How to set session time in php? Share in two ways

Session management is very important when using PHP to write web applications. In many cases, sessions are a way to track user website operations. By default, the PHP session is destroyed after the browser is closed.

However, in many applications, the session needs to be destroyed at a specific time or after a period of user inactivity to increase website security, reduce resource consumption, etc.

PHP provides a method to set the session time. There are two ways to set the session life cycle: session.gc_maxlifetime and session.cookie_lifetime. Their differences and how to use them will be explained in detail below.

1. session.gc_maxlifetime

session.gc_maxlifetime refers to the maximum life cycle time required by the session garbage collection mechanism (that is, the survival time of the session ), which is configured in the php.ini file. By default, its value is 1440 seconds, which is 24 minutes. When the user does not perform any operations within 24 minutes, PHP's garbage collection mechanism will destroy the session. If you need to increase or decrease the session lifetime, you can modify session.gc_maxlifetime to the value you need.

For example, if you want to extend the session life cycle to 1 hour, you can set the value of session.gc_maxlifetime in php.ini to 3600 seconds:

session.gc_maxlifetime = 3600

In addition, you also You can use the ini_set function to dynamically modify the session.gc_maxlifetime value in a script, for example:

ini_set('session.gc_maxlifetime', 3600);

However, it should be noted that this value cannot be too large, otherwise it will waste server resources and cause other problems.

2. session.cookie_lifetime

##session.cookie_lifetime refers to the life cycle time of the cookie. When the cookie life cycle expires, the session will immediately be destroyed. This time is achieved by setting the expiration time of the cookie. By default, the PHP cookie life cycle is 0, that is, the cookie will be destroyed after closing the browser. If you want to extend the cookie lifetime, you can set session.cookie_lifetime to the time you need. For example, if you want to extend the cookie life cycle to 1 hour, you can set session.cookie_lifetime to 3600 seconds:

session.cookie_lifetime = 3600

Similarly, you can also use the ini_set function in a script to dynamically modify the session .cookie_lifetime value.

It should be noted that using session.cookie_lifetime to set the session life cycle time is relatively small, because in some cases, such as visiting a website that does not support cookies or disabling cookies, in the absence of cookies , PHP session cannot play a role in cross-page tracking.

Summary

In PHP, there are two methods to set the session life cycle, namely session.gc_maxlifetime and session.cookie_lifetime. The former is achieved by modifying the maximum life cycle time of the garbage collection mechanism, and the latter is achieved by setting the expiration time of the cookie. During use, choose different methods according to different application scenarios to achieve better results. At the same time, in order to increase the security and resource utilization of the website, you should set the session time reasonably.

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