ef439a5d8e
The print-time files are pinned (poster-render.js and its classic copy, packet-strings.json, ne-places.json, india-states.json) and were fetched with cache: 'force-cache', which returns any cached copy, however old. After a re-pin, a reader who had printed before kept the previous copy: it failed its pin on every print and the print fell back without a word. Page 1 became the stored poster, a non-English packet would print in English, and India's state cards would be lost. sha384.js fetchPinned fetches force-cache first (fast, and offline once cached) and, when the copy is not served or fails its pin, once more with cache: 'reload', which skips and refreshes the HTTP cache; only that answer decides. posterSheets (the generator and the places table), packetStrings and indiaStates all fetch through it. The classic-script path refreshes the cache the same way and retries a refused tag once. check:pinned-fetch-fresh models the HTTP cache with stale copies: page 1 still draws, the packet keeps every language, India keeps its 36 states; a matching cached copy is used with one request; wrong bytes are refused. The previous loaders fail it. Self-test poisons: no fresh refetch, never the cache, a mismatch accepted, a loader fetching its pinned file directly.
31 lines
1.8 KiB
JavaScript
31 lines
1.8 KiB
JavaScript
// The Subresource-Integrity form of a text's SHA-384 ("sha384-<base64>"), via WebCrypto, so a file fetched at
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// print time can be compared with the pin baked into the bundle (poster-render.integrity.js) before it is used.
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// The same value pin-poster-render.mjs computes with node:crypto.
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export async function sha384(text) {
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const d = new Uint8Array(await crypto.subtle.digest('SHA-384', new TextEncoder().encode(text)))
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let bin = ''
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for (const b of d) bin += String.fromCharCode(b)
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return `sha384-${btoa(bin)}`
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}
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// ★ A PINNED FILE THAT FAILS ITS PIN IS FETCHED ONCE MORE, FRESH. The loaders fetch with cache: 'force-cache' (fast,
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// and it works offline once cached), which returns ANY cached copy, however old. After a re-pin, a reader who had
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// printed before kept the previous file: it failed its pin on every print, and the print fell back without a word
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// (the stored poster for page 1, English for the packet text) until the browser evicted it. So a copy that is not
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// served or does not match is fetched ONCE more with cache: 'reload', which skips the HTTP cache and refreshes it,
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// and only that answer decides. Resolves with the verified text; rejects with the last reason (err.integrity is
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// true when the bytes were wrong rather than missing).
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export async function fetchPinned(url, pin) {
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let last = null
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for (const cache of ['force-cache', 'reload']) {
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try {
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const res = await fetch(url, { cache })
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if (!res.ok) { last = new Error(`not served (${res.status})`); continue }
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const text = await res.text()
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const got = await sha384(text)
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if (got === pin) return text
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last = Object.assign(new Error(`failed its integrity check (expected ${pin}, got ${got})`), { integrity: true })
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} catch (e) { last = e }
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}
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throw last
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}
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