Cloudflare Worker audio streaming from Backblaze B2

worker.js

const cache = caches.default;

addEventListener("fetch", (event) => {
    try {
        const request = event.request
        return event.respondWith(handleRequest(event))
    } catch (e) {
        return event.respondWith(new Response("Error thrown " + e.message))
    }
});

async function handleRequest (event) {

    const request = event.request;
    const cacheUrl = new URL(request.url);

    // Construct the cache key from the origin URL and the request
    // The Range header will be included in the request
    const originUrl = 'https://f000.backblazeb2.com/file/bucket-name' + cacheUrl.pathname;
    const cacheKeyRequest = new Request(originUrl, request);

    // Return cached range bytes
    const cachedResponse = await cache.match(cacheKeyRequest);
    if (cachedResponse) return cachedResponse;

    // If the file is not cached fetch the file from origin
    const originResponse = await fetch(cacheKeyRequest);

    // Create a new response so we can strip B2 headers
    const response = new Response(originResponse.body);
    response.headers.append("Cache-Control", "s-maxage=500");
    response.headers.append("content-type", "audio/mpeg");

    // Save the full file to the cache once the response has been sent to the client
    event.waitUntil(cache.put(cacheKeyRequest, response.clone()));

    return response;
}