Add a serviceworker (#234)

* Add a serviceworker

* rename + fix random extra character

* Fixing worker typings

* Fixing types properly this time.

* Once of those rare cases where this matters.

* Naming the things.

* Move registration to the app (so we can use snackbar later)

* Moving SW plugin later so it picks up things like HTML

* MVP service worker

* Two stage-service worker

* Fix prerendering by conditionally awaiting Custom Elements polyfill.

* Fix icon 404's

* add doc comment to autoswplugin

* Fix type

src/codecs/decoders.ts

@@ -1,9 +1,8 @@
 import { nativeDecode, sniffMimeType, canDecodeImage } from '../lib/util';
 import Processor from './processor';
+import webpDataUrl from 'url-loader!./tiny.webp';
 
-// tslint:disable-next-line:max-line-length It’s a data URL. Whatcha gonna do?
-const webpFile = 'data:image/webp;base64,UklGRh4AAABXRUJQVlA4TBEAAAAvAAAAAAfQ//73v/+BiOh/AAA=';
-const nativeWebPSupported = canDecodeImage(webpFile);
+const nativeWebPSupported = canDecodeImage(webpDataUrl);
 
 export async function decodeImage(blob: Blob, processor: Processor): Promise<ImageData> {
   const mimeType = await sniffMimeType(blob);

src/codecs/processor-worker.ts

@@ -7,31 +7,46 @@ import { EncodeOptions as WebPEncoderOptions } from './webp/encoder-meta';
 async function mozjpegEncode(
   data: ImageData, options: MozJPEGEncoderOptions,
 ): Promise<ArrayBuffer> {
-  const { encode } = await import('./mozjpeg/encoder');
+  const { encode } = await import(
+    /* webpackChunkName: "process-mozjpeg-enc" */
+    './mozjpeg/encoder',
+  );
   return encode(data, options);
 }
 
 async function quantize(data: ImageData, opts: QuantizeOptions): Promise<ImageData> {
-  const { process } = await import('./imagequant/processor');
+  const { process } = await import(
+    /* webpackChunkName: "process-imagequant" */
+    './imagequant/processor',
+  );
   return process(data, opts);
 }
 
 async function optiPngEncode(
   data: BufferSource, options: OptiPNGEncoderOptions,
 ): Promise<ArrayBuffer> {
-  const { compress } = await import('./optipng/encoder');
+  const { compress } = await import(
+    /* webpackChunkName: "process-optipng" */
+    './optipng/encoder',
+  );
   return compress(data, options);
 }
 
 async function webpEncode(
   data: ImageData, options: WebPEncoderOptions,
 ): Promise<ArrayBuffer> {
-  const { encode } = await import('./webp/encoder');
+  const { encode } = await import(
+    /* webpackChunkName: "process-webp-enc" */
+    './webp/encoder',
+  );
   return encode(data, options);
 }
 
 async function webpDecode(data: ArrayBuffer): Promise<ImageData> {
-  const { decode } = await import('./webp/decoder');
+  const { decode } = await import(
+    /* webpackChunkName: "process-webp-dec" */
+    './webp/decoder',
+  );
   return decode(data);
 }
 

src/codecs/processor.ts

@@ -61,7 +61,10 @@ export default class Processor {
           // worker-loader does magic here.
           // @ts-ignore - Typescript doesn't know about the 2nd param to new Worker, and the
           // definition can't be overwritten.
-          this._worker = new Worker('./processor-worker.ts', { type: 'module' }) as Worker;
+          this._worker = new Worker(
+            './processor-worker.ts',
+            { name: 'processor-worker', type: 'module' },
+          ) as Worker;
           // Need to do some TypeScript trickery to make the type match.
           this._workerApi = proxy(this._worker) as any as ProcessorWorkerApi;
         }

src/components/App/index.tsx

@@ -36,12 +36,17 @@ export default class App extends Component<Props, State> {
   constructor() {
     super();
 
