CleanMediator 1.0.1

CleanMediator

CleanMediator is a lightweight mediator and pipeline behavior library tailored for Clean Architecture projects. It provides structured request/response handling with optional middleware-style pipeline behaviors for pre- and post-processing logic such as logging, validation, caching, etc.

✨ Features

• Minimal setup, zero external dependencies.
• Supports both commands (IRequest) and queries (IRequest<T>)
• Pipeline behaviors for clean cross-cutting concerns
• Automatic handler and behavior discovery
• Built-in dependency injection support
• Fully unit-testable
• .NET 8+ compatible

📦 Installation

Install via NuGet:

dotnet add package CleanMediator

🚀 Getting Started

1. Register CleanMediator

builder.Services.AddCleanMediator();

This will automatically register:

• All IRequestHandler<TRequest> and IRequestHandler<TRequest, TResponse> implementations
• All IPipelineBehavior<TRequest> and IPipelineBehavior<TRequest, TResponse> behaviors

2. Create a Request (Query)

public class GetUserByIdQuery : IRequest<UserResponse>
{
    public int Id { get; set; }
}

3. Create a Handler

public class GetUserByIdHandler : IRequestHandler<GetUserByIdQuery, UserResponse>
{
    public Task<UserResponse> HandleAsync(GetUserByIdQuery request, CancellationToken cancellationToken)
    {
        return Task.FromResult(new UserResponse
        {
            Id = request.Id,
            Name = "Jane Doe"
        });
    }
}

4. Dispatch from Code (Controller)

[Route("api/[controller]")]
    [ApiController]
    public class UsersController(IRequestDispatcher dispatcher) : ControllerBase
    {
        private readonly IRequestDispatcher _dispatcher = dispatcher;

        [HttpGet("{id}")]
        public async Task<IActionResult> GetUserAsync(int id)
        {
            var result = await _dispatcher.SendAsync(new GetUserByIdQuery{ Id = id });
            return Ok(result);
        }
    }

🔁 Commands (No Response)

public class DeactivateUserCommand : IRequest
{
    public int UserId { get; set; }
}

public class DeactivateUserHandler : IRequestHandler<DeactivateUserCommand>
{
    public Task HandleAsync(DeactivateUserCommand request, CancellationToken cancellationToken)
    {
        Console.WriteLine($"User {request.UserId} deactivated");
        return Task.CompletedTask;
    }
}

[HttpPut("{id}")]
public async Task<IActionResult> DeactivateUserAsync(int id)
{
    await _dispatcher.SendAsync(new DeactivateUserCommand { UserId = id });
    return Ok("User Deactivated Successfully.");
}

🧩 Pipeline Behaviors

1. Logging Behavior (Generic)

public class LoggingBehavior<TRequest, TResponse> : IPipelineBehavior<TRequest, TResponse>
    where TRequest : IRequest<TResponse>
{
    public async Task<TResponse> HandleAsync(TRequest request, Func<Task<TResponse>> next, CancellationToken cancellationToken)
    {
        Console.WriteLine($"Handling {typeof(TRequest).Name}");
        var response = await next();
        Console.WriteLine($"Handled {typeof(TRequest).Name}");
        return response;
    }
}

2. Validation Behavior (Non-Generic)

public class ValidationBehavior<TRequest> : IPipelineBehavior<TRequest>
    where TRequest : IRequest
{
    public async Task HandleAsync(TRequest request, Func<Task> next, CancellationToken cancellationToken)
    {
        Console.WriteLine($"Validating {typeof(TRequest).Name}");
        await next();
    }
}

🧪 Unit Testing

Use xUnit + Shouldly for clean tests:

[Fact]
public async Task Dispatch_GenericRequest_ReturnsExpectedResponse()
{
    var services = new ServiceCollection();
    services.AddScoped<IRequestDispatcher, RequestDispatcher>();
    services.AddScoped<IRequestHandler<GetUserByIdQuery, UserResponse>, GetUserByIdHandler>();

    var provider = services.BuildServiceProvider();
    var dispatcher = provider.GetRequiredService<IRequestDispatcher>();

    var result = await dispatcher.SendAsync(new GetUserByIdQuery { Id = 1 });
    result.Name.ShouldBe("Jane Doe");
}

📂 Folder Structure Suggestion

src/
  CleanMediator/           --> NuGet package source
test/
  CleanMediator.Tests/     --> Unit tests with xUnit and Shouldly

📜 License

This project is licensed under the MIT License.

🤝 Contributing

Contributions are welcome! Please fork, fix, and submit a PR. Open issues if you have questions or suggestions.

🌐 Links

• NuGet Package
• GitHub Issues
• License