Nginx Unit not conforming to ASGI spec on websocket connections

[FixFlare]

I'm using the "Litestar" package to host a python API using Nginx Unit.

During development I used Litestar's recommended dev server "uvicorn" and did not experience any issues until I deployed to production running Nginx Unit and then got the error "405: Method Not Allowed" when I tried to make my websocket connections.

Tracing the issue, I found that the method being sent on the websocket connection was set to "GET" and the way Litestar handles determining if it's a websocket connection is based on the method being "None" so the fact that Nginx Unit is sending "GET" for the request is breaking it.

When I check the websocket spec, page 17, point 2 it says

"The method of the request MUST be GET, and the HTTP version MUST be at least 1.1."

So I initially thought Litestar was the problem and filed an issue over there.

The Litestar maintainers advised that the ASGI spec does not include a "method" key and so it would in theory be against the ASGI spec for Nginx Unit to be sending it.

If you take a look at the ASGI specs, the websocket scope does not define a method key: https://asgi.readthedocs.io/en/latest/specs/www.html#websocket-connection-scope.

The RFC you are referring to is the initial request, which isn't handled by the ASGI app, but the ASGI server.

I have a more detailed writeup over on the Litestar github here

I also made a git repo that allows you to reproduce the problem here: https://github.com/FixFlare/bug_3887

If I can clarify anything about the repo or the issue please let me know.

Thanks,