create the playlist entity

and add

relationship we don't have any

playlist entity go ahead and create a

playlist

entity I have created a new folder

playlist. entity. TS

file so I'm going to copy couple of the

code from

my

notes we have created the playlist

entity

now we have to make make a relationship

between songs and the

users

similarly type orm provides one to many

decorator and this represents the target

entity relation entity we are making a

relationship with song entity this

representing the inverse side of the

relation in the song model we have a

playlist

property and we have the array of the

songs I'm going to copy this code and

I'm going to paste it

here we don't have song.

playlist open the song

entity here we can add a

relationship but we also going to add a

relationship between user so I'm going

to copy this code and paste it

here now we have to add many to one

relationship in the song

entity so many songs can belong to a

playlist for each unique

user we have to import the playlist

import many to one

relation and finally we have to add one

to many relation in inside the song

inside the users user

entity so I'm going to copy that

code inside the user

model and I'm going to paste it

here

now everything is fine

now I have added many to one relation in

the song it means it will have the

primary key of the playlist entity and

save it as a reference key or the

foreign

key now we need to create the clip

playlist

module I also want

[Music]

to create a new playlist I'm going to

create a new

endpoint but first of but first we need

to register our new entity I'm saying to

type orm please convert or make relation

between playlist and the user playlist

and the

song

every everything is fine now when you go

to the pg

admin refresh your

tables you will see playlist

table this is the playlist

table and we have the user

ID when you open

playlist entity we have added the many

to one relation it means it will have

the user ID as a foreign key and inside

this song entity we have added many to

one relationship as for the playlist so

this song will have

the primary key as a foreign key of the

playlist entity let me show

you inside these

songs we have a playlist

ID relations have created successfully

we created one to many and many to one

now I want to show you how can you save

a record with relation

entities

go ahead and create a playlist module

you can use with n CLI to create a

playlist module but I'm going to use my

not

notes

playlists

module. and I'm going to paste my

playlist module we don't have playlist

service and we don't have playlist

controller I can create these two files

controller. let's

create playlist

dot

service.

file I'm going to copy

my playlist

service we have to import couple of tip

dependencies inject

dependency and we need

playlist we need a

user

we we need a song that is good right

now also need to get the

injectable we also need to import report

osit

Tre I don't have any user so import the

user we have service right now and we

going to create

controller

or we can

build create playlist

function I'm going to create a new

method you can see that we don't have

create playlist

dto we are just creating the instance of

playlist I'm providing the name of the

playlist when you go to the playlist

entity you have the name

property each playlist can have multiple

songs so I will get IDs of the songs

from the request

body we are using the same logic in the

previous video we

used here I'm setting the relation with

songs

entity I am creating the playlist when

you are when you need to create a

playlist you have to provide the

name and you can set the relation for

the

songs and you can set the

relationship for the

user when we will implement the

authentication I will not find the user

directly from the database I'll get it

from the logged in

user we have set the relationship with

user and finally we are saving the

playlist we don't have create playlist

D go ahead and create a playlist

D we have used that

logic I'm going to create a new file

playlist

dot or you can

say it should be new

folder dto inside the

dto playlist create playlist

dto create

playlist do

D.S we are expecting the name type

should be string and I'm getting the IDS

of the song from the request body that's

why I specified the number type the

array of the numbers and we have the

user it should be a number it should be

the

ID and finally we have to use the create

playlist

dto we have to import

it and now we have to build our

controller function and the

endpoint do we have a controller yes we

have a

controller everything is good to go I've

have specified the playlist with this

endpoint we injected the playlist

service we have used that logic and I'm

returning a simple playlist in the

response we have to register the

playlist module inside the app module

and it will also be treated as a feature

module just like we did with songs

module we have playlist

module now I have to test the

application you can test it by sending

the

request do we have a user I already

created the user in the previous

video I can double check check it my

users you can see that we have three

users I would like to save the record

for the second user with ID number

two rest

client we have to create a new playlist

I can say create new

playlist we have to send the post

request Local Host column 3000 playlists

content type is equals to

Json

application

Json let's provide the

data I'm going to create a new playlist

with Feelgood now I would like to save

the song with ID number six do we have

the song with ID number six let me

double check it

yes we have the song with ID number

six and this is our user let's say I'm

going to say I'm going to create with

user ID number

two it's not a

valid

request

now it looks fine we need to add a space

here we have a playlist feel good now

and we have a one song with ID number

six and we have this user so this user

has playlist feel good now and it has

only one

song you can double check it from the

playlist

this is the playlist

record in this video I'm going to teach

you how to connect nestjs application

with type orm and

post nestjs provide multiple drivers to

connect with database if you want to use

mongod DB you can also do that if you

want to use my

if you want to use post you can do that

in this video I'm going to implement the

post with

nestjs uh typ orm is a object relational

mapper you will write the code in

JavaScript objects and these objects or

classes will be converted into database

tables if you want to write SQL queries

you don't need to write plain SQL cury

you can write queries in the form of

objects

first of all you have to install a

couple of dependencies we need nestjs

typ orm package and post driver and type

orm uh open the package tojson file and

you have to install these dependencies

I'm going to add them

here let me install all of these

dependencies

we also need typing for

nestjs we have to install this

package I'm going to install as a def

dependency we

already have this package types at

node

we installed these packages njs type orm

post and type

orm so now we need to import the type

orm module into our root module in our

case root module is our app

module so we have to call this method

from type or a module and you have to

provide the connection strings or

connection properties like type host

Port username password database entities

and

synchronize whenever you will create a

new entity you have to register it here

for synchronize means whenever I will

run the application please delete the

data from all the all the tables

synchronize please delete everything

from the table but do not use

synchronize in production otherwise you

will lose the production

data whenever you have to create a new

entity you have to add it here inside

the entities array so the for root

method Sports all the configuration

properties exposed by the data source

Constructor from the type or a

package I have installed PG admin if you

don't have you can install the post

admin I'm using PG admin 4 you have to

provide your password let's connect with

server we have to create a new database

right

now I'm going to create a new database

Spotify

clone this is my

user go to the app module

and we have to import the type type or

module

here we have have to install manually

it's not giving me

suggestion

from

Nest JS type

orm and we need to get type omm

module so I'm going to call a method

type orm

module do for root with we have to

provide the

options database which

is Spotify

clone host which should be Local

Host and we need to specify the port for

post gr I think 4

5432 by

default username for me it's postcript

add you have to provide your password

for me I think it's

root I specified the database name and

we have empty entities right now I don't

have any

entity and synchronize set to

true it will create the database

tables

po

it should be usern name not a

user so how can you verify we have

successfully connected to type

orm you can use data source object in

the app

module now you can inject

it and I can

log let's add

private you can log anything

from DB name let's

say and I can get it from the data

source

dot data

source. database

this do I have that property let me

check

it dat source. driver dot

database Let's test it

out I'm getting the

error wrong

driver so I think I did not provide the

type let's add the

type the type of the driver which is

post

now we have made the connection

successfully you can see DB name which

is Spotify

clone you can also

check the songs table inside the Spotify

Let me refresh it and I would like to

look at the

tables we have the

tables I don't have any song because we

did not create any entity right

now but we have successfully

connected to the postris

database in this lesson I'm going to

teach you how to create an entity entity

is a class that maps to database table

or collection when us using

mongodb you can create entity by

defining a new class and Mark it with an

entity

metadata and inside the metadata you can

provide the name of the table in our

case I'm going to provide the songs

table

name an ID which is the primary

generated column the ID will be

generated automatically it's an auto

increment and we have the title I use

the column

decorator for artist array postris also

Sports error data type you have to

provide the column and I'm using the V

character you have to say this column is

an array type you have to specify the

array should be

true and we have a release dat property

or release dat field in the database

table I'm specifying the call colum

decorator and we have and we are seeing

this the type of this field which is

State we also have time type in the

post you can say we have the duration I

specified the date data type in the post

Cas you can Define the time I don't want

to save extra date field here I only

need Time Properties time related

metadata and lyrics lyrics could be the

long text that that's why Post sports

text type if you want a long if you want

to store a string with long content or

long long

length entity songs which is the name of

the

table and you can say I spec I

have I I have specified the description

for each

field

when you will create the entity you also

need to update the lyrics in the create

song datto we did not we did not add

lyrics property in the previous videos

that's why I use the lyrics it's an

optional property it depends on the user

does user want to add lyrics or

not and finally we need to register the

entity to the app module and then you

can can test the

application let's try to implement

it go ahead and create an entity I can

say

songs or song.

entity songs. entity or song whatever

you want to call let me say what I

called song.

entity

dots let's specify the

class I can say

song I can provide the

entity the name of the table which is

songs now we

need primary generated

column ID the type should be

number and we have the title

field let's specify the title

[Music]

column

title type should be

string and we have another column this

time we have the artist

array you have to specify it as a string

array here I I can say the V

character V character and

the type should be

aray and we

have release date duration release

date

let's it should be

date release date type should be

date and we have

duration type should be

time

duration and the

date and finally we have the

lyrics type should be

text

lyrics type should be

string

now we need to test this

entity you have to

add register the entity in the song in

the entities

array now it should create the songs

table for

us let me test it out from the PG

admin refresh the tables I got the songs

table

with these columns

ID title artist release date and the

duration we don't have any

[Music]

record so

let's

update the create song dto and I'm going

to copy

it and I'm going to paste it

here create song dto let's add another

field the optional which is

lyrics everything is fine

now we have tested

it in the next video you are going to

learn how to perform C

operation we're going to fill these

methods update delete find one find all

and the create this time we going to

fetch and save data to the

database let's perform cred operations

type orm Sports repository

pattern for each entity type orm

provides repository and this repository

has CR features like create create

record update record find record and

delete record repository provides the

method first of all you have to register

the type or a module as a feature into

the songs

module

we providing the

entity like these entities I would like

to use inside the songs

module and it it will provide the

repository songs repository here then

you can inject the songs

repository to use songs repository you

need to import the type or a module into

songs module just like we did it here

this this module uses the four feature

method to Define which repositories are

registered in the current scope we only

need song entity that's why we use the

we have imported or added the song

entity now we can inject the songs

repository into the song service just

like we did we did it as a dependency

injection please inject the song's

repository and the type of the entity

which is song and you can in you can

import repository from nestjs type or M

package now I told you songs repository

provides scrud method to create delete

update here you can look at

that create delete fetch records from

the songs

table let's implement this create song

method this time we don't need to add a

record in the local DB you're going to

save the new song by using the song

repository. save

method let's Implement

here in the songs

module we have to

import type orm module as a

feature provide the song entity I would

like to use this entity into the songs

model in songs

module now you you are able to inject

songs repository into the song

service so I want you to inject this

songs

repository Constructor

pattern songs

Repository

repository and I can provide the song

type which is

entity now you have the exess of crud

methods so song repository provides this

safe method just like you learned here

it provides this safe method for first

of

all we have to create a new

song and it should

return a

promise with

song so I just

created should say

create song

dto the type should be

create Song

D so I just created the instance from a

song class I specified the title I got

the title from D I got the artist from

dto duration lyrics and release date

from the dto and finally you can

call Safe method this. songs

repository and I will would like to call

this safe method and provide a newly

created song and it should return the

object get rid of the songs array I

don't want to use

it we also need to remove everything

from

here now it's time to test this G

method make sure you have

called

yeah it should use the up

expression

here

in the controller let's look

at

issue here it

should promise and the

song inject the

repository inject

repository and we we have to provide the

entity which is

song so everything is fine you can test

without a sync V by default it should

return the

promise

HTTP let's create a new

song we also need

lyrics

I'm going to send the

request

amazing we have a song you can verify

from the

database you can see that that I got the

first record this is the lyrics duration

and the release

date now it's time to implement find

all it's easy to implement the find all

all you need to

do is provide the return type

promise with song

array return this do songs

repository do find that's all you

[Music]

need

and in the

controller songs

controller

you can also add

promise with song

aray

let's fetch all the songs from the DB I

got the array right now we have only one

record now we need to implement the find

one find by ID you can create a new

method inside the song

service and it is taking the ID as a

parameter and returning the promise with

song you can

use song repository. point1

method and in the

controller we need we need to pass the

ID as a integer

and return the

song in the

response let me open the songs

controller we already did

it I'm getting the

ID all you need to

do is return

this. song.

find1 here I can

say promise with

song Let's test it out by sending the

request only the based on ID you can see

I got the first record if I try to fetch

the second record I don't have any

record that's why I got the

empty let's implement the remove

method I'm going to create a new method

inside the song

service it's just returning

nothing

or you can say delete

result you can use

that and

return

here and we need

to use this method into the songs

control

ER we have to call

it this Do song service.

remot and we have to provide the

ID we did not pass the ID or get the ID

as a

Prem I'm going to use Prem

decorator and get it here

ID

and it's returning

promise with delayed

result we need to test it out first of

all let's create a new

song

to we have a

song lasting lever

two the ID of the song which is two now

you can perform the delete operation I

would like to delete this

record so I got the delete result we

have successfully

deleted if I try to fetch all the

songs

[Music]

no I think I deleted with ID number one

so first record has

deleted and we need to use the

update let's perform the update

record so we

need update method I'm going to create a

new

method inside the song service we don't

have update DTU data transfer object you

need a tip you need a new data transfer

object for update the

record because when you update the

record all the fields are optional but I

can get update result from type

orm we don't have update song dto we

have to create it

I'm going to create in the

dto update

song Das

d. so this time we have to copy

everything all the fields are optional

all I did I copied the create Song D and

put the optional for every title for

every

field

is title should be optional so I can say

instead of empty it should be

optional it should also cre it

here is

optional is

optional now it looks good

so we have to use the updates s

video now we need to implement the

controller

function songs.

controller that we need to get the Prem

and we need to get the

body need to get the pram and update

song dto and I'm going to call this do

song service.

update the first one is ID and the

second argument is update song

tto you have to import

it the return type should be promise

with update result that's

it I have found the

issue which is this space content

type let's try to send the update

request duration must be valid

presentation now it looks good so you

can double check it from the

database this is the record with

id2 we have successfully

updated the

record we have tested the

application in the next next lesson you

will learn how how to implement the

pagination now we're going to implement

the

pagination I'm going to use external

package to implement pagination in

nestjs uh first of all you have to

install this

package

I'm going to register it

here and we have to install

it and now I'm going to add a new method

inside the song service this time I'm

going to call it

paginate and I'll use paginate

method from nestjs type or M paginate

and it will accept the pagination

options like page metadata when you will

fetch the record on the pation it should

give me the items array and we have this

metadata total items item count items

per page total pages and current page

these are all the options

inside the options object and finally it

will return the pation and we have to

provide our model which is

song and we have to call the page unit

with song

entity we have to provide the songs

repository and the options if you need

to add a cury builder like filtering or

sorting you can also do

that but here is our control rer

function we use the Prem now we're going

to use security decorator and it should

name of the field which is Page you can

add a by default default value which is

one and I applied the pars int and I

have added the default

value

and we have another field or another

property and I'm getting it from the

cury prams this is the limit and default

limit which is 10 and I applyed the pars

into pipe operator and finally it should

return the pagination with song entity

if limit is greater than 100 please do

it 100 otherwise we have to specify the

limit or tell or add the

limit there is a page unit method we

created inside the song service and you

have to provide the page and the limit

we're getting the page and limit from

the

cury so you have to test it by sending

the cury parameter page which is two and

the limit whiches to I want to see two

records per

page and I want to see the page number

two if you want to add the Sorting you

can also do that by using the query

Builder

please apply sorting on release date I

want to see the latest song on the based

on date let's implement it or you can

Implement by your

own first step we have to

create a new method

paginate and we need these

options I can import all of these from

the

method so we have the pagate

method now we have to call it inside the

songs

controller you can it depends on your

use case but I I'm going to call the

paginate method in the find

all so I'm going to replace my find all

method to this find

all we also need cury

Prem

it's just getting the es lint warning

messages we also need

default value

pipe we need pagination from

nestjs that looks good

we can test

it this time I'm going to send the

request to fetch all the

songs it has applied the limit 10 and

default value which is page which is one

over the first

page total items item count items per

page 10 and total Pages we have one and

current page which is one let's add

another

record new song

to let's add another record new song

3 let's add another record new song four

now we have four

songs

you can

say I want to see the page number one

this

time I want to set the limit to two I

want to see only two records per

page we have the items array you can see

we have only two

records there are total two pages we are

on the first page and items per page two

item count two total items we have the

four I told you if you want to add

sorting you can also do

that by using the query

Builder inside the song

service I'm going to add curil fer

here and we have to provide cury Builder

not songs repository we have to fix

it cury

Builder let's provide the cury

Builder

please

create a new song

with let's say a new Five song latest

date it should should give this record

first let's create it created a new

song I got a latest song Only the based

on release date it means it's working

fine

now in this video I'm going to teach you

how to build one toone relationship

between two

models one to one relation where a

entity contains only one instance of B

and B contains only one instance of a

let's take an example a user can become

an artist or an artist can have only

single user profile so there is a one

toone relationship between user and the

artist we don't have an artist model or

artist

entity first of all you got to create

artist entity with primary

key and then you have to create the user

entity because we're going to make one

to one relationship between artist and

the

user I'm going to have ID field or First

Column first name column last name

column email column and the password

column for user

entity now we're going to add one to one

relationship type or provides one to one

decorator to add relationship between

two two

entities uh in the first argument you

specify the relation type I'm telling

type orm I would like to make a

relationship with with user

enti this is the type of the relation

you specify the relation entity type by

following this syntax AR

function and this join column will rep

will

create the reference key or a foreign

key of the user entity inside the artist

entity so we have so we will have a user

ID as a foreign key inside the

artist and finally you have to register

the user and artist entity in the app

module now we're going to implement

these

steps let's create the first a new

Branch

so I'm going to create a new artist

entity if you like you can use CLI

command to generate a new entity so I'm

going to say artist do

entity. file I'm going to copy my

code there is nothing here you already

learned how to create an

entity and next we have to create a user

model a user entity go ahead and create

a new folder with

user or

users let's keep it to

artist so I'm going to create a new

entity user.

entity. P the code we have ID field

first name last name email and the

password and now we're going to make a

one to one relationship I would like to

store the user ID inside the artist

model if you want to store artist ID

inside the user you can also do that it

depends on your use

case like I want to make a relationship

here let me do it

here we

need one to one

decorator

specify the type of relationship by

following the syntax we would like to

make a relationship with

user and here we will have the user and

the user and I also need a join

column that's it for

now cannot find a module user. .ts

file so we have to import it

manually now it looks

good and now we have to register these

entities inside the app module we

created couple of new

entities please convert these entities

into tables I can say

artist and we have

user our last step is to test the

application and I have to run my PG

admin let me connect with post this

database

so it has successfully let me check my

schema which is 45

clone I have to connect

it inside the tables we have the artist

and the users

table we have have the user ID inside

the

artist and inside the

users we have for columns or ID first

name last name email and the

password our application is running fine

now this is how you will make one toone

relationship between two

entities now we're going to talk about

how to implement many to many

relationship

ship many to many relationship is a

relation where a contains multiple

instances of B entity and B entity

contains multiple instances of

a let's take an example many artists can

publish many songs and multiple artist

can belong to one song or multiple

artist can publish multiple

songs we have a multiple many to many

relationship inside the artist nestjs or

type orm provides many to many

decorator this will specify the target

relation

entity and this is the inverse side of

the

relationship and it will have the songs

array and on the song we will have the

artist array we have a many to many

decorator the target entity in the song

we have Target entity which is

artist and the second argument

specify the inverse side of the

relationship inside the artist we have

songs property that's why I can access

the artist. songs and inside the

artist entity we have song. artist

that's why I can access the artist from

this song entity song. artist that is

the inverse side of the relation when

you set the casc to

true it means you can create or update

the record while creating a new song or

an artist I'll teach you the benefits of

ask

getting when you implement the many to

many relationship you you need a joint

table many to many imple uh relationship

always work with third table which

should be joint table and I rename it to

songs artist and this songs artist will

have primary key of the song and the

primary key of the Artist as a foreign

key

and we also need to refactor some create

song dto instead of using EST string EST

string we going to we are going to get

IDs from the request parameter IDs of

the artist and IDs of the artist in the

update song video and then you have to

register the artist entity in the songs

module that's because I want to the

artist repository inside the songs

modle and finally you need to refactor

the create method we're going to get

artist here the first

step we are going to get this artist IDs

from the request object or request

parameter or the request

body and then we will find all the

artist only based on IDs and finally

here we are going to set the song do

artist equals to artist if you have set

the casket to true just like we have

done it done it here cascading we set to

true now it will set the relationship

between songs and the artist it will

automatically create the record with

third table which is the joint table

here here it will create a record it

create records in the songs artist table

by by setting the relation with this one

songs. song do artist should be artist

and finally we're going to save the song

in the using song

repository and you can test the

application now um let's implement it

first so we have many to many

relationship I'm going to add this

relationship in inser the

artist I'm going to do it

here this specify the target relation

type and we don't have we we did not

create the song. artist inside the song

entity now we have the songs array let's

import many to many

I'm also going to implement it

here many to many

decorator the target entity in our case

it's an

artist and it's going to take the

artist let's specify the inverse side of

the relation artist dot

songs and we will have join

table I'm going to name it

to songs artist or artist song let's

take it the songs

artist and finally I'm going to specify

the artist

array

duplicate

identify yeah I don't need this type

because I'm not getting the string array

from the artist instead of I'm getting

the array of the artist from the request

parameter

we added many to many relationship

inside the song model or song

entity and we forgot to set the

cascading to

True here you can do it inside

here G SC to

true

now we need to refactor the create song

dto I have to

refactor

from it should be

number and the

first argument is an

empty and and it looks

good similarly we have to refactor the

update song

dtoo it should be number array of

numbers the first argument is

empty looks good now we need to register

the artist entity inside the songs

module so we can access the artist

repository inside the song service

I I'm saying to type orm I would like to

access the artist repository inside the

songs module or the song

service that's why I have to register it

here and finally we need to refactor

create

song I can say create uh inside the song

service so you can do it too if you want

here we have

to find all the

artists on The based on

ID then we have to set the

relation with artist and

songs so you can do it but first of all

we have to

inject the Repository which is

artist I can say

private artist

repository and

repository I can say

artist let's get all the artist

you have to add a Sync

here this do song artist

repository find by IDs I can use that

method provide the artist ID from the

song

dto

artist now I can set the relation

with song. artist it should be artist so

we have set the cascading it will create

a relation many to many relation with

songs and the

artist now it's time to test our

application rest

client here we have to send the post

instead of artist we need to send the

IDS of the artist

a user can become the artist so we don't

have any record in the artist and the

user model you have to create it

manually so I'm going to

refresh you can see we have the third

table which is songs

artsts is

not artist we have to fix

it

inside

this inside the

songs

entity here we have to fix

it

this

I'm going to refresh the

table get it off this table you can drop

it delete or drop yes now we have song

artist with song ID as a foreign key of

the song

model artist

ID we don't have any user right now I

want you to create it manually let me do

that

I'm going to add a new record with ID

one it should be

Jane or

saga

Saga

gmail.com I'm going to add anything here

pass password let's add another

user I can say

Jane and I can say

do Jan at

gmail.com password 1 2 3 4

5 now you can save the record so we have

two users right now

if you want you can also add another

user or artist I can say

Martin

gar

Martin at

gmail.com 1 2 3 4

5 let me save the record so these two

users are the artists but we need to

make a relation inside the

artist

table let's add a new record with ID and

here we have to add a artist

ID let me double check

it yes one and the three

one we have to add

another artist one the ID should be

three so these two are the

artist ID should be here we have to set

the ID should be

two now it looks

good so what I'm saying

that a user with ID3 is an artist a user

with ID one is also an

artist so one Martin and seag are an

artist and Jane is a just a simple

user so when you create a new record I

can

say let's add a

new song so these two are all the artist

they are going to create they have

created a new song

I can say you for

me that is it right now I'm going to

send the

request sounds good we have a new record

title this is the artist

ID this is the complete

artist so we have an art ID

one and we

have the relationship

let me double check it from the artist

and the

songs it just created a single record it

did not get the ID 1 and three I don't

know what is wrong with

it

let's do it here one and three you for

me

to again I am getting the ID only

one let's log

the song

d.

artist 1 and three then what

why 1 and three it looks

good maybe the issue

with

here

console.log

so when you look at the artist

record oh we have one and the

two so one and the two instead of 1 and

three

let's provide the

two you and for me

three

now I got the artist ID one and the

two it will also addit a relationship

here inside the songs and the artist I'm

going to

find now you can see

that a song ID with 10 has two

artist these two

users user ID number three and user ID

number

one in this video you're going to learn

how to implement this signup

functionality a user can create an

account in our application and we need

to save the user in the

database first of all we have to install

dependencies I'm going to use bcrypt JS

password bcrypt JS package to save the

user

password in encrypted format I don't

want to save the password in plain text

like 1 2 3 4 5 we have to save the

password in encrypted format that's why

you have to install this

dependencies let me open my package.json

file I'm going to add a new entry let me

copy

it and I'm going to paste paste it

here we also needed to install the

typing for

typescript I have to add the typing in

the dep

dependency I'm going to put it

here so I'm going to run npm install

please install dependencies for

me you can see two packages have

installed added new two

packages now we have to create a user

module and the Au module we don't have a

user module and Au module inside our

application I'm going to use nest

CLI to generate a new module I can say

o we have created a new o

module you can see

that we also need to generate the ser

service for

art you can see that Au service has

generated we also need

controller I can say

AU

an au controller has created it has also

added the entry inside the controller's

part we have it has automatically

imported Au module inside my app

module here is the O module

now we have to

create the users module one more thing

we did not export the odd service

yet here I I can say I would like to

export the Au

service it means whenever you will

import the Au module into another module

like we have imported the Au module into

app module it means

I can inject the OD service inside the

app

module that is why I exported the OD

service let's create the user

module I'm going to create

manually

users. module.

TS I paste

it we don't have user service

yet

we have to create the user

service let's use the

nli a user service has

created we have to import the users

module inside the app

module

so we have the user service and we have

the user

module I've also added the type or a

module and registered the user entity

because I would like to use the users

repository inside my users module I

would like to inject the user users

repository into the user

service now we have to register a new

route inside the O

controller we're going to register the

signup and the login route inside the O

controller we don't have a user dto yet

but we do not we also don't have a user

service do create

method I want you to create the user D

you

first I can say I would like to add my

DS inside the dto

folder

create user. dto

file I'm going to paste my code we are

expecting the first name last name email

and the

password from Network

request this is the network data request

object now we got to create the create

function inside the user service it is

saving the user inside the database

do we have a user

entity now we got to do

it inside the user

service here we have to add the

logic we need to inject the user

repository I've already told you how can

you do

it

I have created the create

method what this create method is doing

remember we have installed bcrypt JS

package let's import it

first

I don't want to copy the code inside the

Constructor

function now it looks

good we have to import it first create

BPT

package here we are just injecting the

user

repository we are generating Assa it is

nothing more it's just a

number we need a salt to encrypt the

user password there is a hash method

inside the bcrypt library and we are

using this hash

method it is going to return the promise

first you first argument would be PL

text password we are getting the plain

text password from the network request

and this is our salt and finally we are

just saving the user depository user

inside the

repository and we are deleting the

password it's an extra remove

them I don't want to send the user

password in the response that's why I

have deleted deleted the user password

and finally we are returning the user

from the response in the in the

response we have called the user

service. create method here now it's

time to test the application one more

thing we have to refactor a little bit

our users

entity I'm going to make it to

Unique should be true because because

email should be unique for each

user and I don't want to save the pass I

I don't want to send the

password in the in the

response it is saying that when working

with type orm there might be cases where

you want to exclude one or multiple

columns field from being

selected that's why we have used the

exlode

now let's run our

application and we have to save the

user we're going to send this

request

HTTP we have to send request to this

route because we created this odd /up

route

we have to provide first name last name

email and the password now we're going

to test it

out I have caught the

error if user service is a

provider

if user service is a provider it is is

it the part of au

module you should learn from the error

inside the Au

module we have to import the user module

because I am using the user service

inside my o

controller or inside the a

service let say user

module here we are injecting the user

service inside the O

controller everything is good to go

right

now we have to test our

application what I would like to send

the signup

request let's create a

new

account I got the error 500 internal

error duplicate key value

Violet unique

key do we have a

user inside our database can say John

one

two still we are getting the same value

same

error cury

failed error duplicate Cube value viate

constraint we have changed a data entity

and the table we have

to we have changed the database Act I

have added two new entries unique

constraint and the

exclude so we need to drop our

schema and let me do

it I cannot

drop we did not use

migrations at the end of this module

I'll show you how to use the migration

whenever you need to update a database

you have to create a new

migration what I want to

[Music]

do I want to disconnect from the

database Spotify

clone now I would like to

delete it is used by some

other let's use

another database I can say

one

I found this is the shortcut to handle

this error because we did not use

migration so I can say that now I got

the data from

scratch where application is running

fine now

let's sign

up you can see that it has resolved the

issue the issue was with database update

I got a

user when you go to the Spotify clone

one get rid of this

one Spotify clone

one and we have to go to the

tables inside the

users

we have a de

cord email john1 12@gmail.com and this

is the password in encrypted

format in this lesson you are going to

learn how to perform login request when

user sent the login request we have to

verify the user from our database we

have to decrypt the user password and

compare the user password we're going to

implement Json web token

authentication a user provides the

credential like username and password to

the

server then our server will generate the

Json web token and send back to the user

it will have the header payload and

signature don't worry I'll teach you

everything when client reive the Json

web

token if you are building front-end web

application you can save the Json web

token in the local

storage when user want to receive or

user wants to receive protected rout he

must need to provide JWT token in the

request

header and server will receive the JWT

to token from the request

header and it will verify or validate

the token if token validated

successfully it will allow you to access

the protected route you will learn how

we are going to implement Json web token

authentication we're going to use

passport passport

strategy or passwort package you have to

install these two

packages I'm going to install it in my

dependencies we have to run npm let

me hold on we did not create a separate

Branch module number

six lesson number two

[Music]

now we have

it npm

install we have installed two

packages the next step we have to create

a login

route I can create inside my o

controller let's create a new login

route we don't have a login D yet we

also don't have a login function inside

the OD service

yet let's create a login

function inside the OD

service au. service here we have to

create the log

function and we

also need to get user service as a

dependency let's create a new

method first of all we are trying to

find the

user on the based on

email if user found it should give me

this

user let's complete this step first we

have to find the

user we did not create the find one

method I can say that inside the user

service let's create a find one

method it is going to take the partial

as a user

and we're getting the email or we can

let's try to use the login

dto login

dto if it did not find the user it

should return the unauthorized access we

have to find the user only based on

email we don't have login dto let's

create a login

dto inside the AU

dtos I can create

login. D.S

file so we have the login

dto I got the

email we also need to import login

dto we also need to import user

entity and it should return the user

that's

it now the second step is we have to

compare the user

password inside the OD service the

second step we have to compare the user

password I have to import the

bcrypt import Star as bcrypt from bcrypt

now I can compare the password with

plain text password and user encrypted

password if password

matched then we have to return the

user and delete the user password if

password did not match we have to send

unauthorized

exception that is it right

now

we did not inject private Au

service now I have called the

dto login method and provided the login

dto

let's try to send the login

request rest

client.

