feat: expose FluentValidation rules in API definitions

[nazem0]

Description

Resolves #26083

Adds an extension point for contributing property metadata during API description model generation and provides a FluentValidation implementation.

Changes:

• Added IPropertyApiDescriptionModelContributor to Volo.Abp.Http.Modeling.
• Updated AspNetCoreApiDescriptionModelProvider to resolve and execute registered property API description model contributors.
• Added FluentValidationApiDescriptionModelContributor.
• Registered the FluentValidation contributor with dependency injection.
• FluentValidation rules can now contribute validation metadata to API description properties.

This is not a breaking change.

Checklist

• I fully tested it as developer / designer and created unit / integration tests
• I documented it (or no need to document or I will create a separate documentation issue)

How to test it?

1. Create a DTO with a FluentValidation validator.
2. Define validation rules for its properties.
3. Register the validator normally with FluentValidation.
4. Generate the ABP API definition using /api/abp/api-definition.
5. Verify that the corresponding property API description contains the validation metadata contributed by the FluentValidation contributor.

[nazem0]

@maliming This PR addresses #26083. Would appreciate your feedback on the approach when you have a chance.

[maliming]

Hi,

Thanks for the PR. I pushed some changes to your branch:

• The implementation moved to a new Volo.Abp.Http.FluentValidation package, so Volo.Abp.FluentValidation does not depend on Volo.Abp.Http.
• The contributor takes a context and is async now, like the other contributors in the framework.
• Only the rules that apply to every instance are published. A When(...) block keeps its condition on the rule instead of the components, and a named rule set never runs with the default selector.
• GreaterThan and ExclusiveBetween needed the new MinimumIsExclusive / MaximumIsExclusive flags, otherwise the client would accept a boundary value the server rejects.

There is a test project and a documentation section listing what the mapping can not express.

Please take a look.

Thanks

[nazem0]

Hi @maliming,

Thanks for improving the implementation and adding the tests and documentation.

• Making a new project, Volo.Abp.Http.FluentValidation, was the most suitable approach.
• Making the contributor async also makes sense, since we don't know what future contributor implementations might need to do, and this covers any async operations they may require. ✅
• GreaterThan and ExclusiveBetween — I think I missed that part during the implementation 😐, Thanks for adding it 😅