用mysql内存表来代替php session的类

<?php
/**
@usage: use some other storage method(mysql or memcache) instead of php sessoin
@author:lein
@version:1.0
*/
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;

public function session($enginebase=null,$enginename='mysql',$storage_name='php_session'){
try{
$this->sessionexpiredtime = intval(ini_get("session.cache_expire"))*60;
}catch(exception $exception){
$this->sessionexpiredtime = 1200;
}
@session_start();
$this->sessionid=session_id();
$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->engine->refresh();
$this->engine->cleanup();
}
private function init()
{
$this->data = $this->engine->get();
if(emptyempty($this->data)&&!emptyempty($_session)){
$this->data = $_session;
$this->engine->create(false, $this->data);
}
else if(emptyempty($this->data))
{
$this->engine->create(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);
}
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 = $key;
if(emptyempty($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(!emptyempty($arr)&&is_array($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.' while date_add(time,interval '.$this->expire_time.' second)<current_timestamp()';
}else{
$sql = 'delete from '.$this->storage_name.' while time+'.$this->expire_time.'<unix_timestamp()';
}
$this->execute($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)>$this->max_session_data_length) throw new exception(__file__."->".__line__.": session data is long than max allow length(".$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>";
?>