请求范围已经被处理

本文关键字：处理 范围 请求 | 更新日期: 2023-09-27 18:11:29

我在MVC 3应用程序中使用Ninject和扩展EventBroker和DependencyCreation。我已经安装并正在使用Ninject。MVC3包，因此OnePerRequestModule。

我正在尝试将一个名为IParentService的服务注入控制器。IParentService依赖于ChildService，通过DependencyCreation扩展创建(没有硬引用)。

两个服务都注册在本地事件代理实例上(本地到ParentService)。

我希望IParentService对每个请求都有作用域，我希望依赖关系和事件代理与IParentService同时被处理，但是，我得到了ScopeDisposedException。我做错了什么?

一些代码:

服务定义:

public interface IParentService
{
}
public class ParentService : IParentService
{
    [EventPublication("topic://ParentService/MyEvent")]
    public event EventHandler<EventArgs> MyEvent;
}
public class ChildService
{
    [EventSubscription("topic://ParentService/MyEvent", typeof(bbv.Common.EventBroker.Handlers.Publisher))]
    public void OnMyEvent(object sender, EventArgs eventArgs)
    {            
    }
}

内核注册(NinjectWebCommon)

    private static void RegisterServices(IKernel kernel)
    {
        kernel.Bind<IParentService>().To<ParentService>()
            .InRequestScope()
            .OwnsEventBroker("ParentServiceBroker")
            .RegisterOnEventBroker("ParentServiceBroker");
        kernel.DefineDependency<IParentService, ChildService>();
        kernel.Bind<ChildService>().ToSelf()
            .WhenInjectedInto<ParentService>()
            .InDependencyCreatorScope()
            .RegisterOnEventBroker("ParentServiceBroker");            
    }

堆栈跟踪:

