Cloudflare Developers•3w ago

Static Assets HTML 304 local but 200 only when deployed

I'm trying to experiment with the advantages of building out a static site through static assets and pre-compiled HTML. Locally, when I serve up a page, I see an initial 200 response with a 304 + ETAGS, as expected, on reload. However, when I deploy this bare-bones worker and load it up, I only see 200 responses and it never sets ETAGS to take advantage of 304 responses. Also, when developing locally, if you enable assets in wrangler, it seems that no console logs get executed... at all. There seems to be some kind of aggressive caching happening locally. In fact, if I delete the entire fetch handler and restart the worker, it loads from cache even on a hard reload. Is this normal?

3 Replies

fry69•3w ago

See -> https://developers.cloudflare.com/cache/concepts/default-cache-behavior/

The Cloudflare CDN does not cache HTML or JSON by default.

Cloudflare Docs

Default cache behavior | Cloudflare Cache (CDN) docs

Cloudflare respects the origin web server’s cache headers in the following order unless an Edge Cache TTL cache rule overrides the headers. Refer to the Edge TTL section for details on default TTL behavior.

fry69•3w ago

Static assets from Workers bypass the cache by default? News to me. I was under the impression that static assets get treated as sourced by origin? E.g. when I do a trace I see the worker is of type "origin" and the cache rule matches. Counter indicative is that I do not see a high enough number of cached responses currently. This is a bit confusing. I do see the necessary etag and other headers in the response, though, with the cache rule for static assets. So I think the reason that I do not see many cache hits is just because there not many returning requests currently (fresh domain without real traffic). I am pretty certain that static assets are the origin and the default cache behavior and cache rules apply? But thank you help me understanding this, although your remarks were initially not helpful. This again not very helpful and confusing remark does not reflect by what I read from the docs. Okay, this starts to make sense. Thank you.

Murder ChickenOP•3w ago

Ok, I think I'm getting confused. So, if we have a worker leveraging static assets to deliver pre-compiled HTML (generated during the build process and pushed to the /public directory) to the browser, what's the best practice to ensure that it's taking advantage of proper best-practices for browser / server caching? What's confusing me is that when using npx wrangler dev to view the site locally, I'm seeing what I would expect... which is that on the initial load, a 200 response with an ETAG header and then upon second load, a 304 response with both ETAG and If-None-Match headers. However, when I deploy this simple script (which is deployed to a testing subdomain of my primary domain, i.e., sandbox.domain.com), I only see 200 responses for the HTML page." At first, I thought that this might have something to do with setting a Cache rule to enforce strong ETAGs. So, I created a cache rule for all incoming requests to respect strong ETAGs. Now the ETAGs show up and I see 304 responses but without bronti (or any) compression. So, I'm starting to get a bit lost about best practices here and any explanations would be appreciated. --- BONUS QUESTION As a follow up question, I'm seeing really strange behavior with local Workers using static assets. Take, for example, this very simple fetch handler...

export default {
  async fetch(request, env, ctx) {
    // console.log('TEST LOG');
    const url = new URL(request.url);
    let path = url.pathname;
    try {
      const response = await env.ASSETS.fetch(path);
      if (response.status === 404) {
        return new Response('Not Found', { status: 404 });
      }
      return response;
    } catch (error) {
      return new Response('Internal Error', { status: 500 });
    }
  },
};

export default {
  async fetch(request, env, ctx) {
    // console.log('TEST LOG');
    const url = new URL(request.url);
    let path = url.pathname;
    try {
      const response = await env.ASSETS.fetch(path);
      if (response.status === 404) {
        return new Response('Not Found', { status: 404 });
      }
      return response;
    } catch (error) {
      return new Response('Internal Error', { status: 500 });
    }
  },
};

So, ASSETS maps to the /public directory which has two HTML files. These will render properly. If I uncomment that console.log, it will not show up when I serve up the site locally. Furthermore, if I literally delete the entire contents of the fetch handler... reload the worker... I can still hit the site. What kind of caching is going on here that allows that?

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Static Assets HTML 304 local but 200 only when deployed