IExceptionHandlerFeature is not available in CustomizeProblemDetails when using UseDeveloperExceptionPage

[bjornen77]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

The IExceptionHandlerFeature is not available in CustomizeProblemDetails when using "UseDeveloperExceptionPage". It is, however, available when using "UseExceptionHandler()". Is there a reason for this? It would be good to be able to customize the problem details also when using the DeveloperExceptionPage.

Expected Behavior

The IExceptionHandlerFeature is available when using DeveloperExceptionPage

Steps To Reproduce

Try the "/" endpoint from swagger.

using Microsoft.AspNetCore.Diagnostics;

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

builder.Services.AddProblemDetails(configure =>
    configure.CustomizeProblemDetails = (context) =>
    {
        if (context.HttpContext.Features.Get<IExceptionHandlerFeature>() is IExceptionHandlerFeature exceptionHandlerFeature)
        {
            Console.WriteLine("This will not print when using UseDeveloperExceptionPage()");
        }
    }
);

var app = builder.Build();

app.UseDeveloperExceptionPage();

app.UseSwagger();
app.UseSwaggerUI();

app.MapGet("/", () =>
{
    throw new Exception();
});

app.Run();

Exceptions (if any)

No response

.NET Version

7.0.201

Anything else?

No response

[captainsafia]

The IExceptionHandlerFeature is not available in CustomizeProblemDetails when using "UseDeveloperExceptionPage". It is, however, available when using "UseExceptionHandler()". Is there a reason for this?

The exception handling middleware has the potential to re-execute the middleware pipeline so the IExceptionHandlerFeature is used to store details that need to be persisted across re-executions. We could definitely set it in the developer-exception page but there isn't a strong technically requirement to.

Question: Is there a particular reason you are wanting to use the IExceptionHandlerFeature?

The only info that you can get in the IExceptionHandlerFeature that isn't already in the ProblemDetailsContext is the original Exception that you access via IExceptionHandlerFeature.Error.

Hi @bjornen77. We have added the "Needs: Author Feedback" label to this issue, which indicates that we have an open question for you before we can take further action. This issue will be closed automatically in 7 days if we do not hear back from you by then - please feel free to re-open it if you come back to this issue after that time.

[bjornen77]

I want to be able to customize the problem details extensions property with information from the original exception. The reason is that a receiving application always should be able read the customized information in the problem details response.

I know that i can create a custom exception handler also for development purposes, but it would be nice to use the built-in one. Also, it would also be more consistent(when "CustomizeProblemDetails" is called in both cases)

I think that it might be easy to set the IExceptionHandlerFeature in the developer-exception-page. I could try to make a PR for it if wanted.

[captainsafia]

@bjornen77 Thanks! A PR is definitely welcome. It helps to reuse the existing feature here.