How do I reopen a session in PHP without getting header already sent warnings?
After setting all the session vars I like to set, I close the session with session_write_close(). I do this, because as long as the session is open, there may be only one active connection from the same client. But I like to have multiple parallel ones.
However if I like to set another session variable at a later point, I need to reopen the session with session_start() once again. This works, but as I already send code to the client it prints "headers already sent"-warnings. Why is it trying to set the cookie again? The cookie is already set. Only thing I need is to gain access to writing the session files on the server again.
Well, I can suppress them. But is there a way of reopening a session, that has been closed with session_write_close without re-sending the Cookie-header? The Cookie-header is already sent correctly by the first session_start(). So the second one just needs to give me back access to writing to the session files stored on the web server.
<?php
session_start();
// setting all the session vars I like to set
session_write_close(); // <-- // To allow parallel requests by the same user, while this script is still running
// Code that takes some time to execute
// It also prints output, so no more cookie headers after this point
@session_start(); // <-- works, but I like to use it without suppressing warnings
$_SESSION['key'] = 'new value I like to store';
session_write_close();
?>
session_start();
...
session_write_close();
...
ini_set('session.use_only_cookies', false);
ini_set('session.use_cookies', false);
ini_set('session.use_trans_sid', false);
ini_set('session.cache_limiter', null);
session_start(); // second session_start
This will prevent php from calling php_session_send_cookie() a second time.
See it working.
Though restructuring the scripts still seems to be the better option...
For PHP 7.2+, you will basically need to re-implement session cookies to avoid errors and warnings:
ini_set('session.use_only_cookies', false);
ini_set('session.use_cookies', false);
ini_set('session.use_trans_sid', false);
ini_set('session.cache_limiter', null);
if(array_key_exists('PHPSESSID', $_COOKIE))
session_id($_COOKIE['PHPSESSID']);
else {
session_start();
setcookie('PHPSESSID', session_id());
session_write_close();
}
session_start();
...
session_write_close();
...
session_start(); // second session_start