c# - 在 WCF 消息检查中，如何在消息对象中查找输入参数的值？

Question

在 WCF 消息检查中，如何在消息对象中查找输入参数的值？

我正在使用 MessageInspector 并具有以下类：

public class MyMessageInspector : IDispatchMessageInspector
{
    public object AfterReceiveRequest(ref Message request, IClientChannel channel, InstanceContext instanceContext)
    {
        // TODO: how to find the value of the siteName parameter if exists?

        Console.WriteLine("Incoming request: {0}", request);
        return null;
    }

    public void BeforeSendReply(ref Message reply, object correlationState)
    {

    }
}

如何提取我的 web 方法的 siteName 输入参数的值？我所有的 webmethods 都有 siteName 输入参数。

Answer 1

消息和参数之间的转换由消息格式化程序完成。您可以这样做，但是一旦您读取消息以获取参数的值，则该消息已被使用，因此您需要在将其传递给 WCF 之前重新创建它（这就是为什么在消息检查器中，请求被传递通过参考，所以如果你确实需要使用它，你可以更换它）。

正如@burning_LEGION 所提到的，参数检查器可能是您场景的最佳选择。在检查器本身上，它没有参数名称，但您可以从操作描述中获取它们，您的行为中有这些名称，您将使用它来添加参数检查器。下面的代码显示了如何完成它的一种方法。

public class StackOverflow_15637994
{
    [ServiceContract]
    public interface ITest
    {
        [OperationContract]
        string Echo(string text);
        [OperationContract]
        int Execute(string op, int x, int y);
        [OperationContract]
        bool InOutAndRefParameters(int x, ref int y, out int z);
    }
    public class Service : ITest
    {
        public string Echo(string text)
        {
            return text;
        }

        public int Execute(string op, int x, int y)
        {
            return x + y;
        }

        public bool InOutAndRefParameters(int x, ref int y, out int z)
        {
            z = y;
            y = x;
            return true;
        }
    }
    public class MyInspector : IParameterInspector
    {
        string[] inputParameterNames;
        string[] outputParameterNames;
        public MyInspector(string[] inputParameterNames, string[] outputParameterNames)
        {
            this.inputParameterNames = inputParameterNames;
            this.outputParameterNames = outputParameterNames;
        }

        public void AfterCall(string operationName, object[] outputs, object returnValue, object correlationState)
        {
            Console.WriteLine("Operation: {0}", operationName);
            Console.WriteLine("  Result: {0}", returnValue);
            for (int i = 0; i < outputs.Length; i++)
            {
                Console.WriteLine("  [out] {0}: {1}", this.outputParameterNames[i], outputs[i]);
            }
        }

        public object BeforeCall(string operationName, object[] inputs)
        {
            Console.WriteLine("Operation: {0}", operationName);
            for (int i = 0; i < inputs.Length; i++)
            {
                Console.WriteLine("  {0}: {1}", this.inputParameterNames[i], inputs[i]);
            }

            return null;
        }
    }
    public class MyBehavior : IEndpointBehavior
    {
        public void AddBindingParameters(ServiceEndpoint endpoint, BindingParameterCollection bindingParameters)
        {
        }

        public void ApplyClientBehavior(ServiceEndpoint endpoint, ClientRuntime clientRuntime)
        {
        }

        public void ApplyDispatchBehavior(ServiceEndpoint endpoint, EndpointDispatcher endpointDispatcher)
        {
            foreach (var operation in endpoint.Contract.Operations)
            {
                string[] inputParamNames = operation.Messages[0].Body.Parts
                    .OrderBy(mpd => mpd.Index)
                    .Select(mpd => mpd.Name)
                    .ToArray();
                string[] outputParamNames = null;
                if (operation.Messages.Count > 1)
                {
                    outputParamNames = operation.Messages[1].Body.Parts
                        .OrderBy(mpd => mpd.Index)
                        .Select(mpd => mpd.Name)
                        .ToArray();
                }

                MyInspector inspector = new MyInspector(inputParamNames, outputParamNames);
                endpointDispatcher.DispatchRuntime.Operations[operation.Name].ParameterInspectors.Add(inspector);
            }
        }

        public void Validate(ServiceEndpoint endpoint)
        {
        }
    }
    public static void Test()
    {
        string baseAddress = "http://" + Environment.MachineName + ":8000/Service";
        ServiceHost host = new ServiceHost(typeof(Service), new Uri(baseAddress));
        ServiceEndpoint endpoint = host.AddServiceEndpoint(typeof(ITest), new BasicHttpBinding(), "");
        endpoint.Behaviors.Add(new MyBehavior());
        host.Open();
        Console.WriteLine("Host opened");

        ChannelFactory<ITest> factory = new ChannelFactory<ITest>(new BasicHttpBinding(), new EndpointAddress(baseAddress));
        ITest proxy = factory.CreateChannel();

        proxy.Echo("Hello");
        proxy.Execute("foo", 2, 5);
        int z;
        int y = 2;
        proxy.InOutAndRefParameters(3, ref y, out z);

        ((IClientChannel)proxy).Close();
        factory.Close();

        Console.Write("Press ENTER to close the host");
        Console.ReadLine();
        host.Close();
    }
}

Answer 2

您可以反序列化Message和使用任何字段，但使用IParameterInspector更好