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1 | /* =========================================================== |
2 | * docsify sw.js |
3 | * =========================================================== |
4 | * Copyright 2016 @huxpro |
5 | * Licensed under Apache 2.0 |
6 | * Register service worker. |
7 | * ========================================================== */ |
8 | |
9 | const RUNTIME = 'docsify' |
10 | const HOSTNAME_WHITELIST = [ |
11 | self.location.hostname, |
12 | 'fonts.gstatic.com', |
13 | 'fonts.googleapis.com', |
14 | 'unpkg.com' |
15 | ] |
16 | |
17 | // The Util Function to hack URLs of intercepted requests |
18 | const getFixedUrl = (req) => { |
19 | var now = Date.now() |
20 | var url = new URL(req.url) |
21 | |
22 | // 1. fixed http URL |
23 | // Just keep syncing with location.protocol |
24 | // fetch(httpURL) belongs to active mixed content. |
25 | // And fetch(httpRequest) is not supported yet. |
26 | url.protocol = self.location.protocol |
27 | |
28 | // 2. add query for caching-busting. |
29 | // Github Pages served with Cache-Control: max-age=600 |
30 | // max-age on mutable content is error-prone, with SW life of bugs can even extend. |
31 | // Until cache mode of Fetch API landed, we have to workaround cache-busting with query string. |
32 | // Cache-Control-Bug: https://bugs.chromium.org/p/chromium/issues/detail?id=453190 |
33 | if (url.hostname === self.location.hostname) { |
34 | url.search += (url.search ? '&' : '?') + 'cache-bust=' + now |
35 | } |
36 | return url.href |
37 | } |
38 | |
39 | /** |
40 | * @Lifecycle Activate |
41 | * New one activated when old isnt being used. |
42 | * |
43 | * waitUntil(): activating ====> activated |
44 | */ |
45 | self.addEventListener('activate', event => { |
46 | event.waitUntil(self.clients.claim()) |
47 | }) |
48 | |
49 | /** |
50 | * @Functional Fetch |
51 | * All network requests are being intercepted here. |
52 | * |
53 | * void respondWith(Promise<Response> r) |
54 | */ |
55 | self.addEventListener('fetch', event => { |
56 | // Skip some of cross-origin requests, like those for Google Analytics. |
57 | if (HOSTNAME_WHITELIST.indexOf(new URL(event.request.url).hostname) > -1) { |
58 | // Stale-while-revalidate |
59 | // similar to HTTP's stale-while-revalidate: https://www.mnot.net/blog/2007/12/12/stale |
60 | // Upgrade from Jake's to Surma's: https://gist.github.com/surma/eb441223daaedf880801ad80006389f1 |
61 | const cached = caches.match(event.request) |
62 | const fixedUrl = getFixedUrl(event.request) |
63 | const fetched = fetch(fixedUrl, { cache: 'no-store' }) |
64 | const fetchedCopy = fetched.then(resp => resp.clone()) |
65 | |
66 | // Call respondWith() with whatever we get first. |
67 | // If the fetch fails (e.g disconnected), wait for the cache. |
68 | // If there’s nothing in cache, wait for the fetch. |
69 | // If neither yields a response, return offline pages. |
70 | event.respondWith( |
71 | Promise.race([fetched.catch(_ => cached), cached]) |
72 | .then(resp => resp || fetched) |
73 | .catch(_ => { /* eat any errors */ }) |
74 | ) |
75 | |
76 | // Update the cache with the version we fetched (only for ok status) |
77 | event.waitUntil( |
78 | Promise.all([fetchedCopy, caches.open(RUNTIME)]) |
79 | .then(([response, cache]) => response.ok && cache.put(event.request, response)) |
80 | .catch(_ => { /* eat any errors */ }) |
81 | ) |
82 | } |
83 | }) |