远程处理示例:信道接收器提供程序

本主题介绍一项传统技术,保留该技术是为了向后兼容现有的应用程序,不建议对新的开发使用该技术。现在应该使用  Windows Communication Foundation (WCF) 来开发分布式应用程序。

下面的代码示例会生成一个 ChannelSinkPropertySetterProvider,这是一个信道接收器提供程序,它可以读取客户端应用程序配置文件中的值,并能审核接收器堆栈以查找包含它在该文件中找到的属性的信道接收器。如果要使用配置文件生成接收器链,而不是采用先以编程方式创建该链,再向构造函数传递 IDictionary 对象的方式,则可以使用信道接收器提供程序。

此提供程序不会向信道接收器链中插入任何接收器。它只是通过审核接收器链来查找属性集,您可以方便地对它进行自定义,以使之仅使用特定接收器支持的那些属性。

2ckwbt8a.Caution(zh-cn,VS.100).gif警告:
.NET 远程处理在默认情况下不执行身份验证或加密。因此,在与客户端或服务器进行远程交互之前,建议您先执行所有必要的步骤来验证它们的身份。由于 .NET 远程处理应用程序需要 FullTrust 权限才能执行,因此未经授权的客户端一旦获得服务器的访问权限,它就可以像完全受信任的客户端那样执行代码。应始终验证终结点的身份并对通信流加密,通过在 Internet 信息服务 (IIS) 中承载远程类型,或者通过生成自定义信道接收器对,可以完成这项工作。

2ckwbt8a.note(zh-cn,VS.100).gif注意:
此示例使用硬编码的密码。对密码进行硬编码始终不是一个好的做法,此处这样做只是为了便于说明。获得用户密码的最佳方式是提示用户。

编译和运行此示例

  1. 在命令提示符处,键入下列命令:

    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. 打开指向同一目录的两个命令提示符。在一个命令提示符下,键入 server。当其运行时,在另一个命令提示符下键入 client

    此信道接收提供程序支持使用 writeToConsole 特性来指示是否要对它在客户端控制台中的活动进行控制台转储。在本示例中,该特性设置为 true

    此应用程序可以在一台计算机上运行,也可以在网络上运行。若要在网络上运行此应用程序,请将客户端配置中的**“localhost”**替换为远程计算机的名称。

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;
        } 
    } 

客户端

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());   
   }
}

服务器

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>

另请参见

概念

信道
接收器和接收器链

其他资源

远程处理示例