node youtube-dl

grab-videos.js

var https = require('https');
var async = require('async');
var path = require('path');
var fs = require('fs');
var ytdl = require('youtube-dl');
var ytchannelids = ['UCrsECiuZUe7HObWu7UF--5A', 'valvenewsnetwork']; //channels to download, not yet used
var ytchannelid = 'UCrsECiuZUe7HObWu7UF--5A'; //channel to download, new format
var youtubeids = [];
//'valvenewsnetwork';
var apikey = 'xxxx'; //youtube api key
var jsoncontent = '';
//Grab latest video
//final url https://www.googleapis.com/youtube/v3/channels?part=contentDetails&forUsername={channelname}&key={apikey} (old)
//final url https://www.googleapis.com/youtube/v3/search?key={your_key_here}&channelId={channel_id_here}&part=snippet,id&order=date&maxResults=20
var options = {
    host : 'www.googleapis.com', //path: '/youtube/v3/channels?part=contentDetails&forUsername=' + ytchannelid + '&key=' + apikey
    path : '/youtube/v3/search?key=' + apikey + '&channelId=' + ytchannelid + '&part=snippet,id&order=date&maxResults=20',
};
//traverse object, or encode to json object and traverse this
//todo add failure, if str cannot be converted to json obj
function traverse(o, callback) {
    var type = typeof o;
	if (type == "object") {
        for (var key in o) {
            traverse(o[key], callback);
        }
    }
    else {
        JSON.parse(o, function (key, value) {
            if (key !== '') {
                callback.call(this, key, value);
            }
            return value;
        }
        );
    }
}
callback = function (response) {
    var str = '';
	//build json string from body
    response.on('data', function (chunk) {
        str += chunk;
    }
    );
    response.on('end', function () {
		//traverse from json string and build my array of youtube video ids
        traverse(str, function (key, value) {
            switch (key) {
                case 'videoId':
                    youtubeids.push(value);
                    //console.log(youtubeids);
                    break;
                    default  : break;
            }
        }
        );
        //console.log(youtubeids);
		//finally have my array of youtube ids, now give it to the download func
		DLVideos(youtubeids);
    }
    );
}
//make the call to youtube api to get the videos
https.get(options, callback);
function DLVideos(youtubeids) {
    async.each(youtubeids, function (singleVideoId, nextItem) {
		
		
		var downloaded = 0;
		//build output file name {video_id}.mp4 - will later be renamed to {video_title}.mp4
		var output = singleVideoId + '.mp4';
		var size = 0;
		if (fs.existsSync(output)) { downloaded = fs.statSync(output).size; }
		//console.log(downloaded);

		var video = ytdl('https://www.youtube.com/watch?v=' + singleVideoId,

		  // Optional arguments passed to youtube-dl.
		  ['--format=best'],

		  // start will be sent as a range header
		  {start: downloaded, cwd: __dirname});

		// Will be called when the download starts.
		video.on('info', function(info) {

		  'use strict';
		  //console.log('Download started');
		  //console.log('filename: ' + info._filename);

		  // info.size will be the amount to download, add
		  var total = info.size + downloaded;
		  //console.log('size: ' + total);
		  size = info.size;

		  if (downloaded > 0) {
			// size will be the amount already downloaded
			console.log('resuming from: ' + downloaded);

			// display the remaining bytes to download
			console.log('remaining bytes: ' + info.size);
		  }
		});

		video.pipe(fs.createWriteStream(output, {flags: 'a'}));

		// Will be called if download was already completed and there is nothing more to download.
		video.on('complete', function complete(info) {
		  'use strict';
		  //console.log('filename: ' + info._filename + ' already downloaded.');
		  
		  console.log("\nRenaming");
		  console.log(output);
		  console.log("to");
		  console.log(info._filename);
		  console.log("\n");
		  fs.renameSync(output, info._filename)
		  
		  //callback to let async know we're ready for the next item
		  nextItem();
		});

		video.on('end', function end() {
		  'use strict';
		  console.log('finished downloading!');
		});
		
		var pos = 0;
		video.on('data', function data(chunk) {
            'use strict';
            pos += chunk.length;
            // `size` should not be 0 here.
            if (size) {
                var percent = (pos / size * 100).toFixed(2);
                process.stdout.cursorTo(0);
                process.stdout.clearLine(1);
                process.stdout.write(percent + '%');
            }
        }
        );
    }
    , function (err) {
        // downloaded all
    }
    );
}