What is the proper way to manage multiple chat rooms with socket.io?

Question

What is the proper way to manage multiple chat rooms with socket.io?

So on the server there would be something like:

io.sockets.on('connection', function (socket) {
  socket.on('message', function (data) {
    socket.broadcast.emit('receive', data);
  });
});

Now this would work fine for one room, as it broadcasts the message out to all who are connected. How do you send messages to people who are in specific chat rooms though?

Add .of('/chat/room_name')? Or store an array of everybody in a room?

Answer 1

Socket.IO v0.7 now gives you one Socket per namespace you define:

var room1 = io.connect('/room1');
room1.on('message', function () {
    // chat socket messages
});
room1.on('disconnect', function () {
    // chat disconnect event
});

var room2 = io.connect('/room2');
room2.on('message', function () {
    // chat socket messages
});
room2.on('disconnect', function () {
    // chat disconnect event
});

With different sockets, you can selectively send to the specific namespace you would like.

Socket.IO v0.7 also has concept of "room"

io.sockets.on('connection', function (socket) {
  socket.join('a room');
  socket.broadcast.to('a room').send('im here');
  io.sockets.in('some other room').emit('hi');
});

Source: http://socket.io/#announcement

Answer 2

Update: Both Now.js and Bridge are now dead, see now.js dead and bridge dead. Socket.io seems to have adopted the callback feature as of v0.9, which is a good step forward.

While it isn't directly Socket.io related, Now.js (a higher level abstraction ontop of Socket.io) supports groups - http://nowjs.com/doc

They have a multi-room-chat example in their offocial repo here: https://github.com/Flotype/now/blob/master/examples/multiroomchat_example/multiroomchat_server.js