Exemple de communication à distance : fournisseur de récepteur de canal

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Cette rubrique est spécifique à la technologie héritée assurant la compatibilité descendante avec des applications existantes et n'est pas recommandée en cas de nouveau développement. Les applications distribuées doivent maintenant être développées à l'aide de Windows Communication Foundation (WCF).

L'exemple de code suivant génère un ChannelSinkPropertySetterProvider, qui est un fournisseur de récepteur de canal qui peut lire les valeurs du fichier de configuration de l'application cliente et accompagner la pile du récepteur à la recherche des récepteurs de canal qui contiennent les propriétés qu'il a trouvées dans ce fichier. Cela peut se révéler utile afin de générer une chaîne de récepteurs à l'aide du fichier de configuration plutôt que de créer la chaîne par programme et passer des objets IDictionary aux constructeurs.

Ce fournisseur n'insère pas de récepteur dans la chaîne du récepteur de canal. Il accompagne simplement la chaîne du récepteur à la recherche d'un jeu de propriétés et peut être personnalisé facilement de façon à n'accepter que ces propriétés, prises en charge par un récepteur spécifique.

2ckwbt8a.Caution(fr-fr,VS.100).gifAttention :
Par défaut, .NET Remoting ne procède ni à l'authentification ni au chiffrement. Par conséquent, il est recommandé que vous preniez toutes les mesures nécessaires à l'identification des clients et des serveurs avant d'interagir à distance avec eux. Comme les applications .NET Remoting requièrent des autorisations FullTrust pour s'exécuter, un client non autorisé pourrait exécuter du code comme s'il était d'un niveau de confiance suffisant s'il se voyait accorder l'accès à votre serveur. Veillez à toujours authentifier vos points de terminaison et à chiffrer les flux de données de communication, soit en hébergeant vos types distants dans les Services Internet (IIS), soit en générant une paire de récepteurs de canal dédiée à cette usage.

2ckwbt8a.note(fr-fr,VS.100).gifRemarque :
Cet exemple utilise des mots de passe codés en dur. Il est déconseillé de coder des mots de passe en dur. Cela a été fait ici uniquement à titre d'illustration. La meilleure façon d'obtenir un mot de passe est de le demander à l'utilisateur.

Pour compiler et exécuter cet exemple

  1. À l'invite de commandes, tapez les commandes suivantes :

    vbc /t:library /r:System.Runtime.Remoting.dll /out:PropSink.dll ChannelSinkPropertySetterProvider.vb
vbc /t:library /r:System.Runtime.Remoting.dll serviceclass.vb
vbc /r:System.Runtime.Remoting.dll /r:ServiceClass.dll /r:PropsSink.dll client.vb
vbc /r:System.Runtime.Remoting.dll /r:ServiceClass.dll server.vb

    csc /t:library /r:System.Runtime.Remoting.dll /out:PropSink.dll ChannelSinkPropertySetterProvider.cs
csc /t:library /r:System.Runtime.Remoting.dll serviceclass.cs
csc /r:System.Runtime.Remoting.dll /r:ServiceClass.dll /r:PropSink.dll client.cs
csc /r:System.Runtime.Remoting.dll /r:ServiceClass.dll server.cs

  2. Ouvrez deux invites de commandes qui pointent vers le même répertoire. Dans l'une, tapez server. Une fois le serveur démarré, tapez client au niveau de l'autre invite de commandes.

    Ce fournisseur de récepteur de canal prend en charge l'attribut writeToConsole pour indiquer si vous souhaitez une sortie sur la console du client des activités du fournisseur. Dans cet exemple, l'attribut a la valeur true.

    Cette application peut s'exécuter sur un seul ordinateur ou sur un réseau. Pour exécuter cette application sur un réseau, remplacez « localhost » dans la configuration client par le nom de l'ordinateur distant.

