perf(cache): short TTL for gallery image listings#513
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The public gallery image-list caches (`gallery` tag) are the only cached reads whose freshness depends on a background source: the preprocess ticker flips `variants_ready` outside request scope and therefore cannot call `revalidateTag` (Next throws "Invariant: static generation store missing" with no work store). Those updates were only picked up when the 1h safety-net TTL expired, so a freshly-processed image could keep showing its placeholder for up to an hour after its variants were ready. Give the four `gallery`-tagged wrappers their own 60s TTL while leaving albums/config at 1h. Albums and config only change via admin writes that bust their tags synchronously in request scope, so they keep the long safety-net TTL. Admin writes still invalidate the gallery tag instantly via `revalidateGalleryCache`; the short TTL only bounds the background-ticker gap (now <=60s) and still absorbs the bulk of repeat reads, so page-1 first paint stays a cache hit for most requests.
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Background
The public gallery image-list caches (the
gallerytag inserver/lib/cache.ts) are the only cached reads whose freshness depends on a background source. The preprocess ticker flipsvariants_readyoutside request scope, so it cannot callrevalidateTag— Next throwsInvariant: static generation store missingwhen there is no work store. As a result, that update was only picked up when the 1h safety-net TTL expired, so a freshly-processed image could keep showing its placeholder for up to an hour after its variants were actually ready.Change
Give the four
gallery-tagged wrappers their own 60s TTL, while leaving thealbumsandconfigcaches at 1h.albums/configonly change via admin writes, which bust their tags synchronously in request scope — so a long safety-net TTL remains fine for them.gallerytag instantly viarevalidateGalleryCache(image create / update / delete / show-hide / sort). The short TTL only bounds the background-ticker gap, now ≤60s instead of ≤1h.Why option ① (short TTL) over the alternatives
getImagesData(1, album)during page render, so the image-list cache helps first paint — dropping it adds a DB query there.Short TTL is one line per wrapper, keeps the page-1 first-paint cache hit, and bounds staleness to ≤60s.
Scope / risk
albums/config, no change to the auth/render model.