NestJS - A progressive Node.js framework

const express = require('express');
const app = express();

app.get('/', (req, res) => {
  res.send('hello world');
});

app.listen(3000);

@Controller
@RequestMapping("/hello")
public class HelloController { 
   
   @RequestMapping(method = RequestMethod.GET)
   public String printHello(ModelMap model) {
      model.addAttribute("message", "Hello Spring MVC Framework!");
      return "hello";
   }

}
public class HomeController : Controller
{
   [Route("")]
   [Route("Home")]
   [Route("Home/Index")]
   public IActionResult Index()
   {
      return View();
   }
   [Route("Home/About")]
   public IActionResult About()
   {
      return View();
   }
   [Route("Home/Contact")]
   public IActionResult Contact()
   {
      return View();
   }
}
from wsgiref.simple_server import make_server
from pyramid.config import Configurator
from pyramid.response import Response
from pyramid.view import view_config


@view_config(
    route_name='home'
)
def home(request):
    return Response('Welcome!')

if __name__ == '__main__':
    with Configurator() as config:
        config.add_route('home', '/')
        config.scan()
        app = config.make_wsgi_app()
    server = make_server('0.0.0.0', 6543, app)
    server.serve_forever()

Philosophy

Parts

Getting Started

$ npm i -g @nestjs/cli
$ nest new project-name
├── README.md
├── nest-cli.json
├── nodemon-debug.json
├── nodemon.json
├── package-lock.json
├── package.json
├── src
│   ├── app.controller.spec.ts
│   ├── app.controller.ts
│   ├── app.module.ts
│   ├── app.service.ts
│   └── main.ts
├── test
│   ├── app.e2e-spec.ts
│   └── jest-e2e.json
├── tsconfig.build.json
├── tsconfig.json
└── tslint.json
import { NestFactory } from '@nestjs/core';
import { AppModule } from './app.module';

async function bootstrap() {
  const app = await NestFactory.create(AppModule);
  await app.listen(3000);
}
bootstrap();

main.ts

Modules

Module

import { Module } from '@nestjs/common';
import { AppController } from './app.controller';
import { AppService } from './app.service';

@Module({
  imports: [],
  controllers: [AppController],
  providers: [AppService],
})
export class AppModule {}

Controllers

Controller

import { Controller, Get } from '@nestjs/common';

@Controller('cats')
export class CatsController {
  @Get()
  findAll() {
    return 'This action returns all cats';
  }
}

@Injectable()

Service

import { Injectable } from '@nestjs/common';

@Injectable()
export class AppService {
  getHello(): string {
    return 'Hello World!';
  }
}

Controller

import { Controller, Get } from '@nestjs/common';
import { AppService } from './app.service';

@Controller()
export class AppController {
  constructor(private readonly appService: AppService) {}

  @Get()
  getHello(): string {
    return this.appService.getHello();
  }
}

Middleware

Middleware

import { 
  Injectable, 
  NestMiddleware, 
  MiddlewareFunction 
} from '@nestjs/common';

@Injectable()
export class LoggerMiddleware implements NestMiddleware {
  resolve(...args: any[]): MiddlewareFunction {
    return (req, res, next) => {
      console.log('Request...');
      next();
    };
  }
}

Middleware

import { 
  Module, 
  NestModule, 
  MiddlewareConsumer 
} from '@nestjs/common';
import { 
  LoggerMiddleware 
} from './common/middlewares/logger.middleware';
import { CatsModule } from './cats/cats.module';

@Module({
  imports: [CatsModule],
})
export class ApplicationModule implements NestModule {
  configure(consumer: MiddlewareConsumer) {
    consumer
      .apply(LoggerMiddleware)
      .forRoutes('cats');
  }
}

Errors

@Post()
async create(@Body() createCatDto: CreateCatDto) {
  throw new HttpException({
    status: HttpStatus.FORBIDDEN,
    error: 'This is a custom message',
  }, 403);
}

Pipes


@Post()
@UsePipes(new JoiValidationPipe(createCatSchema))
async create(@Body() createCatDto: CreateCatDto) {
  this.catsService.create(createCatDto);
}

Pipes

import { 
  PipeTransform, Injectable, ArgumentMetadata 
} from '@nestjs/common';

@Injectable()
export class ValidationPipe implements PipeTransform {
  transform(value: any, metadata: ArgumentMetadata) {
    return value;
  }
}

