Simple node js http server for reference

var http = require("http"),
url = require("url"),
path = require("path"),
fs = require("fs")
port = process.argv[2] || 8888;

http.createServer(function(request, response) {

var uri = url.parse(request.url).pathname
, filename = path.join(process.cwd(), uri);

var contentTypesByExtension = {
'.html': "text/html",
'.css':  "text/css",
'.js':   "text/javascript"
};

path.exists(filename, function(exists) {
if(!exists) {
  response.writeHead(404, {"Content-Type": "text/plain"});
  response.write("404 Not Found\n");
  response.end();
  return;
}

if (fs.statSync(filename).isDirectory()) filename += '/index.html';

fs.readFile(filename, "binary", function(err, file) {
  if(err) {      
    response.writeHead(500, {"Content-Type": "text/plain"});
    response.write(err + "\n");
    response.end();
    return;
  }

  var headers = {};
  var contentType = contentTypesByExtension[path.extname(filename)];
  if (contentType) headers["Content-Type"] = contentType;
  response.writeHead(200, headers);
  response.write(file, "binary");
  response.end();
});
});
}).listen(parseInt(port, 10));

console.log("Static file server running at\n  => http://localhost:" + port + "/\nCTRL + C to shutdown");