HTTP we have created a user with John

12 John 12 run the

application

let's send the API request to login

user it should be 3,000 not a 3,000

one we successfully got the user back in

the response let's say I'm going to

provide the invalid email I got error

cannot find user if I provide the

invalid

password I got password did not match

and unauthorized it's working fine

now but our goal is to send the Json web

token when user made successfully login

request it should send the Json web

token in the response in the next lesson

I'll teach you how to create Json web

token and how to send the Json web token

in the

response we have found the user on the

based on email and we have encrypted the

user

password if user has logged in

successfully we need to send the Json

web

token and when you will apply

authentication on protected

route you have to send the Json web

token in the

header we're going to use nestjs JWT

package and passport JWT

package and then we will import Port jwd

module you have to provide a unique

key you have learned how to create the

login function and

we you have to refactor it right now you

have to send the access

token you can create Json web token by

using JWT

service this is the provider you can

inject it here as a service provider

then I will move my constants into a

separate file au. constants

does and you have to register the JWT

module and update o constant Secrets I

also updated the expiry date of Json web

token it will be expired after 1

day we going to have JWT service we are

extending it from the passport

strategy remember I'm using the nestjs

passport

package and we have passport jwd

strategy here it is just extracting the

token from the

header we are checking the Json web

token expiry

date or expiry validation or expire

duration here you have to provide your

secret key which we have

saved and then finally we're going to

have validate method it is returning the

user ID and the

email when you apply the

oard oard JWT oard will call this

validate

function you have to register the JWT as

a provider then this is how you will

Implement authentication you got to

create a guard it's like a middleware in

expressjs if you want to implement role

based authentication you need

guards we have jwd odard it is extending

oard from the

passport if you want to add your own

custom logic you can do it

here this is how you will make your

route

protected by using the gwd O card and

finally you have to apply you have to

send the authentication request like

first of all you got a

login login route will give you the Json

web

token then you can access your protected

route like this is the protected route

profile is the protected route

only authenticated user can access this

profile route so you have to provide the

validation token which is this one Json

web token in the authorization barrier

it's a

scheme and it will allow you to access

the

route so let's implement it first first

of all we have to install a couple of

dependencies

here passport

JWT nestjs JWT and passport JWT strategy

I also need dep dependency which is

typing of

typescript let's do it

here and we have to install the

dependencies

these packages have

installed now you are able to use JWT

module let's use inside the app

module we have to register

it we will move this constant into

separate file but right now I'm going to

do it in this

way JWT module. register and this is the

secret

key and finally we have to refactor our

OD

service

if everything is

fine then we can use Au or JWT

service you have to add this return type

return

type

if password mashed generate adjacent web

token or create a pad

object I'm going to create a payload

object now we are just adding email

and the user ID inside the payload and

it is generating the Json web

token let's create a separate file for

the

constants can say o/c

constants

do let me refactor it

here

one more thing you got to register the

JWT module in the Au module instead

of app module that was a

mistake so this is our authentication

[Music]

module we have to register it

here out constants do

Secret and you have to

provide sign in

options

options we have expiry date which is one

day so we have registered the jwd

module now you have to create jwd

strategy I can

say JWT

strategy dos it's nothing more it's a

service or provider you can inject

it

injectable export class JWT

strategy passport strategy it is going

to provide the

strategy passport

JWT

now we have to call Super

Constructor and you can

extract the

header from Au header as a barrier

token and we have to provide the ignore

expiration check the expiry

date secret which is our secret key

ke and we will have the validate

function whenever you apply at the O

card this validate method will be

called

our next step is to register GWT

strategy in the O

module I have to register it here JWT

strategy now you have to create the

guard which is

JWT guard

dos

export class JWT

guard it is also a class or service

provider that's why I I'm using the

injectable and we have to extend it from

the

passport from the odard which is from

the the njs passport

package make sure you say this is the

JWT if you want to extend this JWT guard

you can do

this our final step is to apply the O

card to the public public route let's

say I want to protect this route I did

not create it

yet let's say get

profile and it is going to take

request return request.

user

should be

decorator now we have

to let's do it without

card npm Run start

f

our application is running now let's

send the login request you will receive

the access

token I'm going to copy

it and I going to paste it

here access

token now let's access the

profile

slash profile because we created the

profile route in app

controller I'm going to send the request

cannot access the

profile

I do not add the

route I can access the profile route I

got the 200 status

code it means route is working fine if I

apply the authentication

guard I can say use roles

or use

roles use guards

yep I can mention my guard which is or

guard if you have what in Express JS

it's nothing more it's like a

middleware this oard function will run

before executing the get profile

function this function runs before

request Handler which is get

profile oh it should be jwd o guard jwd

guard not and this not this one o

card

let's rename it to JWT o guard not a JWT

guard JWT oard it looks

good

let's try to access the profile

route status 401 which means you did not

provide the access token please provide

the access token if you want to access

this private route so you can provide

the exess token by using this format I

pasted the

token awesome I got the user ID and the

email I have applied the OD card and

this JWT

strategy method will be called first

they are going to run the Constructor

and then they are going to use the

validate

function in this lesson I'm going to

teach you how to implement role-based

authentication what is role-based

authentication if your application has

multiple roles like artist manager user

accountant CFO person you can have a

different functionalities for each role

in Spotify clone when you look at the

Spotify clone only artist can upload a

song If you are a user like let me show

you you with the help of

Spotify

web.

Spotify

like if I go to my

profile I don't have any feature to

upload a

song Only approved artic can upload the

song or delete the

song in this way you can divide your

application into multiple

roles we have create songs

endpoint I would like to restrict this

endpoint for other users only artists

should access this create song

endpoint we don't have artist module we

have to create artist module then we're

going to implement the artist module

into import the artist module into app

module we have to write a method find

artist on the B on user ID then we got

to add a logic here inside the login

method we will save the artist ID in the

payload object and then you have to

create a new payload

type and finally you need JWT artist

card we will have a separate card for

artist we are extending the jw2 remember

I told you if you want to customize or

add a logic in the guard you can do that

it's just returning a super

Constructor and here we are using the

handle request method this function will

check if you have art artist if you are

an artist then it is going to return the

user otherwise it will throw the

exception we have to refactor the

validate method in GWT strategy we need

an artist

ID then here you will have to apply JWT

artist guard on the create song

endpoint you can do that as well or you

can follow me let me implement

it

let's create the artist

module here we have the artist module it

has already imported into my app

module this one the artist

module we also need R service

next generate service and I can say

artist you have to import type orm

artist

entity module. for feature because I

would like to use

repository here artist repository we

have to provide the Artist as an

entity so we have the artist

service and we also need artist

controller

artist I can use a nest generate

controller

artist

now we have the artist

controller now we're going to create the

find artist

method I'm going to copy my

code inside the artist

service let's do it

here we need to import couple of

dependencies

we have to find the artist on the based

on user

ID our next step is to refactor the

login

method inside the art

service we have to add R

service

injected we need to add a artist

ID inside the payload type inside the

payload if password

matched find if user is an

artist then we need to add the artist ID

into the

payload what I can

say because course I can save the artist

ID in the payload

object user do p. artist

ID should be it is saying that you don't

have artist ID in the

payload you can create a payload type

inside the types p.

type

I can say types.

yes now I can access it I can Define the

P

type it should be user

ID we have mentioned the artist ID is an

optional

property now we need to have JWT oard I

told you how can you implement it we

already implemented the O

card let's say I'm going to create a new

guard inside the

O I can say

artist JWT

godts export class

artist JWT

guard extends o guard

JWT it's a Pur it's a service that's why

I have to use the injectable it's a

service

provider

if I will write the can

activate you can see that I got the code

all I need to call the super

Constructor super do can activate and

provide the

context yep everything is fine you also

have handle

request now you can write your logic

here if there is an error or there is a

no user then you have to throw the

unauthorized

[Music]

exception if everything is good to go

you have

to return the

user if there is an artist ID then we

should return the

user get rid of the extra arguments I'm

not using

them when you apply the artist JWT card

it should call the handle request and it

will extract the user and try to check

the artist ID from the

user if you want to log the user you can

also do that I will show you what will

happen inside the user

we created the JWT AR

card JWT o

card jwd arst

card then we have to refactor a little

bit validate method in the JWT

strategy we can add the

artist it should be P

type

now it looks good we have the user ID p.

email and p. artist

ID and

finally we have to apply the jwd artist

card on your protected endpoint in our

case we have the songs create endpoint

we have to protect it for other

users all you need to apply JWT artist

card

and inside the songs

controller I can restrict this endpoint

from other

users I can say that

jwd artist JWT

C

if you want to log in the request you

can do

that let's try to do it

here request decorator and

request

I think it should be

request it's not a requ request this

one

request nexts commment and then we have

to access the

request why it's giving me the

error

I have to do it

here and

request now it looks

good I can log request.

user

let's start the

application I got the

error the O JWT

strategy JWT strategy what I did wrong

oops forgot to

add I forgot to add closing

parenthesis

if you go to the artist table you will

not see any record because we don't have

any artist record it's an

empty if you go to the

users how many users we

have I have only single user now I would

like to make the

artist what I can say what is wrong

is au module is a valid njs

module Artist Artist

service I think we have to

import the artist module here inside

the are we

using

the rst

service yes we are using the RT

service that is why I need to

import the artist

module and inside the artist

module I can say I have to export artist

service I want to teach you how to

handle errors you must know you must

familiar with error

handling

our application is running

now first of

all we have to create a new

artist I can say let's sign up a new

user or I can say that sign up artist

let's say

that it should be let's say c

Martin

Garrick Martin

Garrick we have registered a user which

which should be which could be an artist

so if you want to make this user Martin

Garrick to artist you have to update it

manually but I did not create the

endpoint but you can do that I taught

you how to do

it let's first of all the ID is

to I'm going to open all the

artist and we have to add the

entry this is user number two and

finally you have to save

it now Martin is an artist

so I have to log in as in Martin

gar I can say sign up artist

or login

artist get rid of first name and the

last name let's send the login

request it should be

[Music]

login I got the

token

now if you check the

profile it should have the artist ID you

can see that this is the artist

ID this is the user

ID this is the artist ID from the artist

table this

one so it's working fine now when you

have to

create I for I got I I have to get the

token

again let's save the

[Music]

token the token will be deleted after

one day I can say that arst token

temporary if I try to create create a

new song it should give me the

unauthorized because you are not an

artist and you did not provide the

authorization

token

authorization b e a

r a r e

r now I can say we have artist which is

one Mart Martin Garrick has an animal

song let's say they want to publish this

song

I have the

artist now it's working fine this is the

user ID email and the artist ID user ID

email and the artist ID so we got this

one artist and the ID colon

one

we have successfully created the

endpoint I can say request.

user

let's create a new song from Martin

Garrick say love

again so this is the request. user user

ID email and the artist

ID in this lesson I'm going to teach you

how to use or how to enable how to

create two Factor

authentication you're going to learn how

to implement two Factor

authentication if you don't know about

two Factor authentication you can read

this text a user enters the username and

password on a login page page after

successful initi initial

authentication the system sends you the

onetime password or onetime

token for the verification a user may

provide the onetime code generated by

the authenticator

app and send to the system then system

validate this token if token has

validated then you are able to

authenticate then you are able to access

the route

we're going to use third party package

to implement two Factor authentication

Speak Easy and we need a typing first of

all I would like to show you the demo

how two Factor authentication works I

already implemented in my development

project I can show you the demo first of

all you got to log to the user I got the

access token we're going to create a new

endpoint to enable the

authentication this endpoint will enable

the authentication for the user and it

will create a secret key let me show you

I'm going to provide this text I

provided the

token now I got this secret key and I

got this response from the Speak Easy

package base 32 I saved this base 32

string to my database table for the user

is for the user

table a user has this

record now I I I got this secret key if

you have authenticator app Google

Authenticator you

can you can place the secret

key I have enabled the Google Chrome

extension I want you to do it when you

look at Chrome Google Authenticator you

have to enable this

extension now I

got this authenticator if you have

Google Authenticator on your phone or

you can install it all you need to do is

to add a new app you can also generate

the QR

code with this OTP path Ot Ot paath OTP

o URL you can generate QR Code by using

this this

URL but you can add manual entry for T

testing Sam profile this is the same

user the name of the user this is the

secret key now I started getting a

unique onetime

password so I have to copy this

password let me do it again it's going

to be removed after 1 minute I copied

it it's going to be

removed yep now I have to provide this

token to validate the user I have Pro

I'm going to provide it here we also

need to have updated token so copy this

one

and

I have to validate the

[Music]

token yes we have to add a new token

because it will be

expired now you can see you are

verified the token has

validated now this user has enabled the

two Factor

authentication if you send the login

request

you see this message hey you have

enabled two Factor

authentication you can implement this

Logic on your front end application

please send the token at this URL please

send the onetime password token from

your Google Authenticator app on the

front end side you can send request to

this endpoint and provide the token

that's a complete flow of two Factor

Authentication

let's start implementing two Factor

authentication we have to install couple

of

packages we need a Speak Easy

package we will use this package to

generate secret key or validate the

token onetime password we also need

typing add it as a def

dependency let's run npm install

packages have installed the first step

you have to add two new columns inside

the user

entity do

entity I'm going to add them here by

default two factor string should be null

and it's a Boolean property by default I

have set to default to

false two Factor secret could be empty

and this is the Boolean

value when you run the

application it should create two new

columns for the user property for the

user

table

our application is running

now let's refresh the user

table I have the 2 FAA secret and enable

2 FAA which is a Boolean

column now we're going to create a new

method inside the O service to enable

the two Factor

authentication first of all we need

maybe we need a

type I can add my type here enable to F

type or you can create an interface

we have to type and then we need a

method you have to create a new method

to find the user on the based on user

ID if user has already enabled to factor

authentication we have to return the

secret key if user did not enable the 2

FAA

authentication then we have to generate

the secret key this is we use the secret

key and we're going to use the base 32

secret key and finally we have to update

the 2fa secret 2fa key for the specific

user and then you have to write the do

you have to return the secret key in the

response we got to find the user if user

already enabled the secret two Factor

authentication we have to return the

saved to to f secret otherwise we have

to generate a new secret and then you

have to set this secret for the user

user and finally you have to update the

user I'm going to copy the

code let's do

[Music]

everything inside the OD

service

I have to create a new

method import Speak

Easy we also need to import Toof enable

type we don't have a method find by ID

do we have a

method find by ID inside the user

service

not we have to create the find by ID

method

you can also do the secret key or unable

to factor authentication here use user

dot let me first add a new method inside

the user

service let's go to our next

step user

service here we need this

method I'm going to copy this method now

we have

defin by ID

it is going to accept the

ID so we have to provide the user

ID you can

enable two Factor

Authentication to

true and finally you can call user. Save

method or no we need a

repository to save

it we also need another method it will

update the secret key and enable the

authentication you can create a new

method

inside the user

service let me import the update

results we have completed the enable to

factor

authentication now it's time to test

it let's create an O endpoint inside the

O

controller

I I'm going to use the guard JWT o

guard if you if you don't

need anybody you can create it as a get

end

point I can say that JW the O

card

[Music]

I just imported missing

Imports

we have a login user sign up user sign

up artist login user here I can

say

enable two Factor

authentication

profile

Au enable two Factor

authentication let me double check that

enable to fa we also need to provide the

authorization token so we need to get

get the

token I got the the access

token provide it

here let's send the request I got the

secret key that's

amazing what is the name of the user

which is

John if you have Google Authenticator on

your phone you can install it manually

I'm going to add a new

profiles which is John

user add your secret

key it is generating onetime password

for 1 minute

only we have also saved the key into the

user users

table let's fetch all the US

[Music]

users here we have the secret key and it

has enabled two Factor

authentication our next step is to

validate the onetime password

token let me open

it we have created a new user or

registered a new user in the Google

authenticator it is generating onetime

password we have to take this token or

onetime password and try to validate

with our

application we're going to implement

this logic first of all you may you may

need another

endpoint validate to fa we are also

using a JWT o card we are getting the

request here we will have a method

validated to f a token it is going to

provide the user ID the logged in user

ID and we also need to get the token

valid validate token dto we will create

validate token

dto I'm going to create a new

endpoint inside the O

controller I created the post because we

need to get the token you can also use

the get and get the token

prams JWT

oard let's create the validate token

dto inside the

dto I can

have validate

token.

D.S

now we have

to create a new method to validate to fa

token here we need to create this method

it is going to accept the user ID the

token the onetime password like this

one this one this

one and we will find the user on the

based on

ID and then we have

to get this secret key which we saved

earlier and then you have to provide the

token and we have to mention encoding

which is based

32 if token is

verified where is

that if token is verified then we have

to return verified to True otherwise we

have to return verified to false you can

also rapar code inside the TR catch

block I'm going to copy my complete

code and I'm going to paste it here

inside the OD

service

the code is complete

self-explanatory now we have to test it

we already created the

route inside the rest

client

I can use

that and I'm going to paste it

here I can say

validate to a

token validate to

fa let me double check my controller

validate to

fa it's a post end point

point and we have to app content

type application

Json let's provide the

token let me get the

token John

user amazing we got got the verifi to

true if I provide the invalid

token I got the verifi to

false I got the verified false

because because token has expired there

is a new

token we successfully enabled two Factor

authentication validated with

token you can

add you can also add disabled

authentication logic or you can have

this

feature let's implement it by creating a

new function inside the OD

service it's nothing more just disable

the authentication and or set this

value we need to have that function

inside the user service because we have

repository inside the user

service I can say

that so we have this method disabled to

fa now it's time to create a new route

to disable the

authentication inside the O

controller I'm going to create a new

Endo

here

JWT o

there is a typo here spelling issue for

the O

guard J WD o

guard

e

everything is fixed

now

let's try to send disable authentication

request inside the Au controller this is

the get

endpoint I can have

that let me paste it here

disable authentication disable to

fa it should be disable not an enable

so it has disabled authentication you

can double check it by

login I got the

token and let me check it from my

DB you can see that it has dis enable

false set the

false

one more thing you can do if you

disabled the authentication you can

delete the secret key or you can use the

existing secret key let me let me do

it yeah we have to disable or deleted

the

key

inside the

disable validate

token

disabled I can

say to FS secret to set to

false

or you can set the null

value let's try to do the null

value let's enable the authentication I

got the

secret double check it from the DB we

have enabled and we have a different

secret

key I don't want to save the I don't

want to change the secret

key you should not change the secret

key maybe it depends on your use

case if client disabl

this to fa maybe he has to scan the QR

code

again let's disable it it looks

good we have empty to fa and it has set

to

false

I also have to add this property into my

notes

if user has enabled to factor

authentication we have to customize a

little bit Logic for the login

method we have to send the

link to user this one validate to F

token this

one if user has enabled to fa and have

the secret

key then you have to return this

type go to the

login or

service go to the login

method here I can add a

logic we have to add return type new

return type

this

[Music]

one let's try to access the login

function by sending the login

request we have enable two Factor

authentication it should give you the

link not an access

token we have to log in the

user where is the login

user here we

[Music]

have

let's double check

it we have empty2 FAA that's why I got

the access

token let's enable

it we enabled the two Factor

authentication let's send the

login

now I got the link validate to fa please

send the one onetime password or token

from your Google Authenticator app you

can implement this Logic on the front

end on front end you can send the

request to this URL and you have to

provide the token a user user has to

provide the

token so we have completed the two

Factor

Authentication

in this lesson you're going to learn how

to implement API key

authentication each user will have its

own API Keys when he wants to access

authenticated route or protected route

he has to provide the API

Keys when you need to control the number

of calls made to your API you can check

from your API Keys how many times API

Keys has

hit if you want to identify the usage

patterns in your API traffic you can do

with the help of API

Keys API key authentication is typically

used in scenarios where multiple users

or application need to access an

API you can read this text you can read

the complete

flow we're going to use this step we're

going to generate API Keys we can create

and store API key for each user we have

to create an API key

strategy strategy service just like we

did for the JWT

strategy and we have to register API key

strategy in a

module and the step number five validate

the user by API key and apply API key

authentication on protected route I have

to use external package which is uu ID

to generate API

key and we will have API key column in

the user

entity and then when we have to create a

new

user what you have to do you got to set

the API key which is U ID by calling

this method it will generate a unique

key when you send the when you create a

new account it should give you this API

key and Next Step you have to create API

key

strategy when you provide the API key it

is going to call this method the

validate function and inside the

validate you have to call validate user

by API key and you have to provide your

API

key if user is validated this is how you

will provide the API key authorization

barrier this is my API key we're going

to use external package passport HTTP

barrier to apply this strategy to

validate API Keys finally you have to

register as a provider API key strategy

this is our method to validate the user

on the based on API

key if user validated with the help of

API

key this is our Endo here I'm I can say

I want to access the

profile on the based on API key or you

can create in the O controller use guard

o guard you have to provide the

barrier it means I want to apply API key

valid ation or API key authentication on

this

route and I don't want to set the send

the user back password back in the

response that's why I deleted the user

password and you can send the message

authenticated with API key this is the

user this is how you will provide the

API key when you make the authenticated

request I want you to implement this

complete flow if you stuck you can

follow my

video Let's install the package

first

let's run the

application you will get the error

because we have two to three records in

users table but it will find null value

for API key we did not set the

constraint API key should be null if

user has signed up we can have the API

key or if if you set the null Lael to

true you can have a separate function to

create the API key for the user it

depends on your use case your company or

your business

logic I'm expecting the null value error

from the type

orm we are using this

database

we have all the

[Music]

users you can see I got the eror

relation user contains null value which

is API

key you can fix two or three

ways you can set API key value manually

but I don't have API key

column there is a concept we didn't use

the

migration but I found the hack to use to

resolve this

issue I can say Spotify clone 2 let's

change the database

Run start

there it will take some time to create

all the

tables database does not exist let's

create a

DB

restart the

application the application is running

fine

now

[Music]

we have this database Spotify clone

2

so we have the API

key now we need to add the API key when

you create a new

account I can do it inside the

user service or odd

service do we have the sign up function

[Music]

here I think inside the

users yes we have the create

[Music]

function

I have to change a little bit logic I

did not create a new user so I'm going

to do it

here we have to import this

package we are getting the

user.

password delete this

one we got it we got the API

key yeah I can say saved

password

I have updated user D to user password

and we have saved the

password and we have deleted the saved

password now we can we have to test it

by sending this sign up request

open the r

client I'm going to send the request

sign up request sign up

user so it has generated the API key it

looks

good we have encrypted password it's

fine

now our next step is to create API key

[Music]

strategy we have to install this

package I'm going to copy the same code

and create a new file API key strategy

inside the

O API Das

key

Dash

strategy. DS strategy.

DS going to copy the

code

we are using the passport strategy and

we are providing this passport HTTP

barrier OD

strategy we have to import or

provide API key strategy inside the O

module register it API key

strategy and we have to validate the

user on the based on API

key I can create a new

method I also need to find user on the

based on API key let's add a new method

inside the user

service now it looks good let's create a

new controller

function into the O

controller it means I'm telling to a or

nests application I would like to

validate this route on the based

on API

Key njs

password everything is good to go right

now we have to test the application

run the

[Music]

application first of all we have to

create a new

account I change the email John 13 we

got the API

key I'm going to store the API

key key John

13

now we have to provide this API key to

access the profile

route access

profile we have a get end

point get

http or/

profile authorization

basic here we have to provide the API

[Music]

key it's not a basic we are using this

[Music]

scheme barrier

scheme b e a r e

r now I got the user back in the

response and it has authenticated with

API

key in this lesson I'm going to teach

you how to debug nestjs application

using VSS

code if you don't have launch. Json file

in vs code folder you can create

it let's create the launch. jsn file if

you go to the

debug I'm going to create a new folder

vs

code and you can have launch. Json file

let me copy these

configurations so I have to start the

application in debug mode nestjs has a

script in package Chon

file now you can start the application

by running npm start Run start

debug you can see that our debugger has

started now I want you

to attach a process when you go to the

debug now you have to attach

it you can put break points let me

to here the O

[Music]

controller I'm going to put

breakpoint let's try to send the API

request it has stopped at this break

point so I can see what is inside the

request

I have request

body request

client request. user you can also watch

on a specific property the request.

user you can see that I got the API key

email enable to fa to fa secret this is

a great way to debug the application you

can find errors very easily by using

debugging if you want to debug the

complete flow you can do that into the

app

strategy what I was API API key strategy

or API

strategy yep we have the API key

strategy I'm going to put break point

here let me put the break point here and

I would like to put the break point here

let's send the request you you can see

that it has first called this validate

method it is going to find the user on

the based on API key it has found the

user now it is going to return execute

this line return

user it

has now it has added the request. user

you have returned API user from the API

key strategy like this one

nestjs has

stored user inside the request object

like request.

user like this

one and finally we have deleted it you

can step over

it go to the next line

if you need to step into a specific

function you have to use this one step

in if you want to go out from this

function you can press step

out in this lesson I'm going to teach

you the concept of

migration migrations is like a Version

Control for your database

you can manage your database

changes by using migrations migration is

a file that contains a set of

instructions for creating modifying or

deleting database

tables whenever you make changes in your

entity you have to create a new

migration if you want to go back to the

previous changes there is a command for

revert you can use that

command once you get into the

production right now we are building our

application in development environment

when we push the application into

production you will set the synchronize

to

false so you have to

manually update the changes to for your

entities that's why I have set the

synchronized to

false in production you will not set the

synchronized property to

True migration is just a file with SQL

queries to update database and apply new

changes to an existing

database I got the simple definition of

migration it's called it's like a

Version Control for your database you

will keep keep track of your changes

toward your

schema first of all you have to move

type orm configuration into a separate

file these are all my type type orm

configurations now you don't need to

write your entities

manually when you have to create a new

entity you add a new entry for the

entity now you don't need

that I have added the regular expression

for this path we also using the

JavaScript because we're going to use

migration I found it's easier to work

with JavaScript when you are working

with with

migrations when you build the project

nestjs will generate the disc

folder this disc folder I can provide

that path this is the JS

file we're going to provide this type of

file I have set this synchronized to

false

we have created a new data

source when you write the script to

migrate in package or Json file you have

to provide the data source file this

this data source and this data source

has a data source object this data

source

object step number

two you have to refactor type or M

config into app module you got to

provide data source options this dat

data source

options and then you have to write the

script for type or M generate run and

revert we're going to use all these

scripts we will add a new column in the

user

entity and then we will run run the

generate the migration based on this

column this is the name of the migration

at user phone where we have St about the

migration here we have specified the

path there is a DB folder and inside the

DB we have migrations

directory and finally you will run the

migration when after creating the file

you have to run the migration if you

want you can implement this complete

steps or you can follow

me

I'm going to create a new file inside

the DB create a new folder inside the

root

directory

DB data

source. TS I'm going to paste this

code my database is which is Spotify

clone Spotify clone

2

so I have to delete

everything here we have to

provide a data source

options this options

object I have completed this step number

two now we need to add couple of scripts

there is no logic logic here

specifically you can copy the

scripts first of all please build the

project generate the JavaScript files

then and then we are using the type orm

npx and

dashd I'm telling to type orm I have

stored my database configuration inside

this

file if if you have to go back or revert

the changes you will run this

command I'm going to copy this script

and paste it here inside the

scripts now let's try to add a new

column user.

