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?');

Great example! Thanks!

Please write example for "io.sockets.clients(room)", how can i see who in room online ??

Your example is so helpfull but I have a question. How can I take off a client?

I found an ansewer of my question in this post:https://github.com/LearnBoost/socket.io/wiki/Rooms

and also can help to hyperprodify with their question.

Regards

are the clients inside the room stored as Array? how can I access the list of clients in a certain room and see who they are?

Carter, this is awesome. Is it possible to do this with Socket.io namespaces?

Just wanted to say thank you for simplifying it! Totally get it know.

A huge "Thank you!" from myself as well! I've been struggling to achieve this for quite some time with no result... All the other tutorials or articles I've read don't cover the basic not even nearly as well! Now I can finally advance with my project!

For those who wonder how to leave the previous room, if a active user joins (switches to) another room, try this:

server.js

socket.on('room', function(room){
    if(socket.room)
        socket.leave(socket.room);

    socket.room = room;
    socket.join(room);
});

a customer can be in more than one room ?

Yes, users can be in any number of rooms at once

Great example... Thanks :)

Great. It helps a lot. Thanks.

This is helpful!

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Thanks for this. ☺

Thanks, this helped me!

Thank you! Super helpful!

Thanks very much for this. =)

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

Damm ! That Simple.

and where is the dynamic example?

Very useful, thanks~

Created 4 years ago

Still useful. Thanks!

Very useful, clear....thank you so much..

Thanks !

You make it look so easy

Thanks :)

Cheers!

Thanks 👍

THANK YOU!

thank you :)

Does this work in 1.5?

Thank you for the clear example

thank you so much

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

@daryn-k It's only there as an example. You can swap this out for any dynamic room ID method.

Hi everyone!
I can ask a question?
How to Client can join multiple room and receive 2 notifications the same time for different two rooms.

Can we joined room permanently .... actually i am developing node + socket application as gameserver and client is unity ... and i join p1 to room when he invite to p2 ... and p2 was joined when he accept p1 invitation ! after that i had emmited to that joined room >> it works perfectly !
But after i had emmited function to this room .. in unity i had change scene of both connected clients and in that scene there is a one button for both p1 and p2 to click start game ... when i click this button ... it will emit to server to start game for both clients ! but problem is when i emit to that room .... no clients are connected .... so i wanna join permanently !
Thankx for any advance ...

Is there any way to assign some data to a room? So that it will be shared with other sockets by reference? For example if two players were in a room and played tic tac toe and I wanted to save game board state somewhere.

Great example! Life saver

how to perform same operation in android

thanks

thanks !

how can we create a dynamically room for particular 2 player.
ex : player - 1 and player - 2 connect in Room-1 when come player - 3 than create a room 2 and join they and check the player in each room.
if Room-1 connect player - 1 so player -2 connect with room-1.
when connect player-3 create new room-2 for that.

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