ReValidator.Validation.Mvc 1.0.0

ReValidator.Validation.Mvc

ReValidator.Validation.Mvc is a lightweight, generic validation adapter for ASP.NET Core MVC, built on top of the ReValidator engine. It allows you to apply strongly-typed, reusable validators to controller parameters using a simple [Validate] attribute, with full support for dependency injection and dynamic rules.

This package is fully compatible with .NET 6, 7, 8, 9, and works seamlessly alongside MVC.

Features

• Apply [Validate] to any controller parameter.
• Leverages your existing IValidator<T> implementations.
• Returns structured validation errors (RFC-7807 style).
• Supports dynamic rule injection at runtime.
• Optionally configure global MVC validation filter.
• Compatible with MVC for consistent behavior.
• Returns HTTP 422 Unprocessable Entity for failed validations.

Installation

Install via NuGet:

dotnet add package ReValidator.Validation.Mvc

Usage

1. Add ReValidator services in Program.cs

var builder = WebApplication.CreateBuilder(args);

// Add core ReValidator services
builder.Services.AddReValidator();

// Add MVC support
builder.Services.AddControllers();
builder.Services.AddReValidatorMvc();

// Optional: add global filter
// or add the mentioned filter per controller's action
builder.Services.AddControllers(options =>
{
    options.Filters.Add<ReValidatorActionFilter>();
});

var app = builder.Build();
app.MapControllers();
app.Run();

2. Create a validator

public sealed class PersonValidator : IValidator<Person>
{
    public ValidationResult Validate(Person model)
    {
        var result = new ValidationResult();

        if (string.IsNullOrWhiteSpace(model.Name))
            result.Errors.Add(new ValidationError
            {
                Rule = "FullNameRequired",
                Message = "The 'Name' property is required."
            });

        return result;
    }
}

3. Apply [Validate] to controller parameters

[ApiController]
[Route("persons")]
public sealed class PersonsController : ControllerBase
{
    [HttpPost("create")]
    public IActionResult Create([Validate] Person person)
    {
        // This action will only execute
    }
}

4. Dynamic rule injection

app.Services.ApplyReconfiguration(new DynamicReconfiguration
{
    RuleName = "FullNameRequired",
    PropertyName = "Name",
    ErrorMessage = "The \"{PropertyName}\" is required",
    Expression = "x => !string.IsNullOrWhiteSpace(x.Name)",
    FullPathToModel = typeof(Person).FullName
});

This allows you to inject or update rules at runtime, without recompiling validators.

5. Validation response

When a validation fails, the API returns HTTP 422 with a structured payload:

{
  "type": "about:blank",
  "title": "Validation failed",
  "status": 422,
  "detail": "One or more validation rules were violated.",
  "errors": [
    {
      "rule": "FullNameRequired",
      "message": "The 'Name' property is required."
    }
  ]
}

Unit Testing

You can use Microsoft.AspNetCore.TestHost to test MVC endpoints:

using var app = await CreateApplication();
var client = app.GetTestClient();

var response = await client.PostAsJsonAsync("/persons/create", new Person());
Assert.Equal(422, (int)response.StatusCode);

Requirements

• NET 6.0 or higher
• ReValidator.Contracts
• ASP.NET Core MVC (Abstractions + Core)