How to override JSON property name of file property generated by FluentValidation in ASP .Net Core?

Question

I'm trying to validate file size using FluentValidation in ASP.Net Core 3.1, and it works properly, but the property name generated looks like this:

 {
  "type": "https://tools.ietf.org/html/rfc7231#section-6.5.1",
  "title": "One or more validation errors occurred.",
  "status": 400,
  "traceId": "|f885b78f-4a52ff23c676c331.",
  "errors": {
    "MyFile.Length": [
      "My file: The max file size allowed is 5 Mb."
    ]
  }
}

The problem is that property name generated is "MyFile.Length" and I would like that the result was only "MyFile". My current code is:

InsertMovementValidator.cs

public class InsertMovementValidator : AbstractValidator<InsertMovementDTO>
{
    public InsertMovementValidator ()
    {
        RuleFor(x => x.MyFile).SetValidator(new FileValidator());
    }
}

FileValidator.cs

public class FileValidator : AbstractValidator<IFormFile>
{
    public FileValidator()
    {
        RuleFor(x => x.Length).LessThanOrEqualTo(5242880) //5 Megabytes
            .WithName("My file")
            .WithMessage("{PropertyName}: The max file size allowed is 5 Mb");
    }
}

Thanks in advance.

Answer 1

You can set the Validator like below:

public class InsertMovementValidator : AbstractValidator<InsertMovement>
{
    public InsertMovementValidator()
    {
        
        RuleFor(x => x.MyFile).SetValidator(new FileValidator()).OverridePropertyName(""); 
    }
}

public class FileValidator : AbstractValidator<IFormFile>
{
    public FileValidator()
    {
        RuleFor(x => x.Length).LessThanOrEqualTo(102400) //100 kb
            .OverridePropertyName("My file")
            .WithName("My file")
            .WithMessage("{PropertyName}: The max file size allowed is 100 Kb");
    }
}

Result: