OpenApi won't Contains those Controllers If the Controller not starts with [ApiController] Attribute

[yangbocheng]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

Simply create a newest NET 9 aspnetcore webapi, then add Microsoft.AspNetCore.OpenApi and Scalar.AspNetCore. Then add a new Controller without [ApiController], this contoller's actions won't be included in openapi json

Expected Behavior

Controllers without [ApiController] should be included in openapi json

Steps To Reproduce

No response

Exceptions (if any)

No response

.NET Version

NET 9

Anything else?

No response

[yangbocheng]

The reason to not use the [ApiController] is : Need manual validate some form fields, or api parameters in Project
OpenApi won't Contains those Controllers If the Controller not starts with [ApiController] Attribute

<ItemGroup>
  <PackageReference Include="Microsoft.AspNetCore.OpenApi" Version="9.0.0" />
  <PackageReference Include="Scalar.AspNetCore" Version="1.2.36" />
</ItemGroup>

so if remove the [ApiController] from Test1Controller.cs , then this won't show in openapi/v1.json

[jaceks2106]

Try to use Controller instead of ControllerBase as a base class.

Update:
If you want to apply custom validation on request parameters (query, form, header, whatever), then you should apply them as nullable. Then they won't be validated by OpenAPI. Then you can apply any custom validation you want in controller method.

[yangbocheng]

I have tested again with the base : Controller and ControllerBase. They both don't work.
It seems that the only way to make openapi works well is to add [ApiController]

[captainsafia]

@yangbocheng Thanks for filing this issue!

This is a known limitation of the ApiExplorer infrastructure, the intermediary layer in ASP.NET Core that provides information about registered implementors to OpenAPI tools.

In this particular case, only controllers that are attributed with [ApiController] are automatically documented by ASP.NET Core's infrastructure.

Building on top of @jaceks2106's guidance, why are you avoiding the attribution? There maybe other ways to customize the model binding/validation behavior to your desires.

[dotnet-policy-service]

This issue has been resolved and has not had any activity for 1 day. It will be closed for housekeeping purposes.

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[yangbocheng]

Because [ApiController] will auto do things which i don't need.
So always i avoid to use it in project.

Follow Microsoft->means use the newest openapi-> means add [ApiController] to every controller-> so why not add this attribute to controller default? -> make bugs for multi programs who don't use apicontroller
Why it must add this limitation, it's very strange.

By the way, when I use the old Swagger, i don't need to add this attribute, everything work well.