A lightweight mediator implementation designed for .NET Standard 2.0 and higher. It simplifies request handling by decoupling it from application logic, enabling easier maintenance, better testability, and clean separation of concerns — while leveraging dependency injection through Microsoft.Extensions.DependencyInjection.Abstractions.

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Features

• Target frameworks: netstandard2.0, netstandard2.1, net8.0, net9.0, net472, net48, and net481.
• No external dependencies (except Microsoft.Extensions.DependencyInjection.Abstractions for DI).
• Simple setup and configuration.
• Supports multiple assemblies and namespace filtering.
• Clean, extensible, and minimalistic design.

Note: When targeting .NET Framework 4.7.2, 4.8, or 4.8.1 (net472, net48, net481), the following additional dependencies are required to support modern async/await features:

• Microsoft.Bcl.AsyncInterfaces
• System.Runtime.CompilerServices.Unsafe
• System.Threading.Tasks.Extensions

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Installation

Install via NuGet Package Manager:

Install-Package FloppyShelf.Mediator

Or via .NET CLI:

dotnet add package FloppyShelf.Mediator

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Usage

1. Define a Request

using FloppyShelf.Mediator.Interfaces;

public class GetProductQuery : IRequest<Product>
{
    public int Id { get; set; }
}

2. Implement a RequestHandler

using FloppyShelf.Mediator.Interfaces;

public class GetProductQueryHandler : IRequestHandler<GetProductQuery, Product>
{
    public Task<Product> HandleAsync(GetProductQuery request, CancellationToken cancellationToken)
    {
        // Simulated database access
        return Task.FromResult(new Product { Id = request.Id, Name = "Sample Product" });
    }
}

3. Register the Mediator

using FloppyShelf.Mediator.Extensions;
using Microsoft.Extensions.DependencyInjection;

var services = new ServiceCollection();

// Register handlers from the specified assemblies
services.AddMediator(new[] { typeof(Program).Assembly });

// Optional: Pass a string[] to filter specific namespaces

4. Send a Request

using Microsoft.Extensions.DependencyInjection;

var provider = services.BuildServiceProvider();
var mediator = provider.GetRequiredService<IMediator>();

var result = await mediator.SendAsync(new GetProductQuery { Id = 1 });
Console.WriteLine(result.Name);

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API Overview

Interfaces

• IRequest<TResponse> - Represents a request expecting a response.
• IRequestHandler<TRequest, TResponse> - Handles a specific request.
• IMediator - Sends requests to handlers.

Key Classes

• Mediator - Core implementation of the mediator pattern.
• ServiceCollectionExtensions - Provides the AddMediator() extension method for easy DI setup.

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Why FloppyShelf.Mediator?

• Clean and Minimal - Only the essentials, no magic.
• Fully Open Source - MIT licensed.
• Great for Learning - Understand how mediators work internally.
• Extremely Lightweight - No unnecessary complexity.