Midas.Validation 1.0.6

Midas.Validation

FluentValidation base classes and extensions for .NET healthcare applications.
Built by Midas Path Software Solutions for clean-architecture HMS systems.

Installation

dotnet add package Midas.Validation

Quick Start

1. Create a validator

using FluentValidation;
using Midas.Validation;

public class RegisterPatientCommandValidator : MidasValidator<RegisterPatientCommand>
{
    public RegisterPatientCommandValidator()
    {
        RuleFor(x => x.FullName)
            .NotEmpty()
            .MaximumLength(200);

        // Built-in domain rules
        GhanaPhone(RuleFor(x => x.PhoneNumber));
        NhisId(RuleFor(x => x.NhisId));
        EmailAddress(RuleFor(x => x.Email));
        NotFutureDate(RuleFor(x => x.DateOfBirth));
    }
}

2. Register in Program.cs (once)

builder.Services.AddMidasValidators(
    typeof(RegisterPatientCommandValidator).Assembly
);

3. Use in a MediatR pipeline behaviour

public class ValidationBehaviour<TRequest, TResponse>(
    IEnumerable<IValidator<TRequest>> validators)
    : IPipelineBehavior<TRequest, TResponse>
{
    public async Task<TResponse> Handle(TRequest request, RequestHandlerDelegate<TResponse> next, CancellationToken ct)
    {
        var context = new ValidationContext<TRequest>(request);
        var results = await Task.WhenAll(validators.Select(v => v.ValidateAsync(context, ct)));
        var failures = results.SelectMany(r => r.Errors).Where(f => f is not null).ToList();

        if (failures.Count > 0)
            throw new MidasValidationException(failures);

        return await next();
    }
}

4. Map to RFC 7807 Problem Details in the API layer

app.UseExceptionHandler(builder => builder.Run(async context =>
{
    var ex = context.Features.Get<IExceptionHandlerFeature>()?.Error;
    if (ex is MidasValidationException ve)
    {
        context.Response.StatusCode = 422;
        await context.Response.WriteAsJsonAsync(new ValidationProblemDetails(ve.ToDictionary()));
    }
}));

Built-in Domain Rules

All helpers return IRuleBuilderOptions<T, TProp> so you can chain additional FluentValidation rules.

API Reference

MidasValidator<T>

Abstract base class extending AbstractValidator<T>. Provides the domain rule helpers above.

MidasValidationException

Thrown when validation fails. Carries IReadOnlyList<ValidationFailure> Errors.
ToDictionary() returns IDictionary<string, string[]> for ValidationProblemDetails.

ValidationExtensions

• result.ToDictionary() — converts a ValidationResult to a field→messages dictionary
• result.ThrowIfInvalid() — throws MidasValidationException if result is invalid

AddMidasValidators(params Assembly[])

Scans assemblies for IValidator<T> implementations and registers them as scoped services.

Target Frameworks

• net9.0

License

MIT © Midas Path Software Solutions