[ScopeDisposedException: The requested scope has already been disposed.]
   Ninject.Extensions.NamedScope.NamedScopeExtensionMethods.GetScope(IContext context, String scopeParameterName) in c:'Projects'Ninject'ninject.extensions.namedscope'src'Ninject.Extensions.NamedScope'NamedScopeExtensionMethods.cs:118
   Ninject.Extensions.NamedScope.NamedScopeExtensionMethods.GetScope(IContext context, String scopeParameterName) in c:'Projects'Ninject'ninject.extensions.namedscope'src'Ninject.Extensions.NamedScope'NamedScopeExtensionMethods.cs:126
   Ninject.Extensions.NamedScope.<>c__DisplayClass1`1.<InNamedScope>b__0(IContext context) in c:'Projects'Ninject'ninject.extensions.namedscope'src'Ninject.Extensions.NamedScope'NamedScopeExtensionMethods.cs:40
   Ninject.Planning.Bindings.BindingConfiguration.GetScope(IContext context) in c:'Projects'Ninject'ninject'src'Ninject'Planning'Bindings'BindingConfiguration.cs:119
   Ninject.Planning.Bindings.Binding.GetScope(IContext context) in c:'Projects'Ninject'ninject'src'Ninject'Planning'Bindings'Binding.cs:224
   Ninject.Activation.Context.GetScope() in c:'Projects'Ninject'ninject'src'Ninject'Activation'Context.cs:123
   Ninject.Activation.Caching.Cache.TryGet(IContext context) in c:'Projects'Ninject'ninject'src'Ninject'Activation'Caching'Cache.cs:110
   Ninject.Activation.Context.Resolve() in c:'Projects'Ninject'ninject'src'Ninject'Activation'Context.cs:150
   Ninject.<>c__DisplayClass10.<Resolve>b__c(IBinding binding) in c:'Projects'Ninject'ninject'src'Ninject'KernelBase.cs:386
   System.Linq.WhereSelectEnumerableIterator`2.MoveNext() +145
   System.Linq.<CastIterator>d__b1`1.MoveNext() +85
   System.Linq.Enumerable.Single(IEnumerable`1 source) +191
   Ninject.ResolutionExtensions.Get(IResolutionRoot root, String name, IParameter[] parameters) in c:'Projects'Ninject'ninject'src'Ninject'Syntax'ResolutionExtensions.cs:50
   Ninject.Extensions.ContextPreservation.ContextPreservationExtensionMethods.ContextPreservingGet(IContext context, String name, IParameter[] parameters) in c:'Projects'Ninject'ninject.extensions.contextpreservation'src'Ninject.Extensions.ContextPreservation'ContextPreservationExtensionMethods.cs:56
   Ninject.Extensions.bbvEventBroker.<>c__DisplayClass2`1.<RegisterOnEventBroker>b__0(IContext ctx, T instance) in c:'Projects'Ninject'ninject.extensions.bbveventbroker'src'Ninject.Extensions.bbvEventBroker'EventBrokerExtensionMethods.cs:45
   Ninject.Planning.Bindings.<>c__DisplayClass29`1.<OnDeactivation>b__28(IContext context, Object instance) in c:'Projects'Ninject'ninject'src'Ninject'Planning'Bindings'BindingConfigurationBuilder.cs:513
   Ninject.Activation.Strategies.<>c__DisplayClass4.<Deactivate>b__3(Action`2 action) in c:'Projects'Ninject'ninject'src'Ninject'Activation'Strategies'BindingActionStrategy.cs:42
   Ninject.Infrastructure.Language.ExtensionsForIEnumerableOfT.Map(IEnumerable`1 series, Action`1 action) in c:'Projects'Ninject'ninject'src'Ninject'Infrastructure'Language'ExtensionsForIEnumerableOfT.cs:32
   Ninject.Activation.Strategies.BindingActionStrategy.Deactivate(IContext context, InstanceReference reference) in c:'Projects'Ninject'ninject'src'Ninject'Activation'Strategies'BindingActionStrategy.cs:42
   Ninject.Activation.<>c__DisplayClass6.<Deactivate>b__4(IActivationStrategy s) in c:'Projects'Ninject'ninject'src'Ninject'Activation'Pipeline.cs:72
   Ninject.Infrastructure.Language.ExtensionsForIEnumerableOfT.Map(IEnumerable`1 series, Action`1 action) in c:'Projects'Ninject'ninject'src'Ninject'Infrastructure'Language'ExtensionsForIEnumerableOfT.cs:32
   Ninject.Activation.Pipeline.Deactivate(IContext context, InstanceReference reference) in c:'Projects'Ninject'ninject'src'Ninject'Activation'Pipeline.cs:72
   Ninject.Activation.Caching.Cache.Forget(CacheEntry entry) in c:'Projects'Ninject'ninject'src'Ninject'Activation'Caching'Cache.cs:253
   Ninject.Activation.Caching.Cache.Forget(IEnumerable`1 cacheEntries) in c:'Projects'Ninject'ninject'src'Ninject'Activation'Caching'Cache.cs:242
   Ninject.Activation.Caching.Cache.Clear(Object scope) in c:'Projects'Ninject'ninject'src'Ninject'Activation'Caching'Cache.cs:197
   Ninject.Web.Common.<>c__DisplayClass2.<DeactivateInstancesForCurrentHttpRequest>b__1(IKernel kernel) in c:'Projects'Ninject'Ninject.Web.Common'src'Ninject.Web.Common'OnePerRequestHttpModule.cs:74
   Ninject.GlobalKernelRegistration.MapKernels(Action`1 action) in c:'Projects'Ninject'ninject'src'Ninject'GlobalKernelRegistration.cs:75
   Ninject.Web.Common.OnePerRequestHttpModule.DeactivateInstancesForCurrentHttpRequest() in c:'Projects'Ninject'Ninject.Web.Common'src'Ninject.Web.Common'OnePerRequestHttpModule.cs:74
   Ninject.Web.Common.OnePerRequestHttpModule.<Init>b__0(Object o, EventArgs e) in c:'Projects'Ninject'Ninject.Web.Common'src'Ninject.Web.Common'OnePerRequestHttpModule.cs:56
   System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +136
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +69

