Socket.io向特定用户发出

Question

I have two clients: Client 1 and Client 2. Client 1 sends a message to Client 2 specifically without broadcasting the message to the rest of the clients.

From Client 1:

var socket = io();

socket.on("connect", () => {  
  button.addEventListener("click", function() {
     socket.emit("send", {room, message, client1_id, client2_id});
  })
})

Client 2 sends its socket.io session id to the backend first, and awaits for the backend to emit to Client 2 specifically:

var socket = io();

socket.on("connect", () => {
  socket.emit("send_id", (socket.io.engine.id))
  socket.on(client2_id, (data) => {
    console.log(data);
  })
})

Node.js backend:

var tech = io.of("/");

tech.on("connection", (socket) => {
  var receiver_id;
  socket.on("send_id", (data) => {
    receiver_id = data;
  })
  socket.on("send", data => {
    io.to(receiver_id).emit(data.client2_id, "hello");
  })
})

There is no console.log at Client 2 at the end, if I load Client 1 and 2 both together, then click on the button.

Could somebody tells me what it is wrong here, please?

Thanks for your help.

Answer 1

When Client 1 send emit event, the event will be handle by thread of Client1.

This mean, in line io.to(receiver_id).emit(data.client2_id, "hello"); , there receiver_id is id of Client1's socket.

receiver_id variable is not necessary because you have receiver id in data .

Try use my snippet code:

io.to(data.client2_id).emit(data.client2_id, "hello"); // I think it will be better if you change event name to `direct-message` instead of `data.client2_id`