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(PHP 4, PHP 5)
session_name — Liefert und/oder setzt den Namen der aktuellen Session
session_name() gibt den Namen der aktuellen Session zurück. Falls name angegeben wurde, aktualisiert session_name() den Namen der Session und gibt den alten Namen der Session zurück.
Der Sessionname wird auf den Ausgangswert zurückgesetzt, der zu Beginn in session.name gespeichert wurde. Deshalb muss session_name() bei jeder Anfrage aufgerufen werden (und bevor session_start() oder session_register() aufgerufen wurden).
Der Sessionname referenziert die Session-ID in Cookies und URLs. Er sollte nur alphanumerische Zeichen enthalten und sollte kurz und beschreibend sein (z.B. für Benutzer mit aktivierter Cookie-Warnung). Wenn name angegeben wird, wird der Name der aktuellen Session durch dessen Wert ersetzt.
Der Sessionname kann nicht nur aus Zahlen bestehen, sondern muss mindestens einen Buchstaben enthalten. Andernfalls wird jedesmal eine neue Session-ID erzeugt.
Gibt den Namen der aktuellen Session zurück.
Beispiel #1 session_name()-Beispiel
<?php
/* den Sessionnamen auf WebsiteID setzen */
$name_vorher = session_name ("WebsiteID");
echo "Der vorhergehende Sessionname war $name_vorher<br />";
?>
Remember, kids--you MUST use session_name() first if you want to use session_set_cookie_params() to, say, change the session timeout. Otherwise it won't work, won't give any error, and nothing in the documentation (that I've seen, anyway) will explain why.
Thanks to brandan of bildungsroman.com who left a note under session_set_cookie_params() explaining this or I'd probably still be throwing my hands up about it.
if you try to name a php session "example.com" it gets converted to "example_com" and everything breaks.
don't use a period in your session name.
Here's a sample program I made to explore the operation of the session stuff. One thing I wanted to do was switch sessions in the middle of a script - where session_name doesn't automatically create or resume the corresponding session id... (anyone have a better idea?)
<?php
if ( $_REQUEST['sname'] ) {
session_name($_REQUEST['sname']);
}
session_start();
$messages = "";
function show( $str ) { global $messages; $messages .= $str; }
function show_sess_vars() {
foreach ( $_SESSION as $key => $val ) {
show("Session var '$key': \t'$val'\n");
}
}
show("Session name: \t" . session_name() . "\n");
show("Session ID: \t" . session_id() . "\n");
foreach ( $_REQUEST as $key => $val ) {
if ( $key == 'regenerate' )
{
session_regenerate_id();
show("session_regenerate_id();\n");
show("Session name: \t" . session_name() . "\n");
show("Session ID: \t" . session_id() . "\n");
}
else if ( $key == 'clear' )
{
$_SESSION = array();
show("\$_SESSION = array();\n");
}
else if ( $key == 'switch' )
{
show("Will attempt to switch session name.. vars:\n");
show_sess_vars();
session_write_close();
$res = session_name($val);
show("session_name($val) - res: $res\n");
session_start();
show("Session name: \t" . session_name() . "\n");
show("Session ID: \t" . session_id() . "\n");
}
else if ( $key == 'switch2' )
{
show("Will attempt to switch session name.. vars:\n");
show_sess_vars();
session_write_close();
show("session_write_close();\n");
$sess_id = $_COOKIE[$val];
if ( $sess_id ) {
show("session '$val' exists, resuming..\n");
//unset($_SESSION); // to make sure - this should be reloaded below
session_name( $val );
session_id( $sess_id );
session_start(); // fills $_SESSION from the named session
} else {
show("creating new session '$val'...\n");
session_name( $val );
session_start();
session_regenerate_id(); // create new (copy of old), leave old alone
$_SESSION = array(); // wipe data clean for a fresh session
show("regenerated ID and wiped SESSION superglobal\n");
}
show("Session name: \t" . session_name() . "\n");
show("Session ID: \t" . session_id() . "\n");
}
else
{
if ( $_COOKIE[$key] ) {
show("Cookie: \t'$key': \t'$val'\n");
} else {
show("Setting session var: \t'$key': \t'$val'\n");
$_SESSION[$key] = $val;
}
}
}
show("----\nSession vars:\n");
show_sess_vars();
if ( false ) {
session_write_close();
session_name("edit_assembly");
session_start();
show("Session name: \t" . session_name() . "\n");
show("Session ID: \t" . session_id() . "\n");
show_sess_vars();
}
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html>
<head>
<title> PHP session testing </title>
<style type='text/css'>
body { background-color: gray; }
#content { background-color: white; width: 70%; margin: 1em auto 1em auto; padding: 2em;
font-family: Verdana, monospace; font-size: 10pt; }
</style>
</head>
<body>
<div id='content'>
<h1> PHP session test: </h1>
<pre><?php echo $messages; ?></pre>
</div>
</body>
</html>
You can always just use "or".
@foo or bar();
When foo fails, (and the at still means don't print an error to the browser), the function bar will be executed.
<?php
function errorhandler () { /* do something wild */ }
@session_name('mysession') or errorhandler();
?>
Another live example would be
@mysql_query('show databases') or die(mysql_error());
When the execution fails, parameter die is called (with last mysql_error as given string parameter)
One gotcha I have noticed with session_name is that it will trigger a WARNING level error if the cookie or GET/POST variable value has something other than alphanumeric characters in it. If your site displays warnings and uses PHP sessions this may be a way to enumerate at least some of your scripts:
http://example.com/foo.php?session_name_here=(bad)
Warning: session_start(): The session id contains invalid characters, valid characters are only a-z, A-Z and 0-9 in /some/path/foo.php on line 666
I did not see anything in the docs suggesting that one had to sanitize the PHP session ID values before opening the session but that appears to be the case.
Unfortunately session_name() always returns true so you have to actually get to the point of assigning variables values before you know whether you have been passed bad session data (as far as I can see). After the error has been generated in other words.
Cheers
This may sound no-brainer: the session_name() function will have no essential effect if you set session.auto_start to "true" in php.ini . And the obvious explanation is the session already started thus cannot be altered before the session_name() function--wherever it is in the script--is executed, same reason session_name needs to be called before session_start() as documented.
I know it is really not a big deal. But I had a quite hard time before figuring this out, and hope it might be helpful to someone like me.
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