# File lib/googleauth/web_user_authorizer.rb, line 277
        def self.call env
          request = Rack::Request.new env
          return_url = WebUserAuthorizer.handle_auth_callback_deferred request
          if return_url
            [REDIR_STATUS, { LOCATION_HEADER => return_url }, []]
          else
            [ERROR_STATUS, {}, ["No return URL is present in the request."]]
          end
        end