Rails session makes values available from page to page by storing it in a cookie which expires when the browser closes, e.g
session[:foo] = "bar"Name _session_name
Value a_base_64_value
Host localhost
Path /Rails 3 session data is base64 encoded value, while for Rails 4 it is an encrypted value.
A cookie can be set to expire in the future so it still exists even if the browser is closed.
cookies[:foo] = { value: "bar", expires: 3.years.from_now.utc }Setting a cookie to expire far in the future became common enough that Rails added a special permanent method to implement it, e.g.
cookies.permanent[:foo] = "bar"