ChannelSinkPropertySetterProvider

Imports System
Imports System.Collections
Imports System.IO
Imports System.Runtime.Remoting
Imports System.Runtime.Remoting.Channels

'This class implements a client-side channel sink provider that
'walks the channel sink chain, looking for channel sink
'properties that match those specified in the configuration file. If it 
'finds them, the provider sets them to the values specified in the 
'configuration file. This is a simple helper provider that returns no 
'channel itself. Instead, it merely returns the next channel sink it can find, or null.
Public Class ChannelSinkPropertySetterProvider
    Implements IClientChannelSinkProvider

    Private _next As IClientChannelSinkProvider = Nothing
    Private _channelSinkProperties As IDictionary = Nothing
    Private _providerData As ICollection = Nothing

    ' Set the writeToConsole attribute on this provider element in the 
    ' configuration file to "true"; otherwise, information is not written to the console.
    Private _consoleDump As Boolean = False

    'Default constructor.
    Public Sub New()
        Console.WriteLine("Default constructor called.")
    End Sub

    'Constructor with properties. If writeToConsole attribute is "true", 
    'this constructor will dump all custom configuration properties set 
    'in the configuration file. 
    Public Sub New(ByVal properties As IDictionary, ByVal providerData As ICollection)
        _channelSinkProperties = properties

        ' Sets the private console dump property for this provider.
        If (properties.Contains("writeToConsole")) Then
            _consoleDump = Boolean.Parse(properties.Item("writeToConsole").ToString)
        End If

        _providerData = providerData

        If (_consoleDump = True) Then
            Console.WriteLine("ChannelSinkPropertySetterProvider custom constructor called.")

            Dim sinkData As SinkProviderData
            For Each sinkData In providerData

                Console.WriteLine("SinkProvider element: " & sinkData.Name)

                Dim prop As DictionaryEntry
                For Each prop In sinkData.Properties
                    Console.WriteLine("Prop name: " & prop.Key.ToString() & " value: " & prop.Value.ToString())
                Next

                Dim child As Object
                For Each child In sinkData.Children
                    Console.WriteLine("Child: " & child.GetType().Name)
                Next

            Next

            Dim entry As DictionaryEntry
            For Each entry In properties

                Console.WriteLine("channel sink properties: " & entry.Key.ToString() & ", " & entry.Value.ToString())
            Next

            Console.WriteLine()
        End If

    End Sub

    'Called by the channel. Normally, this method takes any other sinks 
    'created by other providers in the chain, links them together, and 
    'then returns its own sink to the channel. In this case, this
    'provider merely sets matching properties on each channel sink in the 
    'chain, and then returns the **next** channel sink to the channel or 
    'returns null, indicating to the channel that it is the end of the 
    'custom channel sink chain.
    Public Function CreateSink(ByVal channel As System.Runtime.Remoting.Channels.IChannelSender, ByVal url As String, ByVal remoteChannelData As Object) As System.Runtime.Remoting.Channels.IClientChannelSink Implements System.Runtime.Remoting.Channels.IClientChannelSinkProvider.CreateSink
        If (_consoleDump) Then
            Console.WriteLine("CreateSink is called.")
            Console.WriteLine("By " & channel.ChannelName)
        End If

        Dim nextSink As IClientChannelSink = Nothing

        If (_next IsNot Nothing) Then

            nextSink = _next.CreateSink(channel, url, remoteChannelData)

            If (nextSink Is Nothing) Then
                If (_consoleDump) Then
                    Console.WriteLine("Next sink is null!")
                    Return Nothing
                End If
            End If

            WalkSinkChain(nextSink)

        End If
        Return nextSink
    End Function

    ' This call walks the sink chain, setting properties as it goes.
    ' The channelSinkProperties are the SinkProviderData dictionaries
    ' that contain the name of the subnode in the configuration file, and 
    ' a dictionary entry of attribute/value entries on that element.
    Private Sub WalkSinkChain(ByVal thisSink As IClientChannelSink)
        If (thisSink Is Nothing) Then
            Return
        End If

        If (_consoleDump) Then
            Console.WriteLine("Walking the sink chain to find sink properties... ")
        End If

        While (thisSink IsNot Nothing)
            If (_consoleDump) Then
                Console.WriteLine(New String("_", 80))

                Console.WriteLine("Next sink is : " & CType(thisSink, Object).GetType().Name)
                    DumpSinkProperties(thisSink)

            End If
            SetSinkProperties(thisSink)
            thisSink = thisSink.NextChannelSink
        End While
        Return
    End Sub

    Private Sub DumpSinkProperties(ByVal sink As IClientChannelSink)
        If (sink.Properties Is Nothing) Then
            Console.WriteLine("There are no properties available on the " & CType(sink, Object).GetType().Name + " channelsink.")
            Return
        End If

