Chris@0: <?php
Chris@0: 
Chris@0: /*
Chris@0:  * This file is part of the Symfony package.
Chris@0:  *
Chris@0:  * (c) Fabien Potencier <fabien@symfony.com>
Chris@0:  *
Chris@0:  * For the full copyright and license information, please view the LICENSE
Chris@0:  * file that was distributed with this source code.
Chris@0:  */
Chris@0: 
Chris@0: namespace Symfony\Component\HttpKernel;
Chris@0: 
Chris@0: /**
Chris@0:  * Signs URIs.
Chris@0:  *
Chris@0:  * @author Fabien Potencier <fabien@symfony.com>
Chris@0:  */
Chris@0: class UriSigner
Chris@0: {
Chris@0:     private $secret;
Chris@0: 
Chris@0:     /**
Chris@0:      * Constructor.
Chris@0:      *
Chris@0:      * @param string $secret A secret
Chris@0:      */
Chris@0:     public function __construct($secret)
Chris@0:     {
Chris@0:         $this->secret = $secret;
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * Signs a URI.
Chris@0:      *
Chris@0:      * The given URI is signed by adding a _hash query string parameter
Chris@0:      * which value depends on the URI and the secret.
Chris@0:      *
Chris@0:      * @param string $uri A URI to sign
Chris@0:      *
Chris@0:      * @return string The signed URI
Chris@0:      */
Chris@0:     public function sign($uri)
Chris@0:     {
Chris@0:         $url = parse_url($uri);
Chris@0:         if (isset($url['query'])) {
Chris@0:             parse_str($url['query'], $params);
Chris@0:         } else {
Chris@0:             $params = array();
Chris@0:         }
Chris@0: 
Chris@0:         $uri = $this->buildUrl($url, $params);
Chris@0: 
Chris@0:         return $uri.(false === strpos($uri, '?') ? '?' : '&').'_hash='.$this->computeHash($uri);
Chris@0:     }
Chris@0: 
Chris@0:     /**
Chris@0:      * Checks that a URI contains the correct hash.
Chris@0:      *
Chris@0:      * The _hash query string parameter must be the last one
Chris@0:      * (as it is generated that way by the sign() method, it should
Chris@0:      * never be a problem).
Chris@0:      *
Chris@0:      * @param string $uri A signed URI
Chris@0:      *
Chris@0:      * @return bool True if the URI is signed correctly, false otherwise
Chris@0:      */
Chris@0:     public function check($uri)
Chris@0:     {
Chris@0:         $url = parse_url($uri);
Chris@0:         if (isset($url['query'])) {
Chris@0:             parse_str($url['query'], $params);
Chris@0:         } else {
Chris@0:             $params = array();
Chris@0:         }
Chris@0: 
Chris@0:         if (empty($params['_hash'])) {
Chris@0:             return false;
Chris@0:         }
Chris@0: 
Chris@0:         $hash = urlencode($params['_hash']);
Chris@0:         unset($params['_hash']);
Chris@0: 
Chris@0:         return $this->computeHash($this->buildUrl($url, $params)) === $hash;
Chris@0:     }
Chris@0: 
Chris@0:     private function computeHash($uri)
Chris@0:     {
Chris@0:         return urlencode(base64_encode(hash_hmac('sha256', $uri, $this->secret, true)));
Chris@0:     }
Chris@0: 
Chris@0:     private function buildUrl(array $url, array $params = array())
Chris@0:     {
Chris@0:         ksort($params, SORT_STRING);
Chris@0:         $url['query'] = http_build_query($params, '', '&');
Chris@0: 
Chris@0:         $scheme = isset($url['scheme']) ? $url['scheme'].'://' : '';
Chris@0:         $host = isset($url['host']) ? $url['host'] : '';
Chris@0:         $port = isset($url['port']) ? ':'.$url['port'] : '';
Chris@0:         $user = isset($url['user']) ? $url['user'] : '';
Chris@0:         $pass = isset($url['pass']) ? ':'.$url['pass'] : '';
Chris@0:         $pass = ($user || $pass) ? "$pass@" : '';
Chris@0:         $path = isset($url['path']) ? $url['path'] : '';
Chris@0:         $query = isset($url['query']) && $url['query'] ? '?'.$url['query'] : '';
Chris@0:         $fragment = isset($url['fragment']) ? '#'.$url['fragment'] : '';
Chris@0: 
Chris@0:         return $scheme.$user.$pass.$host.$port.$path.$query.$fragment;
Chris@0:     }
Chris@0: }