entity I'm going to add a new column

here

here type A

String now finally we have to run the

migrations npm run migration generate

I'm using this script here you are

specifying I have I want to store

migration in this file migrations and

this is the name of the file it will

also add the

timestamp first it is going to build the

project then it is going to execute this

command meanwhile I have to start it

from the scratch I don't want existing

database so I would like to delete

Del my

database I'm also going to delete this

one because we have set this

synchronized to false we have to add

changes manually that's why we are using

migrations and new file has created

inside the DB inside the

migrations we have this file this is a

Tim stamp and the name of the file add

user

phone. so we have to create a new

database I can say Spotify

clone now I want to

add all this stuff

like inside the data source Spotify

clone let's generate the migrations I

can say

that my migrations you can choose any

name or in

it

it is going to take all these entities

and creating creating the SQL

files SQL queries for all these entities

because right now our database is

empty

in we don't have

tables

now you can see my

migrations if you check the database you

will not see any table because we did

not run the migration yet now we going

to run the

migration npm run

migration

run now it is going to execute these

queries

these creating all the tables and all

the

relationships we have the

migrations

there is no record inside the

migrations I'm going to

delete this

migrations and this migration file

let's create it from

scratch

it has created all the migration now we

have to run

it everything is good right

now it has executed the queries and now

if I refresh my tables you will see all

the tables we have songs users but if I

go to the

users I will have font property I don't

want font

property let's edit a user entity I'm

going to remove

phone now let's generate the

migration I can say removed phone

you can see that it has created the

migration file removed phone it is going

to drop this

column now we need to run this

migration to update changes in the

database

let's try to check the

column there is no phone column here

this is how the migrations

work this lesson I'm going to teach you

the concept of data

seeding data seting is a process of

populating a database with an initial

set of

data when you create a new

column inside

here

when you create a new column in the user

entity let's say I would like to add a

new

column and here I can say this is this

could be the phone

number

but when you run the

migrations the phone number will be

empty in the

database so you can load your initial

data by running the

seeds applying CED data to database

refers to the process of inserting

initial data into the database usually

when the database is first created let

me show you the demo of

cing

you are going to learn how to create the

seed service and we have a seed method

inside the seed

service we

are

running type orm queries by using

transaction here we have placed all my C

data when my application bootstrap

loads it will create a new user a fake

user and it will save into the database

and then it will create the artist and

save artist into the user into the

database we also have a c data for

playlist first of all we're going to

create a new user then we're going to

create a new playlist and we have

assigned a relation between playlist and

the user so we're going to save couple

of

data when you run the application when

application will be completed

you can verify from your

database let me show

you in your users table you will see a

new user will be created so these are

all the

users these are all the users I created

with fake data by using the

seaing I also have a

playlist it is going to pick the random

name for a

playlist Rap

playlist World playlist or country

playlist I've also have a seed for

artist you can see that now my

application is is running

now when you look at the

users you will see another users couple

of another

users if you look at the playlist you

will find one more

playlist you can also look at the

artist you will have more artist this is

how you can increase your development

workflow or testing

workflow now I want you to implement it

by looking at the documentation I

created for

you

here I don't want a new

column first of all we have to

install another package to generate the

fake

data and next step we have to create a

seeds folder inside the

DB

seeds I can data seed. TS

file I have created a new file while

here we're going

to do initial

seaing you can create a separate

function for each entity like you can

create a separate function for seed

songs I did not create this seed songs

method here you can create

that if you want to look up more

documentation of of Faker package you

can find from your from the official

documentation

page it is giving me the

error entities Source

playlist here I can find the

entity

now our next step is to create a new

seed

module I'm going to use type orm to

create a new seed

module and

then what we are doing here we are

generating the encrypted password I use

the same password for each user here we

are creating the user I got uu ID from

API key and I got repository from the

manager we will call the seed data in

main.ts

file seed module has

created we also need a seed service what

I can do I'm going to copy this

code and create a new service inside the

seed

module see do

service if you want you can use CLI to

generate service we also have to import

or register as a

provider seed

service cannot find um oh it should be

SE data seat should

be I can say this seat data seat

data and it should be gone

we are making connection with our

database here I got the manager from the

quy manager and I called this C data and

finally we are we have started the

transaction if transaction if any query

has failed it is going to roll back the

transaction

so our final step you can read this text

if you want to learn more about what is

cury Runner what is

transaction here you have to boot you

have to call the seed method here

whenever you want to save a data in the

database if you don't want to save a new

fake data you can just disable these two

lines but let me show you the demo I'm

going to start the

application it is going to run these

methods seed user it is going to create

a new fake user seed artist and Seed

playlist let me show you the current

look of my

schema I'm using spotify clone on

database Let me refresh my

tables uh I would like to see all the

users there is nothing here I don't have

any

user you can create many users if you

want you can use fake

package to generate 20 15 50 55 records

and you can and then you can provide

into the repository user repository it

will create all these records but I use

a single record I just want to show you

the process you can manipulate with your

own use

case one more thing I could not find the

official package or official

documentation or in typ orm seeding I

got I have implemented my own

strategy now my application is

running you can see I have couple of new

users you can see I have couple of new

artist I think I will have only single

artist yes but if you look at the

users it has picked a random first name

random random last name random last name

and the email and the password and the

API key it has generated one more thing

if you want to look at the playlist I

will also have a one

playlist electronic music

song that's how the seeding work

works whenever you create a new entity I

would recommend you to create a seed

function whenever you run the

application it is it is going to create

a new data but I'm going to comment this

code you can

enable

the

seaing

here if you want to make it more Super

productive you can create a console

command in

njs I'll teach you in the advanced

Concept in this lesson I'm going to

teach you the concept of

configurations we're going to create

custom configur ation file with the help

of nestjs

config if you see our main. file I have

mentioned the port number

manually if you want to have a separate

port for development project or for

production environment you can specify

in the environment variable we don't

have any EnV file in if you have worked

with

nodejs you will have separate EnV

environment file. EnV file for

development and you you will have

separate. EnV file for

production one more thing if you look at

our type orm

configurations here we have type orm

configurations I have specified a

username

manually password manually database

manually I also specify the host

manually what if you want a different

environment variables for production

let's say you want to deply the project

to AWS or Hoku you need a separate en

andv environment variables for

production level but we did not

Implement that logic now we need to do

it if want to read what is configuration

you can read this complete text I have

explained

configurations you may need a database

setting for in for development and

production you may have different API

keys for production and API keys for

development you can have multiple

environment files for production

production and testing

nestjs provide provide config module

we're going to use this package I'm

going to copy

it and I'm going to paste in my

dependency section or if you want to

install manually you can do that I have

to do npm

install in The Next Step you have to

import config module in the app module

this config module will have config

service and we're going to use the

config service to access the environment

variables let me show you how can we do

it package has

installed now we need to import config

module into the app

module geted of these extra

dependencies

we have to import it here let's import

config

module so here we have config

[Music]

module after importing config module you

have to provide the path of your EnV

file here you have to provide the

path we don't have any EnV file go to

your root directory and create two files

the first one for env.

development for production

level I can say en EnV for

production this one is for development

and this one is for

production if you want to have a

separate port for different environment

you can do that but I'm going to keep

with

3,000 for production you can place it

here so we have created the EnV file so

how can you load this EnV file we have

to set the path in the app

module here I have to provide the

options configurations I can say EnV

file path it can access the array the

first one is do env.

development and do

EnV do

production one more thing I would like

to mention we have used the config

module inside the config module config

module is using do EnV

package if you Google the

envv this package is used to define

environment variables for different

environments for development and per for

production but by default nestjs config

package is using the

EnV we have used this load ENB

property so what you have to make it

Global let's say I would like to import

EnV module into my Au module into the

artist module let's say I want to use

API keys from env. development file to

artist module you don't need to import

config module you can use config service

automatically but if you use if you make

a

global when you want to use config

module in other modules you will need to

import it as it standard with any Nest

module or you can make it Global I have

set it to Global

so I can use config service without

importing the config

module now we have to create the custom

configuration

file you have to create a new folder

inside the source folder I can say

config let's create the

configurations here you have to place

all your

configuration you have to define

configuration inside the EnV

file and this configuration dots file is

is going to fetch or add

validations for environment variables

inside the

configuration so config module is going

to use this configuration .s file it is

going to to extract all these values

from config does let me show you

how we have to load our configuration

file custom configuration file I can say

load you can have multiple configuration

file you can have different

configuration file for database you can

have different configuration file for

app settings or user profile settings

something like that but I'm going to

keep it simple let's use a simple

configuration

file we have to import the

configuration now our next

step is to test the EnV

variable we have created the port and we

have defined or getting the port

from uhv and here now let's say if you

want to access this port variable I'm

going to do it for testing purpose don't

do it in

production inside the O service let's

say I can define a new Vari new function

get EnV

variable you can call any function

here here how can you use

the configuration dots file while how

can you get the this

port into your a

service like we have to inject the

config service we have to inject the con

config

service config

service remember I did not import the

config module into the Au module because

we have set it to Global in the app

module so we can use config

service config service.

get pass it into as a integer you have

to provide the name of your key which is

Port when you open the configuration. ES

file we have specified the key which is

Port so how can you use this function

let's say I'm going to create

a controller function for testing don't

do it in production I just want to show

you the demo I can say

test get

EnV or you can say

test EnV

variable it is going to return this do

out

service calling the get EnV variable

that's it do not do any fancy stuff here

let's start the application and we have

to test this

route now we need to test

it I have to send the request to this

URL this

endpoint we have to send the get

request can say test

EnV 3000 sl/ test

amazing I got the Port Port value which

is 3,000 it's working fine

now now if you check the main.ts

file we have defined the port into

configuration we are using the port

value manually I would like to use the

config service here I want to get the

Value Port value from the config service

and I would like to use it here this is

how you can do it you can get the config

service instance from the by calling the

app.get method and providing the

instance providing the config service

class it is going to give me the

instance config service

then I can use the method

here so you can do it

here config service you can import

it now I

can get the port

value service.

getet let's pass it as a

number here I can say the port which is

key get rid off this no I'm not using

seed service we

have our application is running fine now

let's send the test test request test I

got the port 3000 we successfully

configured the port in the main.ts

file now we also need to add our secret

key inside the EnV

file we are using getting the value from

the Au constants but I don't want to get

it from the Au constants I would like to

add secret key inside my EnV file

I have to place it here secret now I

would like to use this

secret we are using this secret inser

the app

module inser the Au module not app

module here we are using the O constant.

secret but I want to get it from the

config

service I want you to think about it how

can you add or how can you get the value

from config

service we also need to add a property

in the

configuration I'm going to do it

here and this is

how you will get the

value from config service we have to

register this module as a

async and and it is going to return the

dynamic

module so you have to follow this

pattern if you want to configure Dynamic

module Dynamic module is a feature that

allows you to dynamically configure and

register modules at runtime based on

Dynamic

conditions so we have this Dynamic

value so what I want you also have to

inject the config service you have to

import the config module this use

Factory is used to inject the config

service and we are getting the value

here so I'm going to copy

that I'm going to replace my Au module

with this

code import config service and config

module Imports I don't want to use the O

constant get rid of the

Hat we have to import config

module we also need to import config

service that is it

now we have specified The Secret inside

the

configuration did I Define the secret in

the production I think I did

not if you want you can do it

env.

production let's restart the

server our application is running

successfully it means we successfully

configured the secret key you can test

it by sending the API

request I have to open it

here rest

client I can send this signup

request

it's oh I got I sent the login request

we have to send the signup request user

has created successfully

it's working fine now now our next step

is to configure the DB configurations

database

configuration I'm going to add the

configurations inside the my EnV file

development

file if you want to add a

separate EnV file separate configuration

for database you can do it can say that

DB

configuration my database is end

test now we have to define the values

inside the configuration. ES

file I'm going to copy the same code

or I need these

values now we have to update or refactor

the manual

values with configuration config

service so I I'm going to

create a new type orm async config

object and then we're going to use

inside our type orm

module let's refactor it you have to

create it this is the same process you

have to create this module or register

this module as a

dynamic I'm going to use the same

configuration when defining the type or

a

module I'm going to do it

here you can import type orm config

options we also need to get config

module and config

service

type or module

options I got the DB host DB Port

username DB name password entities and

synchronize set to

false here we are going to get it from

the process.env

I'm going to copy

that code and I'm going to paste or you

can

say replace this text

host inside the app module we have to

register

it type orm module this

time type

orm ASN

config get rid of data

source

wrong driver I think something is

[Music]

missing

postgress

we have to use the for root async in the

app module I think that is why it is

showing me the

error

you can see that application is running

fine now it means we have successfully

configured the

database we have successfully configured

the

settings it's working fine

now in the previous video we have

created the environment variables

we have set up the DB configuration DB

Port username password and database

name we if you want to add the

validation if you want to validate these

environment variables you can also do

that with the help of class validator

package to implement the validation you

have to create the env. env. validation.

TS

file we did not add node EnV inside the

development or production.

EnV I have set the Isam which

is

enum here I have defined the validation

for Port DB host username password DB

name and the

secret we're going to use class based

validator class validator package that's

why I created the

class and we will have the validate

method it is going to accept the config

object with record key value

pair first of all we're going to use

plane to instance from class Transformer

package plain instance converts a plain

literal object to class based

Constructor object you can learn more

about class Transformer by looking at

the doc so class Transformer allows you

to transform plain object to some

instance of a class you can look at the

documentation of class Transformer if

you want to learn more about

it

and you have to enable this property to

true and we have to provide the

environment variable which we have

created the class this one environment

variables and we have the config SE

config

object you I'll teach you I'll show you

what is inside the validated

config now it should be the instance of

a

class

if error comes you can send the error

back

otherwise you have to return the

validated config and then you have to

provide this validate method inside the

config

module we don't have node EnV you can

create inside the environment variable

let me do that

first

env. environment I'm going to copy

that in the production I'm going to copy

here now you have to create a new

file inside the root

directory env. validation. TS file

file we will have the enum for

development

environment it could be development

production test and

provision now you have to create a

class to validate the environment

variables we have Port dbhost username

password and the secret now we have to

implement the logic for validate

function it should return the validated

object validated

config so I got the instance of the

class we provided the environment

variables here let's say if I would like

to

log the config I can say please log the

config and here I would like to

say

please log validated

config now we have to perform the

validation

there is a validate sync method you can

use

it let me import

them I'm going to import them

here

if error comes we need to throw the

error otherwise we need to return the

validated object validated config

object so we created the validate

function now it's time to register it

inside the app

module I'm going to register it in the

config module here there is a

validate we have to import the

validate you have to import it manually

it's not giving me the

suggestions can say

validate

from

it should not be

EnV it should

[Music]

be env. validation that's why I'm not

getting the

suggestion because this is a typescript

file it's not an environment

file now I should get the suggestion for

validate

let me import it from env. validation do

not import it from the class validator

package I would like to test this

application you can see that we have I

have the config object inside the the

config object I have the property Port

secret node EnV DB host we Define these

properties inside the environment file.

env. development I got the DB name all

these couple of things now you have

environment variable which is the

instance of a Class A Class based

object in environment variables I got

all this port all this

stuff I'm going to comment this

out what if I set the wrong value in the

development file let's let me test

it if I set the DB Port should be string

let's say

that it should give me the

error I have to restart the application

because I have made changes in theb do

development

file I did not set the validation for DB

Port that's why I did not get the

error let's say I'm going to do it here

DB

Port I can say the type should be

number I have saved the

application I have to restart

it

you can see that I got the

error property DB Port has filed the

following constraints is

number let's replace the DB

Port we have successfully implemented

the validations for environment

variables in this lesson I'm going to

teach you how to increase the speed of

module reloading what do I mean by

module hot reloading if I change

anything here in any file it will take

too much time time to reload the

application if I'm going to log

something

here now my application is running first

time it will take some time let me show

you the problem and what problem we're

going to solve and how we going to solve

that

problem

e

for

in this lesson I'm going to teach you

how to increase the speed of nestjs

project

reloading if I make changes in any file

let's say I'm going to delete this code

it will take some time to reload the

application I would like to increase

this speed with the help of web

pack you can see that it's taking too

much time to reload

application nestjs provides a way to

increase the speed of your hot

reloading you can see that it's still

calculating the

changes it's still calculating waiting

for the file

changes I think it has took 30 seconds

to load the application let's increase

the speed with the help of

weback first of all you have to create a

new file web H hot modu reloading doc

config you have to create this file

inside the root

directory and I'm going to copy this

code because I'm not not going to teach

you weac in this

course and step number two we have to

make some changes in bootstrap function

I can open the bootstrap function in the

main. file we have to add the code here

if module. H then you going to do this

process

it is asking me which module I going to

talk about let me check it from my

project yes I need to declare module as

a

variable

I can I would like to declare it here I

can also add that

part into my

documentation now our third step is to

add a script to use web pack instead of

default configuration to run the project

in development

mode we have to refactor the start dep

script I would like to change it and

let's do

it this time we're going to run the

project with web

pack

e

cannot find run script weback

plug-in do we need to install

it oh yeah we need to install

it

e

make sure you installed it as a Dev

dependency so I need to uninstall

it now we need to install it as a dep

dependency

let's run the

project

weback is building your

sources

project is

completed let's try to send the API

request but it's still

running

first time it will take some time to

initiate the

project now project has completed it's

time to send the API request I'm going

to send API request to root URL

let's say I would like to make some

changes I can

say hello world I saved the

application now you can see that it took

2 to 3 seconds to reload the

application updated modules you can see

that it also loged the message updated

modules so I'm going to move this

line application has started again I

found it's very helpful when you are

building a project in development

environment we're going to use Swagger

package to document the

apis if you don't know about Swagger

it's an OP Source software Frameworks

that enables developer to document and

design the restful web

services it provides a set of tools and

specification for defining the structure

end points and data models of an

API we will have Swagger specification

Swagger editor and Swagger

UI if you haven't looked at the Swagger

let me show you the

demo

this is the example of swagger

documentation you will have all the end

points what these end points are doing

you can look

at as you can see that we have profile

route we have all these routes available

you can also create a section for each

each route I'll teach you how to do that

so I just want to show you this is the

overall view of swagger

documentation so we have to implement it

first of all you have to install a third

party package which is nestjs

Swagger uh Swagger Nest has created this

package

let's install this

package or I can add into my

package.json

file let's install

it

Swagger package has installed now we

need to configure this Swagger module in

bootstrap function you have to do it

here you can use document Builder from a

Swagger

module you can have to set the title

title should be Spotify GL the name of

your

application and you can write the

description for your

application you can set the version and

finally you got to call the build

function and then we will create the

document with the help of swagger module

and you have to provide your application

instance and this config module this

config

setting and here we're going to mount

the Swagger document at/ API route and

you have to provide the application

instance and your document

I'm going to copy the same code and I'm

going to place it here inside the

bootstrap

function you got to do it

here let's import Swagger

module

I'm not getting the hints for Swagger

module and

document let's import

manually cannot find a module nestjs

worker

why

I think I have to install it

manually and install next just

swager now the error is going

now we have a Swagger

dependency

here we have the nest F

package you can write the name of your

title

application and you have to write the

description version and finally we got a

call the build and we are creating the

document and we have set up the Swagger

module it's time to run the

application oh there is an

issue it was an extra

parenthesis

application is running now let's try to

test

it I can go to the Local Host colon 3000

SL

API now we have the title of the

document and the

description we have all these routes but

we did not add the

tags I'll show you tags

in the next

video let's try to send the request to

the root

URL so I got this response hello I am

learning nests

fundamentals if I execute this endpoint

I got the

port the 200 status

code in this lesson I'm going to teach

you how to document this signup

route if you look at this signup

route I don't have any schema yet it's

not displaying the schema what type of

parameters do we need do we need first

name do we need last

name I also want to show the description

or the purpose of this signup

route

first of all you have to add the API tag

to the O controller let's convert all

these routes into o

section we're going to place the login

route into OD section enable to fa and

validate to fa let's do it first I'm

going to open the O

controller

here I can

say API

tags I can use the

Au my application is running

now you can see all the routes are

placed inside the O section

one more thing I would like to add in

the O

controller we have to decorate the sign

up route the next step we have to add

the API operation and the

response I'm going to use the API

operation we need to get it from this

Swagger

module

it will return the user in the response

with 2011 status code this is called

please register a new

user make sure it's running

now let's

refresh

I cannot see the sign up rout I think it

is taking too much

time oh I found the

error API

response we need to get the API response

yes we have the API

response let's restart the

[Music]

application

now you can see that we have the

register

user we have specified it

here somebody which is registered new

user and you can see the

response it should it will return a user

in the

response let's try to test it

if I if I provide first

name NH last

[Music]

name

shsf and we have to provide

email SN

gmail.com let's provide the

password 1 2 3 4 5 let's try to test it

out internal server

error because let me look at the error

entity metadata note found no metadata

for a user was

found I found there is an issue with

type orm and a web pack if you use vbac

hot reloading like we have used weac

package to reload the application fast

type orm does not work with this

configuration like this one we have to

replace it and you have to register all

the entities manually but it can work

with migrations there is no problem with

migrations but you have to replace it

here

we have to import couple of

entities application is broke

now I think I have to restart

it application is running fine let's

test it out I'm going to create a new

user a user has created successfully you

can see that with 2011 status

code when you look at the sign up

route if you check schema it is not

displaying me in the schema what do I

mean by

schema here I cannot see the login dto I

don't have create song dto I don't have

create user

dto it should display me the schema let

me run the

application

my application is running

now if you look at the schema in the

signup route you will see the empty

create user

dto you can fix it with the help of API

property you have to tell Swagger hey

this is the API property I want to I

want to see in this Swagger

document let's add API property in the

user

entity we have to do it here please

provide the first name of the user first

name of the user let me import API

property you have to do the same thing

for last name you can also add example

like what could be the data type look

like

I'm also going to add API property for

email let's do it for the

password my application is running

now but I cannot see this schema value I

cannot see properties here for my

schema you have to register nestjs

Swagger plugin you can do it in the nest

CLI I'm going to copy the

plugins open

nli and I'm going to do it

here let's restart the application

because we have modified

nli let's refresh the

application I cannot

see my

schema

I have to register the plug-in inside

the compiler

options that was the

mistake restart the

application now you can see the schema

value first name last name email and the

password it will also show you the

schema value for login

dto

here we have the user example value

email ID API key

playlist in this lesson I'm going to

teach you how to test Authentication in

Swagger

document we have to enable barer o it's

a

scheme you can do it in main.ts file you

have to add this function Nest Swagger

module provides this function add

barrier

o this is the type HTTP scheme is

barrier format should be

JWT name is

JWT you can add you can add the

description jwd token and I would like

to provide in the

header this is the name when you need to

use or apply on the controller

function one more thing we also need to

update the secret key in the JWT

strategy I don't want to use o constant.

secret I I have to get it from the

process.env

secret this get profile is our protected

route if you want to apply

authentication or app if you want to

protect or apply authentication of

swagger document you have to use the API

barrier a and this is the name we use

jw/ here this one

like create songs endpoint is also a

protected route you can also apply

authentication on that in the songs

controller these are all the protected

routes only

artist can access update endpoint delete

endpoint and create endpoint so you can

apply Authentication

on these routes as

well but I just want to show you the

demo in the app controller we have this

protected route get profile

endpoint let me show you in

our Swagger document SL

API here we have login

route we don't have any authentication

section let's implement it first of all

let me write documentation for login

route inside the O

controller it looks

good now we have to enable the

authentication I'm going to copy the

code and paste it

here now we have to apply JWT

authentication we also need to update

the secret key in the JWT

strategy

I don't want to use o secret from the O

constants let's get it from the

environment

variable and this is we have to

use I'm telling to Swagger hey Swagger

this is the protected

route application is broken now restart

the application I found an issue when

you are working with we hod module

reloading do not save the application if

your application is in error

format if there is an error in the file

do not save the application otherwise it

will break the V hod module reloading

now it it will take some time

to restart the app

application application is running

now I have to refresh my

page now you can see the

authorize if I try to access the profile

route from

here it should give me the error unauth

red so you can you have to log in to get

the access

token I'm going to send the login

request password does not match what was

the password 1 2 3 4 5

6 I have got the access token

now I can use this

token and I'm going to provide it here

this is the name JWT o you can see that

authorize

Now by enabling this JWT o

here this Swagger will use this token

just like we saved

here

let's access the protected

route you can see that I got the user ID

and the email it has already

attached authorization barrier and the

token if you have all protected routes

in the controller you can also add API

barrier or

here for all controller routes but I

have only single route is protected

protected this is the public right route

that is why I did not use the API or o

barrier or inside root inside the

controller for a

controller so I applied separately API

or API barrier OD

you can also Define the tags for songs

controller I want you to do

it you can apply High authentication on

songs controller protected

route like create is a protected route

you have to add API or o barrier

decorator

here it did not create the aay tax

because my application has broken now by

using this code restart the

application my application is running

now I can see all the songs related

route you can also do it for the

playlist API

TX

you can see the playlist

section in this lesson I'm going to

teach you how to install mango DB using

docket

compose if you don't have installed

mongod DB on your machine you can

install it manually or you can install

with Docker compose I have already

installed Docker on my machine my Docker

is

running you can see that here is my

Docker is running

now but we don't have any project right

now to use with

mongodb I don't want to install mongodb

in my previous project we're going to

create a new project to play around with

mongod DP

database I want you to create a new

project

I can say Nest

new and we need to provide the name of

your project I can

say n

production nestjs

project with mongod DB and I want to

ship it on production level you have to

choose your package manager I'm going to

use

npm it will take some time to install

the

dependencies my project has created

successfully all the dependencies have

installed I'm going to go to my

project I'm going to open the project

into my vs

code

let me run the project by using npm Run

start

Dev let's commit in

it and I would like to create a new

Branch I'll store this code into this

branch

[Music]

to connect with mongodb we will install

this dependency or this package in the

next video or you can install it

here we need NCS mango package and we

need mango separate

package this is the magic we need to

implement we're going to use docket

compose to start mang DB

driver I'm going to create a new file in

the root directory I can say Docker

compose

EML you have to Define your

version I can say one you have to define

the

services here we need to define the

service mongod DB or mango

mongodb the name of the

service you have to provide the

environment I can

say mongod DP

database and we need to provide the name

of the database which is

test we also need to provide the image

we need to get the local uh latest image

from the docker

repository Docker Hub or you can say

let's define the port I'm going to copy

the same code I don't want to make

mistake that's it or you can change your

database I can say

Spotify

clone now you have to start MB

driver you have to execute this command

do compose

up my project I'm going to open my

project into R directory and let's

execute this

command I

think already allocated I think my

already project is running

on 2701 docket compos let me stop that

project

project here we need to stop

it let's try it

[Music]

again now it is going to start the

mongod

DB I'm also going to use external tool

it's a graphical user

interface mango DP Compass you can

install it you can play around with GUI

with mongodb database this is the GUI

mongodb mongodb

Compass you have to have a new

[Music]

connection you can have a new

connection it is going to ask me the

host and the port I can say Local Host

and this is the port

2701 because my mango DB is running on

this port 27017 so I'm going to connect

it and you can create a new database

Spotify clone and you can have the

collection which is

songs you can see

that I have interacted with mongodb

database and I created a new

database

so our mongod DP driver is running

successfully in the next video I'll

teach you how to connect nestjs

application with mangos or mongod

DP in the previous video we have

installed these two packages

mangos and nestjs

mangos if you would like to connect

nestjs application with mango or mango

DB

you have to create a new module in the

app module you have to create it by

calling the for root method this for

root method is similar to mango. connect

from the mango package you can read the

connect package from the official

documentation what I want you to make

sure your mongodb is

running my mango mongod DB driver mongod

DB is running with the help of Docker I

use Docker compose

up here it is running Docker compose

up now we have to call this method

mongos module. forward in the app

module make sure you have this database

Spotify clone if I run the application

let's see what will

happen

npm runs start

def mango module because we did not

import it let's import it with the help

of VSS code I'm going to save the

application

you can see that Mango's package has

installed it has also initialize the

mango score module

dependencies it means we have

successfully connected to mongod

DP if I will write the invalid Port

let's see what will

happen

I'm getting the error mangos module

unable to connect the

database so it means we have configured

the mango DB with

nestjs but if you look at mango

Compass I think I don't have Spotify

clone

database it can work without creating

the database if I create the database

it will

work I can create the name of the

collection now we have Spotify

clone it looks

good now we're going to create schema

using mongos

model in mongos everything starts with

schema each schema maps to mongodb

collection and different finds the shape

of the document within the

collection schemas are used to define

the models and models are responsible

for creating and reading documents from

the mongodb

database so we're going to create the

first

schema you have to create a new folder

songs here you have to create the

schemas folder and you have to have a

schema which is songs. TS file but we

will use this song document when we will

inject the model into song

service you can use the decorator schema

nestjs mango module provides schema

decorator this prop represents the

property in the

collection we will have songs collection

and inside the song collection we will

have these Fields Title release date

duration

and the

lyrics Yep this schema decorator marks a

class as a schema definition it Maps Our

Song class to mongod DP collection of

the same name but it will add S at the

end of the final mango collection name

will be

songs and prop decorator defines a

property in the document and finally we

will have schema Factory

it will return the raw definition of

schema I logged on song schema and I got

this result schema object we have these

properties title release date and

duration and couple of metadata for each

field this is how you will create a

schema I want you to implement

it

so I'm going to implement

here by creating a new

folder inside these

songs we will have

schemas here I'm going to create a song

schema or song. TS

file

I just pasted my

code we have defined four Fields I got

all these properties from our previous

project which we worked with tym and

post I got title release date duration

and lyrics I set this data type for dur

string I couldn't find a Time Field Time

data type in mangos so you can validate

manually duration by using third party

date

plug-in so we created the schema

successfully this lesson I'm going to

teach you how to save record in mongodb

database we're going to save record card

in mongod DP

collection right now we don't have a

songs module we don't have songs

controller we don't have song surveys

we're going to create all these stuff

and then we're going to create post end

point inside the songs controller you

have learned how to create the post

endpoint how to create network request

object or data transfer object

dto and then I'm going to use song song

service song service has create method

to save the record in mongodb collection

and finally we will create create song

dto object inside the create song d.

file and here I would like to inject the

model remember schema will act as a

model you can use schema to generate a

model so I'm telling please give me the

model

the name of the model which is songs and

I would like to use here I would like to

inject it as a dependency I remember I

have created the type in the song schema

file I got the song

document and this song model provides

crud operation create read update and

delete it is similar to type orm

repository it will be treat treated as a

type RM

Repository and finally we have a safe

method in the song model and I am going

to call the method here it is going to

return the

promise and finally we have created the

songs

module we have to inject the song model

just like we did with type orm

repository if you will not do that part

you will not be able to inject song

module here that's why you have to

register it as a here I'm telling to njs

I would like to use song model in the

service or in my

provider and then you can send the

request to this

URL to to create a new song in the

mongod TB collection I want you to

implement

it let me implement it for

you let's

generate let's generate controller

songs let

generate so

service

songs it has created the songs

module it has also updated the entry in

the app

module you can also see the songs

controller it has also updated Creed the

songs controller inside the app module

you can see

that now we have songs

module inside the songs module we have

songs controller and the song

service now it's time to create a new

endpoint I'm going to copy the code

inside the songs

controller we just injected the song

service right now this create method

does not exist in the song

service we also don't have create song

dto Let's create let's create create

song

dto I'm going to create a new folder

dtos and I'm going to create a new file

file create song hd.s

file that's

it I already taught you how to create a

method in the

service let's refactor the song service

add a new

method we have injected the song model

make sure you provide the name of the

song model here we are injecting the

song model and I called called create

method from song

model and finally we have to tell njs I

want to use this song model in the songs

module so please make it

injectable and now we have to run the

application

I have to import

song dependency

song

it looks

good we have to test

it I'm going to create a new file to

make API request I can say api.

