PHP 5.6.0beta1 released

$_SESSION

$HTTP_SESSION_VARS [非推奨]

(PHP 4 >= 4.1.0, PHP 5)

$_SESSION -- $HTTP_SESSION_VARS [非推奨]セッション変数

説明

現在のスクリプトで使用できるセッション変数を含む連想配列です。 セッション変数の使用法についての詳細は、 セッション関数 のドキュメントを参照ください。

$HTTP_SESSION_VARS は同じ情報を格納していますが、 これはスーパーグローバルではありません ($HTTP_SESSION_VARS$_SESSION は異なる変数であり、PHP はこれらを異なる変数として扱うことに注意してください)。

変更履歴

バージョン 説明
4.1.0 $_SESSION が導入され、 $HTTP_SESSION_VARS は非推奨となりました。

注意

注意:

これは 'スーパーグローバル' あるいは自動グローバル変数と呼ばれるものです。 スクリプト全体を通してすべてのスコープで使用することができます。 関数やメソッドの内部で使用する場合にも global $variable; とする必要はありません。

参考

  • session_start() - 新しいセッションを開始、あるいは既存のセッションを再開する

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User Contributed Notes 9 notes

up
7
bohwaz
5 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
2
Miller
8 months ago
I wrote a little page for controlling/manipulating the session. Obviously, never use this on a production server, but I use it on my localhost to assist me in checking and changing session values on the fly.

Again, it makes use of eval() and exposes the session, so never use this on a web server.

<?php
error_reporting
(E_ALL);
session_start();
if (isset(
$_POST['session'])) {
   
$session = eval("return {$_POST['session']};");
    if (
is_array($session)) {
       
$_SESSION = $session;
       
header("Location: {$_SERVER['PHP_SELF']}?saved");
    }
    else {
       
header("Location: {$_SERVER['PHP_SELF']}?error");
    }
}

$session = htmlentities(var_export($_SESSION, true));
?>
<!DOCTYPE html>
<html lang="en-US">
    <head>
        <meta charset="UTF-8">
        <title>Session Variable Management</title>
        <style>
            textarea { font: 12px Consolas, Monaco, monospace; padding: 2px; border: 1px solid #444444; width: 99%; }
            .saved, .error { border: 1px solid #509151; background: #DDF0DD; padding: 2px; }
            .error { border-color: #915050; background: #F0DDDD; }
        </style>
    </head>
    <body>
        <h1>Session Variable Management</h1>
<?php if (isset($_GET['saved'])) { ?>
        <p class="saved">The session was saved successfully.</p>
<?php } else if (isset($_GET['error'])) { ?>
        <p class="error">The session variable did not parse correctly.</p>
<?php } ?>
        <form method="post">
            <textarea name="session" rows="<?php echo count(preg_split("/\n|\r/", $session)); ?>"><?php echo $session; ?></textarea>
            <input type="submit" value="Update Session">
        </form>
    </body>
</html>
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1
charlese at cvs dot com dot au
4 years ago
I was having troubles with session variables working in some environments and being seriously flaky in others. I was using $_SESSION as an array. It works properly when I used $_SESSION as pointers to arrays. As an example the following code works in some environments and not others.

<?php
//Trouble if I treate $form_convert and $_SESSION['form_convert'] as unrelated items
$form_convert=array();
if (isset(
$_SESSION['form_convert'])){
       
$form_convert=$_SESSION['form_convert'];
    }
}
?>
The following works well.
<?php
if (isset($_SESSION['form_convert'])){
   
$form_convert = $_SESSION['form_convert'];
}else{
   
$form_convert = array();
   
$_SESSION['form_convert']=$form_convert;
}
?>
up
-1
Fred
7 months ago
Regarding array keys, from http://php.net/manual/en/language.types.array.php, "Strings containing valid integers will be cast to the integer type".

The manual on $_SESSION says "An associative array". So an associative array is expected literally...? It does no one any good if this bit of important info about accessing and storing session data remains buried in manual comments.

Session variables with a single number will not work, however "1a" will work, as will "a1" and even a just single letter, for example "a" will also work.

(Invalid)
1st page

<?php
session_start
();
$_SESSION["1"] = "LOGGED";
?>

2nd page

<?php
session_start
();
echo
$_SESSION["1"];
?>

---------------------------------------------------------------

(Valid)
1st page

<?php
session_start
();
$_SESSION["a"] = "LOGGED";
?>

2nd page

<?php
session_start
();
echo
$_SESSION["a"];
?>

---------------------------------------------------------------

(Valid)
1st page

<?php
session_start
();
$_SESSION["a1"] = "LOGGED";
?>

2nd page

<?php
session_start
();
echo
$_SESSION["a1"];
?>

---------------------------------------------------------------

Example from PHP.net manual on Session variables

<?php
$_SESSION
[1][1] = 'cake'; // fails

$_SESSION['v1'][2] = 'cake'; // works
?>

Source: http://php.net/manual/en/language.types.array.php
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-2
pike-php at kw dot nl
3 years ago
When accidently assigning a unset variable to $_SESSION, like

   $_SESSION['foo'] = $bar

while $bar was not defined, I got the following error message:

"Warning: Unknown(): Your script possibly relies on a session side-effect which existed until PHP 4.2.3. Please be advised that the session extension does not consider global variables as a source of data, unless register_globals is enabled. "

The errormessage was quite unrelated and got me off-track. The real error was, $bar was not defined.
up
-3
Steve Clay
5 years ago
Unlike a real PHP array, $_SESSION keys at the root level must be valid variable names.

<?php
$_SESSION
[1][1] = 'cake'; // fails

$_SESSION['v1'][1] = 'cake'; // works
?>

I imagine this is an internal limitation having to do with the legacy function session_register(), where the registered global var must similarly have a valid name.
up
-7
opajaap at opajaap dot nl
7 months 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].
up
-8
Dave
4 years ago
If you deploy php code and cannot control whether register_globals is off, place this snippet in your code to prevent session injections:

<?php
if (isset($_REQUEST['_SESSION'])) die("Get lost Muppet!");
?>
up
-11
jherry at netcourrier dot com
5 years ago
You may have trouble if you use '|' in the key:

$_SESSION["foo|bar"] = "fuzzy";

This does not work for me. I think it's because the serialisation of session object is using this char so the server reset your session when it cannot read it.

To make it work I replaced '|' by '_'.
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