How to send events/messages to specific clients in node.js using Socket.io?

Question

i'm working on a Node.js app in which we are using socket.io for sending and receiving events/messages to clients. Initially it is sending events to clients using the following statement.

io.sockets.emit('SequenceLoad', data);

But now i want to send events only to specific clients using client specific sockets. I have searched alot regarding this, found some ways but none of them seems to work, found on various SO posts.

Here is the code that i have tried:

const io = require('socket.io')(http);
var socketsCollection = [];
io.on('connection', function (socket) {

  //Saving socket id's for sending events to specific sockets based on their ids
  socketsCollection.push(socket.id);
  socket.on('SequenceLoadServer', function (data) {
     // logger.info('Socket Server | Event: sequenceLoadServer with socket server. \n Data:'+ data);
     console.log("In APP.js for SequenceLoadServer event");
     console.log("Socket Id :" + socket.id);
     var socketId = null;
     setTimeout(function () {
        for (var item of socketsCollection) {
           if(item == socket.id){
              socketId= item;
              break;   
           }
        }
        console.log("Socket after searching Id :" + socketId);
        io.sockets.emit('SequenceLoad', data);   -> This works at the moment

        //Tried the following ways as well but none of them worked 

        //io.sockets.connected[socketId].emit('SequenceLoad', data);
        //io.sockets.socket(socketId).emit('SequenceLoad', data); 
        //io.to(socketId).emit('SequenceLoad', data);
        //io.to('/#' + socketId).emit('SequenceLoad', data);
        //io.to(`${socketId}`).emit('SequenceLoad', data);

     }, 1000 * 3);

  });
}

Version of socket.io in my project:

"socket.io": "^2.2.0",
"socket.io-client": "^2.2.0"

Any help would great, correct me if i'm doing wrong because i'm new to it. Thanks

How do you want to select a particular socket/client? Via its id? — Nick Parsons
– Nick Parsons, Commented Jun 19, 2019 at 7:28

James · Accepted Answer · 2019-06-19 07:37:37Z

1

Given you have the socket instance, you can send to a specific client directly by:

io.to(`${socket.id}`).emit(...);

See Emit cheatsheet

edited Jun 19, 2019 at 7:37

answered Jun 19, 2019 at 7:31

James

82.4k19 gold badges172 silver badges245 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

Harry .Naeem Over a year ago

You can see in my post that i'm already doing it but it is not working.

James Over a year ago

@Harry.Naeem that doesn't mean it's not the correct way to do this - also have you looked at my answer closely? I'm not using the ID you fetch from the array, I'm using the socket.id directly (this would be the same difference due to how closures work). I believe the issue is your loop / ID fetch isn't giving you the correct ID, try using the socket.id directly, I'd fully expect it to work.

Harry .Naeem Over a year ago

I didn't said it is wrong way but i have tried this. My loop is giving me the correct id that i have saved and i'm using logs to see the socket id before emiting the data. But anyhow i will take a look into it as well

Harry .Naeem Over a year ago

Yes i have tried this thing, but still it doesn't work

Collectives™ on Stack Overflow

How to send events/messages to specific clients in node.js using Socket.io?

1 Answer 1

4 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

4 Comments

Your Answer

Sign up or log in

Post as a guest

Related