node webSocket backend example

echo_server.js

var sys = require('sys'),
    http = require('http'),  
    io = require('socket.io'), // for npm, otherwise use require('./path/to/socket.io') 
    fs = require('fs');

var pageContent = ''; // content of the client page

// create web server and reply the client page on http request
var server = http.createServer(function(req, res){ 
    res.writeHead(200, {'Content-Type': 'text/html'}); 
    res.end(pageContent); 
});

// load client page content
fs.readFile('echo.html', function(err, content) {
    if (err) throw err;
    pageContent = content;
    start();
});    

// start web server
function start() {
    server.listen(8000);
}

// connected clients
var clients = [];

// socket.io 
var socket = io.listen(server); 
socket.on('connection', function(client){
    clients.push(client);
    client.on('message', function(data) {
        // broadcast the message to all clients
        //   this loop is the same as
        //   socket.broadcast(data);
        for (var i in clients) {
            clients[i].send(data);
        }
    });
    client.on('disconnect', function() {
        // remove client from the list
        var index = clients.indexOf(client);
        if (index != -1)
            clients.splice(index, 1);
    }); 
});