Más legible pero con duplicación

middleware.rb

  def call(env)
    set_user_language_variable(env)
    set_include_language_banner_variable(env)
    call_haml_serve(env) do |response, preferred_locale|
      set_preferred_locale_cookie(response, preferred_locale) if AVAILABLE_LOCALES.include?(preferred_locale)
    end
  end

  def set_user_language_variable(env)
    if has_language_cookie?(env)
      env[:locale] = user_language_from_cookie(env)
    else
      browser_languages = BrowserLanguages.new(env['HTTP_ACCEPT_LANGUAGE'], AVAILABLE_LOCALES)
      env[:locale] = browser_languages.preferred_language
    end
  end

  def set_include_language_banner_variable(env)
    if has_language_cookie?(env)
      env[:include_language_banner] = false
    else
      browser_languages = BrowserLanguages.new(env['HTTP_ACCEPT_LANGUAGE'], AVAILABLE_LOCALES)
      env[:include_language_banner] = browser_languages.accepts_available_languages?
    end
  end