OperationBehaviorAttribute.Impersonation Property

Definition

Namespace:

System.ServiceModel

Assembly:

System.ServiceModel.dll

Gets or sets a value that indicates the level of caller impersonation that the operation supports.

public:
 property System::ServiceModel::ImpersonationOption Impersonation { System::ServiceModel::ImpersonationOption get(); void set(System::ServiceModel::ImpersonationOption value); };

public System.ServiceModel.ImpersonationOption Impersonation { get; set; }

member this.Impersonation : System.ServiceModel.ImpersonationOption with get, set

Public Property Impersonation As ImpersonationOption

Property Value

ImpersonationOption

One of the ImpersonationOption values. The default is NotAllowed.

Examples

The following service code example requires impersonation by setting the Impersonation property to Required.

using System;
using System.Collections.Generic;
using System.ServiceModel;
using System.Threading;

namespace Microsoft.WCF.Documentation
{
  [ServiceContract(
    Name="SampleHello",
    Namespace="http://microsoft.wcf.documentation"
  )]
  public interface IHello
  {
    [OperationContract]
    string Hello(string greeting);
  }

  public class HelloService : IHello
  {

    public HelloService()
    {
      Console.WriteLine("Service object created: " + this.GetHashCode().ToString());
    }

    ~HelloService()
    {
      Console.WriteLine("Service object destroyed: " + this.GetHashCode().ToString());
    }

    [OperationBehavior(Impersonation=ImpersonationOption.Required)]
    public string Hello(string greeting)
    {
      Console.WriteLine("Called by: " + Thread.CurrentPrincipal.Identity.Name);
      Console.WriteLine("IsAuthenticated: " + Thread.CurrentPrincipal.Identity.IsAuthenticated.ToString());
      Console.WriteLine("AuthenticationType: " + Thread.CurrentPrincipal.Identity.AuthenticationType.ToString());

      Console.WriteLine("Caller sent: " + greeting);
      Console.WriteLine("Sending back: Hi, " + Thread.CurrentPrincipal.Identity.Name);
      return "Hi, " + Thread.CurrentPrincipal.Identity.Name;
    }
  }
}

Imports System.ServiceModel
Imports System.Threading

Namespace Microsoft.WCF.Documentation
  <ServiceContract(Name:="SampleHello", Namespace:="http://microsoft.wcf.documentation")> _
  Public Interface IHello
    <OperationContract> _
    Function Hello(ByVal greeting As String) As String
  End Interface

  Public Class HelloService
      Implements IHello

    Public Sub New()
      Console.WriteLine("Service object created: " & Me.GetHashCode().ToString())
    End Sub

    Protected Overrides Sub Finalize()
      Console.WriteLine("Service object destroyed: " & Me.GetHashCode().ToString())
    End Sub

    <OperationBehavior(Impersonation:=ImpersonationOption.Required)> _
    Public Function Hello(ByVal greeting As String) As String Implements IHello.Hello
      Console.WriteLine("Called by: " & Thread.CurrentPrincipal.Identity.Name)
      Console.WriteLine("IsAuthenticated: " & Thread.CurrentPrincipal.Identity.IsAuthenticated.ToString())
      Console.WriteLine("AuthenticationType: " & Thread.CurrentPrincipal.Identity.AuthenticationType.ToString())

      Console.WriteLine("Caller sent: " & greeting)
      Console.WriteLine("Sending back: Hi, " & Thread.CurrentPrincipal.Identity.Name)
      Return "Hi, " & Thread.CurrentPrincipal.Identity.Name
    End Function
  End Class
End Namespace

The following code example shows using the ClientCredentials property to set the client application credentials prior to invoking the operation that requires those credentials for impersonation.

using System;
using System.ServiceModel;
using System.ServiceModel.Channels;
using System.Security.Principal;
using System.Threading;

namespace Microsoft.WCF.Documentation
{
  public class Client
  {
    public void Run()
    {
      // Picks up configuration from the config file.
      SampleHelloClient wcfClient = new SampleHelloClient();
      try
      {
        // Set the client credentials to permit impersonation. You can do this programmatically or in the configuration file.
        wcfClient.ClientCredentials.Windows.AllowedImpersonationLevel = TokenImpersonationLevel.Impersonation;

        // Make calls using the proxy.
        Console.ForegroundColor = ConsoleColor.White;
        Console.WriteLine("Enter a greeting to send and press ENTER: ");
        Console.Write(">>> ");
        Console.ForegroundColor = ConsoleColor.Green;
        string greeting = Console.ReadLine();
        Console.ForegroundColor = ConsoleColor.White;
        Console.WriteLine("Called service with: \r\n\t" + greeting);
        Console.WriteLine("Service returned: " + wcfClient.Hello(greeting));
        Console.ForegroundColor = ConsoleColor.Blue;
        Console.Write("Press ");
        Console.ForegroundColor = ConsoleColor.Red;
        Console.Write("ENTER");
        Console.ForegroundColor = ConsoleColor.Blue;
        Console.Write(" to exit...");
        Console.ReadLine();
        wcfClient.Close();
      }
      catch (TimeoutException timeProblem)
      {
        Console.WriteLine("The service operation timed out. " + timeProblem.Message);
        wcfClient.Abort();
        Console.Read();
      }
      catch (CommunicationException commProblem)
      {
        Console.WriteLine("There was a communication problem. " + commProblem.Message);
        wcfClient.Abort();
        Console.Read();
      }
    }
    public static void Main()
    {
      Client client = new Client();
      client.Run();
    }
  }
}

Imports System.ServiceModel
Imports System.ServiceModel.Channels
Imports System.Security.Principal
Imports System.Threading

Namespace Microsoft.WCF.Documentation
  Public Class Client
    Public Sub Run()
      ' Picks up configuration from the config file.
      Dim wcfClient As New SampleHelloClient()
      Try
        ' Set the client credentials to permit impersonation. You can do this programmatically or in the configuration file.
        wcfClient.ClientCredentials.Windows.AllowedImpersonationLevel = TokenImpersonationLevel.Impersonation

        ' Make calls using the proxy.
        Console.ForegroundColor = ConsoleColor.White
        Console.WriteLine("Enter a greeting to send and press ENTER: ")
        Console.Write(">>> ")
        Console.ForegroundColor = ConsoleColor.Green
                Dim greeting = Console.ReadLine()
        Console.ForegroundColor = ConsoleColor.White
        Console.WriteLine("Called service with: " & vbCrLf & vbTab & greeting)
        Console.WriteLine("Service returned: " & wcfClient.Hello(greeting))
        Console.ForegroundColor = ConsoleColor.Blue
        Console.Write("Press ")
        Console.ForegroundColor = ConsoleColor.Red
        Console.Write("ENTER")
        Console.ForegroundColor = ConsoleColor.Blue
        Console.Write(" to exit...")
        Console.ReadLine()
        wcfClient.Close()
      Catch timeProblem As TimeoutException
        Console.WriteLine("The service operation timed out. " & timeProblem.Message)
        wcfClient.Abort()
        Console.Read()
      Catch commProblem As CommunicationException
        Console.WriteLine("There was a communication problem. " & commProblem.Message)
        wcfClient.Abort()
        Console.Read()
      End Try
    End Sub
    Public Shared Sub Main()
      Dim client As New Client()
      client.Run()
    End Sub
  End Class
End Namespace

Remarks

Use the Impersonation property (together with a binding configuration that supports impersonation) to enable specified methods (those marked with the Impersonation property set to Allowed or Required) to execute under the caller's identity. For details, including how impersonation is performed when using Allowed together with the ServiceAuthorizationBehavior.ImpersonateCallerForAllOperations property, see Delegation and Impersonation and How to: Impersonate a Client on a Service.

Note

When programmatically adding a service endpoint that performs impersonation, you must either use one of the AddServiceEndpoint methods or the ContractDescription.GetContract method to properly load the contract into a new System.ServiceModel.Description.ServiceDescription object. Using a configuration file requires no extra step.

There may be specific scenarios when impersonation is not supported. For more information, see Unsupported Scenarios.