inc/classes/main/helper/captcha/web/class_GraphicalCodeCaptcha.php

   1 <?php
   2 /**
   3  * A solveable graphical code CAPTCHA
   4  *
   5  * @author              Roland Haeder <webmaster@ship-simu.org>
   6  * @version             0.0.0
   7  * @copyright   Copyright (c) 2007, 2008 Roland Haeder, this is free software
   8  * @license             GNU GPL 3.0 or any newer version
   9  * @link                http://www.ship-simu.org
  10  *
  11  * This program is free software: you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation, either version 3 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  23  */
  24 class GraphicalCodeCaptcha extends BaseCaptcha implements SolveableCaptcha {
  25         /**
  26          * Hash of the CAPTCHA string
  27          */
  28         private $hashedString = "";
  29
  30         /**
  31          * Encrypted string
  32          */
  33         private $encryptedString = "";
  34
  35         /**
  36          * Protected constructor
  37          *
  38          * @return      void
  39          */
  40         protected function __construct () {
  41                 // Call parent constructor
  42                 parent::__construct(__CLASS__);
  43         }
  44
  45         /**
  46          * Creates an instance of this captcha class
  47          *
  48          * @param       $helperInstance         An instance of a helper class
  49          * @param       $extraInstance          An extra instance, just for better hash data
  50          * @return      $captchaInstance        An instance of this captcha class
  51          */
  52         public final static function createGraphicalCodeCaptcha (HelpableTemplate $helperInstance, FrameworkInterface $extraInstance = null) {
  53                 // Get a new instance
  54                 $captchaInstance = new GraphicalCodeCaptcha();
  55
  56                 // Set template instance
  57                 $captchaInstance->setHelperInstance($helperInstance);
  58
  59                 // Initialize the RNG
  60                 $captchaInstance->initializeRandomNumberGenerator($extraInstance);
  61
  62                 // Return the instance
  63                 return $captchaInstance;
  64         }
  65
  66         /**
  67          * Initiates the CAPTCHA
  68          *
  69          * @return      void
  70          */
  71         public function initiateCaptcha () {
  72                 // Get total length
  73                 $captchaLength = $this->getConfigInstance()->readConfig('captcha_string_length');
  74
  75                 // Get max string length
  76                 $strLength = $this->getConfigInstance()->readConfig('random_string_length');
  77
  78                 // Calculate starting position based on random place
  79                 $start = $this->getRngInstance()->randomNumber(0, ($strLength - $captchaLength));
  80
  81                 // Test it
  82                 assert($start >= 0);
  83
  84                 // Generate a random string for confirmation
  85                 $randomString = $this->getRngInstance()->randomString($strLength);
  86
  87                 // Encode the string with BASE64
  88                 $base64String = base64_encode($randomString);
  89
  90                 // Make this string a bit more readable for humans
  91                 $captchaString = substr($base64String, $start, $captchaLength);
  92
  93                 // Get all characters we want to replace
  94                 $searchChars = $this->getConfigInstance()->readConfig('captcha_search_chars');
  95
  96                 // Get fixed salt and use it as "replacement characters"
  97                 $replaceChars = $this->getRngInstance()->getExtraSalt();
  98
  99                 // Remove any plus, equals or slashes
 100                 for ($searchIdx = 0; $searchIdx < strlen($searchChars); $searchIdx++) {
 101                         // Get search character
 102                         $search = substr($searchChars, $searchIdx, 1);
 103
 104                         // Random array index
 105                         $charIdx = $this->getRngInstance()->randomNumber(0, (strlen($replaceChars) - 1));
 106
 107                         // Get replacement
 108                         $replace = substr($replaceChars, $charIdx, 1);
 109
 110                         // Replace character
 111                         $captchaString = str_replace($search, $replace, $captchaString, $captchaLength);
 112                 } // END - foreach
 113
 114                 // Get crypto instance
 115                 $cryptoInstance = ObjectFactory::createObjectByConfiguredName('crypto_class');
 116
 117                 // Hash the CAPTCHA code for later comparison
 118                 $this->hashedString = $cryptoInstance->hashString($captchaString);
 119
 120                 // Encrypt the string for later usage
 121                 $this->encryptedString = $cryptoInstance->encryptString($captchaString);
 122         }
 123
 124         /**
 125          * Render the CAPTCHA code
 126          *
 127          * @return      void
 128          */
 129         public function renderCode () {
 130                 // Get helper instance
 131                 $helperInstance = $this->getHelperInstance();
 132
 133                 // Get template instance
 134                 $templateInstance = $helperInstance->getTemplateInstance();
 135
 136                 // Load a template for this CAPTCHA
 137                 $templateInstance->loadCodeTemplate('captch_graphic_code');
 138
 139                 // Rename variable
 140                 $templateInstance->renameVariable('captcha_code', $helperInstance->getFormName().'_captcha');
 141                 $templateInstance->renameVariable('captcha_hash', $helperInstance->getFormName().'_hash');
 142                 $templateInstance->renameVariable('encrypted_code', $helperInstance->getFormName().'_encrypt');
 143
 144                 // Assign variables
 145                 $templateInstance->assignVariable($helperInstance->getFormName().'_encrypt', urlencode(base64_encode($this->encryptedString)));
 146                 $templateInstance->assignVariable($helperInstance->getFormName().'_hash', $this->hashedString);
 147
 148                 // Compile the template
 149                 $templateInstance->compileTemplate();
 150
 151                 // Get the content back
 152                 $this->addContent($templateInstance->getRawTemplateData());
 153         }
 154 }
 155
 156 // [EOF]
 157 ?>