WS-1837: Service worker changes to render offline page

public/sw.js

@@ -3,19 +3,64 @@
 /* eslint-disable no-unused-vars */
 /* eslint-disable no-undef */
 /* eslint-disable no-restricted-globals */
-const version = 'v0.3.0';
-const cacheName = 'simorghCache_v1';
-
-const service = self.location.pathname.split('/')[1];
-const hasOfflinePageFunctionality = false;
-const OFFLINE_PAGE = `/${service}/offline`;
-
-self.addEventListener('install', event => {
-  event.waitUntil(async () => {
-    const cache = await caches.open(cacheName);
-    if (hasOfflinePageFunctionality) await cache.add(OFFLINE_PAGE);
-  });
-});
+
+const version = 'v0.3.2';
+// Update cache name when changing caching logic / changes in offlinepage.tsx
+const cacheName = 'simorghCache_v2';
+const pwaClients = new Map();
+let isPWADeviceOffline = false;
+
+// --------------------
+// Helper Functions
+// --------------------
+const loggerEnabled = true;
+const logger = (...args) => {
+  if (!loggerEnabled) return;
+  // eslint-disable-next-line no-console
+  console.log(`[SW ${version}]`, ...args);
+};
+
+const getServiceFromUrl = url => new URL(url).pathname.split('/')[1];
+const getOfflinePageUrl = service => `/${service}/offline`;
+
+const cacheResource = async (cache, url) => {
+  try {
+    const response = await fetch(url);
+    if (response.ok) await cache.put(url, response.clone());
+    return response;
+  } catch (err) {
+    logger(`Failed to cache ${url}:`, err);
+    return null;
+  }
+};
+
+const cacheOfflinePageAndResources = async service => {
+  const cache = await caches.open(cacheName);
+  const offlinePageUrl = new URL(
+    getOfflinePageUrl(service),
+    self.location.origin,
+  ).href;
+
+  if (await cache.match(offlinePageUrl)) return;
+
+  const resp = await cacheResource(cache, offlinePageUrl);
+  if (!resp || !resp.ok) return;
+
+  logger(`Cached offline page for ${service}`);
+
+  const html = await resp.text();
+  const scriptSrcs = [
+    ...html.matchAll(/<script[^>]+src=["']([^"']+)["']/g),
+  ].map(m => m[1]);
+  const linkHrefs = [...html.matchAll(/<link[^>]+href=["']([^"']+)["']/g)].map(
+    m => m[1],
+  );
+
+  const resources = [...scriptSrcs, ...linkHrefs].filter(Boolean);
+
+  logger(`Caching final offline resources for ${service}:`, resources);
+  await Promise.allSettled(resources.map(url => cacheResource(cache, url)));
+};
 
 const CACHEABLE_FILES = [
   // Reverb
@@ -35,24 +80,60 @@ const CACHEABLE_FILES = [
 const WEBP_IMAGE =
   /^https:\/\/ichef(\.test)?\.bbci\.co\.uk\/(news|images|ace\/(standard|ws))\/.+.webp$/;
 
+// -------------Install event -------
+self.addEventListener('install', () => {
+  logger(`Installing...`);
+  self.skipWaiting();
+});
+
+// -------Activate Handler-------------
+self.addEventListener('activate', event => {
+  logger(`Activating...`);
+  event.waitUntil(
+    (async () => {
+      const keys = await caches.keys();
+      await Promise.all(
+        keys.map(key => key !== cacheName && caches.delete(key)),
+      );
+      await self.clients.claim();
+    })(),
+  );
+});
+
+// -------Message Event-------------
+self.addEventListener('message', async event => {
+  logger('Message received:', event.data);
+
+  if (event.data?.type === 'PWA_STATUS') {
+    const clientId = event.source.id;
+    const { isPWA } = event.data;
+
+    if (isPWA) {
+      pwaClients.set(clientId, true);
+      const service = getServiceFromUrl(event.source.url);
+      await cacheOfflinePageAndResources(service);
+    }
+  }
+});
+
+// -------Fetch Handler-------------
 const fetchEventHandler = async event => {
+  logger(`[SW FETCH] Request: ${event.request.url}`);
   const isRequestForCacheableFile = CACHEABLE_FILES.some(cacheableFile =>
     new RegExp(cacheableFile).test(event.request.url),
   );
-
   const isRequestForWebpImage = WEBP_IMAGE.test(event.request.url);
+  const isNavigationMode = event.request.mode === 'navigate';
 
   if (isRequestForWebpImage) {
     const req = event.request.clone();
 
     // Inspect the accept header for WebP support
-
     const supportsWebp =
       req.headers.has('accept') && req.headers.get('accept').includes('webp');
 
     // if supports webp is false in request header then don't use it
     // if accept header doesn't indicate support for webp remove .webp extension
-
     if (!supportsWebp) {
       const imageUrlWithoutWebp = req.url.replace('.webp', '');
       event.respondWith(
@@ -73,22 +154,66 @@ const fetchEventHandler = async event => {
         return response;
       })(),
     );
-  } else if (hasOfflinePageFunctionality && event.request.mode === 'navigate') {
-    event.respondWith(async () => {
-      try {
-        const preloadResponse = await event.preloadResponse;
-        if (preloadResponse) {
-          return preloadResponse;
+  } else if (isNavigationMode) {
+    const { url } = event.request;
+
+    event.respondWith(
+      (async () => {
+        const client = await self.clients.get(event.clientId);
+        const isPWA = client && pwaClients.get(client.id);
+        const cache = await caches.open(cacheName);
+
+        // TODO: Used for testing - to be removed
+        logger('📌 [SW FETCH] Navigation', {
+          url: event.request.url,
+          clientId: event.clientId,
+          isPWA,
+          client,
+          event,
+          pwaClients,
+          isPWADeviceOffline,
+        });
+        try {
+          // Use preload if available
+          const preloadResp = await event.preloadResponse;
+          if (preloadResp) return preloadResp;
+
+          const networkResp = await fetch(event.request);
+          isPWADeviceOffline = false;
+          return networkResp;
+        } catch (err) {
+          // Only show offline page for installed PWA
+          if (isPWA) {
+            const service = getServiceFromUrl(url);
+            const offlineUrl = new URL(
+              getOfflinePageUrl(service),
+              self.location.origin,
+            ).href;
+
+            const cachedOffline = await cache.match(offlineUrl);
+            if (cachedOffline) {
+              isPWADeviceOffline = true;
+              logger('[SW] Serving cached offline page');
+              return cachedOffline;
+            }
+          }
+          // fallback to browser default behavior
+          throw err;
         }
-        const networkResponse = await fetch(event.request);
-        return networkResponse;
-      } catch (error) {
+      })(),
+    );
+  } else if (isPWADeviceOffline) {
+    logger(`[SW v${version}] Serving isPWADeviceOffline ${event.request.url}`);
+    event.respondWith(
+      (async () => {
         const cache = await caches.open(cacheName);
-        const cachedResponse = await cache.match(OFFLINE_PAGE);
-        return cachedResponse;
-      }
-    });
+        const cached = await cache.match(event.request);
+        if (cached) return cached;
+        return fetch(event.request);
+      })(),
+    );
   }
+
   return;
 };
 

src/app/components/ATIAnalytics/canonical/index.tsx

@@ -13,6 +13,7 @@ import usePWAInstallTracker from '#app/hooks/usePWAInstallTracker';
 import { reverbUrlHelper } from '@bbc/reverb-url-helper';
 import useConnectionBackOnlineTracker from '#app/hooks/useConnectionBackOnlineTracker';
 import useConnectionTypeTracker from '#app/hooks/useConnectionTypeTracker';
+import usePWAOfflineTracking from '#app/hooks/usePWAOfflineTracking';
 import { ATIAnalyticsProps } from '../types';
 import getNoScriptTrackingPixelUrl from './getNoScriptTrackingPixelUrl';
 import sendPageViewBeaconOperaMini from './sendPageViewBeaconOperaMini';
@@ -47,6 +48,7 @@ const CanonicalATIAnalytics = ({ reverbParams }: ATIAnalyticsProps) => {
 
   useConnectionTypeTracker();
   useConnectionBackOnlineTracker();
+  usePWAOfflineTracking();
 
   const [reverbBeaconConfig] = useState(reverbParams);
 

src/app/components/ServiceWorker/index.test.tsx

@@ -1,79 +1,38 @@
-import onClient from '#app/lib/utilities/onClient';
+import useServiceWorkerRegistration from '#app/hooks/useServiceWorkerRegistration';
+import useSendPWAStatus from '#app/hooks/useSendPWAStatus';
+import useIsPWA from '#app/hooks/useIsPWA';
 import isLocal from '#app/lib/utilities/isLocal';
-import { render } from '../react-testing-library-with-providers';
-import { ServiceContext } from '../../contexts/ServiceContext';
 import ServiceWorkerContainer from './index';
+import { ServiceContext } from '../../contexts/ServiceContext';
+import { render } from '../react-testing-library-with-providers';
+
+jest.mock('#app/hooks/useServiceWorkerRegistration', () => jest.fn());
+jest.mock('#app/hooks/useSendPWAStatus', () => jest.fn());
+jest.mock('#app/hooks/useIsPWA', () => jest.fn());
+jest.mock('#app/lib/utilities/isLocal', () => jest.fn());
 
 const contextStub = {
-  swPath: '/articles/sw.js',
+  swPath: '/news/sw.js',
   service: 'news',
 };
 
-const mockServiceWorker = {
-  register: jest.fn(),
-};
-
-jest.mock('#app/lib/utilities/onClient', () =>
-  jest.fn().mockImplementation(() => true),
-);
-
-jest.mock('#app/lib/utilities/isLocal', () =>
-  jest.fn().mockImplementation(() => true),
-);
-
-describe('Service Worker', () => {
-  const originalNavigator = global.navigator;
-
-  afterEach(() => {
-    jest.resetAllMocks();
-
-    global.navigator ??= originalNavigator;
+describe('ServiceWorkerContainer', () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+    (useIsPWA as jest.Mock).mockReturnValue(false);
+    (isLocal as jest.Mock).mockReturnValue(true);
   });
 
   describe('Canonical', () => {
-    it('is registered when swPath, serviceWorker have values and onClient is true', () => {
-      // @ts-expect-error need to override the navigator.serviceWorker for testing purposes
-      global.navigator.serviceWorker = mockServiceWorker;
-      (onClient as jest.Mock).mockImplementationOnce(() => true);
-
+    it('calls service worker registration hook with service', () => {
       render(
         // @ts-expect-error only require a subset of properties on service context for testing purposes
-        <ServiceContext.Provider value={{ ...contextStub }}>
+        <ServiceContext.Provider value={contextStub}>
           <ServiceWorkerContainer />
         </ServiceContext.Provider>,
       );
-      expect(navigator.serviceWorker.register).toHaveBeenCalledWith(
-        `/news/articles/sw.js`,
-      );
-    });
-
-    describe('is not registered', () => {
-      it.each`
-        swPath                | serviceWorker        | isOnClient
-        ${undefined}          | ${undefined}         | ${true}
-        ${undefined}          | ${undefined}         | ${false}
-        ${undefined}          | ${mockServiceWorker} | ${true}
-        ${undefined}          | ${mockServiceWorker} | ${false}
-        ${contextStub.swPath} | ${mockServiceWorker} | ${false}
-      `(
-        'when swPath is $swPath, serviceWorker is $serviceWorker and isOnClient is $isOnClient',
-        ({ swPath, serviceWorker, isOnClient }) => {
-          if (serviceWorker) {
-            // @ts-expect-error need to override the navigator.serviceWorker for testing purposes
-            global.navigator.serviceWorker = serviceWorker;
-          }
 
-          (onClient as jest.Mock).mockImplementationOnce(() => isOnClient);
-
-          render(
-            // @ts-expect-error only require a subset of properties on service context for testing purposes
-            <ServiceContext.Provider value={{ ...contextStub, swPath }}>
-              <ServiceWorkerContainer />
-            </ServiceContext.Provider>,
-          );
-          expect(navigator.serviceWorker.register).not.toHaveBeenCalled();
-        },
-      );
+      expect(useServiceWorkerRegistration).toHaveBeenCalledWith('news');
     });
   });
 
@@ -120,4 +79,32 @@ describe('Service Worker', () => {
       );
     });
   });
+
+  describe('PWA', () => {
+    it('calls useSendPWAStatus with true when PWA is installed', () => {
+      (useIsPWA as jest.Mock).mockReturnValue(true);
+
+      render(
+        // @ts-expect-error only require a subset of properties on service context for testing purposes
+        <ServiceContext.Provider value={contextStub}>
+          <ServiceWorkerContainer />
+        </ServiceContext.Provider>,
+      );
+
+      expect(useSendPWAStatus).toHaveBeenCalledWith(true);
+    });
+
+    it('calls useSendPWAStatus with false when PWA is not installed', () => {
+      (useIsPWA as jest.Mock).mockReturnValue(false);
+
+      render(
+        // @ts-expect-error only require a subset of properties on service context for testing purposes
+        <ServiceContext.Provider value={contextStub}>
+          <ServiceWorkerContainer />
+        </ServiceContext.Provider>,
+      );
+
+      expect(useSendPWAStatus).toHaveBeenCalledWith(false);
+    });
+  });
 });