HTTP let's send the API

request

you can see that a song has created we

can verify from

Compass here is the record inside the

songs

collection let's add another

song

so we have another

song it should display the second song

but I cannot find

out no I can see the second

song we have two records in mongodb

collection this is the

document if I don't set the title what

will happen you will see internal server

error because we have set the

validations inside the song

schema these properties are required

title is required release date is

required and duration is required

in this lesson you're going to learn how

to implement find and delete method we

will create two endpoints to handle

find and

delete

request let's start implement it I have

already taught you how to implement crud

or rest based API end

points let's create a method find to

fetch all the records from mango DP

collection it is going to give me all

the

documents now we have to create a route

to handle the

request

our application is running now let's

send the API

request to fetch all the

songs we have to send the get API

request we don't have any record yet

let's create a new song I have I've

created a new song I'm going to create

another

song now we have two songs let's fetch

all these

songs we have successfully implemented

the find all

method now it's time to implement the

find by

ID

I'm going to create a new method find by

ID in the song service and there is a

method find by ID in the song model you

have to provide the ID we're going to

get the ID from the request

parameter let's create a new

route

now we are going to send the request to

fetch song Only based on

ID find one

song we have to get the ID I'm going to

send the request to fetch all the

songs now I'm going to copy the ID and

we need to provide the ID

here so I got the single record on the

based on

ID you can also implement the delete

endpoint I'm going to create a delete

function inside the song service

song model provides delete one method

and you have to provide the ID mango

work works with underscore ID if you

have worked with mongodb the ID

stored ID stores in this underscore ID

format if you if you are using or have

used postgress or MySQL in my SQL or

postgress you say the primary key or

primary ID with this ID without

underscore now we have to create a

delete endpoint in the songs

controller we have to get the delete

method that is

it

let's create a new

song because we're going to delete that

song I'm going to get the ID and now we

have to delete the song to send the

delete API

request delete

song you can see deleted count is one

acknowledged true it means we have

successfully deleted the song you can

double check it by sending the API

request to fetch all the songs and you

can see new song does not exist

here you can also implement the update

functionality I already taught you when

you were learning type or mcard

operations similarly you can implement

the update operation you can have you

first of all you have you have to Define

update function Here song model provide

the update method you can use that

method and then you got to create a

controller to handle the update

request in this lesson I'm going to

teach you the concept of

populate if you want to make a relation

or a reference between two document

between two collections remember in

mongodb

collection collection will have

documents in my SQL or post you will

have tables and

columns so if you want to make the

reference or relation between two

collection you can do with the help of

poate you have to implement the concept

of

poate I have this use case or scenario

each song must have must belong to one

album and each each album can have many

songs I want you to implement it if you

want to do that you can Google Mongo's

relation or check the official

[Music]

documentation this is our

album schema we did not create the album

schema yet I'm going to teach you how to

do that or you going to create or you

can create the album schema just like we

did the song schema scha it is going to

take the array of the songs because each

album can have many songs that's why I

created the array of songs and you can

have multiple

types it's an array I got the types from

mango package here you will see type

from the mangos and I'm telling that the

reference is

songs because when you create the song

when you created the song schema you

have defined a class for class song by

default the collection will be songs you

can also double check it from mongod DB

Compass let me show

you I'm telling you I would like to make

a reference with songs

[Music]

collection let me do that

inside the Spotify clone we have the

collection name which is songs I have

added the reference

here and finally you also have to add a

relation for this for the album in the

song schema I'm creating a property and

type should be Mango's object ID or

mongodb object ID here I'm I'm getting

the or defining the reference album.

name it should be

albums and we have the album and finally

you got to create album module just like

we did the song module and I'm saying I

want to use the album model in the album

service or we we will be able to inject

the album model to perform crud

operations and here I have injected the

album model in the album service just

like we did songs model inside the song

service and I created a new method we

will have a create album dto and here we

will have find

albums this is how you will implement

the populate let's say you want to

display all the songs on the front end

against each album then you need this

query you got to I'm telling to mongod

DB please give me all the albums please

give me all the albums for each Album

please also give me all the songs this

is how you going to do

it and create when you are trying to

create a new album you got to provide

the title and the songs it should be the

IDS and we have create method to create

a new album

and uh find all albums and you also have

to refactor create Song D you can

implement it I want you to do it I

already taught you all of these steps to

do

that first of all we have to

create album nextest

generate nextest generate module

albums or I can say

albums and next gener at

controller

album and Nest generate service

albums Nest generate

module albums

Nest generate

controller

albums Nest generate

service

albums

I don't need spec files I'm going to

delete

them now you have albums module albums

controller and album service it has also

added the entry in the app

module let's create a new folder

schemas I have to create create a new

schema I can name it to album

schema. we will also need a

dtos now we're going to I'm going to

copy album

schema and I'm going to paste it here

that's

it

and I can

use I also have to refactor the song

schema we have to add another property

one thing I forgot to add it should be a

mongodb property that's I forgot to

add add prop decorator for the lyrics

property we need to get the types from

object

ID from

mango we also have to import the

album from album

schema everything is good right now

let's

create we have to

update album

module actually we

need we need this line I'm going to copy

[Music]

everything

e

we don't have dto let's create

that create Alum

dto now we have to

define a

controller we already created the

controller I can

say should be albums

controller album

service and we also need to refactor the

create song

dto

I have found the error in the album

service get rid of the song Let's import

it

here if I save the

[Music]

application we also have to

refactor in the song

schema

everything is good

now what we what I want to do I would

like to create the album

first create

album we have to send the post

request by providing the

data it is going

to get give it is going to asking me the

name of the

album title title of the

album let's say

dance and I would like to provide the

array of the

songs I want to save let's

say these two

collections

these two

collections inside the dance inside the

dance

[Music]

album I'm also going to save this

document or save the song inside this

album let's create a new

album

I got the

eror song validation

failed duration duration is required

OMG I forgot to add the albums

here now you can see that I got the

dance album with these two

songs now we have to fetch all the songs

I'm going to test the popular method

popular

functionality find all

[Music]

albums with

songs this time we have to send the get

request let's fetch all the

albums you can see that I got the albums

array this is the first album and we

have all the songs against each album

this is how you can make a relation or

reference with document with

collections or with

models in this lesson we're going to

prepare our application for

deployment I'm going to teach you how to

deploy nestjs application at

Railway you will also deploy your

postgress

database at Railway we're going to

deploy our application this one the

Spotify clone which we were

building our application is using postp

database with type orm I'm going to

teach you how to deploy the complete

application at

sailway

first of all you got to create a new

project make sure you deploy your

project at GitHub

repository I did not deploy the project

yet first of all we have to do a do a

little bit

configuration we have to set our

environment variable when I will run the

application in production it should run

this production. EnV file if I'll be

working at development environment I

want to work with local post database I

don't want to change in production

level so we got to configure a couple of

settings we already created the env.

development. env. production but it is

not configur configurable when my

project is running in production mode it

should pick this production

file I've already written down the

validation in EnV validation for node

environment but I did not set in the

configuration

let me do

it I can say node

EnV and I can get the value

from process

dot process. env. node

EnV now this variable is available for

the config

service I've already provided you the

nests deployment raway started kit BR

started kit project you have to open it

and run npm install to install all the

dependencies now we have to configure

the EnV file path in app module

get rid of this

stuff I don't want to do

it

configure get it off this

middleware get rid of this data source

here we have to update our

path what I can

say please get the value

from process do

do

EnV do node

EnV or you can say get the path from the

current working directory and you can

provide the name of your

file current working

directory and

Slash

dot here we need to do EnV dot

development or

production we have to remove this

one

please get the working

directory and find the env. production

file or env. development

file we have to set the script or we

have to set the development environment

in our package.json file for the dev I

can say I want to mention node EnV to

development we have to do

it here we have to set the production

value when you run the application with

production how can I test

it in the main.ts file maybe I can use

that or what can I do yeah I have the

access to config

service I can say console

DOT

log

config

service

doget I can provide the name which is

not

EnV

let me part it to

string let's see what will

happen you can see that it's working

fine now my application is running in

the development

environment if I run the application in

produ prodction

environment when you see the production.

environment I don't set the I didn't set

the database configuration so it will

not work my application will be crashed

let me show

you you can see that my application has

crashed

an instance of environment variable has

failed

yeah it is showing me the validation

error dbport does not exist DB host does

not exist if I copy this

configuration what will

happen now it should run the

application you can see that my

application is working fine

now but we will replace these

configurations with Railway post

configuration I have everything in the

master

Branch let's create the GitHub

repository because Railway will be

asking for GitHub

repository let's create a new repository

I can give any

name nextjs deploy to

railway

if you want you can create private

repository I'm going to make it

public we have to add

origin it is asking me to create push as

a main

branch let's do

that so I got the main branch everything

inside the main

branch let's try to check it

out so I have everything in the main

branch now we

have we have EnV doev development we

have env.

production you should not push your env.

development or env. production to the

GitHub

repository because we wanted to set it

to the kit

ignore do not add

Dov

files if I add.

EnV update get

ignore

we have to push the

code I try to add do EnV in the G ignore

edit I try to

add EnV in the

ignore and it was not not

working I also removed the cache for

env. development and env. production

file

removed

envs now we have to push

it

oops envs

let's push the

code

let me delete this file

manually I'm also going to delete env.

[Music]

production

now we got to pull the

code everything is up to date right now

if I try to

push you should not

see env. production and EnV do

development

file so we have pushed the source code

to our GitHub repository you going to

say deply from the GitHub

repository here we have to configure

our repository I can say deploy njs app

to I can say now it is going to deploy

the code

it is

building and running env. production no

it is trying to building the

project

now you can see that our project has

deployed if you want you can see the log

what is going on

here I got this

error instance of environment variables

has failed in the valid

validation that's an issue we have to

configure our environment variables

our application has crashed now we have

to set the environment

variables first of all I have

to create a new database it's very easy

to create a database in real

way just right click and find the

database I'm going to have

post now you can have the

post when you see the connect here you

can find your database

option I can say this is

post and you can up create your EnV

production file

EnV

[Music]

production oops I deleted that

files we need to get back our

development. EnV

file do env.

development and I also need to get

production EnV

file now I'm going to copy my

database in the

production let's do it

here

[Music]

database this

[Music]

one and we need PG

Host this

one and we need password I want you to

use your own password do not copy my

password

username it should be post it's working

fine you also need a

port everything is good to go

now

now I want you to copy these EnV file

the your production EnV

file and open the N nestjs deploy to

raway

project and in the in in the variables

you have to set your environment

variables that's it I'm going to update

my variables now it is going to redeploy

the app

application now redeployment is in

progress It's Time to it's it will take

some

time my application has deplo

deployed now it is going to start let's

look at the deployment

logs amazing I I was logging the

production in the app module or I think

I was doing in the main.ts file you

should not do

that it's working fine it means we

successfully deployed our

application so how can you test it maybe

you had thinking about it how can I test

this application right now we don't have

any domain let's generate domain to test

the

application uh if you want to refactor

you can change that I can say Spotify

clone

production now we have this domain name

I'm going to open

it it is going to give me the nothing

here don't worry when you try to access

the API

routes it will take some time because we

have set the domain

name it is going to take some

time now it's working I think fine

now after 30 seconds my project has

Reloaded

now we're going to figure it out I'm

going to send the API request to test

the application it is working fine now

but what will happen if I try to create

a new user let's say I want to perform

database operation I'm sure it is going

to give me the

error let's create a new

user

Jane

Don Jan

gmail.com 1

2 3 4

56 I'm going to send the

request I got internal server

error you can check the log what what is

going

on users does not

exist because my database is empty now

we did not implement the migration

remember you have seen in the data

source we have set this synchronized to

false but do not use synchronize to true

in

production what we have to do we have to

run our migrations to perform changes we

have to add relations because I done

that I've done

it I think I don't want phone migration

you can delete

that

now I have to execute these queries

these queries will create table

in our postrest database here

here what we have to do we got to run

the

migrations I got this issue we have to

migrate the database in the production

so we have to use a

migration make sure you are using the

password process. env. password not a DB

password because we have defined the

password in our environment

file we have to run the migration I'm

going

to run the script npm run migration I

would like to create all my tables

that's why I just provided the name in

it so I got the

undefined

process. I'm doing the log for node

environment I'm also doing the log for

DB DB host I'm also doing the log for DB

password you can see that I got the

development value it is working fine but

when you look at the env. development

I'm using the database for the Local

Host like post gra local instance here

I'm using the railway postra

instance so I have to tell to nestjs

build

command under the they are using

generate command is using njs build

command this one type orm but I want to

say please run the produ run the project

in the production let if you want to run

the de in migration in production you

have to Pro tell njs project you can

create a separate script for build for

production or separate SCP for separate

script for build in the development

environment but you can do quickly by

using say that

export node EnV here I want to set the

node environment variable to production

now you can see development environment

should be in the

production I'm going to run the

migration I've also logged the node

environment it should give me the

production by default

it if it if it logs

production it means it is going to run

the production EnV

this

one you can see node environment is

production but I got DB host is empty

undefined and password I figured it out

the issue I have to

install do EnV

package and here we have to use the EnV

package it is not getting variables from

EnV because we were using the config

module for config

configuration after installing config

module do EnV

package you have to import it

here do en/ config now you should be

able to access these variables

so I'm going to run the

migration

before running the build you have to set

the node envirment do you want to run it

for production or do you want to run it

for development but if you want you can

create a separate script SE separate

build script for production and

development I still got the

eror production

it's not getting the

value I think it is not finding the env.

development

file so there was an issue it is not

loading the EnV from the env.

development. env.

production if we will have simple. EnV

then EnV package can get variables from

the file but right now it is not getting

it so you have to provide the custom

path I just did a little bit

configuration we have to import the

path we have import the

part so we have to

use this

syntax

require this

one all I have to do is provide the EnV

path

now it should work it should get the

values so I'm going to create the

migration cannot read

property

PA is equals to

path

but I got still

undefined let's log EnV

path oh it is getting the value

from

DB but my file is located

at root folder so it is not here inside

the

DB if I try this

one I tried to work with this env.

production with custom path but it is

not

working all I did if I

change EnV it is it will work let's let

me show

you get rid of

[Music]

everything now if I copy that and

create EnV file in the root directory it

will

work I found there is an issue with type

orm now I'm going to paste my

code for production

you you have

to adjust nestjs build when you try to

run the migration you have to update the

changes here I found this is the way you

can implement it but there was an issue

with custom file path so now it will

work I'm going to run the

migration now I can see production and

the my container name which is my DB

host and my password now migrations has

been generated

successfully it's time to run the

migration we got to run this

command npm

run

migration

run should be

run you can see that it is running all

the queries creating tables in the

railway postris

database now you can understand you can

use this EnV for type orm

build use it for type or RM

migrations because in the app module we

are using the configuration of config

module we are not loading this EnV file

we are loading envir environment

development env. production file but you

can use this EnV for

migrations now we need to double check

it

we have to deply our

code now it will take some time to

redeploy the

application the application is running

now I got this secret key the database

host and the

password now we're going to run

it/ API open this Swagger

tool you can also double check it from

postris

database I have only migration table it

should give me all the tables but

something went wrong

here inside the

migration the record is empty table is

empty unique key primary key what is

going

on oh I have two migr

ations get rid of this

file get rid of all these

migrations let's generate the migrations

from the

scratch I'm going to name it to in

it now migration has R it

successfully I'm going to comment this

code now you have to run the

migration everything is good to go all

the ques has have

executed now you should see the data in

the data datase you can see I got artist

playlist songs and users

table we have these

columns if you want you can run the

seed from App module I think we we were

doing seeding in main.ts

file you can enable this

code application is running

now let's create a new user

amazing we have created the record

successfully you can also double check

it from the post

database you will have the user

here but I created this user

from the this one from seeding because I

think my seeds are running

constantly I think I enable that seed in

the app module we got to disable

it otherwise it will generate more

users I'm going to remove them now you

have to see constantly a new

data I can say disabled

seats now it is going to redeploy the

application so this is how you can

deploy nestjs application to

railway in this module I'm going to

teach you how to do unit testing

integration testing and end to end

testing for nestjs

application before getting started on

testing I want to teach you some of the

basics of just because we're going to

write a lot of mock functions we're

going to write we're going to write a

lot of spying spy

functions you will learn how to create

Mo implementation of service of a

controller of a

repository if you know the basics of

justest if you know mo functions if you

know spy function then you can skip

these three

lessons if you want to refresh the

knowledge of just you can continue this

video just as you if you don't know

about just just is a popular JavaScript

framework it is developed by

Facebook you can use for testing

JavaScript

application you can use just with react

view angular and

nodejs these are all the function alties

of the Gest asynchronous testing code

coverage snapshot testing moing and

spying we're going to use a lot of

moking and spine with nestjs that's why

I want to teach you these two concepts

in more

details you will learn how to do matches

and test suits and test running and

assertion uh before creating the just

project I want you to open an empty

folder we're going to start it from the

scratch and you got to create

package.json

file I can say npm in it d-s please

create the package.json file for

me I got the package.json file now I'm

going to copy

that and let me replace

that here what I want to

say we we need to install the typing of

the justest we need to install the

justest app a Dev dependency and I

created the script to test the justest

if you want to run the justest in watch

mode I'll teach you how to do that you

got to run you got to run this

script so uh please install these two

dependencies I'm going to install

them it's going to install the

dependencies let's create a new file I

I'm going to name it to some .js file

we're going to test this function we're

going to write test cases to test this

function in the third step we have to

create some.

test.js file I'm not using typescript

here I just want to show you the basics

that's why I want to keep it more

simple we have to import the sum

function from the sum. JS file

I have to write the test case at 1 + 2 =

3 now we're going to write the test case

you can use the

test it should give me the

result 1 + 2 =

3 so we're going to call this

function it's going to take the call

back

function I can

say

expect it's not giving me suggestion

because it is taking too much time to

install the

dependencies because I think my internet

connection is slow right now

so we need a

[Music]

function sum. 2 B 3 we have to call that

function it is going to take two

arguments if you look at the sum. JS

file you will see two arguments A and B

the first argument I'm going to provide

one and the second argument I'm going to

provide two let's try to test it

out it's still

working npmi minus

TJ my both packages have installed just

in the typing of the

just now you can write the test case

I've written the test case you can run

it npm run test I would like to run it

in the watch

mode dash dash watch is not

sported so you have to write the watch

all now you can see that I have to

update the script for the watch

all now we have to select the pattern I

would like to run this s test.ts file

right now we have only single

file it's going to execute this file the

test has passed now if I write the

invalid value I save the

changes it has started automatically and

I got the

error expected four but received

three you can play you can play around

with multiple matches function let's

say 1 +

4

or to have been

called to have property to have

returned to have returned with let's say

five you can play around with multiple

watches received have as type

number so this is not a right matcher

function so I can say it should be

five this is how you will write your

first test

case now I'm going to teach you the

concept of

mocking we're going to play around with

mock functions Auto mocking inest refers

to the automatic creation of mock

implementation for imported modules or

dependencies during

testing let's create the mock

functions you can use the mock function

to track the function calls

if you want to remove the dependencies

we're going to do in njs testing we're

going to remove maybe the implementation

of service implementation of the service

then we will have more implementation we

can simplify the testing and control

behavior when you do the unit test your

code let's say if your code is dependent

on five dependencies let's say if your

class is dependent on on Class

B Class

B Class

C or class D let's

say and you want to do the unit testing

let's say this is the class A now Class

A is dependent on let's suppose Class B

Class C and class

D now Class A let's suppose we has two

function or one function if you if I

want to test the one function from the

class A when you do the unit testing you

test the individual Parts you test the

individual functions to test the

individual function maybe the individual

function of Class A is dependent on the

function of Class B function of Class C

and the function of Class D then we have

to write the mock implementation for the

class B Class C and the class D

I'll teach you in the later

videos now we're going to create mock

function this is how you will describe

or you can group all your test cases

into a

group describe I want to write all the

mo function examples in this

section it is similar to the test you

can Define the it or the test it is

referring as a test so it should create

the basic mock function let's create a

new file Mo function. spc. TS file I

have created the test.js file but you

can also create the

spec. JS

file the concept is same

now now we have to write the mo

function here I can

say

I will provide the

mo write Mo function

examples here this this this section

will have the mo function

examples let's write our first test case

it should create a basic Mo

function should create a

basic mock

function

you can create a mock function by using

the just. function I can say this is the

mock

function just provide is a

FN now we have the empty Mo function if

you log the mo function you will see

this is the empty function let's try to

do it run the script again to run the

Tex test in the watch

mode this time I'm going to add the

pattern for the more Dash function. spc.

file it is going to ask me the pattern I

can say mock now it's going to run this

file if you see the log you

have a function a mo function if I call

that you will see there is nothing here

we have undefined

function if you pass the argument it is

going to still it is going to still give

me the

undefined this is the empty mooch

function if you want to return the value

from the mock function you can also do

that

return

value Mo return value now let's say I I

would like to return the

four now if I call that function it

should give me the value of four I can

write the match functions on it mock I

call the

function to be the value should be

four you can see our test has passed now

if I add the invalid value which is

three it's going to give me the error

expected three but received

four if you want to remember I told you

you can also keep track the calls of the

function with the help of Mo how many

times this function has cost

called mo. calls.

length to be we have called

only one time so it should give me the

length is

one if I call the function two

[Music]

times Mo

function

dot to

have been

called

been

[Music]

called let's say I want to call that

function and I'm expecting the four

it should give me the error you can see

that the save to expected is one here we

have the

error it should give me the two because

we have called this function two times

if you want to keep track of the calls

of the function how many function have

how many times you have called the

function you can also do measure on

that here I can say expect

mock function to have been

called it is checking that did you call

the function yes we already called two

times this is how you you can return the

value from the mock function you can

create you have learned how to create

the basic mock

function

now you're going to learn how to create

a basic Mo function with

arguments we did not create a function

with

argument we just created a basic mock

function then we have returned the

value here I can

say it should create a mock

function with an

argument

let's create a function con

mock song function you can say song

mock just.

function it can have create song dto

let's say

that

mock create

song and this

function will have this

argument but I also want to write the

implementation you can do that as well

well right now we did not return the

value if you want to return the value

you can

do this stuff it is going to return a

song

title animals and

ID or you can oh

animals and ID which is one let's say

that

that if I am expecting on

that it should give me the same

object

animals ID which is

two or ID which is one if you want to

test the object you can use this two

equal

expression make sure you have called

that function with

argument create D is not

defined title should be

animals create D is not

defined I think it will not not work we

have to write the implementation here I

just want to show you the another

alternative path it's a call back

function it's going to it's going to

return the create song

dto now you

can look

at this

one

now my test has passed now if I will

write the ID it should give me the false

it should give me the false value or it

has failed because I am just returning

the ID but you can pass this

test if I create if I return the

object use the spread operator and ID

which is

one let's try to check it out

out now my function has my test has

passed

now if I provide the another value

lower in our application this function

like create song function does not exist

here we don't have a create song

function we don't have njs project we

don't have repository we don't have

service controller that's why this is

how you can create the mock

implementation you can also create a

mock function with mock

implementation we used callback function

here here but if you want to

use this Mo implementation you can do

that as

well it should create a mock

function with an

argument with Mo

implementation this

one I don't have preer

file R

see single C to

true because I use this prettier

formatter now my code has formatted

now we're going to use the same

approach const mock create

song just.

function I have defined the

function mock create song do

mock

implementation create song

dto it's going to return the object

create song dto and the ID which is

one now I'm going to ex run the mat to

test the

code my code has passed now my test has

passed now you can approach you can

implement the same stuff by using the

call back function here or if you prefer

the mug implementation you can do in

this

way now I'm going to teach you how to

create a mo function and it function

this function should return the

promise all you need to do is call the

mo result value we use the mo return

value you can do that with the help of

Mo resolved

value let's say I would like to create a

new

function

let's create a new test case it

should create a mo function with

promise ultimately it it is ultimately

it is going to return the

promise fetch song data or you can say

that fetch all the songs from the DB or

you can say the network

request now we got a

return Mo return or Mo resolved

value let's say fetch songs I got the

array ID

one title

Lover now I will like to call that fetch

[Music]

songs Doc do

results dot to

equal if you want to apply assertion on

promises you can call the results

property and then I can apply this

Expressions to equal this

one make sure you could to call that

function now my test has passed if I

write fetch I'm going to call the fetch

functions do

resolves dot to have

length it should have

one my test has passed if I write the

two it should give me the error because

we have only one property in the songs

array I got the

error I'm going to call it with

one this is how you will do the

mocking you have learned the feature

Auto moing which is mock

functions but we did not talk about the

spank and you can control the

behavior

and you can assert on their usage during

testing you can create the function

spying on spy you can spy on a function

by using the just. spy

on it allows you to create a spy or a

mock function for an existing object

method if you want to spy on existing

object you can do that if you want to

spy on existing class you can do

that now we're going to spy on an

object we have an object spy on a method

on the

object we going to Let's imagine we will

have the song repository and we have the

create method what I want to do I want

to spy on the create method I don't want

to use this implementation I want to use

my fake implementation in under the

hood just will tell you you I called

this function but I have used your

implementation this implementation this

one instead of instead of using this

original

implementation let's spy

on I want to I want you to create a new

file since by on demo dopc

dots let's create a song

repository and we have a create function

let's imagine we have a find

function let's imagine we have the find

one

function I want you to add the add this

Pi on this find find and find one but

first let me do that find one will

accept the ID let's

imagine the

ID now let's create a

[Music]

function so I created the test case it

should spy on the

existing method

function object

method so you can create a function on

this py

on

so this is how you will spy on the

function it should also give me

the toll tip

create if I log this piy function let me

show you what is inside

that I have to run this file

P I want to spy

on it's going to run this

file my test has passed but this is a mo

function if I call

that it should give me nothing because

it's an

[Music]

undefined what what if I call the

function SP and I'm going to call

it not an ID let's provide the

title or let's say if I call the

function

[Music]

function of this song

repository you will see the

magic I have called this function now my

function this function is pying on this

function what will

happen if I log

spy do

mock do

calls it should say I have been

called with this argument

array it's an array mo. length which

should be

[Music]

one it is saying I've been called only

one time by using this one if I call

song repository. create let's

say

title new

song now the length should be

two you can see

that if you want you can spy on the

function spy do to have been

called now my function has been

called expect

spy you can also say that to have been

called called

with called

with title should be

lower it is fine now if I say lovers it

should give me the

error you can see I got the

error you can also track the how many

times this function has called to have

been being call times it's going to give

me the

one I'm spying on this function song

repository. create similarly you can spy

on the find and the find

one you can also spy on a class I'm

going to create a new

class we

have let's say I'm going to place the

Clause here we have safe method in the

artist repository I want to spy on this

function but you can also write the

implementation just like we did it we

can have our own custom

implementation I call this

method now you can see

that to have been called times to have

been called with at the end you can also

restore the

mo but I would like to do this one after

each please restore all the mocks this

is a hook after

each it is going to run after all the

test in this section in describe

section now we're going to copy

that test case and paste it

here

we have created a new instance from the

artist

repository and I call just. spy on I

want to spy on the save function but I

also want to add my

implementation it is going to return the

create artist dto or it is going to

return you can say

that I would like to return the

object create artist dto and I want to

add the

ID now you can see that spy it is going

to call this function artist. save what

is here I called spy name and it has

returned Martin Garrick and with ID

which is one and how many times to have

been called yes expector to have been

called with name we provided the Martin

garx

spy and I don't need to do that because

we are doing it

here

expect

spym do calls. length how many times

have you been

called I think I did it one time

rt. everything is to have been

[Music]

