Getting TypeError: on_connect() missing 1 required positional argument: 'path'. V1.6 ocpp

[josalvmo]

hi, I am getting this error when testing example code located on this repo for V1.6 (ocpp/examples
/v16/)

Any ideas how to fix?

INFO:websockets.server:server listening on 0.0.0.0:9000
INFO:root:Server Started listening to new connections...
INFO:websockets.server:connection open
ERROR:websockets.server:connection handler failed
Traceback (most recent call last):
File ".venv\Lib\site-packages\websockets\asyncio\server.py", line 374, in conn_handler
await self.handler(connection)
^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: on_connect() missing 1 required positional argument: 'path'
Traceback (most recent call last):
File "C:\Program Files\Python311\Lib\asyncio\runners.py", line 118, in run
return self._loop.run_until_complete(task)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Program Files\Python311\Lib\asyncio\base_events.py", line 653, in run_until_complete
return future.result()
^^^^^^^^^^^^^^^
File "c:\Repos\raspberry-pi\ocpp\ocpp_v16\ocpp_server1\central_system.py", line 71, in main
await server.wait_closed()
File ".venv\Lib\site-packages\websockets\asyncio\server.py", line 492, in wait_closed
await asyncio.shield(self.closed_waiter)
asyncio.exceptions.CancelledError

[a-alak]

Can you show the code you wrote?

[josalvmo]

Can you show the code you wrote?

Is the same exact code of examples folder.

https://github.com/mobilityhouse/ocpp/tree/master/examples/v16

Ran central_system.py and charge_point.py on same system

Only had to change BootNotificationPayload to BootNotification on charge_point.py

[a-alak]

The path argument to the connection handler is deprecated in the websockets library, so if you are using a later version, you should get the path as an attribute from the connection instead (see here).
This is a version that will work with later versions of websockets lib:

async def on_connect(websocket):
    """For every new charge point that connects, create a ChargePoint
    instance and start listening for messages.
    """
    try:
        requested_protocols = websocket.request_headers["Sec-WebSocket-Protocol"]
    except KeyError:
        logging.error("Client hasn't requested any Subprotocol. Closing Connection")
        return await websocket.close()
    if websocket.subprotocol:
        logging.info("Protocols Matched: %s", websocket.subprotocol)
    else:
        # In the websockets lib if no subprotocols are supported by the
        # client and the server, it proceeds without a subprotocol,
        # so we have to manually close the connection.
        logging.warning(
            "Protocols Mismatched | Expected Subprotocols: %s,"
            " but client supports  %s | Closing connection",
            websocket.available_subprotocols,
            requested_protocols,
        )
        return await websocket.close()

    charge_point_id = websocket.path.strip("/")
    cp = ChargePoint(charge_point_id, websocket)

    await cp.start()

There has actually been a lot of changes in the websockets library, so there might be other changes on the connection object. On my implementation I have not upgraded websockets yet, because I haven't had time to look through the changes.

[josalvmo]

Thanks!! I had to do another adjustments when checking headers.

Here working code:

async def on_connect(websocket: ServerConnection):
    """For every new charge point that connects, create a ChargePoint
    instance and start listening for messages.
    """
    try:
        requested_protocols = websocket.request.headers["Sec-WebSocket-Protocol"]
    except KeyError:
        logging.error("Client hasn't requested any Subprotocol. Closing Connection")
        return await websocket.close()
    
    if websocket.subprotocol:
        logging.info("Protocols Matched: %s", websocket.subprotocol)
    else:
        # In the websockets lib if no subprotocols are supported by the
        # client and the server, it proceeds without a subprotocol,
        # so we have to manually close the connection.
        logging.warning(
            "Protocols Mismatched | Expected Subprotocols: %s,"
            " but client supports  %s | Closing connection",
            websocket.available_subprotocols,
            requested_protocols,
        )
        return await websocket.close()

    charge_point_id = websocket.request.path.strip("/")
    cp = ChargePoint(charge_point_id, websocket)

    await cp.start()