AuthenticationManager 類別

定義

命名空間:

System.Net

組件:

System.Net.Requests.dll

來源:

AuthenticationManager.cs

管理在用戶端驗證 (Authentication) 處理期間所呼叫的驗證模組。

public ref class AuthenticationManager

public class AuthenticationManager

type AuthenticationManager = class

Public Class AuthenticationManager

繼承

Object

AuthenticationManager

範例

// This program shows how to create a custom Basic authentication module,
// how to register it via the AuthenticationManager class and how to authorize
// users to access a Web site.
// Note: In order to run this program you must create a test Web site that performs
// Basic authentication. Also you must add to your server machine a user whose
// credentials are the same you use in this program.
// Attention: Basic authenticastion sends the user's credentials over HTTP.
// Passwords and user names are encoded using Base64 encoding. Although the
// user information is encoded, it is considered insecure due to the fact that it
// could be deciphered relatively easily.
// If you must use basic authentication you are strongly adviced to use strong
// security mechanisms, such as SSL, when transfering sensitive information on
// the wire.
#using <System.dll>

using namespace System;
using namespace System::Net;
using namespace System::IO;
using namespace System::Text;
using namespace System::Collections;

// The TestAuthentication class performs the following main tasks:
// 1) It obtains the user's credentials.
// 2) Unregisters the standard Basic authentication.
// 3) Registers the customized Basic authentication.
// 4) Reads the selected page and displays it on the console.
ref class TestAuthentication
{
public:
   static String^ username;
   static String^ password;
   static String^ domain;
   static String^ uri;

   // Show how to use this program.
   static void showusage()
   {
      Console::WriteLine( "Attempts to authenticate to a URL" );
      Console::WriteLine( "\r\nUse one of the following:" );
      Console::WriteLine( "\tcustomBasicAuthentication URL username password domain" );
      Console::WriteLine( "\tcustomBasicAuthentication URL username password" );
      Console::WriteLine( "\r\nExample:" );
      Console::WriteLine( "\tcustomBasicAuthentication http://ndpue/ncl/ basicuser basic.101 ndpue" );
   }


   // Display registered authentication modules.
   static void displayRegisteredModules()
   {
      
      // The AuthenticationManager calls all authentication modules sequentially
      // until one of them responds with an authorization instance.  Show
      // the current registered modules, for testing purposes.
      IEnumerator^ registeredModules = AuthenticationManager::RegisteredModules;
      Console::WriteLine( "\r\nThe following authentication modules are now registered with the system" );
      while ( registeredModules->MoveNext() )
      {
         Console::WriteLine( "\r \n Module : {0}", registeredModules->Current );
         IAuthenticationModule^ currentAuthenticationModule = dynamic_cast<IAuthenticationModule^>(registeredModules->Current);
         Console::WriteLine( "\t  CanPreAuthenticate : {0}", currentAuthenticationModule->CanPreAuthenticate );
      }
   }


   // The getPage method accesses the selected page an displays its content
   // on the console.
   static void getPage( String^ url )
   {
      try
      {
         
         // Create the Web request object.
         HttpWebRequest^ req = dynamic_cast<HttpWebRequest^>(WebRequest::Create( url ));
         
         // Define the request access method.
         req->Method = "GET";
         
         // Define the request credentials according to the user's input.
         if ( String::Compare( domain, String::Empty ) == 0 )
                  req->Credentials = gcnew NetworkCredential( username,password ); // If the user's specifies the Internet resource domain, this usually
         else
                  req->Credentials = gcnew NetworkCredential( username,password,domain );
         
         // is by default the name of the sever hosting the resource.
         // Issue the request.
         // req->GetResponse();
         HttpWebResponse^ result = dynamic_cast<HttpWebResponse^>(req->GetResponse());
         Console::WriteLine( "\nAuthentication Succeeded:" );
         
         // Store the response.
         Stream^ sData = result->GetResponseStream();
         
         // Display the response.
         displayPageContent( sData );
      }
      catch ( WebException^ e ) 
      {
         
