How can I set cookie in node js using express framework?

In my application, I need to set a cookie using the express framework. I have tried the following code but it’s not setting the cookie.

var express = require('express'), http = require('http');
var app = express();
app.configure(function(){
      app.use(express.cookieParser());
      app.use(express.static(__dirname + '/public'));

      app.use(function (req, res) {
           var randomNumber=Math.random().toString();
           randomNumber=randomNumber.substring(2,randomNumber.length);
           res.cookie('cokkieName',randomNumber, { maxAge: 900000, httpOnly: true })

           console.log('cookie have created successfully');
      });

});

var server = http.createServer(app);
var io = require('socket.io').listen(server);
server.listen(5555);