一个用mysql内存表来代替php session的类

<?php 
/**
* session mysql内存表
@Usage: use some other storage method(mysql or memcache) instead of php sessoin
@author:lein
@Version:1.2
*/ 
session_start(); 
if(!isset($_SESSION['test'])){ 
 $_SESSION['test']="123_lein_".date("Y-m-d H:i:s"); 
} 
 
class session{     
    //session data 
    private $data; 
    //engine,mysql or memcache 
    private $engine; 
    //php session expire time 
    private $sessionexpiredTime; 
    //current user's session cookie value 
    private $sessionID; 
    //session coolie name 
    private $sessionCookieName; 
    public function session($engineBase=NULL,$engineName='mysql',$storage_name='php_session'){ 
        try{ 
            $this->sessionexpiredTime = intval(ini_get("session.cache_expire"))*10;//默认是180分钟，太长了，改为了30分钟 
        }catch(Exception $Exception){ 
            $this->sessionexpiredTime = 1200; 
        } 
        try{ 
            $this->sessionCookieName = ini_get("session.name"); 
        }catch(Exception $Exception){ 
            $this->sessionCookieName = 'PHPSESSID'; 
        } 
         
        if(!isset($_COOKIE[$this->sessionCookieName])){ 
            @session_start(); 
            $this->sessionID=session_id(); 
        }else{ 
            $this->sessionID=$_COOKIE[$this->sessionCookieName]; 
        } 
        $className = $engineName."SessionEngine"; 
        $this->engine = new $className( 
                                    array( 
                                          'storage_name'=>$storage_name,//mysql table name or memcahce key which stores data; 
                                          'expire_time'=>$this->sessionexpiredTime, 
                                          'data_too_long_instead_value' => '{__DATA IS *$* TO LONG__}' 
                                          ), 
                                    $this->sessionID, 
                                    &$engineBase 
                                    ); 
        $this->init(); 
        $this->loadFromSession(); 
        $this->engine->refresh(); 
        $this->engine->cleanup();      
    } 
    private function init() 
    { 
        $this->data = $this->engine->get(); 
        if(empty($this->data)){ 
            @session_start(); 
            if(!empty($_SESSION)){ 
                $this->data = $_SESSION; 
                $this->engine->create(false, $this->data); 
            } 
            else 
            { 
                $this->engine->create(false, ""); 
            } 
        } 
    } 
    public function loadFromSession($flagStartSession = false){ 
        $flag=false; 
        if($flagStartSession){ 
            @session_start(); 
        } 
        if($_SESSION&&is_array($_SESSION)){ 
            foreach($_SESSION as $k=>$v){ 
                if(!isset($this->data[$k])){ 
                    $this->data[$k] = $v; 
                    $flag=true; 
                } 
            } 
        } 
        if($flag){ 
            $this->engine->set(false, $this->data); 
        } 
    } 
    private function __get($nm) 
    { 
        if (isset($this->data[$nm])) { 
            $r = $this->data[$nm];            
            return $r; 
        }  
        else  
        { 
            return NULL; 
        } 
    } 
    private function __set($nm, $val) 
    { 
       $this->data[$nm] =  $val; 
       $this->engine->set(false, $this->data); 
    } 
     
    private function __isset($nm) 
    { 
        return isset($this->data[$nm]); 
    } 
 
    private function __unset($nm) 
    { 
        unset($this->data[$nm]); 
        $this->engine->set(false, $this->data); 
    } 
     
    function __destruct(){ 
        $this->data = NULL; 
        $this->engine->close(); 
        $this->engine = NULL; 
    } 
} 
 
interface SessionEngine 
{ 
    /*
     * set varibles
     * @param $arr array,array(varible name=>varible value,...)
     */ 
    public function setVariable($arr); 
    /*
     * get session value
     * @param $key string
     */ 
    public function get($key=""); 
    /*
     * set session value
     * @param $key string
     * @param $value string
     */ 
    public function set($key="",$value=""); 
    /*
     * set session value
     * @param $key string
     * @param $value string
     */ 
    public function create($key="",$value=""); 
    /*
     * update the session's invalid time
     * @param $key string
     */ 
    public function refresh($key=""); 
    /*
     * close mysql or memcache connection
     */ 
    public function close(); 
    /*
     * delete expired sessions
     */ 
    public function cleanup(); 
} 
 