         // Display the error, if any. In particular display protocol
         // related error.
         if ( e->Status == WebExceptionStatus::ProtocolError )
         {
            HttpWebResponse^ hresp = dynamic_cast<HttpWebResponse^>(e->Response);
            Console::WriteLine( "\nAuthentication Failed, {0}", hresp->StatusCode );
            Console::WriteLine( "Status Code: {0}", (int)hresp->StatusCode );
            Console::WriteLine( "Status Description: {0}", hresp->StatusDescription );
            return;
         }
         Console::WriteLine( "Caught Exception: {0}", e->Message );
         Console::WriteLine( "Stack: {0}", e->StackTrace );
      }

   }


   // The displayPageContent method display the content of the
   // selected page.
   static void displayPageContent( Stream^ ReceiveStream )
   {
      
      // Create an ASCII encoding object.
      Encoding^ ASCII = Encoding::ASCII;
      
      // Define the Byte array to temporary hold the current read bytes.
      array<Byte>^read = gcnew array<Byte>(512);
      Console::WriteLine( "\r\nPage Content...\r\n" );
      
      // Read the page content and display it on the console.
      // Read the first 512 bytes.
      int bytes = ReceiveStream->Read( read, 0, 512 );
      while ( bytes > 0 )
      {
         Console::Write( ASCII->GetString( read, 0, bytes ) );
         bytes = ReceiveStream->Read( read, 0, 512 );
      }

      Console::WriteLine( "" );
   }

};


// The CustomBasic class creates a custom Basic authentication by implementing the
// IAuthenticationModule interface. In particular it performs the following
// tasks:
// 1) Defines and initializes the required properties.
// 2) Impements the Authenticate method.
public ref class CustomBasic: public IAuthenticationModule
{
private:

   String^ m_authenticationType;
   bool m_canPreAuthenticate;

public:

   // The CustomBasic constructor initializes the properties of the customized
   // authentication.
   CustomBasic()
   {
      m_authenticationType = "Basic";
      m_canPreAuthenticate = false;
   }


   property String^ AuthenticationType 
   {

      // Define the authentication type. This type is then used to identify this
      // custom authentication module. The default is set to Basic.
      virtual String^ get()
      {
         return m_authenticationType;
      }

   }

   property bool CanPreAuthenticate 
   {

      // Define the pre-authentication capabilities for the module. The default is set
      // to false.
      virtual bool get()
      {
         return m_canPreAuthenticate;
      }

   }

   // The checkChallenge method checks if the challenge sent by the HttpWebRequest
   // contains the correct type (Basic) and the correct domain name.
   // Note: the challenge is in the form BASIC REALM=S"DOMAINNAME"
   // and you must assure that the Internet Web site resides on a server whose
   // domain name is equal to DOMAINAME.
   bool checkChallenge( String^ Challenge, String^ domain )
   {
      bool challengePasses = false;
      String^ tempChallenge = Challenge->ToUpper();
      
      // Verify that this is a Basic authorization request and the requested domain
      // is correct.
      // Note: When the domain is an empty string the following code only checks
      // whether the authorization type is Basic.
      if ( tempChallenge->IndexOf( "BASIC" ) != -1 )
            if ( String::Compare( domain, String::Empty ) != 0 )
            if ( tempChallenge->IndexOf( domain->ToUpper() ) != -1 )
            challengePasses = true; // The domain is not allowed and the authorization type is Basic.
      else
            challengePasses = false;

      else
            challengePasses = true;


      return challengePasses;
   }


   // The PreAuthenticate method specifies if the authentication implemented
   // by this class allows pre-authentication.
   // Even if you do not use it, this method must be implemented to obey to the rules
   // of interface implemebtation.
   // In this case it always returns null.
   virtual Authorization^ PreAuthenticate( WebRequest^ request, ICredentials^ credentials )
   {
      return nullptr;
   }


   // 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;
   }

};


