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IAuthenticationModule.Authenticate Method

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

[Visual Basic]
Function Authenticate( _
   ByVal challenge As String, _
   ByVal request As WebRequest, _
   ByVal credentials As ICredentials _
) As Authorization
[C#]
Authorization Authenticate(
   string challenge,
 WebRequest request,
 ICredentials credentials
);
[C++]
Authorization* Authenticate(
   String* challenge,
 WebRequest* request,
 ICredentials* credentials
);
[JScript]
function Authenticate(
   challenge : String,
 request : WebRequest,
 credentials : ICredentials
) : Authorization;

Parameters

challenge
The authentication challenge sent by the server.
request
The WebRequest instance associated with the challenge.
credentials
The credentials associated with the challenge.

Return Value

An Authorization instance containing the authorization message for the request, or a null reference (Nothing in Visual Basic) if the challenge cannot be handled.

Remarks

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 a null reference (Nothing in Visual Basic). If the authentication module encounters an error while conducting the authentication process, Authenticate must throw an exception.

Example

[Visual Basic, C#, C++] The following example shows how to use the Authenticate method. For a complete example refer to the AuthenticationManager class.

[Visual Basic] 
' 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 in which they were registered. When the authentication is 
' complete an Authorization object is returned to the WebRequest.
Public Function Authenticate(ByVal challenge As String, ByVal request As WebRequest, ByVal credentials As ICredentials) As Authorization _
    Implements IAuthenticationModule.Authenticate


  Dim ASCII As Encoding = Encoding.ASCII

  ' Get the username and password from the credentials
  Dim MyCreds As NetworkCredential = credentials.GetCredential(request.RequestUri, "Basic")

  If PreAuthenticate(request, credentials) Is Nothing Then
    Console.WriteLine(ControlChars.Lf + " Pre-authentication is not allowed.")
  Else
    Console.WriteLine(ControlChars.Lf + " Pre-authentication is allowed.")
  End If
  ' Verify that the challenge satisfies the authorization requirements.
  Dim challengeOk As Boolean = checkChallenge(challenge, MyCreds.Domain)

  If Not challengeOk Then
    Return Nothing
  End If

  ' Create the encrypted string according to the Basic authentication format as
  ' follows:
  ' a)Concatenate the 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.
  Dim BasicEncrypt As String = MyCreds.UserName + ":" + MyCreds.Password

  Dim BasicToken As String = "Basic " + Convert.ToBase64String(ASCII.GetBytes(BasicEncrypt))

  ' Create an Authorization object using the encoded authorization above.
  Dim resourceAuthorization As New Authorization(BasicToken)

  ' Get the Message property, which contains the authorization string that the 
  ' client returns to the server when accessing protected resources.
  Console.WriteLine(ControlChars.Lf + " 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(ControlChars.Lf + " Authorization Complete:{0}", resourceAuthorization.Complete)

  Console.WriteLine(ControlChars.Lf + " Authorization ConnectionGroupId:{0}", resourceAuthorization.ConnectionGroupId)


  Return resourceAuthorization
End Function 'Authenticate
    End Class 'CustomBasic 

[C#] 
// 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 in which they were registered. When the authentication is 
// complete an Authorization object is returned to the WebRequest.
public 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) == null)
    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 null;

  // Create the encrypted string according to the Basic authentication format as
  // follows:
  // a)Concatenate the 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 = MyCreds.UserName + ":" + MyCreds.Password;

  string BasicToken = "Basic " + Convert.ToBase64String(ASCII.GetBytes(BasicEncrypt));

  // Create an Authorization object using the encoded authorization above.
  Authorization resourceAuthorization = new 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;
}

[C++] 
// 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.
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, S"Basic");

   if (PreAuthenticate(request, credentials) == 0)
      Console::WriteLine(S"\n Pre-authentication is not allowed.");
   else
      Console::WriteLine(S"\n Pre-authentication is allowed.");

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

   if (!challengeOk)
      return 0;

   // 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, S":", MyCreds->Password);

   String* BasicToken = 
      String::Concat(S"Basic ", Convert::ToBase64String(ASCII->GetBytes(BasicEncrypt)));

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

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

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

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family, .NET Compact Framework, Common Language Infrastructure (CLI) Standard

See Also

IAuthenticationModule Interface | IAuthenticationModule Members | System.Net Namespace

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