connection

[mhrezanezhad]

Hello and greetings,

How are you doing? I was wondering if you could help me connect to a signal socket using Python. I would greatly appreciate your guidance on this matter.

[mhrezanezhad]

I forgot to mention that the version I am using is 5

[gfoidl]

Do you mean SignalR?
Then https://github.com/mandrewcito/signalrcore looks promising (note: I didn't use that library myself)

Or do you mean (plain) WebSockets?
As these conform the standard, the according Python-lib should work.

Please clarify, so we can provide more concrete help.
Also note that the repo here is for development for ASP.NET Core, so may visit something like https://stackoverflow.com/ or similar to get help too.

[mhrezanezhad]

I have written some code to connect to a SignalR hub using the asyncio and websockets libraries. The code sets up a WebSocket connection and sends a SignalR handshake message to establish the connection. It then listens for incoming messages from the hub and periodically sends ping messages to keep the connection alive.

However, sometimes I receive the following error message: {"type":7,"error":"Connection closed with an error.","allowReconnect":true}. I did not see this error happen in my browser, and the browser is just pinging like my code.

How can I make the connection more stable? Are there any mistakes in my code that could be causing this issue?

async def connectToHub(url, str_connection_id):
    def toSignalRMessage(data):
        return f'{json.dumps(data)}\u001e'

    uri = url + str_connection_id
    async with  websockets.connect(uri, extra_headers=headers) as websocket:
        async def startPinging():
            while _running:
                await asyncio.sleep(10)
                await websocket.send(toSignalRMessage({"type": 6}))

        async def handShake():
            await websocket.send(toSignalRMessage({"protocol": "json", "version": 1}))
            handShake_resp = await websocket.recv()
            print(handShake_resp)

        async def listen():
            while _running:
                resp = await websocket.recv()
                print(resp)

        await handShake()
        _running = True
        listen_task = asyncio.create_task(listen())
        ping_task = asyncio.create_task(startPinging())

        await ping_task
        await listen_task


asyncio.run(connectToHub("wss://notif.ibtrader.ir/message-hub?id=", self.message_hub_connection_token))

[engineering87]

Hello, here some tips you should try:

Handling reconnections:
Implement logic to handle reconnections when the connection drops. You should implement a reconnect strategy like this:

async def reconnect():
    attempts = 0
    while attempts < max_retries and not _running:
        attempts += 1
        try:
            await connectToHub(url, str_connection_id)
            break
        except Exception as e:
            print(f"Reconnect attempt {attempts} failed: {e}")
            await asyncio.sleep(retry_delay)

Ping time
Ensure that your ping interval aligns with the server's expectations. Also, ensure that pings are being sent before the connection times out.

Error handling
Add error handling to manage potential disconnections or other WebSocket errors gracefully.

async def listen():
    while _running:
        try:
            resp = await websocket.recv()
            print(resp)
        except websockets.exceptions.ConnectionClosedError as e:
            print(f"Connection closed with error: {e}")
            _running = False
        except Exception as e:
            print(f"Unexpected error: {e}")
            _running = False

Lastly, ensure that the WebSocket connection is properly closed when _running is set to False.