[FEATURE] Headers should be typed as Optional

Is your feature request related to a problem? Please describe. Setting headers for routes requires adding invalid type information because while headers are optional, they cannot be typed as optional.

Describe the solution you’d like Headers that are typed as str should error if they are not provided. Otherwise, headers should be typed as Optional if they are so.

Describe alternatives you’ve considered N/A

Additional context

x_custom_header will not be str if the request doesn’t include it.

async def example_route(
    payload: dict, *, x_custom_header: str = Header(None)
):
    assert x_custom_header is not None
    return {"msg": "ok"}

Changing the type hint to typing.Optional[str] raises an assertion error: AssertionError('Parameters for Query and Header must be of type str, int, float, bool, list, tuple or set...

[Pycz]

@ElPapi42 just use param_name: str = Header(...)

For everyone confused as me ... here is ellipsis operator - I mean, literally ... Or you can as well do this:

from pydantic import Required

param_name: str = Header(Required)

(in pydentic Required = Ellipsis)

[ycd]

@ElPapi42 just use param_name: str = Header(...)