August | 2014 | YS Tech Share

Has been playing around on socket.io but couldn’t get the client and server code separated. I need the server code running on a pc while the client code is just a static html that I can embed inside phonegap or etc. After hours of struggle, I decided to looks for other library and finally rest on these 2 combination: https://github.com/Worlize/WebSocket-Node & https://code.google.com/p/jquery-websocket/ thru Simon’s Hamsphire’s kraken blog Simon wrote a very good article on demonstrating these 2 combination. My article here further demonstrate how to broadcast the msg to multiple clients and fixed some bugs. Ok, so lets’ do this step by step, server first then only the client.

Server part:

var WebSocketServer = require('websocket').server;
var http = require('http');
 
var server = http.createServer(function(request, response) {
    console.log((new Date()) + ' Received request for ' + request.url);
    response.writeHead(404);
    response.end();
});
server.listen(8080, function() {
    console.log((new Date()) + ' Server is listening on port 8080');
});
 
wsServer = new WebSocketServer({
    httpServer: server,
    // You should not use autoAcceptConnections for production
    // applications, as it defeats all standard cross-origin protection
    // facilities built into the protocol and the browser.  You should
    // *always* verify the connection's origin and decide whether or not
    // to accept it.
    autoAcceptConnections: false
});
 
function originIsAllowed(origin) {
  // put logic here to detect whether the specified origin is allowed.
  return true;
}

var connections = {};
var connectionIDCounter = 0;
	
wsServer.on('request', function(request) {
    if (!originIsAllowed(request.origin)) {
      // Make sure we only accept requests from an allowed origin
      request.reject();
      console.log((new Date()) + ' Connection from origin ' + request.origin + ' rejected.');
      return;
    }
 
    //var connection = request.accept('kraken-protocol', request.origin);
    var connection = request.accept(null, request.origin);
	connection.id = connectionIDCounter ++;
    connections[connection.id] = connection;
	
   console.log((new Date()) + ' Connection ID ' + connection.id + ' accepted.');
	
    connection.on('message', function(message) {
        if (message.type === 'utf8') {
            console.log('Received Message: ' + message.utf8Data);
            //connection.sendUTF(message.utf8Data);
			broadcast(message.utf8Data)
        }
        else if (message.type === 'binary') {
            console.log('Received Binary Message of ' + message.binaryData.length + ' bytes');
            connection.sendBytes(message.binaryData);
        }
		
    });
	
    connection.on('close', function(reasonCode, description) {
        console.log((new Date()) + ' Peer ' + connection.remoteAddress + ' disconnected. '+"Connection ID: " + connection.id);
		// Make sure to remove closed connections from the global pool
        delete connections[connection.id];
    });
});

// Broadcast to all open connections
function broadcast(data) {
    Object.keys(connections).forEach(function(key) {
        var connection = connections[key];
        if (connection.connected) {
            connection.send(data);
        }
    });
}

// Send a message to a connection by its connectionID
function sendToConnectionId(connectionID, data) {
    var connection = connections[connectionID];
    if (connection && connection.connected) {
        connection.send(data);
    }
}

var WebSocketServer = require('websocket').server;

var http = require('http');

var server = http.createServer(function(request, response) {

console.log((new Date()) + ' Received request for ' + request.url);

response.writeHead(404);

response.end();

});

server.listen(8080, function() {

console.log((new Date()) + ' Server is listening on port 8080');

});

wsServer = new WebSocketServer({

httpServer: server,

// You should not use autoAcceptConnections for production

// applications, as it defeats all standard cross-origin protection

// facilities built into the protocol and the browser. You should

// *always* verify the connection's origin and decide whether or not

// to accept it.

autoAcceptConnections: false

});

function originIsAllowed(origin) {

// put logic here to detect whether the specified origin is allowed.

return true;

}

var connections = {};

var connectionIDCounter = 0;

wsServer.on('request', function(request) {

if (!originIsAllowed(request.origin)) {

// Make sure we only accept requests from an allowed origin

request.reject();

console.log((new Date()) + ' Connection from origin ' + request.origin + ' rejected.');

return;

}

//var connection = request.accept('kraken-protocol', request.origin);

var connection = request.accept(null, request.origin);

connection.id = connectionIDCounter ++;

connections[connection.id] = connection;

console.log((new Date()) + ' Connection ID ' + connection.id + ' accepted.');

connection.on('message', function(message) {

if (message.type === 'utf8') {

console.log('Received Message: ' + message.utf8Data);

