Remotingbeispiel: CallContext

In diesem Beispiel werden die CallContext-Klasse und die ILogicalThreadAffinative-Schnittstelle verwendet, um Daten zwischen einer Remoteclientanwendung und einer Remoteserveranwendung zu übergeben.

Diese Anwendung wird auf einem einzelnen Computer oder über ein Netzwerk ausgeführt. Wenn Sie diese Anwendung über ein Netzwerk ausführen möchten, müssen Sie "localhost" in der Clientkonfiguration durch den Namen des Remotecomputers ersetzen.

Vorsicht:

.NET-Remoting führt standardmäßig keine Authentifizierung oder Verschlüsselung durch. Daher empfiehlt es sich, vor der Remoteinteraktion mit Clients und Servern alle erforderlichen Schritte zu unternehmen, um die Identität der Clients oder Server sicherzustellen. Da .NET-Remoteanwendungen FullTrust-Berechtigungen zur Ausführung benötigen, könnte ein nicht autorisierter Client Code so ausführen, als ob er voll vertrauenswürdig wäre, wenn dem Client Zugriff auf Ihren Server gewährt würde. Authentifizieren Sie die Clients unbedingt, und verschlüsseln Sie die Kommunikationsstreams. Weitere Informationen finden Sie unter Sicherheit beim Remoting.

So kompilieren Sie dieses Beispiel

• Geben Sie an der Eingabeaufforderung folgende Befehle ein:

  [Visual Basic]

  vbc /r:System.Runtime.Remoting.dll /t:library MyRemoteType.vb
  vbc /r:System.Runtime.Remoting.dll /r:MyRemoteType.dll client.vb
  vbc /r:System.Runtime.Remoting.dll /r:MyRemoteType.dll server.vb
  

  [C#]

  csc /r:System.Runtime.Remoting.dll /t:library MyRemoteType.cs
  csc /r:System.Runtime.Remoting.dll /r:MyRemoteType.dll client.cs
  csc /r:System.Runtime.Remoting.dll /r:MyRemoteType.dll server.cs
  

MyRemoteType

Imports System
Imports System.Runtime.Remoting
Imports System.Runtime.Remoting.Messaging

Namespace [Shared]
    Public Class MyRemoteType
    Inherits MarshalByRefObject

    Private starttime As DateTime

    Public Sub New()
        Console.WriteLine("A MyRemoteObject instance has been created.")
        starttime = DateTime.Now
    End Sub

    Protected Overrides Sub Finalize()
        Console.WriteLine("MyRemoteObject being collected after " & (New TimeSpan(DateTime.Now.Ticks - starttime.Ticks)).ToString() & " seconds.")
    End Sub

    Public Function GetServerTime() As DateTime
        Console.WriteLine("Time requested by a client.")

        ' This call overwrites the client's CallContextString.
        CallContext.SetData("ServerThreadData", New CallContextString("This is the server side replacement."))
        Return DateTime.Now
    End Function
End Class

'  One method of communicating between client and server is 
'  to use the CallContext. Calling CallContext.SetData essentially puts the data
'  in a Thread Local Store. This means that the information is available 
'  to that thread or that "logical" thread (across application domains) only.
<Serializable()> _
Public Class CallContextString
    Implements ILogicalThreadAffinative

    Dim _str As String = ""

    Public Sub New(ByVal str As String)
        _str = str
        Console.WriteLine("CallContextString created.")
    End Sub

    Public Overrides Function ToString() As String
        Return _str
    End Function
End Class
End Namespace

using System;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Messaging;

namespace Shared
{
    public class MyRemoteType : MarshalByRefObject 
    {
        private DateTime starttime;

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

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

        public DateTime GetServerTime()
        {
            Console.WriteLine("Time requested by a client.");

            // This call overwrites the client's CallContextString.
            CallContext.SetData("ServerThreadData", new CallContextString("This is the server side replacement."));
            return DateTime.Now;
        }
    }

