mirror of
https://github.com/hanzoai/next.js.git
synced 2026-09-24 17:00:51 +00:00
Andrew ClarkandGitHub
3de2d1a213
Removes the "allow-runtime" prefetch config, and turns its behavior on implicitly wherever Partial Prefetching is enabled. The original motivation for "allow-runtime" was to give apps more control over server costs triggered by prefetches. Until a route explicitly opts in, prefetches would only be served from the CDN, not from the server. The problem, though, was it was very confusing to know when to add or remove this configuration. The incentive for many apps was to add it everywhere, with no clear signal for when to remove it. Our updated thinking is that Partial Prefetching itself already provides sufficient protection against runaway prefetching costs: per-link prefetches only happen on Link components that explicitly opt in with the prefetch prop. The optimizations landed earlier in this stack also make allow-runtime less necessary: on pages where all the content is statically renderable, prefetches are served from the static cache and no runtime request is ever issued; only a page that accesses non-static data is prefetched at runtime. The upshot of this decision is that runtime versus static becomes an internal optimization; the same content gets prefetched regardless of whether or how Next.js is able to optimize it.
37 lines
1.2 KiB
TypeScript
37 lines
1.2 KiB
TypeScript
import { Suspense } from 'react'
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import { setTimeout } from 'timers/promises'
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import { cacheLife } from 'next/cache'
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// A public `'use cache'` routed through the custom (slow) handler, with an
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// explicit short `expire`. In dev the built-in front handler applies a minimum
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// retention, so a cache hit still resolves from the front in a microtask
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// instead of paying the backing's latency on every read.
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async function getCachedValue() {
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'use cache'
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// `expire: 0` gives a short, dynamic (client-only) cache life, excluded from
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// static prerenders. Reusing it across client navigations would require
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// opting the route into Partial Prefetching (`prefetch = 'partial'`) so
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// Cached Navigations embeds it into the client router cache; this fixture
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// doesn't, since the test only exercises the dev front handler serving it
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// warm on reloads.
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cacheLife({ expire: 0 })
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await setTimeout(1000)
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return new Date().toISOString()
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}
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async function CachedValue() {
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const value = await getCachedValue()
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return <p id="value">{value}</p>
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}
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export default function Page() {
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return (
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<main>
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<Suspense fallback={<p id="loading">Loading...</p>}>
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<CachedValue />
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</Suspense>
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</main>
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)
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}
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