Use sw-precache to generate service worker

package.json

@@ -34,6 +34,7 @@
     "eslint-config-airbnb-base": "^2.0.0",
     "eslint-plugin-import": "^1.7.0",
     "html-minifier": "^2.1.2",
+    "sw-precache": "^3.2.0",
     "vulcanize": "^1.14.8",
     "webpack": "^2.1.0-beta.7"
   }

script/sw-precache.js

@@ -0,0 +1,52 @@
+/*
+Generate a caching service worker for HA
+
+Will be called as part of build_frontend.
+
+Expects home-assistant-polymer repo as submodule of HA repo.
+Creates a caching service worker based on the CURRENT content of HA repo.
+Output service worker to build/service_worker.js
+*/
+var crypto = require('crypto');
+var fs = require('fs');
+var path = require('path');
+var swPrecache = require('sw-precache');
+
+var rootDir = '..';
+
+function md5(filename) {
+  return crypto.createHash('md5')
+    .update(fs.readFileSync(filename)).digest('hex');
+}
+
+var appPaths = ['/', '/states', '/logbook', '/history', '/map',
+    '/devService', '/devState', '/devEvent', '/devInfo', '/devTemplate'];
+var fingerprinted = ['frontend', 'mdi'];
+
+var dynamicUrlToDependencies = {};
+
+appPaths.forEach(ap => {
+  dynamicUrlToDependencies[ap] = [rootDir + '/frontend.html'];
+});
+
+fingerprinted.forEach(fn => {
+  var hash = md5(rootDir + '/' + fn + '.html');
+  var url = '/static/' + fn + '-' + hash + '.html';
+  var fpath = rootDir + '/' + fn + '.html';
+  dynamicUrlToDependencies[url] = [fpath];
+});
+
+swPrecache.write(path.join('build', 'service_worker.js'), {
+  dynamicUrlToDependencies: dynamicUrlToDependencies,
+  staticFileGlobs: [
+    rootDir + '/favicon-192x192.png',
+    rootDir + '/webcomponents-lite.min.js',
+    rootDir + '/fonts/roboto/Roboto-Light.ttf',
+    rootDir + '/fonts/roboto/Roboto-Medium.ttf',
+    rootDir + '/fonts/roboto/Roboto-Regular.ttf',
+    rootDir + '/fonts/roboto/Roboto-Bold.ttf',
+    rootDir + '/images/card_media_player_bg.png',
+  ],
+  stripPrefix: '..',
+  replacePrefix: 'static',
+});

src/service-worker/index.js

@@ -1,63 +0,0 @@
-/* eslint-disable no-console */
-const CACHE = '0.10';
-const INDEX_CACHE_URL = '/';
-const INDEX_ROUTES = ['/', '/logbook', '/history', '/map', '/devService', '/devState',
-                      '/devEvent', '/devInfo', '/states'];
-const CACHE_URLS = [
-  '/static/favicon-192x192.png',
-];
-
-if (__DEV__) {
-  console.log('Service Worker initialized.');
-}
-
-self.addEventListener('install', event => {
-  if (__DEV__) {
-    console.log('Service Worker installed.');
-  }
-
-  event.waitUntil(
-    caches.open(CACHE).then(cache => cache.addAll(CACHE_URLS.concat(INDEX_CACHE_URL)))
-  );
-});
-
-self.addEventListener('activate', event => {
-  if (__DEV__) {
-    console.log('Service Worker activated.');
-    // Force refresh service worker
-    event.waitUntil(global.clients.claim());
-  }
-});
-
-self.addEventListener('message', event => {
-  if (__DEV__) {
-    console.log('Message received', event.data);
-  }
-});
-
-self.addEventListener('fetch', event => {
-  const path = event.request.url.substr(event.request.url.indexOf('/', 8));
-
-  // TODO: do not cache requests to 3rd party hosts (or remove those calls)
-
-  if (CACHE_URLS.includes(path)) {
-    event.respondWith(
-      caches.open(CACHE).then(cache => cache.match(event.request))
-    );
-  }
-
-  if (!INDEX_ROUTES.includes(path)) {
-    return;
-  }
-
-  event.respondWith(
-    caches.open(CACHE).then(cache =>
-      cache.match(INDEX_CACHE_URL).then(cachedResponse =>
-        cachedResponse || fetch(event.request).then(response => {
-          cache.put(INDEX_CACHE_URL, response.clone());
-          return response;
-        })
-      )
-    )
-  );
-});

webpack.config.js

@@ -9,7 +9,6 @@ var definePlugin = new webpack.DefinePlugin({
 module.exports = {
   entry: {
     _app_compiled: './src/home-assistant.js',
-    service_worker: './src/service-worker/index.js',
   },
   output: {
     path: 'build',