    //  One method of communicating between client and server is 
    //  to use the CallContext. Calling CallContext.SetData essentially puts the data
    //  in a Thread Local Store. This means that the information is available 
    //  to that thread or that "logical" thread (across application domains) only.
    [Serializable]
    public class CallContextString : ILogicalThreadAffinative
    {
        String _str = "";

        public CallContextString(String str)
        {
            _str = str;
            Console.WriteLine("CallContextString created.");
        }

        public override String ToString()
        {
            return _str;
        }
    }
}

Client

[Visual Basic]

Imports System
Imports System.Runtime.Remoting
Imports System.Runtime.Remoting.Channels
Imports System.Runtime.Remoting.Channels.Http
Imports System.Runtime.Remoting.Contexts
Imports System.Runtime.Remoting.Messaging
Imports [Shared]

Public Class Client
    Public Shared Sub Main()
        ' Register Channel
        Dim channel As HttpChannel = New HttpChannel()
        ChannelServices.RegisterChannel(channel, False)

        ' Register MyRemoteObject
        RemotingConfiguration.RegisterWellKnownClientType( _
                GetType(MyRemoteType), _
                "https://localhost:8080/MyRemoteObject")

        ' Add a CallContextString object to the call context
        CallContext.SetData("ServerThreadData", New CallContextString("This is the thread data inserted on the client thread."))

        Console.WriteLine("CallContextString prior to the call: " & CallContext.GetData("ServerThreadData").ToString())
        Dim service As MyRemoteType = New MyRemoteType()
        Console.WriteLine("Server time is: " & service.GetServerTime().ToLongTimeString())
        Console.WriteLine("CallContextString after the call: " & CallContext.GetData("ServerThreadData").ToString())
    End Sub
End Class

[C#]

using System;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels;
using System.Runtime.Remoting.Channels.Http;
using System.Runtime.Remoting.Contexts;
using System.Runtime.Remoting.Messaging;
using Shared;

namespace Client
{
    public class Client
    {
        public static void Main(string[] args)
        {
            // Register Channel
            HttpChannel channel = new HttpChannel();
            ChannelServices.RegisterChannel(channel, false);

            // Register MyRemoteObject
            RemotingConfiguration.RegisterWellKnownClientType(
                typeof(MyRemoteType),
                "https://localhost:8080/MyRemoteObject");

            // Add a CallContextString object to the call context
            CallContext.SetData("ServerThreadData", new CallContextString("This is the thread data inserted on the client thread."));

            Console.WriteLine("CallContextString prior to the call: " + CallContext.GetData("ServerThreadData").ToString());
            MyRemoteType service = new MyRemoteType();
            Console.WriteLine("Server time is: " + service.GetServerTime().ToLongTimeString());
            Console.WriteLine("CallContextString after the call: " + CallContext.GetData("ServerThreadData").ToString());
        }
    }
}

Server

[Visual Basic]

Imports System
Imports System.Runtime.Remoting
Imports System.Runtime.Remoting.Channels
Imports System.Runtime.Remoting.Channels.Http
Imports [Shared]

Public Class Server

    Public Shared Sub Main()
        ' Register channel
        Dim channel As HttpChannel = New HttpChannel(8080)
        ChannelServices.RegisterChannel(channel, False)

        ' Register MyRemoteObject
        RemotingConfiguration.RegisterWellKnownServiceType( _
            GetType(MyRemoteType), _
            "MyRemoteObject", _
            WellKnownObjectMode.SingleCall)

        Console.WriteLine("Press enter to stop this process.")
        Console.ReadLine()
    End Sub

End Class

[C#]

using System;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels;
using System.Runtime.Remoting.Channels.Http;
using Shared;

namespace Server
{
    class Server
    {
        static void Main(string[] args)
        {
            // Register channel
            HttpChannel channel = new HttpChannel(8080);
            ChannelServices.RegisterChannel(channel, false);

            // Register MyRemoteObject
            RemotingConfiguration.RegisterWellKnownServiceType(
                typeof(MyRemoteType),
                "MyRemoteObject",
                WellKnownObjectMode.SingleCall);

            Console.WriteLine("Press enter to stop this process.");
            Console.ReadLine();
        }
    }
}

Siehe auch

Weitere Ressourcen

Remotingbeispiele

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