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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