Will Anderson
78 lines
2.6 KiB
JavaScript
78 lines
2.6 KiB
JavaScript
// Service worker for the Neuron PWA powered by engram-lang.
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//
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// Caching strategy:
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// /pkg/ — WASM runtime files, cache-first (content-addressed, change on version bump)
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// *.elc — compiled bytecode, stale-while-revalidate (instant load, background update)
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//
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// The WASM runtime is fetched once and cached indefinitely.
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// Engram programs (.elc) are served from cache immediately, then refreshed in
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// the background so the next load gets the newest version — no user action needed.
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const CACHE_NAME = 'engram-v1';
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const WASM_CACHE = 'engram-wasm-v1';
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// Files to pre-cache during service worker installation.
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const PRECACHE = [
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'/pkg/el_wasm_bg.wasm',
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'/pkg/el_wasm.js',
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];
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self.addEventListener('install', event => {
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event.waitUntil(
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caches.open(WASM_CACHE).then(cache => cache.addAll(PRECACHE))
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);
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// Take control immediately — don't wait for existing tabs to close.
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self.skipWaiting();
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});
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self.addEventListener('fetch', event => {
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const url = new URL(event.request.url);
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// WASM runtime files: cache-first.
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// These are large and rarely change; the version bump forces a new URL.
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if (url.pathname.startsWith('/pkg/')) {
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event.respondWith(
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caches.match(event.request).then(cached =>
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cached || fetch(event.request).then(response => {
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caches.open(WASM_CACHE).then(cache =>
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cache.put(event.request, response.clone())
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);
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return response;
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})
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)
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);
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return;
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}
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// Compiled bytecode (.elc): stale-while-revalidate.
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// Respond immediately from cache, update in background.
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if (url.pathname.endsWith('.elc')) {
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event.respondWith(
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caches.open(CACHE_NAME).then(async cache => {
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const cached = await cache.match(event.request);
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const fetchPromise = fetch(event.request).then(response => {
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cache.put(event.request, response.clone());
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return response;
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});
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return cached || fetchPromise;
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})
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);
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return;
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}
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});
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self.addEventListener('activate', event => {
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// Purge old cache versions to reclaim storage.
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event.waitUntil(
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caches.keys().then(keys =>
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Promise.all(
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keys
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.filter(k => k !== CACHE_NAME && k !== WASM_CACHE)
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.map(k => caches.delete(k))
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)
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)
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);
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// Claim all clients immediately.
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self.clients.claim();
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});
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