什么是在NodeJS下载大文件的方法？

下面的服务器代码使用wget http://localhost:11146/base/bigFile.zip工作正常，但不使用客户端代码。

服务器端代码。

 var http = require("http"); var fs = require("fs"); var filename = "base/bigFile.zip"; var serv = http.createServer(function (req, res) { var stat = fs.statSync(filename); res.writeHeader(200, {"Content-Length": stat.size}); var fReadStream = fs.createReadStream(filename); fReadStream.on('data', function (chunk) { if(!res.write(chunk)){ fReadStream.pause(); } }); fReadStream.on('end', function () { res.end(); }); res.on("drain", function () { fReadStream.resume(); }); }); serv.listen(1114); 

客户端代码使用请求模块。 这个代码有什么错？

 var request = require('request') request('http:/localhost:11146/base/bigFile.zip', function (error, response, body) { console.log('error:', error); // Print the error if one occurred console.log('statusCode:', response && response.statusCode); // Print the response status code if a response was received console.log('body:', body); // Print the HTML for the Google homepage. }); 

以上客户端代码错误在下面 –

 error: Error: Invalid protocol at Request.init (/Users/air/Projects/node_modules/request/request.js:338:51) at new Request (/Users/air/Projects//node_modules/request/request.js:105:8) at request (/Users/air/Projects/Vertico/Vertico-CLI/node_modules/request/index.js:53:11) at Object.<anonymous> (/Users/air/Projects/req.js:2:1) at Module._compile (module.js:569:30) at Object.Module._extensions..js (module.js:580:10) at Module.load (module.js:503:32) at tryModuleLoad (module.js:466:12) at Function.Module._load (module.js:458:3) at Function.Module.runMain (module.js:605:10) statusCode: undefined body: undefined 

我修改客户端使用wget shell进程而不是请求包，代码如下，问题是 – 我无法看到很好的下载进度的wget，任何解决这个代码，这样我可以看到进度栏在孩子的过程中。

 const fs = require('fs'); const child_process = require('child_process'); var workerProcess = child_process.spawn('wget', ['-O','fdsf.zip', 'http://localhost:11146/base/bigFile.zip']); workerProcess.stdout.on('data', function (data) { console.log('stdout: ' + data); }); workerProcess.stderr.on('data', function (data) { //console.log('stderr: ' + data); }); workerProcess.on('close', function (code) { console.log('Download Completed' + code); }); 

所以最后我想知道如何使用nodejs编写的客户端代码下载文件？

Answer 1

最简单的方法是使用request模块

这里你试图把整个结果存储在内存和控制台中。 5GB非常大，要么增加Node.js内存限制（不推荐），要么必须使用stream。 请参阅下面的request npm文档中的stream式示例 ：

 const fs = require('fs'); const request = require('request'); request('http://google.com/doodle.png').pipe(fs.createWriteStream('doodle.png')) 

您必须输出响应，以便无论是1MB还是1GB或1TB，只有一小部分文件将在内存中，并且会尽快写入磁盘。 你可以使用相同的方法使用Node.js内置的函数，但是实现将很困难，就像request模块在那里重新发明轮子一样。

对于进度下载，您可以使用request-progress模块和request模块，请参阅下面的示例（ 摘自其文档 ）：

 var fs = require('fs'); var request = require('request'); var progress = require('request-progress'); // The options argument is optional so you can omit it progress(request('https://az412801.vo.msecnd.net/vhd/VMBuild_20141027/VirtualBox/IE11/Windows/IE11.Win8.1.For.Windows.VirtualBox.zip'), { // throttle: 2000, // Throttle the progress event to 2000ms, defaults to 1000ms // delay: 1000, // Only start to emit after 1000ms delay, defaults to 0ms // lengthHeader: 'x-transfer-length' // Length header to use, defaults to content-length }) .on('progress', function (state) { // The state is an object that looks like this: // { // percent: 0.5, // Overall percent (between 0 to 1) // speed: 554732, // The download speed in bytes/sec // size: { // total: 90044871, // The total payload size in bytes // transferred: 27610959 // The transferred payload size in bytes // }, // time: { // elapsed: 36.235, // The total elapsed seconds since the start (3 decimals) // remaining: 81.403 // The remaining seconds to finish (3 decimals) // } // } console.log('progress', state); }) .on('error', function (err) { // Do something with err }) .on('end', function () { // Do something after request finishes }) .pipe(fs.createWriteStream('IE11.Win8.1.For.Windows.VirtualBox.zip')); 

Answer 2

 var request = require('request') request('http:/localhost:11146/base/bigFile.zip', function (error, response, body) { console.log('error:', error); // Print the error if one occurred console.log('statusCode:', response && response.statusCode); // Print the response status code if a response was received console.log('body:', body); // Print the HTML for the Google homepage. }); 

它应该是http://localhost:11146/base/bigFile.zip而不是http:/localhost:11146/base/bigFile.zip

Answer 3

我的版本的代码。

 var fs = require('fs'); var request = require('request'); var progress = require('request-progress'); var url = 'http://localhost:4181'; var filename = 's.zip'; var pre = '----'; downloadManager = function(url,filename){ progress(request(url), { throttle:500 }) .on('progress', function (state) { process.stdout.write(pre+''+ (Math.round(state.percent*100))+"%"); }) .on('error', function (err) { console.log('error :( '+err); }) .on('end', function () { console.log(pre+'100% \n Download Completed'); }) .pipe(fs.createWriteStream(filename)); }; downloadManager(url,filename);