1 <?php
  2 /**
  3  * Abstract base class for an authentication method
  4  *
  5  * This class is used as a base class for the different authentication
  6  * methods like {@link MemberAuthenticator} or {@link OpenIDAuthenticator}.
  7  *
  8  * @author Markus Lanthaler <markus@silverstripe.com>
  9  * @package sapphire
 10  * @subpackage security
 11  */
 12 abstract class Authenticator extends Object {
 13 
 14   /**
 15    * This variable holds all authenticators that should be used
 16    *
 17    * @var array
 18    */
 19   private static $authenticators = array('MemberAuthenticator');
 20   
 21   /**
 22    * Used to influence the order of authenticators on the login-screen
 23    * (default shows first).
 24    * 
 25    * @var string
 26    */
 27   private static $default_authenticator = 'MemberAuthenticator';
 28 
 29 
 30   /**
 31    * Method to authenticate an user
 32    *
 33    * @param array $RAW_data Raw data to authenticate the user
 34    * @param Form $form Optional: If passed, better error messages can be
 35    *                             produced by using
 36    *                             {@link Form::sessionMessage()}
 37    * @return bool|Member Returns FALSE if authentication fails, otherwise
 38    *                     the member object
 39    */
 40   public abstract static function authenticate($RAW_data,
 41                                                Form $form = null);
 42 
 43 
 44   /**
 45    * Method that creates the login form for this authentication method
 46    *
 47    * @param Controller The parent controller, necessary to create the
 48    *                   appropriate form action tag
 49    * @return Form Returns the login form to use with this authentication
 50    *              method
 51    */
 52   public abstract static function get_login_form(Controller $controller);
 53 
 54 
 55   /**
 56    * Get the name of the authentication method
 57    *
 58    * @return string Returns the name of the authentication method.
 59    */
 60   public abstract static function get_name();
 61 
 62   public static function register($authenticator) {
 63     self::register_authenticator($authenticator);   
 64   }
 65 
 66 
 67   /**
 68    * Register a new authenticator
 69    *
 70    * The new authenticator has to exist and to be derived from the
 71    * {@link Authenticator}.
 72    * Every authenticator can be registered only once.
 73    *
 74    * @param string $authenticator Name of the authenticator class to
 75    *                              register
 76    * @return bool Returns TRUE on success, FALSE otherwise.
 77    */
 78   public static function register_authenticator($authenticator) {
 79     $authenticator = trim($authenticator);
 80 
 81     if(class_exists($authenticator) == false)
 82       return false;
 83 
 84     if(is_subclass_of($authenticator, 'Authenticator') == false)
 85       return false;
 86 
 87     if(in_array($authenticator, self::$authenticators) == false) {
 88       if(call_user_func(array($authenticator, 'on_register')) === true) {
 89         array_push(self::$authenticators, $authenticator);
 90       } else {
 91         return false;
 92       }
 93     }
 94 
 95     return true;
 96   }
 97   
 98   public static function unregister($authenticator) {
 99     self::unregister_authenticator($authenticator);
100   }
101   
102     /**
103      * Remove a previously registered authenticator
104      *
105      * @param string $authenticator Name of the authenticator class to register
106      * @return bool Returns TRUE on success, FALSE otherwise.
107      */
108     public static function unregister_authenticator($authenticator) {
109         if(call_user_func(array($authenticator, 'on_unregister')) === true) {
110             if(in_array($authenticator, self::$authenticators)) {
111                 unset(self::$authenticators[array_search($authenticator, self::$authenticators)]);
112             }
113         };
114     }
115 
116 
117   /**
118    * Check if a given authenticator is registered
119    *
120    * @param string $authenticator Name of the authenticator class to check
121    * @return bool Returns TRUE if the authenticator is registered, FALSE
122    *              otherwise.
123    */
124   public static function is_registered($authenticator) {
125     return in_array($authenticator, self::$authenticators);
126   }
127 
128 
129   /**
130    * Get all registered authenticators
131    *
132    * @return array Returns an array with the class names of all registered
133    *               authenticators.
134    */
135   public static function get_authenticators() {
136     // put default authenticator first (mainly for tab-order on loginform)
137     if($key = array_search(self::$default_authenticator,self::$authenticators)) {
138         unset(self::$authenticators[$key]);
139         array_unshift(self::$authenticators, self::$default_authenticator);
140     }
141 
142     return self::$authenticators;
143   }
144   
145   /**
146    * Set a default authenticator (shows first in tabs)
147    *
148    * @param string
149    */
150   public static function set_default_authenticator($authenticator) {
151     self::$default_authenticator = $authenticator;
152     
153     
154   }
155   
156   /**
157    * @return string
158    */
159   public static function get_default_authenticator() {
160     return self::$default_authenticator;
161   }
162 
163 
164   /**
165    * Callback function that is called when the authenticator is registered
166    *
167    * Use this method for initialization of a newly registered authenticator.
168    * Just overload this method and it will be called when the authenticator
169    * is registered.
170    * <b>If the method returns FALSE, the authenticator won't be
171    * registered!</b>
172    *
173    * @return bool Returns TRUE on success, FALSE otherwise.
174    */
175   protected static function on_register() {
176     return true;
177   }
178   
179   /**
180    * Callback function that is called when an authenticator is removed.
181    *
182    * @return bool
183    */
184   protected static function on_unregister() {
185     return true;
186   }
187 }
188 
189 ?>