hold with two

times also called artist. save and I

also called it

manually now it looks

good in this lesson I'm going to teach

you the concept of unit testing in

nestjs when you do unit testing you test

the individual component of your

application individual component means

individual function of a controller of a

repository of a

service we have song song service I have

attached this started kit project you

have to open it and run npm install you

got to install all the

dependencies we have uh we have this

song

controller when I'll be talking about

unit testing I mean I have to test

individually this function get song get

songs create song and update song and

delete

song but you notice the song controller

is dependent on song

service here we need more implementation

of song

service

because I want to test individually this

song controller but when we will do end

to end or integration testing when you

will test the end to end you will

integrate all of your services all of

your classes all of your

dependencies you can verify your unit of

code such as fun s methods or

classes with the help of unit test you

can find the bugs earlier you can

improve the code quality you can do

faster debugging you can refactor all

refactor code very

easily now when you run the source code

when you run the test for song control

dopc file nestjs already created this

spec file for us if you run that it is

going to say hey when I look at the song

controller I saw dependency There song

service but when you are creating the

testing module here we are creating the

testing module on the Fly n sjs will

compile it when it will comp compile it

will instantiate all the dependencies

for the testing module here it is saying

I'm depending I'm dependent on song

service but you are not providing any

song service here you not providing any

provider let's

say you are not any provider song

service so it will give me the

error because we are doing unit testing

I don't want to include song service

here I want to test individually these

components but I'll teach you how to

fake how to create the fake

implementation of song service here we

are getting the controller from this

module and it should be defined this is

the first test NP you can run the test

they have created the script for testing

I'm going to use this one npm run

test watch

let me provide the pattern for song

controller

dopc now it is going to watch this spec

file you can see that test has failed

now

here have you included song service in

the

provider

no we no we did

not if I will add the song

service but still getting the error now

the song service is dependent on the

song

repository but we will include all these

dependencies in integration testing but

I want to test the individual components

so get rid of the song

service I got the error so we need a

fake implementation we got to create the

mo service for the

song Here is how you can

register a mock service with the help of

Mo

implementation you have to register the

song service and you going to provide

the song service

provider here you have to use the use

value property to create the fake

implementation object or the

service you will have the get songs

method inside the song service here I

created the mo function and it is going

to return the promise with this

record let's try to check it

out when I will open the song service

we H we will have these methods get song

is returning a promise get song is also

you have to write the fake

implementation or Mo implementation of

the song

service we

need

providers song

service

song

service here we have to write the fake

implementation get

songs you can create a mock

function all you need to do is return a

promise with a value let's

say ID is

[Music]

one title

title let me check the song

model or song entity we have one

property which

is

title dancing

feed now I

have the mock implementation of get

songs now you can write the test

case make sure you get the

service if you need I think I don't need

that you can see that now my test has

past now I'm going to write another test

case it

should it should fetch all the

songs

or you can wrap your code inside the

describe fetch all the

songs here I have to write this one or

you can say if you need to write

multiple test

cases for get songs functionality you

have to do it in this

block

now we have to call the

function

songs v

controller. get

songs it's going to call this method get

songs you have to use the async

keyword

now we have to write the

matcher it is going to give me the array

of the songs to

equal now we're going to copy this

one a test has passed now get

song should fetch all the

songs

now I'm going to

copy all of the code for mock

implementation for the methods of

controllers it should add the create

song dto it should have the update song

dto what we have done so far I created

the mo

function with Mo implementation remember

it is get it is getting the idea is an

argument now it's going to return the

promise here for the create song it is

accepting the create song

dto I create the ID which is a unique

key and I have separate the separate the

create Song D it's returning a promise

similarly we have done for the update

song we created the mock function with

an argument update song dto returning

the

promise in song service for the update

it is returning the update result so

make sure you have this affected one and

delete song what is an

error oh I have to restart

the

project

now we have a fake implementation of

delete

song now let's test this

[Music]

function get song by ID I'm going to

copy

that get song by

ID you can provide an ID which should be

anything get song Yes ID could be

anything or I I can provide

a unique

key a uu

ID you can see the test has pass now for

get song

ID now I'm going to copy the create song

Let's test

it we have created the new new song by

using Create song

dto we have to provide this create song

dto and song. title should be run away

because we are giving this argument here

create function is giving me the create

song dto with

ID or you can also write

another matcher to

equal ID should be a uu ID

ID and

title should

be

Runway run

away you can see that my test has passed

now similarly we have to do the same

thing for update

song we are creating the update song

dtoo by using the update song dto object

I would like to update the

title it should be defined and affected

should be

one update

song

you can see update song has passed

now now we have to

perform testing for delete

song I just provided the ID you can

provide any

ID you can see that delete song has also

passed now this is how you will test

your controller unit testing for

controller in this lesson we're going to

test our service we're going to write

unit test for

service when you run this service you

will get the same error because in this

song service we have a one dependency

which is repository the song Repository

we have these so repository will

have this we have to write the mo

implementation for find method find one

or fail save method and create method

update and the delete because our

service is using these methods from the

song repository so if you write the if

you run the test for song service. speec

you will get the same issue this is the

default implementation from nestjs

Project they are using the provider

right now we don't need any controller

here we are doing unit testing we are

doing individual testing for each

function let's run the song

service it is going to find the song

service. spc. TS

file the test has failed

now it is dependent on the song

repository but I did not provide here I

did not register it so we have to create

the fake or Mo implementation for song

Repository

what I'm going to do I'm going to copy

this code we

need

these get

repository and get

song I have created a two objects song

array song one song song and the song

array this is how you will create the mo

implementation for the repository we

have to get the repository

token here I can do

that one thing make sure you provide the

song service

I forgot to do that in the controller

Let's test

it so everything is working fine now now

we're going to test the

service we have to import it get

repository

token I'm telling to nestjs this is my

fake or Mo implementation for the

repository song

service for the find it is going to

return the array we use promise. resolve

Mo

implementation for the just I'm getting

the options as a find one options you

can import it from the type orm we also

need to

import create song

dto it is returning a promise with one

song it is going to return the promise

with a song newly created song and save

method is just a simple Mo function it's

not doing

anything in update we need to get update

song

dto we have return the mo

implementation and it is returning a

promise with one

song for the delete it is returning a

promise with

affected but maybe for the update you

can give this response affected

one now we have to test

it if you need a repo you can get the

repo yes we may need a repo I can get

the repository by using get repository

token let's

test the method from the song

service it should give me this song by

ID we're going to test this method this

[Music]

one this

one get song by ID this

one it is using find one or fail and is

using fetching the song on the based on

ID so what I have I have done I created

a new

song I I got the song on the based on ID

it should be Yu

ID Yu

ID so I'm going to spy on this find one

or fail

what I have

done I called this method get song in

under the

hood this Pi this method this Pi just Pi

will be spy on find one or fail it is

saying hey you have called find one or

fail from the original repository

method and it has been called with this

one this is how you can write the unit

test

now we're going to write the test

case to create song I created this

song and I'm going to expect it with one

song called one

time and you can say called with title

lover let's copy the

update let's copy the

delete everything is passed

now for update I think inside the song

service what we have done update

result so we have to fix

it more repository it should give me the

affected and the

one

result

result do affected equals

to

affected

one test has passed now if you want to

spy on delete method how many times I

have call delete method if you want to

track the calls you can spy on that by

using the Spy repository on delete

method I've have been called this one

time and it is affected one time I got

the it means affected means one record

has deleted

successfully and it has been called with

uid that's all for unit testing with

service

now you're going to learn the concept of

end to end testing we're going to do end

to end testing for our nextjs project

end to end testing is a software testing

methodology that focus on testing the

entire application flow from start to

finish now we're going to integrate all

the song controller repository song

service

everything you can do

API testing in end to endend

testing validation of the user flow

improved user

experience now we're going to start

doing the end to end testing first step

we have to add the script in our

package.json

file they have written the script for

end to endend testing but they did not

add add the

watch that's why I just addit the watch

or detect open handle

I I have written this line or keyword

for to handle the

errors if you will not at this line This

one this

word it will give you some type of

warning

messages the first step we have to

register it the type or a

module in the song and to end test here

we have the end to end

test this

one this is the end to endend test for

our generic application let's run

it npm run

test find the

script test E2

e and the watch

mode

let's provide the pattern

app it is going to run this spec file

this is end to endend testing for app

module going to create nests application

and initialize it here it is going to

test our root

URL under the hood they are using the

Super

Test request from the Super Test making

the API request by using calling the

server this is the end point and it is

expecting the 200 status

code test has

failed got expected 200 but got 4

44 but I would like to add the test

case into to end testing for our song

controller for song

module

let's create a new

file here inside the test I'm going to

name it to

songs I can call it

songs do E2

do- spec. DS file

it is just an initial code you can copy

that from the app do e2e

testing I got this

one describe it should be

songs import couple of

dependencies type or module

make sure you have created the database

for testing I created that with the test

F and syn synchronize set to true you

have to register entity manually it will

not work with regular

expression at the end of each or at the

end of all test when all the test will

be finished it is going to drop the

schema we will have the song Mar

is not getting the path I think

so we have to do in This

Way song Find song

entity same thing

here

there

is I got the testing

modu that's

it now we have to run

it here you have to provide

your

username

password and the Local Host Post Port in

the name of your

TP it is going to run this

file I got the error you your test Suite

must contain at least one test all right

now we're going to test the

code first

step after each test we have to clear

the repository because we're going to

interact with

database in the

describe this will be run before all and

we will have after each we have to clear

everything from the song table or song

repository this clear method will delete

the records from the table but it will

keep the schema schema

this function or this hook will run

after every

test make sure you import the super

test I'm going to write the test case

for

delete or not not a delete for

create

I just created a new method create song

we have the song song. title song.

repository and it is going to save the

song in the real database right now we

don't have more implementation for the

song repository or the song service it

is going to save the record in our real

database we are using the test

def if you don't have test def you can

create it

I have set the title get the repository

instance from the app.get and called the

safe

method maybe you need to

add a weight

expression because we are returning a

song

with

promise you can do in this

way it will automatically get this

promise with

song let's write the test

case before fetching these songs make

sure you have the record in the database

that is why that is why I created a new

song with create song first you got to

save the song in the in the postest

database with title

animals and then you have to send the

API request to this URL

doget and here I'm checking the status

code should be 200 and the request body

or the results body should have length

one which should be have one record it

is an array it is going to give me the

array in results. party and I'm I have

created a one song

so it should be there there should be

one song in our database so that's why I

converted into an

array after then when this test will be

completed it is going to call this

method clear the

repository you can see our test has

passed now if I write let's say 20 1 or

maybe 400 it is going to give me the

error hey I'm expecting

200 you can see I got the

error so get song endpoints has tested

successfully

now we're going to get test get song by

ID first we have to create a new song

then I have to I have to send the API

request make sure you have to send the

ID I created this song because after

each test it is going to clear the

repository it is going to delete all the

records from the songs

table create a

song then it's going to you have to

provide the ID first I have created the

song then we have to test it make sure

the body should equal to this

song I'm going to save the

application it should

pass two test has passed

now now we're going to test update songs

endpoint make sure you have to import

it it should be

it create a new

song and you have update song dto I

would like to update the animals to

wonderful sending the API

request this is how you will send the

data to if you want to send the Json op

object into the request body you can

call the send method I want to send it

as a update song

dto this one I want to update the title

which is wonderful status code should be

200 and affected should be one it means

our record has updated

successfully and

let's do this for

post

we have this is our create song dto we

did not

create we did not create the song right

now I'm going to use the create song dto

provide it as a request

body the status code should be 2011 and

the title should be

animals for test has passed now we have

to test the delete song

endpoint let's create the song first and

then we have to provide the ID which

record you want to

delete status should be

200 and the affected body should be

affected should be one it means record

has deleted

successfully this is how you will write

the end to endend or integration testing

with database or the nestjs

application nestjs version 10 has

released

now I'm going to show you how to create

new projects with nestjs version 10

version 10 is very fast they have

integrated the rest rust compiler they

have integrate the rest to compile the

source code

sjs if you Google the version 10 you

will find the blog post from the owner

of the

nestjs they have

released version 10 in the version

10 you you can compile the code in a

faster way like it will also improve the

hot

reloading you

can you can do development in the more

fast

way to start a project you have to add

this

command we we're going to use this

[Music]

options this one we will add these

options into Nest

CLI they have also introduced a new

feature this time you can Mo the entire

module instead of provider and

controller

these are all the new features in the

nestjs version 10 but the main feature

is improving the compile code speed of

the

compiler but let's create a new project

first of all you have

to

remove or uninstall nest

jli because you will have have the older

version of n

CLI I'm using Mac so we need to add the

sudo keyword instead of install first we

need to

uninstall the

nli I have already installed

nli can I check the version of this

package I don't know let's try to look

at that

I have

8.1.0 I have I have the latest version

but it will generate the nestjs 10

project Nest

new and we have to provide the name of

our project I can

say web

socket

implementation

nextest let's do it again nextest new

the name of the project

websocket

implementation I would like to use the

npm

it will take some time to install these

dependencies my project has

created I can look at by going to this

directory I would like to open this

project into my vs code

editor if you check the package. jsn

file you can see we have the nest

version

10 now what I have to

what I have to

do we have to compile the code

faster let's first we have to run the

project without this command This

One S swc Speedy web compiler first we

have to run it

without Speedy web

compiler

you can look at the time for running the

project when you will have multiple

modules you will have multiple

controllers and you added the testing

functionality your application speed

time will be slower your development

time will will be

slow so let's make it

faster with the help

of these two options I want you to add

these

options into package into

nli n c.

Json I'm going to add these two options

to my

compiler these two

options Builder I would like to use the

S swc and type

check let's run the

project you can see that I got the issue

fail to load fail to load s swc CLI and

S swc core we got to install these two

packages let me execute this

[Music]

command install it as a def dependency

because I want to improve the project

running

time increase the

development

time

so packages have

installed now we need to run the

project now it can take the S

swc it can use this Builder and type

check our project is running

the project running time has increased

now if I save something in our

application let's

say in the app

controller in the app

[Music]

service

hello world from nestjs version 10 I

want to save the

application successfully

compiled this is how this is how you can

improve this implement or in improve the

development time the project running

time in development

environment in this module we're going

to work with web

sockets when you want to implement real

to real time application like chat web

application real time web

analytics live streaming online gaming

then you need web

socket which we have worked with HTTP

server in

HTTP where client sends the request in

the server

response but if you if you're using web

sockets web sockets establish a

persistent connection between client and

the

server and you can have ongoing

communication the best example is

Facebook Messenger you send a message to

your friend and your friend rep replies

and you reply to your friend and your

friend reply this is how the bir

directional communication Works in under

the hood they have implemented the

websocket protocol they are using the

websocket

technology if you need to make

persistant connection then you need

websocket you want to implement a

realtime feature like live updates live

score live streaming then you need

websocket

here is chat application can be built

with web socket collaborative editing

tools real time analytics online gaming

and the live streaming nestjs also

provides websocket module you can use

that but it also provide two approaches

you want to do you want to work with

socket iio or you want to use the web

socket you can get the details from

their official

documentation but in this video I'm

going to implement the socket

IO you got to install these two

packages I'm going to open my

package.json file let me add my

dependencies I think I already installed

these two dependencies I don't need to

do it again you can do it manually by

running npm install and first install

this

dependency and then you have have to

install these

dependencies our next step is to create

the events module we will have the

Gateway a Gateway will be responsible

for handling the events you will have

the events module a Gateway is nothing

more it's a class with provider you can

inject it as a

provider here we we need this Gateway

we're going to create the event Gateway

it's nothing more it's a class

here you have to decorate with websocket

Gateway I'm allowing any origin you can

use any specific origin if you

want here I'm trying to implement the

own module in

it when any client connected to my

application this event will be

triggered this is how you will register

the event by using the own own

function I can also get the socket ID I

can also log that have has it connected

or

not this is how you will create or

register a new event subscribe message

and we will have a function new message

you will have the message body you will

get the

data if someone sends message or filed

an event from the client side

application like react angular view or

any kind of front- end

application this function will be called

but make sure they have called this

event with message key this key and it

is going to lock the data you can read

this text here for every

detail let's create events

module

we have created the events module now

let's create the

Gateway you can see we have the events

module Gateway will be registered as a

provider you can see in the events

module we have websocket Gateway by

using this decorator and we have one

event if you want you can add the

CES and we also need to establish a

connection I need to check make sure you

imported server from socket IO

Library you have to import it manually

otherwise it will not

work websocket G websocket

server now we have this handle

message subscribe

message when you need to register an

event in backend application or the

nestjs application you will use the

Subscribe message

decorator

and what I would like to do I want to

get the data or you can have client but

I like the data I don't have any payload

option but I'll use the message body

decorator instead of use this one

message

body data should be type

any I'm not going to return any thing

right now all I want to log the

message I can say message received from

the

client and this is my

message or I can log the

data so far we have registered the event

when any web application like any

front-end application has connected to

our websocket server

first they need to connect on the our

host here we have provided but right now

we're going to run the project on Local

Host so any front end application should

connect with Local Host colon 3000 and

then he can establish a connection

between with with this application when

when any front end application establish

the connection it's going to call the

own module in it but right now I don't

have any own module in it right now it

will log

this

message

implements on module in it that's it

after module loaded or this file is this

class is loaded successfully then we can

log the

message when connection established this

event will be triggered and it is going

to call with socket I ID and the

connected its Boolean

value now we have set of the websocket

server and we created our first event

which is message you can have multiple

events here you can also perform the DB

operation like if someone sends a

message you can save the message into

database in the next video in the next

lesson we're going to consume this event

from our frontend application we will

have a simple basic front end

application with index.html and there

would be JavaScript in the index.html

file now it's time to consume the

application consume the event or send

message from the frontend application

when you run your server let's say npm

Run start

def now my server is it's ready to

listen this message event it's waiting

for someone to send a message by using

this event

key so all you need to do you got to

create a

basic

index.html file you can copy that code

or you can create manually I can say

client here I will have

index.html file one more thing you will

see events Gateway subscribed to the

message event to this

message so it means we successfully

created the event I'm going to copy the

code I'm using the socket IO Library

where we are creating the socket IO

instance by providing our application

path in our case we have nest's

application is running on Port

3000 we have registered a event

it's trying to connect with our

application with nestjs application when

it when it will be connected it is going

to log this message and emit this

message to the server here I'm going to

open the

server this one events

Gateway we have registered the message

event this is how you can emit the event

I'm telling to socket IO please call

this function that's it and we also

registered couple of events if someone

if if server sends data back to the

client we have to register it we have to

catch the data here that's why I use the

on

listener if exception event trigger it

is going to call this method if if our

backend application disconnected or

stopped it is going to call this event

it is going to trigger this event now we

right now we're not returning anything

here let's try to test

it uh I'm going to use open Live server

go live when you open the index.html you

will

see this it is going to open my project

into live server please check the

console for message

reply inside the console you will

see you have connected

successfully when you open your backend

application this message is received

from the

client so client has sent this message

or you can

say I am the

client I'm going to reload the

application it has automatically reload

reloaded you can see I'm the client

so it has also connected one more thing

you will also see this socket ID and it

has it means connected successfully

first it is going to log this message

console. ID Lo connected we have emitted

this message event it's going to call

this

function now we we are not returning

anything that's why this event is not

triggered let's try to return from

return something I'm going to return

some value let's

say some value from server let's see

what will

happen our application

reloaded let's try to test it out

message received from the

client but I did not log what message

have you received

you can see message received from the

client on the client side we sent this

message I'm the client it has

received but it is not triggering this

event I cannot see anything here let's

say if I if I'll try to log

something

hello I cannot see this Hello message in

my

console it's not

triggering so that is why you need

observable websocket also provides the

observable you can

say I would like to return this

observable

websocket response and I can have any

type here we have

to convert the object to observable

that's why I'm going to use the off

operator from

rxjs I can say

event you got to provide the name of the

event which is message and the

data here you can return anything from

the server

message

returned from

server

hello you should see this message here

because we are listening on the client

side you can see event message received

from the server if I will refresh our

application you will

see this

one message returned from the server

hello if I stopped my application it is

going to F this or trigger this

disconnect event you should see the

disconnected this is how you will create

wi directional or realtime chat

application with web

socket in this lesson I'm going to teach

you how to set up graphql server we're

going to use Apollo server nestjs Apollo

package nestjs graphql package graphql

and TS

Mor you can read the documentation of

these

packages I'm assuming you must know the

basics of graph ql I'm not going to

teach you the basics of graphql what is

graphql and why do we need graph Q

I have attached a started kit project

you have to open it and run npm

install I have already I have already

installed all these dependencies I don't

need to install them

again all I need to do is to install

graphql packages I'm going to copy all

of these

packages

the packages have installed

successfully and now the next step we

have to register the graphql

module I'm going to open my app

module and we I would like to import

graph module

here we need to import couple of

dependencies Apollo driver config

I'm telling graphql hey I want to use

Apollo

driver and I will have do graphql

file where I will place all my schema

definitions in the graphql

file this file will have the typescript

typings of

graphql and output as a class don't

worry I'll Teach You How can you

generate the typings

we are using for RO to register the

graphql

module the Apollo driver config specify

the type of the configuration options

being

provided so driver AP poo driver this

property sets the driver used by the

graphql module in this case we are

telling graph Nest chairs hey I want to

use a polo

driver

we will place all of our graphql schema

in graphql file the extension should be

do

graphql uh if you want to generate

typescript definition from your graphql

schema you have to specify these

definitions I'll teach you how to do

that and we are just combining the

path we will have so graph. TS file

inside the source

directory this property specified that

the generated type script definition

should be outputed as a class this means

that the generated code will be

representing represent the types as

typescript

classes now our next step is to create a

schema

file

inside the song folder I'm going to

create a new file song.

graphql here I will place all of my

schema file we're going to have a

query let's define a song

type we will have ID and the type of ID

is required this means it is a required

property it should not be

null and I'm going to add a string

variable or string type field which is

title the type of the title is string

and I'm also going to add a new query

type here I can say I want to fetch all

the

songs and you can say the type should be

song and it is going to return all the

songs our next step is to generate the

typings which is typescript definition

file

we need a graphql definition

Factory

class here we are trying to in we are

instantiating or creating a new object

from graph definition Factory there is a

generate method to generate the typing

you have to specify the type which is

I'm using the regular expression here I

will have all of my schema file in the

cql that's why I use the type definition

path and I would like to I would like to

create all the type typescript

definition in the graphql dots file it

will save it as a class let's create a

new

file generate typings dots file inside

the root

directory typings

dots

now all you need to do is to execute

this

command NPS npx DS node generate

typings it is going to generate the

graphql dots file with this

definition you can see that a graphql

dots file has

created we have a class which is song

and we have a abstract type which is I

query and we have this

type so we will use this type definition

when we will creating disolver functions

when we will resolve queries against

your schema

files now I would like to run the

application is everything fine now let's

test it

my application is running

now let's send the request to Local Host

colon

3000 and you will have playground at

this graph quel

Endo when you go to the Local Host colon

3000 you will see the playground this is

how you will perform

graphql apis you will test graphql apis

by using this

playground let's

say I'm going to send the API request

graphical API request I want to fetch

all the songs I want to see the ID and

the title but it is going to give me the

error hey you don't you are not

resolving this

query because it's returning

n it's getting the validation eror

because we don't have any resolver to

resolve this query this

one in the next video I'll teach you how

to create mutations and how to create

queries we're going to we're going to

fill our song

schema let's complete our

schema let's create a new

query to fetch a single

song when you try to fetch a single song

you must need to provide the ID so ID

should not be

null and it should return this

song in the

response let's write a new

query it should give me the

song and I would like to fetch the the

song on the based on

id id should not be

null now we're going to write uh venue

query in the playground you got to

follow the structure song and you have

to provide the ID in this case I'm

providing the 1 2 3 as an

ID now we're going to Define mutations

we learned how to fetch data with the

help of query but I want to write the

data so to to mutate the data you need a

mutation so let's define an mut

mutation

mutation I'm going to have create

song it will accept the create song

input

or create song

input and I don't have any type so

that's why I'm going to define the

input create song

input I will have the title field and

the type should be string it should not

be null so I can say the type of create

song

input it should be create song input and

it should not be null and it should give

me the song in the

response

now I want to write the mutation for

delete song or you can say update

song I would like to update the song

Only the based on ID the first argument

it should be ID and the update song

input we will have update song

input it should give me the update

result this is not an empty

field that's why I use this exclamation

mark and

input

update song

input title should be string but I did

not mention it to required property if

you will have multiple song multiple

fields in song let's say a user will

have let's say a song can have

date or you can

say date release date or publish date or

artist something like that but I cannot

set date required in the artist required

field because it depends on the user a

user can update the title or whatever he

wants to upate

update now I don't have any type for

update

result let's define a new type update

result it will have

affected and type should be

number do we have int yes

int similarly we will have a type for

delete

result delete

result and typ should be int now we're

going to Define mutation for delete

song I can delete on the based on

ID here I can say delete

song I don't need to put anything and it

should give me the delete result that's

it so we did not resolve these queries

in mutations in the next video we're

going to write resolver functions to

resolve these query and mutations Let's

test it out by generating the

type one more thing I want to show you

can create a script to run the typings I

can say in the package.json

file let's define a new

script we here you need to define the

script generate slash colon typings TS

node generate typings this njs project

all already installed TS node as a def

dependency you don't need to install it

again npm

run I can say generate

typings it will generate the typings or

types in the graphql dots

file

I found an

error unknown type create song input did

you mean create song input or update

song

input oops I have to fix

that everything is fine now let me see

my graphql dots file we have type for

create song input type for update song

input we have types for mutations and

update result and delete

result when you see your

playground you have to look at the

queries in mutations we have queries and

mutation when you try to

fetch let's say I want a query for

songs ID let's say I'm going to provide

invalid

ID let's try to fetch the title and the

ID I'm going to send the request it

should give me the error hey you are not

resolving that's why we need resolver I

can use n CLI to generate a new resolver

I can say

song it's going to create a new resolver

resolver is nothing more it's a provider

like a service you can inject it as a

dependency here you can see

that inside the providers we have a song

resolver and it is it also created the

song resolver dopc file and song

resolver we have resolver

Tator now I'm going to resolve these

queries I'm going to open song do

graphql let's resolve this

query I also need song

service so Constructor

private song service song

service let's import

it

I have this I need a query

decorator here I would like to resolve

this query

songs I can say get

[Music]

songs return this

do song service dot get songs

and you can also mention your return

type I can get it from the song entity

or song graphql type this

one make sure you are using the Asing

here what is saying unable to resolve

the signature of method decorator when

called as an

expression

oh we need to get the query from nestjs

Craft

ql now it looks

good let's try to test it

out let's try to resolve this query

I would like to fetch all the

songs you can see

that we have a song I already created a

song If you don't want to see the title

you can say I only want to see the

ID but I have single song in my

database now let's resolve the query to

fetch a sing single song I Can Say

song

async Get

song it should give me the song with

promise this do song service

dot get

song you need to provide the ID but I

can get the ID

here

I can use the arcs from the N graphql I

can say the

id id is

string let's provide the ID

here I have saved my

application let's try to resolve this

query I want to copy this

ID and let's fetch a

song ID should be this one and I'm

expecting the title in the response fail

to fetch please check your connection I

think my application did not start it

now I have to send the request I got my

record which is song on the based on ID

if I provide the invalid ID let's

say you will see the error invalid input

Syntax for the type

the ID does not exist as same

here now I'm going to provide the

correct ID I got the

record you have learned how to resolve

queries in the next video I'll teach you

how to resolve

mutations now you're going to learn how

to resolve mutations in the previous

video we resolved our queries let's

resolve

these mutations create song update song

and delete

song now you need mutation instead of

query we also need create song dto as An

arcs or you can say create song

input you can also do that you can also

get this typing from from graphql

file and I just called this

function it's not finding source. cql we

have to do it

manually now it looks

good

it is taking some time to in restart the

server let's create a new

song I'm going to write mutation create

song create song input we have to

provide

title the name of the song which is

follow me

I want to see ID and title in the

response you can see a new song has

created I can fetch all the songs and

you can see follow

me it means we successfully created this

we have successfully resolved this

create song

mutation now it's time to resolve update

song

mutation I'm going to copy this

[Music]

one update song we need to Res solve we

need to get update song

input update song

dto or you can use update song input

from graphql file I also need to get

update result from

graphql it is

saying I'm getting the

error

update

song If I get this

from from typ orm let's see what will

happen now it looks

good because this start update

song it's returning the update result

from type

orm when you look at the update song you

will see the Promise with update result

I imported update result from

typm let's try to update the

song I'm going to write

mutation update song we need the

ID I'm going to copy this

ID let's place it

here and we we also need to provide

update song

input I would like to update the title

update

song Let's fetch all the songs and you

can see the updated

song similarly we need delete mutation

let's resolve it I'm going to copy it

here delete song we have to get it from

the type orm

let's try to delete this song

mutation delete

song we need to provide the ID I'm going

to copy this

ID let's see

affected delete

song successfully executed it should

delete the song

let's try to fetch the song on the based

on this

ID you will see there is no song here

you can see there is no

song in this lesson I'm going to teach

you how to handle errors in

graphql let's say I want to fetch all

the songs but instead of returning all

the songs I have to return the

error you can do simp simply by using

throwing the error or you can say let me

do this in this way I'm going to comment

this line through new

error I can say unable to fetch

songs let's try to send the graphical

request it's still

working my application did not reload

yet let's wait

now it has

reloaded you can see unable to fetch the

songs I got the error internal server

error uh if you check the Apollo

documentation we are using Apollo driver

Apollo driver is saying you can use the

graphql error class and you can provide

your own

message Apollo Apollo Apollo

documentation is saying

they also provide buil-in error codes

like Parts field graphql validation

field Pat user

input bad request we're going to use

this error bad

request all you need to do is to throw

the error and you going to provide your

message in the code so let's use the

throw the

error new graphql error

I got this graphql error class from

graphql package here you can see that

now first I have to say unable to fetch

the

songs you have to provide the options

you can provide the

code you can say server error or what

what type of message you want to use it

depends on your use

case

I can say internal server

error let's try to test it out I saved

the

application it will take some time to in

reload the

[Music]

application application has reloaded

let's send the request and I got the

error unable to f F the songs and I got

internal server error this time you can

see graphql error unable to fetch the

songs you can also see the message I got

the error at song resolver doget songs

you can also check the error

stack get song song song resolver doget

song we have the error at this function

get songs this is how you can send the

error in

graphql

if you want to use your own custom

message you can also do that you can

provide your custom message your custom

code and your custom

extension you can also set the HTTP

status if you're working with HTTP API

you can also set your HTTP status code

and some type of

headers in this module you're going to

learn how to apply authentication in

graphic

SQL we have implemented authentication

with rest

API now I would like to implement

authenticate graph cuel

apis in the previous module you learned

how to create graphel apis with

nestjs I'm going to pick the same

example project just like we did with

authentication in rest API

I have provided the starter kit code you

have to open it and run npm

install when you install all these

dependencies you can run the project and

you will get this

error let me run the

project because there is no graphql file

there is no graphql extension file

when you open the app

module you will see the graphql

setup we have a graphql module I'm

creating a graphql module by using the

Apollo driver just like we did with in

the previous module I'm using the

context I'm just returning a simple

request mapping the request into request

it's nothing more I'll teach you more

about when we will protect

resolvers so I've already taught you all

of these stuff like we created the OD

service we have a login

method here we have a JWT guard I taught

you how can you do that what type of

implementation we have done we have

passport strategy with JWT it's

validating the

user and we have dto login dto

everything

everything I have taught to

you if you don't know about all of these

functionalities you can go back to the

module number six on

authentication you can watch the first

four lessons on authentication or first

three lessons on authenticating nestjs

apis you will get the

error no definition found no type

definition word found because we don't

have any graphql file I just did the

graphql setup first of all we're going

to set up our we're going to define the

schema we don't have we don't have any

schema what I want to do I want to do

schema in O folder let's create o.

