https://www.uk-cpa.org/sw.js

1/*global self, caches */
2
3// This is the service worker code that lives at the root (sw.js)
4'use strict';
5
6// You have to supply a name for your cache, this will
7// allow us to remove an old one to avoid hitting disk
8// space limits and displaying old resources
9var cacheName = 'v1';
10
11// Change for your sitemap's path if that's what
12// you'll use to get your blog's pages
13var sitemapUrl = '';
14
15// Assets to cache
16// The items to cache at this point should be something you don't forsee
17// changing often, such as base styles, scripts, fonts, logos, etc.
18var assetsToCache = [
19	'/assets/styles/css/style.css',
20	'/assets/scripts/min/fatkit.min.js'
21	// Add any image files you might need here too
22];
23
24self.addEventListener('install', function(event)
25{
26
27	// waitUntil() ensures that the Service Worker will not
28	// install until the code inside has successfully occurred
29	event.waitUntil(
30		// Create cache with the name supplied above and
31		// return a promise for it
32		caches.open(cacheName).then(function(cache)
33		{
34
35			if(sitemapUrl !== '')
36			{
37
38				// Add all assets to cache
39				cache.addAll(assetsToCache);
40
41				// Get your blog's pages and add them to cache
42	      		cachePages(cache);
43
44	      	} else {
45
46				// Important to `return` the promise here to have `skipWaiting()`
47				// fire after the cache has been updated.
48	      		return cache.addAll(assetsToCache);
49
50	      	}
51
52		})
53		.then(function ()
54		{
55
56			// `skipWaiting()` forces the waiting ServiceWorker to become the
57			// active ServiceWorker, triggering the `onactivate` event.
58			// Together with `Clients.claim()` this allows a worker to take effect
59			// immediately in the client(s).
60			return self.skipWaiting();
61
62		})
63		.catch(function(e)
64		{
65
66			console.error('[FatKit] Service worker error occured when trying to add files to cache. Do the files specified in the assetsToCache array (in sw.js) exist? Error:', e);
67
68		})
69	);
70
71});
72
73// Activate event
74// Be sure to call self.clients.claim()
75self.addEventListener('activate', function(event)
76{
77
78	// `claim()` sets this worker as the active worker for all clients that
79	// match the workers scope and triggers an `oncontrollerchange` event for
80	// the clients.
81	return self.clients.claim();
82
83});
84
85function cachePages(cache)
86{
87
88	// Get sitemap and return the text response
89	fetch(sitemapUrl).then(function(response)
90	{
91
92		return response.text();
93
94	}).then(function(text)
95	{
96
97		// Regex to match xml locations (URLs)
98		var pattern = /<loc>(.+?)</g;
99		// Get all matches within the text
100		var urls = getMatches(text, pattern);
101		// Add them to the previously opened cache
102		cache.addAll(urls);
103
104	});
105
106}
107
108// Simple function to get multiple matched groups
109function getMatches(string, regex)
110{
111
112	var matches = [];
113	var match;
114	while(match = regex.exec(string))
115	{
116
117		matches.push(match[1]);
118
119	}
120	return matches;
121
122}
123
124self.addEventListener('fetch', function(event)
125{
126
127	// Get current path
128	var requestUrl = new URL(event.request.url);
129
130	// Ignore non-get request like when accessing the admin panel
131	if(event.request.method !== 'GET')
132	{
133		return;
134	}
135
136	// Don't try to handle non-secure assets because fetch will fail
137	if(/http:/.test(event.request.url))
138	{
139		return;
140	}
141
142	// Don't try and cache the umbraco back end
143	if(/umbraco/.test(event.request.url))
144	{
145		return
146	}
147
148	// Ignore certain file types
149	// Necessary for PDFs (and maybe others), as service workers won't fetch files in an <embed> or <object> tag,
150	// but browsers may use these tags with their native file viewers (eg, Chrome's PDF viewer uses embed)
151	// Reference: https://www.chromestatus.com/feature/6313531834105856
152	var ignoreFileExtensions = [ 'pdf' ];
153
154	var fileExtRegex = /\.([A-z]*)$/gm;
155	var fileExtMatch = fileExtRegex.exec(requestUrl.pathname);
156
157	if (fileExtMatch && ignoreFileExtensions.includes(fileExtMatch[1]))
158	{
159		console.log(`[FatKit] Service worker ignored this ${fileExtMatch[1].toUpperCase()} file: `, requestUrl.href);
160		return;
161	}
162
163	// Save all resources on origin path only, or img.fat.dev images
164	if(requestUrl.origin === location.origin || requestUrl.origin === "https://img.fat.dev")
165	{
166
167		// To cache specific page check it here
168		// if(requestUrl.pathname === '/')
169		// {
170
171		// Here's where we cache all the things!
172		event.respondWith(
173			// Open the cache created when install
174			caches.open(cacheName).then(function(cache)
175			{
176
177				// Go to the network to ask for that resource

178				return fetch(event.request).then(function(networkResponse)
179				{
180
181					// .NET returns a vary header of '*' under certain
182					// scenarios, which is invalid for putting in the cache
183					var varyHeader = networkResponse.headers.get('vary');
184					if (varyHeader === '*') {
185						return networkResponse;
186					}
187
188					// Add a copy of the response to the cache (updating the old version)
189					cache.put(event.request, networkResponse.clone());
190
191					// Respond with it
192					return networkResponse;
193
194				}).catch(function()
195				{
196
197					// If there is no internet connection, try to match the request
198					// to some of our cached resources
199					return cache.match(event.request);
200
201				});
202
203			})
204		);
205
206	// }
207
208	}
209
210});