IProblemDetailsService.WriteAsync with API controller

[Rick-Anderson]

See the middleware version

/api/values/Squareroot/-1 returns the generic type and title
{"type":"https://tools.ietf.org/html/rfc7231#section-6.5.1","title":"Bad Request",
not the type and title that's set
{"type":"https://en.wikipedia.org/wiki/Square_root","title":"Wrong Input"

When I Customize problem details with CustomizeProblemDetails see also source code

the API controller returns the correct problem details.

When I step through the middleware version in the debugger, everything is set correctly.

@sammychinedu2ky

[sammychinedu2ky]

Ok let me check it out

[sammychinedu2ky]

The middleware and controller version seems to work well from my end version seems to work for me from my end @Rick-Anderson
Maybe you need to refresh your Swagger UI if that is what you are using

[sammychinedu2ky]

Ooh sorry I'm mistaken, seems the controller was activated for the middleware as well

[Rick-Anderson]

Maybe you need to refresh your Swagger UI

Speaking of Swagger, maybe we should remove Swagger since it's not needed for the sample.

[sammychinedu2ky]

Maybe you need to refresh your Swagger UI

Speaking of Swagger, maybe we should remove Swagger since it's not needed for the sample.

I'm still trying to figure out why the minimal API is working but the controller isn't.

[Rick-Anderson]

The controller works with CustomizeProblemDetails
Build with #define API_CONTROLLER and test the controller.

[sammychinedu2ky]

Yh I tried that and it worked

[Rick-Anderson]

@brunolins16 can you help with this mystery? When using middleware, API controller problem details are overwritten.
When we Customize problem details with CustomizeProblemDetails see also source code

the API controller returns the correct problem details.

[brunolins16]

Let me check if I understood the issue:

1. Middleware version: the produced ProblemDetails is not what you are expecting.
2. CustomizeProblemDetails version: the ProblemDetails is update with the expected message

If that is the question I can explain:

In the middleware version you are calling the ProblemDetailsService.WriteAsync that has some conditions to work

https://github.com/dotnet/aspnetcore/blob/ce2db7ea0b161fc5eb35710fca6feeafeeac37bc/src/Http/Http.Extensions/src/ProblemDetailsService.cs#L24

As you can see it will be a no-op when the HttpResponse.Body already started that is the case since the API controller produced the PD and started writing to the HttpResponse.Body, so, in this case it is too late. If we don't want to auto-generate problem details in this scenario you will need to disable it Disable ProblemDetails response and it might work as expected.

However, when using the CustomizeProblemDetails the customization delegate will be called when the API Controller ProblemDetails is generated, before writing to the HttpResponse.Body, and in this case we are actually not calling ProblemDetailsService.WriteAsync.

https://github.com/dotnet/aspnetcore/blob/main/src/Mvc/Mvc.Core/src/Infrastructure/DefaultProblemDetailsFactory.cs#L101

[Rick-Anderson]

@brunolins16 awesome. I think I'll explain what's going on in the article. Customers will hit this. I forgot about HttpResponse.Body already started and customers will too.
I think I'll also remove Swagger since it's not needed for Problem details unless you think I should keep it.

[brunolins16]

I think I will update the API comments here (https://github.com/dotnet/aspnetcore/blob/ce2db7ea0b161fc5eb35710fca6feeafeeac37bc/src/Http/Http.Abstractions/src/ProblemDetails/IProblemDetailsService.cs#L22) to explicitly call out it as well.

[Rick-Anderson]

update the API comments here
Agreed.

Should I remove Swagger from the sample code to simplify it?

[sammychinedu2ky]

Thanks @brunolins16 that makes sense 😅

[sammychinedu2ky]

Suppressing the automatic generation of problem details still returns a 400 status code for bad requests

[sammychinedu2ky]

@brunolins16 @Rick-Anderson