Node.js 实现存储服务的下载功能【包含前后端代码】

function download(href, title) {    const a = document.createElement('a');    a.setAttribute('href', href);    a.setAttribute('download', title);    a.click();}

var express = require('express');var fs=require("fs");var app = express();
app.get("/api/download", download.single('file'), Admincontroller.getdownload);
// 下载函数一exports.getdownload = function (req, res) {  var id = req.query.id;  if (id == "") {    res.json({ success: 0, "error": "参数错误" });    return;  }  // 根据 id 拼接文件名  var des = "./public/resource/";  var fileName = des + id + ".mp4";  var exist = fs.existsSync(fileName);  if (exist) {    res.download(fileName);  } else {    res.json({ success: 1, "error": "目标文件不存在" });  }
} 

// 下载函数exports.getdownload = function (req, res) {    var id = req.query.id;    if (id == "") {        res.json({ success: 0, "error": "参数错误" });        return;    }    // 根据 id 拼接文件名    var des = "./public/resource/";    var fileName = des + id + ".mp4";    //增加中文处理    var filenameex = filename + ".mp4"    var realName = encodeURI(filenameex,"GBK")    realName = realName.toString('iso8859-1')    res.setHeader('content-Type','application/octet-stream');    res.setHeader('content-Disposition', `attachment;filename=` + realName);    var exist = fs.existsSync(fileurl);    if (exist) {        fs.createReadStream(fileurl).pipe(res);    } else {        res.json({            success: 0,            code: 1,            "error":"目标文件不存在",        });    }