Socket IO Rooms: Get list of clients in specific room

Question

I'm trying to display a list of clients in a specific room. I just want to show their username, and not their socket id.

This where I'm at:

socket.set('nickname', "Earl");  
socket.join('chatroom1');
console.log('User joined chat room 1);

var roster = io.sockets.clients('chatroom1');
for ( i in roster )
{
   console.log('Username: ' + roster[i]);   
}

Haven't had any luck getting it to list Socket IDs or anything. Would like it to return the nicknames however.

score 77 · Answer 1 · edited Jan 29 '21 at 01:44

In socket.IO 3.x

New to version 3.x is that connected is renamed to sockets and is now an ES6 Map on namespaces. On rooms sockets is an ES6 Set of client ids.

//this is an ES6 Set of all client ids in the room
const clients = io.sockets.adapter.rooms.get('Room Name');

//to get the number of clients in this room
const numClients = clients ? clients.size : 0;

//to just emit the same event to all members of a room
io.to('Room Name').emit('new event', 'Updates');

for (const clientId of clients ) {

     //this is the socket of each client in the room.
     const clientSocket = io.sockets.sockets.get(clientId);

     //you can do whatever you need with this
     clientSocket.leave('Other Room')

}

In socket.IO 1.x through 2.x

Please refer the following answer: Get list of all clients in specific room. Replicated below with some modifications:

const clients = io.sockets.adapter.rooms['Room Name'].sockets;   

//to get the number of clients in this room
const numClients = clients ? Object.keys(clients).length : 0;

//to just emit the same event to all members of a room
io.to('Room Name').emit('new event', 'Updates');

for (const clientId in clients ) {

     //this is the socket of each client in the room.
     const clientSocket = io.sockets.connected[clientId];

     //you can do whatever you need with this
     clientSocket.leave('Other Room')
}

I need something > 1.0 but something you clearly indicate this doesn't work on 1.0 above, no reason for the downvote. Have a +1 to balance it out :p. — StackOverflowed, Mar 12 '16 at 14:39

score 23 · Answer 2 · answered May 10 '18 at 10:20

23

Instead of going deep in socket/io object , You can use simple and standard way :

io.in(room_name).clients((err , clients) => {
    // clients will be array of socket ids , currently available in given room
});

For more detail DO READ

answered May 10 '18 at 10:20

Vivek Doshi

56,649
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How can I use async and await with this? – Muhammad Usama Mashkoor Jun 18 '20 at 18:59
6

Note that this solution doesn't work with socket.IO v3 or newer. – Samuli Asmala Mar 26 '21 at 07:08

score 19 · Accepted Answer · edited Jun 20 '20 at 09:12

19

Just a few things.

when you have the socket you can then set the properties like: socket.nickname = 'Earl'; later to use the save property for example in a console log: console.log(socket.nickname);
you where missing a closing quote (') in your:

console.log('User joined chat room 1);
Im not entirely sure about your loop.

Below is the amended code should help you out a bit, also be aware the loop i am using below is asynchronous and this may effect how you handle data transfers.

socket.nickname = 'Earl';
socket.join('chatroom1');

console.log('User joined chat room 1');
    
var roster = io.sockets.clients('chatroom1');
        
roster.forEach(function(client) {
    console.log('Username: ' + client.nickname);
});

to help you out more i would need to see all your code as this does not give me context.

edited Jun 20 '20 at 09:12

Community

1
1

answered Aug 07 '13 at 06:59

Jacob Squires

507
4
8

2

Does "io.sockets.clients('chatroom1')" work in nodejs v1.0 & above? – Sony Mathew Jul 24 '14 at 13:51
1

Hello, I got an error in io.sockets.clients('roomname'), mysocket version is 2.2.0 – Md Alamin Feb 01 '19 at 08:40
5

While this is the accepted answer, it does not work for versions greater than socket.io 1.0. – technogeek1995 May 10 '19 at 16:25
2

this method does't exists anymore – Vikas Kandari May 22 '20 at 15:56
method giving error : clients is not a function – Sachin May 22 '21 at 11:23

score 16 · Answer 4 · answered Jul 30 '21 at 04:30

16

For v4 I used this method fetchSockets()

Example :

let roomUsers=await io.in(`room-id`).fetchSockets()

see documentation here : https://socket.io/docs/v3/migrating-from-3-x-to-4-0/#Additional-utility-methods

answered Jul 30 '21 at 04:30

Schnitter

192
3
6

score 5 · Answer 5 · edited Dec 07 '19 at 23:21

All the answers above and the one here socket.io get rooms which socket is currently in or here Socket.IO - how do I get a list of connected sockets/clients? were either incorrect or incomplete if you use 2.0.

