Socket.io - 离开房间时延迟

Question

I want to send the number of users connected to a room when a client leaves.

It seems socket.leave() has a delay.

How to do that properly? I don't like to use setTimeout()

socket.on('disconnect', function () {
  var roomsToSayGoodbye = io.sockets.manager.roomClients[socket.id];
  for (var room in roomsToSayGoodbye) {
    io.sockets.in(room).clients().length; // For example: 6
    socket.leave(room);
    io.sockets.in(room).clients().length; // Still 6!!
    // So, this is wrong -->
    io.sockets.in(room).emit('nb-connections', { num: io.sockets.in(room).clients().length });
    // <--
    // and I need this to make it work, not clean! -->
    setTimeout(function() {
      io.sockets.in(room).clients().length; // Okay, now 5
    }, 1000 );
  }
}

Answer 1

Socket.leave is asynchronous, and as such has an optional second parameter for a callback, so you could do this:

socket.leave(room, function() {
    io.sockets.in(room).emit('nb-connections', { num: io.sockets.in(room).clients().length });
    // this should be the number you want
});

...which should report the correct number

This requires the latest version of Socket.io (version 1.0) which has not yet been published to npm (as of 11/14/2013). To use it, you'd need to include the following in your package.json:

"dependencies": {
    "socket.io": "git://github.com/LearnBoost/socket.io.git#1.0"
}

...which should pull in the 1.0 branch (caveat stability).

Answer 2

io.sockets.manager.roomClients[socket.id] returns a list of rooms with leading '/' character in all room names.

The Socket.io Wiki says : "This is used internally and does not have to be referenced when joining, leaving or emitting to rooms."

So, When you leave a room, make sure that the room name does not contain the leading '/' character. You can try socket.leave(room.replace('/',''));

Not tested, but should do the trick.

Answer 3

You can check working example of displaying number of clients in this repository. It is developed for socket.io v1.0 and express v4.0.

https://github.com/theoctal/livenote