php session原理深入理解（禁用cookie和自定义session）

一、禁用cookie缓存后如何使用session：

1、方法1

page1.php

<?php

//phpinfo();

session_start();

$_SESSION['var1']="aaaa";

$sn = session_id();

$url="<a href='page2.php?s=".$sn."'>next</a>";

echo $url;

?>

page2.php

<?php

session_id($_GET['s']);

session_start();

echo "var1:".$_SESSION['var1'];

?>

2、方法2

page1.php

<?php

session_start();

$_SESSION['var1']="aaaa";

$url="<a href='page2.php?".SID."'>next</a>"; //SID禁用cookie才会出现

echo $url;

?>

page2.php

<?php

session_id($_GET['PHPSESSID']);

session_start();

echo "var1:".$_SESSION['var1'];

?>

3、方法3

session.use_cookies = 0  //设置客户端是否使用cookie来保存session值  该参数的值不影响上述机制的进行。

session.use_only_cookies = 0  //是否只使用cookie来保存session值  该参数为1时，上述机制失效。

session.use_trans_sid = 1

page1.php

<?php

session_start();

$_SESSION['var1']="aaaa";

$url="<a href='page2.php'>next</a>";

echo $url;

?>

page2.php

<?php

session_start();

echo "var1:".$_SESSION['var1'];

?>

二、自定义方式保存session到文件 (顺序执行file1.php,file2.php,file2.php理解即可)

备注操作前请在php.ini文件中将session.save_handler = user（默认是files）,并确保session.auto_start = 0

1、session.php

<?php

/**

 * 自定义方式保存session到文件

 * 使用session_set_save_handler 函数

 * php.ini 设置

 * 默认为session.save_handler = files，必须将其修改为session.save_handler = user，即变为用户自定义方式。

 */

//在运行session_start()会执行

function open($save_path, $session_name) {//启动回话

global $sess_save_path;

$sess_save_path=$save_path;

return true;

}

//sessin_writr_close() session_destroy()

function close() {

return true;

}

//session_start() ,$_SESSION

function read($id) {//读取session

global $sess_save_path;

$sess_file=$sess_save_path."/mingc_".$id;

if (file_exists($sess_file)){

 return (string)file_get_contents($sess_file);

}else {

return false;

}

}

//结束时和sessin_writr_close()强制提交数据是$_SESSION[]="aaa";

function write($id ,$sess_data) {

global $sess_save_path;

$sess_file=$sess_save_path."/mingc_".$id;

if ($fp=fopen($sess_file, "w")){

$return=fwrite($fp, $sess_data);

fclose($fp);

return $return;

}else {

return false;

}

}

//session_destroy()

function destroy($id) {

global $sess_save_path;

$sess_file=$sess_save_path."/mingc_".$id;

return unlink($sess_file);

}

//session.gc_probability和 session.gc_divisor值决定的，open(), read() session_start也会执行gc

function gc($maxlifetime) {

global $sess_save_path;

foreach (glob($sess_save_path."/mingc_*") as $filename){

if (filemtime($filename)+$maxlifetime < time()){

unlink($filename);

}

}

return true;

}

session_set_save_handler("open", "close", "read", "write", "destroy", "gc");

session_start();

?>

2、file1.php

<?php

//原始方式  

/* 

session_start(); 

$_SESSION["username"] = "admin"; 

$_SESSION["passwd"] = 123456; 

echo session_name().'='.session_id()."<br>"; 

*/  

//session_set_save_handler 方式  

include 'session.php';  

$_SESSION["username"] = "admin"; 

$_SESSION["passwd"] = 123456; 

echo session_name().'='.session_id()."<br>";  

?>

3、file2.php

<?php

//原始方式  

/* 

session_start(); 

print_r($_SESSION); 

echo "<br>"; 

echo session_name().'='.session_id()."<br>"; 

*/  

//session_set_save_handler 方式  

include 'session.php';  

print_r($_SESSION);  

echo "<br>";  

echo session_name().'='.session_id()."<br>";  

?>

4、file3.php

<?php

//原始方式  

/* 

session_start(); 

$_SESSION = array(); 

if (isset($_COOKIE[session_name()])){ 

    setcookie(session_name(), '' , time()-100, '/'); 

} 

session_destroy(); 

echo session_name().'='.session_id()."<br>"; 

*/  

//session_set_save_handler 方式  

include 'session.php';  

$_SESSION = array();  

if (isset($_COOKIE[session_name()])){  

    setcookie(session_name(), '' , time()-100, '/');  

}  

session_destroy();  

echo session_name().'='.session_id()."<br>";  

?>

三、自定义方式保存session到数据库 

备注操作前请在php.ini文件中将session.save_handler = user（默认是files）,并确保session.auto_start = 0

1、定义数据库表

CREATE TABLE `Session` (

  `Session_Id` varchar(255) COLLATE utf8_unicode_ci NOT NULL,

  `Session_Expires` datetime NOT NULL,

  `Session_Data` text COLLATE utf8_unicode_ci,

  PRIMARY KEY (`Session_Id`)

) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

2、inc.session.php

<?php

//inc.session.php

class SysSession implements SessionHandlerInterface

{

    private $link;

    public function open($savePath, $sessionName)

    {

        $link = mysqli_connect("127.0.0.1","root","root123456","session");

        if($link){

            $this->link = $link;

            return true;

        }else{

            return false;

        }

    }

    public function close()

    {

        mysqli_close($this->link);

        return true;

    }

    public function read($id)

    {

        $result = mysqli_query($this->link,"SELECT Session_Data FROM Session WHERE Session_Id = '".$id."' AND Session_Expires > '".date('Y-m-d H:i:s')."'");

        if($row = mysqli_fetch_assoc($result)){

            return $row['Session_Data'];

        }else{

            return "";

        }

    }

    public function write($id, $data)

    {

        $DateTime = date('Y-m-d H:i:s');

        $NewDateTime = date('Y-m-d H:i:s',strtotime($DateTime.' + 1 hour'));

        $result = mysqli_query($this->link,"REPLACE INTO Session SET Session_Id = '".$id."', Session_Expires = '".$NewDateTime."', Session_Data = '".$data."'");

        if($result){

            return true;

        }else{

            return false;

        }

    }

    public function destroy($id)

    {

        $result = mysqli_query($this->link,"DELETE FROM Session WHERE Session_Id ='".$id."'");

        if($result){

            return true;

        }else{

            return false;

        }

    }

    public function gc($maxlifetime)

    {

        $result = mysqli_query($this->link,"DELETE FROM Session WHERE ((UNIX_TIMESTAMP(Session_Expires) + ".$maxlifetime.") < ".$maxlifetime.")");

        if($result){

            return true;

        }else{

            return false;

        }

    }

}

date_default_timezone_set('PRC');

$handler = new SysSession();

session_set_save_handler($handler, true);

?>

3、page1.php

<?php

//page 1

require_once('inc.session.php');

session_start();

$_SESSION['var1'] = "hello world!";

?>

4、page2.php

<?php

require_once('inc.session.php');

session_start();

if(isset($_SESSION['var1'])){

echo $_SESSION['var1'];

}

?>

参考资料：

http://php.net/manual/zh/session.constants.php

http://php.net/manual/zh/function.session-set-save-handler.php

http://blog.csdn.net/masterft/article/details/1640122

http://blog.csdn.net/wzxsjdt/article/details/50508240

http://bbs.csdn.net/topics/340097849

http://blog.csdn.net/ysydao/article/details/53234347

http://www.jb51.net/article/57177.htm