SimpleInjector.ActivationException 在 SignalrR 上使用简单注入器

Question

我在 Using Simple Injector with SignalR and my services are successfully resolved, not until OnDisconnected is called on the Hub class. Then I had to follow this question 上实现了答案作为解决方法，但每当请求集线器实例时都会出现异常。

我得到异常说：

[SimpleInjector.ActivationException] The registered delegate for type ChatHub threw an exception. The ChatHub is registered as 'Hybrid Web Request / Execution Context Scope' lifestyle, but the instance is requested outside the context of a Hybrid Web Request / Execution Context Scope.

堆栈跟踪：

at SimpleInjector.InstanceProducer.GetInstance()
at SimpleInjector.Container.GetInstance(Type serviceType)
at QuickChat.Hubs.SimpleInjectorHubActivator.Create(HubDescriptor descriptor) in c:\Users\Peter\Documents\Visual Studio 2013\Projects\QuickChat\QuickChat\Hubs\SimpleInjectorHubActivator.cs:line 21
at Microsoft.AspNet.SignalR.Hubs.DefaultHubManager.ResolveHub(String hubName)
at Microsoft.AspNet.SignalR.Hubs.HubDispatcher.CreateHub(IRequest request, HubDescriptor descriptor, String connectionId, StateChangeTracker tracker, Boolean throwIfFailedToCreate)

InnerException: 

at SimpleInjector.Scope.GetScopelessInstance[TService,TImplementation](ScopedRegistration`2 registration)
at SimpleInjector.Scope.GetInstance[TService,TImplementation](ScopedRegistration`2 registration, Scope scope)
at SimpleInjector.Advanced.Internal.LazyScopedRegistration`2.GetInstance(Scope scope)
at lambda_method(Closure )
at SimpleInjector.InstanceProducer.GetInstance()

查看下面我当前的代码配置。 集线器激活器：

public class SimpleInjectorHubActivator : IHubActivator
{
    private readonly Container _container;

    public SimpleInjectorHubActivator(Container container)
    {
        _container = container;
    }

    public IHub Create(HubDescriptor descriptor)
    {
        return (IHub)_container.GetInstance(descriptor.HubType);
    }
}

SimpleInjector 服务注册：

public class SimpleInjectorConfig
{
    public static void Register()
    {
        // Create the container as usual.
        var container = new Container();

        var hybrid = Lifestyle.CreateHybrid(
            () => container.GetCurrentExecutionContextScope() != null,
            new SimpleInjector.Integration.Web.WebRequestLifestyle(),
            new ExecutionContextScopeLifestyle());

        // Register types:
        container.RegisterSingle<MembershipRebootConfiguration>(MembershipRebootConfig.Create);
        container.Register<DefaultMembershipRebootDatabase>(() => new CustomMembershipRebootDatabase());
        container.Register<UserAccountService>(() => new UserAccountService(container.GetInstance<MembershipRebootConfiguration>(), container.GetInstance<IUserAccountRepository>()));
        container.Register<AuthenticationService, SamAuthenticationService>();
        container.RegisterPerWebRequest<IUserAccountQuery, DefaultUserAccountRepository>();
        container.RegisterPerWebRequest<IUserAccountRepository, DefaultUserAccountRepository>();

        container.Register(() => new DataAccess.EF.DataContext(), hybrid);
        container.Register<IUnitOfWork, UnitOfWork>(hybrid);
        container.Register<IUserService, UserService>(hybrid);

        //Register SimpleAuthentication callback provider class
        container.RegisterPerWebRequest<IAuthenticationCallbackProvider, SimpleAuthenticationProviderController>();
        //Register SimpleAuthentication MVC controller.
        container.RegisterPerWebRequest<SimpleAuthenticationController>(
            () => new SimpleAuthenticationController(container.GetInstance<IAuthenticationCallbackProvider>(), null));

        // This is an extension method from the integration package.
        container.RegisterMvcControllers(Assembly.GetExecutingAssembly());
        // This is an extension method from the integration package as well.
        container.RegisterMvcIntegratedFilterProvider();
        //Enable injections to SignalR Hubs
        var activator = new SimpleInjectorHubActivator(container);
        container.Register<ChatHub, ChatHub>(hybrid);
        GlobalHost.DependencyResolver.Register(typeof(IHubActivator), () => activator);

        container.Verify();
        //Set dependency resolver for MVC
        DependencyResolver.SetResolver(new SimpleInjectorDependencyResolver(container));
    }
}

Global.asax.cs:

protected void Application_Start()
    {
        SimpleInjectorConfig.Register();
        // Register the default hubs route: ~/signalr/hubs
        RouteTable.Routes.MapHubs();
        AreaRegistration.RegisterAllAreas();
        FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
        RouteConfig.RegisterRoutes(RouteTable.Routes);
        BundleConfig.RegisterBundles(BundleTable.Bundles);

        AntiForgeryConfig.UniqueClaimTypeIdentifier = ClaimTypes.NameIdentifier;
    }

Answer 1

你的混合生活方式是错误的。你应该改变谓词：

var hybrid = Lifestyle.CreateHybrid(
    () => container.GetCurrentExecutionContextScope() != null,
    new ExecutionContextScopeLifestyle(),
    new SimpleInjector.Integration.Web.WebRequestLifestyle());

提示：与其在整个组合根中重复使用该 hybrid 变量，还可以将其设置为默认作用域生活方式，如下所示：

container.Options.DefaultScopedLifestyle = hybrid;

通过这种方式，您可以将注册更改为以下内容：

container.Register<ChatHub, ChatHub>(Lifestyle.Scoped);

这使您的注册更容易、更清晰。

Answer 2

正如史蒂文在他的回答中所说，我的混合生活方式是错误的。我不得不改变谓词：

var hybrid = Lifestyle.CreateHybrid(
() => container.GetCurrentExecutionContextScope() != null,
new ExecutionContextScopeLifestyle(),
new SimpleInjector.Integration.Web.WebRequestLifestyle());

在与 Steven GitHub 讨论了几次之后，我得出了一个结论。

我必须将我的 ChatHub 变成 Humble Object 并从中提取所有逻辑并放入一个单独的 class 中，该 class 实现一个服务接口，该接口由公开所有逻辑的方法组成最初包含在 ChatHub

public interface IChatService
{
    void OnConnected(Guid userId, string connectionId, HubConnectionContext clients);
    void OnDisconnected(Guid userId, string connectionId);
    void Broadcast(string message, string username, HubConnectionContext clients);
}

public class ChatService : IChatService
{
    private readonly IUnitOfWork _unitOfWork;
    public UserChatService(IUnitOfWork unitOfWork) {
        _unitOfWork = unitOfWork;
    }

    public void OnConnected(Guid userId, string connectionId, HubConnectionContext clients) { 
        //Perform other operation using _unitOfWork
    }
    public void OnDisconnected(Guid userId, string connectionId) {
        //Perform other operation using _unitOfWork
    }
    public void Broadcast(string message, string username, HubConnectionContext clients) { 
        //Perform other operation using _unitOfWork and HubConnectionContext
        //broadcast message to other connected clients
        clients.others.broadcast(message);
    }
}

HubConnectionContext 对我来说真的像是运行时数据，所以我决定将它作为参数传递给方法。

有了这个，我的集线器 ChatHub 看起来很轻量级，将调用委托给 ChatService 对象，并且在调用集线器的 OnDisconnected() 时我不再遇到错误。

并且不要忘记在容器中注册您的服务：

container.Register<IChatService, ChatService>(hybrid);