Node.js socket.io create server

var app = require('http').createServer(handler)
  , io = require('socket.io').listen(app)
  , port = process.env.PORT || 80;/* w  w w.  j a  v  a 2  s .c om*/

app.listen(port);
console.log("Listening on port "+port);

function handler (req, res) {
  console.log("The url of the request is "+req.url);
}

io.sockets.on('connection', function (socket) {
  console.log("This is app-server, and I'm connected to someone.");
});