IAuthenticationModule::Authenticate Method (String^, WebRequest^, ICredentials^)

 

Returns an instance of the Authorization class in respose to an authentication challenge from a server.

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

Authorization^ Authenticate(
	String^ challenge,
	WebRequest^ request,
	ICredentials^ credentials
)

Parameters

challenge
Type: System::String^

The authentication challenge sent by the server.

request
Type: System.Net::WebRequest^

The WebRequest instance associated with the challenge.

credentials
Type: System.Net::ICredentials^

The credentials associated with the challenge.

Return Value

Type: System.Net::Authorization^

An Authorization instance containing the authorization message for the request, or null if the challenge cannot be handled.

The Authenticate method conducts the authentication process with the server and returns an Authorization instance to the AuthenticationManager.

Notes to Implementers:

The AuthenticationManager calls the Authenticate method on registered authentication modules to determine which module handles the challenge. If the authentication module cannot handle the challenge, the Authenticate method must return null. If the authentication module encounters an error while conducting the authentication process, Authenticate must throw an exception.

The following example shows how to use the Authenticate method. For a complete example refer to the AuthenticationManager class.

// Authenticate is the core method for this custom authentication.
// When an internet resource requests authentication, the WebRequest::GetResponse
// method calls the AuthenticationManager::Authenticate method. This method, in
// turn, calls the Authenticate method on each of the registered authentication
// modules, in the order they were registered. When the authentication is
// complete an Authorization object is returned to the WebRequest, as
// shown by this routine's retun type.
virtual Authorization^ Authenticate( String^ challenge, WebRequest^ request, ICredentials^ credentials )
{
   Encoding^ ASCII = Encoding::ASCII;

   // Get the username and password from the credentials
   NetworkCredential^ MyCreds = credentials->GetCredential( request->RequestUri, "Basic" );
   if ( PreAuthenticate( request, credentials ) == nullptr )
         Console::WriteLine( "\n Pre-authentication is not allowed." );
   else
         Console::WriteLine( "\n Pre-authentication is allowed." );


   // Verify that the challenge satisfies the authorization requirements.
   bool challengeOk = checkChallenge( challenge, MyCreds->Domain );
   if (  !challengeOk )
         return nullptr;


   // Create the encrypted string according to the Basic authentication format as
   // follows:
   // a)Concatenate username and password separated by colon;
   // b)Apply ASCII encoding to obtain a stream of bytes;
   // c)Apply Base64 Encoding to this array of bytes to obtain the encoded
   // authorization.
   String^ BasicEncrypt = String::Concat( MyCreds->UserName, ":", MyCreds->Password );
   String^ BasicToken = String::Concat( "Basic ", Convert::ToBase64String( ASCII->GetBytes( BasicEncrypt ) ) );

   // Create an Authorization object using the above encoded authorization.
   Authorization^ resourceAuthorization = gcnew Authorization( BasicToken );

   // Get the Message property which contains the authorization string that the
   // client returns to the server when accessing protected resources
   Console::WriteLine( "\n Authorization Message: {0}", resourceAuthorization->Message );

   // Get the Complete property which is set to true when the authentication process
   // between the client and the server is finished.
   Console::WriteLine( "\n Authorization Complete: {0}", resourceAuthorization->Complete );

   Console::WriteLine( "\n Authorization ConnectionGroupId: {0}", resourceAuthorization->ConnectionGroupId );
   return resourceAuthorization;
}

.NET Framework
Available since 1.1
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