php - Cross domain session sharing does not work until site visited in browser -

i have script setup allows me communicate across 2 domains via javascript - foo.example.com bar.example.com.

when cross-domain request hits server make sure set access control headers follows (in kohana):

$this->response->headers('access-control-allow-origin', 'foo.example.com')); $this->response->headers('access-control-allow-credentials', 'true'); $this->response->headers('access-control-allow-methods', 'post, get, options'); 

i make sure kohana knows want share cookies across sub-domains:

cookie::$expiration = 60 * 60 * 24 * 14; cookie::$salt = 'salt-string-which-is-the-same-on-both-domains'; cookie::$httponly = true; cookie::$domain = '.example.com'; 

i've set javascript use single domain (as have iframes going cross-domain well):

document.domain = "example.com"; 

i use xhrfields property when making $.ajax() requests:

xhrfields: {     withcredentials: true } 

the problem

the problem have when used altogether perform cross-domain ajax request session on second instance bar.example.com doesn't read cookie(s) sent it. if dump session it's blank session shell.

however if hit second instance directly , try ajax scripts works expected. leads me believe issue reading cookie(s).

any ideas?

i believe have found causing issue. because both domains served separate instance have unique php environments running. code using native php session - when cookie sent second server gets id no data allocated.

it's visiting site manually triggers allocation of data automatically runs through authentication , authorisation procedure. going switch using database session in kohana. both instances point same db should resolve issue.

i'll post here confirm.