ErrorDetailsRFC7807

Launch and test several modes of invoking errors in Server\HttpTools\WeatherForecastController.http like:

See Settings chapter at the end of this file.

Context

I have used 4 ways of generating errors based on this document https://learn.microsoft.com/en-us/aspnet/core/web-api/action-return-types?view=aspnetcore-7.0

• Exception (/WeatherForecast/SimpleException): Result response is compliant to standard definition of AddProblemDetails extensions based on RFC7807

• Error using this feature on IActionResult return type (/WeatherForecast/ErrorFeatureOnIActionResult): Result Response is compliant to customized definition of AddProblemDetails extensions.

• Error using this feature on Results return type (/WeatherForecast/ErrorFeatureOnResults): No body in result Response, it is not compliant to customized defintion of AddProblemDetails extensions.

• Error not using feature or ErrorType based on Results return type but using TypedResult.Problem (WeatherForecast/ErrorFeatureOnResultsUsingTypedResultsProblem): Result Response is compliant to standard definition of AddProblemDetails extensions

Conclusion

My conclusion is that you can use this settings to customize errors by 3 ways:

• Using Exception and AddProblemDetails
• Using IActionResult and AddProblemDetails + ErrorFeature customization
• Using Results, TypedResult.Problem and AddProblemDetails

When possible, I think that the 3rd way of writting API is the preferred one due to contract compilation on possible return types and the easy way of creating its own details.

Settings

In Program.cs

builder.Services.AddProblemDetails(options =>
    options.CustomizeProblemDetails = ctx => // Add custom problem details
    {
      var errorFeature = ctx.HttpContext.Features.Get<ErrorFeature>();
      if (errorFeature is not null)
      {
        ctx.ProblemDetails.Title = errorFeature.Title;
        ctx.ProblemDetails.Detail = errorFeature.Detail;
        ctx.ProblemDetails.Type = errorFeature.ErrorType.ToString();
      }
    });

With this file to define Server\Errors\ErrorFeature

namespace ErrorDetailsRFC7807.Server.Errors;

public record ErrorFeature(ErrorType ErrorType, string? Title = null, string? Detail = null);

public enum ErrorType
{
    ArgumentException,
    InvalidOperationException,
    NotFoundException
}