EDIT - MORE DETAILS

该错误在RegisterOnEventBroker调用中设置的去激活委托中抛出，其中代码试图取消注册在事件代理上注册的任何对象。失败的原因是事件代理范围已被处置，可能是因为父服务已被处置。据我所知，Ninject只会调用OnDeactivation委托的对象与生命周期以外的瞬态作用域，所以为什么这不起作用，当父服务在RequestScope中注册让我困惑。暂态作用域对于父服务是不够的，因为我遇到了内存泄漏，因为这个问题。

我开始怀疑这是否是EventBroker扩展中的一个错误。

请求范围已经被处理

您必须首先将IParentService绑定到ParentService，然后使用具体类型kernel.Bind<ParentService>().ToSelf()的自绑定来定义对象范围和事件代理。

    private static void RegisterServices(IKernel kernel)
    {
        kernel.Bind<IParentService>().To<ParentService>();

        kernel.Bind<ParentService>().ToSelf()
       .InRequestScope()
       .OwnsEventBroker("ParentServiceBroker")
       .RegisterOnEventBroker("ParentServiceBroker");
        kernel.DefineDependency<IParentService, ChildService>();
        kernel.Bind<ChildService>().ToSelf()
            .WhenInjectedInto<ParentService>()
            .InDependencyCreatorScope()
            .RegisterOnEventBroker("ParentServiceBroker"); 
    }

编辑:如果你要解析的类型是一个具体类型(如上面的ParentService)， Ninject将通过一种称为隐式自绑定的机制自动创建一个默认关联。这样的:

 kernel.Bind<ParentService>().ToSelf();

另一方面，隐式自绑定是在默认的对象范围Transient中生成的。这就是为什么你的代码不能在Request范围内运行。

更多信息见此处

编辑2:

在Request范围内bbvEventBroker扩展中有一个bug，导致EventBroker在处置在该EventBroker上注册的对象之前被处置。因此，在对象的OnDeactivation方法中没有EventBroker，它的Unregister可以被调用，ScopeDisposedException可以被抛出。

    public static IBindingOnSyntax<T> OwnsEventBroker<T>(this IBindingOnSyntax<T> syntax, string eventBrokerName)
    {
        string namedScopeName = "EventBrokerScope" + eventBrokerName;
        syntax.DefinesNamedScope(namedScopeName);
        syntax.Kernel.Bind<IEventBroker>().To<EventBroker>().InNamedScope(namedScopeName).Named(eventBrokerName);
        syntax.Kernel.Bind<IEventBroker>().ToMethod(ctx => ctx.ContextPreservingGet<IEventBroker>(eventBrokerName)).WhenTargetNamed(eventBrokerName);
        return syntax;
    }

你可以在OwnsEventBroker方法中看到NamedScope在对象(ParentService)的作用域中定义，强制它在对象(ParentService)之前进行dispose。

另一方面，在对象(ParentService)的OnDeactivation中，需要先前处置的EventBroker。

    public static IBindingOnSyntax<T> RegisterOnEventBroker<T>(
        this IBindingOnSyntax<T> syntax, string eventBrokerName)
    {
        return
            syntax.OnActivation((ctx, instance) => ctx.ContextPreservingGet<IEventBroker>(eventBrokerName).Register(instance))
                  .OnDeactivation((ctx, instance) => ctx.ContextPreservingGet<IEventBroker>(eventBrokerName).Unregister(instance));
    }

EventBrokerExtensionMethods.cs

解决方案是使用NamedScope创建对象树。在Request作用域中定义父作用域，同时为其子作用域(Publisher/Subscriber)定义NamedScope，并拥有事件代理(OwnsEventBroker)。然后在父节点定义的命名范围中定义发布者(ChildService1)和订阅者(ChildService2)。通过这种方式，您可以确保事件代理的所有者将在其子事件之后被处置。

Ninject core当前在取消激活对象本身之前取消激活对象范围内的对象。

改变顺序似乎可以解决这个问题。尽管在进行更改之前，我必须检查这对其他情况可能产生的副作用

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