ConFoo 2025

$_SESSION

$_SESSIONSession 变量

说明

当前脚本可用 SESSION 变量的数组。更多关于如何使用的信息,参见 Session 函数 文档。

注释

注意:

“Superglobal”也称为自动化的全局变量。这就表示其在脚本的所有作用域中都是可用的。不需要在函数或方法中用 global $variable; 来访问它。

参见

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用户贡献的备注 3 notes

up
104
Tugrul
9 years ago
Creating New Session
==========================
<?php
session_start
();
/*session is started if you don't write this line can't use $_Session global variable*/
$_SESSION["newsession"]=$value;
?>
Getting Session
==========================
<?php
session_start
();
/*session is started if you don't write this line can't use $_Session global variable*/
$_SESSION["newsession"]=$value;
/*session created*/
echo $_SESSION["newsession"];
/*session was getting*/
?>
Updating Session
==========================
<?php
session_start
();
/*session is started if you don't write this line can't use $_Session global variable*/
$_SESSION["newsession"]=$value;
/*it is my new session*/
$_SESSION["newsession"]=$updatedvalue;
/*session updated*/
?>
Deleting Session
==========================
<?php
session_start
();
/*session is started if you don't write this line can't use $_Session global variable*/
$_SESSION["newsession"]=$value;
unset(
$_SESSION["newsession"]);
/*session deleted. if you try using this you've got an error*/
?>
up
11
bohwaz
16 years ago
Please note that if you have register_globals to On, global variables associated to $_SESSION variables are references, so this may lead to some weird situations.

<?php

session_start
();

$_SESSION['test'] = 42;
$test = 43;
echo
$_SESSION['test'];

?>

Load the page, OK it displays 42, reload the page... it displays 43.

The solution is to do this after each time you do a session_start() :

<?php

if (ini_get('register_globals'))
{
foreach (
$_SESSION as $key=>$value)
{
if (isset(
$GLOBALS[$key]))
unset(
$GLOBALS[$key]);
}
}

?>
up
-1
opajaap at opajaap dot nl
11 years ago
Be carefull with $_SESSION array elements when you have the same name as a normal global.

The following example leads to unpredictable behaviour of the $wppa array elements, some are updated by normal code, some not, it is totally unpredictable what happens.

<?php
global $wppa;
$wppa = array( 'elm1' => 'value1', 'elm2' => 'value2', ....etc...);

if ( !
session_id() ) @ session_start();
if ( ! isset(
$_SESSION['wppa']) $_SESSION['wppa'] = array();

if ( ! isset(
$_SESSION['wppa']['album']) ) $_SESSION['wppa']['album'] = array();
$_SESSION['wppa']['album'][1234] = 1;

$wppa['elm1'] = 'newvalue1';

print_r($_SESSION);
?>
This will most likely display Array ( [wppa] => Array ( [album] => Array ( [1234] => 1 ) [elm1] => 'newvalue1' [elm2] => 'value2' ... etc ...
But setting $wppa['elm1'] to another value or referring to it gives unpredictable results, maybe 'value1', or 'newvalue1'.

The most strange behaviour is that not all elements of $wppa[xx] show up as $_SESSION['wppa'][xx].
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