Sending message to specific client with socket.io and empty message queue

Question

I´m going crazy with socket.io! Documentation is so bad it's simply not true.

I want to send a feedback to specific client over socket.io

My server side looks like this:

app.get('/upload', requiresLogin, function(request, response) {
    response.render('upload/index.jade');
    io.sockets.on('connection', function (socket) {
        console.log('SOCKET ID ' + socket.id);
        io.sockets.socket(socket.id).emit('new', 'hello');
    });
});

and the client side looks like this:

$(document).ready(function() {
    var socket = io.connect('http://localhost:80/socket.io/socket.io.js');
    socket.on('new', function (data) { 
        console.log(socket.id);
        console.log(data); 
        //$('#state').html(data.status);
    });
});

but the client does simply nothing. I have tried nearly everything. Can someone tell me what I am doing wrong, please! :(

Answer 1

to send a message to a specific client save every one that connects to the server in an Object.

var socketio = require('socket.io');
var clients = {};
var io = socketio.listen(app);

io.sockets.on('connection', function (socket) {
  clients[socket.id] = socket;
});

then you can later do something like this:

var socket = clients[sId];
socket.emit('show', {});

Answer 2

A couple of ways to send feedback to a specific client over socket.io include:

• As stated by pkyeck, save all clients to an Object, so you can send to these specific clients later in your route handlers, e.g.:

  var sessionsConnections = {};
  sio.on('connection', function (socket) {
    // do all the session stuff
    sessionsConnections[socket.handshake.sessionID] = socket;
  });
  

• or, use socket.io's built in support for rooms - subscribe each client to a room on connection and send via this room within route handlers, e.g.:

  sio.on('connection', function (socket) {
    // do all the session stuff
    socket.join(socket.handshake.sessionID);
    // socket.io will leave the room upon disconnect
  });
  
  app.get('/', function (req, res) {
    sio.sockets.in(req.sessionID).send('Man, good to see you back!');
  });
  

Acknowledgement:

http://www.danielbaulig.de/socket-ioexpress/#comment-1158

Note that both these example solutions assume that socket.io and express have been configured to use the same session store and hence refer to the same session objects. See the links above and below for more details on achieving this:

https://github.com/LearnBoost/socket.io/wiki/Authorizing

Answer 3

2 things

1) You should really place your io.sockets.on(..) outside your app/update route to prevent adding multiple listeners for clients.

2) io.sockets.socket(id); should not be used, it should have been socket.emit('new', 'hello')

Answer 4

In socket.io 1.0, this is how it would work. It may work for lower versions, but I cannot guarantee it.

socket.to(socket_id_here).emit('new', 'hello');

This works because socket.io automatically adds a socket to a room with the socket's id on connection.

Also, if you plan to upgrade to version 1.0, there are a lot of changes to the api, so you'll sometimes have to change some code to make it work in 1.0.

Answer 5

The correct way to do this in Socket.io 1.0+ is:

io.to(users_socket_id).emit('new', 'hello');

You can also substitute a room name for 'users_socket_id' to emit to a specific socket.io room.

Answer 6

First of all, you cannot use socket.id on client side.

And then change the line

var socket = io.connect('http://localhost:80/socket.io/socket.io.js');

to

var socket = io.connect('http://localhost:80/');

Answer 7

I believe io.sockets.socket has been removed and has been a problem in Socket.IO (https://github.com/socketio/socket.io/issues/1618).

You can use io.sockets.connected[socket.id] and store the socket.id to reference with the user via username:

var usernames = {};
usernames[username] = socket.id;
// Sending the message
io.sockets.connected[usernames[username]].emit(...);

I don't see it anywhere on the documentation so I can see how this hasn't been answered. Also, if you don't have any reference via usernames, you can instead try:

users[socket.id] = socket.id;

to duplicate the key and value for easy access.

There is also possibly another way by using io.clients as described below, but I haven't used that method.

OTHER SOLUTION: Send message to specific client with socket.io and node.js

Answer 8

Have you tried using?

var socket = io.connect('http://localhost:80/');

Answer 9

i tired with the latest version of node and socket.io below i am going to post complete code

  <ul id="messages"></ul>
<form action="">
  <input id="id1"  /><button>Send</button>
</form>
<script src="https://cdn.socket.io/socket.io-1.2.0.js"></script>
<script src="http://code.jquery.com/jquery-1.11.1.js"></script>
<script>

  var io = io.connect();
  $('form').submit(function(){
    io.emit('drumevent', $('#id1').val());
    $('#id1').val('');
    return false;
  });
  io.on('drumevent', function(msg){
  console.log(msg);



    $('#messages').append($('<li></li>').text(msg.message+'    quantity = '+msg.quantity));
  });
</script>

server side code

  var usernames = {};io.on('connection', function(socket){usernames["username"] = socket.id;
socket.on('drumevent', function(msg){     
var socketId = socket.id;io.to(socketId).emit('drumevent', data);