How to set php session time

How to set the session time in php: First open php.ini and look for the Session settings section; then set the lifetime of the Session by setting "session.gc_maxlifetime".

The operating environment of this article: windows7 system, PHP7.1 version, DELL G3 computer

php settings session (expired, invalid, Validity period)

There are many aspects of setting up a session in PHP, including setting values ​​for the session or directly setting expiration, invalidation and validity periods. The following editor will introduce to you how to use them.

Let’s first take a look at how to set the session in php.ini. Open php.ini and look for the following item in the Session settings section. The code is as follows:

   session.save_path = 
         "N;/path"
        
 
         session.save_path = 
         "C:/Temp"
         　　#此处以你自己设定的路径为准

This setting allows us to perform multi-level hashing on the session storage directory, where "N" represents the directory level to be set, and the following "/path" represents the root directory path where the session file is stored. For example, we set it to the following format, and the code is as follows:

 session.save_path = 
         "2;C:/Temp"

The above setting means that we store the php session file in two levels of directories, each level of directory is 0-9 and A total of 36 alphanumeric characters a-z are used as directory names. In this way, the directory where sessions can be stored can reach 36*36, with a total of 1332 folders. I believe this is enough for a single server. If you talk about your system architecture design To share session data among multiple servers, you can increase the directory level to 3 or more.

Session expiration time setting

Continue the Session topic in PHP. In PHP, the life cycle of the Session is mainly set by setting session.gc_maxlifetime, such as the following code :

       <?php 
        
 
         ini_set
         (
         &#39;session.gc_maxlifetime&#39;
         , 3600); 
         //设置时间 
        
 
         ini_get
         (
         &#39;session.gc_maxlifetime&#39;
         );
         //得到ini中设定值 
        
 
         ?>

[Recommended learning: PHP video tutorial]

The following provides a function encapsulated by others, but I have not tested it, only For reference, the code is as follows:

       <?php 
        
 
         function 
          start_session(
         $expire 
          = 0) 
        
 
         { 
        
 
          
         if 
          (
         $expire 
          == 0) { 
        
 
          
         $expire 
          = 
         ini_get
         (
         &#39;session.gc_maxlifetime&#39;
         ); 
        
 
          
         } 
         else 
          { 
        
 
          
         ini_set
         (
         &#39;session.gc_maxlifetime&#39;
         , 
         $expire
         ); 
        
 
          
         } 
        
 
          
         if 
          (emptyempty(
         $_COOKIE
         [
         &#39;PHPSESSID&#39;
         ])) { 
        
 
          
         session_set_cookie_params(
         $expire
         ); 
        
 
          
         session_start(); 
        
 
          
         } 
         else 
          { 
        
 
          
         session_start(); 
        
 
          
         setcookie(
         &#39;PHPSESSID&#39;
         , session_id(), time() + 
         $expire
         ); 
        
 
          
         } 
        
 
         } 
        
 
         ?>

Usage:

Join start_session(600);//Expires after 600 seconds.

Session never expires

Open the php.ini settings file and modify the three lines as follows:

1.session.use_cookies

Change this The value is set to 1, and cookies are used to pass sessionid

2 and session.cookie_lifetime

. This represents the time the SessionID is stored in the client cookie. The default is 0, which means that the SessionID will be invalidated as soon as the browser closes it. ...It is because of this that PHP sessions cannot be used permanently! So let's set it to a number we think is big, how about 999999999, that's ok! that's all.

3. session.gc_maxlifetime

This is the time that Session data is stored on the server side. If this time is exceeded, the Session data will be automatically deleted! So let's also set it to 99999999.

That's it, everything is ok. Of course, if you don't believe it, just test it and see - set up a session and come back after 10 days and a half to see if your computer is not powered off or down. , you can still see the sessionid.

Of course, it is also possible that you do not have the authority to control the server and are not as lucky as me to be able to modify the php.ini settings. We have a way to rely on ourselves. Of course, we must use the client to store cookies, right? The obtained sessionID is stored in the client's cookie, sets the value of this cookie, and then passes this value to the session_id() function. The specific method is as follows:

         <?php 
        
 
         session_start(); 
         // 启动Session 
        
 
         $_SESSION
         [
         &#39;count&#39;
         ]; 
         // 注册Session变量Count 
        
 
         isset(
         $PHPSESSID
         )?session_id(
         $PHPSESSID
         ):
         $PHPSESSID 
          = session_id(); 
        
 
         // 如果设置了$PHPSESSID，就将SessionID赋值为$PHPSESSID，否则生成SessionID 
        
 
         $_SESSION
         [
         &#39;count&#39;
         ]++; 
         // 变量count加1 
        
 
         setcookie(
         &#39;PHPSESSID&#39;
         , 
         $PHPSESSID
         , time()+3156000); 
         // 储存SessionID到Cookie中 
        
 
         echo 
          $count
         ; 
         // 显示Session变量count的值 
        
 
         ?>

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