Block on TLS

async function handleRequest(request) {
  try {
    const tlsVersion = request.cf.tlsVersion;

    // Allow only TLS versions 1.2 and 1.3
    if (tlsVersion !== 'TLSv1.2' && tlsVersion !== 'TLSv1.3') {
      return new Response('Please use TLS version 1.2 or higher.', {
        status: 403,
      });
    }

    return fetch(request);
  } catch (err) {
    console.error('request.cf does not exist in the previewer, only in production');
    return new Response('Error in workers script' + err.message, {
      status: 500,
    });
  }
}

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