Can not get session in cakePHP.

Hi all,

I have problem with session in cakephp.I have one file chat.php that is in webroot folder but when I run that file with ajax I could not find session which is created from chat.ctp file.
so anyone has idea how to get session in third party file in cakePHP.

can I write session any .ctp file ?

Thanks.please help me.