Node.js (v0.4) sendfile() non-caching fileserver - fast and efficient!

filesender.js

var http = require('http');
var fs = require('fs');
var path = require('path');
var constants = require('constants');
var timers = require('timers');
var port = 8080;

http.createServer(function(req, res) {
	if(req.url == '/') {
		res.writeHead(200, { 'Content-Type': 'text/plain' });
		res.end('filesender.js v1\n');
	}
	else {
		var fn = path.resolve('.'+ req.url.replace(/\.\./g, '.'));
		
		fs.open(fn, 'r', function(err, fd) {
			if(err) {
				var msg = 'Not found: ' + fn;
				res.writeHead(404, {
					'Content-Length': msg.length,
					'Content-Type': 'text/plain'
				});
				res.end(msg);
			}
			else {
				var off = 0;
				var s = res.socket;
				var size = fs.fstatSync(fd).size;
				
				console.log('serving file', fn, 'of size', size);

				s.write('HTTP/1.1 200 OK\r\n' +
					'Content-Length: ' + size + '\r\n' +
					'Content-Type: application/octet-stream\r\n' +
					'Cache-Control: no-cache\r\n' +
					'Connection: close\r\n' +
					'Pragma: no-cache\r\n' +
					'Expires: -1\r\n' +
					'\r\n'
				);
				
				var sendData = function() {
					s.removeListener('drain', sendData);
					try {
						do {
							off += fs.sendfileSync(s.fd, fd, off, size - off);
							timers.active(s);
						}
						while(off < size);
						s.flush();
					}
					catch(e) {
						if(e.errno === constants.EAGAIN) {
							s.on('drain', sendData);
							s._writeWatcher.start();
						}
						else {
							console.log(e);
							s.end();
						}
					}
				};
				sendData();
			}
		});
	}
}).listen(port, "0.0.0.0");

console.log('serving files from directory',
	path.resolve('.'), 'at port', port);