01 controller

Controller responsibility is to handle the request and response, and delegate the business logic to the service.

Routing

Controller will be mapped to the route based on the @Controller decorator.

Create a controller named cats.

nest g controller cats

// src/cats/cats.controller.ts
import { Controller, Get } from '@nestjs/common';

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

The route will be /cats with GET method.

@Controller('cats')
export class CatsController {
  @Get('breed')
  findBreed(): string {
    return 'This action returns breed cats';
  }
}

The route will be /cats/breed with GET method.

Request object

Nest.js provides a set of decorators to handle the request.

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

@Controller('cats')
export class CatsController {
  @Get()
  findAll(@Req() req: Request): string {
    return 'This action returns all cats';
  }
}

Needs install @types/express

Decorators	Description
@Req()	req object
@Res()	res object
@Next()	next function
@Session()	req.session
@Headers(name?: string)	req.headers/req.headers[name]
@Param(key?: string)	req.params/req.params[key]
@Query(key?: string)	req.query/req.query[key]
@Body(key?: string)	req.body/req.body[key]
@Ip()	req.ip
@HostParam()	req.hosts

Resources

Create a resource use POST method.

// src/cats/cats.controller.ts
import { Controller, Get, Post } from '@nestjs/common';

@Controller('cats')
export class CatsController {
  @Post()
  create(): string {
    return 'This action adds a new cat';
  }
}

The route will be /cats with POST method.

The decorators with the HTTP method are:

• @Get()
• @Post()
• @Put()
• @Delete()
• @Patch()
• @Options()
• @Head()
• @All() | All HTTP methods

Route wildcards

* matches any characters.

  @Get('cats/*')
  findAll(): string {
    return 'This route matches /cats/*';
  }

This route will match /cats, /cats/1, /cats/1/2, /cats/abc, etc.

Status code

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

  @Post()
  @HttpCode(204)
  create(@Res() res: Response): string {
    return ;
  }

Response headers

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

  @Post()
  @Header('Cache-Control', 'none')
  create(): string {
    return 'This action adds a new cat';
  }

Redirection

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

  @Get()
  @Redirect('https://nestjs.com') // or @Redirect('https://nestjs.com', 301)

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

  @Get()
  @Redirect('https://nestjs.com', 301)
  getDocs(@Query('version') version: string): string {
    return {
      url: `https://docs.nestjs.com/${version}`,
    };
  }

Route parameters

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

@Get(':id')
findOne(@Param('id') id: string): string {
  return `This action returns a #${id} cat`;
}

The route will be /cats/:id with GET method.

Routes with parameters should be declared after any static paths.