graphql what we are going to do we're

going to create the user type and we're

going to Define query

and we will have mutation for sign up

mutation and we will have login

mutation first of all let's define a

user

type the first argument is ID it should

be required not null first name the type

should be

string I can get this value from the

user entity

you can open the user entity on the

right hand side right

side first name is required last name is

also

required and email is also

required and password is also required

so we need these properties these five

properties I'm not going to play around

with playlist something like

that let's make it more simple we

defined a user

type now I'm going to define a

mutation sign

up it is going to take the signup input

and the type should be signup input we

did not create it

yet it should be required and it is

going to turn a user back in the

response or sign up

response we not we did not create this

we did not create this signup response

type now let's define a new type with

signup

input when you when you sign up we are

telling you need to provide hey client

you need to provide the first name you

need to provide the last name you need

to provide the

email email is also required password is

also

required now let's define the sign up

response sign up

response what you want to send in this

signup response you can send a simple

email it depends on you I'm going to

send a simple email

now we're going to Define

query we have a mutation let's

define login

query I can say

login it is going to take login

input inside the login

input and it is going to return a login

response we did not not have these type

yet it's are

required let's define an

input I'm going to Define input here

login

input we need

email type should be string we need

password type should be

string and we also need to Define login

resp

response I want to send the access token

you can double check it from your OD

service or user service we have a login

in the login we are just returning the

access token here you can see that

access token the type is string we're

going to follow the same convention the

type is string it should be

required we created the login mutation

that that's

it let's try to test it out by running

the mutation or running the typing

command npm run

generate

[Music]

typings it is going to generate the

typescript definition

file typescript definition file has

created you can see graphql do s

file we have all of these

typings we have created or defined our

schema in the next video I'll teach you

how to resolve queries and mutation

we're going to work on sign up mutation

first in the previous video we have

created this sign up

mutation now we need to resolve this

signup

mutation we don't have resolver inside

the O module let's create a new

resolver we have to provide the name

which is

O Au resolver has created you can check

inside the Au

module we have Au resolver we have spec

file and we have Au

resolver we have to resolve our signup

[Music]

mutation

mutation which is sign up I'm going to

open the autra ql

here I want you to do it should be sign

up

user I'm going to define a new function

and it is going to return a sign up

response you can get the

typing from graphql dots

file and one more thing we need to

inject

service user service and OD service we

need both of

them user service and we need OD

service we have a create

method let's get the argument I can use

the

arcs we need to get sign up

input and I can say sign up

input you can also also get the type

sign up

input and I'm going to provide sign up

input everything is fine now let's try

to test this signup

mutation I'm going to run my

application my application has started

and I got the

error

sign up defined in resolver but not in

the

schema oops there is a type typo Here

sign

up we have to generate the typing

again npm run generate

[Music]

typings

everything is up to

date it is taking too much time because

I'm using no nestjs Version 9 because I

built this project in module number six

by using the nestjs version 9 that is

why it's very slow

I have to oh let's restart it

again my application has

started I'm going to send request to the

Local Host callon 3000 and/

graphql if you check the docs we have a

sign up

mutation let's create a new

user first name make sure you have

database in your

postgress let's provide the last

name let's provide the

email let's provide the

password I got the

error because I did did not select any

field here I would like to select the

email because I can only access the

email I think I already created a

user with

this email let's use new

one there is an

issue reading

password

let's try to check the

error password

is

invalid

why let's try to log sign up input what

it is

getting

or do we have sign up function

here inside the OD service do no we got

to use

the user service.

create let me check in the Au controller

what we are calling what we are

using user service. create that is

it I'm getting the

undefined maybe there is an issue

in autra Q let's check it

out oh syn sying up

input my God sign up

input sync

input sign up

input let's run the project let's update

the fix it sign up input we also need to

update it here sign up

input

run the

project Let's test it out by sending the

request to create a new

user sign up input we also need to

update

that

we have created a new

user a user has created

successfully you can see that we got the

object let's log in I want you to

implement it I'm going to copy

that we need to get the

query from nestjs graphql

package we also need to get login input

and the login

response we have a typo here

aouc I need to run the typing

again

let's run the

project let's try to send the login

request I'm going to copy use email and

the

password I need to get the access

token we have successfully logged

in because I got the access

token in the next video I'll teach you

how to protect

resolver we're going to create a new

protected field which is

profile only authenticate user can

access this

profile we have created all

card this one JWT o card we have to use

this o card into our resolver I'll teach

you how to do that but I want you to

think about how can we implement or how

can we apply JWT off

card we have completed the sign up

and the login

functionality let's say I want to

protect

resolvers when we were building the rest

apis if you look at the app

controller I can say this is the

protected route only authenticated user

can access the

profile and here we also getting the

user from the request

object but you are thinking about how

can we protect the resolver let's say I

want to write a query

profile and type should be profile we

don't have any profile type let's create

the profile

type the type should be string the field

should be

string and here we have the user

ID let's generate the

typing when we resolve this

query only authenticated user can access

this

profile we should not allow anyone to

see other person or other people

profile how can you do

it when we were building the rest apis

we use the JWT

guard we have created this guard and we

apply when we applied this JWT o card on

our protected route just like we did in

the app

controller this is my protected route

the profile route and I have applied the

O card by using the use card JWT oard

maybe you thinking how can we do into

graph

well I'm telling you I'm you you also

need God you also need JWT o guard I

want you to implement it you don't need

to change anything in the JWT strategy

because we were using the passport

strategy if you are not sure if you

don't know about how did I implement the

passport

strategy you can look up the

Authentication section I think it's

section number six or module number six

or

seven and then you can get the

lesson for passport or jwd

authentication it has generated the

typings in the graphql dots we have the

profile

class now when we resolve this query I

have to say hey this is protected

route let's let me show you I'm going to

run the

project to access the protected

route a user or client should or client

must need to provide authentication

token the user can get authentication

token by executing or sending the login

request

and this login request gives the access

token in the

response let's wait for the

application my application is running

now let's send the request to the Local

Host col 3000

/ql here you can provide the

authorization HTTP

header I'm going to send the login

request I got the access

token here you can access the profile

route you have to provide the token

here we did not write the resolver for

the profile

query let's resolve

it inside the Au

resolver let's resolve Au query or

profile

query get

profile it is going to give

the

promise

with

profile and here is the

question

how can you access the profile or how

can you access the current logged in

user like we need to send current logged

in user

actually we need to send the user ID the

current logged in user

ID and his

email we are returning the

promise that is why I caught this

issue let's return new

promise and

resolve return

resolve this

object I just created the fake

promise to pass this

test oh I have written the profile in

the

mutation let's change it to

query restart the

[Music]

application now we're going to send the

request it's still

running now we're going to access the

profile I caught the profile

but only authenticated user can access

this

profile so we need to apply the O guard

how can you do it let's create a new

guard I'm going to copy that guard and

create a new guard and I'm going to say

gql

oards

here instead of JWT I can say graph o

card and now we need to do a little bit

logic we need to use the can activate

function because in graph ql we need to

get the execution

context and we need handle request it is

going to

return a

user and you can import authentication

error when you look when you look at app

module you will see this

request I'm just mapping

the request from req request here I got

the request from the context here you

can see

that and I call the super Constructor by

calling this execution context

host because in graphel you need to get

the request object from the

context when you have if you have worked

with graphql before each resolver will

have four argument

here you will have for

argument

parent I think

root context value and info you can get

the documentation from

Apollo server

resolver here you can see

each resolver has four arguments parent

ARS context value and

info ARS you can see

ARs and I'm going to log

everything

parent console. log ARS

console. log context

value and we also need to log the info

let's see what is inside this this stuff

but make sure you apply the

guard use guards I can say graphql or

guard now this route this resolver is

protected it is secure

now don't worry I'll teach you

everything what is going on

here let's send the

request

here you can see the log

console there are a lot of stuff

here parent is undefined there is no

parent for this query ARS is an object

but is but there is nothing inside the

ARs there's a context value this is

there is the request

object and inside the request object you

can find your

user here is the user I found the

user this is

the this is the

user this is the this object is current

logged in user

if you look at the jwd passport

strategy here we are

saving user ID and the

email that's why I got the user ID and

email what I can

say I can only

return context

value do request.

user

I don't need to use the promise

here it's just returning a simple

profile I'm going to send the request

this time I got the original user ID and

the email let's sign up up a new

user I'm going to create a new

user

Linda let's save the

email now I got the user we have

successfully sign up let's log

in I got the access

token now I can use this access token

here I want to access the profile of

this route or user wants to see this his

profile I got this

user now let's debug the application I'm

going to put couple of break points here

what is going on here let's look

at I have already set up the VS code

folder inside you have launch. Json file

if you don't know how to debug the

application let me teach you I've

already taught you there is a script in

the package. s file for the debug the

application you can

say npm

start please start the project in debug

mode my application is running in the

debug

mode

now I can start the debugging by

pressing on this attach

button I've put couple of break points

here now it has

started I can debug my applic

a I can also put breako

here or

here now we're going to send the

request it has stopped at this o

card and first of all it is going to run

the can activate function we are using

getting the graphql

context by calling the

create and here I got the context

object and inside the context you can

see we have the Handler function we have

the

ARs ARS

property the first one is object and we

have a request we have this request and

we have field name which is

graphql field which is

profile you you can see the field

noes this is how graph run under the

H this is my string or the query graph

request and here is the name something

like that profile which is

profile let's step over the code you

will see the

context inside the context we have OD

context type

graphql now I'm extracting the request

object by calling the get

context so I got the

request inside the

request you can see

that this is the request we have this

endpoint SLG graph

ql this is the body we have the

query and we have the

variables let's jump to the next break

point there is no

error and there is a user you can see

that and it is going to return the

user now you can access the user

inside the

context parent is null which is

undefined we don't have anything in the

ARs now you have the context value you

can also do debugging here context value

dot request.

user you can see I got the

user and we have the info

info is related to information related

to query if you need to access the path

parent type field name something like

that

schema then you can use the info

validation error we have directives

include skip

deicated query type graphical object

type we have the fields login

profile all this information related to

graphql schema and the query inside the

info

object now we are going to just return

the current logged in

user that's how the authentication Works

under the hood in

graphql if you need to implement

realtime application you have to build a

realtime functionality like chat

application or notification type

application

then you use graphql subscription if you

have worked with API rest

apis we used websocket and socket iio

for realtime

application but we are building graph

apis if you need realtime functionality

then you need graphql

subscription I'm going to build or

Implement graphql subscriptions with

nestjs Pro project first of all you have

to install dependency graphql

subscriptions and then we will install

the subscription

Handler just like query and mutation you

need to define a new type

subscription I have created this song

created field it means when a new song

is published to Spotify

application this Spotify application

will send the notification to all users

we want to implement this

feature when you define the type

subscription we defined it

here you have to write the resolver to

resolve this field we need a pops up

module from graphql subscriptions the

package we have installed

earlier here it is going to listen

for song created event this

resolver is listen for song created

event here we are resolving this field

song

created when you run the application you

should go to the Local Host colon 3000

/g

graphql I'm going to run the

subscription song created we have ID

title I have started the subscription

you will see the subscription is

listening it's in the listening mode our

next step is to publish this

event when we will publish the event you

have to send the payload which is a new

song and I have created a new song Here

we are publishing an

event

here it is going

to now the subscription is already

running here you can see and now it can

receive it has received a new

song if you want implement this

subscription you can do

it otherwise you can follow me I'm going

to implement it you have to install

package graphql

subscription and we have to install the

Handler in the app

module install subscription Handler

let's define a new type subscription in

the song

graphql I'm going to Define It Here song

created it is going to return a new

song now we need to resolve it

resolve the song created field inside

the song

resolver we need to import psup at the

top of our

resolver you can import it from graphql

subscriptions

package now we're going to resolve this

subscription song

created I can do it here at the

bottom we need to get

subscription from nestjs graphql

package let's try to import manually

from cql

subscriptions we need pups

up

let me run the application and then I

will be able to start the subscription

in the listening mode the pups sub Asing

iterator we are telling to pups sub

module or the ppup module is saying I'm

listening for the song created event

with this label this is an event I'm

listening for an event with this label

song

created my application is running

now let's run the

subscription when you check the docs you

will see subscription with song

created I'm going to start the

subscription song created when a new

song will be published it is going to

give me this record the song object now

it is in the listening

mode

when we will

create a new

song it means when artist in real world

Spotify application has published a new

song Spotify application will send the

notification of this song to all

users new song I can say new

song

I need to get ID and the

title a new song has created but I

cannot see anything here because we did

not publish the event when we will

create when we will be creating a new

song Here we have to

publish this event this one song creat

event so you can do it as well I'm going

to copy my

code and let's do it

here this is how you

can sent message to the event by using

the song created label and we have

provided the payload make sure you use

the song

created Property name otherwise it will

not not

work let's create a new

song I have created a new song and it is

saying I cannot could not connect to

websocket

endpoint please check if the endpoint

URL is

correct now it's in the listening mode

mod created a new song now I have got a

new

song because we are publishing a new

song and it has received it

here let's say I can say new the name of

the

song you can choose any

name I have created a new song or artist

has published a new song at Spotify web

application now the Spotify application

has has sent the notification to all

users who are subscribing to song

created

event that's it the concept of

subscription in this module you're going

to learn how to test graph

apis we have already tested our rest

apis we're going to use the same logic

to test graphql

apis we're going to do Mocking the same

way just we did in the previous

module when you see song resolver dopc

file you will see this default

code when you run the test by using this

command npm run test you will get this

error hey you are using a song resolver

but your song resolver is dependent on

song

service you have to import it but we are

doing unit testing so when you are doing

unit testing you have to test individual

parts of your code you have to test

individual

functions if this function is depend

dependent on some other functions or

some other dependency or some other

classes or some other services you will

create a Moog implementation of the

dependency I've already taught you the

Moog implementation when we will when we

will be testing song

controller this is how you will create

the mo implementation of song

service you we will have have these

methods inside the song

service in get song create song we are

just creating the mo

implementation I just copied this code

from the song Ser song controller song

controller spec file and I have updated

the create song dto to create song input

and update song dto to update song

input and then you will test your

functions

if you want to test your get fet song

Get song function inside the song

resolver you can do

that I'm applying the await expression

on get song and I got the song here I'm

doing

expectation checking asserting or

expecting value it will pass this is how

you will test create

song create song will be passed update

song and the delete

song Let's execute it or you want to

execute by yourself I want you to do

it let's select the song

resolver it's going to run the song

resolver dopc

file

you can see the

error hey your resolver is dependent on

the song service but you did not import

the song service let's fix it by mocking

the

service I'm going to copy the same

code

and paste paste it

here we don't have song service let's

import

it

it's not giving me the suggestion I have

to import

manually I got the song service we also

need to get the create song input and

update song

input

I think it will not get this path Source

do/ graphql

let's add the complete

path you can see our test has passed

now

now we're going to write the test unit

test for a song's

query it should fetch a song first of

all I need to apply a weight expression

on get songs it is going to give

me this song because we are using our Mo

implementation inside the get songs it

is going to return this object or this

array with a promise here we are just

resolving

it unable to fetch songs I got the

error let me check my song resolver what

is inside the song

resolver I think I'm throwing the error

that's why I got this error let's

comment this code and I would like to

return this song

service with get songs array it is going

to give me the array of the songs we are

just

using this get song method

but we are using this

implementation this one it will call the

get songs but it is it will use our own

implementation this

one this is how you can fix the bugs

with the help of unit

testing

our test has

passed now we need to test a single song

query we have created this

song actually we need to yeah we need to

test this one we need to create test

create new song

resolver we're just creating a new song

and we are expecting

it because create song will give me the

ID and whatever we

passed

here the object it is going to return

the same object

here

the test has passed now we need to test

update and

delete it is giving me the error update

song a unique

ID we are not expecting the ID in the

update

song there is an issue I

think it is going to give me the

ID

let's look at the update song

[Music]

resolver song

resolver let's look at the update

song update

song

I think I have to change the order first

I need to get the ID I need to place the

ID and then I need to get the update

song input you have to rearrange the

order now it should

work

let me look at the song

service ID it's giving you are not using

the update song

tto title

but let's restart the application

the error is gone

now everything is fine our update test

has passed and our delet delete the song

test has also

passed it is returning the affected

that's why I use the affected

here in the next video I'll teach you

how to do end to end

testing graphql

apis this lesson I'm going to teach you

how to do end to endend testing with

graphql apis in the previous lecture we

tested unit tested we tested the

individual function of resolver now

we're going to do integration or end to

endend testing we're going to test

exactly the API by sending the HTTP

request or queries from the HTTP

module this is how you will test the

songs

query and it is going to give me the

result I'm using the

request request package to send the HTTP

request if you are working with graphql

there is only single endpoint which is/

graphql it will be same for each query

and

mutation now I'm trying to fetch all the

songs and I got all the songs this is

how you will test the end to end testing

I already taught you how to set up the

end to end testing

file when we were building when we were

testing the rest API in the previous

previous

module so

before each we're going to create

testing module this is a

same before

all we're going to

create new database I have the test

database it will drop after completed

all the

test and after each we're going to

delete everything after each test we're

going to delete everything from the

songs table that's why I'm using the

songs Repository do clear method and

after all we're going to stop the

application we're going to use this

method to test it's a helper function to

perform our testing nothing more it's

just creating a new

song and this is how you can test a root

end point it means our testing is

working fine let's implement

it there is no script for end to end

testing for the we have an end to end

test but I'm looking for a watch mode

testing that's why I'm going to add a

new script it will run end to endend

testing in the watch

mode let me run the end to end

test in the watch

mode it should be e to

e e to

e right now we have only a single file

which is AB

do E2 e-pack

dojon if you run this file let's say

app it is going to run this

file I'm going to copy this source

code and let's create a new file inside

the test

folder we will use this test folder for

in to end

testing let's define a new file

song SL do E2

e-. I have copied the source

code

this is the default

code we need to add a type orm setting

before all the

test we need to create a new

database let's run it here

we need to import couple of

modules we need a song module and

song entity let's get

it type Ork

module we also need to import type or

module actually I'm going to copy

everything and paste it

here now we have before

all we also

need let's

define it should be song

resolver end to end

test we need after all and after

each after each test you need to clear

the songs table and after all the test

you have to close the

application

I'm also going to use this helper

function I already taught you these

Basics when we were building when we

were testing the rest

apis that's it our setup is complete

now let's run the

test this time I would like to run songs

file

let's try to run the song file song. E2

e-pack our test has passed now and you

can see this test is running fine now

now so we have successfully done the

setup now it's time to test the

query we need to create the song first

because there is no record in our

database table which is songs there is

an empty here there is no

record so I'm just trying to write the

query to fetch all the

songs I created the query data object

I'm providing the

query and I'm sending the query in the

HTTP

request when you test the API graphql

API you will get the data or the

response in data object and we have the

songs I'm just expecting the songs

array uh uh let me run the application

in development so you will understand it

more

deeply application is running

now let's try to write the query to

fetch all the

songs if you write the query or you can

do without without query I'm going to

write query

query and I would like to fetch all the

songs ID and the

title so you got the result in the data

object and we have the songs

array one more thing if you write the

name of the query you can also do that

if you have experience in graphql then

you will know what I am doing you I'm

just I just gave the name of the query

get songs you can also do that it will

work fine there is no

issue now we're going to test a single

song

query

this time first step I created this

song and I created the query

object now we need the variable this is

how you can Define the variable in

graphql so I'm providing the variable ID

here you can exactly

query in your graphql playground let's

say

it this is a new

tab I can give you the name of the query

get

song let me copy that get

song now I def I created the get song

query and I'm expecting the ID as a

variable here I'm providing the variable

ID this is how you will set the query

variable this is a another way to fetch

the get song query I already taught you

this method it will work fine you got to

provide the

ID and here you can expect the name it

will work fine but this is another

alternative way of doing this

thing if you have an ID you can provide

the ID

here ID

we don't have any record that's why I

got the

error now we going to test

it you can see our test has passed now

because first we are creating the song

then I'm providing the

ID variable from the new song object you

don't need to change anything here you

can also do expectation

for assertion check for the status code

here instead of calling this

one that's why I I'm expecting the 200

status code and it is going to give give

me the response data and the song and

I'm checking on the based on new song

both are

same now our next step is to test the

create song

mutation it is the same way you define

the mutation I give the name create song

mutation instead of ID I'm expecting the

create song input we have created the

variable and I'm getting the create song

input we have title and here you can

provide the values for your

variables if you want you can do the

exact same

thing from your graphql playground let's

say I can say I'm going to create a new

song I just past it pasted the

mutation if you run there is no query

variable for create song

input let's define it you have to

provide the title I can

say

lover

song you can see the lover

song now I can provide the ID here let's

test it

here I provided the ID so I got the song

object there is a data object and we

have a create song

object that's why I used create song

Here create sing do title should be

animals our test has passed now we need

to run update mutation similarly just

like for just like with create

mutation it is expecting to arguments ID

and the update song input and we are

providing the ID in the variables and

update song input here

here it is going to return the affected

with

integer now we're going to copy this

delete

mutation delete is expecting only the ID

and it is going to return the

affected I defined the delete song

mutation and here I'm expecting the

value which is

one

our test have has P tests have

passed

query and we also need to test delete

[Music]

mutation delete mutation test has passed

F this is how you will do end to end

testing in

graphql in this lesson I'm going to

teach you the concept of

caching Apollo server provides caching

on the server site you can implement

it caching is a process of or method of

storing copies of file or data in a

temporary storage location

or cash to be accessed quickly like you

want to store the data temporarily in

some type of in memory built-in memory

you can store the data Maybe for 30

seconds or 60 seconds or a 1

minute it's called caching what is

server side caching you want to store

let's say you want to fetching the query

results you have a

query and user is fetching the

query constantly after every 10 seconds

after every 20 seconds or after every 10

seconds in that case you need caching

you don't want to send the request

backend server to DB server again and

again so it will increase the massive

traffic

load you are thinking why do why need

why do we need

caching if user is fetching the query

after 3 seconds again and again you did

not implement the caching your

application will send the request to the

backend server DB server and it will and

it will fetch the data from that server

again and

again it will decrease the performance

so the help of caching you can improve

the performance of your

application you can avoid unnecessary

request to server because the data will

be fetched from the cache

immediately you can reduce the bandwidth

which will be benefit to user you can

reduce the massive DB

loads with the help of caching you can

handle massive Network traffic

request yeah you can decrease the

service

calls so that was the basic fundamental

concept of caching now we're going to

implement the caching in in nests

project nests already using Apollo

service AP poo server Apollo

package so we're going to install the

package uh install this caching module

Apollo server plug-in response

cache this plug-in helps optimize the

performance of graphql queries by

caching the responses

this this plugin will help us to Cache

the response and serving the data from

the cache instead of executing the same

query

repeatedly our next step will be

register the caching

plugins when you install this plugin you

can register it as a plugins

array I have set the default maximum age

which is 5 Seconds I'm

saying hey

Apollo you can keep the data in

cash for 5

seconds after 5 Seconds you have to

refresh the

cache you have to refresh the

data and then you need to create a

directive cash controls SC private or

public you want to fetch the data

publicly or you want to fetch save the

data privately private represents a cash

control scope where the response should

be cached privately if you want to fetch

the authenticated user something like

that then then you need to set the

private represent a cache control scope

where the response can be cached

publicly this directive will have max

age scope and inherit max age and you

can apply cache control directive on

field

definition you can apply on a fing field

like title field in a song

type you can apply on object interface

and Union the max age is an optional

argument of type in that represents the

maximum age of the cach control in

seconds how long the

response can be considered a fresh and

cachable you can read this documentation

of maxh I've written down for

you private and public scope this will

be used for parent let's suppose your

query is dependent on parent

query then you need to use this

one you can also set the cach control

set cach

hint in the resolver by using this

line our next step will be apply the

cache control directive I applying it

for titled field inside the song

type cache control maximum age for 30

seconds I'm saying to Apollo hey

Apollo you can keep the title field

record

for 30 seconds in a

cache if user is fetching this title

field constantly after 20 seconds or

after 10

seconds then it will fetch from the

cash if user needs to fetch record after

a minute or after a 2 minute it will

fetch the data from the DB server but it

depends on you on your case on your use

case but 30 60 and 40 are the

recommended values on the based on

Apollo

documentation Apollo server uses

inmemory cache by default we are we are

going to use inmemory cache but you can

also configure different backend like

redis or M

cach you can also apply cash control

directive on a complete type let's say

if you have a scenario where you need to

fetch all of the fields from a specific

type then you can

add here cache control directive maximum

age to 40

seconds I just give you the basics

Basics when you implement in real world

scenario in real world large application

you will know your use case better now

it's time to implement it or you can

implement it by your own

let's install the plug-in

first plug-in have installed let's

import it in the app

module now we're going to register the

plug-in into plug array when you are

creating graphql module you can register

it

here so our third step is to creating a

cache control

directive I can do it

here it will have max age scope inherit

inherit max age private if you want to

dig into more deeper you can look at

from the Apollo server

documentation when you Google Apollo

server

caching this is the document you got to

read if you want to dig into deeper what

is Max age what is cach control scope

you can read this

document this is the implementation of

caching in AP poo server

if you want to do ready setup you can

also do

that we have created the cache control

directive

now I want to apply the cache control

directive on our field right now I have

only one single Field title I'm saying

I'm assuming that my

title field is going to be

feted

after 10 seconds I have a query in that

use case like client is asking title

field again and

again let's try to test it

first

my application server has

started now I can say I want to access

the

query of the songs I want to fetch the

title you can see it's working fine

now let's fetch the title again

now it is accessing the title field from

the inmemory

cache one last thing you can also apply

cache control directive on a type here I

want to say I have only single type

that's why I want to use it for only

demo purpose in real world application

you will have a different use case

restart the

[Music]

application

[Music]

my application is running now I'm going

to access this song FEI

songs it's still working

fine if I try to access the

song we need to provide the ID

let's fetch the

ID I'm going to copy the ID and let me

paste it

here now I would like to access the ID

and the title let's access the title

only or the

ID now the data is is going to be

cached I can access it

easily it's working

fine in this lesson I'm going to teach

you the concept of data loader why do we

need data

loer we have this schema I've already

found example project regarding data

loader we have a user and we have a post

there is a

relationship between user and the

post when you send the graphql request

to fetch all the post and you also want

to the owner of this post who has

created this

post under the

hood graphql your application will send

a a different different a new data

request to the database a new request to

the database to fetch a user for each

post this will decrease the performance

of your application because you're going

to do lot of database

request here your output will look like

that if I will show you

here let me show you with the help of

example I'm going to send the

request it is going to take a 3 seconds

because I have set this delay for the 3

second we have how many post we have we

have three post you can look at the

schema or our database I don't I'm not

using any database

here

so here is the

data we have a three

post inside the post we have a user

ID when you look at the user service we

have all of these

users every time let's say I log the

message fetching data from DB

let's example you can say that getting

user ID 1 fetching the user ID one this

is the you can imagine this is the

database

request every time it is going to fetch

the post for each user against post it

has to fetch the record from the

database you can imagine if you want to

load 50 post and you have to send the

API or backend DB request for each user

separately so what data loader will do

data loader will batch all of the users

it's going to wait and say I can send

you

request here what data loader will

do it will say

I

will get all of the IDS of the

users like one 2

3 and then I will

fetch all of the

users for all post and then if you need

any post if you need any

user against each

post you will fetch from the cash or

from the data loader cash data loader

maintains cash

also did you get the

point let's say I'm going to add I have

four users inside the post

service I'm going to add post

for title post

for

something and user ID which is for this

one application is running now I'm going

to send the request to fetch all the

post

now I got the for post and it has sent

the DB request to fetch a single user

what we can do we can say I want to

fetch if we are using data loader please

fetch all the users it's batching all

the users from the DB and maintains a

cache and next time our application will

fetch the user from this cache

I have already implemented the data

loader in this project actually I found

the source code on the internet to

explain the data loader it's a simple

source code so I thought I should teach

it with the help of this source

code inside the post

resolver here they are resolving the

created by field created by and it is

going to return the

user here instead of loading the user

from the database let's user service

will send the DB request so I'm going to

comment and now you will see the magic

instead of loading the user from the

DB I would like to fetch the user from

data

loader now we're going to send the

request

you can see that getting the users with

ID 1 2 and

4 it has bashed all the users and

created the user map to send the ID's

record to data loader and here is the

result so let me

explain what this source code is doing

if you check the app

module here we are providing the loader

I created the create user loader and

they are injecting the user

service inside the user service inside

the create user loader I'm passing the

user

service to work with data loader you

only need a single package which is data

loader this one you have to install only

the data

loader here you will have a user

loader what this loader will do it is

it's nothing more it's just a function

takes a user

service so I created the instance of a

data loader the ID will ID would be

number and another type which is the

object should be the

user this when you create the data

loader you have to provide it is going

to give me the IDS all of the

IDS and here I can fetch all of the

users against IDs here I did the users

map you you saw the users map here 1 2 3

because data loader Works in this way

you have to provide the results in this

way like I got 1 2 4 then I did the map

to fetch all the records ID 1 2 and

4 we created the user loader I have

attached inside the context

object remember graph resolver can have

four arguments in for context and

parent we have user loader here to fetch

all the users against a

post here this one inside the post

resolver I'm resolving the created by

field I got the user loader from the

context here you need to load the

user from the user

loader I got the parent I parent record

from the post which is the

post so I got the user

ID which we saved

here we have one more thing we have used

a schema based approach to build graphql

apis but I also wanted to show you

another way to build graphql API which

is code first approach this code first

approach will generate the schema.

