Not setting cache headers for images

[sophiajt]

Edit, @chriskrycho, 2018-11-20: Original title was 'Flicker of phrase "Rust Logo" on screen transfer'. Updated after investigation.

---

Which switching pages, we sometimes get the phrase "Rust Logo" where the top-left logo is.

Example:

[ashleygwilliams]

the phrase "Rust Logo"

that's the alt text showing while the image is being loaded. this is a performance issue.

[chriskrycho]

Did a tiny bit of digging on this and we're just not setting the cache headers for any images, so they're always being reloaded.

[coder543]

Right now, no assets at all from the origin are declaring a caching policy, as far as I can tell, so all content has to be reloaded every time. The static assets (images, css, etc.) are also not hashed, which makes caching even harder. Instead of skeleton.css, I would normally expect to see skeleton-6c1d4c04bb55a87b9cb81ffdbd683662.css or whatever, with an unlimited cache duration. If the asset is updated, the HTML references a different file that the browser hasn't seen before since the hash is now different, so it would immediately retrieve the new asset. The actual HTML pages would just be normal names like index.html, but they could still have a pretty reasonable cache policy of an hour or two. Good caching policies would make the website feel so much faster.

As I mentioned over on #372, I'm surprised that this isn't just a bunch of pre-built static content generated by hugo (or some Rust equivalent, if necessary) that's dumped into an S3 bucket and fronted by Cloudflare, CloudFront, Netlify, or something, which would make all of this easier.