        Dim entry As DictionaryEntry
        For Each entry In sink.Properties
            Console.Write("ChannelSink property: " & entry.Key.ToString() & " value: ")
            If (entry.Value Is Nothing) Then
                Console.WriteLine("No value.")
            Else
                Console.WriteLine(entry.Value.ToString())
            End If
        Next
    End Sub

    ' This method sets properties on the sink.
    ' The algorithm is that in the absence of instance attribute/value 
    ' entries, the provider element template attribute/value entries will 
    ' be set. This is a simple implementation that does not care about the 
    ' element name underneath the provider element.
    Private Sub SetSinkProperties(ByVal sink As IClientChannelSink)
        If (sink.Properties Is Nothing) Then
            Console.WriteLine("There are no properties available on the " & CType(sink.Properties, Object).GetType().Name & " channelsink.")
            Return
        End If

        Dim entry As DictionaryEntry
        For Each entry In sink.Properties
            If (_channelSinkProperties.Contains(entry.Key)) Then
                If (_consoleDump) Then
                    Console.WriteLine("Setting sink property template on " & CType(sink, Object).GetType().Name & "." & entry.Key.ToString())
                End If
                sink.Properties.Item(entry.Key) = _channelSinkProperties.Item(entry.Key)
            End If
        Next

        Dim provider As SinkProviderData
        For Each provider In _providerData
            Dim configEntry As DictionaryEntry
            For Each configEntry In provider.Properties
                If (sink.Properties.Contains(configEntry.Key)) Then
                    If (_consoleDump) Then
                        Console.WriteLine("Setting Instance override on " & CType(sink, Object).GetType().Name & "." & configEntry.Key)
                    End If
                End If
                sink.Properties.Item(configEntry.Key) = configEntry.Value
            Next
        Next

        If (_consoleDump) Then
            DumpSinkProperties(sink)
        End If
    End Sub
    Public Property [Next]() As System.Runtime.Remoting.Channels.IClientChannelSinkProvider Implements System.Runtime.Remoting.Channels.IClientChannelSinkProvider.Next
        Get
            Return _next
        End Get
        Set(ByVal value As System.Runtime.Remoting.Channels.IClientChannelSinkProvider)
            _next = value
        End Set
    End Property

    ' This can be called in the constructor in case this provider is 
    ' intended to build its own channel sink provider chain. Without 
    ' providing such a chain, this provider must be specified in a 
    ' configuration file with other providers.
    Private Function CreateDefaultClientProviderChain() As IClientChannelSinkProvider
        Dim chain As IClientChannelSinkProvider = New SoapClientFormatterSinkProvider()
        Dim sink As IClientChannelSinkProvider = chain

        sink.Next = New BinaryClientFormatterSinkProvider()
        sink = sink.Next

        Return chain
    End Function
End Class

using System;
using System.Collections;
using System.IO;
using System.Reflection;
using System.Runtime.Remoting;
using System.Runtime.Remoting.Channels;
using System.Runtime.Remoting.Channels.Http;
using System.Runtime.Remoting.Messaging;
using System.Runtime.Remoting.MetadataServices;

    // This class implements a client-side channel sink provider that
    // walks the channel sink chain, looking for channel sink
    // properties that match those specified in the configuration file. If it 
    // finds them, the provider sets them to the values specified in the 
    // configuration file. This is a simple helper provider that returns no 
    // channel itself. Instead, it merely returns the next channel sink it can find, or null.

    public class ChannelSinkPropertySetterProvider : IClientChannelSinkProvider
    {
        private IClientChannelSinkProvider _next = null;
        private IDictionary _channelSinkProperties = null;
        private ICollection _providerData = null;

        // Set the writeToConsole attribute on this provider element in the 
        // configuration file to "true"; otherwise, information is not written to the console.
        private bool _consoleDump = true;

        // Default constructor.
        public ChannelSinkPropertySetterProvider()
        {
            Console.WriteLine("Default constructor called.");
        } 

        // Constructor with properties. If writeToConsole attribute is "true", 
        // this constructor will dump all custom configuration properties set 
        // in the configuration file. 
        public ChannelSinkPropertySetterProvider(IDictionary properties, ICollection providerData)
        {
            _channelSinkProperties = properties;

