Session is passed, but $_SESSION is not

Question

I am trying to pass a graph object from jpgraph from one page to another. To pass the object to the next page, I save it as $_SESSION['graph'].

To pass the session to the next page, I add it to the URL with

echo '<a href="...../next.php?SSID='.session_id().'">Next</a>';

In next.php, I get the SID and start the session:

session_id($_GET['SSID']);
session_start();

But when I try to access $_SESSION['graph'], I get the error Undefined index: graph and subsequently, it crashed when I try to call the Stroke() function.

What am I doing wrong?

Answer 1

The default behaviour is that the session id will be stored in cookies and not in GET vars. This is controlled by the following php.ini values:

session.use_cookies=1
session.use_only_cookies=1

Which both default to 1.

So unless you have changed this, you won't need that GET var as the session id is stored in a cookie that will be passed along with request - automatically.

Just do this:

session_start(); // will get session id from cookie and resume the session
$graph = $_SESSION['graph'];