3 * A concrete filter for validating code graphical CAPTCHAs with hashes
5 * @author Roland Haeder <webmaster@ship-simu.org>
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
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.
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.
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/>.
24 class GraphicalCodeCaptchaVerifierFilter extends BaseFilter implements Filterable {
26 * Protected constructor
30 protected function __construct () {
31 // Call parent constructor
32 parent::__construct(__CLASS__);
34 // Set part description
35 $this->setObjectDescription("A filter for verifying graphical code CAPTCHAs");
37 // Create unique ID number
38 $this->generateUniqueId();
42 * Creates an instance of this filter class
44 * @return $filterInstance An instance of this filter class
46 public final static function createGraphicalCodeCaptchaVerifierFilter () {
48 $filterInstance = new GraphicalCodeCaptchaVerifierFilter();
50 // Return the instance
51 return $filterInstance;
55 * Executes the filter with given request and response objects
57 * @param $requestInstance An instance of a class with an Requestable interface
58 * @param $responseInstance An instance of a class with an Responseable interface
61 public function execute (Requestable $requestInstance, Responseable $responseInstance) {
62 // Get the captcha code
63 $captchaCode = $requestInstance->getRequestElement('c_code');
66 if (is_null($captchaCode)) {
67 // Not set so request is invalid
68 $requestInstance->requestIsValid(false);
71 $responseInstance->addFatalMessage('captcha_code_unset');
73 // Skip further processing
75 } elseif (empty($captchaCode)) {
76 // Empty value so request is invalid
77 $requestInstance->requestIsValid(false);
80 $responseInstance->addFatalMessage('captcha_code_empty');
82 // Skip further processing
86 // Get the hash as well
87 $captchaHash = $requestInstance->getRequestElement('hash');
90 if (is_null($captchaHash)) {
91 // Not set so request is invalid
92 $requestInstance->requestIsValid(false);
95 $responseInstance->addFatalMessage('captcha_hash_unset');
97 // Skip further processing
99 } elseif (empty($captchaHash)) {
100 // Empty value so request is invalid
101 $requestInstance->requestIsValid(false);
104 $responseInstance->addFatalMessage('captcha_hash_empty');
106 // Skip further processing
110 // Now, both are set hash the given one. First get a crypto instance
111 $cryptoInstance = ObjectFactory::createObjectByConfiguredName('crypto_class');
113 // Then hash the code
114 $hashedCode = $cryptoInstance->hashString($captchaCode, $captchaHash);
116 // Is this CAPTCHA valid?
117 if ($hashedCode != $captchaHash) {
118 // Not the same so request is invalid
119 $requestInstance->requestIsValid(false);
122 $responseInstance->addFatalMessage('captcha_hash_mismatch');
123 } // END - not the same!