Server-side namespaced disconnect

[DanielBaulig]

As far as I can tell disconnecting from a namespace is only possible from the client side. It does not seem to be possible to disconnect a client from just a namespace from the server side.

Forced disconnection from the server is an essential feature. Multiplexing over a single connection is hampered a lot if a server can only disconnect a client from all namespaces at once. E.g. a module based on socket.io might disconnect a socket if something goes wrong badly. One couldn't pull in that module and use it on a multiplexed connection in it's own namespace without it interfering with other stuff going on on that connection.

The code for dealing with namespaced disconnects essentially is present. The protocol also specifies it. And it is already possible, from the client side.

What do you guys think?

[rauchg]

socket.disconnect should only close the transport if no other multiplexed sockets are open I think

[DanielBaulig]

I have the following setup:

io.of('/one').on('connection', function (socket) {
  socket.log.debug('socket connected to namespace one', socket.id);
  socket.disconnect();
});

io.of('/two').on('connection', function (socket) {
  socket.log.debug('socket connected to namespace two', socket.id);
});

Note, that I do not disconnect the namespace two namespaced socket. However, on the client both on('disconnect') events will fire.

PS: output of socket.io

info  - booting client
info  - transport end by forced client disconnection
debug - websocket writing 0::
info  - transport end

[rauchg]

I see. That's definitely a bug!

[DanielBaulig]

Actually, from looking at the source code it looks more like a "feature":

https://github.com/LearnBoost/socket.io/blob/master/lib/socket.js#L290
https://github.com/LearnBoost/socket.io/blob/master/lib/transport.js#L202

There doesn't seem to be any code to handle that use-case.

[rauchg]

Yep, that's definitely something we need to change =] Thanks for bringing this up

[DanielBaulig]

I played around a bit and it seems that doing the following will actually perform a graceful namespaced disconnect:

socket.packet({type: 'disconnect'});
socket.namespace.manager.onLeave(socket.id, socket.namespace.name);
socket.$emit('disconnect', 'booted');

It does not take into account what happens, if the namespace was the last namespace the client was connected to though. But as I think about it, I don't think anything special should happen when the client disconnects from the last namespace, since it will still be connected to the global namespace anyway.

Also I thin there is another bug, that is not directly related but I found while doing research on this bug: if a client disconnects from a namespace you would expect it to also leave all rooms associated with that namespace. This is not the case though. I will open up another issue and describe that more in details there.

[DanielBaulig]

The second commit fixes the problem.

[nh2]

Can this be closed?

[broject]

Yep, that's definitely something we need to change =] Thanks for bringing this up

why do not fix this problems "client namespace disconnect". i never call disconnect event normal process. but call disconnect it is very trouble to all developers.!!

[broject]

WHY This issue was closed.
WHERE IS SOLUTIONS ?????????????????????????????????

[laneschmidt]

this is still happening immediately after connecting.

here's my implementation:

// server.js
// version: "socket.io": "^2.3.0",

const express = require('express');
const http = require('http');
const cors = require('cors');
const socketIO = require('socket.io');

import { generateToken } from '../utils/helpers');

const port = 80;
const app = express().use(cors);
const server = http.Server(app);
const io = socketIO(server);

io.on('connection', (socket) => {
  console.log('Socket connected');

  const token = await generateToken();

  socket.on('ping', () => {
    io.emit('ping', 'pong');
  });

  socket.on('disconnect', (reason) => {
    console.log('Socket disconnected. Reason:', reason);
  });
});

server.listen(port, () => {
  console.log(`Server started on port ${port}`);
});

// AppComponent.tsx
// version: "socket.io-client": "^2.3.0",

import io from 'socket.io-client';

...

const socket = io(socketURL);
socket.emit('ping');
socket.on('ping', (res: any) => console.log('res', res));

i have verbose debugging enabled but can't see any errors in the console, so i can see that it connects then immediately disconnects.

the frontend logs:

browser.js:133 socket.io-client:socket server disconnect (/) +2ms
browser.js:133 socket.io-client:manager disconnect +17ms
engine.io-client:socket socket close with reason: "forced close" +2ms

the server logs: Socket disconnected. Reason: server namespace disconnect.

nothing is telling to to disconnect.