            // Sets the private console dump property for this provider.
            if (properties["writeToConsole"] != null)
                _consoleDump = Boolean.Parse(properties["writeToConsole"].ToString());

            _providerData = providerData;

            if (_consoleDump)
            {
                Console.WriteLine("ChannelSinkPropertySetterProvider custom constructor called.");

                foreach (SinkProviderData sinkData in providerData)
                {
                    Console.WriteLine("SinkProvider element: " + sinkData.Name);
                    foreach (DictionaryEntry prop in sinkData.Properties)
                    {
                        Console.WriteLine("Prop name: " + prop.Key.ToString() + " value: " + prop.Value.ToString());
                    }

                    foreach (object child in sinkData.Children)
                    {
                        Console.WriteLine("Child: " + child.GetType().Name);
                    }
                }

                foreach (DictionaryEntry entry in properties)
                {
                    Console.WriteLine("channel sink properties: " + entry.Key.ToString() + ", " + entry.Value.ToString());
                }

                Console.WriteLine();
            }
        } 

        // Called by the channel. Normally, this method takes any other sinks 
        // created by other providers in the chain, links them together, and 
        // then returns its own sink to the channel. In this case, this
        // provider merely sets matching properties on each channel sink in the 
        // chain, and then returns the **next** channel sink to the channel or 
        // returns null, indicating to the channel that it is the end of the 
        // custom channel sink chain.
        public IClientChannelSink CreateSink(IChannelSender channel, string url, object remoteChannelData)
        {
            if (_consoleDump)
            {
                Console.WriteLine("CreateSink is called.");
                Console.WriteLine("By " + channel.GetType().Name);
            }

            IClientChannelSink nextSink = null;

            if (_next != null)
            {

                nextSink = _next.CreateSink(channel, url, remoteChannelData);

                if (nextSink == null)
                {
                    if (_consoleDump)
                        Console.WriteLine("Next sink is null!");
                    return null;
                }

                WalkSinkChain(nextSink);

            }

            return nextSink;

        }

        // This call walks the sink chain, setting properties as it goes.
        // The channelSinkProperties are the SinkProviderData dictionaries
        // that contain the name of the subnode in the configuration file, and 
        // a dictionary entry of attribute/value entries on that element.

        private void WalkSinkChain(IClientChannelSink thisSink)
        {

            if (thisSink == null)
                return;

            if (_consoleDump)
                Console.WriteLine("\r\n\tWalking the sink chain to find sink properties... \r\n");

            while (thisSink != null)
            {
                if (_consoleDump)
                {
                    Console.WriteLine(new String('_', 80));
                    Console.WriteLine("Next sink is : " + thisSink.GetType().Name);
                    DumpSinkProperties(thisSink);
                }
                SetSinkProperties(thisSink);
                thisSink = thisSink.NextChannelSink;
            }

            return;
        }

        private void DumpSinkProperties(IClientChannelSink sink)
        {

            if (sink.Properties == null)
            {
                Console.WriteLine("There are no properties available on the " + sink.GetType().Name + " channelsink.");
                return;
            }

            foreach (DictionaryEntry entry in sink.Properties)
            {
                Console.Write("ChannelSink property: " + entry.Key.ToString() + " value: ");
                if (entry.Value == null)
                    Console.WriteLine("No value.");
                else
                    Console.WriteLine(entry.Value.ToString());
            }

        }

        // This method sets properties on the sink.
        // The algorithm is that in the absence of instance attribute/value 
        // entries, the provider element template attribute/value entries will 
        // be set. This is a simple implementation that does not care about the 
        // element name underneath the provider element.

