Version not Compatible for flutter socket_io_client: ^2.0.3+1 with python-socketio==4.6.0 and python-engineio==3.13.2

[hetvaghasia39]

Issue Description:

I'm encountering compatibility issues between the Python SocketIO server and the Flutter SocketIO client. Currently, I'm using python-socketio==4.6.0 and python-engineio==3.13.2 on the server side along with flutter_socket_io: ^2.0.3+1 on the Flutter client side. While the server successfully receives events emitted by the Flutter client, the client fails to receive events emitted by the server.

Troubleshooting Steps:

To address this, I've attempted to resolve the compatibility by experimenting with different versions of Python SocketIO and Python EngineIO. Specifically, I've tested python-socketio==5.1.0 and python-engineio==4.0.0. However, with these versions, the server is unable to receive events emitted by the client, although the client should receive events emitted by the SocketIO server.

Server Configuration:

I've experimented with both ASGI and WSGI servers, including Daphne for ASGI server configuration.

Code References:

To provide further context, here are snippets of relevant code:

asgi.py file

import os
import socketio
from django.core.asgi import get_asgi_application
from apps.talks.consumers import sio

os.environ.setdefault("DJANGO_SETTINGS_MODULE", "infinity_talks.settings")

asgi_application = get_asgi_application()

application = socketio.ASGIApp(sio, other_asgi_app=asgi_application)

consumer.py file

from datetime import datetime

import socketio
from asgiref.sync import sync_to_async

sio = socketio.AsyncServer(async_mode="asgi", cors_allowed_origins="*")

background_task_started = False


@sio.event
async def connect(sid, environ):
    try:
        print(f"WebSocket connected: {sid}")
        await sio.emit("connect")
    except Exception as e:
        print(f"Error in connect event: {e}")


@sio.event
async def disconnect(sid):
    print(f"WebSocket disconnected: {sid}")


@sio.event
async def joinChat(sid, data):
    """event for both customer and listener and joining the room"""
    try:
        print("joinChat event")
        customer_id = data.get("user_id")
        listener_id = data.get("listener_id")
        from apps.admin_panel.models import ChatRoom, User

        room = await sync_to_async(ChatRoom.objects.filter)(
            customer_id=customer_id, listener_id=listener_id
        )
        room = await sync_to_async(room.first)()

        if room:
            pass
        else:
            customer = await sync_to_async(User.objects.filter)(id=customer_id)
            customer = await sync_to_async(customer.first)()
            listener = await sync_to_async(User.objects.filter)(id=listener_id)
            listener = await sync_to_async(listener.first)()
            room = await sync_to_async(ChatRoom.objects.create)(
                customer_id=customer, listener_id=listener
            )

        await sio.enter_room(sid=sid, room=room.id)
        await sio.emit(
            "onJoinChatRequest",
            data={"status": True, "message": "success", "data": {"room": room.id}},
        )
    except Exception as e:
        print("e: ", e)

Conclusion:

It's evident that there's a discrepancy in compatibility between the Python SocketIO server and the Flutter SocketIO client. Despite trying different versions of the Python packages and server configurations, the issue persists. While the server successfully receives events from the Flutter client, the reverse communication is ineffective.

Based on the testing results, it's found that:

For the Python SocketIO server to successfully receive events from the Flutter client, the minimum requirement is python-engineio==3.13.2.
Conversely, for the Flutter client to effectively receive events from the Python SocketIO server, it necessitates python-socketio==5.1.0, which in turn requires python-engineio==4.0.0.

Action Required:

I seek guidance on how to resolve this compatibility issue between the Python SocketIO server and the Flutter SocketIO client. Any insights or recommendations on configurations, version compatibility, or potential workarounds would be greatly appreciated.

Additional Version Testing:
In addition to the previously mentioned versions (python-socketio==4.6.0 and python-engineio==3.13.2, and python-socketio==5.1.0 and python-engineio==4.0.0), I have also experimented with alternative versions:

Version Combination:
python-socketio==5.1.0
python-engineio==4.0.0

Test Outcome:
With this version combination, the server was unable to receive events emitted by the client, while the client could receive events emitted by the SocketIO server.

[miguelgrinberg]

Have you asked the maintainers of the Flutter package? My goal is to offer compatibility with the reference implementations in JavaScript, I do not test other implementations.

A log session would help me determine what's going on more clearly, by the way. A verbal description of what works and what doesn't is not as clear to me.

Also, looking at their docs, their version 2.x clients are compatible with versions 3.x and 4.x of the JavaScript reference implementation, so you should use the latest 5.x python-socketio and the latest 4.x python-engineio for a comparable version of the Socket.IO protocol. Older versions are not expected to work, so do not waste time with those.

[hetvaghasia39]

Also used python-socketio==5.1.0 and python-enginio==4.0.0, still python socketio server not receiving events emitted by flutter client. I think its issue from flutter client and problem is there is only one package available for flutter that is socket io client github repo

[miguelgrinberg]

As I said above, please provide logs. A high-level description of what doesn't work isn't very useful for me to diagnose the problem. Also please use latest versions of the package, no point in testing earlier versions.