# File lib/omniauth/strategies/saml.rb, line 32
      def request_phase
        options[:assertion_consumer_service_url] ||= callback_url
        runtime_request_parameters = options.delete(:idp_sso_target_url_runtime_params)

        additional_params = {}

        if runtime_request_parameters
          runtime_request_parameters.each_pair do |request_param_key, mapped_param_key|
            additional_params[mapped_param_key] = request.params[request_param_key.to_s] if request.params.has_key?(request_param_key.to_s)
          end
        end

        authn_request = OneLogin::RubySaml::Authrequest.new
        settings = OneLogin::RubySaml::Settings.new(options)

        redirect(authn_request.create(settings, additional_params))
      end