CloudFlare worker to rewrite Host header for S3

s3hostfix.js

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

const lookup = {
  "mybucket.example.com": "https://my-s3-bucket.s3.us-east-1.amazonaws.com",
};

async function handleRequest(origRequest) {
    const origUrl = new URL(origRequest.url);
    const newOrigin = lookup[origUrl.hostname];
    let request = origRequest;
    if (newOrigin) {
      const newUrl = origRequest.url.replace(origUrl.origin, newOrigin);
      request = new Request(newUrl, {
        body: origRequest.body,
        headers: origRequest.headers,
        method: origRequest.method,
        redirect: origRequest.redirect
      });
    }
    const response = await fetch(request);
    // console.log({ response });
    return response;
}