graphql file automatically it depends on

you but I like the most schema based

approach but you can use both of them it

depends on your use case this is how you

will Define the graph qu object

type but we have worked with this schema

based

approach let's say you want to create

this graphel type which is posted with

the help of code based

approach you will say this is the graph

object type you can get it from nestjs

graphql package and this is the field

you can say this one this is the field

and you can

say title field and we have the body

field and we have the user ID I'm not

I'm not saving into the graphql datab

graphql graphql type that's why I keep

the user ID for entity based to build a

relationship with them so created by

this is the relationship between a user

here you can see that created by the

return type should not be null that's

why I they have used the user this is

this represents the return type what

your field will return so it's the type

of this created by it should return a

user user

type similarly you can look at the user

entity

object type this is how you will Define

here this is graphql type and my user id

the type should be number that should be

int that's why it's a nonn knowable

field and it should return or the type

of this ID should be int and we have a

field which is graphical type so this

code will be converted into this schema

type and how can you resolve the

resolver when you look at the post

resolver this is the resolver and I say

this is the post resolver that's why I

provided the post

entity now we have the post resolver the

query

tag so here you want to say what

resolver this will do in we are in the

post we are here

so this query will return all the post

and the name of the query should be post

I'm resolving this query so I'm fetching

the post similarly if you want to

resolve the created by here this one you

have to provide the resolve

field is all

field there is a field inside the post

Ty which is created by and it should

return a

user so this is the return type this is

how you will mention the return type it

should give the user and I got the

parent and the

context this is a uh nextjs has

documentation on

graphql you can learn more about a code

based approach if you like the code

based approach you can learn more about

from the

[Music]

documentation this is the code first

approach the object types you can read

the documentation if you are not getting

what I'm talking about you can just read

this text it will help you to understand

the code very easily so this is how a

field and type should be post array I

want you to check this documentation one

more package I want to share you have

graph nestjs graphql

tools if you want to use the code based

approach

and let's say you are using post or type

orm this is the package if you want to

work with

database and and you want to use loader

they have already built a data loader

here if you like this package you can

implement it it's simple you need to

provide resolver user object type user

resolver here it will have graphql

loader you only need to just provide The

Decorator graphql loader and it is going

to implement the loading stuff

here if you like it you can implement it

there is a this is how you will

Implement one to many many to one and

this is the usage

I just want to show

you you can do if you want to use

database and data loader you can

Implement by using this package this

package also have more features on

pagination sorting and field extraction

Etc if you want to fetch data from

external rest API you can do that we're

using Apollo server AP poo server

provides a package to fetch data from

external rest API a

poloo data source rest I have attached a

started

project I have already in I have already

have this package in package.json file

you have to install it Apollo data

source

rest you have to do npm install to

install all the dependencies

this is a class you have to extend

it we're going to do we're going to

fetch

todos from this Json placeholder API

it's a fake API with real data let's say

I want to send to-dos

request it is going to give me all of

the to-dos I want to fetch this rest

API

now this is how you will implement

it you will have this schema you will

create the schema to do ID user ID title

completed with

Boolean I'm using the same property I

defined a graphql type and then we have

a query query to fetch all the

to-dos I have a to-do module inside

to-do service to-do resolver now to-do

service is is going to f fetch the data

from external rest API instead of data

database inside the to- do service here

you have to extend the rest data source

it will it will ask the call the super

Constructor this is the base URL I'm

going to call this.get to fetch all the

to-dos you can use this method I I can

get the data source object from the

context here you got call data sources.

too api. getet too I'm talking about

this too API like this one so another

important thing this is how you will add

a data sources inside the context it's

an asynchronous so I provided the data

sources if you want to implement you can

go ahead and do it and let me do that

for

you I have I have to do docraft in my

started kit

project now let's extend data

source rest rest data

source let's have the

Constructor I'm going to call the super

Constructor now let's set the base

URL I can get the base URL from

here I don't need to provide todos this

should be the base URL now let's define

a function to get

to-dos and it is going to return the

array of

to-dos I can get the type from the

source. graphql file the typescript file

I've generated the typing by executing

this

command npm run generat typing

so let's call this

dot here disor get and provide the path

to

do is everything right I can check the

path which is to

do so we created the data

source and now we have to add this data

source

into to do resolver we got to call this

actually we need to add in the

context I'm going to create the data

sources

function it's going to return a to-do

API let's create import to-do

service it's going to return the object

and the function is going to return the

object now I can add in the

context

here it looks good so you can use the

context object here inside the to-do

resolver to do resolver let me get the

context data sources and I'm going to

call all this

method data source is a function there

is a to-do API object and we have get

too

function let's start the

project project is already Runing on

3,000 let me stop the project let's run

it again

my project is running I'm going to send

the

request I got all the 200 toos

Unfortunately they don't have pagination

otherwise I can implement the pagination

but you got the concept how to implement

the rest data source if you want to do

more Advanced Thing by using the rest

data source package there is also a

caching functionality you can override

the method I want you to check the

documentation if you want to implement

the rest data source there is also a

data loader you can also use the data

loader with rest data

source I want you to check this

documentation it also provide to fetch

duplicate

records you can read the documentation

to understand how to use the

cache stuff like

that in this module we're going to use

Prisma orm and we're going to build rest

apis Prisma is an orm in nodejs or

JavaScript when you look at the

documentation it's they are saying it's

a Next Generation orm for nodejs and

typescript

project it's similar to type orm but it

is faster it's an efficient they are

maintaining this project

regularly so you can look at the use

cases and customer stories when when do

you need

Prisma you can read the customer stories

and use

cases so in this video I'm going to

teach you how to set a Prisma in next

nestjs project you can also get the

Prisma documentation from nestjs package

from nestjs package inside the njs

documentation you will find a Prisma

folder you will see the Prisma section

here is a Prisma orm

documentation the first step we need to

install the

Prisma I have provided the started kit

code for you you can go to the starter

branch and run nbm install to install

all the dependencies this is just a

basic Nest CH

project I don't have anything here just

Basics basic setting for nest CH

project it is taking some time to

install the dependencies meanwhile I'm

going to create a new database for

Prisma because we're going to use postp

with

Prisma I'm going to create a new

database

Prisma API something like that you can

choose any

name all the packages have

installed now we need to install a

Prisma as a dep

dependency

Prisma left dependency has

installed now we need to initialize the

Prisma project I can use npx init Prisma

in

it it will set up the Prisma in our

project you will see schema. Prisma file

inside the Prisma folder here I'm

telling I'm going to use Prisma client

Library this is my post database

provider this is my database

URL they have also added a created EnV

file here we have postp database URL

make sure you have ADD theb in the git

ignore I think I've already added it yes

no I cannot see that let's add EnV I

don't want to put push my EnV to

GitHub they have already installed post

so I'm going to work with

post this is how you will set a Prisma

in your project in your nestjs

project in the previous video we have

set up our Prisma

application now we're going to create

our first

model I'm going to create the song

model the type should be int

and by

default this should be

int by default I'm going to set it to

Auto

increment and this is the

ID let's add another property this time

the type should be

[Music]

string but we did not set

database URL for the

post I'm going to create a new

database let's create a new

DB

Nest Prisma app or Nest

prisma-p my username or owner is

postgress now we need to replace the

owner here

postgress and your

password and the name of your database

and schema should be

public I'm going to run the

application my application is running

fine let's try to check the tables

inside the schema I'm going to

refresh and inside the tables I cannot

see any table because we did not migrate

the

database let's create our first

migration migrate

F Prisma migr F and the name of your

migration I can say in it this is my

first

migration

I think I did not provide the right

command Prisma

migr

DB or Dev yeah npx PR migrate

Dev Das Das name of your

migration this is my first migration

that's why I chose the init name but you

can choose anything

here

Local Host provided DB credentials are

not

valid post

SC there was an issue with double

s now a new migrations folder has

created inside the

folder we have in it migration

file we have song table this is the

migration log

let's try to check in our database I'm

going to refresh my

tables and you can see the song table in

our

database but we also have two columns ID

and

title in the previous video we have

created our first model and we ran

migrations but Prisma also provides a

Prisma client to perform cred operation

this Prisma client will generate the

correct

apis correct functions for song model

you will have prism client. creat song

prism client. find song all of these

methods in the prisman client Library

here we are using the prisman client but

we have to install this package Prisma

client and P install at Prisma

client this package will provide scrud

operations for all of your

models this Prisma client will interact

directly to the

database so we created the Prisma Cent

installed the Prisma client now we need

a service inside the source directory

and I call it Prisma dos service.

s it's injectable

service

exort class Prisma

service and I'm going to extend the

Prisma

client Prisma client

here we also need to

implement on module in it because we

have to set up the Prisma client when

our application is

running I can call it on module in

it on module in it this

do

connect this connect method will connect

our uh connect this Prisma client to our

database

I have I have not imported injectable

decorator let me get it that's all you

need to connect Prisma client to

our

database so we will not use Prisma

client we will use Prisma service to

interact with

database we're going to talk about how

to create cred

operations we have created a song model

here I want to create the correct end

points one more thing I did not talk

about or I did not teach there is a

resource

generator this CLI command will generate

the correct API endpoints controller

module service dto object something like

that if you need to scaold your

application you can use this command

resource

it can also works with work with graphql

code first approach schema first

approach or you can create a micro

service or you can create the web socket

but I chose the rest API because I would

like to build the rest API yes I also

want to generate correct entry end

points we have the songs model we have d

object entities so on

controller

service we have all of these method

inside the

service we have created a Prisma service

now I'm going to use a Prisma service

here to interact with database can call

it

Prisma Prisma

service it is going to give me the

error that's why I use this

path first of all let's create the

create

method return this do

Prisma

Dot Song you can see we have a song

object there is a create method and you

have to provide the data here you have

to provide create song

dto one more thing I want to talk about

you can use the types from Prisma client

Prisma client already generated couple

of typescript typing let's

say first I need to import

Prisma from Prisma

client

you will find book create input the

type in this type you will have title

field we also need to update inside the

song

controller we got to get Prisma client

and you will have book

DOT

book create

input my vs code is not giving me the

hint or

suggestion now we're going to run the

application it is going to give me a

couple of Errors

maybe oh it's not a book it should be a

song because I'm accessing the song

model I'm using the

book

song song.

input not a book song create

input

I did not import Prisma service inside

the song

module because we have to import it

that's why you have to register it as a

provider

Prisma service so I can get the Prisma

service my application is running fine

now now we're going to test it with the

help of fresh client let's create a new

file I can say HTTP

client.

HTTP create

song post

HTTP HTTP Local Host colum

3000 SL

songs what is the name of the API I can

check it from the

controller we have the

songs content

type application

Json let's provide the

title follow

me you can see a new song has created

successfully now we're going to write

the function to fetch all the song This

start

Prisma

I'm going to reload my window it is not

giving me

suggestions Prisma

Dot

Song dot find many there is a method

find

many

let's try to get all the

songs you can see I have a single

song now we have to implement the find

by ID this do

Prisma do song now it is giving me

suggestion find

unique and we have to provide the

ID where clause and you have to provide

the

ID

let's try to fetch the song on the based

on

ID fetch song by

ID so I got the song by ID if I provide

the invalid

ID I should get the empty

record I'm getting issues here I think I

need to generate the typing you can call

this method npx Prisma

generate it is going to generate the

typing inside the node node modules and

Prisma inside the Prisma you will get

the typing I got this from

documentation this typing will be stored

inside the node modules inside the

Prisma and the client

directory generated Prisma client

reload the

window now the error should be gone

now I have to update it it's a song

create

input we also need to update in the

controller we have the song

controller

here it should be

Prisma Prisma

SL song create

input I have to get this ke Prisma

client now the error should be gone now

it looks

good

so I can create a new

song and I can fetch all the songs that

looks

good in this lesson I'm going to teach

you how to create update endpoint

actually we have already created the

update

endpoint you will see the patch endpoint

Point inside the song

controller there is also a method inside

the song service there's an update

method all I need to do is to use a

Prisma service inside the song

service we have have to use the update

method from the

Prisma and there is an update method

inside the

song

update here you got to

provide we clause and the

data where and

data we have to fix a little bit

changing

here I'm getting I'm going to get we

clause and I can get the type for for Vi

song We unique input similarly I would

like to change the type here Prisma do

song update

input you can remove the V because both

the key and the value are same so I can

use a single

V we also need to update the type in

controller file let me update the type

here

here I would like to send the object

instead of single parameter which is

ID here I can change the type Prisma do

song update

input we also need to update the find

one a little

bit

I would like to get the songw

unique input and let me get the

songw

unique

input and I'm going to

provide song wear unique

input

we also need to

update controller for the find

one let me send the ID in the

object because I'm receiving the object

here

here if you want to look at all of these

types where these types have

stored when you go to the node modules

you will find there is a package

Prisma do Prisma

client you will have all of your types

in index. D.S

file so I can get song whereare input

you can see we have a song We

input can say

type here here we have a song We input

you can have ID and the

title here we have the song where unique

input you have you can have ID and or

note in the

title now we have to test it run run the

application cannot find

primsa let me fix

that there is an issue

Prisma

now my code looks

good I'm going to send the update

request from my rest client from my HTTP

client the song by ID we have to send

the patch request instead of

put and going to update this song with

id2 copy the content

type dancing

feet let's see a song has updated

successfully if I fetch the song on the

based on ID it looks good we have

dancing feed

let's create another

song I have created another song I would

like to update the

title my title has updated so you can

fetch all of the

songs it looks

good we have implemented the update

operation now now we have to implement

delete

operation I'm going to use the same

strategy to delete let me get the ver

clause in the

input there is a method in the

Prisma Prisma do song. delete it is

going to accept the V

Clause now I have to get it in the

controller we need to pass

that inside the song

controller here I have to provide the ID

inside the

object

ID

let's try to test it with the help of

HTTP

client I can say delete song by

ID I'm going to provide the ID instead

of patch we need to use the delete

operation you can see this song has

deleted I can verify by fetching all of

the

songs you can see we have only only two

songs right

now now we're going to build

relationship between

models Prisma also provides one to one

relation one to many relation and many

to one

relation and also have many to many

relation I'm going to add a new model

artist let's add Fields inside the

artist I will have the ID and the name

of the

artist now each

song an

artist

I'm going to add one to M relationship

between artist and

songs each artist can publish many

songs I saved the application you can

see it has automatically added a

relation let's rename a small a to a

capital A to small a

here you can see there is a reference

here

artist and fields which is artist ID and

the reference with the

ID now we have to run the migrations npm

run

migrations oh I have to run

npx Prisma migrate

Dev the name of the

migration which is ADD

artist it has also generated the Prisma

client queries or Prisma client

types when you see the migrations you

will

have the create table cury it is going

to create the artist table it has also

added a relationship between song

relationship between songs

model let me try to check the types you

can check it from Prisma client index. D

dots do I have the artist type yes let

me find artist create input yep it has

generated the types for

me now I'm going to generate a new

resource for

artist an artist resource has created I

don't need entities I'm going to delete

them

here I also don't need entities in this

song because we are defining our models

in the schema. Prisma

file let's create the

artist we have to open the r service and

here we need to

inject the artist the Prisma

service I can get it from the song

service which we have to import these

two dependency Prisma service and the

Prisma

client I'm going to copy the

Constructor here we have to

find the Prisma create

input command F to to

find artist

create

input yes I would like to use that type

I can get it from the Prisma

client

Artist Artist create input that's it now

I can

use Prisma do

artist do

create here we have to provide the data

object and inside the data I can

provide create

artist

dto one more thing you need to add

Prisma service in the artist

module we have to register it Prisma

service let me import Prisma

service and here I need to add Prisma

service we also need to adjust a type in

the controller for artist controller we

have to update our

type I have to use the same

type Prisma dot artist create we have to

import a

Prisma otherwise it will give you the

error I'm not going to use the create

artist

dto so the artist create input can take

the name of the artist if you want to

inject the multiple songs you can also

do that you can look up the

documentation of Prisma how can you

insert multiple

records if you want to do in this way

you can also do that artist unchecked

create input but I'm going to use this

one simple one npm R start

Dev my application is running fine now

let me open the HTT HTTP client let's

send the

request to create new

artist create

Artist

Artist here I can provide the name of

the

artist can say Martin

Garrick a new record has created

successfully the artist record has saved

let's add a new

artist V

another artist has

created we have made one too many

relationship between artist and songs

when you add a new song you can add a

relationship for the artist here when

you check the schema. Prisma file you

will have the artist ID in the song

model that's why we need this is how you

can build a relationship between song

and the artist so what I can do inside

the song

service we have to

expect the song actually author ID I can

find

that song

create

input so I have this song create input

type I also have song unchecked create

input did you notice the difference

between these two types here we have the

artist ID I can add the artist ID if you

want to insert a complete artist while

creating a new song you can also do that

you can look up the

documentation and here you

can you can do in this way

you can provide the array if you want to

do that if you want to insert a single

record you can also do that but I just

want to show you the way to

add

record so I'm going to use this

type instead of

simple song create

input now you also need to provide the

author ID in the in the request

parameter here I'm creating a new song

here let's provide the author

ID which is one I'm going to create a

new song let's say

Animals by Martin

gck I got an issue not an author ID it's

an artist

ID why I'm saying the author ID I got

the record with this author ID if you

want to

query the artist in

the response let's say I'm going to I'm

going to fetch all these songs but here

we have artist ID null here we have the

artist ID one if you want to populate

the record of the artist you you can do

that in the find menu and here you can

say

include artist to true that's

it let's fetch all the

songs here the artist ID is null artist

is null here you can see

the artist ID one and we have a complete

artist

record that's how you do

population we have used this include

syntax you can also use the connect

object if you want to make the

connection or update the reference ID

you can use the

connect now we're going to implement one

to one relationship between two models

we're going to have a user model here we

have a one to one relationship between

user and profile each user will have one

unique profile in the profile we have

photo we have the phone number of the

client of the user this is how you will

make a one toone relationship user and a

relation and this makes each profile

will have a unique ID of a user table

then we will generate Prisma

migrations then we will generate a new

user with the help of nest generat

resource a user we're going to use cred

AP endpoints and finally we're going to

save a user on the based on profile like

when we are when we are saving a user I

also want to save the profile this is

how you can do that profile and a create

object and the attributes of profile

table it will automatically made a

relationship between user and a profile

and finally I want to fetch all the user

with the

profile if you want to implement it you

can do it but let me show you how can I

implement it I'm going to copy the

model here here here inside the

schema let's add two new

models I've added two new models let's

run the

migration

npx Prisma migrate Dev the name of the

migration one

to1

[Music]

relation it has run the

migrations and now it has also generated

the types inside the Prisma client I can

double check that from the Prisma here

you have all of your user types user and

profile when you search the

profile here we have profile

stuff our next step is to generate a

resource Nest generate

resource

users

select rest API end

points getri

of the

entities and I need to inject Prisma

service inside the

module inside the users module I have to

inject the Prisma service

here Prisma

service inside the user service we need

to inject Prisma service

dependency I can get that from the song

service we need the Prisma

service

and I'm going to copy this one as a

Constructor so we have to call the

create method I'm going to copy the

exact create

method and provide it

here that's it this time I'm going to

use the create user

dto I have not defined the properties in

the create user user dto if you want to

add the validation you can use the class

validator I taught you earlier in the

previous

modules we will have photo the URL of

the photo should be

string and phone number the type should

be

string now we're going to I'm going to

copy find all method

and I'm going to use this profile I want

to fetch the profile with each user now

let's try to test it run the

application this create object is used

to create an nested object a relation

relation

object

let's create a new

user

users provide the name of the user

jendo and we have to provide the photo

URL some

api. com/

phos 1. J

APG and you need to provide the phone

number let me create a new

user a user has created successfully

let's try to find all the

users VCH

users

here you can see that I can see the

user and we have the profile object

inside the user you will also see a

relationship with user ID one which is

one that's how you implement one to one

relation in this lesson you're going to

learn how to implement many to many

relationship between

models I have this use case one blog

post can belong to many categories and

many categories can belong to a single

block post so there is a many to many

relationship when you implement many to

many relationship you need a third model

in the third model you store the foreign

key of your first model and the foreign

key or prime for foreign key as the

primary key the foreign constraint here

it's a it's a foreign key of category

table and in Prisma you define the

primary key by combination of post ID

and the category

ID this is how you will make uh many to

many relationship now the categories

instead of categories array you will use

the categories on post array the same

stuff here instead of using post array

here you will use the categories on post

array and then

you we will generate

migrations we will generate migrations

and it will also generate the Prisma

client

types and then we will generate the

resource post we will create the post by

using this input type post create

input and I also have to update the type

in the

controller and this is how you will send

the request to create a new

post here the title of the post one to

many

relation this this is the Prisma post

and it it can have two

categories here you can say I I'm going

to create a new category this post can

also belong to Prisma category this post

can also belong to nestjs category that

is why I created two categories you can

see that category number one and this is

category number two here I here we have

the array of the

categories similarly you can do the same

thing if you don't want to create a new

post you can connect with existing

post I'm going to teach you transaction

let's say I'm going to write blog post

on transactions in

Prisma and here this post also belong to

nestjs category and Prisma category

that's

why I'm I'm connecting to category

number one and the category number two

and finally you can also do a relation

queries with the help of this type post

where uni input also have to update in

the

controller this is how you can send the

request categories this is a we Clause

category and the name you can check all

of different type of queries in the

documentation let's try to implement it

first if you want you can Implement by

yourself many to

many

relation I'm going to create a post

model and my next model model is

category it will have name and the ID

and my third model is categories on post

I'm going to save now you can see

that these two properties are inside the

categories on post I would like to store

the

date and I want to store who has created

this

let's run the

migration it has also generated a Prisma

client

types you can check it in the node

modules at Prisma /

client our next step step is to generate

the post resource we're going to perform

some cred

operations please select the rest

API yes I want create entry end

points I have the post get rid of the

entities

one more thing I would like to register

a Prisma

service inside the post module otherwise

you will get the

error now we're going to write the code

in to create a new

post we also need to inject Prisma

Service as a

dependency I'm going to copy these two

lines and I'm going to paste here Post

Service let me copy The Constructor we

need to inject the

dependency I'm going to copy my

create

function

something is

missing I have done something

wrong so let's you use the

Constructor pris

private Prisma and Prisma

service let's use this type

actually I don't need

that let me copy the fold

create what is

this now it looks

good so we also need to use that post

create post create input in the post

controller let me import

Prisma now it's time to test this

application

the application is running fine let's

send the API

request I'm going to copy my API

request here I'm going to create a new

post and I'm going to also create a two

categories so you can use the create

array

inside the create array I have the

category this is the post on category

object so that's why I use that

properties let's send the

request it should be 3,000

or 3,000 it should

3,000 now you can see that one to many

relation post has created

successfully now it's time to do a

register another

post this time I don't want to create a

new

category create a post

with existing

categories I would like to create a new

post and I want to use

the category number one and category

number two let's create a new post has

created it has also made a

connection with this category you can

double check from the PG

admin meanwhile I'm going to write the

code to do relational

queries let's

update the find find

all that looks good we also have to

update the

get inside the post

controller

now we have to fetch all the post with

nestjs

category so you can do that you can

learn more about how to do queries in

Prisma

documentation I'm going to send the

request the post the should be

3,000 now you can

see I got these two post with the help

with the I justed query with

category what is my name of the database

let me get it from

EnV PR

Nest Prisma

DB here I have Nest Prisma DB let me

find the

tables and we have post category and

categories on post let's look at the

post we should have two

post you can

see I have one too many and

transaction I must have two

categories you can see that let me find

categories on

post here you can see I have four

records there is another way to use

transac ction feature if you have to

perform the batch or bulk operations

like delete manyu create manyu and

update manyu you can use all of these in

a one query you want to create three

records you want to delete two records

or maybe you want to update a single

record or maybe you want to update five

records so in that case let's say if any

query fail

then all of the operation will be

discarded I'm going to run multiple

queries at same time if any query failed

you will not get result

back you can use this query or

transaction API when you want to create

batch

operation here is an example

I want to find all of the post I want to

find all of the artist I want to find

all songs I want to find all

applications in a single query if this

query fails it is going to give me the

this operation this complete operation

will be discarded I will not get any

result that is why you use this

transaction

API to implement the demo or to

implement the transaction

API let's do it in app

controller we have to inject Prisma

service I just want to show you the demo

how can you use the transaction

API this my

service we have to inject it

here I can say

transaction let me register Prisma

service now I have injected it

here we have to import

it sounds good I'm going to create a new

method with name

sequential and get

sequential result results this could be

the name of the

query and here I'm going to copy my

code so let's try to test it I'm going

to run the

application let me send the request for

sequential query in my HTTP

client

sequential

query

HTTP Local Host colum

3000 and

sequential you can see I got the result

of all of my post

applications this these should be post

the

songs

and here you will have application these

are all the applications with customer

ID this is how it will

work if you want to add include or to

fetch nested record you can also do

that now I'm going to talk about the

concept of nested

queries this topic already is in the

transaction

API I'm talking about transaction when

you have this type of use case let's

say first I have to create the customer

email customer or the user and then

there is an address let me look at the

model structure we have a customer model

and we have an address model there is a

one toone relationship between customer

and the address and I have created the

enum application type and I have the

application model and the type should be

application type and default to now and

I choose a loan loan

here and I have made one to many

relationship between application and the

customer we have the applications array

here so let's say I want to create a new

customer address and here I'm creating a

new address and here is the Fe here are

the fields of

customers and I'm going to create

applications basically we going to we

are talking about a banking type

application let's say a customer comes

to apply for the loan customer can apply

for multiple loan applications loan car

financing or business financing a

customer can apply apply all of these or

can can apply to one or second type

application so tenure of your

application would be 5 years or 2 years

how many amount you want how much how

much loan you

want so this type of application when

banking banking in banking application

when an application comes they create a

new customer record they create the

address and they create the application

based on current user or current

customer

demand let's say a new customer comes

with business financing application John

wants to get the business financing from

a bank so he's decided he's going to

apply for business financing application

what under the hood is saying what under

the hood banking application will create

a new customer they will create a new

address and they will also create a new

application but they have a

feature a customer can apply for two

loans two applications or three

applications he can also apply on

business financing he can also apply on

car

financing so that's why there is a

create array

here what what are the benefits of using

transaction under the

hood Prisma is using transaction when

you run the nested queries these are all

the this is the nested

query we are creating address and we are

creating applications this is the nested

query let's say if an error comes here

if I will add the invalid value

here it will not create the complete app

application it will not create the

customer it will not create the

address so that is the benefit of

transaction I'll show you with the help

of demo this is how you can

implement the nested queries in Prisma

I've already done that for you I'm not

going to implement it here first of I

can walk walk through the code I created

the customer model we have the ID we

have the name field we have the email we

have the address and we have the

applications

array so address should be here it

should be at the top here so I have made

a on to one relationship between address

and the customer here is a unique

denotes to denotes to one to one

relationship we have Zip City Country

inside the address and there is a on

toone relationship between customer and

the address but I also have one too many

relationship between application and

customer so I told you a John can apply

for car car financing he can apply for

business

financing that's why I use the

application

array so the tenure amount application

type I have set the default to

loan so that was our model structure

next step I have executed nested query

Migration by executing this command

nested

queries

here it is going to create the customer

table it is going to create the address

table and create the constraint with

customer and the address it is also

going to create uh application table and

create constraint between application

and the customer

and then I have set the default value to

laan and then I have created the

application resource by running Nest

generate resource and you will see the

application inside the application

module I have injected the Prisma

service and then here I'm injecting the

Prisma Service as a dependency and I

just

called create application dto by using

the customer customer create input you

can double check it from the customer

create input you can get name email

address and

application all of this stuff

here name

email address I provided the address and

I'm creating it here I also can provide

the applications array you can check the

type by copying it and type and paste

so it should give me

the this one

type so I got this application create

nested with custom customer input so I

use the create did you see I use the

create can have the array so create can

have the array

here so you can provide the application

object

here if any fails the transaction will

roll back or discarded the

operation let's try to test

it you have to send the AP request

inside the HTTP

client here I'm going to send the API

request John J

2 jendo City New York ZIP code this one

amount he wants say

10,000 inue over 5 years and he wants

business financing I'm going to create a

new

application you you can see a new

application has created if I provide the

invalid value I have set the integer

here I'm providing the float or float

value I got the issue now it will not

create an application you can double

check it from PG

admin that's the benefit of

transaction in this lesson you're going

to learn the interactive

transactions what do I mean by

interactive

transaction when one query is dependent

on another query one query result is

dependent on another query result let's

take a use case you're going to build

account transfer feature in banking

application we're going to build this

use case a John has an account in a bank

and he want to he want to transfer the

$100 to Sam account so what would be the

process you have you have to implement

as a developer you have to update the J

account or deduct the $10000 from a Jone

account and then you have to check the

balance of JN account if balance is less

than zero you have to roll back the

transaction the operation should not be

continue

so this query result is dependent on

this query result you can see if any of

the step fails operation will be

discarded if there is an error occurs

here it will roll back the

transaction so first of all we need

account model we will have these

properties

ID balance and the title then we're

going to generate migration and resource

for

accounts we will inject Prisma service

here I will use Prisma account create

input

and I'm also going to update in the

controller we we're going to create

first account John then we will create

second account which is

Sam and we will implement the logic to

transfer amount to One account to

another

account I'm going to create a route

Handler for

transfer we will need transfer account

dto because I cannot use from from

Prisma

types there is no specific type for

transfer account I have to use the

custom data transfer object here when I

will transfer I will send the transfer

account request you need to provide

sender ID receiver ID and the amount you

want a

transfer so we will create a simple

basic transfer from transer method

inside the account service here is the

logic from the controller I will get the

sender and I have renamed to

from here I will have receiver I have

renamed to two and I will get the amount

and first we will

deduct the balance from the John account

by getting by getting the account on the

Bas ID here decrement the amount from

the John account then we try to verify

the balance of the John if balance is

less than zero we have to send the error

back and we have to roll back the

transaction here we here we got to roll

back the transaction but this

transaction object will do for us and

this transaction function it will take

all it will take it's a it's a call it's

a asynchronous operation it it's going

to take TX

so first this is the asynchronous

operation if error comes please scroll

back the transaction do not deduct any

amount from the John account and here is

our second

operation if everything is fine we got

to add balance to the same account and

finally we have to return the balance or

return the

recipient that's our trans transer

process this is how you can test you

have to provide the sender ID receiver

ID and amount you want to transfer here

I'm saying I want to transfer $50 from

join account to Sam account and here I

want to transfer $40 from J account to

Sam account we created both account with

$100 now if I try to send $20 now John

will have $10 in account in his account

if I try to send or deduct the $20 from

Jo

account you will receive this error

balance is less than zero and our

transaction will automatically roll back

this operation that's how the

transaction is helpful when your one

query result is dependent on another if

you want to implement it you can do it

on your own but let me do that for

you first of all we got to create a new

model inside the schema file

I have already done that

model oh I have to implement

here interactive transaction op schema.

