Postnauka video downloader

index.js

const INCOMPLETE_DOWNLOADS_FOLDER_PATH = '/Users/vz/Downloads/';
const COMPLETE_DOWNLOADS_FOLDER_PATH = '/Users/vz/Music/iTunes/iTunes Media/Automatically Add to iTunes/';

const USER_AGENT = 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_2) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.52 Safari/537.11';
const VIDEO_INFO_URL = 'http://player.vimeo.com/config/';
const VIDEO_DOWNLOAD_URL = 'http://player.vimeo.com/play_redirect?clip_id={{id}}&sig={{signature}}&time={{timestamp}}&quality={{quality}}&codecs=H264&type=moogaloop&embed_location={{location}}';

const RECHECK_PERIOD = 2 * 60 * 60 * 1000;

var fs = require("fs"),
	xml2js = require('xml2js'),
	request = require('request'),
	db = new require('dirty')('data.db.json'),
	ProgressBar = require('progress'),
	growl = require('growl'),

	videos = {};

function stripHTML(s) {
	return s.replace(/<[^>]+>/gm, ' ');
}

function createVideo(rawVideoData) {
	return {
		title: rawVideoData.title[0],
		description: stripHTML(rawVideoData.description[0]),
		pageUrl: rawVideoData.link[0],
		date: +new Date(rawVideoData.pubDate[0]),
		category: rawVideoData.category
	};
}

function getVimeoId(url, callback) {
	request(url, function(error, response, body) {
		if (!error && response.statusCode == 200) {
			var match = body.match(/https?:\/\/player\.vimeo\.com\/video\/(\d+)/i);
			callback(match && match[1] || null);
		} else {
			callback(null);
		}
	});
}

function getDownloadUrl(id, location, callback) {
	request({
		url: VIDEO_INFO_URL + id,
		headers: {
			'User-Agent': USER_AGENT,
			'Referer': location
		}
	}, function(error, response, body) {
		if (!error && response.statusCode == 200) {
			try {
				var data = JSON.parse(body);
				var url = VIDEO_DOWNLOAD_URL
							.replace('{{id}}', data.video.id)
							.replace('{{signature}}', data.request.signature)
							.replace('{{timestamp}}', data.request.timestamp)
							.replace('{{quality}}', data.video.files.h264[0]) // best format always goes first
							.replace('{{location}}', location);
				callback(url);
			} catch(e) {
				callback(null);
			}
		} else {
			callback(null)
		}
	});
}

function downloadVideo(videoUrl, name, callback) {
	var req = request({
		url: videoUrl,
		headers: {
			'User-Agent': USER_AGENT
		}
	});

	req.on('response', function(res) {
		var file = fs.createWriteStream(INCOMPLETE_DOWNLOADS_FOLDER_PATH + name),
			len = parseInt(res.headers['content-length'], 10),
			bar = new ProgressBar('[:bar] :percent :etas', {
				complete: '=',
				incomplete: ' ',
				width: 40,
				total: len
			});

		res.on('data', function(chunk){
			bar.tick(chunk.length);
			file.write(chunk, encoding='binary');
		});

		res.on('end', function(){
			console.log('\n');
			file.end();
			fs.rename(INCOMPLETE_DOWNLOADS_FOLDER_PATH + name, COMPLETE_DOWNLOADS_FOLDER_PATH + name);
			growl(name + ' has been successfully downloaded.', {title: 'Postnauka'});
			callback(true);
		});

		res.on('error', function() {
			console.log('\n');
			file.end();
			growl(name + ' has failed to download.', {title: 'Postnauka'});
			callback(null);
		});

	});

	req.end();
}

function downloadVideos(items, callback) {
	var queue = [];
	for(var url in items) {
		if (!items[url].done) {
			queue.push(items[url]);
		}
	}
	queue.sort(function(a, b) {
		return a.date - b.date;
	});
	processQueue(queue, callback);
}

function processQueue(items, callback) {
	var item = items.shift();

	if (!item) {
		return callback();
	}

	console.log(item.title);
	console.log('* geting vimeo id...');
	getVimeoId(item.pageUrl, function(id) {
		if (id === null) {
			console.log('! could not get vimeo id, file skipped.');
			return processQueue(items, callback);
		}
		console.log('* geting download url...');
		getDownloadUrl(id, item.pageUrl, function(url) {
			if (url === null) {
				console.log('! could not get download url, file skipped.');
				return processQueue(items, callback);
			}
			downloadVideo(url, item.title + '.mp4', function(result) {
				if (result) {
					item.done = true;
					db.set('rss_items', videos);
					processQueue(items, callback);
				} else {
					console.log('! download failed.');
				}
			})
		});
	});
}

function checkForNewVideos() {
	request('http://postnauka.ru/video/feed', function (error, response, body) {
		if (!error && response.statusCode == 200) {
			var parser = new xml2js.Parser;
			parser.parseString(body, function (err, result) {
				var c = 0;
				result.rss.channel[0].item.forEach(function(item) {
					var pageUrl = item.link[0];
					if (!videos[pageUrl]) {
						c++;
						videos[pageUrl] = createVideo(item);
					}
				});
				if (c) {
					var msg = c + ' new video' + (c * 1 ? 's' : '') + ' found.';
					growl(msg, {title: 'Postnauka'});
					console.log(msg + ' found.');
				}

				downloadVideos(videos, function() {
					setTimeout(checkForNewVideos, RECHECK_PERIOD);
				});
			});
		}
	});
}

db.on('load', function() {
	videos = db.get('rss_items') || {};
	checkForNewVideos();
});