// This is the program entry point. It allows the user to enter
// her credentials and the Internet resource (Web page) to access.
// It also unregisters the standard and registers the customized basic
// authentication.
int main()
{
   array<String^>^args = Environment::GetCommandLineArgs();
   if ( args->Length < 4 )
      TestAuthentication::showusage();
   else
   {
      
      // Read the user's credentials.
      TestAuthentication::uri = args[ 1 ];
      TestAuthentication::username = args[ 2 ];
      TestAuthentication::password = args[ 3 ];
      if ( args->Length == 4 )
            TestAuthentication::domain = String::Empty; // If the domain exists, store it. Usually the domain name
      else
            TestAuthentication::domain = args[ 4 ];
      
      // is by default the name of the server hosting the Internet
      // resource.
      // Instantiate the custom Basic authentication module.
      CustomBasic^ customBasicModule = gcnew CustomBasic;
      
      // Unregister the standard Basic authentication module.
      AuthenticationManager::Unregister( "Basic" );
      
      // Register the custom Basic authentication module.
      AuthenticationManager::Register( customBasicModule );
      
      // Display registered Authorization modules.
      TestAuthentication::displayRegisteredModules();
      
      // Read the specified page and display it on the console.
      TestAuthentication::getPage( TestAuthentication::uri );
   }
}

// The following example shows how to create a custom Basic authentication module,
// how to register it using the AuthenticationManager class and how to authorize
// users to access a Web site.
// Note: To run this program you must create a test Web site that performs
// Basic authentication. Also you must add to your server machine a user whose
// credentials are the same as the ones you use in this program.
// Attention: Basic authentication sends the user's credentials over HTTP.
// Passwords and user names are encoded using Base64 encoding. Although the
// user information is encoded, it is considered insecure becasue it could be deciphered
// relatively easily.
// If you must use Basic authentication you are strongly advised to use strong
// security mechanisms, such as SSL, when transferring sensitive information.

using System;
using System.Net;
using System.IO;
using System.Text;
using System.Collections;

namespace Mssc.Services.Authentication
{
  // The TestAuthentication class performs the following main tasks:
  // 1) Obtains the user's credentials.
  // 2) Unregisters the standard Basic authentication.
  // 3) Registers the custom Basic authentication.
  // 4) Reads the selected page and displays it on the console.
  class TestAuthentication
  {

    private static string username, password, domain, uri;

    // This method invoked when the user does not enter the required input parameters.
    private static void ShowUsage()
    {
      Console.WriteLine("Attempts to authenticate to a URL");
      Console.WriteLine("\r\nUse one of the following:");
      Console.WriteLine("\tcustomBasicAuthentication URL username password domain");
      Console.WriteLine("\tcustomBasicAuthentication URL username password");
    }

    // Display registered authentication modules.
    private static void DisplayRegisteredModules()
    {
      // The AuthenticationManager calls all authentication modules sequentially
      // until one of them responds with an authorization instance.  Show
      // the current registered modules.
      IEnumerator registeredModules = AuthenticationManager.RegisteredModules;
      Console.WriteLine("\r\nThe following authentication modules are now registered with the system:");
      while(registeredModules.MoveNext())
      {
        Console.WriteLine("\r \n Module : {0}",registeredModules.Current);
        IAuthenticationModule currentAuthenticationModule = (IAuthenticationModule)registeredModules.Current;
        Console.WriteLine("\t  CanPreAuthenticate : {0}",currentAuthenticationModule.CanPreAuthenticate);
      }
    }

    // The GetPage method accesses the selected page and displays its content
    // on the console.
    private static void GetPage(String url)
    {
      try
      {
        // Create the Web request object.
        HttpWebRequest req = (HttpWebRequest) WebRequest.Create(url);

        // Define the request access method.
        req.Method = "GET";

        // Define the request credentials according to the user's input.
        if (string.IsNullOrEmpty(domain))
          req.Credentials = new NetworkCredential(username, password);
        else
          // If the user does not specify the Internet resource domain, this usually
          // is by default the name of the sever hosting the resource.
          req.Credentials = new NetworkCredential(username, password, domain);

        // Issue the request.
        using HttpWebResponse result = (HttpWebResponse) req.GetResponse();

