PHP: Possible reasons for $_SESSION['var'] to be mysteriously undefined with flash upload

Question

I am having trouble with a session id not being defined.

The session variable is being called on a page that a form posts to via an ajax/jquery query.

The session variable is called on every other page without a problem. The variable is set when a user logs in, and is checked by an auth.php file. The auth.php file finds the session variable just fine, however, the insert.php file spits out an error: "Undefined index: var....".

Is there a reason for a session variable to get lost?

EDIT: I am calling session_start in my auth.php file. I get an error message if I try to start another session.

Is it possible that the session variable is not being found because the file is posted to via an ajax request?

EDIT/ANSWER: I found out what was wrong. I was using a flash uploader, and sessions are lost when making an upload with flash. Oh what a night.

Thanks for all your help!

Answer 1

Is the page 'insert.php' has session started? It may be the reason.

Try to start it if the PHP setting is not set to auto start.

session_start();

I also find out print out the $_SESSION sometimes handy.

print_r($_SESSION);

From my experience, there is another possibility, which is the other file is called from different host/servername/IP number, which cause the session variables not found. Although this is quite remote possibility.

In your case, try to check it out just in case.

Answer 2

If you redirect not include insert.php you have use session_start();, because session not existing in that page, as far as I know php sessions working only in one page without extra configuration.

Answer 3

I found out what was wrong. I was using a flash uploader, and sessions are lost when making an upload with flash.