Gfxmonk的答案在回调和file.close()完成之间有一个非常紧张的数据竞赛。File.close()实际上接受一个回调函数，该函数在close完成时被调用。否则，立即使用文件可能会失败(非常罕见!)。

一个完整的解决方案是:

var http = require('http');
var fs = require('fs');

var download = function(url, dest, cb) {
  var file = fs.createWriteStream(dest);
  var request = http.get(url, function(response) {
    response.pipe(file);
    file.on('finish', function() {
      file.close(cb);  // close() is async, call cb after close completes.
    });
  });
}

如果不等待finish事件，幼稚的脚本可能最终得到一个不完整的文件。如果不通过close调度cb回调，您可能会在访问文件和文件实际准备就绪之间出现竞争。

如果您正在使用express，请使用res.download()方法。否则使用fs模块。

app.get('/read-android', function(req, res) {
   var file = "/home/sony/Documents/docs/Android.apk";
    res.download(file) 
}); 

(or)

   function readApp(req,res) {
      var file = req.fileName,
          filePath = "/home/sony/Documents/docs/";
      fs.exists(filePath, function(exists){
          if (exists) {     
            res.writeHead(200, {
              "Content-Type": "application/octet-stream",
              "Content-Disposition" : "attachment; filename=" + file});
            fs.createReadStream(filePath + file).pipe(res);
          } else {
            res.writeHead(400, {"Content-Type": "text/plain"});
            res.end("ERROR File does NOT Exists.ipa");
          }
        });  
    }

说到处理错误，监听请求错误甚至更好。我甚至会通过检查响应代码来验证。这里认为只有200个响应代码成功，但其他代码可能很好。

const fs = require('fs');
const http = require('http');

const download = (url, dest, cb) => {
    const file = fs.createWriteStream(dest);

    const request = http.get(url, (response) => {
        // check if response is success
        if (response.statusCode !== 200) {
            return cb('Response status was ' + response.statusCode);
        }

        response.pipe(file);
    });

    // close() is async, call cb after close completes
    file.on('finish', () => file.close(cb));

    // check for request error too
    request.on('error', (err) => {
        fs.unlink(dest, () => cb(err.message)); // delete the (partial) file and then return the error
    });

    file.on('error', (err) => { // Handle errors
        fs.unlink(dest, () => cb(err.message)); // delete the (partial) file and then return the error
    });
};

尽管这段代码相对简单，但我建议使用request模块，因为它处理更多http不支持的协议(你好，HTTPS!)。

可以这样做:

const fs = require('fs');
const request = require('request');

const download = (url, dest, cb) => {
    const file = fs.createWriteStream(dest);
    const sendReq = request.get(url);
    
    // verify response code
    sendReq.on('response', (response) => {
        if (response.statusCode !== 200) {
            return cb('Response status was ' + response.statusCode);
        }

        sendReq.pipe(file);
    });

    // close() is async, call cb after close completes
    file.on('finish', () => file.close(cb));

    // check for request errors
    sendReq.on('error', (err) => {
        fs.unlink(dest, () => cb(err.message)); // delete the (partial) file and then return the error
    });

    file.on('error', (err) => { // Handle errors
        fs.unlink(dest, () => cb(err.message)); // delete the (partial) file and then return the error
    });
};

编辑:

要使它与https兼容，请更改

const http = require('http');

to

const http = require('https');

您可以尝试使用res.redirect到https文件下载url，然后它将下载文件。

如:res.redirect(“https / / static.file.com/file.txt”);

我更喜欢request()，因为你可以同时使用http和https。

request('http://i3.ytimg.com/vi/J---aiyznGQ/mqdefault.jpg')
  .pipe(fs.createWriteStream('cat.jpg'))

2022年底编辑:

Node v18及以上版本自带自带的Fetch API支持。使用它。

最初的回答:

对于支持承诺的节点，与其他答案相比，一个简单的(部分)Fetch API的Node shim只需要少量额外的代码:

const fs = require(`fs`);
const http = require(`http`);
const https = require(`https`);

module.exports = function fetch(url) {
  return new Promise((resolve, reject) => {
    const data = [];
    const client = url.startsWith("https") ? https : http;
    client
      .request(url, (res) => {
        res.on(`data`, (chunk) => data.push(chunk));
        res.on(`end`, () => {
          const asBytes = Buffer.concat(data);
          const asString = asBytes.toString(`utf8`);
          resolve({
            arrayBuffer: async () => asBytes,
            json: async () => JSON.parse(asString),
            text: async () => asString,
          });
        });
        res.on(`error`, (e) => reject(e));
      })
      .end();
  });
};

你可以用它来做任何你需要的事情，使用普通的fetch语法:

const fetch = require(`./tiny-fetch.js`);

fetch(`https://placekitten.com/200/300`)
  .then(res => res.arrayBuffer())
  .then(bytes => fs.writeFileSync(`kitten.jpg`, bytes))
  .catch(e => console.error(e));

fetch(`https://jsonplaceholder.typicode.com/todos/1`)
  .then(res => res.json())
  .then(obj => console.log(obj))
  .catch(e => console.error(e));

// etc.