开源的 CQRS 和 DDD 风格的 .NET 框架Revo

Revo 是一个开源框架，适用于使用 Event Sourcing 、CQRS 和 DDD 构建的现代化 .NET 应用程序。.

• Domain-Driven Design

• Event Sourcing

• CQRS

• SOA

• Sagas

• 授权

• 多租户

• 数据访问

• 数据库迁移

• 审计

那么使用 Revo 编写程序的是什么样的呢? 下面是一个非常简单的 todo 示例。

Event

任务更新时的事件

public class TodoRenamedEvent : DomainAggregateEvent
{
    public TodoRenamedEvent(string name)
    {
        Name = name;
    }

    public string Name { get; }
}

Aggregate

public class Todo : EventSourcedAggregateRoot
{
    public Todo(Guid id, string name) : base(id)
    {
        Rename(name);
    }
    
    protectedTodo(Guid id) : base(id)
    {
    }

    public string Name { get; private set; }

    public void Rename(string name)
    {
        if (!Name != name)
        {
            Publish(new TodoRenamedEvent(name));
        }
    }
    
    private void Apply(TodoRenamedEvent ev)
    {
        Name = ev.Name;
    }
}

Command

public class CreateTodoCommand : ICommand
{
    public CreateTodoCommand(string name)
    {
        Name = name;
    }

    [Required]
    public string Name { get; }
}

CommandHandler

public class TodoCommandHandler : ICommandHandler<CreateTodoCommand>
{
    private readonly IRepository repository;
    
    public TodoCommandHandler(IRepository repository)
    {
        this.repository = repository;
    }

    public Task HandleAsync(CreateTodoCommand command, CancellationToken cancellationToken)
    {
        var todo = new Todo(command.Id);
        todo.Rename(command.Name);
        repository.Add(todoList);
        return Task.CompletedTask;
    }   
}

Query

public class GetTodosQuery : IQuery<IQueryable<TodoReadModel>>
{
}

Query Handler

public class TaskQueryHandler : IQueryHandler<GetTodoQuery, IQueryable<TodoReadModel>>
{
    private readonly IReadRepository readRepository;

    public TaskListQueryHandler(IReadRepository readRepository)
    {
        this.readRepository = readRepository;
    }

    public Task<IQueryable<TodoReadModel>> HandleAsync(GetTodoListsQuery query, CancellationToken cancellationToken)
    {
        return Task.FromResult(readRepository
            .FindAll<TodoListReadModel>());
    }
}

ASP.NET Core controller

[Route("todos")]
public class TodoController : CommandApiController
{
    [HttpGet("")]
    public Task<IQueryable<TodoReadModel>> Get()
    {
        return CommandBus.SendAsync(new GetTodosQuery());
    }

    [HttpPost("")]
    public Task Post([FromBody] CreateTodoDto payload)
    {
        return CommandBus.SendAsync(new CreateTodoCommand(payload.Name));
    }
    
    public class CreateTodoDto
    {
        public string Name { get; set; }
    }
}

社区非常棒的并且成熟的 DDD 框架，感兴趣的同学可以学习一下。 

https://github.com/revoframework/Revo