        Console.WriteLine("\nAuthentication Succeeded:");

        // Store the response.
        Stream sData = result.GetResponseStream();

        // Display the response.
        DisplayPageContent(sData);
      }
      catch (WebException e)
      {
        // Display any errors. In particular, display any protocol-related error.
        if (e.Status == WebExceptionStatus.ProtocolError)
        {
          HttpWebResponse hresp = (HttpWebResponse) e.Response;
          Console.WriteLine("\nAuthentication Failed, " + hresp.StatusCode);
          Console.WriteLine("Status Code: " + (int) hresp.StatusCode);
          Console.WriteLine("Status Description: " + hresp.StatusDescription);
          return;
        }
        Console.WriteLine("Caught Exception: " + e.Message);
        Console.WriteLine("Stack: " + e.StackTrace);
      }
    }

    // The DisplayPageContent method display the content of the
    // selected page.
    private static void DisplayPageContent(Stream ReceiveStream)
    {
      // Create an ASCII encoding object.
      Encoding ASCII = Encoding.ASCII;

      // Define the byte array to temporarily hold the current read bytes.
      Byte[] read = new Byte[512];

      Console.WriteLine("\r\nPage Content...\r\n");

      // Read the page content and display it on the console.
      // Read the first 512 bytes.
      int bytes = ReceiveStream.Read(read, 0, 512);
      while (bytes > 0)
      {
        Console.Write(ASCII.GetString(read, 0, bytes));
        bytes = ReceiveStream.Read(read, 0, 512);
      }
      Console.WriteLine("");
    }

    // This is the program entry point. It allows the user to enter
    // her credentials and the Internet resource (Web page) to access.
    // It also unregisters the standard and registers the customized Basic
    // authentication.
    public static void Main(string[] args)
    {

      if (args.Length < 3)
            {
                ShowUsage();
            }
            else
      {

        // Read the user's credentials.
        uri = args[0];
        username = args[1];
        password = args[2];

        if (args.Length == 3)
          domain = string.Empty;
        else
          // If the domain exists, store it. Usually the domain name
          // is by default the name of the server hosting the Internet
          // resource.
          domain = args[3];

        // Instantiate the custom Basic authentication module.
        CustomBasic customBasicModule = new CustomBasic();

        // Unregister the standard Basic authentication module.
        AuthenticationManager.Unregister("Basic");

        // Register the custom Basic authentication module.
        AuthenticationManager.Register(customBasicModule);

        // Display registered authorization modules.
        DisplayRegisteredModules();

        // Read the specified page and display it on the console.
        GetPage(uri);
      }
      return;
    }
  }

  // The CustomBasic class creates a custom Basic authentication by implementing the
  // IAuthenticationModule interface. It performs the following
  // tasks:
  // 1) Defines and initializes the required properties.
  // 2) Implements the Authenticate method.

  public class CustomBasic : IAuthenticationModule
  {

    // Define the authentication type. This type is then used to identify this
    // custom authentication module. The default is set to Basic.
    public string AuthenticationType { get; } = "Basic";

    // Define the pre-authentication capabilities for the module. The default is set
    // to false.
    public bool CanPreAuthenticate { get; }

    // The CheckChallenge method checks whether the challenge sent by the HttpWebRequest
    // contains the correct type (Basic) and the correct domain name.
    // Note: The challenge is in the form BASIC REALM="DOMAINNAME";
    // the Internet Web site must reside on a server whose
    // domain name is equal to DOMAINNAME.
    public bool CheckChallenge(string challenge, string domain)
    {
      bool challengePasses = false;

      String tempChallenge = challenge.ToUpper();

      // Verify that this is a Basic authorization request and that the requested domain
      // is correct.
      // Note: When the domain is an empty string, the following code only checks
      // whether the authorization type is Basic.

