Deprecate registering synchronous web handlers

[asvetlov]

Right now aiohttp.web wraps sync handlers by async wrapper.
I think the behavior should be deprecated.

Opinions?

[kxepal]

+1

[fafhrd91]

+1

[kornsn]

Possible we have a little bug.

I have a handler that looks like a code below:

class MyHandler:
    aync def __call__(self, request):
        ...

This handler is asinchronous, but aiohttp thinks like it is sinchronous and writes deprecation warning.

Please, let's check it.

We can add one more test into test_urldispatch.py

def test_not_deprecate_async_call_class(router, recwarn):
    class Handler:
        async def __call__(self, request):
            pass
            
    router.add_route('GET', '/handler', handler)
     
    assert len(recwarn) == 0

What do you think? Should I make a pull-request?

[kornsn]

Also, using of lambda functions leads to deprecation warnings too, and we have not async lambdas. May be just let to use both of sync and async functions?

Sorry for late opinion.

[asvetlov]

Sorry, lambdas support is deprecated and will be removed.
Both sync and async makes a mess and unnecessary slowdown.

Regarding async __call__ -- I really like to solve it on Python stdlib introspection level.
Maybe async_calllable(arg) utility (we have callable(arg) already)

If you are interested in -- file a bug on https://bugs.python.org , add asvetlov and yselivanov to nosy list

[lock]

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a [new issue] for related bugs.
If you feel like there's important points made in this discussion, please include those exceprts into that [new issue].
[new issue]: https://github.com/aio-libs/aiohttp/issues/new