reactpy.run and configure(...) refactoring

[Archmonger]

Issues

Right now reactpy.run can fail in fairly unpredictable ways which give little in terms of stack traces.

Summary

This refactors the reactpy.run call stack in order allow failures that are user-readable.

• Change reactpy.backends.utils.find_all_implementations() to first try to import <backend_name> before importing reactpy.backend.<backend_name>
  • Allows for missing sub-dependencies to not cause reactpy.run to silently fail
• Import uvicorn directly within serve_with_uvicorn in order to defer import.
  • Allows for ModuleNotFound: Could not import uvicorn exception to tell the user what went wrong
• Added CommonOptions.serve_index_route: bool
  • Allows us to not clutter the route patterns when it's not needed
  • There are real circumstances where a user might want the index route to 404
• Fix bug where in-use ports are being assigned on Windows.
  • Removes allow_reuse_waiting_ports parameter on find_available_port()
• Rename BackendImplementation to BackendProtocol
• Change load order of SUPPORTED_PACKAGES so that FastAPI has a chance to run before starlette
• Rename SUPPORTED_PACKAGES to SUPPORTED_BACKENDS
• Refactor reactpy.backend.* code to be more human readable
• Use f-strings where possible
• Merge if statements where possible
• Use contextlib.supress where possible
• Remove defunct requirements.txt file

Checklist

• Tests have been included for all bug fixes or added functionality.
• The changelog.rst has been updated with any significant changes.

[Archmonger]

@rmorshea npm install -g npm@8.5.0 seems to have broken in the github workflow in the last 24 hours. Not sure why, but I tried bumping actions/setup-node version. Did not fix it.

[rmorshea]

I was planning on doing a 1.0.1 release tomorrow. Should this wait for the next release?

[Archmonger]

Yes, technically this release has an API change (BackendImplementation to BackendProtocol), so we shouldn't put this in a hotfix release.

[Archmonger]

I discovered that our flask backend doesn't work with uvicorn due to WsgiToAsgi not allowing non-HTTP scopes. When removing this restriction, this showed that flask-sock relies on via non-standard WSGI extensions which WsgiToAsgi does not support.

I attempted to rewrite WsgiToAsgi locally but it broke a ton of other stuff.

Ref: miguelgrinberg/flask-sock#58

[rmorshea]

Generally just minor things to correct.

[Archmonger]

@rmorshea This seems to be mergeable, but needs approval.