Use the strategy as a middleware in your application:
require 'omniauth/openid'
require 'openid/store/filesystem'
use OmniAuth::Strategies::OpenID, OpenID::Store::Filesystem.new('/tmp')
Then simply direct users to '/auth/open_id' to prompt them for their OpenID identifier. You may also pre-set the identifier by passing an <tt>identifier</tt> parameter to the URL (Example: <tt>/auth/open_id?identifier=google.com</tt>).
== OmniAuth Builder
If OpenID is one of several authentication strategies, use the OmniAuth Builder: