socket.io get rooms which socket is currently in

Question

Is it possible to get rooms which socket is currently in, without calling

io.sockets.clients(roomName)

for every room name and looking for

Answer 1

When using a non-default adapter, such as socket.io-redis, socket.rooms doesn't seem to do the trick. The way I managed to get the rooms for a specific client without looping was to use io.sockets.adapter.sids[socket.id], which returns the rooms as an object.

{ 'R-ZRgSf7h4wfPatcAAAC': true, ROOM: true, ROOM_2: true }

Note that this doesn't list sockets on other processes, though!

socket.io v1.3.7, socket.io-redis 1.0.0

Answer 2

You can save room in socket itself when it joins a room

// join room
socket.join(room);

// update socket's rooms
if (socket.rooms) {
    socket.rooms.push(room);
} else {
    socket.rooms = [room];
}

Later you can retrieve all rooms that the socket is in by simply

socket.rooms

From the Server API documentation:

socket.rooms (object)
A hash of strings identifying the rooms this client is in, indexed by room name.

https://socket.io/docs/server-api/#socket-rooms

Answer 3

In socket.io version 1+ the syntax is:

socket.rooms

Answer 4

Cross-compatible way

var rooms = Object.keys(io.sockets.adapter.sids[socket.id]);
// returns [socket.id, 'room-x'] or [socket.id, 'room-1', 'room-2', ..., 'room-x']

Answer 5

Update: Socket.io 3.0 Released

---

With 3.x Socket.rooms is Set now, which means that values in the rooms may only occur once.

Structure example: Set(4) {"<socket ID>", "room1", "room2", "room3"}

io.on("connect", (socket) => {
  console.log(socket.rooms); // Set { <socket.id> }
  socket.join("room1");
  console.log(socket.rooms); // Set { <socket.id>, "room1" }
});

To check for specific room:

socket.rooms.has("room1"); // true

More about Set and available methods: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set

Migration Docs: https://socket.io/docs/migrating-from-2-x-to-3-0/

Answer 6

Version 1.7.3, socket.rooms contains socket.id, so remove it and get the list of rooms:

Object.keys(socket.rooms).filter(item => item!=socket.id);

In other version, you can print the socket and find the rooms.