In 2.0, io.sockets.manager and io.sockets.clients don't exist anymore.
Without using namespace, the following 3 parameters can all get sockets in a specific room.

socket.adapter.rooms;

io.sockets.adapter.rooms;

io.sockets.adapter.sids; // the socket.id array
With namespace (I used "cs" here), io.sockets.adapter.rooms will give a quite confusing result and the result socket.adapter.rooms gives is correct:

/* socket.adapter.rooms give: */

{
  "/cs#v561bgPlss6ELZIZAAAB": {
    "sockets": {
      "/cs#v561bgPlss6ELZIZAAAB": true
    },
    "length": 1
  },
  "a room xxx": {"sockets": {
    "/cs#v561bgPlss6ELZIZAAAB": true
  },
  "length": 1
  }
}

/* io.sockets.adapter.rooms give: a sid without namespace*/

{
  "v561bgPlss6ELZIZAAAB": {
    "sockets": {
      "v561bgPlss6ELZIZAAAB": true
    }, "length": 1
  }
}

Note: the default room is this: "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."

I only tried memory adapter so far, have not tried redis-adapter.

score 3 · Answer 6 · answered Dec 10 '20 at 19:20

For socket.IO v3 there's a breaking change here:

Namespace.clients() is renamed to Namespace.allSockets() and now returns a Promise.

BEFORE:

// all sockets in the "chat" namespace and in the "general" room
io.of("/chat").in("general").clients((error, clients) => {
  console.log(clients); // => [Anw2LatarvGVVXEIAAAD]
});

Now (v3):

// all sockets in the "chat" namespace and in the "general" room
const ids = await io.of("/chat").in("general").allSockets();

Source

In case you're not so familiar with socket.IO, it might be good to know that instead of io.of("/chat") you can write io to use the default namespace.

This also works in Socket.IO v4. To be precise, the example code above returns a Set of socket IDs, not the actual Socket objects. `io.of('/').sockets` can be used to get a Map of Socket instances connected to a namespace so `io.of('/').sockets.get(socketId)` gets the Socket instance matching the id. — Samuli Asmala, Mar 26 '21 at 07:45

score 3 · Answer 7 · answered Nov 03 '21 at 13:08

3

For Socket v.4 correct syntax would be:

const sockets = await io.in("room1").fetchSockets();

https://socket.io/docs/v4/server-api/#namespacefetchsockets

answered Nov 03 '21 at 13:08

nojitsi

351
3
13

score 3 · Answer 8 · answered Apr 06 '22 at 13:19

3

In socket.IO 4.x

const getConnectedUserIdList = async () => {
  let connectedUsers = [];
  let roomUsers = await io.in(`members`).fetchSockets();
  roomUsers.forEach((obj) => {
    connectedUsers.push(obj.request.user.id);
  });
  return connectedUsers;
};

answered Apr 06 '22 at 13:19

Nijat Aliyev

558
6
15

1

with v4.7.2 and above, it is now _obj.id_ – Yash Mhatre Aug 15 '23 at 18:10

score 2 · Answer 9 · answered Jun 01 '20 at 14:10

socket.io ^ 2.0

function getRoomClients(room) {
  return new Promise((resolve, reject) => {
    io.of('/').in(room).clients((error, clients) => {
      resolve(clients);
    });
  });
}

...
const clients = await getRoomClients('hello-world');
console.log(clients);

Output

[ '9L47TWua75nkL_0qAAAA',
'tVDBzLjhPRNdgkZdAAAB',
'fHjm2kxKWjh0wUAKAAAC' ]

score 2 · Answer 10 · answered Dec 17 '20 at 10:12

From Socket.io v3, rooms is now a protected property of Adapter so you won't be able to access it via io.sockets.adapter.rooms.

