Downloads mp3 files from URLs listed in files.txt

download.js

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

var urls = fs.readFileSync('files.txt', {encoding: 'utf8'}).split('\n');

next();

function next() {
	if (urls.length > 0) {
		download(urls.pop(), next);
	} else {
		console.log('Done');
	}
}

function download(url, callback) {
	http.get(url, function(res) {
		console.log('Requesting: ' + url);
		if (302 == res.statusCode) {
			var redirectUrl = res.headers.location;
			console.log('Redirecting to ' + redirectUrl);
			download(redirectUrl, callback);
		} else if (200 == res.statusCode) {
			var filename = getFilename(url);
			if (!filename) {
				console.log('Unable to parse filename. Skipped.');
				return;
			}			
			var out = fs.createWriteStream(filename);
			res.pipe(out);

			var length = Number(res.headers['content-length']);
			var received = 0;
			res.on('data', function(chunk) {
				received += chunk.length;
				printProgress((received * 100 / length).toFixed(2));
			});
			out.on('finish', function() {
				console.log('\nSaved to: ' + filename);
				if (callback) {
					callback();
				}
			});
		}
	}).on('error', function(e) {
		console.log('Failed to download ' + url + ' :' + e);
		if (callback) {
			callback();
		}
	});
}

function getFilename(url) {
	var re = /\/([A-Za-z0-9_\-\.]*.mp3)/;
	if (re.test(url)) {
		return re.exec(url)[1];
	}
}

function printProgress(progress) {	
	var width = process.stdout.columns - 30;
	var done = progress * width / 100;
	process.stdout.write('[ ' + progress + '% ][');
	for (var i = 0; i < done; i++) {
		process.stdout.write('=');
	}
	for (var i = 0; i < width - done; i++) {
		process.stdout.write('.');
	}
	process.stdout.write(']\r');
}