      if (tempChallenge.IndexOf("BASIC") != -1)
        if (!string.IsNullOrEmpty(domain))
          if (tempChallenge.IndexOf(domain.ToUpper()) != -1)
            challengePasses = true;
          else
            // The domain is not allowed and the authorization type is Basic.
            challengePasses = false;
        else
          // The domain is a blank string and the authorization type is Basic.
          challengePasses = true;

      return challengePasses;
    }

    // The PreAuthenticate method specifies whether the authentication implemented
    // by this class allows pre-authentication.
    // Even if you do not use it, this method must be implemented to obey to the rules
    // of interface implementation.
    // In this case it always returns null.
    public Authorization PreAuthenticate(WebRequest request, ICredentials credentials)
    {
      return null;
    }

    // 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;
    }
  }
}

' The following example shows how to create a custom Basic authentication module,
' how to register it using the AuthenticationManager class and how to authorize  
' users to access a Web site.
' Note: To run this program you must create a test Web site that performs
' Basic authentication. Also you must add to your server machine a user whose
' credentials are the same as the ones you use in this program.
' Attention: Basic authentication sends the user's credentials over HTTP. 
' Passwords and user names are encoded using Base64 encoding. Although the 
' user information is encoded, it is considered insecure becasue it could be deciphered 
' relatively easily. 
' If you must use Basic authentication you are strongly advised to use strong 
' security mechanisms, such as SSL, when transferring sensitive information.


Imports System.Net
Imports System.IO
Imports System.Text
Imports System.Collections

Namespace Mssc.Services.Authentication

  Module TestingAuthentication

    ' The TestAuthentication class performs the following main tasks:
    ' 1) Obtains the user's credentials.
    ' 2) Unregisters the standard Basic authentication.
    ' 3) Registers the custom Basic authentication.
    ' 4) Reads the selected page and displays it on the console.

    Class TestAuthentication

      Private Shared username, password, domain, uri As String


      'This method invoked when the user does not enter the required input parameters.
      Private Shared Sub showusage()
        Console.WriteLine("Attempts to authenticate to a URL")
        Console.WriteLine(ControlChars.Cr + ControlChars.Lf + "Use one of the following:")
        Console.WriteLine(ControlChars.Tab + "customBasicAuthentication URL username password domain")
        Console.WriteLine(ControlChars.Tab + "customBasicAuthentication URL username password")
      End Sub


      ' Display registered authentication modules.
      Private Shared Sub displayRegisteredModules()
        ' The AuthenticationManager calls all authentication modules sequentially 
        ' until one of them responds with an authorization instance.  Show
        ' the current registered modules.
        Dim registeredModules As IEnumerator = AuthenticationManager.RegisteredModules
        Console.WriteLine(ControlChars.Cr + ControlChars.Lf + "The following authentication modules are now registered with the system:")
        While registeredModules.MoveNext()
          Console.WriteLine(ControlChars.Cr + " " + ControlChars.Lf + " Module : {0}", registeredModules.Current)
          Dim currentAuthenticationModule As IAuthenticationModule = CType(registeredModules.Current, IAuthenticationModule)
          Console.WriteLine(ControlChars.Tab + "  CanPreAuthenticate : {0}", currentAuthenticationModule.CanPreAuthenticate)
        End While
      End Sub

      ' The getPage method accesses the selected page and displays its content 
      ' on the console.
      Private Shared Sub getPage(ByVal url As [String])
        Try
          ' Create the Web request object.
          Dim req As HttpWebRequest = CType(WebRequest.Create(url), HttpWebRequest)

          ' Define the request access method.
          req.Method = "GET"

          ' Define the request credentials according to the user's input.
          If domain = [String].Empty Then
            req.Credentials = New NetworkCredential(username, password)
            ' If the user does not specify the Internet resource domain, this usually
            ' is by default the name of the sever hosting the resource.
          Else
            req.Credentials = New NetworkCredential(username, password, domain)
          End If
          ' Issue the request.
          Dim result As HttpWebResponse = CType(req.GetResponse(), HttpWebResponse)

          Console.WriteLine(ControlChars.Lf + "Authentication Succeeded:")

          ' Store the response.
          Dim sData As Stream = result.GetResponseStream()

