Download Youtube-Video in node.js

youtube.js

var http = require('http')
var fs = require('fs')
var argv = require('optimist').argv

var rxVideoID = /v=([\]\[!"#$%'()*+,.\/:;<=>?@\^_`{|}~-\w]*)/
var link = argv._.toString()
var videoID = link.match(rxVideoID)[1]

http.get("http://www.youtube.com/get_video_info?video_id="+videoID, function(res) {
  var chunks = []
  res.on('data', function(chunk){chunks.push(chunk)
  }).on('end', function(){
    var data = Buffer.concat(chunks).toString()
    var videoInfo = parseVideoInfo(data)
    downloadVideo(videoInfo)
  })
}).on('error', function(e) {
  console.log("Got error: " + e.message)
});

function parseVideoInfo(videoInfo) {
    var rxUrlMap = /url_encoded_fmt_stream_map=([\]\[!"#$%'()*+,.\/:;<=>?@\^_`{|}~-\w]*)/
    urlmap = unescape(videoInfo.match(rxUrlMap)[1])
    
    var rxUrlG = /url=([\]\[!"#$%'()*+,.\/:;<=>?@\^_`{|}~-\w]*)/g
    var rxUrl  = /url=([\]\[!"#$%'()*+,.\/:;<=>?@\^_`{|}~-\w]*)/
    var urls = urlmap.match(rxUrlG)
    urls = map(urls, function(s) {return s.match(rxUrl)[1]} )
    urls = map(urls, unescape)
    
    var rxTitle  = /title=([\]\[!"#$%'()*+,.\/:;<=>?@\^_`{|}~-\w]*)/
    var title = argv.o ? argv.o : videoInfo.match(rxTitle)[1]
    
    return { title: title, urls: urls }
}

function downloadVideo(videoInfo) {
    var url = videoInfo.urls[0];
    var filename = videoInfo.title + ".flv"
    
    http.get(url,
      function(res) {
        var stream = fs.createWriteStream(filename)
        res.pipe(stream)
      })
      
    console.log("Downloading to "+filename);
}



function map (a,f) {
    for(i=0;i<a.length;i++){
        a[i]= f(a[i])
    }
    return a
}

hi guy !

Great job ! I would like to know where did you found the "http://www.youtube.com/get_video_info?video_id=" link ?

Thanks again !

@lucasmrdt
You can find links like that in the youtube api documentation

youtube-dl has some overhead but i cant get this to work consistently without it.
Please if someone has code for node to grab the stream URL please help out, the problem is mostly the fact that some youtube videos require you to update a signature as well which is another request and the documentation on this is scarce. You can try to dig through source code of downloaders but I'm having a hard time figuring it out.

const ytdl = require('youtube-dl');

var link = req.body.YTURL;

ytdl.exec(link, ['-f best', '-s', '-g'], {}, function(err, output) {
    if (err) throw err;
    res.json(output[0]);
});

i want school management system.
teachers have to login and download video from youtube capturing url link.
student learn via video.
could you help me?