A simple example of setting-up dynamic "rooms" for socket.io clients to join

client.js

// set-up a connection between the client and the server
var socket = io.connect();

// let's assume that the client page, once rendered, knows what room it wants to join
var room = "abc123";

socket.on('connect', function() {
   // Connected, let's sign-up for to receive messages for this room
   socket.emit('room', room);
});

socket.on('message', function(data) {
   console.log('Incoming message:', data);
});

server.js

// attach Socket.io to our HTTP server
io = socketio.listen(server);

// handle incoming connections from clients
io.sockets.on('connection', function(socket) {
    // once a client has connected, we expect to get a ping from them saying what room they want to join
    socket.on('room', function(room) {
        socket.join(room);
    });
});

// now, it's easy to send a message to just the clients in a given room
room = "abc123";
io.sockets.in(room).emit('message', 'what is going on, party people?');

// this message will NOT go to the client defined above
io.sockets.in('foobar').emit('message', 'anyone in this room yet?');

I think this will help a lot of people, I am just using Firebase but the concept is the same, you just find somehow the identifier of your connected user and join it automatically

// server side
const debugSocket = debug('debug')('myAppName:socket')

const Channel = IOServer(...)

const CustomerChannel =
  Channel
  .of('/customer') // I am using another channel but it doesn't not matter, just showing an example
  .on('connection', async (socket)=> {
    debugSocket('CustomerChannel: Connected')
    let currentUser = null

    // I am using firebaseToken key from the query but does not matter
    // you could switch to whichever key you want as long as it is useful
    // for find your user
    if(socket.handshake.query && socket.handshake.query.firebaseToken) {
        currentUser = await firebase.auth().verifyIdToken(socket.handshake.query.firebaseToken)
        // being fancy, make sure that currentUser is not undefined or null
       // or whatever your await function could have, that is a business rule


        // Either Firebase callback or you just do some database lookup
        // using some useful information from the token
        debugSocket(`CustomerChannel:Room:Joined: ${user.email}`)
        // Whatever the callback returns me I will use some idetifier
        // and I will use it as the ID of my room
        socket.join(user.uid)
    }

    socket.on('disconnect', (reason) => {
      if(currentUser) {
        debugSocket(`CustomerChannel:Room:Leaved: ${user.email}`)
          // Same concept here I am just disconnecting the user from his own
          // This is because you can still connected to CustomerChannel
          // but not to your room, this depends of your use case
        socket.leave(currentUser.uid)
      }
    })
  })

In the client you need to make sure that you send the query parameter when you connect to the channel

// client side
io(`/customer`, {
      query: {
        token: 'whatever' // just make sure you have the information before you connect to the channel
      }
    })

Now the second part is to send messages to specific room.

// server code

// somewhere in my backend code
// I have to have the identifier of the user to be able to send him and only him messages
// so somehow I HAVE TO HAVE `user` loaded and then I will use it `uid` which was the way
// I joined the user to his room.
CustomerChannel.to(user.uid).emit('hello', { message: 'World'})

I hope you find it useful.

Cheers.

If what you want is to connect multiple people to the same room, then just send roomId: "" in the query which somehow you had to find it before, right!? Somebody have to create specific room somehow, either you create some database that have it them or you just type the roomID whatever you do.

And then instead of user the user.uid just use the roomId and done.

After that in your backend code, somehow you HAVE TO HAVE the roomId you want to send the data to.

Would anyone know if rooms can only emit text?
I am trying to emit an image on canvas to one specific room and it won't work.
It will however work if I emit a text message.

Thank your

Hi,

I am having a room how can I add new user to the same room in socket.io. I can't find a way please help me.

Hi,

I am having a room how can I add new user to the same room in socket.io. I can't find a way please help me.

I think you can just give the same name to any new user.

In Socket When new connection join the room at that time its remove last connected socket from the room can you please help me on this if someone know ? Also didn't get any error when i debugging.

Thanks!

A great example, simple and useful. Thank you sir.

Can anyone tell me that how we can randomly adjust the sockets to different rooms at the same time not one room?

A great example, simple and useful. Thank you sir.

Can YOu tell me that how we can randomly adjust the sockets to different rooms at the same time not one room?

Thanks 👍

this example make thing simpler

great example thanks!

Anyone can tell me how to assign users from the db or active users in to specific Room. Where can we handle that?

thanks

Thank you for a great example

This is definitely helpful!
Socket.io's docs don't provide much info about this.

Yeah socket.io docs is very bad .For basic knowledge of socket.io tutorial point is best

server.js line 13 room = "abc123"; - is it hardcode? if so, it's seems to me stupid.

it's an example.

Many thanks!

Any idea on how to add other users to the room using their socketid.

In the client, how to receive only the messages of the room that was created?
Because in the way you gave as an example, the client receives any message and not just from the created room.

Thanks

How can i join room at backend with io instance and not socket instance?

How can i join room at backend with io instance and not socket instance?

Hi, I think you can, if you put your room you want to join in in the query (room:"abc123") then your server will read it upon connection
as socket.handshake.query.room;
then join the appropriate room.

Thanks!!

In the client, how to receive only the messages of the room that was created? Because in the way you gave as an example, the client receives any message and not just from the created room.

Thanks
The client will get the roomId from the server so the client will output the message to room with the roomId

Nice Tutorial, video is too good .

Is possible create dynamic rooms in socket nodejs.
Example : If i have array of socket Ids, How can I add this socket ids in that room

if i disconnect the socket , how will i know the past activities,