Guards

Guards


@Controller('cats')
@UseGuards(RolesGuard)
export class CatsController {}

Guards

import { 
  Injectable, CanActivate, ExecutionContext 
} from '@nestjs/common';
import { Observable } from 'rxjs';

@Injectable()
export class AuthGuard implements CanActivate {
  canActivate(
    context: ExecutionContext,
  ): boolean | Promise<boolean> | Observable<boolean> {
    const request = context.switchToHttp().getRequest();
    return validateRequest(request);
  }
}

Interceptors

Interceptors

@UseInterceptors(LoggingInterceptor)
export class CatsController {}

Interceptors

import { 
  Injectable, NestInterceptor, ExecutionContext 
} from '@nestjs/common';
import { Observable } from 'rxjs';
import { tap } from 'rxjs/operators';

@Injectable()
export class LoggingInterceptor implements NestInterceptor {
  intercept(
    context: ExecutionContext,
    call$: Observable<any>,
  ): Observable<any> {
    console.log('Before...');

    const now = Date.now();
    return call$.pipe(
      tap(() => console.log(`After... ${Date.now() - now}ms`)),
    );
  }
}

Testing

$ npm i --save-dev @nestjs/testing
import { CatsController } from './cats.controller';
import { CatsService } from './cats.service';

describe('CatsController', () => {
  let catsController: CatsController;
  let catsService: CatsService;

  beforeEach(() => {
    catsService = new CatsService();
    catsController = new CatsController(catsService);
  });

  describe('findAll', () => {
    it('should return an array of cats', async () => {
      const result = ['test'];
      jest.spyOn(catsService, 'findAll').mockImplementation(() => result);

      expect(await catsController.findAll()).toBe(result);
    });
  });
});
import { Test } from '@nestjs/testing';
import { CatsController } from './cats.controller';
import { CatsService } from './cats.service';

describe('CatsController', () => {
  let catsController: CatsController;
  let catsService: CatsService;

  beforeEach(async () => {
    const module = await Test.createTestingModule({
        controllers: [CatsController],
        providers: [CatsService],
      }).compile();

    catsService = module.get<CatsService>(CatsService);
    catsController = module.get<CatsController>(CatsController);
  });

  describe('findAll', () => {
    it('should return an array of cats', async () => {
      const result = ['test'];
      jest.spyOn(catsService, 'findAll').mockImplementation(() => result);

      expect(await catsController.findAll()).toBe(result);
    });
  });
});
import { Test, TestingModule } from '@nestjs/testing';
import * as request from 'supertest';
import { AppModule } from './../src/app.module';

describe('AppController (e2e)', () => {
  let app;

  beforeEach(async () => {
    const moduleFixture: TestingModule = await Test.createTestingModule({
      imports: [AppModule],
    }).compile();

    app = moduleFixture.createNestApplication();
    await app.init();
  });

  it('/ (GET)', () => {
    return request(app.getHttpServer())
      .get('/')
      .expect(200)
      .expect('Hello World!');
  });
});

Microservices

$ npm i --save @nestjs/microservices
import { Controller } from '@nestjs/common';
import { MessagePattern } from '@nestjs/microservices';

@Controller()
export class MathController {
  @MessagePattern({ cmd: 'sum' })
  sum(data: number[]): number {
    return (data || []).reduce((a, b) => a + b);
  }
}
constructor() {
  this.client = ClientProxyFactory.create({
    transport: Transport.TCP
  });
}

@Get()
call(): Observable<number> {
  const pattern = { cmd: 'sum' };
  const payload = [1, 2, 3];
  return this.client.send<number>(pattern, payload);
}



import { NestFactory } from '@nestjs/core';
import { Transport } from '@nestjs/microservices';
import { ApplicationModule } from './app.module';

async function bootstrap() {
  const app = await NestFactory.createMicroservice(ApplicationModule, {
    transport: Transport.TCP,
  });
  app.listen(() => console.log('Microservice is listening'));
}
bootstrap();