Instead use:

const clientsInRoom = await io.in(roomName).allSockets()

OR for multiple rooms

const clientsInRooms = await io.sockets.adapter.sockets(new Set([roomName, roomName2]))

Ezzat · Answer 11 · 2018-05-26T05:35:34.473

For Socket.io greater than v1.0 and node v6.0+ use the following code:

function getSockets(room) { // will return all sockets with room name
  return Object.entries(io.sockets.adapter.rooms[room] === undefined ?
  {} : io.sockets.adapter.rooms[room].sockets )
    .filter(([id, status]) => status) // get only status = true sockets 
    .map(([id]) => io.sockets.connected[id])
}

If you want to emit something to them , use this :

getSockets('room name').forEach(socket => socket.emit('event name', data))

score 1 · Answer 12 · answered Jan 05 '21 at 11:53

This solution is for

socket.io : "3.0.4"
socket.io-redis : "6.0.1"

import these first

const redis = require('socket.io-redis');
io.adapter(redis({ host: 'localhost', port: 6379 }));

socket.on('create or join', function(room) {
    log('Received request to create or join room ' + room);

    //var clientsInRoom = io.sockets.adapter.rooms[room];
    
    mapObject = io.sockets.adapter.rooms // return Map Js Object
    clientsInRoom = new Set(mapObject.get(room))
  
    var numClients = clientsInRoom ? clientsInRoom.size : 0;
    log('Room ' + room + ' now has ' + numClients + ' client(s)');

https://socket.io/docs/v3/using-multiple-nodes/#The-Redis-adapter https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/get

Thanks, this is the only working solution as of August 2022 for me. — The Grindfather, Aug 17 '22 at 00:07

score 0 · Answer 13 · answered Nov 23 '18 at 17:02

I just logged all sockets in a room to the console, you can do whatever you like with them...

const socketsInRoom = io.adapter.rooms[room_name];

    /*Collect all participants in room*/
    for(let participant in socketsInRoom){
        for(let socketId in socketsInRoom[participant]){
            console.log(socketId)
        }
    }

score 0 · Answer 14 · edited Jan 01 '21 at 08:59

0

socket.io ^2.2.0

const socket = io(url)

socket.on('connection', client => {
  socket.of('/').in("some_room_name").clients((err, clients) => {
    console.log(clients) // an array of socket ids
  })
})

edited Jan 01 '21 at 08:59

Tomer Shetah

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answered Jun 22 '19 at 20:46

Isaac Pak

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How can I use async and await with this? – Muhammad Usama Mashkoor Jun 18 '20 at 19:01
1

A trivial answer would be to wrap the whole thing in an async function and await the callbacks. This might help: https://stackoverflow.com/questions/47035243/with-socketio-is-it-possible-to-use-async-with-socket-on – Isaac Pak Jun 18 '20 at 21:01

score 0 · Answer 15 · answered Jan 01 '21 at 07:09

you can use the adapter method on io object like

io.sockets.adapter.rooms.get("chatroom1")

this will return the list of connected clients in the particular room. io.sockets.adapter.rooms this is a map off all clients connected to rooms with room name as keys and the connected clients are the values of the room key. map functions are applicable .

score 0 · Answer 16 · answered May 07 '21 at 04:12

0

Since I have found very little on how to get the rooms inside a specific namespace, here it is in case anyone is wondering :

io.of(namespaceName).adapter.rooms;

answered May 07 '21 at 04:12

PedroMiotti

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score 0 · Answer 17 · answered Apr 07 '22 at 07:32

0

let sockets = await io
              .of("/namespace")
              .in(ROOM_NAME)
              .allSockets();

you can get length of connected clients via

console.log(receiver.size);

answered Apr 07 '22 at 07:32

Parth Mahida

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5
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score -3 · Answer 18 · answered Aug 07 '13 at 07:58

-3

You can create an array object of user collection as

var users = {};

then on server side you can add it as new user when you connect

socket.on('new-user', function (username) {
    users[username] = username;
});

while displaying the users, you can loop the "users" object

On Client side

var socket = io.connect();

socket.on('connect', function () {
    socket.emit('new-user', 'username');
});

answered Aug 07 '13 at 07:58

Jeet

717
6
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seriously, you're gonna send the username from the client side instead of checking the cookies and stuff? isn't it extremely easily fakable? – Steel Brain Sep 08 '14 at 07:41
I would recommend using the socket.handshake.query with middleware to authenticate, then store that token/username as a socket property to refer to from the server-side so it will just work. – King Friday Aug 16 '17 at 18:12

Socket IO Rooms: Get list of clients in specific room

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