final class mysqlSessionEngine implements SessionEngine{ 
    private $id=""; 
    private $storage_name='php_session'; 
    private $storage_name_slow='php_session_slow'; 
    private $data_too_long_instead_value = '{__DATA IS ~ TO LONG__}';//if data is longer than $max_session_data_length and you are using mysql 4 or below,insert this value into memery table instead. 
    private $expire_time=1200; 
    private $max_session_data_length = 2048; 
    private $conn; 
    private $mysql_version; 
    public function mysqlSessionEngine($arr=array(),$key="",&$_conn){ 
        $this->setVariable($arr); 
        $this->id = $key; 
        if(empty($this->id)||strlen($this->id)!=32){ 
            throw new Exception(__FILE__."->".__LINE__.": Session's cookie name can't be empty and it must have just 32 charactors!"); 
        } 
        $this->conn = $_conn; 
        if(!$this->conn||!is_resource($this->conn)){ 
            throw new Exception(__FILE__."->".__LINE__.": Need a mysql connection!"); 
        } 
        $this->mysql_version = $this->getOne("select floor(version())"); 
        if($this->mysql_version<5){ 
            $this->max_session_data_length = 255; 
        } 
    }    
    public function setVariable($arr){ 
        if(!empty($arr)&&is_array($arr)){ 
            foreach($arr as $k=>$v){ 
                $this->$k = $v;               
                if($k=='storage_name'){ 
                    $this->storage_name_slow = $v.'_slow'; 
                } 
            } 
        } 
    } 
    public function get($key=""){ 
        if($key=="") $key = $this->id; 
        $return = $this->getOne('select value from '.$this->storage_name.' where id="'.$key.'"'); 
        if($return==$this->data_too_long_instead_value) 
        { 
            $return = $this->getOne('select value from '.$this->storage_name_slow.' where id="'.$key.'"'); 
        } 
        if(!$return) 
        { 
            $mysqlError = mysql_error($this->conn); 
            if(strpos($mysqlError,"doesn't exist")!==false) 
            { 
                $this->initTable(); 
            } 
            $return = array(); 
        } 
        else 
        { 
            $return = unserialize($return); 
        } 
        return $return; 
    } 
    public function close(){ 
        @mysql_close($this->conn); 
    } 
    public function cleanup(){ 
        if($this->mysql_version>4){ 
            $sql = 'delete from '.$this->storage_name.' where date_add(`time`,INTERVAL '.$this->expire_time.' SECOND)<CURRENT_TIMESTAMP()'; 
        }else{ 
            $sql = 'delete from '.$this->storage_name_slow.' where `time`+'.$this->expire_time.'<unix_timestamp()'; 
            if($_SESSION['username']=="leinchu"){ 
                echo $sql; 
            } 
            $this->execute($sql); 
            $sql = 'delete from '.$this->storage_name.' where `time`+'.$this->expire_time.'<unix_timestamp()'; 
            if($_SESSION['username']=="leinchu"){ 
                echo $sql; 
            } 
        } 
        $this->execute($sql); 
    } 
    public function refresh($key=""){ 
        if($this->mysql_version>4){ 
            $sql = 'update '.$this->storage_name.' set `time`=CURRENT_TIMESTAMP() where id="'.$key.'"'; 
        }else{ 
            $sql = 'update '.$this->storage_name.' set `time`=unix_timestamp() where id="'.$key.'"'; 
        } 
        $return = $this->execute($sql); 
        if(!$return){ 
            $this->initTable(); 
            $return = $this->execute($sql,true); 
        } 
        return $return; 
    } 
    public function create($key="",$value=""){ 
        if($key=="") $key = $this->id; 
        if($value != "") $value = mysql_real_escape_string(serialize($value),$this->conn); 
        if(strlen($value)>$this->max_session_data_length) 
        { 
            if($this->mysql_version>4){ 
                throw new Exception(__FILE__."->".__LINE__.": Session data is long than max allow length(".$this->max_session_data_length.")!"); 
            } 
        } 
        if($this->mysql_version>4){ 
            $sql = 'replace into '.$this->storage_name.' set value=/''.$value.'/',id="'.$key.'",`time`=CURRENT_TIMESTAMP()'; 
        }else{ 
            $sql = 'replace into '.$this->storage_name.' set value=/''.$value.'/',id="'.$key.'",`time`=unix_timestamp()'; 
        } 
        $return = $this->execute($sql); 
        if(!$return){ 
            $this->initTable(); 
            $return = $this->execute($sql,true); 
        } 
        return $return; 
    } 
    public function set($key="",$value=""){      
        if($key=="") $key = $this->id; 
        if($value != "") $value = mysql_real_escape_string(serialize($value),$this->conn); 
        $sql = 'update '.$this->storage_name.' set value=/''.$value.'/' where id="'.$key.'"'; 
        if(strlen($value)>$this->max_session_data_length) 
        { 
            if($this->mysql_version>4){ 
                throw new Exception(__FILE__."->".__LINE__.": Session data is long than max allow length(".$this->max_session_data_length.")!"); 
            } 
            $sql = 'replace into '.$this->storage_name_slow.' set value=/''.$value.'/',id="'.$key.'",`time`=unix_timestamp()'; 
            $this->execute($sql,true); 
            $sql = 'update '.$this->storage_name.' set value=/''.$this->data_too_long_instead_value.'/' where id="'.$key.'"';  
        } 
        $return = $this->execute($sql); 
        if(!$return){ 
            $this->initTable(); 
            $return = $this->execute($sql,true); 
        } 
        return $return; 
    } 
    private function initTable(){        
        if($this->mysql_version>4){ 
            $sql = " 
                CREATE TABLE if not exists `".$this->storage_name."` ( 
                  `id` char(32) NOT NULL default 'ERR', 
                  `value` VARBINARY(".$this->max_session_data_length.") NULL, 
                  `time` timestamp NOT NULL default CURRENT_TIMESTAMP on update CURRENT_TIMESTAMP, 
                  PRIMARY KEY  (`id`), 
                  KEY `time` (`time`) 
                ) ENGINE=MEMORY; 
                "; 
        }else{           
            $sqlSlow = " 
                CREATE TABLE if not exists `".$this->storage_name."_slow` ( 
                  `id` char(32) NOT NULL default 'ERR', 
                  `value` text NULL, 
                  `time` int(10) not null default '0', 
                  PRIMARY KEY  (`id`), 
                  KEY `time` (`time`) 
                ) ENGINE=MyISAM; 
                "; 
            $this->execute($sqlSlow,true); 
             
