Koa2上传下载.ts如何实现针对长尾关键词的优化？

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在koa2中，以下是如何上传和下载文件的简化示例：

javascriptimport * as fs from 'fs';import * as multer from 'koa-multer';import * as Router from 'koa-router';

const uploader=multer({ dest: 'uploads/' });const router=new Router();

router.post('/upload', uploader.single('file'), async (ctx)=> { const file=ctx.req.file; if (file) { ctx.body={ message: '文件上传成功', fileName: file.filename }; } else { ctx.body={ message: '文件上传失败' }; }});

router.get('/download/:filename', async (ctx)=> { const { filename }=ctx.params; const file=`./uploads/${filename}`; const stat=fs.statSync(file); const range=ctx.headers.range; const contentLength=stat.size; const start=parseInt(range && range.replace(/bytes=/, ), 10); const end=Math.min(start + 10 ** 6, contentLength - 1);

ctx.setHeader('Content-Range', `bytes ${start}-${end}/${contentLength}`); ctx.setHeader('Content-Length', end - start + 1); ctx.setHeader('Content-Type', 'application/octet-stream');

const stream=fs.createReadStream(file, { start, end }); stream.pipe(ctx.res);});

koa2上传下载.ts

import * as fs from 'fs' import * as multer from 'koa-multer' import * as Router from 'koa-router' // import * as lowdb from 'lowdb' const uploader = multer({ dest: 'uploads/' }) const router = new Router() router.get('/attachments/:id', async (ctx) => { const { id } = ctx.params const info = ctx.db.get('attachments').find({ id }).value() ctx.set('Content-Disposition', `attachment; filename=${info.originalname}`) ctx.set('Content-Type', info.mimetype) ctx.set('Content-Length', info.size) ctx.body = fs.createReadStream(`uploads/${id}`) }) router.post('/upload', uploader.single('file'), async (ctx) => { const info = Object.assign({}, ctx.req.file, { id: ctx.req.file.filename }) await ctx.db.get('attachments').push(info).write() ctx.body = {ok: true, attachment: info} })