Emit to Socket IO socket.id

Question

I am trying to emit to a particular socket ID:

socket(user[playID]).emit('correct', data);

But I'm getting:

TypeError: object is not a function

if I log out user[playID] I do get a valid socket ID.

Appreciated!

Here is my setup in case I'm missing something:.

// Tell Socket.io to pay attention
servio  = io.listen(server);

// Tell HTTP Server to begin listening for connections on port 3250
sock    = server.listen(3250);

score 12 · Accepted Answer · edited May 23 '17 at 12:25

12

This should do it

servio.sockets.socket(id).emit('hello');

This answer covers the same/similar topic. In short, consider keeping a reference to the connected clients yourself and emit to them as desired, rather than relying on socket.io's internals, which could change.

edited May 23 '17 at 12:25

Community

1
1

answered Oct 14 '13 at 11:19

Jaz Lalli

660
7
15

score 3 · Answer 2 · answered Aug 29 '15 at 06:07

Per http://socket.io/docs/rooms-and-namespaces/,

Each Socket in Socket.IO is identified by a random, unguessable, unique identifier Socket#id. For your convenience, each socket automatically joins a room identified by this id.

You emit to a room like:

io.to('some room').emit('some event')

If you want to emit to just a specific socket.id, just replace 'some room' with the associated id.

score 2 · Answer 3 · answered Oct 13 '13 at 04:09

Another way to do this is:

var players = [];

io.sockets.on('connection', function(socket){

    socket.on('skt_init', function (data) {
            var player = new Object();
            player.id = data.id;
            player.socket = socket.id;
            players.push(player);
    });

    socket.on('disconnect', function() {        
        var len = 0;

        for(var i=0, len=players.length; i<len; ++i ) {
            var p = players[i];

            if(p.socket == socket.id){
                players.splice(i,1);
                break;
            }
        }
    });

    socket.on('skt_event', function(data, id_player){
        var len = 0;

        for(var i=0, len=players.length; i<len; ++i ) {
            var p = players[i];
            if(p.id == id_player){
                io.sockets.socket(p.socket).emit('correct', data);
                break;
            }
        }
    });

Hope that helps somewhat.

score 2 · Answer 4 · answered Mar 19 '16 at 00:24

2

UPDATE: in socket.io-1.4 you have to prepend "/#" to socket id ( very frustrating that it doesnt work now). you can also view all connected sockets from backend as io.sockets.connected

io.to( "/#" + socket_id).emit("event_name",{data:true})

answered Mar 19 '16 at 00:24

Alex Gulakov

87
1
5

robertklep · Answer 5 · 2013-10-12T13:42:01.073

0

This should work:

servio.sockets.sockets[playId].emit(...)

edited Oct 12 '13 at 13:42

answered Oct 12 '13 at 12:07

robertklep

198,204
35
394
381

No I still have the same problem. – Matthew Starkey Oct 12 '13 at 15:46

score 0 · Answer 6 · answered Apr 15 '15 at 20:34

Since socket.io doesn't provide a stable API to get the socket from a socket's ID, you can simply (and easily) keep track of them with an object keyed by socket IDs.

sockets_by_id = {}

io.on "connection", (socket)->
    sockets_by_id[socket.id] = socket

sockets_by_id[socket_id].emit event, data...

(^CoffeeScript^)

Emit to Socket IO socket.id

6 Answers6

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