            $sql = " 
                CREATE TABLE if not exists `".$this->storage_name."` ( 
                  `id` char(32) NOT NULL default 'ERR', 
                  `value` VARCHAR(255) NULL, 
                  `time` int(10) not null default '0', 
                  PRIMARY KEY  (`id`), 
                  KEY `time` (`time`) 
                ) ENGINE=MEMORY; 
                "; 
        } 
        return $this->execute($sql,true); 
    } 
    private function execute($sql,$die=false) 
    { 
        if($die) 
        { 
            mysql_query($sql,$this->conn) or die("exe Sql error:<br>".mysql_error()."<br>".$sql."<hr>");            
        } 
        else 
        { 
            mysql_query($sql,$this->conn); 
            if(mysql_error()){ 
                return false; 
            }else{ 
                return true; 
            } 
        } 
    } 
    private function getOne($sql,$die=false){ 
        $rs = $this->query($sql,$die); 
        if($rs && ($one = mysql_fetch_row($rs)) ){ 
            return $one[0]; 
        }else{ 
            return false; 
        } 
    } 
    private function query($sql,$die=false){ 
        if($die) 
            $rs = mysql_query($sql,$this->conn) or die("query Sql error:<br>".mysql_error()."<br>".$sql."<hr>"); 
        else 
            $rs = mysql_query($sql,$this->conn); 
        return $rs; 
    } 
} 
$lnk = mysql_connect('localhost', 'root', '123456') 
       or die ('Not connected : ' . mysql_error()); 
 
// make foo the current db 
mysql_select_db('test', $lnk) or die ('Can/'t use foo : ' . mysql_error()); 
$S = new session($lnk); 
if(!$S->last){ 
 $S->last = time(); 
} 
echo "First visit at ".$S->last."<br>"; 
if(!$S->lastv){ 
 $S->lastv = 0; 
} 
$S->lastv++; 
echo "lastv=".$S->lastv."<br>"; 
echo "test=".$S->test."<br>"; 
if(isset($_GET['max'])){ 
 $S->boom = str_repeat("OK",255);  
} 
if(isset($_GET['boom'])){ 
 $S->boom = $_GET['boom'];  
} 
echo "boom=".$S->boom."<br>"; 
?>