# File lib/sinatra/url_for.rb, line 34
    def api_url_for(url_fragment, mode=:path_only)
      matrix_params = ''
      if request.params['api']
        matrix_params += ";provider=%s" % request.params['api']['provider'] if request.params['api']['provider']
        matrix_params += ";driver=%s" % request.params['api']['driver'] if request.params['api']['driver']
      end
      url_fragment = "/#{url_fragment}" unless url_fragment =~ /^\// # There is no need to prefix URI with '/'
      url_for "#{DEFAULT_URI_PREFIX}#{matrix_params}#{url_fragment}", mode
    end