feat: support anyio, sending denial response, handshake headers

[WSH032]

Summary

Added

• support asyncio and Trio through AnyIO
• support sending websocket denial response
• support sending headers during websocket handshake
• add tests for hypercorn server

Changed

• remove path parameter in proxy method
• the return signature of ReverseWebSocketProxy.proxy has been changed;
  it no longer returns StarletteResponse, but instead returns True

Test

• fix the warnings in the tests by not using deprecated APIs from httpx

Checklist

• I've read CONTRIBUTING.md.
• I understand that this PR may be closed in case there was no previous discussion. (This doesn't apply to typos!)
• I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• I've updated the documentation accordingly.

[codecov]

Codecov Report

Attention: Patch coverage is 85.41667% with 14 lines in your changes are missing coverage. Please review.

Project coverage is 96.39%. Comparing base (977d9c1) to head (3d2b0ea).

Files	Patch %	Lines
src/fastapi_proxy_lib/core/websocket.py	84.09%	10 Missing and 4 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #34      +/-   ##
==========================================
- Coverage   96.74%   96.39%   -0.35%     
==========================================
  Files           9        9              
  Lines         461      472      +11     
  Branches       67       73       +6     
==========================================
+ Hits          446      455       +9     
- Misses          9       11       +2     
  Partials        6        6              

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[WSH032]

The test succeeded on Windows but failed on Linux, preventing us from merging. Unfortunately, I don't have time to address this issue at the moment. If someone is willing to pick it up, I can provide guidance.

Need Improvement

• Revert: feat!: remove path parameter in proxy method
  The downstream is already passing this parameter. Let's issue a deprecation warning in this version and remove it in the next version.
• Revert: the return signature of ReverseWebSocketProxy.proxy has been changed in this commit
  Let's keep the original signature so users can handle responses themselves; we should provide a helper method to assist users in sending denial responses rather than sending responses ourselves.

TODO

• Use ... to represent default parameters instead of importing these private variables from httpx-ws

  fastapi-proxy-lib/src/fastapi_proxy_lib/core/websocket.py

  Lines 39 to 44 in 3d2b0ea

  	from httpx_ws._api import (
  	DEFAULT_KEEPALIVE_PING_INTERVAL_SECONDS,
  	DEFAULT_KEEPALIVE_PING_TIMEOUT_SECONDS,
  	DEFAULT_MAX_MESSAGE_SIZE_BYTES,
  	DEFAULT_QUEUE_SIZE,
  	)

• Fix: can not receive the websocket close reason

  fastapi-proxy-lib/tests/test_ws.py

  Lines 212 to 215 in 3d2b0ea

  	assert exce.value.code == code
  	# XXX, HACK, TODO:
  	# reaseon are wrong, httpx-ws can't send close reason correctly
  	# assert exce.value.reason == reason

  
  This is an upstream issue of ASGI, and we are unable to address it. We will track it here
  Can't send close reason correctly frankie567/httpx-ws#70.

• Fix: unable to read the content of WebSocketUpgradeError.response

  fastapi-proxy-lib/src/fastapi_proxy_lib/core/websocket.py

  Lines 440 to 442 in 3d2b0ea

  	# # XXX: Unable to read the content of WebSocketUpgradeError.response
  	# # See: https://github.com/frankie567/httpx-ws/discussions/69
  	# content = await proxy_res.aread()

  
  This is an upstream issue of httpx-ws, We will track it here
  Unable to read the content of `WebSocketUpgradeError.response` frankie567/httpx-ws#69

• Use StreamingResponse in favor of Response

  fastapi-proxy-lib/src/fastapi_proxy_lib/core/websocket.py

  Lines 431 to 438 in 3d2b0ea

  	# # XXX: Can not use send_denial_response with StreamingResponse
  	# # See: https://github.com/encode/starlette/discussions/2566
  	# denial_response = StreamingResponse(
  	# content=proxy_res.aiter_raw(),
  	# status_code=proxy_res.status_code,
  	# headers=proxy_res.headers,
  	# background=background,
  	# )

  
  This is an upstream issue of starlette, We will track it here
  Can not use `send_denial_response` with `StreamingResponse` encode/starlette#2566

[WSH032]

I am aware of such downstream use cases, so we cannot deprecate the path parameter, which can allow us to add a dynamic path prefix.