Allow parameter and return types of route handler delegates (API Controllers) to contribute to endpoint metadata

[brunolins16]

Is there an existing issue for this?

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Is your feature request related to a problem? Please describe the problem.

Introduce the capability for types used for parameters and return values for API controller actions to contribute to metadata of the endpoint they're mapped to. This will allow types that implement custom binding logic via TryParse and IResult types, to add metadata that describes the API parameters and responses in Swagger UI and OpenAPI documents.

This is an idea of feature parity with Minimal API, after #40646.

Describe the solution you'd like

We should introduce the same support for the new interfaces, IEndpointParameterMetadataProvider and IEndpointMetadataProvider that currently is implemented in Minimal Actions.

Additional context

No response

[ghost]

Thanks for contacting us.

We're moving this issue to the .NET 7 Planning milestone for future evaluation / consideration. We would like to keep this around to collect more feedback, which can help us with prioritizing this work. We will re-evaluate this issue, during our next planning meeting(s).
If we later determine, that the issue has no community involvement, or it's very rare and low-impact issue, we will close it - so that the team can focus on more important and high impact issues.
To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.

[captainsafia]

Triage: Bruno proposes implementing this as an ApiConvention.

We also discussed whether this would worthwhile to do if MVC does not support BindAsync and concluded there is value in this work even though MVC doesn't support BindAsync as of writing.