Hello Raspberry Pi: Node.js + Socket.IO: share common status for all clients

Sunday, March 16, 2014

Node.js + Socket.IO: share common status for all clients

Last post have individual status for each client. In this example, all client share one common status, that means client A click to change status, not only his button text will change, but also all other clients will change.

In this example:

All clients share a common status, commonStatus.
Will info new client his id, socket.id.
Server will broadcast all clients if any new client connected, io.sockets.emit(). Also info the number of client connected, io.sockets.clients().length.
Info the current common status to new connected client.
Info all clients if a client disconnected, socket.on('disconnect', function).

app.js

//$ npm install socket.io

var app = require('http').createServer(handler)
  , io = require('socket.io').listen(app)
  , fs = require('fs')

//All clients have a common status
var commonStatus = 'ON';

app.listen(8080);

function handler (req, res) {
  fs.readFile(__dirname + '/index.html',
  function (err, data) {
    if (err) {
      res.writeHead(500);
      return res.end('Error loading index.html');
    }

    res.writeHead(200);
    res.end(data);
  });
}

io.sockets.on('connection', function (socket) {
    
    //Send client with his socket id
    socket.emit('your id', 
        { id: socket.id});
    
    //Info all clients a new client caaonnected
    io.sockets.emit('on connection', 
        { client: socket.id,
          clientCount: io.sockets.clients().length,
        });
        
    //Set the current common status to the new client
    socket.emit('ack button status', { status: commonStatus });
    
    socket.on('button update event', function (data) {
        console.log(data.status);
        
        //acknowledge with inverted status, 
        //to toggle button text in client
        if(data.status == 'ON'){
            console.log("ON->OFF");
            commonStatus = 'OFF';
            
        }else{
            console.log("OFF->ON");
            commonStatus = 'ON';
        }
        io.sockets.emit('ack button status', 
            { status: commonStatus,
              by: socket.id
            });
    });
    
    //Info all clients if this client disconnect
    socket.on('disconnect', function () {
        io.sockets.emit('on disconnect', 
            { client: socket.id,
              clientCount: io.sockets.clients().length-1,
            });
    });
});

index.html

<html>
<head></head>
<body>
<hi>Test Node.js with socket.io</hi>
<form action="">
<input type="button" id="buttonToggle" value="ON" style="color:blue"
       onclick="toggle(this);">
</form>
<script src="/socket.io/socket.io.js"></script>
<script>
var socket = io.connect(document.location.href);
var myId;

socket.on('on connection', function (data) {
    console.log("on connection: " + data.client);
    console.log("Number of client connected: " + data.clientCount);
});

socket.on('on disconnect',function(data) {
    console.log("on disconnect: " + data.client);
    console.log("Number of client connected: " + data.clientCount);
});

socket.on('your id',function(data) {
    console.log("your id: " + data.id);
    myId = data.id;
});

socket.on('ack button status', function (data) {
    console.log("status: " + data.status);
    
    if(myId==data.by){
        console.log("by YOU");
    }else{
        console.log("by: " + data.by);
    }
    
    if(data.status =='ON'){
        document.getElementById("buttonToggle").value="ON";
    }else{
        document.getElementById("buttonToggle").value="OFF";
    }
});

function toggle(button)
{
 if(document.getElementById("buttonToggle").value=="OFF"){
  socket.emit('button update event', { status: 'OFF' });
 }
 else if(document.getElementById("buttonToggle").value=="ON"){
  socket.emit('button update event', { status: 'ON' });
 }
}
</script>

</body>
</html>

Sunday, March 16, 2014

Node.js + Socket.IO: share common status for all clients

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