将依赖项注入IErrorHandler实现

Question

我正在实现IErrorHandler,以便在一个地方集中我的WCF服务的所有错误处理.这很好用:

public class ServiceErrorHandler : IErrorHandler
{

    public bool HandleError(Exception error)
    {
        // ..Log..
    }

    public void ProvideFault(Exception error, MessageVersion version, ref Message fault)
    {
        // ..Provide fault..
    }

}

现在,我们使用Ninject在服务的其余部分注入依赖项,我想在这里做同样的事情.由于WCF正在根据我的配置构建对象,并且我认为我没有任何钩子进入此过程,我需要使用属性注入:

    [Inject]
    public ILoggingService Logger { get; set; }

然而,这似乎永远不会被注入.我尝试使用Ninject的MVC扩展来设置ServiceErrorHandler允许像过滤器一样注入,但这似乎没有成功.有没有办法让这种情况发生？

Answer 1

迟到的回答,但你可以依赖注入IErrorHandler通过创建自定义ServiceHost,让我们说TestServiceHost.

在TestServiceHost你需要做的事情:

1. 用IErrorHandler参数实现构造函数.
2. 在里面,创建一个名为ErrorHandlerBehaviour*的私有嵌套类,它需要实现IServiceBehavior和IErrorHandler.它还必须具有带IErrorHandler参数的构造函数.
3. 覆盖OnStarting()方法,您将添加ErrorHandlerBehaviour到服务行为.必须先添加所有行为base.OnStarting().

*这个想法来自Juval Lowy的书中的例子 - "编程WCF服务".有关可在此处找到的故障和错误扩展的更多信息.

这是工作主机控制台应用程序.我不在那里使用IoC,只使用Pure DI,但您可以轻松地使用您想要的任何IoC解析记录器:

using System;
using System.Collections.ObjectModel;
using System.ServiceModel;
using System.ServiceModel.Channels;
using System.ServiceModel.Description;
using System.ServiceModel.Dispatcher;

namespace ConsoleHost
{
    class Program
    {
        static void Main(string[] args)
        {
            var logger = new DummyLogger();
            var errorHandler = new TestErrorHandler(logger);

            ServiceHost host = new TestServiceHost(errorHandler, typeof(TestService), new Uri("net.tcp://localhost:8002"));
            host.Open();

            Console.WriteLine("Press enter to exit");
            Console.ReadKey();
        }
    }

    [ServiceContract]
    public interface ITestService
    {
        [OperationContract]
        string Test(int input);
    }

    public class TestService : ITestService
    {
        public string Test(int input)
        {
            throw new Exception("Test exception!");
        }
    }

    public class TestErrorHandler : IErrorHandler
    {
        private ILogger Logger { get; }

        public TestErrorHandler(ILogger logger)
        {
            Logger = logger;
        }

        public bool HandleError(Exception error)
        {
            Logger.Log(error.Message);
            return true;
        }

        public void ProvideFault(Exception error, MessageVersion version, ref Message fault)
        {
            FaultException fe = new FaultException();
            MessageFault message = fe.CreateMessageFault();
            fault = Message.CreateMessage(version, message, null);
        }
    }

    public class TestServiceHost : ServiceHost
    {
        private readonly IErrorHandler errorHandler;

        public TestServiceHost(IErrorHandler errorHandler, Type serviceType, params Uri[] baseAddresses)
            : base(serviceType, baseAddresses)
        {
            this.errorHandler = errorHandler;
        }

        protected override void OnOpening()
        {
            Description.Behaviors.Add(new ErrorHandlerBehaviour(errorHandler));
            base.OnOpening();
        }

        class ErrorHandlerBehaviour : IServiceBehavior, IErrorHandler
        {
            private readonly IErrorHandler errorHandler;

            public ErrorHandlerBehaviour(IErrorHandler errorHandler)
            {
                this.errorHandler = errorHandler;
            }

            bool IErrorHandler.HandleError(Exception error)
            {
                return errorHandler.HandleError(error);
            }

            void IErrorHandler.ProvideFault(Exception error, MessageVersion version, ref Message fault)
            {
                errorHandler.ProvideFault(error, version, ref fault);
            }

            void IServiceBehavior.ApplyDispatchBehavior(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase)
            {
                foreach (ChannelDispatcher channelDispatcher in serviceHostBase.ChannelDispatchers)
                {
                    channelDispatcher.ErrorHandlers.Add(this);
                }
            }

            void IServiceBehavior.AddBindingParameters(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase, Collection<ServiceEndpoint> endpoints, BindingParameterCollection bindingParameters)
            {
            }

            void IServiceBehavior.Validate(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase)
            {
            }
        }
    }

    // Dummy logger
    public interface ILogger
    {
        void Log(string input);
    }

    public class DummyLogger : ILogger
    {
        public void Log(string input) => Console.WriteLine(input);
    }
}

和配置:

<system.serviceModel>
  <services>
    <service name="ConsoleHost.TestService">
      <endpoint address="net.tcp://localhost:8002/TestService"
                binding="netTcpBinding"
                contract="ConsoleHost.ITestService" />
    </service>
  </services>
</system.serviceModel>

顺便说一句.确保您已添加System.Runtime.Serialization到参考文献中