79 lines
2 KiB
JavaScript
79 lines
2 KiB
JavaScript
import { build, files, version } from '$service-worker';
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// Create a unique cache name for this deployment
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const CACHE = `cache-${version}`;
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const ASSETS = [
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...build, // the app itself
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...files // everything in `static`
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];
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self.addEventListener('install', (event) => {
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// Create a new cache and add all files to it
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async function addFilesToCache() {
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const cache = await caches.open(CACHE);
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await cache.addAll(ASSETS);
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}
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event.waitUntil(addFilesToCache());
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});
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self.addEventListener('activate', (event) => {
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// Remove previous cached data from disk
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async function deleteOldCaches() {
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for (const key of await caches.keys()) {
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if (key !== CACHE) await caches.delete(key);
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}
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}
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event.waitUntil(deleteOldCaches());
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});
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self.addEventListener('fetch', (event) => {
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// ignore POST requests etc
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if (event.request.method !== 'GET' || event.request.pathname === 'download') return;
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async function respond() {
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const url = new URL(event.request.url);
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const cache = await caches.open(CACHE);
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// `build`/`files` can always be served from the cache
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if (ASSETS.includes(url.pathname)) {
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const response = await cache.match(url.pathname);
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if (response) {
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return response;
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}
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}
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// for everything else, try the network first, but
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// fall back to the cache if we're offline
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try {
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const response = await fetch(event.request);
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// if we're offline, fetch can return a value that is not a Response
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// instead of throwing - and we can't pass this non-Response to respondWith
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if (!(response instanceof Response)) {
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throw new Error('invalid response from fetch');
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}
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if (response.status === 200) {
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cache.put(event.request, response.clone());
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}
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return response;
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} catch (err) {
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const response = await cache.match(event.request);
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if (response) {
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return response;
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}
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// if there's no cache, then just error out
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// as there is nothing we can do to respond to this request
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throw err;
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}
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}
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event.respondWith(respond());
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});
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