77 lines
2.6 KiB
JavaScript
77 lines
2.6 KiB
JavaScript
// Calendarr Service Worker — minimal-cache strategy
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//
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// Strategy: network-first for everything. The cache is only used as a
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// last-resort fallback when offline (so the app shell still opens). This
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// means every online request hits the network and respects the
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// server's Cache-Control headers (≤ 2h for static assets, no-cache for
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// the entry HTML / version files). New releases take effect on the next
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// reload, no manual SW unregister required.
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const CACHE_VERSION = 'calendarr-v23';
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const OFFLINE_SHELL = ['/', '/index.html'];
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self.addEventListener('install', event => {
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event.waitUntil(
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caches.open(CACHE_VERSION).then(cache =>
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Promise.all(OFFLINE_SHELL.map(url =>
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cache.add(url).catch(err => console.warn('[SW] skip', url, err))
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))
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).then(() => self.skipWaiting())
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);
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});
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self.addEventListener('activate', event => {
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event.waitUntil(
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caches.keys().then(keys =>
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Promise.all(keys.filter(k => k !== CACHE_VERSION).map(k => caches.delete(k)))
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).then(() => self.clients.claim())
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);
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});
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self.addEventListener('fetch', event => {
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const req = event.request;
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if (req.method !== 'GET') return;
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const url = new URL(req.url);
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// API routes: always go to the network, no offline fallback (we'd just
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// be returning stale account/event data otherwise).
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if (url.pathname.startsWith('/api/')) {
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event.respondWith(
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fetch(req).catch(() =>
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new Response(JSON.stringify({ offline: true }), {
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status: 503,
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headers: { 'Content-Type': 'application/json' },
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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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// Everything else: network-first. The browser's HTTP cache (driven by
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// the server's Cache-Control headers) already throttles re-fetches —
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// the SW just makes sure offline still works for the entry HTML.
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event.respondWith(
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fetch(req).then(resp => {
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// Keep a fresh copy of navigation requests / index.html for offline
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const isNavigation = req.mode === 'navigate'
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|| url.pathname === '/'
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|| url.pathname === '/index.html';
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if (isNavigation && resp && resp.status === 200) {
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const clone = resp.clone();
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caches.open(CACHE_VERSION).then(c => c.put(req, clone)).catch(() => {});
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}
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return resp;
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}).catch(() => {
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// Offline fallback: only the HTML shell is served from cache, so the
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// app at least renders and can show its own offline UI.
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if (req.mode === 'navigate'
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|| url.pathname === '/'
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|| url.pathname === '/index.html') {
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return caches.match(req).then(c => c || caches.match('/index.html'));
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}
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return new Response('', { status: 503 });
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})
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);
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});
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