当浏览器在线时,我创建并成功注册了一个Service Worker。我可以使用DevTools查看资源已正确缓存。问题在于,当我切换到离线模式时,Service Worker似乎会注销自己,因此只显示谷歌Chrome离线页面。
代码如下:
'use strict';
var CACHE_NAME = 'v1';
var urlsToCache = [
'/'
];
self.addEventListener('install', function(event) {
// Perform install steps
event.waitUntil(
caches.open(CACHE_NAME)
.then(function(cache) {
console.log('Opened cache');
return cache.addAll(urlsToCache);
})
);
});
self.addEventListener('fetch', function(event) {
event.respondWith(
caches.match(event.request)
.then(function(response) {
// Cache hit - return response
if (response) {
return response;
}
// IMPORTANT: Clone the request. A request is a stream and
// can only be consumed once. Since we are consuming this
// once by cache and once by the browser for fetch, we need
// to clone the response.
var fetchRequest = event.request.clone();
return fetch(fetchRequest).then(
function(response) {
// Check if we received a valid response
if(!response || response.status !== 200 || response.type !== 'basic') {
return response;
}
// IMPORTANT: Clone the response. A response is a stream
// and because we want the browser to consume the response
// as well as the cache consuming the response, we need
// to clone it so we have two streams.
var responseToCache = response.clone();
caches.open(CACHE_NAME)
.then(function(cache) {
cache.put(event.request, responseToCache);
});
return response;
}
);
})
);
});
如果有帮助的话,这是测试脚本。
'use strict';
if ('serviceWorker' in navigator) {
navigator.serviceWorker.register('/sw.js').then(function(registration) {
// Registration was successful
console.log('ServiceWorker registration successful with scope: ', registration.scope);
var serviceWorker;
if (registration.installing) {
serviceWorker = registration.installing;
} else if (registration.waiting) {
serviceWorker = registration.waiting;
} else if (registration.active) {
serviceWorker = registration.active;
}
if (serviceWorker) {
console.log('ServiceWorker phase:', serviceWorker.state);
serviceWorker.addEventListener('statechange', function (e) {
console.log('ServiceWorker phase:', e.target.state);
});
}
}).catch(function(err) {
// registration failed :(
console.log('ServiceWorker registration failed: ', err);
});
}
编辑:检查控制台后,我发现了这个错误:
sw.js:1 在获取脚本时发生未知错误。
另外,根据建议,我已经添加了这段代码,但问题仍然存在。this.addEventListener('activate', function(event) {
var cacheWhitelist = ['v2'];
event.waitUntil(
caches.keys().then(function(keyList) {
return Promise.all(keyList.map(function(key) {
if (cacheWhitelist.indexOf(key) === -1) {
return caches.delete(key);
}
}));
})
);
});