franklin-html.worker.js

/*
 * A Cloudflare Worker to accept `.html` requests
 * and forward to Franklin.
 *
 * This is helpful for any site that wishes to continue
 * using `.html` for legacy reasons.
 *
 */
const removeHtml = (path) => {
  const pathSplit = path.split('/');

  const page = pathSplit.pop();
  const pageSplit = page.split('.');
  const pageExt = pageSplit.pop();
  if (pageExt !== 'html') return path;

  const pageName = pageSplit.pop();
  if (pageName === 'plain' && pageSplit.length > 0) return path;
  
  const newPath = pathSplit.join('/');
  if (pageName === 'index') return newPath;
  return `${newPath}/${pageName}`;
};

const handleRequest = async (request, env, ctx) => {
  const url = new URL(request.url);
  url.hostname = env.ORIGIN_HOSTNAME;
  url.pathname = removeHtml(url.pathname);
  const href = `${url.origin}${url.pathname}${url.search}${url.hash}`;
  const req = new Request(href, request);
  req.headers.set('x-forwarded-host', req.headers.get('host'));
  req.headers.set('x-byo-cdn-type', 'cloudflare');
  req.headers.set('x-push-invalidation', 'enabled');
  let resp = await fetch(req, {
    cf: {
      cacheEverything: true,
    },
  });
  resp = new Response(resp.body, resp);
  resp.headers.delete('age');
  resp.headers.delete('x-robots-tag');
  return resp;
};

export default {
  fetch: handleRequest,
};

in https://gist.github.com/auniverseaway/c47ad73dbbf493e3e3da9b8dd86443cb#file-franklin-html-worker-js-L27-L30 why do you recompose the href manually and not just use the URL object? eg:

 url.hostname = env.ORIGIN_HOSTNAME;
 url.pathname = removeHtml(url.pathname);
 const req = new Request(url.href, request);

In https://gist.github.com/auniverseaway/c47ad73dbbf493e3e3da9b8dd86443cb#file-franklin-html-worker-js-L21 you should append a / to newPath (or just set pageName to ''.