          ' Display the response.
          displayPageContent(sData)
        Catch e As WebException
          ' Display any errors. In particular, display any protocol-related error. 
          If e.Status = WebExceptionStatus.ProtocolError Then
            Dim hresp As HttpWebResponse = CType(e.Response, HttpWebResponse)
            Console.WriteLine((ControlChars.Lf + "Authentication Failed, " + hresp.StatusCode))
            Console.WriteLine(("Status Code: " + Fix(hresp.StatusCode)))
            Console.WriteLine(("Status Description: " + hresp.StatusDescription))
            Return
          End If
          Console.WriteLine(("Caught Exception: " + e.Message))
          Console.WriteLine(("Stack: " + e.StackTrace))
        End Try
      End Sub


      ' The displayPageContent method display the content of the
      ' selected page.
      Private Shared Sub displayPageContent(ByVal ReceiveStream As Stream)
        ' Create an ASCII encoding object.
        Dim ASCII As Encoding = Encoding.ASCII

        ' Define the byte array to temporarily hold the current read bytes. 
        Dim read(511) As [Byte]

        Console.WriteLine(ControlChars.Cr + ControlChars.Lf + "Page Content..." + ControlChars.Cr + ControlChars.Lf)

        ' Read the page content and display it on the console.
        ' Read the first 512 bytes.
        Dim bytes As Integer = ReceiveStream.Read(read, 0, 512)
        While bytes > 0
          Console.Write(ASCII.GetString(read, 0, bytes))
          bytes = ReceiveStream.Read(read, 0, 512)
        End While
        Console.WriteLine("")
      End Sub

      'Entry point which delegates to C-style main Private Function
      'Public Overloads Sub Main(ByVal args() As String)
      ' Main(System.Environment.GetCommandLineArgs())
      'End Sub


      ' This is the program entry point. It allows the user to enter 
      ' her credentials and the Internet resource (Web page) to access.
      ' It also unregisters the standard and registers the customized Basic 
      ' authentication.
      Public Shared Sub Main(ByVal args() As String)

        If args.Length < 3 Then
          showusage()
        Else

          ' Read the user's credentials.
          uri = args(0)
          username = args(1)
          password = args(2)

          If args.Length = 3 Then
            domain = String.Empty
            ' If the domain exists, store it. Usually the domain name
            ' is by default the name of the server hosting the Internet
            ' resource.
          Else
            domain = args(3)
          End If

          ' Instantiate the custom Basic authentication module.
          Dim customBasicModule As New CustomBasic()

          ' Unregister the standard Basic authentication module.
          AuthenticationManager.Unregister("Basic")

          ' Register the custom Basic authentication module.
          AuthenticationManager.Register(customBasicModule)

          ' Display registered authorization modules.
          displayRegisteredModules()

          ' Read the specified page and display it on the console.
          getPage(uri)
        End If
        Return
      End Sub

    End Class

    ' The CustomBasic class creates a custom Basic authentication by implementing the
    ' IAuthenticationModule interface. It performs the following
    ' tasks:
    ' 1) Defines and initializes the required properties.
    ' 2) Implements the Authenticate and PreAuthenticate methods.

    Public Class CustomBasic
      Implements IAuthenticationModule

      Private m_authenticationType As String
      Private m_canPreAuthenticate As Boolean


      ' The CustomBasic constructor initializes the properties of the customized 
      ' authentication.
      Public Sub New()
        m_authenticationType = "Basic"
        m_canPreAuthenticate = False
      End Sub

      ' Define the authentication type. This type is then used to identify this
      ' custom authentication module. The default is set to Basic.

      Public ReadOnly Property AuthenticationType() As String _
       Implements IAuthenticationModule.AuthenticationType

        Get
          Return m_authenticationType
        End Get
      End Property

      ' Define the pre-authentication capabilities for the module. The default is set
      ' to false.

