Experimental ElggCache

git-svn-id: https://code.elgg.org/elgg/trunk@2446 36083f99-b078-4883-b0ff-0f9b5a30f544

1 files changed, 74 insertions, 1 deletions

diff --git a/engine/lib/sessions.php b/engine/lib/sessions.php
index 02a3e06ca..bd9ce9d31 100644
--- a/engine/lib/sessions.php
+++ b/engine/lib/sessions.php
@@ -10,7 +10,76 @@
 	 * @author Curverider Ltd

 	 * @copyright Curverider Ltd 2008

 	 * @link http://elgg.org/

-	 */

+	 */
+
+	/** Elgg magic session */
+	static $SESSION;

+
+	/**
+	 * Magic session class.
+	 * This class is intended to extend the $_SESSION magic variable by providing an API hook
+	 * to plug in other values.
+	 *
+	 * Primarily this is intended to provide a way of supplying "logged in user" details without touching the session 
+	 * (which can cause problems when accessed server side).
+	 * 
+	 * If a value is present in the session then that value is returned, otherwise a plugin hook 'session::get', '$var' is called,
+	 * where $var is the variable being requested.
+	 * 
+	 * Setting values will store variables in the session in the normal way.
+	 * 
+	 * This is EXPERIMENTAL.
+	 */
+	class ElggSession implements ArrayAccess
+	{
+		/** Local cache of trigger retrieved variables */
+		private static $__localcache; 
+		
+		/** Set a value, go straight to session. */
+		function offsetSet($key, $value) { $_SESSION[$key] = $value; } 
+ 		
+		/**
+		 * Get a variable from either the session, or if its not in the session attempt to get it from
+		 * an api call.
+		 */
+ 		function offsetGet($key) 
+ 		{ 
+ 			if (isset($_SESSION[$key]))
+ 				return $_SESSION[$key];	
+ 				
+ 			if (isset($this->__localcache[$key]))
+ 				return $this->__localcache[$key];
+ 			
+ 			$value = null;
+ 			$value = trigger_plugin_hook('session::get', $key, null, $value);
+ 			
+ 			if (!$this->__localcache)
+ 				$this->__localcache = array();
+ 			
+ 			$this->__localcache[$key] = $value;
+ 			
+   			return $this->__localcache[$key];
+ 		} 
+ 		
+ 		/**
+ 		 * Unset a value from the cache and the session.
+ 		 */
+ 		function offsetUnset($key) 
+ 		{
+   			unset($this->__localcache[$key]);
+			unset($_SESSION[$key]); 
+ 		} 
+ 		
+ 		/**
+ 		 * Return whether the value is set in either the session or the cache.
+ 		 */
+ 		function offsetExists($offset) { 
+			if (isset($this->__localcache[$key]))
+				return true;
+				
+			return isset($_SESSION[$key]); 
+		}
+	}
 

 	/**

 	 * Returns whether or not the user is currently logged in

@@ -263,6 +332,10 @@
     		
     		// Register a default PAM handler
     		register_pam_handler('pam_auth_userpass');
+    		
+    		// Initialise the magic session
+    		static $SESSION;
+    		$SESSION = new ElggSession();
     		

     		return true;