GM.Mediator 1.3.3

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GM.Mediator

A lightweight, dependency-injection-friendly mediator for .NET — send requests, publish notifications, and wrap handlers in pipeline behaviors, with no external dependencies beyond Microsoft.Extensions.DependencyInjection.Abstractions.

Targets net10.0.

Install

dotnet add package GM.Mediator

Register

Scan one or more assemblies for handlers and behaviors:

using GM.Mediator;

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

// Optional: choose the service lifetime (defaults to Scoped)
services.AddGMMediator(ServiceLifetime.Transient, typeof(Program).Assembly);

Requests with a response

public record GetUser(int Id) : IRequest<UserDto>;

public class GetUserHandler : IRequestHandler<GetUser, UserDto>
{
    public Task<UserDto> Handle(GetUser request, CancellationToken ct) => /* ... */;
}

// usage
UserDto user = await mediator.Send(new GetUser(42));

Requests without a response

public record DeleteUser(int Id) : IRequest;

public class DeleteUserHandler : IRequestHandler<DeleteUser>
{
    public Task Handle(DeleteUser request, CancellationToken ct) => /* ... */;
}

await mediator.Send(new DeleteUser(42));

Notifications (multiple handlers)

public record UserCreated(int Id) : INotification;

public class SendWelcomeEmail : INotificationHandler<UserCreated> { /* ... */ }
public class UpdateAnalytics  : INotificationHandler<UserCreated> { /* ... */ }

await mediator.Publish(new UserCreated(42)); // both handlers run

Pipeline behaviors

Behaviors wrap handlers and run in registration order (first registered = outermost). Both response and no-response variants are supported.

public class LoggingBehavior<TRequest, TResponse> : IPipelineBehavior<TRequest, TResponse>
{
    public async Task<TResponse> Handle(TRequest request, RequestHandlerDelegate<TResponse> next, CancellationToken ct)
    {
        // before
        var response = await next();
        // after
        return response;
    }
}

Open generic behaviors are registered automatically by AddGMMediator.

License

MIT — see LICENSE.