      Public ReadOnly Property CanPreAuthenticate() As Boolean _
       Implements IAuthenticationModule.CanPreAuthenticate


        Get
          Return m_canPreAuthenticate
        End Get
      End Property

    ' The checkChallenge method checks whether the challenge sent by the HttpWebRequest 
    ' contains the correct type (Basic) and the correct domain name. 
    ' Note: The challenge is in the form BASIC REALM="DOMAINNAME"; 
    ' the Internet Web site must reside on a server whose
    ' domain name is equal to DOMAINNAME.
      Public Function checkChallenge(ByVal Challenge As String, ByVal domain As String) As Boolean
        Dim challengePasses As Boolean = False

        Dim tempChallenge As [String] = Challenge.ToUpper()

        ' Verify that this is a Basic authorization request and that the requested domain
        ' is correct.
        ' Note: When the domain is an empty string, the following code only checks 
        ' whether the authorization type is Basic.
        If tempChallenge.IndexOf("BASIC") <> -1 Then
          If domain <> [String].Empty Then
            If tempChallenge.IndexOf(domain.ToUpper()) <> -1 Then
              challengePasses = True
              ' The domain is not allowed and the authorization type is Basic.
            Else
              challengePasses = False
            End If
            ' The domain is a blank string and the authorization type is Basic.
          Else
            challengePasses = True
          End If
        End If
        Return challengePasses
      End Function 'checkChallenge


      ' The PreAuthenticate method specifies whether the authentication implemented 
      ' by this class allows pre-authentication. 
      ' Even if you do not use it, this method must be implemented to obey to the rules 
      ' of interface implementation.
      ' In this case it always returns null. 
      Public Function PreAuthenticate(ByVal request As WebRequest, ByVal credentials As ICredentials) As Authorization _
          Implements IAuthenticationModule.PreAuthenticate

        Return Nothing
      End Function 'PreAuthenticate

      
      ' 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
  End Module
End Namespace

備註

AuthenticationManager 是一個靜態類別，可管理應用程式所使用的驗證模組。 當對受保護的資源提出要求時，會 AuthenticationManager 呼叫 Authenticate 方法，以取得 Authorization 在後續要求中使用的實例。

會 AuthenticationManager 呼叫 IAuthenticationModule.Authenticate 每個模組的 方法來查詢每個已註冊的驗證模組。 傳回實例的第一個 Authorization 驗證模組是用來驗證要求。

默認會向 AuthenticationManager 註冊提供基本、摘要、交涉、NTLM 和 Kerberos 驗證類型的模組。 您可以使用 方法來新增Register實作 IAuthenticationModule 介面的其他驗證模組。 驗證模組處理常式會依其加入至清單的順序進行呼叫。

屬性

CredentialPolicy	取得或設定用於資源要求 (使用 HttpWebRequest 類別所提出) 的認證原則。
CustomTargetNameDictionary	取得包含服務主要名稱 (SPN) 的字典，在使用 Kerberos 驗證要求 (使用 WebRequest 及其衍生類別所提出) 期間，這些服務主要名稱用來識別主機。
RegisteredModules	取得使用驗證管理員註冊的驗證模組清單。

方法

Authenticate(String, WebRequest, ICredentials)	已淘汰. 呼叫每個已註冊的驗證模組，找出第一個可以回應驗證要求的模組。
Equals(Object)	判斷指定的物件是否等於目前的物件。 (繼承來源 Object)
GetHashCode()	做為預設雜湊函式。 (繼承來源 Object)
GetType()	取得目前執行個體的 Type。 (繼承來源 Object)
MemberwiseClone()	建立目前 Object 的淺層複製。 (繼承來源 Object)
PreAuthenticate(WebRequest, ICredentials)	已淘汰. 預先驗證要求。
Register(IAuthenticationModule)	使用驗證管理員註冊驗證模組。
ToString()	傳回代表目前物件的字串。 (繼承來源 Object)
Unregister(IAuthenticationModule)	從登錄模組的清單移除指定的驗證模組。
Unregister(String)	從登錄模組的清單移除具有指定驗證配置的驗證模組。

另請參閱

• 3.5 SP1 版中 HTTPWebRequest 的 NTLM 驗證變更