vip-worker.js

class AttributeWriter {
  constructor(cf_object) {
    this.cf_object = cf_object;
  }

  async element(element) {
    const data = this.cf_object;

    // Is the visitor in the VIP list?
    const visitor_asn = data.asn
    const network_name = await VIP_API_ASN.get(visitor_asn)
    const is_vip = (network_name !== null)
    const message = 'vip: ' + (is_vip ? 'yes' : 'no ') + '; ' + data.asn.toString().padStart(7) + ' - ' + data.asOrganization

    // Log the result for debugging
    console.log(message);

    // Pass the result back as an HTML attribute so that
    // JS in the browser can access it.
    element.setAttribute('data-cf-vip', message)
  }
}


async function handleRequest(request) {
  response = await fetch(request);
  return new HTMLRewriter().on('body', new AttributeWriter(request.cf)).transform(response);
}


addEventListener('fetch', event => {
  event.respondWith(handleRequest(event.request));
});