EXCSLA.Shared.Application 5.3.1

EXCSLA.Shared.Application

CQRS Command and Query pattern implementation for the EXCSLA application layer.

Overview

Provides abstractions and implementation for the Command Query Responsibility Segregation (CQRS) pattern without external dependencies.

Key Interfaces

• ICommand - Marker interface for commands
• ICommandHandler<TCommand> - Handler for command execution
• IQuery<TResult> - Query with expected result type
• IQueryHandler<TQuery, TResult> - Handler for query execution
• IDispatcher - Command/Query dispatcher

Installation

dotnet add package EXCSLA.Shared.Application

Usage

Define Commands

public class CreateOrderCommand : ICommand
{
    public OrderNumber OrderNumber { get; set; }
    public CustomerId CustomerId { get; set; }
}

public class CreateOrderHandler : ICommandHandler<CreateOrderCommand>
{
    private readonly IAsyncRepository<Order> _repository;
    
    public async Task Handle(CreateOrderCommand command)
    {
        var order = new Order(command.OrderNumber, command.CustomerId);
        await _repository.AddAsync(order);
    }
}

Define Queries

public class GetOrderByIdQuery : IQuery<OrderDto>
{
    public OrderId Id { get; set; }
}

public class GetOrderByIdHandler : IQueryHandler<GetOrderByIdQuery, OrderDto>
{
    private readonly IAsyncRepository<Order> _repository;
    
    public async Task<OrderDto> Handle(GetOrderByIdQuery query)
    {
        var order = await _repository.GetByIdAsync(query.Id);
        return MapToDto(order);
    }
}

Register in DI

services.AddApplicationServices();

Execute

var command = new CreateOrderCommand { OrderNumber = orderNumber };
await dispatcher.DispatchAsync(command);

var query = new GetOrderByIdQuery { Id = orderId };
var result = await dispatcher.DispatchAsync(query);

Features

• Zero external dependencies (no MediatR required)
• Type-safe command/query dispatch
• Async/await patterns
• IServiceProvider integration
• Decorator pattern support

Building Blocks

• Commands - Write operations
• Queries - Read operations
• Handlers - Business logic
• Dispatcher - Orchestration

Dependencies

• .NET 10.0 or higher

License

See LICENSE file in repository

Support

For issues and questions, visit the GitHub repository