# File lib/action_controller/session/cookie_store.rb, line 52
  def initialize(session, options = {})
    # The session_key option is required.
    if options['session_key'].blank?
      raise ArgumentError, 'A session_key is required to write a cookie containing the session data. Use config.action_controller.session = { :session_key => "_myapp_session", :secret => "some secret phrase" } in config/environment.rb'
    end

    # The secret option is required.
    ensure_secret_secure(options['secret'])

    # Keep the session and its secret on hand so we can read and write cookies.
    @session, @secret = session, options['secret']

    # Message digest defaults to SHA1.
    @digest = options['digest'] || 'SHA1'

    # Default cookie options derived from session settings.
    @cookie_options = {
      'name'    => options['session_key'],
      'path'    => options['session_path'],
      'domain'  => options['session_domain'],
      'expires' => options['session_expires'],
      'secure'  => options['session_secure'],
      'http_only' => options['session_http_only']
    }

    # Set no_hidden and no_cookies since the session id is unused and we
    # set our own data cookie.
    options['no_hidden'] = true
    options['no_cookies'] = true
  end