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samples/web/web_dashboard/flutter_service_worker.js

191 lines
6.6 KiB

'use strict';
const MANIFEST = 'flutter-app-manifest';
const TEMP = 'flutter-temp-cache';
const CACHE_NAME = 'flutter-app-cache';
const RESOURCES = {
"version.json": "0507ec11c5c92cea90b4f83e2e3b2033",
"firebase_init.js": "622b108cf1fb4d6527c998381e317752",
"main.dart.js": "8d3dc652de935b874d16de487726069c",
"index.html": "18aaf2e497fd84025c8e0d56b518d072",
"/": "18aaf2e497fd84025c8e0d56b518d072",
"assets/packages/cupertino_icons/assets/CupertinoIcons.ttf": "115e937bb829a890521f72d2e664b632",
"assets/AssetManifest.json": "2efbb41d7877d10aac9d091f58ccd7b9",
"assets/NOTICES": "afe69e75529f680d19fe81586cafdc9d",
"assets/fonts/MaterialIcons-Regular.otf": "4e6447691c9509f7acdbf8a931a85ca1",
"assets/FontManifest.json": "dc3d03800ccca4601324923c0b1d6d57",
"icons/Icon-512.png": "96e752610906ba2a93c65f8abe1645f1",
"icons/Icon-192.png": "ac9a721a12bbc803b44f645561ecb1e1",
"manifest.json": "f4c726512ced772dee601da2f29e868f"
};
// The application shell files that are downloaded before a service worker can
// start.
const CORE = [
"/",
"main.dart.js",
"index.html",
"assets/NOTICES",
"assets/AssetManifest.json",
"assets/FontManifest.json"];
// During install, the TEMP cache is populated with the application shell files.
self.addEventListener("install", (event) => {
self.skipWaiting();
return event.waitUntil(
caches.open(TEMP).then((cache) => {
return cache.addAll(
CORE.map((value) => new Request(value, {'cache': 'reload'})));
})
);
});
// During activate, the cache is populated with the temp files downloaded in
// install. If this service worker is upgrading from one with a saved
// MANIFEST, then use this to retain unchanged resource files.
self.addEventListener("activate", function(event) {
return event.waitUntil(async function() {
try {
var contentCache = await caches.open(CACHE_NAME);
var tempCache = await caches.open(TEMP);
var manifestCache = await caches.open(MANIFEST);
var manifest = await manifestCache.match('manifest');
// When there is no prior manifest, clear the entire cache.
if (!manifest) {
await caches.delete(CACHE_NAME);
contentCache = await caches.open(CACHE_NAME);
for (var request of await tempCache.keys()) {
var response = await tempCache.match(request);
await contentCache.put(request, response);
}
await caches.delete(TEMP);
// Save the manifest to make future upgrades efficient.
await manifestCache.put('manifest', new Response(JSON.stringify(RESOURCES)));
return;
}
var oldManifest = await manifest.json();
var origin = self.location.origin;
for (var request of await contentCache.keys()) {
var key = request.url.substring(origin.length + 1);
if (key == "") {
key = "/";
}
// If a resource from the old manifest is not in the new cache, or if
// the MD5 sum has changed, delete it. Otherwise the resource is left
// in the cache and can be reused by the new service worker.
if (!RESOURCES[key] || RESOURCES[key] != oldManifest[key]) {
await contentCache.delete(request);
}
}
// Populate the cache with the app shell TEMP files, potentially overwriting
// cache files preserved above.
for (var request of await tempCache.keys()) {
var response = await tempCache.match(request);
await contentCache.put(request, response);
}
await caches.delete(TEMP);
// Save the manifest to make future upgrades efficient.
await manifestCache.put('manifest', new Response(JSON.stringify(RESOURCES)));
return;
} catch (err) {
// On an unhandled exception the state of the cache cannot be guaranteed.
console.error('Failed to upgrade service worker: ' + err);
await caches.delete(CACHE_NAME);
await caches.delete(TEMP);
await caches.delete(MANIFEST);
}
}());
});
// The fetch handler redirects requests for RESOURCE files to the service
// worker cache.
self.addEventListener("fetch", (event) => {
if (event.request.method !== 'GET') {
return;
}
var origin = self.location.origin;
var key = event.request.url.substring(origin.length + 1);
// Redirect URLs to the index.html
if (key.indexOf('?v=') != -1) {
key = key.split('?v=')[0];
}
if (event.request.url == origin || event.request.url.startsWith(origin + '/#') || key == '') {
key = '/';
}
// If the URL is not the RESOURCE list then return to signal that the
// browser should take over.
if (!RESOURCES[key]) {
return;
}
// If the URL is the index.html, perform an online-first request.
if (key == '/') {
return onlineFirst(event);
}
event.respondWith(caches.open(CACHE_NAME)
.then((cache) => {
return cache.match(event.request).then((response) => {
// Either respond with the cached resource, or perform a fetch and
// lazily populate the cache.
return response || fetch(event.request).then((response) => {
cache.put(event.request, response.clone());
return response;
});
})
})
);
});
self.addEventListener('message', (event) => {
// SkipWaiting can be used to immediately activate a waiting service worker.
// This will also require a page refresh triggered by the main worker.
if (event.data === 'skipWaiting') {
self.skipWaiting();
return;
}
if (event.data === 'downloadOffline') {
downloadOffline();
return;
}
});
// Download offline will check the RESOURCES for all files not in the cache
// and populate them.
async function downloadOffline() {
var resources = [];
var contentCache = await caches.open(CACHE_NAME);
var currentContent = {};
for (var request of await contentCache.keys()) {
var key = request.url.substring(origin.length + 1);
if (key == "") {
key = "/";
}
currentContent[key] = true;
}
for (var resourceKey of Object.keys(RESOURCES)) {
if (!currentContent[resourceKey]) {
resources.push(resourceKey);
}
}
return contentCache.addAll(resources);
}
// Attempt to download the resource online before falling back to
// the offline cache.
function onlineFirst(event) {
return event.respondWith(
fetch(event.request).then((response) => {
return caches.open(CACHE_NAME).then((cache) => {
cache.put(event.request, response.clone());
return response;
});
}).catch((error) => {
return caches.open(CACHE_NAME).then((cache) => {
return cache.match(event.request).then((response) => {
if (response != null) {
return response;
}
throw error;
});
});
})
);
}