WCF 跨多个客户端共享 IClientMessageInspector 实例

Question

当通过位于此处的标题“集中 cookie 管理”下概述的方法进行 WCF 服务调用时，我正在管理共享身份验证 cookie：http://megakemp.com/2009/02/06/managing-shared-cookies-in-wcf/

我已经设置了自定义的 IClientMessageInspector、IEndpointBehavior、BehaviorExtensionElement，有效。我的端点行为添加了一个消息检查器，如下所示：

public class MyEndpointBehavior : IEndpointBehavior
{
    public void AddBindingParameters(ServiceEndpoint endpoint, System.ServiceModel.Channels.BindingParameterCollection bindingParameters)
    {
    }
    public void ApplyClientBehavior(ServiceEndpoint endpoint, System.ServiceModel.Dispatcher.ClientRuntime clientRuntime)
    {
        // yuck.. Wish I had an instance of MyClientMessageInspector
        // (which has the auth cookie already) so I could just inject that
        // instance here instead of creating a new instance
        clientRuntime.MessageInspectors.Add(new MyClientMessageInspector());
    }
    public void ApplyDispatchBehavior(ServiceEndpoint endpoint, System.ServiceModel.Dispatcher.EndpointDispatcher endpointDispatcher)
    {
    }
    public void Validate(ServiceEndpoint endpoint)
    {
    }
}

一切都完美工作，但是当您想要在多个客户端上共享 cookie 时，此解决方案就会崩溃。由于 ApplyDispatchBehavior() 方法创建了一个新实例，因此任何其他客户端都无法获取该消息检查器实例，因此也无法获取身份验证票证。

因此，我想到尝试创建一个自定义构造函数，在其中可以注入实例，如下所示：

MyEndpointBehavior(MyClientMessageInspector msgInspector) { ... }

但是，WCF 需要无参数构造函数。通过互联网进行筛选，WCF 具有允许依赖项注入、创建 IInstanceProvider、IServiceBehavior 等的钩子。但我不认为这就是我在这里寻找的东西。

谁能帮助引导我走向正确的方向？

Answer 1

您只需扩展该概念，以便将 cookie 存储在消息检查器本身之外，以便消息检查器的所有实例共享相同的存储。

穷人的方法，只是开始，就是使用静态字段而不是实例字段。显然，如果您有多个线程，则需要在更新字段时提供并发性。从这里开始，如果您将其推断为 cookie 容器概念，然后确保与所有客户端共享同一个容器，您可以变得更加奇特。可以通过获取客户端通道的 ChannelParameterCollection 并向其添加属性来共享容器，然后您的行为在检查消息并从中提取 cookie 时查找该属性。这看起来有点像这样：

应用程序逻辑

// Hold onto a static cookie container
public static CookieContainer MyCookieContainer;

// When instantiating the client add the cookie container to the channel parameters
MyClient client = new MyClient();
client.InnerChannel.GetProperty<ChannelParameterCollection>().Add(MyCookieContainer);

消息检查器逻辑

public void BeforeSendMessage(ref Message, IClientChannel clientChannel)
{
    // Find the cookie container for the current channel
    CookieContainer cookieContainer = clientChannel.GetProperty<ChannelParameterCollection>().Select(p => p as CookieContainer).Where(cc => cc != null).First();

    // ... use the cookie container to set header on outgoing context ...
}

Answer 2

你是对的， IInstanceProvider 对你的情况没有帮助 - 它仅用于提供服务实例。您的行为不需要无参数构造函数。您需要配置元素的无参数构造函数，并且此类可以使用某些依赖项注入类（见下文）来创建行为所需的适当检查器类。

namespace ConsoleApplication4
{
    public class MyEndpointBehavior : IEndpointBehavior
    {
        IClientMessageInspector inspector;
        public MyEndpointBehavior(IClientMessageInspector inspector)
        {
            this.inspector = inspector;
        }

