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+ })
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