mail/src/js/offline-cache.js

91 lines
4.2 KiB
JavaScript

/**
* Copyright 2015 Google Inc. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
'use strict';
var UPDATE_MSG = 'A new version of Whiteout Mail is available. Restart the app to update?';
if ('serviceWorker' in navigator &&
// See http://www.chromium.org/Home/chromium-security/prefer-secure-origins-for-powerful-new-features
(window.location.protocol === 'https:' ||
window.location.hostname === 'localhost' ||
window.location.hostname.indexOf('127.') === 0)) {
// prefer new service worker cache
useServiceWorker();
} else if ('applicationCache' in window) {
// Fall back to app cache
useAppCache();
}
function useServiceWorker() {
// Your service-worker.js *must* be located at the top-level directory relative to your site.
// It won't be able to control pages unless it's located at the same level or higher than them.
// *Don't* register service worker file in, e.g., a scripts/ sub-directory!
// See https://github.com/slightlyoff/ServiceWorker/issues/468
navigator.serviceWorker.register('service-worker.js', {
scope: './'
}).then(function(registration) {
// Check to see if there's an updated version of service-worker.js with new files to cache:
// https://slightlyoff.github.io/ServiceWorker/spec/service_worker/index.html#service-worker-registration-update-method
if (typeof registration.update === 'function') {
registration.update();
}
// updatefound is fired if service-worker.js changes.
registration.onupdatefound = function() {
// The updatefound event implies that registration.installing is set; see
// https://slightlyoff.github.io/ServiceWorker/spec/service_worker/index.html#service-worker-container-updatefound-event
var installingWorker = registration.installing;
installingWorker.onstatechange = function() {
if (installingWorker.state === 'installed') {
if (navigator.serviceWorker.controller) {
// At this point, the old content will have been purged and the fresh content will
// have been added to the cache.
// It's the perfect time to display a "New content is available; please refresh."
// message in the page's interface.
if (window.confirm(UPDATE_MSG)) {
window.location.reload();
}
} else {
// At this point, everything has been precached, but the service worker is not
// controlling the page. The service worker will not take control until the next
// reload or navigation to a page under the registered scope.
// It's the perfect time to display a "Content is cached for offline use." message.
console.log('Content is cached, and will be available for offline use the next time the page is loaded.');
}
}
};
};
}).catch(function(e) {
console.error('Error during service worker registration:', e);
});
}
function useAppCache() {
window.onload = function() {
// Check if a new AppCache is available on page load.
window.applicationCache.onupdateready = function() {
if (window.applicationCache.status === window.applicationCache.UPDATEREADY) {
// Browser downloaded a new app cache
if (window.confirm(UPDATE_MSG)) {
window.location.reload();
}
}
};
};
}