Function requestAmphtmlDocUrl

build-system/server/app.js:197–213

* Resolves an AMPHTML URL from a canonical URL. If AMPHTML is canonical, same * URL is returned. * @param {string} urlSuffix URL without protocol or google.com/amp/s/... * @param {string=} protocol 'https' or 'http'. 'https' retries using 'http'. * @return {!Promise }

(urlSuffix, protocol = 'https')

 * @return {!Promise<string>}
 */
async function requestAmphtmlDocUrl(urlSuffix, protocol = 'https') {
  const defaultUrl = `${protocol}://${urlSuffix}`;
  logWithoutTimestamp(`Fetching URL: ${defaultUrl}`);

  const response = await fetch(defaultUrl);
  if (!response.ok) {
    if (protocol == 'https') {
      return requestAmphtmlDocUrl(urlSuffix, 'http');
    }
    throw new Error(`Status: ${response.status}`);
  }

  const {window} = new jsdom.JSDOM(await response.text());
  const linkRelAmphtml = window.document.querySelector('link[rel=amphtml]');
  const amphtmlUrl = linkRelAmphtml && linkRelAmphtml.getAttribute('href');
  return amphtmlUrl || defaultUrl;
}

/*
 * Intercept Recaptcha frame for,