==== Configuration options
:session_id_cookie_only<Boolean>::
  If true, sessions may be passed only through cookies. If false, they may also
  be passed through the session_id_key query param. This might be necessary for
  flash uploaders, which do not pass cookies with file uploads. This can be
  used in conjunction with :query_string_whitelist.
:query_string_whitelist<Array[String]>::
  A list of "controller/action" URLs that should allow session IDs to be passed
  through the query string even if :session_id_cookie_only is set to true. We
  recommend using session.regenerate after any controller making use of this
  in case someone is trying a session fixation attack.