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ICredentialPolicy Interface

Defines the credential policy to be used for resource requests that are made using WebRequest and its derived classes.

Namespace:  System.Net
Assembly:  System (in System.dll)

public interface ICredentialPolicy

The ICredentialPolicy type exposes the following members.

  NameDescription
Public methodShouldSendCredentialReturns a Boolean that indicates whether the client's credentials are sent with a resource request made using an instance of the WebRequest class.
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The credential policy determines whether to send credentials when sending a WebRequest for a network resource, such as the content of a Web page. If credentials are sent, servers that require client authentication can attempt to authenticate the client when the request is received instead of sending a response that indicates that the client's credentials are required. While this saves a round trip to the server, this performance gain must be balanced against the security risk inherent in sending credentials across the network. When the destination server does not require client authentication, it is best not to send credentials.

NoteNote

ICredentialPolicy policies are invoked only if the WebRequest or the WebProxy that is associated with the request has credentials that are not null. Setting this policy has no effect on requests that do not specify credentials.

Use the AuthenticationManager.CredentialPolicy property to set an ICredentialPolicy policy. The IAuthenticationModule that handles authentication for the request will invoke the ShouldSendCredential method before performing the authentication. If the method returns false, authentication is not performed.

An ICredentialPolicy policy affects all instances of WebRequest with non-null credentials in the current application domain. The policy cannot be overridden on individual requests.

The following code example shows an implementation of this interface that permits credentials to be sent only for requests that target specific hosts.

public class SelectedHostsCredentialPolicy: ICredentialPolicy
{
    public SelectedHostsCredentialPolicy()
    {
    }

    public virtual bool ShouldSendCredential(Uri challengeUri, 
        WebRequest request, 
        NetworkCredential credential, 
        IAuthenticationModule authModule)
    {
        Console.WriteLine("Checking custom credential policy.");
        if (request.RequestUri.Host == "www.contoso.com" ||
            challengeUri.IsLoopback == true)
            return true;

        return false;
    }
}

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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