-    import('../compress').then((module) => {
+    import(
+      /* webpackChunkName: "main-app" */
+      '../compress',
+    ).then((module) => {
       this.setState({ Compress: module.default });
     }).catch(() => {
       this.showSnack('Failed to load app');
     });
 
+    navigator.serviceWorker.register('../../sw');
+
     // In development, persist application state across hot reloads:
     if (process.env.NODE_ENV === 'development') {
       this.setState(window.STATE);

src/components/compress/index.tsx

@@ -1,4 +1,5 @@
 import { h, Component } from 'preact';
+import { get, set } from 'idb-keyval';
 
 import { bind, Fileish } from '../../lib/initial-util';
 import { blobToImg, drawableToImageData, blobToText } from '../../lib/util';
@@ -155,6 +156,12 @@ async function processSvg(blob: Blob): Promise<HTMLImageElement> {
   return blobToImg(new Blob([newSource], { type: 'image/svg+xml' }));
 }
 
+async function getOldestServiceWorker() {
+  const reg = await navigator.serviceWorker.getRegistration();
+  if (!reg) return null;
+  return reg.active || reg.waiting || reg.installing;
+}
+
 // These are only used in the mobile view
 const resultTitles = ['Top', 'Bottom'];
 // These are only used in the desktop view
@@ -195,6 +202,17 @@ export default class Compress extends Component<Props, State> {
     super(props);
     this.widthQuery.addListener(this.onMobileWidthChange);
     this.updateFile(props.file);
+
+    // If this is the first time the user has interacted with the app, tell the service worker to
+    // cache all the codecs.
+    get<boolean | undefined>('user-interacted')
+      .then(async (userInteracted: boolean | undefined) => {
+        if (userInteracted) return;
+        set('user-interacted', true);
+        const serviceWorker = await getOldestServiceWorker();
+        if (!serviceWorker) return; // Service worker not installing yet.
+        serviceWorker.postMessage('cache-all');
+      });
   }
 
   @bind

src/components/intro/index.tsx

@@ -4,13 +4,13 @@ import { bind, linkRef, Fileish } from '../../lib/initial-util';
 import '../custom-els/LoadingSpinner';
 
 import logo from './imgs/logo.svg';
-import largePhoto from './imgs/demos/large-photo.jpg';
-import artwork from './imgs/demos/artwork.jpg';
-import deviceScreen from './imgs/demos/device-screen.png';
-import largePhotoIcon from './imgs/demos/large-photo-icon.jpg';
-import artworkIcon from './imgs/demos/artwork-icon.jpg';
-import deviceScreenIcon from './imgs/demos/device-screen-icon.jpg';
-import logoIcon from './imgs/demos/logo-icon.png';
+import largePhoto from './imgs/demos/demo-large-photo.jpg';
+import artwork from './imgs/demos/demo-artwork.jpg';
+import deviceScreen from './imgs/demos/demo-device-screen.png';
+import largePhotoIcon from './imgs/demos/icon-demo-large-photo.jpg';
+import artworkIcon from './imgs/demos/icon-demo-artwork.jpg';
+import deviceScreenIcon from './imgs/demos/icon-demo-device-screen.jpg';
+import logoIcon from './imgs/demos/icon-demo-logo.png';
 import * as style from './style.scss';
 import SnackBarElement from '../../lib/SnackBar';
 

src/index.html

@@ -8,6 +8,7 @@
     <meta name="mobile-web-app-capable" content="yes">
     <meta name="apple-mobile-web-app-capable" content="yes">
     <meta name="theme-color" content="#673ab8">
+    <link rel="shortcut icon" href="/assets/favicon.ico">
     <link rel="manifest" href="/manifest.json">
   </head>
   <body>

src/index.ts

@@ -1,9 +1,14 @@
 declare module '@webcomponents/custom-elements';
 
