NestJS学习笔记之下载图片

下载文件的方式有好多种

1.download 直接下载

这个文件信息应该存数据库 ，这里演示就写死了

import { Controller, Get, Post, Body, Patch, Param, Delete, UploadedFile, UseInterceptors, Res } from '@nestjs/common';
import { UploadService } from './upload.service';
import { CreateUploadDto } from './dto/create-upload.dto';
import { UpdateUploadDto } from './dto/update-upload.dto';
import { FileInterceptor } from '@nestjs/platform-express';
import { join } from 'path';
import { Response } from 'express';

@Controller('upload')
export class UploadController {
  constructor(private readonly uploadService: UploadService) { }

  @Post('album')
  @UseInterceptors(FileInterceptor('file'))
  create(@UploadedFile() file) {
    console.log(file);
    return true;
  }

  @Get('export')
  downLoad(@Res() res: Response) {
    const url = join(__dirname, '../images/1708440096666.jpg');
    res.download(url)
  }

}

浏览器访问接口http://localhost:3000/upload/export，可以看到图片已经被下载到本地了

2.使用文件流的方式下载

可以使用compressing把他压缩成一个zip包

import {zip} from 'compressing'

  @Get('stream')
  async down (@Res() res:Response) {
    const url = join(__dirname,'../images/1662894316133.png')
    const tarStream  = new zip.Stream()
    await tarStream.addEntry(url)
    
    res.setHeader('Content-Type', 'application/octet-stream');
   
    res.setHeader(
      'Content-Disposition',  
      `attachment; filename=xiaoman`,
    );
 
    tarStream.pipe(res)
 
  }

前端接受流

const useFetch = async (url: string) => {
  const res = await fetch(url).then(res => res.arrayBuffer())
  console.log(res)
  const a = document.createElement('a')
  a.href = URL.createObjectURL(new Blob([res],{
    // type:"image/png"
  }))
  a.download = 'zl.zip'
  a.click()
}
 
const download = () => {
  useFetch('http://localhost:3000/upload/stream')
}