Provide the un-%-decoded path

As far as I can tell, ASGI follows the precedent set by WSGI in providing only a %-decoded string representation of the path. I believe this is a mistake. In particular, %2F is not a path separator by the URI RFC, but an application can’t tell it apart from /.

I suggest either providing a raw_path byte string, or deserializing the path properly and passing it as a list.

[CounterPillow]

I see the issue with downstream proxies since the website developers have no influence over these, but at least with reverse-proxies one could name the ones that do violate the RFC in this way in the documentation for such a raw_path string or alternative interface.

Right now ASGI is in the unfortunate position of throwing away information because servers further up the HTTP hot potato game would break assumptions made by devs about the validity of this information. This is very painful if a developer has confirmed their assumptions in the deployment they run, and determined that ASGI is the only place this information is being discarded.

[davidism]

An optional raw_path was added to the spec here: https://github.com/django/asgiref/pull/92

@andrewgodwin can you lock this? I don’t think there’s any more to be said here. If something new comes up, it can be discussed as a new issue.