Utils.DotNetCore.CQRS 1.1.0

NanoMediator Library Documentation

The NanoMediator is a lightweight CQRS (Command Query Responsibility Segregation) pattern implementation for .NET, providing a minimal mediator without third-party dependencies.

🔧 Setup

1. Register the Mediator

It is possible to use a NuGet package, as example:

dotnet add package Utils.DotNetCore.CQRS --version 1.1.0

v1.1.0: The package targets net8.0 and net10.0; netstandard2.0 is no longer supported. Projects that still need netstandard2.0 should stay on v1.0.3.

Breaking change in v1.0.3: The root namespace was renamed from utils_netcore_cqrs to Utils.DotNetCore.CQRS. If you are upgrading from v1.0.2 or earlier, update all using utils_netcore_cqrs; directives to using Utils.DotNetCore.CQRS;.

In your Startup.cs or Program.cs for minimal hosting (ASP.NET Core or Console App), register the NanoMediator with:

services.AddNanoMediator(typeof(Program).Assembly);

You can pass any type from the assembly that contains your handlers. The method will scan and register all handlers implementing IDataRequestHandler<,>.

🧩 Core Interfaces

IDataRequest<TDataResponse>

Represents a request that returns a response of type TDataResponse.

public interface IDataRequest<TDataResponse> { }

IDataRequestHandler<TDataRequest, TDataResponse>

Handler interface for processing IDataRequest.

public interface IDataRequestHandler<TDataRequest, TDataResponse>
    where TDataRequest : IDataRequest<TDataResponse>
{
    Task<TDataResponse> Handle(TDataRequest request, CancellationToken cancellationToken = default);
}

⚙️ Using the Mediator

Inject NanoMediator

Use constructor injection to access NanoMediator:

public class SomeService
{
    private readonly INanoMediator _mediator;

    public SomeService(INanoMediator mediator)
    {
        _mediator = mediator;
    }

    public async Task DoWorkAsync()
    {
        var result = await _mediator.Send(new SomeQuery());
    }
}

📦 Example

Define a Query

public class CurrentTimeQuery : IDataRequest<string> { }

Implement the Handler

public class CurrentTimeQueryHandler : IDataRequestHandler<CurrentTimeQuery, string>
{
    public Task<string> Handle(CurrentTimeQuery request, CancellationToken cancellationToken = default)
    {
        return Task.FromResult(DateTime.Now.ToString("T"));
    }
}

Send the Query

var currentTime = await _mediator.Send(new CurrentTimeQuery());
Console.WriteLine(currentTime);

🧪 Sample Projects

This repository includes:

• NanoMediatorConsoleSample — demonstrates basic query/command usage.
• NanoMediatorAspNetSample — shows integration with EF Core and Web APIs.

✅ Benefits

• Minimal abstraction
• No third-party packages required
• Ideal for microservices and lightweight applications

📁 Source Files

• NanoMediator.cs: Nano Mediator implementation
• INanoMediator.cs : Nano Mediator interface
• IDataRequest.cs: Request interface
• IDataRequestHandler.cs: Handler interface
• ServiceCollectionExtensions.cs: Dependency injection extensions

📝 License

This project is licensed under the MIT License