MVFC.Mediator 2.0.1

MVFC.Mediator

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A high-performance, zero-allocation dispatcher implementation of the Mediator pattern for .NET 9 and 10. Centralize your business logic, decouple components, and scale with confidence.

Motivation

In complex .NET applications, direct dependencies between services often lead to:

• Tight Coupling: Difficult to test and maintain components.
• Boilerplate: Repetitive logic for validation and orchestration.
• Poor Scalability: Hard to evolve systems as they grow.
• Performance Overhead: Common libraries often introduce hidden allocations and reflection costs.

MVFC.Mediator solves this by providing a lightweight, ultra-fast mediator with a zero-allocation dispatcher pattern. It uses static generic caching and advanced IL techniques to ensure that your message routing is as fast as a direct method call.

Architecture

• Zero-Allocation Dispatchers: Uses Volatile.Read and Interlocked for thread-safe, reflection-free handler invocation.
• Fluent Integration: Seamlessly connects with Microsoft.Extensions.DependencyInjection.
• Validation-First: Built-in support for FluentValidation with parallel execution for multiple validators.
• Fan-out Support: Native notification system for broadcasting events to multiple handlers.

Installation

Install the package via NuGet:

dotnet add package MVFC.Mediator

Quick Start

1. Register with Dependency Injection

builder.Services.AddMediator();

2. Basic Command (No Response)

// Define the command
public record DeleteUserCommand(Guid UserId) : ICommand;

// Implement the handler
public class DeleteUserHandler : ICommandHandler<DeleteUserCommand>
{
    public ValueTask Handle(DeleteUserCommand command, CancellationToken ct)
    {
        // Logic to delete user
        return ValueTask.CompletedTask;
    }
}

// Usage
await mediator.Send(new DeleteUserCommand(uid));

3. Command with Response & Validation

// Response model
public record UserCreated(Guid Id);

// Command with TResponse
public record CreateUser(string Name, string Email) : ICommand<UserCreated>;

// Validator (executed automatically if registered)
public class CreateUserValidator : AbstractValidator<CreateUser>
{
    public CreateUserValidator()
    {
        RuleFor(x => x.Name).NotEmpty().MinimumLength(3);
        RuleFor(x => x.Email).EmailAddress();
    }
}

// Handler
public class CreateUserHandler : ICommandHandler<CreateUser, UserCreated>
{
    public ValueTask<UserCreated> Handle(CreateUser command, CancellationToken ct)
    {
        return new ValueTask<UserCreated>(new UserCreated(Guid.NewGuid()));
    }
}

// Usage
var result = await mediator.Send<CreateUser, UserCreated>(new CreateUser("John", "john@test.com"));

4. Query (Read Logic)

public record GetUserQuery(Guid Id) : IQuery<UserDto>;

public class GetUserHandler : IQueryHandler<GetUserQuery, UserDto>
{
    public async ValueTask<UserDto> Handle(GetUserQuery query, CancellationToken ct)
    {
        return await _repository.GetById(query.Id);
    }
}

// Usage
var user = await mediator.Query<GetUserQuery, UserDto>(new GetUserQuery(uid));

5. Notifications (Event Broadcasting)

public record UserRegistered(Guid Id) : INotification;

// Multiple handlers for the same notification
public class LoggingHandler : INotificationHandler<UserRegistered> { ... }
public class WelcomeEmailHandler : INotificationHandler<UserRegistered> { ... }

// Usage (broadcasting to all handlers)
await mediator.Publish(new UserRegistered(uid));

Performance

Built for high-throughput scenarios, benchmarked on .NET 9.

BenchmarkDotNet v0.15.4, Windows 11 (10.0.26200.6901)
12th Gen Intel Core i5-12500H 2.50GHz, 1 CPU, 16 logical and 12 physical cores
.NET SDK 9.0.302
  [Host]     : .NET 9.0.7 (9.0.7, 9.0.725.31616), X64 RyuJIT x86-64-v3
  Job-NTRUNJ : .NET 9.0.7 (9.0.7, 9.0.725.31616), X64 RyuJIT x86-64-v3

IterationCount=5  WarmupCount=3  

API Reference

Project Structure

src/
  MVFC.Mediator/      # Core logic and Dispatchers
playground/
  Playground.Api/     # Usage examples and Integration tests
tests/
  MVFC.Mediator.Tests # Unit and Architecture tests

Requirements

• .NET 9 or .NET 10

Contributing

See CONTRIBUTING.md.

License

Apache-2.0