c# - 使用 Autofac 将对象注入(inject) MassTransit Saga

Question

我试图让 autofac 在创建时将工厂注入(inject)到 saga 中，但我无法让它工作。我在将工厂注入(inject)消费者时没有遇到任何问题，所以我知道它已正确注册，所以我假设我没有正确注册 sagas 并且 autofac 没有构建它们。

这是我的注册码:

var mapTypes = assembly.GetTypes()
   .Where(type => type.Implements(typeof(SagaClassMapping<>)));

builder.Register(context => GetSessionFactory(mapTypes)).AsSelf().SingleInstance();

// register all sagas and consumers
builder.RegisterAssemblyTypes(assembly)
   .Where(type => type.IsAssignableTo<ISaga>() || type.IsAssignableTo<IConsumer>())
   .AsSelf();

builder
    .RegisterGeneric(typeof(NHibernateSagaRepository<>))
    .As(typeof(ISagaRepository<>))
    .SingleInstance();

builder
    .Register(context => ServiceBusFactory.New(sbc =>
    {
        sbc.UseLog4Net();
        var queueUri = new Uri(ConfigurationManager.AppSettings["ReceiveQueue"]);
        var scope = context.Resolve<ILifetimeScope>();
        sbc.UseRabbitMq(transportConfig => 
            transportConfig.ConfigureHost(queueUri, hostConfig =>
            {
                hostConfig.SetUsername(ConfigurationManager.AppSettings["busUser"]);
                hostConfig.SetPassword(ConfigurationManager.AppSettings["busPassword"]);
            }));
        sbc.ReceiveFrom(queueUri);
        sbc.Subscribe(cfg => cfg.LoadFrom(scope));
    }))
    .SingleInstance();

传奇本身很标准

public class MySaga : SagaStateMachine<MySaga>, ISaga
{
    public Guid CorrelationId { get; private set; }
    public Func<MyObject> ObjectBuilder { get; set; }
    public MySaga() { }

    public MySaga(Guid correlationId)
    {
        CorrelationId = correlationId;
    }

    Static MySaga()
    {
        Define(() =>
        { .... }
    }

我试过添加 Func<MyObject>到构造函数，但它没有被击中，它确实在消费者中工作所以我知道 Autofac 可以构建一个 Func<MyObject> .我也尝试过使用属性注入(inject)，但没有成功:

builder.RegisterAssemblyTypes(assembly)
   .Where(type => type.IsAssignableTo<ISaga>() || type.IsAssignableTo<IConsumer>())
   .PropertiesAutowired()
   .AsSelf();

和

builder.RegisterType<MySaga>()
    .OnActivated(arg => arg.Instance.MyBuilder =
        arg.Context.Resolve<Func<MyObject>>())
    .AsSelf();

对于我做错的任何帮助，我们将不胜感激。

---

我在 masstransit-discuss group 上收到了 Chris Patterson 的回复这指出我可能做错了。

Automatonymous is a better choice if you have dependencies, since the state machine and the state itself are separate classes.

Injecting dependencies into a class hydrated via NHibernate is never going to end well. There are a couple of helper classes that can be used to perform property-injection into the saga after it is loaded from NHibernate, the decorating saga repository I think has been posted here.

Here is the example of the injecting repository for Magnum:https://github.com/MassTransit/MassTransit/blob/master/src/MassTransit.Tests/Saga/Injecting_Specs.cs

鉴于 NHibernate 正在为对象补水，我应该在那里寻找钩子(Hook)。我有解决当前问题的方法，但如果/当我找到答案时，我会在此处发布答案。

Answer 1

老问题，但我们花了一段时间才找到一种合适的方法来连接 sagas 和 autofac，然后在其上添加 nhibernate。

首先创建一个布线类(属性注入(inject))

public class MySagaRepository<TSaga> : ISagaRepository<TSaga> where TSaga : class, ISaga
    {
    private ISagaRepository<TSaga> _inner;
    private readonly IComponentContext _context;

    public MySagaRepository(ISagaRepository<TSaga> inner, IComponentContext context)
    {
        _inner = inner;
        _context = context;
    }

    public IEnumerable<Action<IConsumeContext<TMessage>>> GetSaga<TMessage>(IConsumeContext<TMessage> context, Guid sagaId, InstanceHandlerSelector<TSaga, TMessage> selector, ISagaPolicy<TSaga, TMessage> policy) where TMessage : class
    {
        return _inner.GetSaga(context, sagaId, (saga, message) =>
        {
            _context.InjectProperties(saga);
            return selector(saga, message);
        }, policy);
    }

    public IEnumerable<Guid> Find(ISagaFilter<TSaga> filter)
    {
        return _inner.Find(filter);
    }

    public IEnumerable<TSaga> Where(ISagaFilter<TSaga> filter)
    {
        return _inner.Where(filter).Select(x =>
        {
            _context.InjectProperties<TSaga>(x);
            return x;
        });
    }

    public IEnumerable<TResult> Where<TResult>(ISagaFilter<TSaga> filter, Func<TSaga, TResult> transformer)
    {
        return _inner.Where(filter, x =>
        {
            _context.InjectProperties(x);
            return transformer(x);
        });
    }

    public IEnumerable<TResult> Select<TResult>(Func<TSaga, TResult> transformer)
    {
        return _inner.Select(x =>
        {
            _context.InjectProperties(x);
            return transformer(x);
        });
    }
}

然后接线

builder.RegisterGeneric(typeof(NHibernateSagaRepository<>)).Named("innerRepo", typeof(ISagaRepository<>));
builder.RegisterGenericDecorator(typeof(MySagaRepository<>), typeof(ISagaRepository<>), fromKey: "innerRepo");

为了坚持，这只是一个问题

public class SagaPersistenceHandler
{
    public static ISessionFactory CreateSessionFactory()
    {
        var provider = new SqlServerSessionFactoryProvider(ConfigurationManager.ConnectionStrings["myConnectionString"].ConnectionString, new[]
        {
            typeof (MySagaMap)
        });

        return provider.GetSessionFactory();
    }
}

现在连线

builder.Register(c => SagaPersistenceHandler.CreateSessionFactory()).As<ISessionFactory>();

和 saga 映射到 saga(不包括在内)

public MySagaMap()
    {
        SchemaAction(NHibernate.Mapping.ByCode.SchemaAction.None);
        Table("dbo.[tTable]");
        Property(x => x.Id);
        Property(x => x.CloseDate);
    }
}

剩下的就是注册你的 saga

builder.RegisterType<MySaga>().AsSelf(); 

工作得很好(归功于@erikkallen)