Changeset 3047

Timestamp:

07/11/2008 07:14:01 AM (5 months ago)

Author:

Geert

Message:

Captcha updates:

• Bug fix: made sure the captcha_response session cannot be overwritten too soon. The problem was that Captcha::valid() would break if you created a new Captcha instance before it. Another good example of the power of Kohana events.
  
• Added a static instance() method so Captcha::valid() can access non-static methods, e.g. the counters.
  
• Shortened method names a bit: from "valid_response" to "valid", same for counters.
  
• Added a reset_count() method.
  
• Updated the example.
  

Location:

trunk

Files:

• application/controllers/examples.php (modified) (3 diffs)
• system/libraries/Captcha.php (modified) (10 diffs)

trunk/application/controllers/examples.php

@@ -178 +178 @@
                 new Profiler;
 
-                // Ban bots after 10 invalid responses
+                // Load Captcha library
+                $captcha = new Captcha;
+
+                // Ban bots (that accept session cookies) after 50 invalid responses
                 // Be careful not to ban real people though! Set the threshold high enough.
-                if (Captcha::invalid_response_count() > 9)
+                if ($captcha->invalid_count() > 49)
                         exit('Bye! Stupid bot.');
 
@@ -187 +190 @@
                 {
                         // User has not given three valid responses yet
-                        if (Captcha::valid_response_count() < 3)
+                        if ($captcha->valid_count() < 3)
                         {
-                                // Valid response has been submitted
-                                if (Captcha::valid_response($this->input->post('captcha_response')))
+                                // Captcha::valid() is a static method that can be used as a Validation rule also
+                                if (Captcha::valid($this->input->post('captcha_response')))
                                 {
                                         echo '<p style="color:green">Good answer!</p>';
@@ -208 +211 @@
 
                 // Don't show Captcha anymore after three or more valid responses
-                if (Captcha::valid_response_count() < 3)
+                if ($captcha->valid_count() < 3)
                 {
                         echo '<p>';
-                        echo Captcha::factory()->render(); // Shows the Captcha challenge (image/riddle/etc)
+                        echo $captcha->render(); // Shows the Captcha challenge (image/riddle/etc)
                         echo '</p>';
                         echo form::input('captcha_response');

trunk/system/libraries/Captcha.php

@@ -12 +12 @@
 class Captcha_Core {
 
+        // Captcha singleton
+        protected static $instance;
+
         // Style-dependent Captcha driver
         protected $driver;
@@ -30 +33 @@
 
         /**
+         * Singleton instance of Captcha.
+         *
+         * @return  object
+         */
+        public static function instance()
+        {
+                // Create the instance if it does not exist
+                if (empty(self::$instance))
+                {
+                        self::$instance = new Captcha;
+                }
+
+                return self::$instance;
+        }
+
+        /**
          * Constructs and returns a new Captcha object.
          *
@@ -51 +70 @@
                 static $gd2_check;
 
-                // We need GD2 exclusively
+                // Check once for GD2 support
                 if ($gd2_check === NULL AND ($gd2_check = function_exists('imagegd2')) === FALSE)
                         throw new Kohana_Exception('captcha.requires_GD2');
@@ -128 +147 @@
                 self::$response = (string) $this->driver->generate_challenge();
 
-                // Store the answer in a session
+                // Store the Captcha response in a session
+                Event::add('system.post_controller', array($this, 'update_response_session'));
+
+                Log::add('debug', 'Captcha Library initialized');
+        }
+
+        /**
+         * Stores the response for the current Captcha challenge in a session so it is available
+         * on the next page load for Captcha::valid(). This method is called after controller
+         * execution (system.post_controller event) in order not to overwrite itself too soon.
+         *
+         * @return  void
+         */
+        public function update_response_session()
+        {
                 Session::instance()->set('captcha_response', sha1(strtoupper(self::$response)));
-
-                Log::add('debug', 'Captcha Library initialized');
         }
 
@@ -140 +171 @@
          * @return  boolean
          */
-        public static function valid_response($response)
+        public static function valid($response)
         {
                 // Maximum one count per page load
@@ -149 +180 @@
 
                 // Increment response counter
-                if ($counted === NULL)
+                if ($counted !== TRUE)
                 {
                         $counted = TRUE;
@@ -156 +187 @@
                         if ($result === TRUE)
                         {
-                                self::valid_response_count(Session::instance()->get('captcha_valid_response_count') + 1);
+                                self::instance()->valid_count(Session::instance()->get('captcha_valid_count') + 1);
                         }
                         // Invalid response
                         else
                         {
-                                self::invalid_response_count(Session::instance()->get('captcha_invalid_response_count') + 1);
+                                self::instance()->invalid_count(Session::instance()->get('captcha_invalid_count') + 1);
                         }
                 }
@@ -175 +206 @@
          * @return  integer  counter value
          */
-        public static function valid_response_count($new_count = NULL, $invalid = FALSE)
+        public function valid_count($new_count = NULL, $invalid = FALSE)
         {
                 // Pick the right session to use
-                $session = ($invalid === TRUE) ? 'captcha_invalid_response_count' : 'captcha_valid_response_count';
+                $session = ($invalid === TRUE) ? 'captcha_invalid_count' : 'captcha_valid_count';
 
                 // Update counter
@@ -185 +216 @@
                         $new_count = (int) $new_count;
 
-                        // Reset counter
+                        // Reset counter = delete session
                         if ($new_count < 1)
                         {
@@ -210 +241 @@
          * @return  integer  counter value
          */
-        public static function invalid_response_count($new_count = NULL)
-        {
-                return self::valid_response_count($new_count, TRUE);
+        public function invalid_count($new_count = NULL)
+        {
+                return $this->valid_count($new_count, TRUE);
+        }
+
+        /**
+         * Resets the Captcha response counters and removes the count sessions.
+         *
+         * @return  void
+         */
+        public function reset_count()
+        {
+                $this->valid_count(0);
+                $this->valid_count(0, TRUE);
         }