code and solution: 2015

It was long time ago when I want to make a service where user don't need to refresh their page if there is any update. Currently I am working with a project with RapberryPi wallPad system. SO I decided to install nodeJs+Socket.io... but I need to make it work on virtual machine. So I am using Ubuntu Server but you can use Ubuntu 14

Follow the instruction:

sudo apt-get install npm
npm install -g npm
npm install socket.io
sudo npm install -g n
sudo apt-get install node
sudo npm install xml2json

Now create file in same folder:

server.js

var app = require('http').createServer(handler),

io = require('socket.io').listen(app),

parser = new require('xml2json'),

fs = require('fs');

// creating the server ( localhost:8000 )

app.listen(8000);

console.log('server listening on localhost:8000');

// on server started we can load our client.html page

function handler(req, res) {

fs.readFile(__dirname + '/client.html', function(err, data) {

if (err) {

console.log(err);

res.writeHead(500);

return res.end('Error loading client.html');

}

res.writeHead(200);

res.end(data);

});

}

// creating a new websocket to keep the content updated without any AJAX request

io.sockets.on('connection', function(socket) {

console.log(__dirname);

// watching the xml file

fs.watchFile(__dirname + '/example.xml', function(curr, prev) {

// on file change we can read the new xml

fs.readFile(__dirname + '/example.xml', function(err, data) {

if (err) throw err;

// parsing the new xml data and converting them into json file

var json = parser.toJson(data);

// send the new data to the client

socket.volatile.emit('notification', json);

});

example.xml

<?xml version="1.0" encoding="ISO-8859-1"?>
<test>
<sample>Hello world!</sample>

</test>

client.html

<html>
<head>
<title>Push notification server</title>
</head>
<body>
<time></time>
<div id="container">Try to change your xml data to update this content</div>
<script src="socket.io/socket.io.js"></script>
<script src="http://code.jquery.com/jquery-1.7.1.min.js"></script>
<script>
// creating a new websocket
var socket = io.connect('http://10.10.50.136:8000');
// on every message recived we print the new datas inside the #container div
socket.on('notification', function (data) {
// convert the json string into a valid javascript object
var _data = JSON.parse(data);

$('#container').html(_data.test.sample);
$('time').html('Last Update:' + new Date());
});
</script>
</body>

</html>

Please tell me if you get any error...

NodeJS is here with auto Client Update