        private void SetSinkProperties(IClientChannelSink sink)
        {

            if (sink.Properties == null)
            {
                Console.WriteLine("There are no properties available on the " + sink.GetType().Name + " channelsink.");
                return;
            }

            foreach (DictionaryEntry entry in sink.Properties)
            {
                if (_channelSinkProperties.Contains(entry.Key))
                {

                    if (_consoleDump)
                        Console.WriteLine("Setting sink property template on " + sink.GetType().Name + "." + entry.Key.ToString());
                    sink.Properties[entry.Key] = _channelSinkProperties[entry.Key];
                }
            }

            foreach (SinkProviderData provider in _providerData)
            {
                foreach (DictionaryEntry configEntry in provider.Properties)
                {
                    if (sink.Properties.Contains(configEntry.Key))
                        if (_consoleDump)
                            Console.WriteLine("Setting Instance override on " + sink.GetType().Name + "." + configEntry.Key);
                    sink.Properties[configEntry.Key] = configEntry.Value;
                }
            }

            if (_consoleDump)
                DumpSinkProperties(sink);
        }

        public IClientChannelSinkProvider Next
        {
            get
            {
                return _next;
            }

            set
            {
                _next = value;
            }
        }

        // This can be called in the constructor in case this provider is 
        // intended to build its own channel sink provider chain. Without 
        // providing such a chain, this provider must be specified in a 
        // configuration file with other providers.
        private IClientChannelSinkProvider CreateDefaultClientProviderChain()
        {

            IClientChannelSinkProvider chain = new SoapClientFormatterSinkProvider();
            IClientChannelSinkProvider sink = chain;

            sink.Next = new BinaryClientFormatterSinkProvider();
            sink = sink.Next;

            return chain;
        } 
    }

Client

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

Public Class Client

    Shared Sub Main()
        RemotingConfiguration.Configure("Client.exe.config", False)
        Dim service As ServiceClass = New ServiceClass()
        Console.WriteLine(service.GetServerTime())
    End Sub

End Class

using System;
using System.Runtime.Remoting;

public class Client
{ 
   public static void Main(string[] Args)
   {
      RemotingConfiguration.Configure("Client.exe.config", false);
      ServiceClass service = new ServiceClass();
      Console.WriteLine(service.GetServerTime());   
   }
}

Server

Imports System
Imports System.Runtime.Remoting

Class Server

    Shared Sub Main()
        RemotingConfiguration.Configure("server.exe.config", False)
        Console.WriteLine("Press enter to stop this process.")
        Console.ReadLine()
    End Sub

End Class

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

public class ServerProcess
{
   public static void Main(string[] Args)
   {
      RemotingConfiguration.Configure("server.exe.config");
      Console.WriteLine("Press enter to stop this process.");
      Console.ReadLine(); 
   }
}

ServiceClass

Imports System
Imports System.Runtime.Remoting

Public Class ServiceClass
    Inherits MarshalByRefObject

    Private starttime As DateTime

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

    Protected Overrides Sub Finalize()
        Console.WriteLine("This object is 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.")
        Return DateTime.Now
    End Function
End Class

using System;
using System.Runtime.Remoting;

public class ServiceClass : MarshalByRefObject
{
    private DateTime starttime;

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

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

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

Client.exe.config

<configuration>
  <system.runtime.remoting>
    <application>
      <client>
         <wellknown 
            type="ServiceClass, ServiceClass"
            url="https://localhost:8080/RemoteObject"
         />
      </client>
      <channels>
         <channel ref="http">
         <clientProviders>
            <formatter ref="soap"/>
            <provider ref="propsetter" username="bob" writeToConsole="true">
               <myElement allowAutoRedirect="true"/>
               <endpoint preauthenticate="true"/>
               <endpoint url="example.com:9000" password="xyz" />
               <endpoint url="example.com:9001" password="123" />
               <endpoint timeout="10000"/>
               <endpoint url="example.com:*" username="bob2" password="qwerty" domain="hello" />
            </provider>
         </clientProviders>
         </channel>
      </channels>
   </application>
   <channelSinkProviders>
      <clientProviders>
         <provider 
            id="propsetter" 
            type="ChannelSinkPropertySetterProvider, PropSink" 
         />
      </clientProviders>
   </channelSinkProviders>
   <debug loadTypes="true" />
  </system.runtime.remoting>
</configuration>

Server.exe.config

<configuration>
  <system.runtime.remoting>
    <application>
      <service>
        <wellknown mode="SingleCall" 
           type="ServiceClass, ServiceClass" 
           objectUri="RemoteObject" 
        />
      </service>
      <channels>
        <channel port="8080" ref="http" />
      </channels>
    </application>
  </system.runtime.remoting>
</configuration>

Voir aussi

Concepts

Canaux
Récepteurs et chaînes de récepteurs

Autres ressources

Exemples de communication à distance