PHP Session shared with subdomain

Question

I have read many forums (including this one) about passing session variables between subdomains, and I can't get this to work. Can someone explain what I am missing?

Step 1 In the php.ini file: session.cookie_domain = ".mydomain.com" Verified with phpinfo() that I am using the right php.ini file

Step 2 In page at www.mydomain.com set a session variable $_SESSION['a'] , verify that it appears by calling it on the next page (it does). Clink link to sub.mydomain.com

Step 3 Page at sub.mydomain.com checks if session variable is set using:

$a = $_SESSION['a']; if(!isset($_SESSION['a'])){ echo "Error: Session Variable not available"; }

Unfortunately I am getting my error message. What am I missing? Thanks in advance for help.

Answer 1

debugging.
is the thing you're missing.

first of all you have to watch HTTP headers to see what is going on and what cookies actually being set. You can use LiveHTTPHeaders Firefox addon or something. With such info you can find the problem. Without it noone can answer tour question "my sessions don't work"

It can prove your statement of proper domain setting in the session settings. Or disprove it.
It can reveal some other misconfiguring.
It may show you cookie being sent back by the browser - so you can be sure that is server side problem

To see the actual result of your code (instead of guessing based on the indirect consequences) always helps.

Answer 2

So, I went a different direction and used this entry which worked...

session_set_cookie_params(0, '/', '.mydomain.com'); session_start();