TS.MediatR 9.0.6

TS.MediatR

TS.MediatR is a lightweight and flexible CQRS/Mediator library for .NET. It supports IRequest, INotification, IPipelineBehavior, and works seamlessly with Dependency Injection.

🔧 Installation

Install via NuGet:

dotnet add package TS.MediatR

🚀 Getting Started

using TS.MediatR;

services.AddMediatR(options =>
{
    options.AddRegisterAssemblies(typeof(Program).Assembly);
    options.AddOpenBehavior(typeof(LoggingBehavior<,>)); //with response
    options.AddOpenBehavior(typeof(ValidationBehavior<>)); //no response
});

🧩 IRequest / IRequestHandler

Define a request and its corresponding handler:

With Response

public class GetUserQuery : IRequest<UserDto>
{
    public int Id { get; set; }
}

public class GetUserQueryHandler : IRequestHandler<GetUserQuery, UserDto>
{
    public Task<UserDto> Handle(GetUserQuery request, CancellationToken cancellationToken)
    {
        var user = new UserDto { Id = request.Id, Name = "Jhon Doe" };
        return Task.FromResult(user);
    }
}

No Response

public class CreateUserCommand : IRequest
{
    public string Name { get; set; }
}

public class GetUserQueryHandler : IRequestHandler<CreateUserCommand>
{
    public Task Handle(GetUserQuery request, CancellationToken cancellationToken)
    {
        var user = new UserDto { Name = request.Name };
        return Task.FromResult(user);
    }
}

📤 Sending with ISender

Use ISender to send the request:

With Response

var result = await sender.Send(new GetUserQuery { Id = 1 });
Console.WriteLine(result.Name);

No Response

await sender.Send(new CreateUserCommand { Name = "Jhon Doe" });

🔁 Pipeline Behavior

Use IPipelineBehavior for cross-cutting concerns like logging, validation, etc.

With Response

public class LoggingBehavior<TRequest, TResponse> : IPipelineBehavior<TRequest, TResponse>
    where TRequest : IRequest<TResponse>
{
    public async Task<TResponse> Handle(TRequest request, RequesteHandlerDelete<TResponse> next, CancellationToken cancellationToken)
    {
        Console.WriteLine($"Request received: {typeof(TRequest).Name}");
        var response = await next();
        Console.WriteLine($"Response returned: {typeof(TResponse).Name}");
        return response;
    }
}

No Response

public class ValidationBehavior<TRequest> : IPipelineBehavior<TRequest>
    where TRequest : IRequest
{
    public async Task Handle(TRequest request, RequesteHandlerDelete<TResponse> next, CancellationToken cancellationToken)
    {
        Console.WriteLine($"Request received: {typeof(TRequest).Name}");
        await next();
        Console.WriteLine($"Response returned: {typeof(TResponse).Name}");
        return response;
    }
}

📣 Notification Handling

Define a notification and its handler:

public class ProductCreatedEvent : INotification
{
    public Guid Id { get; set; }
    public ProductCreatedEvent(Guid id)
    {
        Id = id;
    }
}

public class SendEmailHandler : INotificationHandler<ProductCreatedEvent>
{
    public Task Handle(ProductCreatedEvent notification, CancellationToken cancellationToken)
    {
        Console.WriteLine($"Id sent: {notification.Id}");
        return Task.CompletedTask;
    }
}

Publish a notification:

await sender.Publish(new ProductCreatedEvent(product.Id));

📦 Features

• ✅ Request/Response (IRequest, IRequest<TResponse>)
• ✅ Notifications (INotification)
• ✅ Pipeline behaviors (IPipelineBehavior)
• ✅ Dependency Injection ready
• ✅ Scoped resolution and handler chaining
• ✅ Fully async support

📁 License

Licensed under the MIT License.