MediatR

CQRS with MediatR in .NET Core.

Command

public class InsertProductCommand : IRequest
{
   public string Description { get; set; }
}

CommandHandler

public class InsertProductCommandHandler : AsyncRequestHandler<InsertProductCommand>
{
    private readonly IMediator _mediator;

    public InsertProductCommandHandler(IMediator mediator)
    {
        _mediator = mediator;
    }

    protected override Task Handle(InsertProductCommand command, CancellationToken cancellationToken)
    {
        var entity = ProductFactory.Create(command);

        _mediator.Publish(new ProductInsertedNotification(entity));

        return Task.CompletedTask;
    }
}

Query

public class GetByIdProductQuery : IRequest<ProductViewModel>
{
    public long Id { get; set; }
}

QueryHandler

public class GetByIdProductQueryHandler : IRequestHandler<GetByIdProductQuery, ProductViewModel>
{
    public Task<ProductViewModel> Handle(GetByIdProductQuery query, CancellationToken cancellationToken)
    {
        return Task.FromResult(new ProductViewModel { Id = query.Id });
    }
}

Notification

public class ProductInsertedNotification : INotification
{
    public ProductInsertedNotification(ProductEntity product)
    {
        Product = product;
    }

    public ProductEntity Product { get; private set; }
}

NotificationHandler

public class ProductInsertedNotificationHandler : INotificationHandler<ProductInsertedNotification>
{
    public Task Handle(ProductInsertedNotification notification, CancellationToken cancellationToken)
    {
        return Task.CompletedTask;
    }
}

Tests

[TestClass]
public class ProductTest
{
    private readonly IMediator _mediator;

    public ProductTest()
    {
        var services = new ServiceCollection();

        services.AddMediatR(typeof(InsertProductCommand));

        _mediator = services.BuildServiceProvider().GetService<IMediator>();
    }

    [TestMethod]
    public async Task Delete()
    {
        var command = new DeleteProductCommand { Id = 1 };

        await _mediator.Send(command);
    }

    [TestMethod]
    public async Task GetById()
    {
        var query = new GetByIdProductQuery { Id = 1 };

        var result = await _mediator.Send(query);
    }

    [TestMethod]
    public async Task Insert()
    {
        var command = new InsertProductCommand { Description = "Description" };

        await _mediator.Send(command);
    }

    [TestMethod]
    public async Task Update()
    {
        var command = new UpdateProductCommand { Id = 1, Description = "Description" }; ;

        await _mediator.Send(command);
    }
}

Feature Folders

Category

Delete

    DeleteCategoryCommand.cs

    DeleteCategoryCommandResult.cs

    DeleteCategoryCommandValidator.cs

    DeleteCategoryCommandHandler.cs

Insert

    InsertCategoryCommand.cs

    InsertCategoryCommandResult.cs

    InsertCategoryCommandValidator.cs

    InsertCategoryCommandHandler.cs

List

    ListCategoryQuery.cs

    ListCategoryQueryResult.cs

    ListCategoryQueryValidator.cs

    ListCategoryQueryHandler.cs

Update

    UpdateCategoryCommand.cs

    UpdateCategoryCommandResult.cs

    UpdateCategoryCommandValidator.cs

    UpdateCategoryCommandHandler.cs

Product

Delete

    DeleteProductCommand.cs

    DeleteProductCommandResult.cs

    DeleteProductCommandValidator.cs

    DeleteProductCommandHandler.cs

Insert

    InsertProductCommand.cs

    InsertProductCommandResult.cs

    InsertProductCommandValidator.cs

    InsertProductCommandHandler.cs

List

    ListProductQuery.cs

    ListProductQueryResult.cs

    ListProductQueryValidator.cs

    ListProductQueryHandler.cs

SelectById

    SelectByIdProductQuery.cs

    SelectByIdProductQueryResult.cs

    SelectByIdProductQueryValidator.cs

    SelectByIdProductQueryHandler.cs

Update

    UpdateProductCommand.cs

    UpdateProductCommandResult.cs

    UpdateProductCommandValidator.cs

    UpdateProductCommandHandler.cs

UpdateCategory

    UpdateCategoryProductCommand.cs

    UpdateCategoryProductCommandResult.cs

    UpdateCategoryProductCommandValidator.cs

    UpdateCategoryProductCommandHandler.cs

UpdatePrice

    UpdatePriceProductCommand.cs

    UpdatePriceProductCommandResult.cs

    UpdatePriceProductCommandValidator.cs

    UpdatePriceProductCommandHandler.cs