1: <?php
  2: /**
  3:  * Magic session class.
  4:  * This class is intended to extend the $_SESSION magic variable by providing an API hook
  5:  * to plug in other values.
  6:  *
  7:  * Primarily this is intended to provide a way of supplying "logged in user"
  8:  * details without touching the session (which can cause problems when
  9:  * accessed server side).
 10:  *
 11:  * If a value is present in the session then that value is returned, otherwise
 12:  * a plugin hook 'session:get', '$var' is called, where $var is the variable
 13:  * being requested.
 14:  *
 15:  * Setting values will store variables in the session in the normal way.
 16:  *
 17:  * LIMITATIONS: You can not access multidimensional arrays
 18:  *
 19:  * @package    Elgg.Core
 20:  * @subpackage Sessions
 21:  */
 22: class ElggSession implements ArrayAccess {
 23:     /** Local cache of trigger retrieved variables */
 24:     private static $__localcache;
 25: 
 26:     /**
 27:      * Test if property is set either as an attribute or metadata.
 28:      *
 29:      * @param string $key The name of the attribute or metadata.
 30:      *
 31:      * @return bool
 32:      */
 33:     function __isset($key) {
 34:         return $this->offsetExists($key);
 35:     }
 36: 
 37:     /**
 38:      * Set a value, go straight to session.
 39:      *
 40:      * @param string $key   Name
 41:      * @param mixed  $value Value
 42:      *
 43:      * @return void
 44:      */
 45:     function offsetSet($key, $value) {
 46:         $_SESSION[$key] = $value;
 47:     }
 48: 
 49:     /**
 50:      * Get a variable from either the session, or if its not in the session
 51:      * attempt to get it from an api call.
 52:      *
 53:      * @see ArrayAccess::offsetGet()
 54:      *
 55:      * @param mixed $key Name
 56:      *
 57:      * @return mixed
 58:      */
 59:     function offsetGet($key) {
 60:         if (!ElggSession::$__localcache) {
 61:             ElggSession::$__localcache = array();
 62:         }
 63: 
 64:         if (isset($_SESSION[$key])) {
 65:             return $_SESSION[$key];
 66:         }
 67: 
 68:         if (isset(ElggSession::$__localcache[$key])) {
 69:             return ElggSession::$__localcache[$key];
 70:         }
 71: 
 72:         $value = NULL;
 73:         $value = elgg_trigger_plugin_hook('session:get', $key, NULL, $value);
 74: 
 75:         ElggSession::$__localcache[$key] = $value;
 76: 
 77:         return ElggSession::$__localcache[$key];
 78:     }
 79: 
 80:     /**
 81:      * Unset a value from the cache and the session.
 82:      *
 83:      * @see ArrayAccess::offsetUnset()
 84:      *
 85:      * @param mixed $key Name
 86:      *
 87:      * @return void
 88:      */
 89:     function offsetUnset($key) {
 90:         unset(ElggSession::$__localcache[$key]);
 91:         unset($_SESSION[$key]);
 92:     }
 93: 
 94:     /**
 95:      * Return whether the value is set in either the session or the cache.
 96:      *
 97:      * @see ArrayAccess::offsetExists()
 98:      *
 99:      * @param int $offset Offset
100:      *
101:      * @return bool
102:      */
103:     function offsetExists($offset) {
104:         if (isset(ElggSession::$__localcache[$offset])) {
105:             return true;
106:         }
107: 
108:         if (isset($_SESSION[$offset])) {
109:             return true;
110:         }
111: 
112:         if ($this->offsetGet($offset)) {
113:             return true;
114:         }
115: 
116:         return false;
117:     }
118: 
119: 
120:     /**
121:      * Alias to ::offsetGet()
122:      *
123:      * @param string $key Name
124:      *
125:      * @return mixed
126:      */
127:     function get($key) {
128:         return $this->offsetGet($key);
129:     }
130: 
131:     /**
132:      * Alias to ::offsetSet()
133:      *
134:      * @param string $key   Name
135:      * @param mixed  $value Value
136:      *
137:      * @return void
138:      */
139:     function set($key, $value) {
140:         $this->offsetSet($key, $value);
141:     }
142: 
143:     /**
144:      * Alias to offsetUnset()
145:      *
146:      * @param string $key Name
147:      *
148:      * @return void
149:      */
150:     function del($key) {
151:         $this->offsetUnset($key);
152:     }
153: }
154: