sw.js

/**
 * THE CIPHER MUSEUM — Service Worker
 * Offline support for classrooms and flaky connections.
 *
 * Strategy:
 *   - HTML navigations: network-first, falling back to cache (content stays fresh
 *     online; cached pages may be available offline while their assets remain cached).
 *   - Static assets (css/js/images/json): cache-first with background refresh.
 *   - Requests under /public/, including corpus samples and reports, bypass this cache.
 *
 * VERSION is stamped automatically by `npm run build:js` from a hash of every
 * asset served cache-first — the minified bundles, the non-HTML entries of
 * CORE below, and the self-contained offline fallback page (scripts/sw-version.js).
 * tests/test-sw-version.js fails the suite if it drifts. Old caches are purged
 * on activate, so adding an asset to CORE also re-stamps VERSION.
 */
'use strict';

const VERSION = 'cipher-museum-868b5b92';

const CORE = [
  '/',
  '/index.html',
  '/offline.html',
  '/ciphers/myszkowski.html',
  '/ciphers/turning-grille.html',
  '/ciphers/hagelin-c36.html',
  '/ciphers/nema.html',
  '/ciphers/rs44.html',
  '/ciphers/double-playfair.html',
  '/ciphers/amsco.html',
  '/css/manual-cipher-demos.css',
  '/js/manual-cipher-demos.js',
  '/css/multiple-anagramming.css',
  '/js/multiple-anagramming.js',
  '/css/pad-experiments.css',
  '/js/pad-experiments.js',
  '/css/detective-workspaces.css',
  '/js/detective/workspaces.js',
  '/js/detective/playback.js',
  '/js/detective/lang-model.js',
  '/lab/evidence-workbench.html',
  '/lab/decipherment-cases.html',
  '/lab/modern-attack-evidence.html',
  '/ciphers/ua-8295.html',
  '/ciphers/sodark.html',
  '/ciphers/nfc-deployment.html',
  '/css/research-workbench.css',
  '/js/research-model.js',
  '/js/research-worker.js',
  '/js/research-language-model.js',
  '/data/research/v1/language-model.json',
  '/js/research-ui.js',
  '/js/research-cases.js',
  '/data/research/v1/z340-section-1.json',
  '/js/ciphers/all-engines.min.js',
  '/css/museum.css',
  '/css/historical-demos.css',
  '/js/historical-ciphers.js',
  '/js/historical-demos.js',
  '/js/nav.js',
  '/js/footer.js',
  '/js/breadcrumbs.js',
  '/js/ui-delegates.js',
  '/js/trust-labels.js',
  '/js/search.js',
  '/js/search-index.json',
  '/js/artifact-cards.js',
  '/js/artifact-cards-data.min.js',
  '/js/demo-loader.min.js',
  '/js/lightbox.js',
  '/fonts/cinzel-400-latin-ext.woff2',
  '/fonts/cinzel-400-latin.woff2',
  '/fonts/cinzel-600-latin-ext.woff2',
  '/fonts/cinzel-600-latin.woff2',
  '/fonts/cinzel-700-latin-ext.woff2',
  '/fonts/cinzel-700-latin.woff2',
  '/fonts/cormorant-garamond-italic-300-latin-ext.woff2',
  '/fonts/cormorant-garamond-italic-300-latin.woff2',
  '/fonts/cormorant-garamond-italic-400-latin-ext.woff2',
  '/fonts/cormorant-garamond-italic-400-latin.woff2',
  '/fonts/cormorant-garamond-italic-600-latin-ext.woff2',
  '/fonts/cormorant-garamond-italic-600-latin.woff2',
  '/fonts/cormorant-garamond-300-latin-ext.woff2',
  '/fonts/cormorant-garamond-300-latin.woff2',
  '/fonts/cormorant-garamond-400-latin-ext.woff2',
  '/fonts/cormorant-garamond-400-latin.woff2',
  '/fonts/cormorant-garamond-600-latin-ext.woff2',
  '/fonts/cormorant-garamond-600-latin.woff2',
  '/fonts/cormorant-garamond-700-latin-ext.woff2',
  '/fonts/cormorant-garamond-700-latin.woff2',
  '/fonts/jetbrains-mono-300-latin-ext.woff2',
  '/fonts/jetbrains-mono-300-latin.woff2',
  '/fonts/jetbrains-mono-400-latin-ext.woff2',
  '/fonts/jetbrains-mono-400-latin.woff2',
  '/fonts/jetbrains-mono-500-latin-ext.woff2',
  '/fonts/jetbrains-mono-500-latin.woff2',
  '/fonts/jetbrains-mono-700-latin-ext.woff2',
  '/fonts/jetbrains-mono-700-latin.woff2',
  '/hall-of-foundations/index.html',
  '/hall-of-foundations/foundations.css',
  '/images/icons.svg',
  '/favicon.svg',
  '/manifest.webmanifest',
  '/images/icons/icon-192.png',
  '/images/icons/icon-512.png'
];

self.addEventListener('install', (event) => {
  event.waitUntil(
    caches.open(VERSION).then((cache) => cache.addAll(CORE)).then(() => self.skipWaiting())
  );
});

self.addEventListener('activate', (event) => {
  event.waitUntil(
    caches.keys()
      .then((keys) => Promise.all(keys.filter((k) => k !== VERSION).map((k) => caches.delete(k))))
      .then(() => self.clients.claim())
  );
});

self.addEventListener('fetch', (event) => {
  const req = event.request;
  if (req.method !== 'GET') return;
  const url = new URL(req.url);
  if (url.origin !== self.location.origin) return;
  // Bypass all /public/ requests, including corpus downloads, samples and reports.
  if (url.pathname.startsWith('/public/')) return;

  if (req.mode === 'navigate') {
    // Network-first for pages. An unvisited exhibit must display an explicit
    // offline notice, not the homepage at an exhibit URL with broken relative
    // assets (or misleading homepage content).
    event.respondWith(
      fetch(req)
        .then((res) => {
          const copy = res.clone();
          caches.open(VERSION).then((cache) => cache.put(req, copy));
          return res;
        })
        .catch(() => caches.match(req).then((hit) => hit || caches.match('/offline.html')))
    );
    return;
  }

  // Cache-first with background refresh for static assets.
  event.respondWith(
    caches.match(req).then((hit) => {
      const refresh = fetch(req)
        .then((res) => {
          if (res && res.ok) {
            const copy = res.clone();
            caches.open(VERSION).then((cache) => cache.put(req, copy));
          }
          return res;
        })
        .catch(() => hit);
      return hit || refresh;
    })
  );
});