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Remoting Example: Tracking Service

This topic is specific to a legacy technology that is retained for backward compatibility with existing applications and is not recommended for new development. Distributed applications should now be developed using the  Windows Communication Foundation (WCF).

The TrackingServices class provides for a general tracking service with pluggable tracking handlers. Methods on the ITrackingHandler interface are called under the following circumstances:

  • An ObjRef object has been generated (as the result of a marshal).

  • An ObjRef has been received (as the result of an unmarshal).

  • An object has been disconnected.

For more details, see TrackingServices and ITrackingHandler in the reference documentation.

3tzky0f2.Caution(en-us,VS.100).gifCaution:
.NET Framework remoting does not do authentication or encryption by default. Therefore, it is recommended that you take all necessary steps to make certain of the identity of clients or servers before interacting with them remotely. Because .NET Framework remoting applications require FullTrust permissions to execute, if a unauthorized client were granted access on your server, the client could execute code as though it were fully trusted. Always authenticate your endpoints and encrypt the communication streams, either by hosting your remoted types in Internet Information Services (IIS), or by building a custom channel sink pair to do this work.

To compile and run this sample

  1. Copy all files into one directory.

  2. Type the following commands at a command prompt:

    csc /t:library /r:System.Runtime.Remoting.dll TrackingHandler.cs
    csc /t:library /r:System.Runtime.Remoting.dll RemoteType.cs
    csc /r:RemoteType.dll /r:System.Runtime.Remoting.dll /r:TrackingHandler.dll server.cs
    csc /r:RemoteType.dll /r:System.Runtime.Remoting.dll client.cs
    
  3. Open two command prompts pointing to the same directory. In one, type server. In the other, type client.

This application runs on a single computer or across a network. If you want to run this application over a network, you must replace "localhost" in the client configuration with the name of the remote computer.

TrackingHandler

using System;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels;
using System.Runtime.Remoting.Services;

namespace TrackingHandler
{
    public class TrackingHandler : ITrackingHandler
    {
        // Notifies a handler that an object has been marshaled.
        public void MarshaledObject(Object obj, ObjRef objref)
        {
            Console.WriteLine("Tracking: An instance of {0} was marshaled. The instance HashCode is: {1}", obj.ToString(), obj.GetHashCode().ToString());
            Console.WriteLine("ObjRef dump:");
            if (objref.ChannelInfo != null)
            {
                Console.WriteLine("  -- ChannelInfo: ");
                DumpChannelInfo(objref.ChannelInfo);
            }
            if (objref.EnvoyInfo != null)
                Console.WriteLine("  -- EnvoyInfo: " + objref.EnvoyInfo.ToString());
            if (objref.TypeInfo != null)
            {
                Console.WriteLine("  -- TypeInfo: " + objref.TypeInfo.ToString());
                Console.WriteLine("      -- " + objref.TypeInfo.TypeName);
            }
            if (objref.URI != null)
                Console.WriteLine("  -- URI: " + objref.URI.ToString());
        }

        private void DumpChannelInfo(IChannelInfo info)
        {

            foreach (object obj in info.ChannelData)
            {
                if (obj is ChannelDataStore)
                {
                    foreach (string uri in ((ChannelDataStore)obj).ChannelUris)
                        Console.WriteLine("      -- ChannelUris:" + uri);
                }
            }
        }

        // Notifies a handler that an object has been unmarshaled.
        public void UnmarshaledObject(Object obj, ObjRef or)
        {
            Console.WriteLine("Tracking: An instance of {0} was unmarshaled. The instance HashCode is: {1}", obj.ToString(), obj.GetHashCode().ToString());
        }

        // Notifies a handler that an object has been disconnected.
        public void DisconnectedObject(Object obj)
        {
            Console.WriteLine("Tracking: An instance of {0} was disconnected. The instance HashCode is: {1}", 
                obj.ToString(), obj.GetHashCode().ToString());
        }
    }
}

RemoteType

using System;

namespace RemoteType
{
    public class ServiceClass : MarshalByRefObject
    {
        private DateTime starttime;

        public ServiceClass()
        {
            Console.WriteLine("A ServiceClass has been created.");
            starttime = DateTime.Now;
        }

        ~ServiceClass()
        {
            Console.WriteLine("ServiceClass being collected after " + (new TimeSpan(DateTime.Now.Ticks - starttime.Ticks)).ToString() + " seconds.");
        }

        public DateTime GetServerTime()
        {
            Console.WriteLine("Time requested by client.");
            return DateTime.Now;
        }
    }
}

Server

[Visual Basic]

Imports System
Imports System.Runtime.Remoting
Imports System.Runtime.Remoting.Channels
Imports System.Runtime.Remoting.Channels.Tcp
Imports System.Runtime.Remoting.Services
Imports TrackingHandler

Public Class Server
    Public Shared Sub Main()
        Dim channel As TcpChannel = New TcpChannel(8080)
        ChannelServices.RegisterChannel(channel, False)

        TrackingServices.RegisterTrackingHandler(New TrackingHandler())

        Dim service As ServiceClass = New ServiceClass()
        Dim obj As ObjRef = RemotingServices.Marshal(service, "TcpService")

        Console.WriteLine("Press Enter to unmarshal the object.")
        Console.ReadLine()

        RemotingServices.Unmarshal(obj)

        Console.WriteLine("Press Enter to disconnect the object.")
        Console.ReadLine()

        RemotingServices.Disconnect(service)
    End Sub
End Class

[C#]

using System;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels;
using System.Runtime.Remoting.Channels.Tcp;
using System.Runtime.Remoting.Services;
using TrackingHandler;
using RemoteType;

namespace Server
{
    public class Server
    {
        public static void Main(string[] Args)
        {
            TcpChannel channel = new TcpChannel(8080);
            ChannelServices.RegisterChannel(channel, false);

            TrackingServices.RegisterTrackingHandler(new TrackingHandler.TrackingHandler());

            ServiceClass service = new ServiceClass();
            ObjRef obj = RemotingServices.Marshal(service, "TcpService");

            Console.WriteLine("\r\nPress Enter to unmarshal the object.");
            Console.ReadLine();

            RemotingServices.Unmarshal(obj);

            Console.WriteLine("Press Enter to disconnect the object.");
            Console.ReadLine();

            RemotingServices.Disconnect(service);
        }
    }
}

Client

using System;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels;
using System.Runtime.Remoting.Channels.Tcp;
using RemoteType;

namespace Client
{
    public class ClientProcess
    {
        public static void Main(string[] Args)
        {
            ChannelServices.RegisterChannel(new TcpChannel(), false);

            WellKnownClientTypeEntry remotetype = new WellKnownClientTypeEntry(
                typeof(ServiceClass), 
                "tcp://localhost:8080/TcpService");
            RemotingConfiguration.RegisterWellKnownClientType(remotetype);

            ServiceClass service = new ServiceClass();
            Console.WriteLine("Server time is: " + service.GetServerTime().ToLongTimeString());
        }
    }
}

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