忙活了半天终于把网站的 Service Worker 缓存配置给弄好了。（暑假放假的第一天就折腾这些，下个月我就是高三学生了）
之前(一直)觉得网站的速度不够快，总要等好几秒才加载完，背景图总是卡下才加载好。我已经尽自己能力把网络加载速度弄到最大了（在不换主题不删功能的条件下），首次加载已经做到最快加载了。也把我能控制地资源全加上了 cache-control 响应头，但第二次打开总有些图片啊、js啊没缓存，比如图片的白一下才显示出来。
今天就去折腾 Service Worker 了，使得博客的访问速度德到大大的提升，虽然不知为何有时图片等突然变得加载很慢，但总的来说比之前快了不少。
Service Worker 的代码我贴在这了，可以用作参考。
const swconfig = {
CACHE_VERSION: "v2.0",
runtimeCaching: [
// {
// urlPattern: /^https:\/\/cdn\.example\.com\/.*/,
// handler: "CacheFirst",
// maxAgeSeconds: 60 * 60 * 24 * 365
// },
// {
// urlPattern: /https:\/\/blog.ksable.top\//gi,
// handler: "NetworkFirst",
// maxAgeSeconds: 60 * 60 * 24 * 7
// },
{
urlPattern: RegExp('^https://www.favicon.vip/get.php'),
handler: "CacheFirst",
maxAgeSeconds: 60 * 60 * 24 * 365
},
{
urlPattern: RegExp('^https://image.thum.io/'),
handler: "CacheFirst",
maxAgeSeconds: 60 * 60 * 24 * 30
},
{
urlPattern: /https?:\/\/[^\/]+\/.*\.(png|jpg|jpeg|gif|svg|ico|woff2|ttf|js|css?)(\?.*)?/,
handler: "CacheFirst",
maxAgeSeconds: 60 * 60 * 24 * 365
},
{
urlPattern: /^https:\/\/ik.imagekit.io\//,
handler: "CacheFirst",
maxAgeSeconds: 0
},
{
urlPattern: /^https:\/\/weavatar.com\/avatar\//,
handler: "CacheFirst",
maxAgeSeconds: 60 * 60 * 24 * 30
},
{
urlPattern: /^https:\/\/assets.ksable.top\/js\/my-js.js/,
handler: "CacheFirst",
maxAgeSeconds: 60 * 60 * 24 * 1
}
],
exclude: [
/^https:\/\/blog.ksable.top\/sw.js/gi
],
precacheUrls: [
'/content.json', // 预缓存的内容JSON文件
'/offline.html' // 离线页面
]
};
const CACHE_NAME = `${swconfig.CACHE_VERSION}-cache`;
const CACHE_META_KEY = 'cache-meta';
const OFFLINE_URL = '/offline.html';
// 匹配请求对应的规则
function matchRule(request) {
const url = request.url;
// 检查排除规则
for (const pattern of swconfig.exclude) {
if (pattern.test(url)) return null;
}
// 反向遍历确保后面的规则优先级更高
for (let i = swconfig.runtimeCaching.length - 1; i >= 0; i--) {
const rule = swconfig.runtimeCaching[i];
if (rule.urlPattern.test(url)) {
return rule;
}
}
return null;
}
// 获取缓存元数据
async function getCacheMeta() {
const cache = await caches.open(CACHE_NAME);
const response = await cache.match(CACHE_META_KEY);
return response ? await response.json() : {};
}
// 更新缓存元数据
async function updateCacheMeta(url, timestamp) {
const cache = await caches.open(CACHE_NAME);
const meta = await getCacheMeta();
meta[url] = {
timestamp,
cachedAt: Date.now()
};
await cache.put(
CACHE_META_KEY,
new Response(JSON.stringify(meta), {
headers: { 'Content-Type': 'application/json' }
})
);
}
// 后台更新缓存
async function backgroundUpdate(request, rule) {
try {
const cache = await caches.open(CACHE_NAME);
const cachedResponse = await cache.match(request);
if (!cachedResponse) return;
// 准备验证头
const headers = new Headers();
const etag = cachedResponse.headers.get('ETag');
const lastModified = cachedResponse.headers.get('Last-Modified');
if (etag) headers.set('If-None-Match', etag);
if (lastModified) headers.set('If-Modified-Since', lastModified);
// 发送验证请求
const networkResponse = await fetch(request, {
headers,
cache: 'no-cache'
});
if (networkResponse.status === 304) { // 未修改
await updateCacheMeta(request.url, Date.now());
} else if (networkResponse.ok) { // 资源已更新
const responseClone = networkResponse.clone();
await cache.put(request, responseClone);
await updateCacheMeta(request.url, Date.now());
}
} catch (error) {
console.error('Background update failed:', error);
}
}
// 安装阶段 - 初始化缓存
self.addEventListener('install', event => {
event.waitUntil(
caches.open(CACHE_NAME).then(cache => {
// 初始化缓存元数据
return cache.put(
CACHE_META_KEY,
new Response('{}', {
headers: { 'Content-Type': 'application/json' }
})
).then(() => {
// 预缓存关键资源
return cache.addAll(swconfig.precacheUrls);
});
}).then(() => self.skipWaiting())
);
});
// 激活阶段 - 清理旧缓存
self.addEventListener('activate', event => {
event.waitUntil(
caches.keys().then(cacheNames => {
return Promise.all(
cacheNames.map(name => {
if (name !== CACHE_NAME && name.startsWith('v')) {
return caches.delete(name);
}
})
);
}).then(() => self.clients.claim())
);
});
// 请求处理
self.addEventListener('fetch', event => {
const request = event.request;
// 只处理GET请求
if (request.method !== 'GET') return;
// 特殊处理导航请求的离线回退
if (request.mode === 'navigate') {
event.respondWith(
(async () => {
try {
// 首先尝试网络请求
const networkResponse = await fetch(request);
return networkResponse;
} catch (error) {
// 网络失败时返回离线页面
const offlineResponse = await caches.match(OFFLINE_URL);
if (offlineResponse) {
return offlineResponse;
}
// 如果离线页面也未缓存，返回简单错误响应
return new Response('Offline', {
status: 503,
statusText: 'Service Unavailable'
});
}
})()
);
return;
}
// 匹配缓存规则
const rule = matchRule(request);
if (!rule) return;
// 处理不同缓存策略
switch (rule.handler) {
case 'NetworkOnly':
event.respondWith(fetch(request));
break;
case 'CacheOnly':
event.respondWith(
caches.match(request).then(response => response || Response.error())
);
break;
case 'NetworkFirst':
event.respondWith(
fetch(request).catch(() => caches.match(request))
);
break;
case 'CacheFirst':
default:
event.respondWith((async () => {
const cache = await caches.open(CACHE_NAME);
const cachedResponse = await cache.match(request);
const meta = await getCacheMeta();
const url = request.url;
const metaEntry = meta[url];
// 如果找到缓存
if (cachedResponse) {
// 检查是否需要后台更新
if (rule.maxAgeSeconds > 0 && metaEntry) {
const age = (Date.now() - metaEntry.cachedAt) / 1000;
if (age > rule.maxAgeSeconds) {
// 后台更新不影响当前响应
event.waitUntil(backgroundUpdate(request, rule));
}
}
return cachedResponse;
}
// 没有缓存则请求网络
try {
const networkResponse = await fetch(request);
if (networkResponse.ok) {
const responseClone = networkResponse.clone();
await cache.put(request, responseClone);
await updateCacheMeta(url, Date.now());
}
return networkResponse;
} catch (error) {
return Response.error();
}
})());
break;
}
});
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