SESSION存放在数据库用法实例_php技巧

<?php/*CREATE TABLE `ws_sessions` ( `session_id` varchar(255) binary NOT NULL default '', `session_expires` int(10) unsigned NOT NULL default '0', `session_data` text, PRIMARY KEY (`session_id`)) TYPE=InnoDB;*/class session { // session-lifetime var $lifeTime; // mysql-handle var $dbHandle; function open($savePath, $sessName) { // get session-lifetime $this->lifeTime = get_cfg_var("session.gc_maxlifetime"); // open database-connection $dbHandle = @mysql_connect("localhost","root",""); $dbSel = @mysql_select_db("test",$dbHandle); // return success if(!$dbHandle || !$dbSel)  return false; $this->dbHandle = $dbHandle; return true; } function close() { $this->gc(ini_get('session.gc_maxlifetime')); // close database-connection return @mysql_close($this->dbHandle); } function read($sessID) { // fetch session-data $res = mysql_query("SELECT session_data AS d FROM ws_sessions    WHERE session_id = '$sessID'    AND session_expires > ".time(),$this->dbHandle); // return data or an empty string at failure if($row = mysql_fetch_assoc($res))  return $row['d']; return ""; } function write($sessID,$sessData) { // new session-expire-time $newExp = time() + $this->lifeTime; // is a session with this id in the database? $res = mysql_query("SELECT * FROM ws_sessions    WHERE session_id = '$sessID'",$this->dbHandle); // if yes, if(mysql_num_rows($res)) {  // ...update session-data  mysql_query("UPDATE ws_sessions    SET session_expires = '$newExp',    session_data = '$sessData'    WHERE session_id = '$sessID'",$this->dbHandle);  // if something happened, return true  if(mysql_affected_rows($this->dbHandle))  return true; } // if no session-data was found, else {  // create a new row  mysql_query("INSERT INTO ws_sessions (    session_id,    session_expires,    session_data)    VALUES(    '$sessID',    '$newExp',    '$sessData')",$this->dbHandle);  // if row was created, return true  if(mysql_affected_rows($this->dbHandle))  return true; } // an unknown error occured return false; } function destroy($sessID) { // delete session-data mysql_query("DELETE FROM ws_sessions WHERE session_id = '$sessID'",$this->dbHandle); // if session was deleted, return true, if(mysql_affected_rows($this->dbHandle))  return true; // ...else return false return false; } function gc($sessMaxLifeTime) { // delete old sessions mysql_query("DELETE FROM ws_sessions WHERE session_expires < ".time(),$this->dbHandle); // return affected rows return mysql_affected_rows($this->dbHandle); }}$session = new session();session_set_save_handler(array(&$session,"open"),    array(&$session,"close"),    array(&$session,"read"),    array(&$session,"write"),    array(&$session,"destroy"),    array(&$session,"gc"));session_start();// etc...?>

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