Is it possible to control the schema response in ASP.NET Core?

[xplatsolutions]

I would like to set my own response schema in the 400 Bad Request response.

e.g.

{
    "type": "https://tools.ietf.org/html/rfc7231#section-6.5.1",
    "title": "One or more validation errors occurred.",
    "status": 400,
    "traceId": "00-0a4404bdf847cb8cf5f696aac649ee61-5dff3d630c7d9c63-00",
    "errors": {
        "ShownGenderOnProfile": [
            "ShownGenderOnProfile must not be empty"
        ]
    }
}

I am using the auto-validation package SharpGrip.FluentValidation.AutoValidation.Mvc.

[mvdgun]

Hi @xplatsolutions, interesting feature. Perhaps it's already possible by customizing the default problem details as explained here: https://learn.microsoft.com/en-us/aspnet/core/web-api/handle-errors?view=aspnetcore-7.0#implement-problemdetailsfactory.

Let me look into it and if it's not possible I'll integrate it into the MVC package and perhaps the Minimal APIs package.

[xplatsolutions]

That would be amazing if we figure it out, can be tricky but I imagine something like adding our own JSON for each error.

Example:

{
   "errorCode":200,
   "domainCode":100,
   "errors":{
      "ShownGenderOnProfile":[
         {
            "domainCode":4,
            "errorCode":20,
            "errorMessage":"ShownGenderOnProfile must not be empty",
            "data":null
         }
      ]
   }
}

[mvdgun]

I just finished the initial work for a custom result factory. In your case it would work something like this:

using SharpGrip.FluentValidation.AutoValidation.Mvc.Extensions;

builder.Services.AddFluentValidationAutoValidation(configuration =>
{
    // Replace the default result factory with a custom implementation.
    configuration.OverrideDefaultResultFactoryWith<CustomResultFactory>();
});

public class CustomResultFactory : IFluentValidationAutoValidationResultFactory
{
    public IActionResult CreateActionResult(ActionExecutingContext context, ValidationProblemDetails? validationProblemDetails)
    {
        return new BadRequestObjectResult(new {Title = "Validation errors", ValidationErrors = validationProblemDetails?.Errors});
    }
}

You can return a fully custom response when the model state is invalid. You will be able to access the ValidationProblemDetails containing the validation errors and the full ActionExecutingContext. Would something like this help you?

[xplatsolutions]

This looks like exactly what I need to create my own custom response for all the errors! I can try it out ASAP if you want :)

[mvdgun]

Hi @xplatsolutions, I just released the v1.1.0 versions of the packages containing the option for providing a custom result factory.

[xplatsolutions]

I will check it out ASAP! Thanks for this one

[xplatsolutions]

Confirming the approach worked like a charm! Thank you

[mvdgun]

Awesome! Thanks for getting back.