class_GraphicalCodeCaptcha.php

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<?php
class GraphicalCodeCaptcha extends BaseCaptcha implements SolveableCaptcha {
        private $hashedString = "";

        private $encryptedString = "";

        protected function __construct () {
                // Call parent constructor
                parent::__construct(__CLASS__);
        }

        public final static function createGraphicalCodeCaptcha (HelpableTemplate $helperInstance, FrameworkInterface $extraInstance = null) {
                // Get a new instance
                $captchaInstance = new GraphicalCodeCaptcha();

                // Set template instance
                $captchaInstance->setHelperInstance($helperInstance);

                // Initialize the RNG
                $captchaInstance->initializeRandomNumberGenerator($extraInstance);

                // Return the instance
                return $captchaInstance;
        }

        public function initiateCaptcha () {
                // Get total length
                $captchaLength = $this->getConfigInstance()->readConfig('captcha_string_length');

                // Get max string length
                $strLength = $this->getConfigInstance()->readConfig('random_string_length');

                // Calculate starting position based on random place
                $start = $this->getRngInstance()->randomNumber(0, ($strLength - $captchaLength));

                // Test it
                assert($start >= 0);

                // Generate a random string for confirmation
                $randomString = $this->getRngInstance()->randomString($strLength);

                // Encode the string with BASE64
                $base64String = base64_encode($randomString);

                // Make this string a bit more readable for humans
                $captchaString = substr($base64String, $start, $captchaLength);

                // Get all characters we want to replace
                $searchChars = $this->getConfigInstance()->readConfig('captcha_search_chars');

                // Get fixed salt and use it as "replacement characters"
                $replaceChars = $this->getRngInstance()->getExtraSalt();

                // Remove any plus, equals or slashes
                for ($searchIdx = 0; $searchIdx < strlen($searchChars); $searchIdx++) {
                        // Get search character
                        $search = substr($searchChars, $searchIdx, 1);

                        // Random array index
                        $charIdx = $this->getRngInstance()->randomNumber(0, (strlen($replaceChars) - 1));

                        // Get replacement
                        $replace = substr($replaceChars, $charIdx, 1);

                        // Replace character
                        $captchaString = str_replace($search, $replace, $captchaString, $captchaLength);
                } // END - foreach

                // Get crypto instance
                $cryptoInstance = ObjectFactory::createObjectByConfiguredName('crypto_class');

                // Hash the CAPTCHA code for later comparison
                $this->hashedString = $cryptoInstance->hashString($captchaString);

                // Encrypt the string for later usage
                $this->encryptedString = $cryptoInstance->encryptString($captchaString);
        }

        public function renderCode () {
                // Get helper instance
                $helperInstance = $this->getHelperInstance();

                // Get template instance
                $templateInstance = $helperInstance->getTemplateInstance();

                // Load a template for this CAPTCHA
                $templateInstance->loadCodeTemplate('captch_graphic_code');

                // Rename variable
                $templateInstance->renameVariable('captcha_code', $helperInstance->getFormName().'_captcha');
                $templateInstance->renameVariable('captcha_hash', $helperInstance->getFormName().'_hash');
                $templateInstance->renameVariable('encrypted_code', $helperInstance->getFormName().'_encrypt');

                // Assign variables
                $templateInstance->assignVariable($helperInstance->getFormName().'_encrypt', urlencode(base64_encode($this->encryptedString)));
                $templateInstance->assignVariable($helperInstance->getFormName().'_hash', $this->hashedString);

                // Compile the template
                $templateInstance->compileTemplate();

                // Get the content back
                $this->addContent($templateInstance->getRawTemplateData());
        }
}

// [EOF]
?>