Martin Bauer 3fea56d4e1 Stop cover art going stale in two caches at once ...

Shrinking the covers changed nothing on the device, twice over, because two layers were
independently serving the old bytes and each had the same wrong premise written into its
comment: that a cover is "content-addressed by album id". The id addresses which album
the art belongs to. The bytes behind the URL change whenever the art is reprocessed.

The backend sent `public, max-age=604800`, so every browser that had loaded the page in
the previous week kept decoding the 3000px original out of its own disk cache without
asking. It now sends `no-cache`, which does not mean "do not store" but "revalidate
before reusing" - the file stays cached and the usual answer is a 304.

The service worker cached covers cache-first on a URL that never changes, which means a
client could serve a stale cover for ever; bumping the cache name fixed today's covers
and would have had to be done again for the next batch. It now does
stale-while-revalidate: the cached copy is returned immediately, so a grid of album art
still never waits on the network, and a fresh copy is fetched behind the page for next
time. Neither layer needs a version bump when art is reprocessed again.

The revalidation is off the paint path entirely, which is what makes `no-cache`
affordable here: the service worker answers first, the network call happens behind it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

2026-09-20 16:43:56 +02:00

3.9 KiB

Raw Blame History

View Raw