1: <?php
  2: 
  3: /**
  4:  * Wei Framework
  5:  *
  6:  * @copyright   Copyright (c) 2008-2015 Twin Huang
  7:  * @license     http://opensource.org/licenses/mit-license.php MIT License
  8:  */
  9: 
 10: namespace Wei;
 11: 
 12: /**
 13:  * Generate a URL with signature
 14:  *
 15:  * @property \Wei\Request $request
 16:  */
 17: class SafeUrl extends Base
 18: {
 19:     /**
 20:      * The token to generate the signature
 21:      *
 22:      * @var string
 23:      */
 24:     protected $token = 'wei';
 25: 
 26:     /**
 27:      * The expire seconds of signature
 28:      *
 29:      * @var int
 30:      */
 31:     protected $expireTime = 60;
 32: 
 33:     /**
 34:      * Generate signature for specified parameter names
 35:      *
 36:      * @var array
 37:      */
 38:     protected $params = array();
 39: 
 40:     /**
 41:      * Generate a URL with signature, alias of generate method
 42:      *
 43:      * @param string $url
 44:      * @return string
 45:      */
 46:     public function __invoke($url)
 47:     {
 48:         return $this->generate($url);
 49:     }
 50: 
 51:     /**
 52:      * Generate a URL with signature
 53:      *
 54:      * @param string $url
 55:      * @return string
 56:      */
 57:     public function generate($url)
 58:     {
 59:         $time = time();
 60:         $query = parse_url($url, PHP_URL_QUERY);
 61:         parse_str($query, $query);
 62: 
 63:         $query = $this->filterKeys($query, $this->params);
 64:         $query['timestamp'] = $time;
 65: 
 66:         $signature = $this->generateToken($query);
 67: 
 68:         return $url . '&timestamp=' . $time . '&signature=' . $signature;
 69:     }
 70: 
 71:     /**
 72:      * Verify whether the URL signature is OK
 73:      *
 74:      * @return bool
 75:      */
 76:     public function verify()
 77:     {
 78:         // Check if time is expired
 79:         $time = $this->request->getQuery('timestamp');
 80:         if ($this->expireTime && time() - $time > $this->expireTime) {
 81:             return false;
 82:         }
 83: 
 84:         // Remove signature parameters
 85:         $query = $this->request->getParameterReference('get');
 86:         $token = $this->request->getQuery('signature');
 87:         unset($query['signature']);
 88: 
 89:         $timestamp = $query['timestamp'];
 90: 
 91:         $query = $this->filterKeys($query, $this->params);
 92: 
 93:         $query['timestamp'] = $timestamp;
 94: 
 95:         return $this->generateToken($query) == $token;
 96:     }
 97: 
 98:     /**
 99:      * Set parameter names to generate signature
100:      *
101:      * @param string|array $params
102:      * @return $this
103:      */
104:     public function setParams($params)
105:     {
106:         $this->params = (array)$params;
107:         return $this;
108:     }
109: 
110:     /**
111:      * Generate signature by specified array
112:      *
113:      * @param array $array
114:      * @return string
115:      */
116:     protected function generateToken(array $array)
117:     {
118:         return md5(implode('|', $array) . $this->token);
119:     }
120: 
121:     /**
122:      * Removes array element by keys
123:      *
124:      * @param string $query
125:      * @param array $keys
126:      * @return array
127:      */
128:     protected function filterKeys($query, $keys)
129:     {
130:         return $keys ? array_intersect_key($query, array_flip((array)$keys)) : $query;
131:     }
132: }