Handle case when websocket client disconnects before websocket connection is accepted

[invisibleroads]

Please see the relevant "discussion" https://github.com/encode/uvicorn/discussions/2311

[Kludex]

We need a test for this.

Also, I think we can check if the transport is closing instead: if self.transport.is_closing().

[Kludex]

@invisibleroads Are you still interested in working on this?

[invisibleroads]

Hi Marcelo, I was travelling. Let me look at the test.

Would you prefer the is closing check? I feel the try catch would be safer because it is more general.

On Wed, Apr 24, 2024, 6:39 AM Marcelo Trylesinski @.***> wrote:

@invisibleroads https://github.com/invisibleroads Are you still interested in working on this?

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[Kludex]

Hi Marcelo, I was travelling. Let me look at the test. Would you prefer the is closing check? I feel the try catch would be safer because it is more general. … On Wed, Apr 24, 2024, 6:39 AM Marcelo Trylesinski @.> wrote: @invisibleroads https://github.com/invisibleroads Are you still interested in working on this? — Reply to this email directly, view it on GitHub <#2312 (comment)>, or unsubscribe https://github.com/notifications/unsubscribe-auth/AACBDLAPIHWKGEFZX4B2SWDY66DWDAVCNFSM6AAAAABGQ6JJDCVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDANZUGY2DONRUGI . You are receiving this because you were mentioned.Message ID: @.>

Yes, that's what I said on my last message.

We also need a test here.

[invisibleroads]

@Kludex I tried to recreate the situation where the transport is closed when the server tries to send the 500 error, but I can't get the situation to recreate exactly and don't think mocking would work either.

async def test_asgi_shutdown_before_handshake(ws_protocol_cls: WSProtocol, http_protocol_cls: HTTPProtocol, unused_tcp_port: int):
    """
    """
    async def app(scope: Scope, receive: ASGIReceiveCallable, send: ASGISendCallable):
        # await asyncio.sleep(2)
        # server = d['server']
        list(server.server_state.connections)[0].transport.close()
        # server.should_exit = True
        # server.force_exit = True
        await asyncio.sleep(2)

    config = Config(
        app=app,
        ws=ws_protocol_cls,
        http=http_protocol_cls,
        lifespan="off",
        port=unused_tcp_port,
    )
    async with run_server(config) as server:
        async with websockets.client.connect(f"ws://127.0.0.1:{unused_tcp_port}"):
            pass
        # try:
            # async with websockets.client.connect(f"ws://127.0.0.1:{unused_tcp_port}", open_timeout=1):
                # pass
        # except:
            # pass
        # await asyncio.sleep(3)

INFO:     Started server process [37557]
INFO:     Uvicorn running on http://127.0.0.1:55877 (Press CTRL+C to quit)
INFO:     Shutting down
INFO:     Waiting for background tasks to complete. (CTRL+C to force quit)
ERROR:    ASGI callable returned without sending handshake.
INFO:     connection closed
--------------------------------------------------------------- Captured log call ----------------------------------------------------------------
INFO     uvicorn.error:server.py:82 Started server process [37557]
INFO     uvicorn.error:server.py:214 Uvicorn running on http://127.0.0.1:55877 (Press CTRL+C to quit)
INFO     uvicorn.error:server.py:258 Shutting down
INFO     uvicorn.error:server.py:303 Waiting for background tasks to complete. (CTRL+C to force quit)
ERROR    uvicorn.error:websockets_impl.py:257 ASGI callable returned without sending handshake.
INFO     uvicorn.error:server.py:264 connection closed

Whatever I do, the connection keeps closing only after sending the 500 error in the test.

[invisibleroads]

Updated the commit to check if transport.is_closing

[invisibleroads]

We can talk about this at the PyCon sprints on Monday if you're going to be there.

[Kludex]

I'll be there on the 16 👀

[Kludex]

More fixes are needed... The connection_lost on WS implementation has a logical issue.

[Kludex]

I need to fix this PR, sorry.

[invisibleroads]

You know more about the edge cases than I do. I wish I could help more here, but you are welcome to modify the pull request as much as is needed

[Kludex]

This is an issue with uvloop. I've written an MRE on their side: https://github.com/MagicStack/uvloop/issues/506#issuecomment-2404171195

[Kludex]

Since this is a uvloop issue, I'll be closing this.