add response headers to scope

[mindrunner]

While implementing a custom logger formatter to support gunicorn logging syntax (https://docs.gunicorn.org/en/stable/settings.html#logging), we had some crucial information missing. One of which, we could solve by injecting the response headers to the scope object. This might be a first step towards
#527

[marco-loche-work]

Please merge it!!!!

[euri10]

I don't think the spec has that scope key, am I missing something ?

[mindrunner]

For me it worked in the specific context I had to use it. However, I am not really into the gunicon/uvicorn code, so I am not entirely sure about the consequences of this change.

[florimondmanca]

Hello!

I don't think the spec has that scope key, am I missing something ?

Yup, the ASGI spec doesn't define putting response headers into the scope. If that's something you'd be ready to champion in the ASGI repo, then please feel free to. But until then I'd advise us against implementing ASGI-level behavior into Uvicorn that's not defined in the spec — otherwise we break the purpose of ASGI as a standard that enables interoperability between apps and servers. 😕

I'll close this for now, not to say that the original use case isn't appropriate for discussion, but I don't think this is the way we'll be going forward with. If there's any specific use case you can expose for discussion then we can still try and find an alternative solution. :-)