Пример работы с socket.io

var express = require("express");
var app = express();
var http = require("http").Server(app);
var io = require("socket.io")(http);
var shortid = require("shortid");
 
app.use(express.static(__dirname + "/public"));
 
io.on("connection", function (socket)
{
    var thisPlayerId = shortid.generate();
 
    console.log("client connected, id: ", thisPlayerId);
 
    socket.emit("hello", { id: thisPlayerId });
 
    socket.on("button_click", function (data)
    {
        console.log("A batton was clicked, data = " + data.mess);
    });
});
 
var port = process.env.PORT || 3000;
 
http.listen(port, function ()
{
    console.log("Listening on ", port);
});