server.js

var http = require('http');
var sockjs = require('sockjs');
var node_static = require('node-static');

// 1. Echo sockjs server
var sockjs_opts = {sockjs_url: "http://cdn.jsdelivr.net/sockjs/0.3.4/sockjs.min.js"};

var sockjs_echo = sockjs.createServer(sockjs_opts);
sockjs_echo.on('connection', function(conn) {
    conn.on('data', function(message) {
      console.log('message ' + message);
      conn.write(message);
    });

    setInterval(function() {
      console.log('send flip');
      conn.write("flip");
    }, 7000);

});

// 2. Static files server
var static_directory = new node_static.Server(__dirname + '/client');

// 3. Usual http stuff
var server = http.createServer();
server.addListener('request', function(req, res) {
    static_directory.serve(req, res);
});
server.addListener('upgrade', function(req,res){
    res.end();
});

sockjs_echo.installHandlers(server, {prefix:'/echo'});

var addr = 'localhost';
console.log(' [*] Listening on ' + addr + ':9999' );
server.listen(9999, addr);