T2FGame.Core 1.0.9

T2FGame.Core

T2FGame 框架的核心库，提供 DDD 构建块、Result 模式、领域事件等基础设施。

功能特性

• DDD 构建块：Entity、AggregateRoot、ValueObject、Repository 接口
• Result 模式：函数式错误处理，避免异常滥用
• 领域事件：事件定义、事件总线、事件处理器
• 领域事件分发器：AggregateRoot 与 EventBus 集成

安装

<PackageReference Include="T2FGame.Core" />

核心组件

1. DDD 构建块

Entity（实体）

public class Player : Entity<long>
{
    public string Name { get; private set; }
    public int Level { get; private set; }

    public Player(long id, string name) : base(id)
    {
        Name = name;
        Level = 1;
    }

    public void LevelUp()
    {
        Level++;
    }
}

AggregateRoot（聚合根）

public class Order : AggregateRoot<Guid>
{
    public long UserId { get; private set; }
    public OrderStatus Status { get; private set; }
    private readonly List<OrderItem> _items = new();

    public Order(Guid id, long userId) : base(id)
    {
        UserId = userId;
        Status = OrderStatus.Created;

        // 添加领域事件
        AddDomainEvent(new OrderCreatedEvent(id, userId));
    }

    public void Complete()
    {
        Status = OrderStatus.Completed;
        AddDomainEvent(new OrderCompletedEvent(Id));
    }
}

ValueObject（值对象）

public class Money : ValueObject
{
    public decimal Amount { get; }
    public string Currency { get; }

    public Money(decimal amount, string currency)
    {
        Amount = amount;
        Currency = currency;
    }

    protected override IEnumerable<object> GetEqualityComponents()
    {
        yield return Amount;
        yield return Currency;
    }
}

2. Result 模式

基本用法

// 成功结果
Result<Player> success = Result.Success(player);

// 失败结果
Result<Player> failure = Result.Failure<Player>(
    Error.NotFound("Player.NotFound", "玩家不存在"));

// 链式调用
var result = await GetPlayerAsync(playerId)
    .Bind(player => ValidatePlayer(player))
    .Map(player => player.ToDto())
    .Match(
        onSuccess: dto => Ok(dto),
        onFailure: error => BadRequest(error.Message)
    );

预定义错误

// 验证错误
Error.Validation("Field.Invalid", "字段格式不正确");

// 未找到错误
Error.NotFound("Entity.NotFound", "实体不存在");

// 冲突错误
Error.Conflict("Entity.Conflict", "实体已存在");

// 未授权错误
Error.Unauthorized("Auth.Failed", "认证失败");

3. 领域事件

定义事件

public record PlayerCreatedEvent(long PlayerId, string Name) : IDomainEvent
{
    public Guid EventId { get; } = Guid.NewGuid();
    public DateTime OccurredOn { get; } = DateTime.UtcNow;
}

事件处理器

public class PlayerCreatedHandler : IEventHandler<PlayerCreatedEvent>
{
    public async Task HandleAsync(PlayerCreatedEvent @event, CancellationToken cancellationToken)
    {
        // 处理事件逻辑
        Console.WriteLine($"玩家 {@event.Name} 已创建");
    }
}

事件发布

public class PlayerService
{
    private readonly IEventBus _eventBus;

    public async Task CreatePlayerAsync(string name)
    {
        var player = new Player(name);

        // 发布事件（等待处理完成）
        await _eventBus.PublishAsync(new PlayerCreatedEvent(player.Id, name));

        // 或者 Fire-and-Forget
        _eventBus.PublishFireAndForget(new PlayerCreatedEvent(player.Id, name));
    }
}

4. Repository 接口

// 通用仓储接口
public interface IRepository<TEntity, TId>
{
    Task<TEntity?> GetByIdAsync(TId id, CancellationToken cancellationToken = default);
    Task<IReadOnlyList<TEntity>> FindAsync(Expression<Func<TEntity, bool>> predicate, ...);
    Task<TEntity> AddAsync(TEntity entity, CancellationToken cancellationToken = default);
    Task UpdateAsync(TEntity entity, CancellationToken cancellationToken = default);
    Task DeleteAsync(TEntity entity, CancellationToken cancellationToken = default);
}

// 聚合根仓储接口（支持领域事件分发）
public interface IAggregateRepository<TAggregate, TId> : IRepository<TAggregate, TId>
{
    Task SaveAsync(TAggregate aggregate, CancellationToken cancellationToken = default);
}

依赖注入

services.AddSingleton<IEventBus, InMemoryEventBus>();
services.AddSingleton<IDomainEventDispatcher, DomainEventDispatcher>();

// 注册事件处理器
services.AddTransient<IEventHandler<PlayerCreatedEvent>, PlayerCreatedHandler>();

目录结构

T2FGame.Core/
├── DDD/
│   ├── Entity.cs                 # 实体基类
│   ├── AggregateRoot.cs          # 聚合根基类
│   ├── ValueObject.cs            # 值对象基类
│   ├── IRepository.cs            # 仓储接口
│   ├── IDomainEventDispatcher.cs # 领域事件分发器接口
│   └── DomainEventDispatcher.cs  # 领域事件分发器实现
├── Events/
│   ├── IDomainEvent.cs           # 领域事件接口
│   ├── IEventBus.cs              # 事件总线接口
│   ├── IEventHandler.cs          # 事件处理器接口
│   └── InMemoryEventBus.cs       # 内存事件总线实现
└── Results/
    ├── Result.cs                 # Result 类型
    ├── Error.cs                  # 错误类型
    └── ResultExtensions.cs       # 扩展方法