Properly getting a socket by ID

I’ve asked on IRC what the proper way is to get a socket by id from the normal namespace. Supposedly it would be io.sockets.client(id). Unfortunately, this method does not exist. I figured it’d be a typo, and it should be io.sockets.clients(id). However, the clients method expects a room and then returns an array of all sockets in that room.

Thus, one could get a socket by id like so:

function getSocketById(id) {
    var clients = io.sockets.clients(),
        client  = null;
    clients.forEach(function(_client) {
        if (_client.id === id) return (client = _client);
    });
    return client;
}

This is obviously rather excessive. A much more efficient way would be to access the socket by id through a library (an object where id is the key).

From the source, another way to access a socket by id is io.sockets.socket(id);. Unfortunately, there are 2 problems here:

• the method is flagged private
• the method creates a new socket when the given id does not exist

Thus, this method cannot be used as passing an invalid or non-existant id would trigger the creation of a dead socket.

Is there no proper way to get a client from a namespace by id at the moment?

[fselcukcan]

io.sockets.sockets is an array of sockets, so you can

var socket = _.findWhere(io.sockets.sockets, {id: 'mySocketId'});

using underscore or

var socket;
for (var i = 0; i < io.sockets.sockets; i += 1) {
  if (io.sockets.sockets[i].id === 'mySocketId') {
    socket = io.sockets.sockets[i];
  }
}

more general. Have in mind that io.sockets is the “/” namespace. For specific namespace: io.of(‘/ns’).sockets.

@romelperez But whole this comments thread is based on a comment of @tommedema stating that using forEach in your case some underscore.js function, is excessive. Not an array but a hash would be more efficient or convenient.

[romelperez]

io.sockets.sockets is an array of sockets, so you can

var socket = _.findWhere(io.sockets.sockets, {id: 'mySocketId'});

using underscore or

var socket;
for (var i = 0; i < io.sockets.sockets; i += 1) {
  if (io.sockets.sockets[i].id === 'mySocketId') {
    socket = io.sockets.sockets[i];
  }
}

more general. Have in mind that io.sockets is the “/” namespace. For specific namespace: io.of(‘/ns’).sockets.