nest学习（一）

1. 核心文件目录

    src
        -app.controller.ts
        -app.module.ts
        -main.ts
   

2. 控制器controller

    import { Controller, Get, Res, Req, HttpStatus } from '@nestjs/common';
   
    @Controller()
    export class AppController {
   
        @Get()
        getHello(@Res() res) {
            res.status(HttpStatus.CREATED).send();
        }
        // async/await
        @Get()
        async getHello(@Res() res): Promise<any[]> {
            res.status(HttpStatus.OK).json([]);
        }
    }
   

3. 路由router

   在controller修饰器中定于路由

    @Controller(‘cat’)
    // localhost:3000/cat
   

   路由器通配符

    ?, +, *, -, ., and ()
   

   路由参数

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

4. 装饰器decorator

   1. 参数
      • @Request() req
      • @Response() res
      • @Next() next
      • @Session() req.session
      • @Param(param?: string) req.params / req.params[param]
      • @Body(param?: string) req.body / req.body[param]
      • @Query(param?: string) req.query / req.query[param]
      • @Headers(param?: string) req.headers / req.headers[param]
   2. 请求方法
      • @Put(),
      • @Delete(),
      • @Patch(),
      • @Options(),
      • @Head(),
      • @All()
   3. 其他

      • @HttpCode(204) //状态码

      • @Header(‘Cache-Control’, ‘none’) // 请求头

      • @Injectable() // 注入，用于provider

      • @Optional() // 表明不一定要传递该变量或对象等。。。

           @Injectable()
           export class HttpService<T> {
               constructor(
                   @Optional() @Inject('HTTP_OPTIONS') private readonly httpClient: T,
               ) {}
           }
        

      • @Inject(‘HTTP_OPTIONS’) //基于属性的注入

      • @Module() //模块

5. 模型Model

    export class CreateCatDto {
        readonly name: string;
        readonly age: number;
        readonly breed: string;
    }
   
    @Post()
    async create(@Body() createCatDto: CreateCatDto) {
        return 'This action adds a new cat';
    }
   

6. provider

    // 在cats.service.ts文件中
    import { Injectable } from '@nestjs/common';
    import { Cat } from './interfaces/cat.interface';
   
    @Injectable()
    export class CatsService {
        private readonly cats: Cat[] = [];
   
        create(cat: Cat) {
            this.cats.push(cat);
        }
   
        findAll(): Cat[] {
            return this.cats;
        }
    }
    // 在cats.controller.ts文件中
    import { Controller, Get, Post, Body } from '@nestjs/common';
    import { CreateCatDto } from './dto/create-cat.dto';
    import { CatsService } from './cats.service';
    import { Cat } from './interfaces/cat.interface';
   
    @Controller('cats')
    export class CatsController {
        constructor(private readonly catsService: CatsService) {}
   
        @Post()
        async create(@Body() createCatDto: CreateCatDto) {
            this.catsService.create(createCatDto);
        }
   
        @Get()
        async findAll(): Promise<Cat[]> {
            return this.catsService.findAll();
        }
    }