Esempio di .NET Remoting Durate

Nell'esempio di codice seguente vengono illustrati molti scenari di lease di durata. Client.exe registra uno sponsor che (dopo la durata del lease iniziale) rinnova il lease per un TimeSpan diverso da quello specificato in ClientActivatedType.InitializeLifetimeService(). Tenere presente che MyClientSponsor estende MarshalByRefObject per renserlo passabile per riferimento al gestore di lease (nel dominio dell'applicazione Server.exe). Questa applicazione è in esecuzione su un solo computer o attraverso una rete. Se si desidera eseguire questa applicazione su una rete, sarà necessario sostituire "localhost" nella configurazione client con il nome del computer remoto.

Attenzione:

.NET Remoting non esegue l'autenticazione o la crittografia per impostazione predefinita. È pertanto consigliato che vengano effettuati tutti i passaggi necessari per verificare l'identità di client o server prima di interagirvi in modalità remota. Poiché le applicazioni di .NET Remoting richiedono autorizzazioni di tipo FullTrust per essere eseguite, se si concede l'accesso al proprio server a un client non autorizzato, questi potrebbe eseguire codice come se fosse completamente attendibile. Autenticare sempre gli endpoint e crittografare i flussi di comunicazione eseguendo l'hosting dei tipi remoti in Internet Information Services (IIS) o compilando una coppia di sink di canale personalizzata per eseguire questo lavoro.

Eseguire Server.exe e quindi Client.exe. L'output dovrebbe essere simile al seguente:

Server.exe:

C:\projects\Lifetime\Server\bin>server

The server is listening. Press Enter to exit....

ClientActivatedType.RemoteMethod called.

Client.exe:

C:\projects\Lifetime\Client\bin>client

Client-activated object: RemoteMethod called. MyDomain\SomeUser

Press Enter to end the client application domain.

I've been asked to renew the lease.

Time since last renewal:00:00:09.9432506

I've been asked to renew the lease.

Time since last renewal:00:00:29.9237760

Per compilare questo esempio

• Digitare i comandi seguenti nel prompt dei comandi:

  [C#]

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

[Visual Basic]

RemoteType

[C#]

using System;
using System.Runtime.Remoting.Lifetime;
using System.Security.Principal;

namespace RemoteType
{
    public class ClientActivatedType : MarshalByRefObject
    {
        public override Object InitializeLifetimeService()
        {
            ILease lease = (ILease)base.InitializeLifetimeService();

            // Normally, the initial lease time would be much longer.
            // It is shortened here for demonstration purposes.
            if (lease.CurrentState == LeaseState.Initial)
            {
                lease.InitialLeaseTime = TimeSpan.FromSeconds(3);
                lease.SponsorshipTimeout = TimeSpan.FromSeconds(10);
                lease.RenewOnCallTime = TimeSpan.FromSeconds(2);
            }
            return lease;
        }

        public string RemoteMethod()
        {
            // Announces to the server that the method has been called.
            Console.WriteLine("ClientActivatedType.RemoteMethod called.");

            // Reports the client identity name.
            return "RemoteMethod called. " + WindowsIdentity.GetCurrent().Name;
        }
    }
}

[Visual Basic]

Imports System
Imports System.Runtime.Remoting.Lifetime
Imports System.Security.Principal

Namespace RemoteType
Public Class ClientActivatedType
    Inherits MarshalByRefObject

    Public Overrides Function InitializeLifetimeService() As Object
        Dim lease As ILease = MyBase.InitializeLifetimeService()

        ' Normally, the initial lease time would be much longer.
        ' It is shortened here for demonstration purposes.
        If (lease.CurrentState = LeaseState.Initial) Then
            lease.InitialLeaseTime = TimeSpan.FromSeconds(3)
            lease.SponsorshipTimeout = TimeSpan.FromSeconds(10)
            lease.RenewOnCallTime = TimeSpan.FromSeconds(2)
        End If
        Return lease
    End Function

    Public Function RemoteMethod() As String
        Console.WriteLine("ClientActivatedType.RemoteMethod called.")

