Update exception handler signature to reflect HTTPConnection

[aminalaee]

Right now the docs and examples show the following signature for handlers:

async def not_found(request: Request, exc):
    return Response(content=HTML_404_PAGE, status_code=exc.status_code)

Even though this should be possible too:

async def handler(conn: HTTPConnection, exc):
    return Response(content=HTML_404_PAGE, status_code=exc.status_code)

Still in progress to find all occurrences that should be update.

[aminalaee]

I was expecting that the ExceptionMiddleware should reflect this too, but I think because of this line the WebSocket exceptions are not processed?

starlette/starlette/exceptions.py

Lines 64 to 68 in 2b54f42

	async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
	if scope["type"] != "http":
	await self.app(scope, receive, send)
	return

[adriangb]

What is the point of accepting an HTTPConnection? Error handlers don't work with WebSockets (unless #527 or similar gets merged), so in practice it's always going to be a Request, which is an HTTPConnection with additional info, right?

[aminalaee]

Error handlers don't work with WebSockets

Well I know they don't work. That's exactly what my last comment is pointing to. I didn't see @Kludex had taken the lead on that in #1263