Shared information between a MessageInspector and a web-service

Question

I have a question regarding sharing information between a MessageInspector and a web-service.

I have an identifier (Guid) that I use to "bind" AfterReceiveRequest and BeforeSendReply. It works fine. But I would like this identifier to be available also in the methods used in the web-service. This is very useful e.g. for tracking issues in a log.

Below is a small demo example to illustrate the idea. My problem is to find a solution there can get access to the return object from the method AfterReceiveRequest. In the line with "MagicStuff".

namespace Demo.MessageInspector
{
    public class DemoMessageInspector : IDispatchMessageInspector
    {
        public object AfterReceiveRequest(ref Message request, IClientChannel channel, InstanceContext instanceContext)
        {
            Guid activityId = Guid.NewGuid();
            MyLog.Message("AfterReceiveRequest", activityId);
            return activityId;
        }

        public void BeforeSendReply(ref Message reply, object correlationState)
        {
            Guid activityId = (Guid)correlationState;
            MyLog.Message("BeforeSendReply", activityId);
        }
    }
}

namespace Demo.WebServices
{
    [ServiceBehavior]
    [MessageInterceptionServiceBehaviour]
    public class MyWebService : IMyWebService
    {
        public void MyWebServiceMethod()
        {
            Guid activityId = (Guid)MagicStuff; // <-- correlationState from AfterReceiveRequest

            bool success = DoSomthing();

            if (!success)
                MyLog.Message("Error happened in MyWebServiceMethod", activityId);
        }
    }
}

I would appreciate any kind of help or hints.

Answer 1

You can use the OperationContext.IncomingMessageProperties Property. Here's the usage in your scenario:

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.ServiceModel;
using System.ServiceModel.Channels;
using System.ServiceModel.Description;
using System.ServiceModel.Dispatcher;
using Demo.MessageInspector;
using Demo.Utilities;

namespace Demo.WebServices
{
    public class MyWebService : IMyWebService, IServiceBehavior
    {
        public void MyWebServiceMethod()
        {
            // get the activityId from the incoming message properties
            var activityIdProperty = OperationContext.Current.IncomingMessageProperties
                .FirstOrDefault(property => property.Key == Properties.ActivityId.ToString());

            // create an empty Guid
            Guid activityId = new Guid();
            if (activityIdProperty.Value != null)
            {
                // replace the empty Guid with the activityId
                activityId = (Guid)activityIdProperty.Value;
            }
            bool success = DoSomething();
            if (!success)
                MyLog.Message("Error happened in MyWebServiceMethod", activityId);
        }

        private bool DoSomething()
        {
            // TODO: implement
            return false;
        }

        public void AddBindingParameters(
          ServiceDescription serviceDescription,
          ServiceHostBase serviceHostBase,
          System.Collections.ObjectModel.Collection<ServiceEndpoint> endpoints,
          BindingParameterCollection bindingParameters
        )
        {
            return;
        }

        public void ApplyDispatchBehavior(ServiceDescription serviceDescription,
            ServiceHostBase serviceHostBase)
        {
            foreach (ChannelDispatcher chDisp in serviceHostBase.ChannelDispatchers)
            {
                foreach (EndpointDispatcher epDisp in chDisp.Endpoints)
                {
                    var messageInspector = new DemoMessageInspector();
                    epDisp.DispatchRuntime.MessageInspectors.Add(messageInspector);
                }
            }
        }

        public void Validate(ServiceDescription serviceDescription, 
            ServiceHostBase serviceHostBase)
        {
            // TODO: implement validation
            //throw new NotImplementedException();
        }
    }
}

namespace Demo.MessageInspector
{
    public class DemoMessageInspector : IDispatchMessageInspector
    {
        public object AfterReceiveRequest(ref Message request, 
            IClientChannel channel, InstanceContext instanceContext)
        {
            Guid activityId = Guid.NewGuid();

            // add the activityId to the incoming message properties
            OperationContext.Current.IncomingMessageProperties
                .Add(Properties.ActivityId.ToString(), activityId);

            MyLog.Message("AfterReceiveRequest", activityId);
            return activityId;
        }

        public void BeforeSendReply(ref Message reply, object correlationState)
        {
            Guid activityId = (Guid)correlationState;
            MyLog.Message("BeforeSendReply", activityId);
        }
    }
}

namespace Demo.Utilities
{
    public enum Properties
    {
        ActivityId
    }

    public class MyLog
    {
        internal static void Message(string p, Guid guid)
        {
            File.AppendAllText(@"C:\Temp\log.txt", 
                String.Format("{0} {1} {2}\r\n", DateTime.Now, p, guid));
        }
    }
}

[UPDATE]

Alternatively, you could use the CorrelationManager.ActivityId Property. To do so, first add the following to your config files (both client and server):

<system.diagnostics>
  <sources>
    <source name="System.ServiceModel" propagateActivity="true">
      <listeners>
        <add name="ignored" type="System.Diagnostics.DefaultTraceListener" />
      </listeners>
    </source>
  </sources>
</system.diagnostics>

Then, add the following method in a Demo.Utilities.Helper class:

namespace Demo.Utilities
{
    internal class Helper
    {
        internal static Guid GetCorrelationId()
        {
            var headerPosition = OperationContext.Current.IncomingMessageHeaders.FindHeader("ActivityId",
                "http://schemas.microsoft.com/2004/09/ServiceModel/Diagnostics");
            if (headerPosition > -1)
            {
                var activityIdHeader = OperationContext.Current.IncomingMessageHeaders
                    .GetReaderAtHeader(headerPosition);
                var activityIdAttribute = activityIdHeader.GetAttribute("CorrelationId");
                return Guid.Parse(activityIdAttribute);
            }
            else
            {
                return Guid.Empty;
            }
        }
    }
}

Now you can use the method like this in the DemoMessageInspector:

public object AfterReceiveRequest(ref Message request,
    IClientChannel channel, InstanceContext instanceContext)
{
    var correlationId = Helper.GetCorrelationId();
    MyLog.Message("AfterReceiveRequest\tCorrelationId", correlationId);
    // ...
}

and like this in your service's method:

public void MyWebServiceMethod()
{
    var correlationId = Helper.GetCorrelationId();
    MyLog.Message("MyWebServiceMethod\tCorrelationId", correlationId);

    // ...
}