IMessageSink Interface

Definition

Namespace:

System.Runtime.Remoting.Messaging

Assembly:

mscorlib.dll

Defines the interface for a message sink.

C#

[System.Runtime.InteropServices.ComVisible(true)]
public interface IMessageSink

Derived

System.Runtime.Remoting.Channels.BinaryClientFormatterSink

System.Runtime.Remoting.Channels.IClientFormatterSink

System.Runtime.Remoting.Channels.SoapClientFormatterSink

System.Runtime.Remoting.Messaging.AsyncResult

Attributes

ComVisibleAttribute

Examples

The following code example shows the implementation of the IMessageSink interface. Note that the sample assumes type definitions and assembly references that must be provided for the sample to compile.

C#

using System;
using System.Collections;
using System.Threading;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels;
using System.Runtime.Remoting.Channels.Http;
using System.Runtime.Remoting.Proxies;
using System.Runtime.Remoting.Messaging;
using Share;	

namespace MyNameSpace
{

   public class MyProxy : RealProxy
   {
      string myUrl;
      string myObjectURI;
      IMessageSink myMessageSink;

      public MyProxy(Type myType, string myUrl1)
         : base(myType)
      {

         myUrl = myUrl1;

         IChannel[] myRegisteredChannels = ChannelServices.RegisteredChannels;
         foreach (IChannel channel in myRegisteredChannels )
         {
            if (channel is IChannelSender)
            {
               IChannelSender myChannelSender = (IChannelSender)channel;

               myMessageSink = myChannelSender.CreateMessageSink(myUrl, null, out myObjectURI);
               if (myMessageSink != null)
                  break;
            }
         }

         if (myMessageSink == null)
         {
            throw new Exception("A supported channel could not be found for myUrl1:"+ myUrl);
         }
      }

      public override IMessage Invoke(IMessage myMesg)
      {
         Console.WriteLine("MyProxy.Invoke Start");

         if (myMesg is IMethodCallMessage)
            Console.WriteLine("IMethodCallMessage");

         if (myMesg is IMethodReturnMessage)
            Console.WriteLine("IMethodReturnMessage");

         Console.WriteLine("Message Properties");
         IDictionary myDictionary = myMesg.Properties;
         IDictionaryEnumerator myEnum = (IDictionaryEnumerator) myDictionary.GetEnumerator();

         while (myEnum.MoveNext())
         {
            object myKey = myEnum.Key;
            string myKeyName = myKey.ToString();
            object myValue = myEnum.Value;

            Console.WriteLine("{0} : {1}", myKeyName, myEnum.Value);
            if (myKeyName == "__Args")
            {
               object[] myArgs = (object[])myValue;
               for (int myInt = 0; myInt < myArgs.Length; myInt++)
                  Console.WriteLine("arg: {0} myValue: {1}", myInt, myArgs[myInt]);
            }

            if ((myKeyName == "__MethodSignature") && (null != myValue))
            {
               object[] myArgs = (object[])myValue;
               for (int myInt = 0; myInt < myArgs.Length; myInt++)
                  Console.WriteLine("arg: {0} myValue: {1}", myInt, myArgs[myInt]);
            }
         }

         Console.WriteLine("myUrl1 {0} object URI{1}",myUrl,myObjectURI);

         myDictionary["__Uri"] = myUrl;
         Console.WriteLine("URI {0}", myDictionary["__URI"]);
         IMessage myRetMsg = myMessageSink.SyncProcessMessage(myMesg);

         if (myRetMsg is IMethodReturnMessage)
         {
            IMethodReturnMessage myMethodReturnMessage = (IMethodReturnMessage)myRetMsg;
         }

         Console.WriteLine("MyProxy.Invoke - Finish");
         return myRetMsg;
      }
   }

   //
   // Main class that drives the whole sample
   //
   public class ProxySample
   {
      public static void Main()
      {
         ChannelServices.RegisterChannel(new HttpChannel());

         Console.WriteLine("Remoting Sample:");

         Console.WriteLine("Generate a new MyProxy using the Type");
         Type myType = typeof(MyHelloService);
         string myUrl1 = "http://localhost/myServiceAccess.soap";
         MyProxy myProxy = new MyProxy(myType, myUrl1);

         Console.WriteLine("Obtain the transparent proxy from myProxy");
         MyHelloService myService = (MyHelloService)myProxy.GetTransparentProxy();

         Console.WriteLine("Calling the Proxy");
         string myReturnString = myService.myFunction("bill");

         Console.WriteLine("Checking result : {0}", myReturnString);

         if (myReturnString == "Hi there bill, you are using .NET Remoting")
         {
            Console.WriteLine("myService.HelloMethod PASSED : returned {0}", myReturnString);
         }
         else
         {
            Console.WriteLine("myService.HelloMethod FAILED : returned {0}", myReturnString);
         }
      }
   }
}

Remarks

When a method call is made on the proxy, the remoting infrastructure provides the necessary support for passing the arguments to the actual object across the remoting boundaries, calling the actual object method with the arguments, and returning the results back to the client of the proxy object.

A remote method call is a message that goes from the client end to the server end and possibly back again. As it crosses remoting boundaries on the way, the remote method call passes through a chain of IMessageSink objects. Each sink in the chain receives the message object, performs a specific operation, and delegates to the next sink in the chain. The proxy object contains a reference to the first IMessageSink it needs to use to start off the chain.

For asynchronous calls, at the time of delegation, each sink provides a reply sink (another IMessageSink) that will be called by the next sink when the reply is on its way back.

Different types of sinks perform different operations, depending on the type of message object received. For example, one sink could cause a lock to be taken, another could enforce call security, another could perform flow call control and reliability services, and yet another could transport the call to a different AppDomain, process, or computer. Two or more message sinks in the chain can interact with each other in regard to each specific action.

Notes to Implementers

It is important to note that code implementing the current interface must provide implementations for both SyncProcessMessage(IMessage) and AsyncProcessMessage(IMessage, IMessageSink), since synchronous calls can be converted to asynchronous calls and vice versa. Both methods must be implemented, even if the sink does not support asynchronous processing.

Properties

NextSink

Gets the next message sink in the sink chain.

Methods

AsyncProcessMessage(IMessage, IMessageSink)	Asynchronously processes the given message.
SyncProcessMessage(IMessage)	Synchronously processes the given message.

Applies to