Rewrite URL with CloudFlare for Domino

Years ago I created few solutions for Domino using DSAPI:

1. remove last slash in URL served by Domino.
2. rewrite URL.
3. better control over 404/500 error pages.

It was quite complicated solution (DSAPI is not easy topic).

Today another client asked similar features (remove last slash and rewrite url).

I started to recall how DSAPI works but then I reminded myself that the client stick with CloudFlare in front of their Domino servers.

Cloudflare has 'page rules' which allow to solve issue with last trailing slash. Just matter of configuration.

And about rewriting URL it's actually possible to achieve with workers! You can see below how to rewrite URL.

In example below I changed url like
domain.com/section/page?param1=aaa&param2=bbb
=>
domain.com/router?openagent&req=section/page&param1=aaa&param2=bbb

addEventListener('fetch', event => {
  const url = new URL(event.request.url);
  const pathname = url.pathname.substr(1);
  if (pathname.startsWith("design") || pathname.startsWith("files") || pathname.startsWith("api")) {
    return;
  }
  event.respondWith(handleRequest(event.request));
})

/**
 * Rewrite URL and makes query param available
 * @param {Request} request
 */
async function handleRequest(request) {
  let url = new URL(request.url);
  let pathname = url.pathname.substr(1);
  url.pathname = "?openagent&req="+pathname;
  var query = url.search;
  if (query!="") {
    url.pathname += "&" + query.substr(1);
  }

  const newRequest = new Request(url, new Request(request));
  return await fetch(newRequest)
}