The solution and implementation method of session never expiring in PHP_PHP Tutorial

Make the PHP session never expire. You may not have encountered such a depressing problem, but I have encountered it and it was very depressing.

We developed a system in the early stage that can only be used by the company's customer service personnel - a limited number of customer service personnel. It was these limited customer service staff who suddenly raised this question a few days ago: every very short period of time (half an hour without operating the page), when we were anxious to solve the customer's problem, the system prompted that we needed to log in, which was delayed. Client’s time… This is not fun!

Customer is God, the only God. So the boss asked us to realize that the session in PHP never expires, unless our customer service staff artificially lets it expire. I don't understand this never-expiration behavior for security reasons; I really don't want to modify the previous program for laziness reasons. But there is no way, I still need to change.

The best way is not to modify the program, because if you modify the program, the testing department will be very depressed like me. Then you can only modify the system environment configuration. It is actually very simple. Open the php.ini setting file and modify the three lines as follows :

1. session.use_cookies

Set this value to 1 and use cookies to pass sessionid

2. session.cookie_lifetime

This represents the time that 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 is closed... It is because of this that the PHP session cannot be used permanently! Then we set it to a value that we think is very large. The number, how about 999999999, okay! That’s it.

3. session.gc_maxlifetime

This is the time that the Session data is stored on the server side. If this time is exceeded, the Session data will be automatically deleted! Then we 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. If your computer does not lose power or crash, you will still You can see this sessionid.

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

<ol class="dp-c"><li class="alt"><span><span>&lt;?php  </span></span></li><li><span>session_start(); </span><span class="comment">// 启动Session  </span><span> </span></li><li class="alt"><span class="vars">$_SESSION</span><span>[</span><span class="string">count</span><span>]; </span><span class="comment">// 注册Session变量Count  </span><span> </span></li><li><span>isset(</span><span class="vars">$PHPSESSID</span><span>)?session_id(</span><span class="vars">$PHPSESSID</span><span>):</span><span class="vars">$PHPSESSID</span><span> = session_id();   </span></li><li class="alt"><span class="comment">// 如果设置了$PHPSESSID，就将SessionID赋值为$PHPSESSID，否则生成SessionID  </span><span> </span></li><li><span>   </span></li><li class="alt"><span class="vars">$_SESSION</span><span>[</span><span class="string">count</span><span>]++; </span><span class="comment">// 变量count加1  </span><span> </span></li><li><span>setcookie(</span><span class="string">PHPSESSID</span><span>, </span><span class="vars">$PHPSESSID</span><span>, time()+3156000); </span><span class="comment">// 储存SessionID到Cookie中  </span><span> </span></li><li class="alt"><span class="func">echo</span><span> </span><span class="vars">$count</span><span>; </span><span class="comment">// 显示Session变量count的值  </span><span> </span></li><li><span>?&gt; </span></span></li></ol>

If you come back and refresh this page after a long time (how long? You can see for yourself), and the output number is 1 larger than when you left, then you are right! If it is much larger, it is estimated that someone touched your computer. This The first test is not accurate, haha... go out again for a while!

Note: The 'PHPSESSID' in the setcookie line is not certain. If you encounter a network administrator who suffers from modification mania, he may have modified it. The best way is to use phpinfo() Take a look at this function and confirm the value of session.name, which is more scientific.

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