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I'm working on a site with multiple subdomains, some of which should get their own session.
I think I've got it worked out, but have noticed something about cookie handling that I don't understand. I don't see anything in the docs that explains it, so thought I would see if anyone here has some light to shed on the question.
If I just do:
session_start(); I end up with a session cookie like this:
subdomain.example.net
However, if I make any attempt to set the cookie domain myself, either like
ini_set('session.cookie_domain', 'subdomain.example.net'); or like
session_set_cookie_params( 0, "/", "subdomain.example.net", false, false); I end up with a cookie for .subdomain.example.net (note the opening dot), which I believe means "match all subdomains (or in this case sub-subdomains).
This seems to happen with all my cookies actually, not just session. If I set the cookie domain myself, it automatically has the dot prepended, meaning this domain and all subs of it. If I don't set the domain, then it gets it right by using only the current domain.
Any idea what causes this, and what I can do to control that prepending dot?
Thanks!
460
That is, if the domain name in your cookie's domain parameter doesn't start with a period, then it will not let subdomains read that cookie. If it does start with the period, then all subdomains will have full access to that cookie's value. Can only be read by example.com.
Conclusion: if a resource sets a cookie and the base domain on the resource is the same as the base domain on the web site, but the subdomain is different, popular browsers do not treat it as a third-party cookie.
To share a cookie between domains, you will need two domains, for example myserver.com and slave.com . One of the domains will issue the cookies and the other domain will ask the first domain what cookie should be issued to the client.
With PHP, you can both create and retrieve cookie values. The name of the cookie is automatically assigned to a variable of the same name. For example, if a cookie was sent with the name "user", a variable is automatically created called $user, containing the cookie value.
PHP's cookie functions automatically prefix the $domain with a dot. If you don't want this behavior you could use the header function. For example:
header("Set-Cookie: cookiename=cookievalue; expires=Tue, 06-Jan-2009 23:39:49 GMT; path=/; domain=subdomain.example.net"); If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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