Prisma and we have to

add a new

model finally we got to run the

migration

migrate not a

migrate also have to update here M

crate our next step is to generate the

accounts

select the rest

API let me

delete

entities and we have to register a

Prisma service inside the account module

I can register as a provider Prisma

service and we have to import Prisma

service Prisma service

from Prisma

service let's inject Prisma service

inside the account

service I'm going to do dependent see

injection I have to copy this

line and I'm going to paste it here I

also need to get Prisma client so I

imported the Prisma

client let's rename or add a logic to

create a new

account we got to do the same stuff

inside the account

controller import

[Music]

Prisma let's run the application and

create two accounts in our database for

testing

e

application is running now I'm going to

create a new account let me send the

request for account

creation board should be 3,000 not

3001

so I have created the account John now

we have to create another account with

Sam name account has

created let's implement the

transfer account logic transfer amount

not an account transfer amount

logic open the account controller we

have to register a new route for

transfer

amount I'm going to create a post method

we don't have transfer dto let's create

that transfer dto in our dto

accounts

dto

transfer

account -

D.S so here we have transfer account dto

we also don't have a method

yet inside the service account service

so I can

open account

controller let me import transfer dto we

don't have method I can use the vs code

please declare the

method inside the account

service now you will have a method

inside the account

service this is the transfer

method so here we're going to implement

our logic to transfer the account from

John to Sam I'm going to copy the

complete op complete function I'm going

to paste it

here so everything is good to go now we

have to test the

process let's send the transfer amount

request it should be

3,000

let's deduct the $50 from John account

to Sam account I'm going to deduct $50

from John now you can see the balance of

the

Sam if I deduct the $40

again let's use it

here so now the Sam has 190 and the John

has

$10 if I try to

uh deduct $20 from John right now the

balance of John is 10 it should give me

the

error you can see I got the error one

does not have one the ID sender sender

ID with one does not have enough to send

$20 so I got the

eror so I got the error here my

transaction function automatically roll

back back this

operation that's why transaction is very

helpful if you are doing 1020 operations

or 1020

queries your one query result is

dependent on another another query

result is dependent on another let's

imagine after 10th query there is an

error then the transaction will do the

roll back for

you

in this lesson I'm going to teach you

how to upload the file in

njs nestjs has already created a molter

module if you have used molter in

Express we're going to use the same

logic they have created the molter

module they also have nests platform

Express to

implement file upload feature so this

package provides the typescript typing

to work with multer package which is a

middleware for handling multiart form

data and then we will create our route

Handler for

update they have we're going to use the

Interceptor that's why I use the use use

Interceptor

decator here we have file

Interceptor they have already created

this file Interceptor and you got to

provide the name of your file and here

we will have the upload file decorator

the type should be express. multer do

file that's it then it will log the file

when you send the API request from Front

End application or Postman to upload a

file it will receive the

file so this decorator indicates that

the method should use the f file

Interceptor

Interceptor to handle the file uploads

the string file inside the file

Interceptor decorator refers to the

field name in the request

body now we're going to implement this

file upload

method first of all we have to install

the molter

type I've already attached the started

kit project or if you don't have an sjs

project you can create a brand new

project and start from them start from

there we have

installed uh package now I'm going to

copy the same

code and I'm going to do it here inside

the app

controller

we also need to import file Interceptor

from nestjs platform

Express whenever you need to upload the

file you have to use the use Interceptor

and they have created the file

Interceptor the name of the file here

you will provide the molter options when

you worked with molon if you already

work with molter opt molter package

these are the options are same these

options are same when you work with

molter

package so I'm not going to do it

here and we will have upload file now we

need to test it I'm going to start the

project we need a postman to send the

API

request in terms of

file

so here I'm going to send

request to the upload and we have to

provide the

file select the body and you got to

provide file you can select the file

from here a body and a file and then you

have to select the file

I'm going to use this PNG file you can

choose any

file B request I have to remove this one

now I'm going to send request you can

see a file has created successfully

actually uploaded this is the original

name this is the field file but I want

to save this file some somewhere in my

folder you can create a disc folder and

you can save save that save there to

implement this logic you going to

provide these two

options actually I'm going to copy the

complete

file intercept use

intercept I'm going to copy the complete

use Interceptor now it looks

good so we have to import this package

from disk

storage I think I can get that from

molter

package

molter disktop

storage now it looks

good so it will create the upload folder

for me and here I will have the files

folder now we're going to send the

request to save upload the

file and you can see there is a file

inside the upload folder and inside the

files we have create song mutation. PNG

file you can also add a

validation let's say you can

say I only want

to accept PNG

file how can you add a

validation I can say upload

PNG you can do the validation upload PNG

[Music]

file you can implement the validation

here let me copy the validation

logic they provided the pars file pip

Builder what this pipe Builder will do

this is a custom utility that creates a

pipe for validating uploaded files if

you want to add a maximum size you can

can accept you can also do that but I'm

not going to implement

that we need this

logic inside the upload

file

here I also added an error status code

if error comes it is going to log this

error

message unprocessable

entity now it can accept only the PNG

file type I've applied the pipe to add

PNG validation let's test it

out if I add upload

PNG if I add invalid file what will

happen I'm going to add jpack

I got the

error oh upload Das

PNG I got the error for double to

unprocessable

entity if I provide the valid file which

is

PNG what will happen

can get that from

here this is the PNG

file now the file has uploaded

successfully

here

one more thing we got to return the

message I forgot to return the

message

from here

to also need to upload the

message file uploaded

successfully let's test it out

out this is the PNG

file you should see the

message file uploaded

successfully and you you will see your

file

here in this lesson I'm going to teach

you the concept of custom

decorator if you want to add additional

functionality to a class to a method you

can use custom decorator just like we

did with app module app controller we

use decorator a lot when you look at the

app module here we have used a decorator

this module decorator in the controller

app. controller we have controller

decorator it mean this decorator is

adding an additional functionality to

the app

controller like they are adding

metadata this controller can have

functions attributes all of the

stuff

so you can improve your modularity and

reusability with the help of custom

decorator you can organize code very

easily you can extend Nest functionality

by adding custom

decorator here we're going to use custom

decorator I have a basic simple example

we're going to create our own custom

decorator the user decorator.

this you use pram decorator so I can

apply it on a

parameter and I'm using a function this

function is accepting to argument data

it should be unknown type and we are

getting the execution

context and I can get the request from

this execution context here I'm am

adding a user into the request. user

when you have implemented auth tication

you can create a custom decorator for a

user imagine you can get

this request. user from a Json web token

and Json web token Parts the token and

found the user you can imagine that but

I hardcoded it and return request.

user yeah this is The Decorator Factory

function it takes to parameter data and

the Conta execution

context

and now we're going to create a new user

entity here we have applied a user

decorator let's say this is this is

authenticated route only authenticated

user can access this route so I would

like to get the user so you can use a

user

decorator and the user entity this user

decorator is going to execute this

function and this function will be

executed and it is going to add a user

in the request EST object that's how you

can implement the custom decorator let's

create a new file here I can say a user

decorator

decorator. I'm going to copy my

code user

decorator you can use any name

here I also need to create another

entity this time I'm going to call user.

entity

TS now we're going to apply The

Decorator on a

user do I have a route I can create the

complete route to implement this user

decorator copy this and and paste it

here and we need these two

Imports now we have to test our

application so whenever you need to get

a user inside any function all you need

to do is to apply the decorator

here you can apply The Decorator upload

file you can apply decorator here it

depends on your use

case so my application is

running I'm going to create a new HTTP

client. HTTP file to send API

request can say that find

user only based on

ID we have to send the get

request 3,000 slash user and you got to

provide a user

ID now you can see I got a user so this

decorator a user decorator is calling

the user decorator function and this

function is getting a user or setting a

user to the request object and returning

the

request get decorator is nothing it's

just like a function here in our

case I'm running a function

here uh in this lesson I'm going to

teach you if you want to schedule any

method or any function you can do with

grown

task uh let's uh if you want to schedule

any task let's say you want to run you

want to

calculate the expiry date of a license

let's say your trial version is going to

be expired after 7 days You're Building

this type of SAS application you your

company provides 14 days free trial

and the trial version will be expired

after 14

days what your application will do under

the hood application will run a crown

task it will execute every day in try to

find out the expiry date for the current

user if user has used software for 14

days your Chown to will determine that

and it will send the notification to the

user into your application hey this user

has used 14 days free trial and you may

must have a logic or a code to handle

this

situation maybe you can send the credit

card information to

upgrade so nestjs provide a package to

implement this type of

functionality we're going to we're going

to we're going to install a couple of

packages first you

need next

JS

schedule

and you also need or I can install it

here

types of

grown actually I need a type as a Chone

SE as a Dev dependency let's first

install this package

now we

install the

types or I can use the minus

t and types

Chone NJ has provide a schedule

module from nestjs casual package I have

to import it if you want to use this

package let's import the module schedule

module I have to register it or create

this

module this root module will initialize

this casual

module and it will register any

declarative chrone jobs timeouts

interval that exist assist within your

application right now we did not Define

any Crone task if you have defined Crone

task this for root will initialize all

of your crown

task and registration occurs when the

application when the own application

bootstrap life cycle hook

occurs now we're going to declare some

cras this cronas will run the function

autom automatically we will specify some

specific dat time when this Crown task

will run it depends on your use case do

you want to run this Crown task every

week or every day or every 5 minutes or

every 10 minutes or every hour it

depends on your use use case now we're

going to create a new task

service let's create a new to

service

so let's define our first gr task in

task

service private read only logger it will

log some

message task

service do

name if you want to Define a crown task

you need a decorator in the previous

video I taught you what are the benefits

of decorator like I can extend the

functionality of a function by adding

the Chone

decorator here you will provide your

time path time date something like

that so start start

start you can learn learn more

about this strategy by looking at Crown

task schedu Nest or

npm

you can play around with these timing

settings from this package this package

you can learn more

about how can you set the current dat

stuff like

that here the first star

represent second the second star

represent minute the third star

represent R and the fourth star

represent the day of the month and the

fifth star represent the

month and the last star represent the

week

day did you get that let's say I want to

run the crown task after every 10

seconds so what I want to do I want to

log a simple message after every 10

seconds and say Myron

task I'm going to log a message this do

logger not a

throw this. logger do

debug called when the

current second is

10 let's try to test the

application I have registered the

schedule module here this for will will

initialize this method and we set up the

configuration to run after 10

second let's do

that

you can

see it has run this debug after every 10

seconds

what if I change the setting to

five

now after 5 Seconds it has

executed

e

actually it is running called when the

current second is actually it is wait it

will wait for 1 minute and 5 Seconds

then it will

run wait for 1 minute and 5 Seconds

is

now you can see at

519 and then it has ran after a minute

and on the fifth

second what if I run this cronas after

every

[Music]

second you can see it's running after

every

seconds so I can use

that called when the

crun C call that's

it so it will wait for a minute and a 15

seconds

if you want to do a little bit setting

let's say I want to run every hour at

the start of five uh at the start of the

fifth

minutes but it depends on you how you

want to run

this will

run

after

every

minute

yep after every minute it's

running

this is how you can play around with

crown

task in this lesson you're going to

learn cookies cookies are small pieces

of data dat a server sends to a user

browser while the user is browsing a

website these cookies are stored in user

device and are used to store information

about the user interaction with website

if you look up the Google Chrome you

will see the developer tools and you can

find the application

tab here you will find all of your

cookies if you have

stored we have only single cookie you

can Implement also cookie based

authentication just like we did in

authentication module we saved at

Json web token into a local

storage but if you were if you work with

a local storage or front-end application

you can store your Json web token in

this storage but you can also use a

cookie and you can save your token in

encrypted

format so these are all the use cases of

cookies like most of the time when

you when you access or fetch or look at

the same look at the website or when you

visit the same website again and again

the next time it tries to fetch the data

from your cookies it has saved all of

your

authentication Lo all of your password

in cookies when you go to the Google

password

manager where all of this data is stored

all of this data is stored in your cook

is remember when you look at the history

or let

me you look at the

history if you want to delete all of

your data it will also ask you hey do

you want to do you want to delete all of

your cookie stuff you have data inside

the

cookie so you can save any token inside

the

cookie let me talk about the use cases

of

cookies you can manage user sessions

let's say if you want to expire a user

session after 30 days or after 24

hours you can have that type of logic in

cookie and this cookie will be stored

here inside the application and the

cookies

tab if you have any type of shopping

cart application you can also do a

little bit saving in

the in the cookies let's say a user has

uh add added three to four items to the

checkout and he left the website and

then you can send user hey you left

something a user can see all of his

checkout

items you can do some type of tracking

and analytics you can do authentication

like cookies can help with

authentication and security by storing

tokens or other information that

verifies a user

identity you can use load balancing

State Management and cashing stuff with

cookies now I'm going to implement the

cookies in NS project you got to install

these two packages I have already

installed them

I've already installed in my

package.json file this is the cookie

parser you need and then you also need a

typing for cookie parser go ahead and

install

them all right our next step is to

register a cookie parts sir in main.ts

file this is our main entry file here I

have registered a cookie parser you can

import it as a

star and here if you want to add add

your secret you can do it here or if you

want to

add uh some logic or decode something

like that this is the option from a

cookie package you can go to cookie

parser so this package is similar to

this one this one cookie parser but you

can look at the documentation what type

of options you

have

now our next step is to set the

cookie I'm going to create a new route

to set the cookie and we need a response

from the nestjs comment and response

type from the Express package here I'm

allowing the framework you can set the

cookie I am I'm going to set the cookie

cooking token name encrypted cookie

string something here it's a key value

PA here and I'm sending a message cookie

saved

successfully here here I'm trying to log

all of your cookies and return cookies

in the get route now we need to test the

application when you look the app

controller here let's say I'm want to

set a new

cookie I've already saved that cookie in

my application when you look at the

Local Host colon application tab here we

have the cookie let's say I want to set

a new cookie it should be let's say a

user

token or authenticated token something

like that JWT

or

JWT encrypt something like

that yes jw.

iio so what I want to do I want to

so

let's can I do

that let's add this payload

here or you can say I want to add a user

ID let's

say

token I'm going to add a user

ID

let's say a mongod DB

ID or you can say user

ID so let's send the request from our

browser to first set the

cookie so I can set the request please

set the cookie cookie saved successfully

and you can see your user ID here this

one but it did not

encrypt but it did not save as

encrypted you have to save your

encrypted value here let's say I'm going

to copy this

token and you got to paste it

[Music]

here now I have an encrypted

value so cookie saved successfully what

if I try to get the

cookie get all of my

cookie it is going to give me the user

ID and cookie token

name that's how if you want to implement

cookie based authentication you can do

that if you want to implement High

intent intensive task then you need

cues High intensive task

mean sending emails generating reports

processing images or any task that can

be offloaded from the main application

flow with the help of cues you can

manage in process task in the background

without blocking the main application

execution

so you can use cues in task

generation when you you identify task

that can be processed

asynchronously let's consider sending an

email after a user register instead of

sending email directly with the

registration endpoint you can push the

task of a sending email to a

queue

so this task is executed in the

background separate from the main

application thread this this ensure that

the main application remains responsive

and does not get blogged by the time

consuming

tasks so if you have highly CPU

intensive task then you can use

qes let's dive into the implementation

of cues in nestjs nestjs provided the

bull package they have written their own

implementation by using the original

bull package you have to install the

package

first I'm going to install the nestjs

bll I also need to install npm B npm

install B the simple bull

package nextjs pull is using the redish

under the

hood so you need radish caching

Library make sure you have Docker in

your

system we're going to use Docker to pull

redish image I'm not going to install

redish separately so that's why I'm

going to use docker

now let's create a new module our

application what we want to do we're

going to create a fake implementation to

convert do wave audio file to MP3 we're

going to write fake implementation let's

say you have a use case where you want

to convert do wave file to MP3 or you

have an application where you need this

functionality you want to convert video

MP4 to MP3 in that case you need a

q

let's create a new audio module we're

going to write implementation here to

convert do wave file to

MP3 then we need a docket

compose we're going to use redish

image

now we're going to set up Ries in the

docket compose file let's create a new

file inside the root

directory I'm going to do it here docket

compos

yl let's rename it to

yl so we have to in start the docker

compose my Docker is running

now let's install Docker

compose

up it will pull the redish image from

the docker Hub but I have already pulled

Docker radish

image so my

radish server has

started I think I've already installed

another extension to work with redes if

you want you can install

that here you can see the redis I have

installed this one database manager for

my SQL Maria B post sqlite and redis

here you will see the database if I try

to create a connection for the

redes Local Host

6379 that's my port so I can connect now

now you will

see all of my

databases so this is my current or the

latest I'm going to delete the rest of

the

other now I have the empty let's remove

everything let's

connect so I have the audio

que so get rid of this

one now we have the empty data

SP now we need to

register a bull

module so in the app

module I'm going to register it

here your module

and I'm going to do it

here make sure you imported a bull

module bull

module

import from Nest

CHS SGS Bull and bull

module so I'm going to open a new tab to

run my

application next we need to register a

queue inside the audio module you will

find the audio module here so we got a

register it

here make sure you imported the bull

module and I'm going to copy

that and let me paste it

here so this register Q This method is

used to register a queue with your

within your application it takes an

optional object as an argument to

configure the que we have provided the

name of our Q audio

q and this is the name you will see the

name here

here it should be the audio Q this one

where is my redish

yep you will see the audio queue

here let's move forward now we're going

to create a convert end point I'm going

to copy

that into audio

controller and

I'm so we have audio Q let's imagine we

would like to convert v file into MP3

this is my I'm just writing the fake

implementation we are not writing the

exact logic to convert the file but you

can do that this is just a file name

this is an optional object so this will

add a new entry inside the

Q so we have injected the audio q i got

this Q from from The Bu package the type

now we need a processor to process the

queue let's define a new audio

processor audio.

processor. it would be a service or

provider so we got to register it here

inside the

providers

AIO

processor

so

here when you want to process this when

the application wants to process it is

going to call this handle convert this

job will take this argument as a job

here inside the audio

processor so I'm just trying to do the

log here let's run the

application to convert W file to m B3 we

have to send the convert request

so in the HTTP

client I'm going to send the post

request convert let's say dot v file to

MP3

post HTTP Local Host Callum 3000 SL

audio SL convert I don't need to provide

any argument but if you want to provide

argument or or request body you can do

that now you can see it has run

successfully I got this message starting

wave file inside the audio

processor here starting start converting

v file to MP3 and I got the object which

is sample. W file which which I have

passed here whatever you pass here it

will be received here inside the job.

data and finally it has completed this

one if you have any type of logic to

convert P file to MP3 you will Implement

here

here but what if I look up the

database do you have this

one convert yep you can see the bull and

we we have the audio Q this is our

message I can show

you here you can see the name is

convert which we named here the convert

this one q key key is here

convert

convert and the data is sample. W file

and all of these metad data

what if I provide additional data let's

say ID which is one so it is going to

save also

ID let's run the request you can see I

got the file and

ID and Let me refresh

it

I'm going to

connect uh you can

see file sample

do wave and you can see the ID the name

is convert and the audio CU which is we

have named here here inside the audio

module this is the audio

Q in this lesson I'm going to teach you

the event

emitter in nextjs event emitor is a

mechanism that allows different parts of

your application to communicate with

each other and even driven

approach so you can learn more about you

can do communication between module

Services components or classes under the

hood nestjs uses event emiter to

collaborate with these services and

modules and

components so an event emitter works

with Publisher and subscriber pattern if

you heard about this design pattern or

you have used this design

pattern now we're going to talk about

some practical use cases of event

emitter you can do module communication

you can send the notification

system we're going to use this use

case in the previous video we have

converted wave file to

MP3 now I want to convert I want to send

the notification if the file has

successfully converted we need to send

the notification to the user we can also

use from for Real Time updates if you

have any plugin syst system you can do

with the help of event emitter you can

achieve logging and monitoring you can

do error handling and Reporting this one

is also useful you can Implement in user

authentication and

authorization for example authorization

service could emit an event when user

logs in and other parts of application

can respond Accord accordingly let's say

user has logged after 10 days your you

can your system or your application can

have

notification you can also Implement in

the caching and management in our case

we're going to take example from our

previous

example let's say you want to send the

notification when w file converts

successfully into MP3 format you can use

event emitter to send the

notification

you got to install the package first

nestjs event

emitter and Next Step you got to

register the event emitter in the app

module let me change my

Branch

here

event emitter Pro

we got to create install event emitter

again because I was in a different

branch let's install

it we have event

emitter let's register it in the app

module I'm going to do it here

we have to import the event emiter

module I have to import it manually

event emitter

module from

nestjs event

emiter that looks good we have

registered the event emitter module this

will register all of your event listener

or or create all of your event listener

we will have audio converted

listener it's a service it's a

provider this we have just a method it

will accept the event and the audio

event we will create the type this is

the name of the listener or the name of

the event that's why I used on event

here when you emit the event this audio

converted event this function will be

called we're going to emit this event in

the handle convert in the previous video

we used this method to convert fave into

MP3 so when you emit this event this

method will be

called so you can have any type of logic

here maybe you will have an email

service and your email service will have

a method to send email let's create a

new file I'm going to copy all of the

code this is a provider we're going to

in we're going to create inside

the

audio

converted what's the name of the file

audio converted

listener I can say audio do

converted or you can say audio

converted

listener. so we have this

file we did not create this type let's

create this

type in audio

folder I can say

audio actually we can do it in an events

folder we're going to store all of the

types

audio converted

event. it's nothing it's just a type for

types typescript

class it looks good make sure you

register your provider in the audio

module so audio

converted

listener

now we need to import we need to emit

this

event in your handle convert we have

done it in the

processor while converted successfully

and you can send a

message make sure you

have import or inject event

emitter event emitter

event emitter

2 from njs event emitter

package

njs event

emiter

oops event emiter I don't know why they

use two so I'm going to use the same

stuff two event emitter

to and we have emit this

event this

one now we have to test the application

let's run the

application I think do I need a

Docker let's run the

application yes I need a

Docker let's install the uh let's start

the docker first because we were using

redes when we were building this Q so

this Q is dependent on bull module is

dependent on

rades let me start my

Docker now my Docker is running now

let's run the application to test this

event

emitor we have to send the API request

to convert fa file to

MP3 it should log the message actually

it should run this

event this

meth

let's send the

request I'm not able to send the request

why saying

waiting I think I did something wrong

here look at the audio

processor or audio

controller

wa I think it is not calling this method

or emitting this

method emitting this IM

event oh I think we did not stop part

that is

server let's do it I'm going to send the

request connect with

r

so it has X executed

successfully and I got the message

notification has sent to the user that

file is converted

successfully so I also loged the

event that looks good we have

successfully

achieved our desired use

case here it has emited the event I also

passed a data object from the Q job.

data which we were sending from here so

I received the same

object inside the event

listener here I received the same event

here and here I locked the event the

first one is the event and the message

notification has sent to user

successfully this is how you will

Implement event emitter in

nestjs in this lesson I'm going to teach

you the streaming in

sjs streaming is the process of sending

or receiving data in small chunks called

streams rather than sending or receiving

the entire data at once the concept is

based on stream API in

nodejs and is utilized for more

efficient data handling especially when

dealing with large amounts of data such

as files Network request or realtime

data

Transmissions you can use streaming for

file upload and file download you can do

realtime communication if you have to

build a media streaming type application

like Netflix then you need streaming

API API responses reading and writing

from

stream when processing data from sources

that generate data

incrementally such as reading log file

or parsing large XML or Json

documents you can do some data

aggregation server sent events database

operations proxy servers all of these

practical use cases of streaming in this

video I'm just showing you how to

download a file with the help of

streaming we need a nest controller a

file controller here I will

specify a a a method it will download

the file from this crun project as a

package.json file it is going to save in

my computer this is another customized

way to download the

file when you download the file with

this method it will download the exact

package.json file here it will not

download with extension only text file

let me show you the difference between

them let's create a new

controller open the file controller let

me import some

dependencies and we need to use this

method to download the file I'm going to

create a new method here let's run the

application let's try to send the

request to the

file file we have the endpoint file and

the stream

file file and stream

file now it is going to

download the package.json

file you can

see it is giving just only a stream file

it did not download with package.json

file if I open the file you will see it

is nothing more it's just a simple text

file in a Json

format but we going to we want to

download the exact Json file you can do

the same stuff when you down when you

want to download

images or video you have to specify here

the content type should be video or

audio it depends on your use case and

you also can provide the name of your

file just like we did the package.json

file you have to do it content dispo dis

disposition now we're going to copy the

same part method and place it

here it will return a streamable file I

have created the stream by you joining

the path which is this one I'm referring

to package.json file

file and finally I'm setting the

response by setting application Json my

file name would be this one act as the

attachment and finally it is going to

return the streamable file now if I go

to this

endpoint file and/ stream file

customize what will

happen now it is going to do stream file

customize. Json on not not it should be

Json now it is going to see you will see

the package.json file I already

downloaded the package.json file when we

were when I was practicing this I can

replace that you will see the

package.json

file I have opened the file in my

Mozilla

Firefox you can see your the package

Json file we have scripts we have all

the dependencies and we have the dev

dependencies this is how you can

download any file if you have images you

can specify your image format or you can

name the file name or your image file

name you can also set your image content

type in this lesson you're going to

learn this session in

sjs session refers to the concept of

maintaining stateful data between

consecutive request from the same client

a session allows you to send allows you

to store and retrieve user specific

information on the server server on the

server across multiple request typically

using cookies to identify the session if

you have used session based

authentication in your project the

concept is

same you can use session to maintain the

authentication state of a user when a

user log in logs in session can be

created with their authen authentication

data and subsequent request can be

authenticated based on the session you

can use session in authorization user

preferences shopping cards user tracking

caching

personalization and form data

persistence we going to use the express

session let's install these two

packages I have already installed in my

package.json

file

session Express session and the next

package you need type of Express session

then our next step is to register a

middleware when you go to main.ts you

got to register it

here AB do session make make sure you

import your session from the express

session you can use any secret key you

can also set resave you can read the

documentation of resave what this resave

is doing you can also read the

documentation of save

uninitialized you can find documentation

here from the express

session when you check a save or

resave here you will find the

documentation

uninitialized initialized you can also

find the documentation of

uninitialized next we have app

controller here I'm going to create a

simple route to login let's say uh a

user wants to log in when logged in

successfully we have verified the user

from the database then you can set the

user into the session I have set the

object ID and the username and when

later user wants to access his profile

he can do that because we have saved the

user in the session so here if there is

a user in the session it is going to

return user else not logged in you can

test it simple by sending the login

request it is saying a user has logged

in just like we did just like it did if

I said if I try to retrieve the profile

it is going to give me the profile

because we have set that user when we

were logged in this one now I got this

hello with the user and the name this is

how uh if you use Json web token we

basically stored a Json web token in the

storage but if you want to use session

based authentication on front end you

can do that