feat: port updated service worker code to develop, allow plugins to define scripts to import into service worker

public/src/service-worker.js

@@ -1,5 +1,15 @@
 'use strict';
 
+self.addEventListener('install', () => {
+	// Register self as the primary service worker
+	self.skipWaiting();
+});
+
+self.addEventListener('activate', (event) => {
+	// Take responsibility over existing clients from old service worker
+	event.waitUntil(self.clients.claim());
+});
+
 self.addEventListener('fetch', function (event) {
 	// This is the code that ignores post requests
 	// https://github.com/NodeBB/NodeBB/issues/9151

src/routes/meta.js

@@ -1,8 +1,11 @@
 'use strict';
 
+const { readFile, access, constants } = require('fs/promises');
 const path = require('path');
 const nconf = require('nconf');
 
+const plugins = require('../plugins');
+
 module.exports = function (app, middleware, controllers) {
 	app.get('/sitemap.xml', controllers.sitemap.render);
 	app.get('/sitemap/pages.xml', controllers.sitemap.getPages);
@@ -12,10 +15,43 @@ module.exports = function (app, middleware, controllers) {
 	app.get('/manifest.webmanifest', controllers.manifest);
 	app.get('/css/previews/:theme', controllers.admin.themes.get);
 	app.get('/osd.xml', controllers.osd.handle);
-	app.get('/service-worker.js', (req, res) => {
+	app.get('/service-worker.js', async (req, res) => {
+		const swPath = path.join(__dirname, '../../build/public/src/service-worker.js');
+		let swContents = await readFile(swPath, { encoding: 'utf-8' });
+
 		res.status(200)
 			.type('application/javascript')
-			.set('Service-Worker-Allowed', `${nconf.get('relative_path')}/`)
-			.sendFile(path.join(__dirname, '../../build/public/src/service-worker.js'));
+			.set('Service-Worker-Allowed', `${nconf.get('relative_path')}/`);
+
+		/**
+		 * Allow plugins to append their own scripts for the service worker to import
+		 * expects: URLs in passed-in Set, either absolute or relative to plugin static directory root (/assets/plugins)
+		 * see: https://docs.nodebb.org/development/plugins/statics
+		 */
+		let scripts = new Set();
+		({ scripts } = await plugins.hooks.fire('filter:service-worker.scripts', { scripts }));
+
+		if (!scripts.size) {
+			res.sendFile(swPath);
+		} else {
+			const urls = await Promise.all(Array
+				.from(scripts)
+				.map(async (pathname) => {
+					try {
+						const url = new URL(pathname, `${nconf.get('url')}/assets/plugins/`);
+						if (url.href.startsWith(nconf.get('url'))) {
+							const fullPath = path.resolve(__dirname, '../../build/public/plugins', url.pathname.replace(`${nconf.get('relative_path')}/assets/plugins/`, ''));
+							await access(fullPath, constants.R_OK);
+						}
+						return url;
+					} catch (e) {
+						return null;
+					}
+				}));
+
+			const payload = urls.map(urlObj => urlObj.href).join("', '");
+			swContents += `\nimportScripts('${payload}')`;
+			res.send(swContents);
+		}
 	});
 };