PHP Session data not being saved

Question

I have one of those "I swear I didn't touch the server" situations. I honestly didn't touch any of the php scripts. The problem I am having is that php data is not being saved across different pages or page refreshes. I know a new session is being created correctly because I can set a session variable (e.g. $_SESSION['foo'] = "foo" and print it back out on the same page just fine. But when I try to use that same variable on another page it is not set! Is there any php functions or information I can use on my hosts server to see what is going on?

Here is an example script that does not work on my hosts' server as of right now:

<?php
session_start();
if(isset($_SESSION['views']))
    $_SESSION['views'] = $_SESSION['views']+ 1;
else
    $_SESSION['views'] = 1;

echo "views = ". $_SESSION['views'];
echo '<p><a href="page1.php">Refresh</a></p>';
?>

The 'views' variable never gets incremented after doing a page refresh. I'm thinking this is a problem on their side, but I wanted to make sure I'm not a complete idiot first.

Here is the phpinfo() for my hosts' server (PHP Version 4.4.7):

Answer 1

Check the value of "views" when before you increment it. If, for some bizarre reason, it's getting set to a string, then when you add 1 to it, it'll always return 1.

if (isset($_SESSION['views'])) {
    if (!is_numeric($_SESSION['views'])) {
        echo "CRAP!";
    }
    ++$_SESSION['views'];
} else {
    $_SESSION['views'] = 1;
}

Answer 2

I spent ages looking for the answer for a similar problem. It wasn't an issue with the code or the setup, as a very similar code worked perfectly in another .php on the same server. Turned out the problem was caused by a very large amount of data being saved into the session in this page. In one place we had a line like this:$_SESSION['full_list'] = $full_list where $full_list was an array of data loaded from the database; each row was an array of about 150 elements. When the code was initially written a couple of years ago, the DB only contained about 1000 rows, so the $full_list contained about 100 elements, each being an array of about 20 elements. With time, the 20 elements turned into 150 and 1000 rows turned into 17000, so the code was storing close to 64 meg of data into the session. Apparently, with this amount of data being stored, it refused to store anything else. Once we changed the code to deal with data locally without saving it into the session, everything worked perfectly.

Answer 3

Just wanted to add a little note that this can also occur if you accidentally miss the session_start() statement on your pages.

Answer 4

Check to see if the session save path is writable by the web server.

Make sure you have cookies turned on.. (I forget when I turn them off to test something)

Use firefox with the firebug extension to see if the cookie is being set and transmitted back.

And on a unrelated note, start looking at php5, because php 4.4.9 is the last of the php4 series.

Answer 5

A common issue often overlooked is also that there must be NO other code or extra spacing before the session_start() command.

I've had this issue before where I had a blank line before session_start() which caused it not to work properly.

Answer 6

Use phpinfo() and check the session.* settings.

Maybe the information is stored in cookies and your browser does not accept cookies, something like that.

Check that first and come back with the results.

You can also do a print_r($_SESSION); to have a dump of this variable and see the content....

Regarding your phpinfo(), is the session.save_path a valid one? Does your web server have write access to this directory?

Hope this helps.