        public void AddBindingParameters(ServiceEndpoint endpoint, BindingParameterCollection bindingParameters)
        {
        }

        public void ApplyClientBehavior(ServiceEndpoint endpoint, ClientRuntime clientRuntime)
        {
            clientRuntime.MessageInspectors.Add(this.inspector);
        }

        public void ApplyDispatchBehavior(ServiceEndpoint endpoint, EndpointDispatcher endpointDispatcher)
        {
        }

        public void Validate(ServiceEndpoint endpoint)
        {
        }
    }
    public class MyEndpointBehaviorElement : BehaviorExtensionElement
    {
        public override Type BehaviorType
        {
            get { return typeof(MyEndpointBehavior); }
        }

        protected override object CreateBehavior()
        {
            return new MyEndpointBehavior(ClientInspectorFactory.GetClientInspector());
        }
    }
    public class MyClientInspector : IClientMessageInspector
    {
        public MyClientInspector()
        {
        }

        public void AfterReceiveReply(ref Message reply, object correlationState)
        {
            Console.WriteLine("AfterReceiveReply");
        }

        public object BeforeSendRequest(ref Message request, IClientChannel channel)
        {
            Console.WriteLine("BeforeSendRequest");
            return null;
        }
    }
    public static class ClientInspectorFactory
    {
        static IClientMessageInspector instance;
        public static IClientMessageInspector GetClientInspector()
        {
            if (instance == null)
            {
                instance = new MyClientInspector();
            }

            return instance;
        }
    }
    [ServiceContract]
    public interface ITest
    {
        [OperationContract]
        int Add(int x, int y);
    }
    public class Service : ITest
    {
        public int Add(int x, int y) { return x + y; }
    }
    class Program
    {
        static void Main(string[] args)
        {
            ServiceHost host = new ServiceHost(typeof(Service));
            host.Open();
            Console.WriteLine("Host opened");

            ChannelFactory<ITest> factory = new ChannelFactory<ITest>("client1");
            ITest proxy = factory.CreateChannel();
            Console.WriteLine(proxy.Add(3, 4));
            ((IClientChannel)proxy).Close();
            factory.Close();

            factory = new ChannelFactory<ITest>("client2");
            proxy = factory.CreateChannel();
            Console.WriteLine(proxy.Add(5, 8));
            ((IClientChannel)proxy).Close();
            factory.Close();

            host.Close();
        }
    }
}

Answer 3

我喜欢@carlosfigueira 和@drew 提供的答案，但我最终想出了一个稍微不同的方法。我选择以编程方式配置 IEndpointBehavior，而不是通过配置。让事情变得简单多了。我更改了端点行为以存储客户端消息检查器，如下所示：

public class MyEndpointBehavior : IEndpointBehavior
{
    private MyClientMessageInspector_myClientMessageInspector;

    public MyClientMessageInspector MyClientMessageInspector
    {
        get
        {
            if (_myClientMessageInspector == null)
            {
                _myClientMessageInspector = new MyClientMessageInspector();
            }
            return _myClientMessageInspector;
         }
    }
    public void AddBindingParameters(ServiceEndpoint endpoint, System.ServiceModel.Channels.BindingParameterCollection bindingParameters)
    {
    }
    public void ApplyClientBehavior(ServiceEndpoint endpoint, System.ServiceModel.Dispatcher.ClientRuntime clientRuntime)
    {
        clientRuntime.MessageInspectors.Add(MyClientMessageInspector);
    }
public void ApplyDispatchBehavior(ServiceEndpoint endpoint, System.ServiceModel.Dispatcher.EndpointDispatcher endpointDispatcher)
    {
    }
    public void Validate(ServiceEndpoint endpoint)
    {
    }
}

然后我只是在客户端之间共享此行为，如下所示：

var behavior = new MyEndpointBehavior();
client1.Endpoint.Behaviors.Add(behavior);
client2.Endpoint.Behaviors.Add(behavior);

现在两个客户端将共享相同的身份验证 cookie。