sw.js

/*!
Copyright 2022 ChromeHack Team

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

"use strict";

(() => {
importScripts("/app.js");
importScripts("/uv/uv.sw.js");

const cacheName = `${location.hostname}-${app.cacheName}-${app.cacheVersion}`;
const sw = new UVServiceWorker();

async function install() {
	const cache = await caches.open(cacheName);
	await cache.addAll(app.cacheList);
}

/**
 * @param {Request} request 
 * @param {Response} response 
 */
async function cache(request, response) {
	try {
		const cache = await caches.open(cacheName);
		await cache.put(request, response.clone());
	} catch(err) {
		// ignore - this is usually caused by an unsupported request method
	}
}

/**
 * @param {Request} request 
 */
async function fetchRe(request) {
	let response = await caches.match(request, { cacheName });
	if (response == null) {
		if (request.url.startsWith(sw.prefix)) {
			response = await sw.fetch(request);
		} else {
			response = await fetch(request);
			if (response.status == 0) {
				return response; // cross origin responses
			}
		}

		await cache(request, response);
	}

	const headers = new Headers(response.headers);
	const head = app.headers;
	for (let h in head) {
		headers.set(h, head[h]);
	}

	return new Response(response.body, {
		status: response.status,
		statusText: response.statusText,
		headers
	});
}

async function removeOldCaches() {
	for (let k of await caches.keys()) {
		if (k != cacheName)
			await caches.delete(k);
	}
}

self.addEventListener("install", (event) => {
	event.waitUntil(install());
});

self.addEventListener("fetch", (event) => {
	event.respondWith(fetchRe(event.request));
});

self.addEventListener("activate", (event) => {
	event.waitUntil(removeOldCaches());
});

})();