Session Class

<?php
 
	/**
	 *	@desc	Session tracking class - overrides PHP session handling
	 *	@date	14/11/05
	 *	@ver	3.2
	 *
	 *	@req	DB tables:	session {session_id[varchar32], timestamp[int11], data[text]}
	 *
	 *	@sql	CREATE TABLE `sessions` (
	 *				`sid` varchar(32) NOT NULL default '',
	 *				`timestamp` int(11) NOT NULL default '0',
	 *				`data` text NOT NULL,
	 *				PRIMARY KEY  (`sid`)
	 *			) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE latin1_general_cs;
	 */
 
	define('TIMEOUT_MINS', 20);
 
 
	class Session {
 
		var $_db;
 
		function Session() {
			session_set_save_handler(array(&$this,'_open'), array(&$this,'_close'), array(&$this,'_read'), array(&$this,'_write'), array(&$this, '_destroy'), array(&$this,'_gc'));
		}
 
		function _open($path, $name) {
			$this->_db = &Registry::GetDBConnection();
			return true;
		}
 
		function _close() {
			$this->_gc(0);
			return true;
		}
 
		function _read($sid) {
			$sql = "SELECT data FROM sessions WHERE sid = '$sid' GROUP BY sid";
			$res = $this->_db->query($sql);
			if(Pear::IsError($res)) {
				return '';
			}
 
			if($row = $res->fetchRow()) {
				return $row['data'];
			}else{
				return '';
			}
		}
 
		/**
		 *	@desc	create session or update it
		 */
		function _write($sid, $data) {
			$timestamp = time();
			$data = addslashes($data);
 
			$sql = "INSERT INTO sessions (sid, timestamp, data) VALUES ('$sid', $timestamp, '$data') ";
			$sql .= "ON DUPLICATE KEY UPDATE timestamp = $timestamp, data = '$data'";
			$res = $this->_db->query($sql);
 
			if(Pear::IsError($res)) {
				return false;
			}else{
				return true;
			}
		}
 
		function _destroy($sid) {
			$sql = "DELETE FROM sessions WHERE sid = '$sid'";
			$res = $this->_db->query($sql);
 
			if(Pear::IsError($res)) {
				return false;
			}else{
				return true;
			}
		}
 
		function _gc($life) {
			$timeout = strtotime("-" . TIMEOUT_MINS . " minutes");
			$sql = "DELETE FROM sessions WHERE timestamp < $timeout";
			$res = $this->_db->query($sql);
 
			if(Pear::IsError($res)) {
				return false;
			}else{
				return true;
			}
		}
 
 
		/**
		 *	@desc	checks whos online now
		 *			works for separate clients and pages
		 *
		 *	@return	array of results
		 */
		function check($page_id=0) {
			$timeout = time() - (TIMEOUT_MINS * 60);
 
			//load current client_id for WHERE
			$client_id = $_SESSION['client_id'];
 
			$like_clause = '%client\_id|s:%:"' . $client_id . '"';
			$like_clause .= ($page_id==0) ? "" : '%page\_id|s:%:"' . $page_id . '"';
			$like_clause .= '%';
 
			$sql = "SELECT sid, data FROM sessions ";
			$sql .= "WHERE data LIKE ";
			$sql .= " '" . $like_clause . "' ";
			$sql .= " GROUP BY sid";
 
			$rows = $this->_db->query($sql);
 
			if(Pear::IsError($res)) {
				return false;
			}else{
				//do session_decode to parse out values
				$sessions = array();
				while($row = $rows->fetchRow()) {
					$sessions[] = $this->_unserialize($row['data']);
				}
				return $sessions;
			}
		}
 
		/*
		 *
		 *	user_id|s:2:"19";client_id|s:1:"2";
		 */
		function _unserialize($session) {
			$result = array();
			$items = explode(";", $session);
			for($i=0; $i<count($items)-1; $i++) {
				$array = explode("|", $items[$i]);
				$tmp = explode(":", $array[1]);
				$value = trim($tmp[2], "\"");
				$result[$array[0]] = $value;
			}
			return $result;
		}
 
 
	}
?>