How to download a file with Node.js?

You can create an HTTP GET request and pipe its response into a writable file stream:

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

var file = fs.createWriteStream("file.jpg");
var request = http.get("http://i3.ytimg.com/vi/J---aiyznGQ/mqdefault.jpg", function(response) {
  response.pipe(file);
});

If you want to support gathering information on the command line--like specifying a target file or directory, or URL--check out something like Commander.

As Brandon Tilley said, but with the appropriate control flow:

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);
    });
  });
}

Without waiting for the finish event, naive scripts may end up with an incomplete file.

Edit: Thanks to @Augusto Roman for pointing out that cb should be passed to file.close, not called explicitly.

Don't forget to handle errors! The following code is based on Augusto Roman's answer.

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.
    });
  }).on('error', function(err) { // Handle errors
    fs.unlink(dest); // Delete the file async. (But we don't check the result)
    if (cb) cb(err.message);
  });
};

gfxmonk's answer has a very tight data race between the callback and the file.close() completing. file.close() actually takes a callback that is called when the close has completed. Otherwise, immediate uses of the of the file may fail (very rarely!).

A complete solution is:

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.
    });
  });
}

Without waiting for the finish event, naive scripts may end up with an incomplete file. Without scheduling the cb callback via close, you may get a race between accessing the file and the file actually being ready.

You can use https://github.com/douzi8/ajax-request#download

request.download('http://res.m.ctrip.com/html5/Content/images/57.png', 
  function(err, res, body) {}
);

The following code is based on Brandon Tilley's answer :

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

var request = http.get("yourfile.html", function(response) {
    if (response.statusCode === 200) {
        var file = fs.createWriteStream("copy.html");
        response.pipe(file);
    }
    // Add timeout.
    request.setTimeout(12000, function () {
        request.abort();
    });
});

Don't make file when you get an error, and prefere to use timeout to close your request after X secondes.

Vince Yuan's code is great but it seems to be something wrong.

function download(url, dest, callback) {
    var file = fs.createWriteStream(dest);
    var request = http.get(url, function (response) {
        response.pipe(file);
        file.on('finish', function () {
            file.close(callback); // close() is async, call callback after close completes.
        });
        file.on('error', function (err) {
            fs.unlink(dest); // Delete the file async. (But we don't check the result)
            if (callback)
                callback(err.message);
        });
    });
}

If nothing else works, try using wget:

var exec = require('child_process').exec;

var downloadFileWGET = function(url, dest) {

    var wget = 'wget ' + url + ' -O ' + dest;

    // excute wget using child_process exec function
    var child = exec(wget, function(err, stdout, stderr) {
        if (err) throw err;
        else console.log(dest + ' downloaded to ' + dest);
    });
};