Expose handler type?

[AustinScola]

I'm writing a middleware coroutine in a project which is type-checked with mypy. I want to annotated the handler parameter similar to the following:

@middleware
async def my_middleware(request: Request, handler: Handler) -> Response:
    ...

I can't seem to find a handler type alias to use in aiohttp though I see a few defined throughout the code (I could be mistaken that none are available to use?):

$ ack "Handler.*Callable" aiohttp
web_middlewares.py
44:_Handler = Callable[[Request], Awaitable[StreamResponse]]

web_protocol.py
61:_RequestHandler = Callable[[BaseRequest], Awaitable[StreamResponse]]

web_urldispatcher.py
84:_WebHandler = Callable[[Request], Awaitable[StreamResponse]]
85:_ExpectHandler = Callable[[Request], Awaitable[None]]

web_app.py
51:    _Handler = Callable[[Request], Awaitable[StreamResponse]]
60:    _Handler = Callable

web_routedef.py
55:_SimpleHandler = Callable[[Request], Awaitable[StreamResponse]]

Maybe one should be added to aiohttp.typdefs?

P.S. Happy to contribute!

[Dreamsorcerer]

Duplicate #4686

I think it's probably time for someone to try this out in a PR, then we can discuss it there.

[AustinScola]

Made PR #5847