PHP $_SESSION not working as expected

Question

I have a PHP website I'm maintaining and I've confirmed that this worked at one point.

We have a website utilizing a login system which stores a logged in user's information in a $_SESSION['user'] variable. The site used to log out the user when clicking /logout.php which essentially removed that portion of the session, then header() redirected to the homepage.

As of recently, the /logout.php file with session_start() at the top somehow doesn't see the session information when print_r() is used to output it for debugging purposes.

If I go to another page, I see the session info just fine, but not on the logout page...which is exactly why I cannot remove the session info, because it's not accessible.

I thought $_SESSION was global on the site until the browser was closed. I've never had this happen and I know the session instance was started on this page, so it's weird that it's not showing me the session data.

Any ideas? I'm totally stumped on this one!

Code: /logout.php

<?
#session_start() is inside this file
require_once($_SERVER['DOCUMENT_ROOT'].'/includes/config.php');

unset($_SESSION['user']);
header("location: /");
exit();
?>

The checking of $_SESSION['user'] is site-wide and I call to various items below it when needed for different things. Someone else built this site and I'm trying to debug why it's not working for them all of a sudden.

Answer 1

Are you accessing logout.php from the same exact domain that you set the session to begin with (i.e. example.com vs. www.example.com/logout.php)

As for just unsetting specific session data, it would be best to call session_destroy() and then unset your cookies to kill the session.

Answer 2

개인적으로 SQL 쿼리에서 공격하는 것이 좋습니다.그래서 예를 들어

SELECT 
 CASE WHEN DATEDIFF(day, GETDATE(), DateColumn) = 0 THEN SomeColumn ELSE 0 END cToday
 CASE WHEN DATEDIFF(day, GETDATE(), DateColumn) = 1 THEN SomeColumn ELSE 0 END cYesterday
 CASE WHEN DATEDIFF(day, GETDATE(), DateColumn) > 0 AND 
           DATEDIFF(day, GETDATE(), DateColumn) < 8 THEN SomeColumn ELSE 0 END cWeek
 CASE WHEN DATEDIFF(day, GETDATE(), DateColumn) > 0 THEN SomeColumn ELSE 0 END cMonth
FROM 
 SomeTable
WHERE 
 DateColumn > DATEADD(day, -28, GETDATE())

.

그렇지 않으면 SSRS 에 비슷한 접근 방식을 사용할 수 있습니다.

Answer 3

Always remember the first line of your PHP code should be session_start(); and nothing else. If all your going to do is unset the session variables and destroy the session, Try removing the require_once($_SERVER['DOCUMENT_ROOT'].'/includes/config.php'); and add the session_start() and the session_destroy() at the end of the logout.php file and see if it works.