| /* =========================================================== |
| * docsify sw.js |
| * =========================================================== |
| * Copyright 2016 @huxpro |
| * Licensed under Apache 2.0 |
| * Register service worker. |
| * ========================================================== */ |
| |
| const RUNTIME = 'docsify' |
| const HOSTNAME_WHITELIST = [ |
| self.location.hostname, |
| 'fonts.gstatic.com', |
| 'fonts.googleapis.com', |
| 'unpkg.com' |
| ] |
| |
| // The Util Function to hack URLs of intercepted requests |
| const getFixedUrl = (req) => { |
| var now = Date.now() |
| var url = new URL(req.url) |
| |
| // 1. fixed http URL |
| // Just keep syncing with location.protocol |
| // fetch(httpURL) belongs to active mixed content. |
| // And fetch(httpRequest) is not supported yet. |
| url.protocol = self.location.protocol |
| |
| // 2. add query for caching-busting. |
| // Github Pages served with Cache-Control: max-age=600 |
| // max-age on mutable content is error-prone, with SW life of bugs can even extend. |
| // Until cache mode of Fetch API landed, we have to workaround cache-busting with query string. |
| // Cache-Control-Bug: https://bugs.chromium.org/p/chromium/issues/detail?id=453190 |
| if (url.hostname === self.location.hostname) { |
| url.search += (url.search ? '&' : '?') + 'cache-bust=' + now |
| } |
| return url.href |
| } |
| |
| /** |
| * @Lifecycle Activate |
| * New one activated when old isnt being used. |
| * |
| * waitUntil(): activating ====> activated |
| */ |
| self.addEventListener('activate', event => { |
| event.waitUntil(self.clients.claim()) |
| }) |
| |
| /** |
| * @Functional Fetch |
| * All network requests are being intercepted here. |
| * |
| * void respondWith(Promise<Response> r) |
| */ |
| self.addEventListener('fetch', event => { |
| // Skip some of cross-origin requests, like those for Google Analytics. |
| if (HOSTNAME_WHITELIST.indexOf(new URL(event.request.url).hostname) > -1) { |
| // Stale-while-revalidate |
| // similar to HTTP's stale-while-revalidate: https://www.mnot.net/blog/2007/12/12/stale |
| // Upgrade from Jake's to Surma's: https://gist.github.com/surma/eb441223daaedf880801ad80006389f1 |
| const cached = caches.match(event.request) |
| const cachedDelayed = new Promise(function(resolve, reject) { |
| setTimeout(resolve, 500, cached); |
| }); |
| const fixedUrl = getFixedUrl(event.request) |
| const fetched = fetch(fixedUrl, { cache: 'no-store' }) |
| const fetchedCopy = fetched.then(resp => resp.clone()) |
| |
| if (navigator.onLine) { |
| // Call respondWith() with whatever we get first. |
| // If the fetch fails (e.g disconnected), wait for the cache. |
| // If there’s nothing in cache, wait for the fetch. |
| // If neither yields a response, return offline pages. |
| event.respondWith( |
| Promise.race([fetched.catch(_ => cached), cachedDelayed]) |
| .then(resp => resp || fetched) |
| .catch(_ => { /* eat any errors */ }) |
| ) |
| } |
| else { // offline |
| event.respondWith( |
| Promise.resolve(cached) |
| .then(resp => resp) |
| .catch(_ => { /* eat any errors */ }) |
| ) |
| } |
| |
| // Update the cache with the version we fetched (only for ok status) |
| event.waitUntil( |
| Promise.all([fetchedCopy, caches.open(RUNTIME)]) |
| .then(([response, cache]) => response.ok && cache.put(event.request, response)) |
| .catch(_ => { /* eat any errors */ }) |
| ) |
| } |
| }) |