-(async function () {
-  if (!('customElements' in self)) {
-    await import('@webcomponents/custom-elements');
-  }
-
+function init() {
   require('./init-app.tsx');
-})();
+}
+
+if (!('customElements' in self)) {
+  import(
+    /* webpackChunkName: "wc-polyfill" */
+    '@webcomponents/custom-elements',
+  ).then(init);
+} else {
+  init();
+}

src/init-app.tsx

@@ -9,8 +9,7 @@ let root = document.querySelector('#app') || undefined;
 // "attach" the client-side rendering to it, updating the DOM in-place instead of replacing:
 root = render(<App />, document.body, root);
 
-// In production, this entire condition is removed.
-if (process.env.NODE_ENV === 'development') {
+if (process.env.NODE_ENV !== 'production') {
   // Enable support for React DevTools and some helpful console warnings:
   require('preact/debug');
 

src/manifest.json

@@ -8,9 +8,9 @@
   "theme_color": "#673ab8",
   "icons": [
     {
-      "src": "/assets/icon.png",
+      "src": "/assets/icon-large.png",
       "type": "image/png",
-      "sizes": "512x512"
+      "sizes": "1024x1024"
     }
   ]
-}
+}

src/missing-types.d.ts

@@ -27,3 +27,8 @@ declare module '*.wasm' {
   const content: string;
   export default content;
 }
+
+declare module 'url-loader!*' {
+  const value: string;
+  export default value;
+}

src/sw/index.ts

@@ -0,0 +1,63 @@
+import {
+  cacheOrNetworkAndCache, cleanupCache, cacheOrNetwork, cacheBasics, cacheAdditionalProcessors,
+} from './util';
+import { get } from 'idb-keyval';
+
+// Give TypeScript the correct global.
+declare var self: ServiceWorkerGlobalScope;
+// This is populated by webpack.
+declare var BUILD_ASSETS: string[];
+
+const version = '1.0.0';
+const versionedCache = 'static-' + version;
+const dynamicCache = 'dynamic';
+const expectedCaches = [versionedCache, dynamicCache];
+
+self.addEventListener('install', (event) => {
+  event.waitUntil(async function () {
+    const promises = [];
+    promises.push(cacheBasics(versionedCache, BUILD_ASSETS));
+
+    // If the user has already interacted with the app, update the codecs too.
+    if (await get('user-interacted')) {
+      promises.push(cacheAdditionalProcessors(versionedCache, BUILD_ASSETS));
+    }
+
+    await Promise.all(promises);
+  }());
+});
+
+self.addEventListener('activate', (event) => {
+  event.waitUntil(async function () {
+    // Remove old caches.
+    const promises = (await caches.keys()).map((cacheName) => {
+      if (!expectedCaches.includes(cacheName)) return caches.delete(cacheName);
+    });
+
+    await Promise.all<any>(promises);
+  }());
+});
+
+self.addEventListener('fetch', (event) => {
+  // We only care about GET.
+  if (event.request.method !== 'GET') return;
+
+  const url = new URL(event.request.url);
+
+  // Don't care about other-origin URLs
+  if (url.origin !== location.origin) return;
+
+  if (url.pathname.startsWith('/demo-') || url.pathname.startsWith('/wc-polyfill')) {
+    cacheOrNetworkAndCache(event, dynamicCache);
+    cleanupCache(event, dynamicCache, BUILD_ASSETS);
+    return;
+  }
+
+  cacheOrNetwork(event);
+});
+
+self.addEventListener('message', (event) => {
+  if (event.data === 'cache-all') {
+    event.waitUntil(cacheAdditionalProcessors(versionedCache, BUILD_ASSETS));
+  }
+});

src/sw/missing-types.d.ts

@@ -0,0 +1 @@
+import '../missing-types';

