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我在我的支持脱机浏览的渐进式Web应用程序中使用了Cache-first策略。我已经注意到，离线浏览工作正常，但当我更新网站上的内容时，它仍然显示旧的东西。我不知道我的代码有什么问题，因为我想在加载离线前检查是否有更新内容。我有manifest.json的，服务的worker.js，Offlinepage.js和main.js。Cache-First策略中内容更改时网站未更新
这里是我的服务worker.js代码，我已经使用：
//service worker configuration
'use strict';
const
version = '1.0.0',
CACHE = version + '::PWA',
offlineURL = '/offline/',
installFilesEssential = [
'/',
'/manifest.json',
'/theme/pizza/css/style.css',
'/theme/pizza/css/font-awesome/font-awesome.css',
'/theme/pizza/javascript/script.js',
'/theme/pizza/javascript/offlinepage.js',
'/theme/pizza/logo.png',
'/theme/pizza/icon.png'
].concat(offlineURL),
installFilesDesirable = [
'/favicon.ico',
'/theme/pizza/logo.png',
'/theme/pizza/icon.png'
];
// install static assets
function installStaticFiles() {
return caches.open(CACHE)
.then(cache => {
// cache desirable files
cache.addAll(installFilesDesirable);
// cache essential files
return cache.addAll(installFilesEssential);
});
}
// clear old caches
function clearOldCaches() {
return caches.keys()
.then(keylist => {
return Promise.all(
keylist
.filter(key => key !== CACHE)
.map(key => caches.delete(key))
);
});
}
// application installation
self.addEventListener('install', event => {
console.log('service worker: install');
// cache core files
event.waitUntil(
installStaticFiles()
.then(() => self.skipWaiting())
);
});
// application activated
self.addEventListener('activate', event => {
console.log('service worker: activate');
// delete old caches
event.waitUntil(
clearOldCaches()
.then(() => self.clients.claim())
);
});
// is image URL?
let iExt = ['png', 'jpg', 'jpeg', 'gif', 'webp', 'bmp'].map(f => '.' + f);
function isImage(url) {
return iExt.reduce((ret, ext) => ret || url.endsWith(ext), false);
}
// return offline asset
function offlineAsset(url) {
if (isImage(url)) {
// return image
return new Response(
'<svg role="img" viewBox="0 0 400 300" xmlns="http://www.w3.org/2000/svg"><title>offline</title><path d="M0 0h400v300H0z" fill="#eee" /><text x="200" y="150" text-anchor="middle" dominant-baseline="middle" font-family="sans-serif" font-size="50" fill="#ccc">offline</text></svg>',
{ headers: {
'Content-Type': 'image/svg+xml',
'Cache-Control': 'no-store'
}}
);
}
else {
// return page
return caches.match(offlineURL);
}
}
// application fetch network data
self.addEventListener('fetch', event => {
// abandon non-GET requests
if (event.request.method !== 'GET') return;
let url = event.request.url;
event.respondWith(
caches.open(CACHE)
.then(cache => {
return cache.match(event.request)
.then(response => {
if (response) {
// return cached file
console.log('cache fetch: ' + url);
return response;
}
// make network request
return fetch(event.request)
.then(newreq => {
console.log('network fetch: ' + url);
if (newreq.ok) cache.put(event.request, newreq.clone());
return newreq;
})
// app is offline
.catch(() => offlineAsset(url));
});
})
);
});
看起来你服务从缓存中的网页，即使用户处于联机状态。我只会将解决方案应用于离线用户。因此，当他们再次上线时，我们可以清除缓存并提供有效的页面。 –
@DmitriyNesteryuk你是对的。我真的想要一种方法来确保所有用户获得最新的数据并确保页面加载更快 –