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ModulesValidation

Validation

Griffin.Validation supplies a MediatR pipeline behavior that runs FluentValidation validators on incoming requests.

Installation

dotnet add package Griffin.Validation

Register the Behavior

Register ValidationBehavior<,> as a MediatR pipeline behavior in your service collection, alongside your IValidator<T> implementations.

using FluentValidation;
 
public sealed class CreateOrderValidator : AbstractValidator<CreateOrder>
{
    public CreateOrderValidator()
    {
        RuleFor(x => x.Reference).NotEmpty();
    }
}

The behavior resolves IValidator<TRequest> from the service provider for each request. When a validator is present it calls the request validation; requests without a registered validator pass through unchanged.

Failure Behavior

Validation failures throw Griffin.Core.Exception.ValidationException carrying the first validation error message. Later errors are not included. This exception can then be mapped to a client-facing response through Problem Details.

HandleValidationAsync is a convenience extension that performs ValidateAsync and throws the core ValidationException. Use it directly when you need the same validation behavior outside the MediatR pipeline.

Design validators to keep the most useful message first, or use a custom exception mapper if you must surface every error.

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