PHP session advanced_PHP tutorial

php session advanced

This article mainly explains the advanced usage of session

Advanced session configuration in the php.ini configuration file:

session.save_path: session save address (original path: C:/Users/ADMINI~1/AppData/Local/Temp)
session_name: The name obtained by session
session.use_trans_sid: Enable SID support

session.gc_maxlifetime: Garbage collector, specifies the number of seconds after which data will be considered garbage and cleared

session.gc_probability=1
session.gc_divisor=100
The combination of these two is the probability of starting the gc process management
During initialization (session_start())
Probability=session.gc_probability/session.gc_divisor

session.use_cookie = 1: Whether to use cookies
session.cookie_path = '/': Cookie saving path
session.cookie_domain = '': Generally no need to change
session.cookie_lifetime = 0: long storage time

session.save_handler = files: Use files to save session information, change to user
session.save_handler=memcache: If it is memcache, then save_path=tcp://localhost:11211

1. First, change the value of session.save_handler to user (originally files) in the configuration file, and change the session data saving path to the D drive

2. Create relevant files in the root directory

session.php is a public header file, one.php is a session registration event file, two.php is a test file, and three.php is a logout file

one.php:

<!--?php
    include "session.php";
    
    $_SESSION["isLogin3"]=1;
    $_SESSION["username"]="admin";
    $_SESSION["uid"]=333;
    echo session_name().&#39;=&#39;.session_id()."<br-->";

two.php：

<!--?php
    include "session.php";
    print_r($_SESSION);
    echo &#39;<br-->&#39;;
    echo session_name().&#39;=&#39;.session_id()."
";

three.php：

<!--?php
    include "session.php";
    
    $_SESSION=array();
    if(isset($_COOKIE[session_name()])){
    	setCookie(session_name(),&#39;&#39;,time()-100,&#39;/&#39;);
    }
    session_destroy();
    echo session_name().&#39;=&#39;.session_id()."<br-->";

It is relatively important for the public header file session.php. Before doing this, in the configuration file must be changed and the value of session.serialize_handler = file must be changed to user

session.php To use the session_set_save_handler() function, check the manual for the parameters used, and then open the session

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

Then write each method according to the parameters. The focus is to grasp the execution time of each function.

open():

//在运行session_start()是调用，读取session到$_SESSION中
    function open($save_path, $session_name){
    	global $sess_save_path;   //将保存路径设置为全局变量
    	$sess_save_path=$save_path;  //读取的路径给保存路径
    	return true;
    }

close():

//session_wirte_close()和session_destroy()
    function close(){
    	return true;
    }

read():

//session_start(),$_SESSION
    //自动把session_id传进来
    function read($id){
    	global $sess_save_path;
    	$sess_file=$sess_save_path."/kf_".$id;

    	return (string)@file_get_contents($sess_file);
    }

write():

//脚本结束时和使用session_write_close()强制提交SESSION数据时
    //直接调用$_SESSION[]="aaa";
    function write($id, $sess_data){
    	global $sess_save_path;

    	//定义保存文件及文件名
    	$sess_file=$sess_save_path."/kf_".$id;
    	if($fp=@fopen($sess_file, "w")){
    		$return=fwrite($fp, $sess_data);
    		fclose($fp);
    		return $return;
    	}else{
    		return false;
    	}
    }

story() and gc(): (deletion and garbage collection)

//session_destroy()时
    function destroy($id){
    	global $sess_save_path;
    	$sess_file=$sess_save_path."/kf_".$id;

    	//删除路径对象的文件
    	return @unlink($sess_file);
    }
    //session.gc_probability和session.gc_divisor决定的，在open()和read()读数据时，
    function gc($maxlifetime){
    	global $sess_save_path;


    	//所有过期的都要删除
    	//glob遍历出所有以"/kf"的文件作为每一个文件
    	foreach(glob($sess_save_path."/kf_*") as $filename){
    		if(filetime($filename)+$maxlifetime < time()){
    			@unlink($filename);
    			echo $filename;
    		}
    	}
    	return true;
    }

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