usage with Socket.io

[pi0]

Describe the change

Discussion from sveltejs/kit#1491 (comment)

socket.io has an example(ish) about integrating with crossws (which only works within node.js + depending on _internal)

Made this issue also to think how better we can deal with this kind of integration...

We could have an integrations page in docs to list other integrations like y-crossws (there could be also socketio-crossws community package to at least have better internal conditional checks)

URLs

No response

Additional information

• Would you be willing to help?

[nerg4l]

I will share my attempt. Again, sorry if this is off-topic. With the code below, I could trigger the connect (Socket.IO connected) but not the message (Socket.IO message) event. If I add message crossws hook, I can see that the server receives the event but not Socket.IO.

At the moment I just want to better understand how engine.io works and how it can be integrated with crossws.

import { createServer } from "node:http";
import crossws from "crossws/adapters/node";
import { Server as Engine } from "engine.io";
import { Server } from "socket.io";
import * as url from "node:url";

const engine = new Engine();
const io = new Server();

io.bind(engine);

io.on("connection", (socket) => {
  console.log(`Socket.IO connected: ${socket.id}`);

  socket.on("message", (data) => {
    console.log(`Socket.IO message: ${data}`);
  })

  socket.on("error", (err) => {
    console.log(`Socket.IO error: ${err}`);
  })

  socket.on("disconnect", () => {
    console.log(`Socket.IO disconnected`);
  })
});

const ws = crossws({
  hooks: {
    open(peer) {
      // @ts-expect-error private method and property
      engine.prepare(peer._internal.nodeReq);
      // @ts-expect-error private method and property
      engine.onWebSocket(peer._internal.nodeReq, peer._internal.nodeReq.socket, peer.websocket);
    }
  },
});

const server = createServer().listen(3000);

server.on("request", (req, res) => {
  const u = url.parse(req.url, true);
  if (u.pathname === "/socket.io/") {
    engine.handleRequest(req, res);
    return
  }
  if (u.pathname === "/") {
    res.end(
      `<script src="https://cdn.socket.io/4.8.1/socket.io.min.js" integrity="sha384-mkQ3/7FUtcGyoppY6bz/PORYoGqOl7/aSUMn2ymDOJcapfS6PHqxhRTMh1RR0Q6+" crossorigin="anonymous"></script>
<script>
    const socket = io('http://127.0.0.1:3000');
    socket.on('connect', () => {
      socket.emit('hello from client');
    });
</script>`,
    );
    return;
  }
  res.statusCode = 404;
  res.end(``)
})

server.on("upgrade", (req, socket, head) => {
  if (req.headers.upgrade === "websocket") {
    ws.handleUpgrade(req, socket, head);
  }
});