问题

Since PHP on our server was upgraded to 7.2 from 7.0. I am getting the following warning (which leads to error) if a new deployment is done. The reason is probably, that old sessions get invalid after deployment.

Warning: session_name(): Cannot change session name when session is

active in /var/www/html/model/login/lib/Session.class.php on line 137

Warning: session_set_cookie_params(): Cannot change session cookie

parameters when session is active in

/var/www/html/model/login/lib/Session.class.php on line 138

Warning: Cannot modify header information - headers already sent by

(output started at

/var/www/html/model/login/lib/Session.class.php:137) in

/var/www/html/model/login/lib/Session.class.php on line 142

It seems like PHP 7.2 got more strict in the context of session sin a certain context. The server seems to recognize the invalid sessions and tries to destroy those. This is part of the Session class:

/**

* Secure instant destruction of session. Must be called after session_start !

*/

public static function destroyAbsolute() {

self::checkInit(); // unimportant

session_name(self::$name); // this is line 137

session_set_cookie_params(0, COOKIEPATH, null, self::$force_ssl_cookie, true);

if(session_id()) {

if (isset($_COOKIE[session_name()])) {

setcookie(session_name(), "", time() - 42000, COOKIEPATH);

}

unset($_COOKIE[session_name()]);

session_destroy();

}

}

What has changed in PHP regarding sessions?

Why is it not allowed to set a session name if another session is active (according to the docs with session_name I could change sessions and start multiple sessions)?

And how may I destroy the running session appropriately?

Doing further research I also have found the following discussion on GitHub (https://github.com/Icinga/icingaweb2/issues/3185). They confirm that this error was introduced with PHP 7.2. Unfortunatly there is also no answer :-/

回答1:

I have done a bug report at php.net and they explained that this is not a bug. Yes in PHP 7.2 a warning is generated now. However this never worked as intended, it just failed silently.

For creating multiple sessions it is required to use session_id(). Have a look at this related question: PHP How can I create multiple sessions?

session_name() as well as session_set_cookie_params() are always nonesense if the session is already running.

For the original answer have a look here: https://bugs.php.net/bug.php?id=75650&thanks=2

回答2:

I had a similar problem but finally found a way through. The code below was my first approach that gave me errors.

static function startmysession($lifetime, $path, $domain, $secure, $httponly){

session_set_cookie_params($lifetime, $path, $domain, $secure, $httponly);

session_regenerate_id(true);

if(!isset($_SESSION)){

session_start();

}

}

Now Earlier versions of php overlooked our mistake(We were practically renaming and giving a session that already exists properties which is very wrong. So how did i solve this problem?

static function startmysession($lifetime, $path, $domain, $secure, $httponly){

if(!isset($_SESSION)){

session_set_cookie_params($lifetime, $path, $domain, $secure, $httponly);

@session_regenerate_id(true);

session_start();

}

}

I now bound the session_set_cookie_params() just before session start and I test if the session already exists before doing so.

回答3:

TLDR: if the session exists, use setcookie(session_name(), session_id(), ...) else use session_set_cookie_params(...)

https://www.php.net/manual/en/function.session-set-cookie-params.php#100657

As PHP's Session Control does not handle session lifetimes correctly

when using session_set_cookie_params(), we need to do something in

order to change the session expiry time every time the user visits our

site. So, here's the problem.

$lifetime=600;

session_set_cookie_params($lifetime);

session_start();

?>

This code doesn't change the lifetime of the session when the user

gets back at our site or refreshes the page. The session WILL expire

after $lifetime seconds, no matter how many times the user requests

the page. So we just overwrite the session cookie as follows:

$lifetime=600;

session_start();

setcookie(session_name(),session_id(),time()+$lifetime);

?>

And now we have the same session cookie with the lifetime set to the

proper value.

My solution:

Originally:

$cookieParams = session_get_cookie_params();

session_set_cookie_params(

$seconds,

$cookieParams['path'],

$cookieParams['domain'],

$cookieParams['secure']

);

Now:

if(isset($_SESSION)) {

if ($seconds != 0) {

setcookie(session_name(), session_id(), time() + $seconds);

} else {

setcookie(session_name(), session_id(), $seconds);

}

} else {

$cookieParams = session_get_cookie_params();

session_set_cookie_params(

$seconds,

$cookieParams['path'],

$cookieParams['domain'],

$cookieParams['secure']

);

}

来源：https://stackoverflow.com/questions/47700336/php-7-2-warning-cannot-change-session-name-when-session-is-active