src/sw/tsconfig.json

@@ -0,0 +1,18 @@
+{
+  "compileOnSave": false,
+  "compilerOptions": {
+    "strict": true,
+    "target": "esnext",
+    "module": "esnext",
+    "lib": [
+      "webworker",
+      "esnext"
+    ],
+    "moduleResolution": "node",
+    "experimentalDecorators": true,
+    "noUnusedLocals": true,
+    "sourceMap": true,
+    "allowJs": false,
+    "baseUrl": "."
+  }
+}

src/sw/util.ts

@@ -0,0 +1,105 @@
+import webpDataUrl from 'url-loader!../codecs/tiny.webp';
+
+export function cacheOrNetwork(event: FetchEvent): void {
+  event.respondWith(async function () {
+    const cachedResponse = await caches.match(event.request);
+    return cachedResponse || fetch(event.request);
+  }());
+}
+
+export function cacheOrNetworkAndCache(event: FetchEvent, cacheName: string): void {
+  event.respondWith(async function () {
+    const { request } = event;
+    // Return from cache if possible.
+    const cachedResponse = await caches.match(request);
+    if (cachedResponse) return cachedResponse;
+
+    // Else go to the network.
+    const response = await fetch(request);
+    const responseToCache = response.clone();
+
+    event.waitUntil(async function () {
+      // Cache what we fetched.
+      const cache = await caches.open(cacheName);
+      await cache.put(request, responseToCache);
+    }());
+
+    // Return the network response.
+    return response;
+  }());
+}
+
+export function cleanupCache(event: FetchEvent, cacheName: string, keepAssets: string[]) {
+  event.waitUntil(async function () {
+    const cache = await caches.open(cacheName);
+
+    // Clean old entries from the dynamic cache.
+    const requests = await cache.keys();
+    const promises = requests.map((cachedRequest) => {
+      // Get pathname without leading /
+      const assetPath = new URL(cachedRequest.url).pathname.slice(1);
+      // If it isn't one of our keepAssets, we don't need it anymore.
+      if (!keepAssets.includes(assetPath)) return cache.delete(cachedRequest);
+    });
+
+    await Promise.all<any>(promises);
+  }());
+}
+
+export async function cacheBasics(cacheName: string, buildAssets: string[]) {
+  const toCache = ['/', '/assets/favicon.ico'];
+
+  const prefixesToCache = [
+    // First interaction JS & CSS:
+    'first-interaction.',
+    // Main app JS & CSS:
+    'main-app.',
+    // Little icons for the demo images on the homescreen:
+    'icon-demo-',
+    // Site logo:
+    'logo.',
+  ];
+
+  const prefixMatches = buildAssets.filter(
+    asset => prefixesToCache.some(prefix => asset.startsWith(prefix)),
+  );
+
+  toCache.push(...prefixMatches);
+
+  const cache = await caches.open(cacheName);
+  await cache.addAll(toCache);
+}
+
+export async function cacheAdditionalProcessors(cacheName: string, buildAssets: string[]) {
+  let toCache = [];
+
+  const prefixesToCache = [
+    // Worker which handles image processing:
+    'processor-worker.',
+    // processor-worker imports:
+    'process-',
+  ];
+
+  const prefixMatches = buildAssets.filter(
+    asset => prefixesToCache.some(prefix => asset.startsWith(prefix)),
+  );
+
+  const wasm = buildAssets.filter(asset => asset.endsWith('.wasm'));
+
+  toCache.push(...prefixMatches, ...wasm);
+
+  const supportsWebP = await (async () => {
+    if (!self.createImageBitmap) return false;
+    const response = await fetch(webpDataUrl);
+    const blob = await response.blob();
+    return createImageBitmap(blob).then(() => true, () => false);
+  })();
+
+  // No point caching the WebP decoder if it's supported natively:
+  if (supportsWebP) {
+    toCache = toCache.filter(asset => !/webp[\-_]dec/.test(asset));
+  }
+
+  const cache = await caches.open(cacheName);
+  await cache.addAll(toCache);
+}