WCF 跨多个客户端共享 IClientMessageInspector 实例

Question

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

我已经设置了自定义IClientMessageInspector、IEndpointBehavior、BehaviorExtensionElement，作品。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)
    {
    }
}

这一切都完美地运行，但是当您想要在多个客户端上共享 cookie 时，此解决方案就会失效。因为ApplyDispatchBehavior() 方法创建了一个新实例，所以任何其他客户端都不会获得该消息检查器实例，因此也不会获得身份验证票。

然后我想尝试创建一个自定义构造函数，我可以像这样注入实例：

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 具有允许依赖注入、创建IInstanceProvider、IServiceBehavior 等的挂钩。但我认为这不是我要在这里寻找的。​​p>

谁能帮我指引正确的方向？

Answer 1

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我的 IEndpointBehavior，而不是通过配置。让事情变得简单多了。我更改了我的端点行为以存储我的客户端消息检查器，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)
    {
    }
}

然后我简单的在客户端之间分享了这个行为，如下：

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。

Answer 2

你是对的，IInstanceProvider 对你的情况没有帮助 - 它仅用于提供 service 实例。您的行为不需要无参数构造函数。您需要为 config 元素提供一个无参数构造函数，并且此类可以使用一些依赖注入类（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

您只需要扩展这个概念，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空间。

穷人的方法，刚开始，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。如果您将其推断为 cookie 容器概念，然后确保您与所有客户端共享同一个容器，那么您可以从那里变得更加出色。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，然后您的行为会在检查消息并从中提取 cookie 时查找该属性。看起来有点像这样：

应用逻辑

// 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 ...
}