I was having a problem clearing all session variables, deleting the session, and creating a new session without leaving old session stuff behind in all browsers. The below code is perfect for a logout script to totally delete everything and start new. It even works in Chrome which seems to not work as other browsers when trying do logout and start a new session.
<?php
session_start();
session_unset();
session_destroy();
session_write_close();
setcookie(session_name(),'',0,'/');
session_regenerate_id(true);
?>
session_unset
(PHP 4, PHP 5, PHP 7, PHP 8)
session_unset — 全てのセッション変数を開放する
パラメータ
この関数にはパラメータはありません。
戻り値
成功した場合に true を、失敗した場合に false を返します。
注意
注意:
$_SESSION が使用されている場合、セッション変数の登録を削除するために unset() すなわち、
unset($_SESSION['varname']);を使用してください。
警告
$_SESSION スーパーグローバルを使用した
セッション変数の登録が不可能になってしまうため、
unset($_SESSION) を使って
$_SESSION を完全に unset しないでください。
注意:
session_unset() 関数は、
$_SESSION = []と同等です。
警告
この関数は、セッションがアクティブな場合にのみ動作します。
セッションが開始されていなかったり、既に破棄されている場合には、
この関数は $_SESSION 配列をクリアしません。
すべてのセッション変数をクリアする場合は、
たとえセッションがアクティブでない場合でも
$_SESSION = [] を使いましょう。
add a note
User Contributed Notes 4 notes
tim at leethost dot com ¶
12 years ago
jerry ¶
9 years ago
The difference between both session_unset and session_destroy is as follows:
session_unset just clears out the session for usage. The session is still on the users computer. Note that by using session_unset, the variable still exists. session_unset just remove all session variables. it does not destroy the session....so the session would still be active.
Using session_unset in tandem with session_destroy however, is a much more effective means of actually clearing out data. As stated in the example above, this works very well, cross browser. session_destroy is destroy the session. session_destroy() to kill all session information.....This is the more secure function to use.
Jeroen ¶
19 years ago
note to Jason: I don't know the exact mechanics of it (since I'm quite new to sessions) but I think you need to use session_unset() BEFORE you can use session_destroy() at all. I thought that session_unset() was for scripted variables, and session_destroy() just for anything saved on your side regarding the session.
zach at zkwarta dot com ¶
19 years ago
The difference between both session_unset and session_destroy is as follows:
session_unset just clears out the sesison for usage. The session is still on the users computer. Note that by using session_unset, the variable still exists.
Using session_unset in tandem with session_destroy however, is a much more effective means of actually clearing out data. As stated in the example above, this works very well, cross browser:
session_unset();
session_destroy();
I noticed that in firefox, one could simply use sesison_unset and the session would be cleared. When trying this on IE, I was horrified to find out that the data was still there, so I had to use session destroy.