//connection.sendUTF(message.utf8Data);

broadcast(message.utf8Data)

}

else if (message.type === 'binary') {

console.log('Received Binary Message of ' + message.binaryData.length + ' bytes');

connection.sendBytes(message.binaryData);

}

});

connection.on('close', function(reasonCode, description) {

console.log((new Date()) + ' Peer ' + connection.remoteAddress + ' disconnected. '+"Connection ID: " + connection.id);

// Make sure to remove closed connections from the global pool

delete connections[connection.id];

});

// Broadcast to all open connections

function broadcast(data) {

Object.keys(connections).forEach(function(key) {

var connection = connections[key];

if (connection.connected) {

connection.send(data);

}

});

}

// Send a message to a connection by its connectionID

function sendToConnectionId(connectionID, data) {

var connection = connections[connectionID];

if (connection && connection.connected) {

connection.send(data);

}

First, you need to have nodejs installed.
Save the above code into websock-server\index.js
Then, in your terminal/cmd, type npm install websocket@1.0.3 to install the nodejs websocket library.
Make sure your port 8080 is not occupied by other program as I am using port 8080 in this example.
Next, in your terminal/cmd, cd into the folder and type node index.js

As you can see, I made some modification to the index.js file:

It now do not take in a protocol
Able to do broadcast by keeping a list of connected clients
Modified on request and close request to support the clients tracking function
Instead of parrot back the same msg, it is now broadcasting any sender’s msg to everyone. More like how a chat room behave

Client Part:

For the client part, I going to create 2 interface, one for sending and receiving chat msg (index.htm), another for receiving chat msg only (logger.htm).

You will need to change the Server IP in it into yours (ws://192.168.0.200:8080)
The code is pretty simple, everything is self described.
So now i can open the index.htm and type a msg, and it will appear on the space below the input box, as well as in logger.htm
I can even put index.htm into phonegap (need to provide option for user to enter the Server IP) and it can serve as a ‘controller’ while logger.htm can be modified to be a ‘receiver’

Index.html code

<html lang="en">
<head>
    <title>Node Based Echo</title>
    <script src="js/jquery-1.6.2.min.js" type="text/javascript"></script>
    <script src="js/jquery.websocket-0.0.1.js" type="text/javascript"></script>
    <script src="js/jquery.json.min.js" type="text/javascript"></script>
</head>
<body>
    <script type="text/javascript">
 
        // sends a message to the websocket server
        function sendToServer() {
			ws.send('say', '{ messageTextA: ' + $('#echoText').val() + ' }');
            //ws.send('krakenmsgB', '{ messageTextB: ' + $('#echoText').val() + ' }');
        }
 
        // set-up web socket
        var ws = $.websocket("ws://192.168.0.200:8080/", {
            open: function () { },
            close: function () { alert('websocket has been closed'); },
            events: {
                say: function (e) { $('#returnText').append(e.data + "<br/>"); },
            }
        });
 
    </script>
    <div>
        <div style="float: left; clear: left; padding-top: 2px;">
            Your text:
        </div>
        <div style="float: left; padding-left: 20px;">
            <input type="text" id="echoText" style="width: 150px;" required />
        </div>
        <div style="clear: left;">
            <input type="button" onclick="javascript:sendToServer();" value="Send" />
        </div>
        <div id="returnText" style="clear: left; height: 200px; padding-top: 30px;">
        </div>
    </div>
</body>
</html>

<head>

<title>Node Based Echo</title>

</head>

<body>

// sends a message to the websocket server

function sendToServer() {

ws.send('say', '{ messageTextA: ' + $('#echoText').val() + ' }');

//ws.send('krakenmsgB', '{ messageTextB: ' + $('#echoText').val() + ' }');

}

// set-up web socket

var ws = $.websocket("ws://192.168.0.200:8080/", {

open: function () { },

close: function () { alert('websocket has been closed'); },

events: {

say: function (e) { $('#returnText').append(e.data + "<br/>"); },

}

});

</script>

<div>

Your text:

</div>

</div>

</div>

</div>

</body>

</html>

Finally, to save your day, I put up the full source code here at https://github.com/exiang/websock. All the best and have fun!

YS Tech Share

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Monthly Archives: August 2014

WebSocket Server & Mobile Client

Server part:

Client Part: