Share session (cookies) between subdomains in Rails?

Question

I have an app setup where each user belongs to a company, and that company has a subdomain (I am using basecamp style subdomains). The problem that I am facing is that rails is creating multiple cookies (one for lvh.me and another for subdomain.lvh.me) which is causing quite a few breaks in my application(such as flash messages being persistent though out all requests once signed in).

I have this in my /cofig/initilizers/session_store.rb file:

AppName::Application.config.session_store :cookie_store, key: '_application_devise_session', domain: :all

The domain: :all seems to be the standard answer I found on Google, but that doesn't seem to be working for me. Any help is appreciated!

Answer 1

As it turns outs 'domain: all' creates a cookie for all the different subdomains that are visited during that session (and it ensures that they are passed around between request). If no domain argument is passed, it means that a new cookie is created for every different domain that is visited in the same session and the old one gets discarded. What I needed was a single cookie that is persistent throughout the session, even when the domain changes. Hence, passing domain: "lvh.me" solved the problem in development. This creates a single cookie that stays there between different subdomains.

For anyone needing further explanation, this is a great link: http://excid3.com/blog/sharing-a-devise-user-session-across-subdomains-with-rails-3/