Node js socket.io-client 4.0.1 Error: server error

[Jonathan-Gardner]

I'm running a SocketIOSharp server trying to connect with a Node js socket.io-client 4.0.1
I'm using the example server and trying to connect with the following client:

const io = require("socket.io-client");

const socket = io.connect("http://127.0.0.1:9001/", { reconnect: true, rejectUnauthorized: false});
socket.on("connect_error", (err) => {
  console.log(err);
});

socket.on("connect", () => {
  console.log(socket.id); // "G5p5..."
});

The server says "Connected" repeatedly as the client tries to connect.
The client however throws this error:

Error: server error
    at Socket.onPacket (C:\...\test-client\node_modules\engine.io-client\lib\socket.js:401:23)
    at XHR.<anonymous> (C:\...\test-client\node_modules\engine.io-client\lib\socket.js:216:14)
    at XHR.Emitter.emit (C:\...\test-client\node_modules\component-emitter\index.js:145:20)
    at XHR.onPacket (C:\...\test-client\node_modules\engine.io-client\lib\transport.js:105:10)
    at callback (C:\...\test-client\node_modules\engine.io-client\lib\transports\polling.js:101:12)
    at Array.forEach (<anonymous>)
    at XHR.onData (C:\...\test-client\node_modules\engine.io-client\lib\transports\polling.js:105:56)
    at Request.<anonymous> (C:\...\test-client\node_modules\engine.io-client\lib\transports\polling-xhr.js:94:12)
    at Request.Emitter.emit (C:\...\test-client\node_modules\component-emitter\index.js:145:20)
    at Request.onData (C:\...\test-client\node_modules\engine.io-client\lib\transports\polling-xhr.js:236:10) { code: 'parser error' }

Edit 1:
if I set the client to use websockets for the transport by default I receive the following error instead:

Error: It seems you are trying to reach a Socket.IO server in v2.x with a v3.x client, but they are not compatible (more information here: https://socket.io/docs/v3/migrating-from-2-x-to-3-0/)
    at Socket.onpacket (C:\...\test-client\node_modules\socket.io-client\build\socket.js:210:56)
    at Manager.Emitter.emit (C:\...\test-client\node_modules\component-emitter\index.js:145:20)
    at Manager.emitReserved (C:\...\test-client\node_modules\socket.io-client\build\typed-events.js:59:15)
    at Manager.ondecoded (C:\...\test-client\node_modules\socket.io-client\build\manager.js:207:14)
    at Decoder.Emitter.emit (C:\...\test-client\node_modules\component-emitter\index.js:145:20)
    at Decoder.add (C:\...\test-client\node_modules\socket.io-parser\dist\index.js:117:23)
    at Manager.ondata (C:\...\test-client\node_modules\socket.io-client\build\manager.js:199:22)
    at Socket.Emitter.emit (C:\...\test-client\node_modules\component-emitter\index.js:145:20)
    at Socket.onPacket (C:\...\test-client\node_modules\engine.io-client\lib\socket.js:407:16)
    at WS.<anonymous> (C:\...\test-client\node_modules\engine.io-client\lib\socket.js:216:14)

Seems like the packet is missing the data content when using websockets only
{ type: 0, nsp: '/' }

Any help would be appreciated!

[npatroni]

i've the same problem, @DustedHam did you find the solution?

[Jonathan-Gardner]

Unfortunatly I did not find a solution.
I was using this for a WebRTC signalling service so I didn't need many messages.
I ended up using WebSocketSharp and rolling my own messaging system.

I think a fix may be possible, but I didn't have time to get super farmilier with the inner workings of this library.