# Cloudflare Workers

Converted <https://socialrecommendator.com> to a statically hosted, serverless cloud function invoking, single page app, from the single page php it was for 10 years. Mixing two cloud platforms, Firebase for the static hosting, and [Cloudflare Workers](https://workers.cloudflare.com/) for the cloud function (in stead of a Firebase Function). Still using old-school jQuery though.

Yes I could use a Firebase Function, but I wanted to use Cloudflare Workers. Firebase hosting is free, but Cloudflare hosting isn't. And I wanted to a try cross platform integration.

[Cloudflare Workers](https://workers.cloudflare.com/) is pretty straightforward to setup and call (with the regular CORS caveats). It's surprisingly simple to figure out and get working. There aren't three dozen of options to pick from. I was genuinely surprised that I got it to work from the first time. There's a [Playground](https://www.cloudflareworkers.com/) to play around with Workers.

Getting CORS to work (for my own domains), in the handleRequest(request) Cloudflare function:

```
<pre class="wp-block-preformatted">// array of my hostnames
const MY_HOSTNAMES = ['socialrecommendator.com',  'socialrecommendator-au.web.app', 'socialrecommendator-au.firebaseapp.com']; // custom domain + all Firebase domains
let url = new URL(request.url); 
let referer = request.headers.get('Origin');// origin should be one of my hosts
let refererHost = referer ? new URL(referer).hostname : new URL(request.url) ; // this in case if no referer, when I try this on the Cloudflare console
// only set CORS header for my hosts, so that request would fail for other hosts
if (MY_HOSTNAMES.includes(refererHost)) {
    response.headers.set('Access-Control-Allow-Origin', url.protocol + '//' + refererHost); // this should match the Origin header passed in to succeed
    response.headers.set('Access-Control-Allow-Credentials', false);
  }
```