Recipes

$ npm install --save @nestjs/swagger
import { NestFactory } from '@nestjs/core';
import { SwaggerModule, DocumentBuilder } from '@nestjs/swagger';
import { ApplicationModule } from './app.module';

async function bootstrap() {
  const app = await NestFactory.create(ApplicationModule);

  const options = new DocumentBuilder()
    .setTitle('Cats example')
    .setDescription('The cats API description')
    .setVersion('1.0')
    .addTag('cats')
    .build();
  const document = SwaggerModule.createDocument(app, options);
  SwaggerModule.setup('api', app, document);

  await app.listen(3001);
}
bootstrap();
@Post()
async create(@Body() createCatDto: CreateCatDto) {
  this.catsService.create(createCatDto);
}


class CreateCatDto {
  @ApiModelProperty()
  readonly name: string;

  @ApiModelProperty()
  readonly age: number;

  @ApiModelProperty()
  readonly breed: string;
}

Passport.js

$ npm install --save @nestjs/passport passport passport-http-bearer
import { AuthGuard } from '@nest/passport';

@Get('users')
@UseGuards(AuthGuard('bearer'))
findAll() {
  return [];
}
import { Strategy } from 'passport-http-bearer';
import { PassportStrategy } from '@nestjs/passport';
import { Injectable, UnauthorizedException } from '@nestjs/common';
import { AuthService } from './auth.service';

@Injectable()
export class HttpStrategy extends PassportStrategy(Strategy) {
  constructor(private readonly authService: AuthService) {
    super();
  }

  async validate(token: string) {
    const user = await this.authService.validateUser(token);
    if (!user) {
      throw new UnauthorizedException();
    }
    return user;
  }
}
$ npm install --save @nestjs/typeorm typeorm mysql
import { Module } from '@nestjs/common';
import { TypeOrmModule } from '@nestjs/typeorm';

@Module({
  imports: [
    TypeOrmModule.forRoot({
      type: 'mysql',
      host: 'localhost',
      port: 3306,
      username: 'root',
      password: 'root',
      database: 'test',
      entities: [__dirname + '/**/*.entity{.ts,.js}'],
      synchronize: true,
    }),
  ],
})
export class ApplicationModule {}
import { 
  Entity, Column, PrimaryGeneratedColumn 
} from 'typeorm';

@Entity()
export class Photo {
  @PrimaryGeneratedColumn()
  id: number;

  @Column({ length: 500 })
  name: string;

  @Column('text')
  description: string;

  @Column()
  filename: string;

  @Column('int')
  views: number;

  @Column()
  isPublished: boolean;
}
import { Injectable, Inject } from '@nestjs/common';
import { InjectRepository } from '@nestjs/typeorm';
import { Repository } from 'typeorm';
import { Photo } from './photo.entity';

@Injectable()
export class PhotoService {
  constructor(
    @InjectRepository(Photo)
    private readonly photoRepository: Repository<Photo>,
  ) {}

  async findAll(): Promise<Photo[]> {
    return await this.photoRepository.find();
  }
}
$ npm install --save @nestjs/mongoose mongoose
import { Module } from '@nestjs/common';
import { MongooseModule } from '@nestjs/mongoose';

@Module({
  imports: [MongooseModule.forRoot('mongodb://localhost/nest')],
})
export class ApplicationModule {}
import * as mongoose from 'mongoose';

export const CatSchema = new mongoose.Schema({
  name: String,
  age: Number,
  breed: String,
});
import { Model } from 'mongoose';
import { Injectable } from '@nestjs/common';
import { InjectModel } from '@nestjs/mongoose';
import { Cat } from './interfaces/cat.interface';
import { CreateCatDto } from './dto/create-cat.dto';

@Injectable()
export class CatsService {
  constructor(@InjectModel('Cat') private readonly catModel: Model<Cat>) {}

  async create(createCatDto: CreateCatDto): Promise<Cat> {
    const createdCat = new this.catModel(createCatDto);
    return await createdCat.save();
  }

  async findAll(): Promise<Cat[]> {
    return await this.catModel.find().exec();
  }
}

Security

$ npm i --save helmet
$ npm i --save csurf
$ npm i --save express-rate-limit
import * as csurf from 'csurf';
import * as helmet from 'helmet';
import * as rateLimit from 'express-rate-limit';

// somewhere in your initialization file
app.use(helmet());
app.use(csurf());
app.use(rateLimit({
  windowMs: 15 * 60 * 1000, // 15 minutes
  max: 100 // limit each IP to 100 requests per windowMs
}));

Questions? Ideas?

Thank you

NestJS

By Andrey Kucherenko

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