Remoting Example: Channel Sink Provider
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 following code example builds a ChannelSinkPropertySetterProvider, which is a channel sink provider that can read values in the client application's configuration file and walk the sink stack looking for channel sinks that contain the properties it found in that file. This is useful to build a sink chain using the configuration file rather than creating the chain programmatically and passing IDictionary objects to the constructors.
This provider does not insert any sink into the channel sink chain. It merely walks the sink chain looking for a set of properties and can easily be customized to take only those properties supported by a specific sink.
.gif "2ckwbt8a.Caution(en-us,VS.100).gif") Caution: |
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| .NET Remoting does not perform authentication or encryption by default. Therefore, it is recommended that you take all necessary steps to verify the identity of clients or servers before interacting with them remotely. Because .NET 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. |
.gif "2ckwbt8a.note(en-us,VS.100).gif") Note: |
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| This sample uses hard-coded passwords. It is never a good idea to hard-code passwords and is done here for illustrative purposes only. The best way to get a password from a user is to prompt the user. |
To compile and run this sample
Type the following commands at the command prompt:
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.vbcsc /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.csOpen two command prompts pointing to the same directory. In one, type server. When that is running, type client at the other command prompt.
This channel sink provider supports the writeToConsole attribute to indicate whether you want a console dump of the provider's activities in the client console. For this example, the attribute is set to true.
This application runs on a single computer or across a network. To run this application over a network, replace "localhost" in the client configuration with the name of the remote computer.
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>
See Also
Concepts
Channels
Sinks and Sink Chains