使用PHP / Nginx将cookie域从无域迁移到.mydomain.com

Question

I have a web site wrote with PHP and running on Nginx HTTP server. I have a cookie called "locale" which represents the user locale. For 6 months, I am sending the cookie like this:

setCookie("locale", "fr", time() + 36000, "/");

As a cookie less domain, I understand it's only available on my single domain "www.mydomain.com".

But now, I want to create 2 news sub domains:

1. m.mydomain.com (the mobile part)
2. secure.mydomain.com (a secure version)

I see "locale" cookie set on www is not accessible by m or secure. So now I am sending the cookie like this:

setCookie("locale", "fr", time() + 36000, "/", ".mydomain.com");

Yeah my cookie is available everywhere now! But as I have some users who had already browsed my web site, they have the domain less cookie + the new one, their browser send me both cookies but PHP gives me the former one. As a result nobody can change the locale any more.

Question is: how can I migrate from this domain less cookie to a domain specified cookie? Without change the cookie name.

Answer 1

The first cookie you set without the domain defaulted to www.mydomain.com and because that's more specific than '.mydomain.com' it's choosing the original cookie. Read the accepted answer here.

How to get the domain of a specific cookie?

Answer 2

As conclusion, I will put this in my index.php file during 1 week:

setCookie('locale', null, time() - 5000, '/');

In order to delete the domain-less cookie. I have tested on all major browser, and I don't see any conflict with:

setCookie('locale', 'fr', time() + 36000, '/', '.mydomain.com');