Configuration and use of controllers and routes in nestjs

About Nest controller

1 ) The function of the controller

• Nest The controller layer in is responsible for handling incoming requests , And return the response to the client
• The purpose of the controller is to receive application specific requests . The routing mechanism controls which controller receives which requests
• Usually , Each controller has multiple routes , Different routes can perform different operations

2 ) The creation of the controller

• be based on cli Create the controller : $ nest g controller about
• One controller corresponds to one class class , And usually use @Controller To decorate

Example ：

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

@Controller('about')
export class AboutController {
    }

• After executing the create command , Not only does it generate a src/about Catalog , Directory is 2 Controller files
• Namely ：about.controller.spec.ts and about.controller.ts
• The main module has also been updated ：/src/app.module.ts, That is, the controller module is automatically injected
• We continue to write business logic

Example ：

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

@Controller('about')
export class AboutController {
    
  // about
  @Get()
  index():string {
    
    //  Notice the top index You can name it as you like , Not necessarily index
    return ' I am a about page ';
  }

  //  Notice in the decorator , Do not use semicolons ;
  // /about/more
  @Get("more")
  getMore():string {
    
    //  Notice the top index You can name it as you like , Not necessarily index
    return ' I am a about More pages for ';
  }
}

• When the request handler returns JavaScript Object or array , It will be automatically serialized to JSON
• however , When it returns a string ,Nest Instead of serializing it, just send a string
• This makes response processing simple ： Just return the value ,Nest Take care of the rest

3 ） Creation of other modules

• $ nest g --help You can view which modules can be created

About Nest route

1 ) summary

• Routing is another name for interface address , And routing and controller are inseparable
• The controller is used to respond to routing requests , In writing , We usually code based on decorator patterns

2 ） The function of ornaments

• The extension class , Method , attribute , And the function of parameters
• Provided by default ：HTTP Decorator of the request method @Put() 、@Delete()、@Patch()、 @Options()、 @Head() and @All()
• It's very good RESTful Supported , Again , For request parameters , There are also some built-in decorators

@Request()                      req
@Response()                     res
@Next()                         next
@Session()                      req.session
@Param(key?: string)            req.params / req.params[key]
@Body(key?: string)             req.body / req.body[key]
@Query(key?: string)            req.query / req.query[key]
@Headers(name?: string)         req.headers / req.headers[name]

3 ) Examples of decorators

import  {
     Controller, Get, Post, Query, Request, Body }  from '@nest/common';

@controller('cart')
export class CartController {
    
  @Get()
  index() {
    
    return 'Shopping Cart';
  }

  @Get('add')
  addCart(@Query() query) {
    
    console.log(query);
    return 'Add To Cart';
  }

  @Get('edit')
  editCart(@Request() req) {
    
    console.log(req.query);
    return req.query;
  }

  @Post('create')
  create(@Body body) {
    
    console.log(body);
    return 'create'
  }
}

3 ) Configuration of dynamic routing

import  {
     Controller, Get, Post, Param, Query }  from '@nest/common';

@controller('order')
export class OrderController {
    
  @Post('add')
  addOrder(@Query('id') id) {
    
    // order/add?id=123
    console.log('id: ', id)
    return id;
  }

  @Get(':id')
  index(@Param() param) {
    
    // order/123
    console.log(param);
    return ' Current page parameters '
  }
}

• Be careful , If the routing form is roughly the same , You need to pay attention to the search order , such as
• order/123 and order/add These two kinds of , Need to put add Put it on top , Avoid mismatches

4 ) Fuzzy matching of dynamic routing

import  {
     Controller, Get, Post, Param, Query }  from '@nest/common';

@controller('order')
export class OrderController {
    

  @Get('xx*yy')
  vagueMatch() {
    
    console.log('vague match');
    return ' Fuzzy matching ';
  }

  @Post('add')
  addOrder(@Query('id') id) {
    
    // order/add?id=123
    console.log('id: ', id)
    return id;
  }

  @Get(':id')
  index(@Param() param) {
    
    // order/123
    console.log(param);
    return ' Current page parameters '
  }
}

• It is also necessary to pay attention to the sequence