1: <?php
  2: /**
  3:  * SessionHandler storage implementation that will loop through a list of
  4:  * storage drivers to handle the session information.
  5:  * This driver allows for use of caching backends on top of persistent
  6:  * backends, for example.
  7:  *
  8:  * Copyright 2010-2012 Horde LLC (http://www.horde.org/)
  9:  *
 10:  * See the enclosed file COPYING for license information (LGPL). If you
 11:  * did not receive this file, see http://www.horde.org/licenses/lgpl21.
 12:  *
 13:  * @author   Michael Slusarz <slusarz@horde.org>
 14:  * @category Horde
 15:  * @license  http://www.horde.org/licenses/lgpl21 LGPL 2.1
 16:  * @package  SessionHandler
 17:  */
 18: class Horde_SessionHandler_Storage_Stack extends Horde_SessionHandler_Storage
 19: {
 20:     /**
 21:      * Stack of storage objects.
 22:      *
 23:      * @var array
 24:      */
 25:     protected $_stack = array();
 26: 
 27:     /**
 28:      * Constructor.
 29:      *
 30:      * @param array $params  Parameters:
 31:      * <pre>
 32:      * stack - (array) [REQUIRED] A list of storage objects to loop
 33:      *         through, in order of priority. The last entry is considered
 34:      *         the "master" server.
 35:      * </pre>
 36:      *
 37:      * @throws InvalidArgumentException
 38:      */
 39:     public function __construct(array $params = array())
 40:     {
 41:         if (!isset($params['stack'])) {
 42:             throw new InvalidArgumentException('Missing stack parameter.');
 43:         }
 44: 
 45:         $this->_stack = $params['stack'];
 46:         unset($params['stack']);
 47: 
 48:         parent::__construct($params);
 49:     }
 50: 
 51:     /**
 52:      * Set the logger object.
 53:      *
 54:      * @param Horde_Log_Logger $log  The logger instance.
 55:      */
 56:     public function setLogger(Horde_Log_Logger $log)
 57:     {
 58:         parent::setLogger($log);
 59: 
 60:         foreach ($this->_stack as $ob) {
 61:             $ob->setLogger($log);
 62:         }
 63:     }
 64: 
 65:     /**
 66:      */
 67:     public function open($save_path = null, $session_name = null)
 68:     {
 69:         foreach ($this->_stack as $val) {
 70:             $val->open($save_path, $session_name);
 71:         }
 72:     }
 73: 
 74:     /**
 75:      */
 76:     public function close()
 77:     {
 78:         foreach ($this->_stack as $val) {
 79:             $val->close();
 80:         }
 81:     }
 82: 
 83:     /**
 84:      */
 85:     public function read($id)
 86:     {
 87:         foreach ($this->_stack as $val) {
 88:             $result = $val->read($id);
 89:             if ($result === false) {
 90:                 break;
 91:             }
 92:         }
 93: 
 94:         return $result;
 95:     }
 96: 
 97:     /**
 98:      */
 99:     public function write($id, $session_data)
100:     {
101:         /* Do writes in *reverse* order - it is OK if a write to one of the
102:          * non-master backends fails. */
103:         $master = true;
104: 
105:         foreach (array_reverse($this->_stack) as $val) {
106:             $result = $val->write($id, $session_data);
107:             if ($result === false) {
108:                 if ($master) {
109:                     return false;
110:                 }
111:                 /* Attempt to invalidate cache if write failed. */
112:                 $val->destroy($id);
113:             }
114:             $master = false;
115:         }
116: 
117:         return true;
118:     }
119: 
120:     /**
121:      */
122:     public function destroy($id)
123:     {
124:         /* Only report success from master. */
125:         $master = $success = true;
126: 
127:         foreach (array_reverse($this->_stack) as $val) {
128:             $result = $val->destroy($id);
129:             if ($master && ($result === false)) {
130:                 $success = false;
131:             }
132:             $master = false;
133:         }
134: 
135:         return $success;
136:     }
137: 
138:     /**
139:      */
140:     public function gc($maxlifetime = 300)
141:     {
142:         /* Only report GC results from master. */
143:         foreach ($this->_stack as $val) {
144:             $result = $val->gc($maxlifetime);
145:         }
146: 
147:         return $result;
148:     }
149: 
150:     /**
151:      */
152:     public function getSessionIDs()
153:     {
154:         /* Grab session ID list from the master. */
155:         $ob = end($this->_stack);
156:         return $ob->getSessionIDs();
157:     }
158: 
159: }
160: