Move serviceworker to workbox and fix SSE interference

Instead of statically hardcoding every frontend asset, this uses a
type-based approach to cache all js,css and manifest.json requests.

This also fixes the issue that the service worker was interfering with
EventSource because it was unconditionally handling all requests which
this new implementation doesn't.

Fixes: #11092
Fixes: #7372

Author: silverwind

package-lock.json

@@ -48,6 +48,8 @@
     "webpack": "4.43.0",
     "webpack-cli": "3.3.11",
     "webpack-fix-style-only-entries": "0.4.0",
+    "workbox-routing": "5.1.3",
+    "workbox-strategies": "5.1.3",
     "worker-loader": "2.0.0"
   },
   "devDependencies": {

package.json

@@ -1048,10 +1048,6 @@ func RegisterRoutes(m *macaron.Macaron) {
 		ctx.HTML(200, "pwa/manifest_json")
 	})
 
-	m.Get("/serviceworker.js", templates.JSRenderer(), func(ctx *context.Context) {
-		ctx.HTML(200, "pwa/serviceworker_js")
-	})
-
 	// prometheus metrics endpoint
 	if setting.Metrics.Enabled {
 		c := metrics.NewCollector()

routers/routes/routes.go

@@ -6,30 +6,6 @@
 	<meta http-equiv="x-ua-compatible" content="ie=edge">
 	<title>{{if .Title}}{{.Title | RenderEmojiPlain}} - {{end}} {{if .Repository.Name}}{{.Repository.Name}} - {{end}}{{AppName}} </title>
 	<link rel="manifest" href="{{AppSubUrl}}/manifest.json" crossorigin="use-credentials">
-	{{if UseServiceWorker}}
-	<script>
-		if ('serviceWorker' in navigator) {
-			navigator.serviceWorker.register('{{AppSubUrl}}/serviceworker.js').then(function(registration) {
-				// Registration was successful
-				console.info('ServiceWorker registration successful with scope: ', registration.scope);
-			}, function(err) {
-				// registration failed :(
-				console.info('ServiceWorker registration failed: ', err);
-			});
-		}
-	</script>
-	{{else}}
-	<script>
-		if ('serviceWorker' in navigator) {
-			navigator.serviceWorker.getRegistrations().then(function(registrations) {
-				registrations.forEach(function(registration) {
-					registration.unregister();
-					console.info('ServiceWorker unregistered');
-				});
-			});
-		}
-	</script>
-	{{end}}
 	<meta name="theme-color" content="{{ThemeColorMetaTag}}">
 	<meta name="author" content="{{if .Repository}}{{.Owner.Name}}{{else}}{{MetaAuthor}}{{end}}" />
 	<meta name="description" content="{{if .Repository}}{{.Repository.Name}}{{if .Repository.Description}} - {{.Repository.Description}}{{end}}{{else}}{{MetaDescription}}{{end}}" />
@@ -86,6 +62,7 @@
 		window.config = {
 			AppSubUrl: '{{AppSubUrl}}',
 			StaticUrlPrefix: '{{StaticUrlPrefix}}',
+			UseServiceWorker: {{UseServiceWorker}},
 			csrf: '{{.CsrfToken}}',
 			HighlightJS: {{if .RequireHighlightJS}}true{{else}}false{{end}},
 			Minicolors: {{if .RequireMinicolors}}true{{else}}false{{end}},

templates/base/head.tmpl

@@ -0,0 +1,24 @@
+const {UseServiceWorker, AppSubUrl} = window.config;
+
+async function unregister() {
+  for (const registration of await navigator.serviceWorker.getRegistrations()) {
+    const serviceWorker = registration.active;
+    if (!serviceWorker) continue;
+    registration.unregister();
+  }
+}
+
+export default async function initServiceWorker() {
+  if (!('serviceWorker' in navigator)) return;
+
+  if (UseServiceWorker) {
+    try {
+      navigator.serviceWorker.register(`${AppSubUrl}/serviceworker.js`);
+    } catch (err) {
+      console.error(err);
+      await unregister();
+    }
+  } else {
+    await unregister();
+  }
+}

templates/pwa/serviceworker_js.tmpl

@@ -14,6 +14,7 @@ import initGitGraph from './features/gitgraph.js';
 import initClipboard from './features/clipboard.js';
 import initUserHeatmap from './features/userheatmap.js';
 import initDateTimePicker from './features/datetimepicker.js';
+import initServiceWorker from './features/serviceworker.js';
 import attachTribute from './features/tribute.js';
 import createDropzone from './features/dropzone.js';
 import highlight from './features/highlight.js';
@@ -2475,6 +2476,7 @@ $(document).ready(async () => {
     initGitGraph(),
     initClipboard(),
     initUserHeatmap(),
+    initServiceWorker(),
   ]);
 });
 

web_src/js/features/serviceworker.js

@@ -0,0 +1,14 @@
+import {registerRoute} from 'workbox-routing';
+import {StaleWhileRevalidate} from 'workbox-strategies';
+
+const cachedDestinations = new Set([
+  'manifest',
+  'script',
+  'style',
+  'worker',
+]);
+
+registerRoute(
+  ({request}) => cachedDestinations.has(request.destination),
+  new StaleWhileRevalidate({cacheName: 'static-cache-v2'}),
+);

web_src/js/index.js

@@ -35,13 +35,20 @@ module.exports = {
     jquery: [
       resolve(__dirname, 'web_src/js/jquery.js'),
     ],
+    serviceworker: [
+      resolve(__dirname, 'web_src/js/serviceworker.js'),
+    ],
     icons: glob('node_modules/@primer/octicons/build/svg/**/*.svg'),
     ...themes,
   },
   devtool: false,
   output: {
     path: resolve(__dirname, 'public'),
-    filename: 'js/[name].js',
+    filename: ({chunk}) => {
+      // serviceworker can only manage assets below it's script path so we
+      // have to put it in / instead of /js/
+      return chunk.id === 'serviceworker' ? '[name].js' : 'js/[name].js';
+    },
     chunkFilename: 'js/[name].js',
   },
   optimization: {