        ' Reports the client identity name.
        Return "RemoteMethod called. " & WindowsIdentity.GetCurrent().Name
    End Function

End Class
End Namespace

Server

using System;
using System.Runtime.Remoting;

namespace Server
{
    class Program
    {
        static void Main(string[] args)
        {
            RemotingConfiguration.Configure("Server.exe.config", false);
            Console.WriteLine("The server is listening. Press Enter to exit....");
            Console.ReadLine();
        }
    }
}

Imports System
Imports System.Runtime.Remoting

Class Program
    Shared Sub Main()
        RemotingConfiguration.Configure("Server.exe.config", False)
        Console.WriteLine("The server is listening. Press Enter to exit....")
        Console.ReadLine()
    End Sub
End Class

Server.exe.config

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <system.runtime.remoting>
    <application>
      <channels>
        <channel ref="tcp" port="1234">
          <serverProviders>
            <formatter ref="binary" typeFilterLevel="Full"/>
          </serverProviders>
          <clientProviders>
            <formatter ref="binary"/>
          </clientProviders>
        </channel>
      </channels>
      <service>
        <activated type="RemoteType.ClientActivatedType, RemoteType" />
      </service>
    </application>
  </system.runtime.remoting>
</configuration>

Client

using System;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Lifetime;
using RemoteType;

class Client
{
    static void Main(string[] args)
    {
        RemotingConfiguration.Configure("Client.exe.config",false);
        ClientActivatedType obj = new ClientActivatedType();

        ILease lease = (ILease)obj.GetLifetimeService();
        MyClientSponsor sponsor = new MyClientSponsor();
        lease.Register(sponsor);

        Console.WriteLine("Client-activated object: " + obj.RemoteMethod());
        Console.WriteLine("Press Enter to end the client application domain.");
        Console.ReadLine();
    }
}

public class MyClientSponsor : MarshalByRefObject, ISponsor
{
    private DateTime lastRenewal;

    public MyClientSponsor()
    {
        Console.WriteLine("MyClientSponsor.ctor called");
        lastRenewal = DateTime.Now;
    }

    public TimeSpan Renewal(ILease lease)
    {
        Console.WriteLine("I've been asked to renew the lease.");
        Console.WriteLine("Time since last renewal:" + (DateTime.Now - lastRenewal).ToString());

        lastRenewal = DateTime.Now;
        return TimeSpan.FromSeconds(20);
    }
}

Imports System
Imports System.Runtime.Remoting
Imports System.Runtime.Remoting.Lifetime
Imports RemoteType

Class Client

    Shared Sub Main()
        RemotingConfiguration.Configure("Client.exe.config", False)
        Dim obj As ClientActivatedType = New ClientActivatedType()

        Dim lease As ILease = CType(obj.GetLifetimeService(), ILease)
        Dim sponsor As MyClientSponsor = New MyClientSponsor()
        lease.Register(sponsor)

        Console.WriteLine("Client-activated object: " + obj.RemoteMethod())
        Console.WriteLine("Press Enter to end the client application domain.")
        Console.ReadLine()
    End Sub

End Class

Public Class MyClientSponsor
    Inherits MarshalByRefObject
    Implements ISponsor

    Dim lastRenewal As DateTime

    Public Sub New()
        lastRenewal = DateTime.Now
    End Sub

    Public Function Renewal(ByVal lease As System.Runtime.Remoting.Lifetime.ILease) As System.TimeSpan Implements System.Runtime.Remoting.Lifetime.ISponsor.Renewal
        Console.WriteLine("I've been asked to renew the lease.")
        Console.WriteLine("Time since last renewal:" + (DateTime.Now - lastRenewal).ToString())

        lastRenewal = DateTime.Now
        Return TimeSpan.FromSeconds(20)
    End Function
End Class

Client.exe.config

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <system.runtime.remoting>
    <application>
      <channels>
        <channel ref="tcp" port="0">
          <clientProviders>
            <formatter ref="binary"/>
          </clientProviders>
          <serverProviders>
            <formatter ref="binary" typeFilterLevel="Full"/>
          </serverProviders>
        </channel>
      </channels>
      <client url="tcp://localhost:1234">
        <activated type="RemoteType.ClientActivatedType, RemoteType" />
      </client>
    </application>
  </system.runtime.remoting>
</configuration>

Vedere anche

Altre risorse

Esempi di .NET Remoting
Attivazione e durate degli oggetti

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