init project

static/sw.js

@@ -0,0 +1,37 @@
+const CACHE_NAME = 'thumbnail-cache-v1';
+const THUMB_URL_PATTERN = /^\/thumb\//;
+
+self.addEventListener('install', (event) => {
+  self.skipWaiting();
+});
+
+self.addEventListener('activate', (event) => {
+  event.waitUntil(clients.claim());
+});
+
+self.addEventListener('fetch', (event) => {
+  const { request } = event;
+  const url = new URL(request.url);
+  
+  // 只缓存缩略图请求
+  if (THUMB_URL_PATTERN.test(url.pathname)) {
+    event.respondWith(
+      caches.open(CACHE_NAME).then((cache) => {
+        return cache.match(request).then((response) => {
+          // 如果缓存中有响应，直接返回
+          if (response) {
+            return response;
+          }
+          
+          // 否则发起网络请求，并将响应添加到缓存中
+          return fetch(request).then((networkResponse) => {
+            // 复制响应，因为流只能读取一次
+            const responseToCache = networkResponse.clone();
+            cache.put(request, responseToCache);
+            return networkResponse;
+          });
+        });
+      })
+    );
+  }
+});