Nest 项目小实践之增删改查

这一节看这部分

生成 book 模块

nest g resource book

book.controller.ts 更新下

import { Controller, Get, Post, Body, Patch, Param, Delete, Put } from '@nestjs/common';
import { BookService } from './book.service';
import { CreateBookDto } from './dto/create-book.dto';
import { UpdateBookDto } from './dto/update-book.dto';

@Controller('book')
export class BookController {
  constructor(private readonly bookService: BookService) {}

  @Get('list')
  async list() {
    return this.bookService.list();
  }

  @Get(':id')
  async findById(@Param('id') id: string) {
    return this.bookService.findById(+id);
  }

  @Post('create')
  async create(@Body() createBookDto: CreateBookDto) {
    return this.bookService.create(createBookDto);
  }

  @Put('update')
  async update(@Body() updateBookDto: UpdateBookDto) {
    return this.bookService.update(updateBookDto);
  }

  @Delete('delete/:id')
  async delete(@Param('id') id: string) {
    return this.bookService.delete(+id);
  }
}

创建 book/dto/create-book.dto.ts

import { IsNotEmpty } from "class-validator";

export class CreateBookDto {
    @IsNotEmpty({ message: '书名不能为空' })
    name: string;

    @IsNotEmpty({ message: '作者不能为空' })
    author: string;

    @IsNotEmpty({ message: '描述不能为空' })
    description: string;

    @IsNotEmpty({ message: '封面不能为空' })
    cover: string;
}

book/dto/update-book.dto.ts

import { IsNotEmpty } from "class-validator";

export class UpdateBookDto {
    @IsNotEmpty({ message: 'id 不能为空' })
    id: number;

    @IsNotEmpty({ message: '书名不能为空' })
    name: string;

    @IsNotEmpty({ message: '作者不能为空' })
    author: string;

    @IsNotEmpty({ message: '描述不能为空' })
    description: string;

    @IsNotEmpty({ message: '封面不能为空' })
    cover: string;
}

book.service.ts 更新使用到的方法

import { UpdateBookDto } from './dto/update-book.dto';
import { CreateBookDto } from './dto/create-book.dto';
import { Injectable } from '@nestjs/common';

@Injectable()
export class BookService {

    list() {

    }

    findById(id: number) {

    }

    create(createBookDto: CreateBookDto) {

    }

    update(updateBookDto: UpdateBookDto) {

    }

    delete(id: number) {
        
    }
}

和 User 一样 book 信息也先存储在 json 里面 在 BookModule 里引入

更新 book.service.ts 读取文件里 books 的内容，做下增删改，然后再写入文件

import { UpdateBookDto } from './dto/update-book.dto';
import { CreateBookDto } from './dto/create-book.dto';
import { BadRequestException, Inject, Injectable } from '@nestjs/common';
import { DbService } from 'src/db/db.service';
import { Book } from './entities/book.entity';

function randomNum() {
  return Math.floor(Math.random() * 1000000);
}

@Injectable()
export class BookService {
  @Inject()
  dbService: DbService;

  async list() {
    const books: Book[] = await this.dbService.read();
    return books;
  }

  async findById(id: number) {
    const books: Book[] = await this.dbService.read();
    return books.find((book) => book.id === id);
  }

  async create(createBookDto: CreateBookDto) {
    const books: Book[] = await this.dbService.read();

    const book = new Book();
    book.id = randomNum();
    book.author = createBookDto.author;
    book.name = createBookDto.name;
    book.description = createBookDto.description;
    book.cover = createBookDto.cover;

    books.push(book);

    await this.dbService.write(books);
    return book;
  }

  async update(updateBookDto: UpdateBookDto) {
    const books: Book[] = await this.dbService.read();

    const foundBook = books.find((book) => book.id === updateBookDto.id);

    if (!foundBook) {
      throw new BadRequestException('该图书不存在');
    }

    foundBook.author = updateBookDto.author;
    foundBook.cover = updateBookDto.cover;
    foundBook.description = updateBookDto.description;
    foundBook.name = updateBookDto.name;

    await this.dbService.write(books);
    return foundBook;
  }

  async delete(id: number) {
    const books: Book[] = await this.dbService.read();
    const index = books.findIndex((book) => book.id === id);

    if (index !== -1) {
      books.splice(index, 1);
      await this.dbService.write(books);
    }
  }
}

新增几本书籍

存入了几本书的信息

查询书籍信息

更新信息

删除

查看列表

再来个上传封面图

npm install --save multer 
npm install -save-dev @types/multer

storage.ts

import * as multer from 'multer';
import * as fs from 'fs';

const storage = multer.diskStorage({
  destination: function (req, file, cb) {
    try {
      fs.mkdirSync('uploads');
    } catch (e) {}

    cb(null, 'uploads');
  },
  filename: function (req, file, cb) {
    const uniqueSuffix =
      Date.now() +
      '-' +
      Math.round(Math.random() * 1e9) +
      '-' +
      file.originalname;
    cb(null, uniqueSuffix);
  },
});

export { storage };

controller 添加

 @Post('upload')
  @UseInterceptors(
    FileInterceptor('file', {
      dest: 'uploads',
      storage: storage,
      limits: {
        fileSize: 1024 * 1024 * 3,
      },
      fileFilter(req, file, callback) {
        const extname = path.extname(file.originalname);
        if (['.png', '.jpg', '.jpeg'].includes(extname)) {
          callback(null, true);
        } else {
          callback(new BadRequestException('只能上传图片'), false);
        }
      },
    }),
  )
  uploadFile(@UploadedFile() file: Express.Multer.File) {
    console.log('file', file);
    return file.path;
  }

上传一个别的格式会触发校验

把 uploads 目录设置为静态文件目录

这样就可以读到这个图片

上传完文件，把返回的文件路径作为 cover 字段的值传上去