Replace BaseHTTPMiddleware with pure ASGI middleware

[adriangb]

Hi, I am a Starlette dev. We are trying to discourage usage of BaseHTTPMiddleware.

[HassanAbouelela]

Hello, thanks for your contribution. I'll try to get to it this week, but would you mind fixing the linting errors in the meantime? Thanks!

[adriangb]

done

[HassanAbouelela]

Hey I'm working on reviewing this right now, is there any reference for why we're moving away from this? I'm going through the documentation and I can't see anything on it or the recommended approach.

[HassanAbouelela]

Alright, I see the issue you linked, I'll track there

[adriangb]

Please check out the warnings in this section of the docs: https://www.starlette.io/middleware/#basehttpmiddleware

BaseHTTPMiddleware has bugs that we don't think can be fixed. We may deprecate it in the future (although that's not finalized), but as a first step we want to discourage its usage especially in libraries.

[HassanAbouelela]

This project isn't a library, but we're happy to help where we can 👍.

[HassanAbouelela]

Everything looks fine, thanks for your contribution. Is there an ETA on when the docs will be updated? It's really difficult to deal with this as is.

[adriangb]

What part of the docs are giving you trouble / would you like updated?

[HassanAbouelela]

The largest issue right now is that they aren't merged, so no one will know where to look for them. This is only a temporary problem of course, but if you plan on making this same migration on projects where they need to edit the middleware more frequently, that can be a blocker.

More relevantly, there are a few minor things here and there. In no particular order:

• The Reusing Starlette components section feels lacking. It explains how to go about creating a request and response object in the __call__, but does not explain how that will relate to the request and response within your actual codebase. For instance, I would never have gotten the trick you used for setting our request scope from what's written there.
• This is related to the previous point, but the Per-request state confused me for a while. I assumed that's what I was looking for since it had all the right keywords, and I believed at first that the docs were saying we shouldn't do it anymore. Particularly, calling it request lead me to believe that it's about setting the scope on the request object, instead of the middleware class.