Add *args to Middleware and improve its type hints
#2381
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Use ParamSpec to provide concrete type annotations for middleware's parameters.
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Kludex
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*args to Middleware and its type hints
Kludex
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*args to Middleware and its type hints*args to Middleware and improve its type hints
starlette/applications.py
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| def add_middleware(self, middleware_class: type, **options: typing.Any) -> None: | ||
| def add_middleware( | ||
| self, | ||
| middleware_class: typing.Type[MiddlewareClass[P]], |
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I figured that we could achieve more precise annotation via typing.Protocol. Moreover, this ensures that the middleware instance does adhere to the ASGI protocol.
starlette/middleware/__init__.py
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| P = ParamSpec("P") | ||
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| class MiddlewareClass(Protocol[P]): # pragma: no cover |
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Can we somehow make this private?
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Also why is there pragma here? Doesn't it get run just by being imported?
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This particular line - as well as the class body - does get run when imported. However, the empty body (...) of __init__ and __call__ does not, since those are not being called. Putting pragma at the top of the class was merely a shortcut - not to put pragma in both of those functions.
Though it's probably best to be explicit. Changed.
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Makes total sense! It just confused me.
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Use ParamSpec to provide concrete type annotations for middleware's parameters.
Summary
See #2380
Checklist
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.