Creation

Client/wwwroot/service-worker.published.js

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+// Caution! Be sure you understand the caveats before publishing an application with
+// offline support. See https://aka.ms/blazor-offline-considerations
+
+self.importScripts('./service-worker-assets.js');
+self.addEventListener('install', event => event.waitUntil(onInstall(event)));
+self.addEventListener('activate', event => event.waitUntil(onActivate(event)));
+self.addEventListener('fetch', event => event.respondWith(onFetch(event)));
+
+const cacheNamePrefix = 'offline-cache-';
+const cacheName = `${cacheNamePrefix}${self.assetsManifest.version}`;
+const offlineAssetsInclude = [ /\.dll$/, /\.pdb$/, /\.wasm/, /\.html/, /\.js$/, /\.json$/, /\.css$/, /\.woff$/, /\.png$/, /\.jpe?g$/, /\.gif$/, /\.ico$/, /\.blat$/, /\.dat$/ ];
+const offlineAssetsExclude = [ /^service-worker\.js$/ ];
+
+async function onInstall(event) {
+    console.info('Service worker: Install');
+
+    // Fetch and cache all matching items from the assets manifest
+    const assetsRequests = self.assetsManifest.assets
+        .filter(asset => offlineAssetsInclude.some(pattern => pattern.test(asset.url)))
+        .filter(asset => !offlineAssetsExclude.some(pattern => pattern.test(asset.url)))
+        .map(asset => new Request(asset.url, { integrity: asset.hash, cache: 'no-cache' }));
+    await caches.open(cacheName).then(cache => cache.addAll(assetsRequests));
+}
+
+async function onActivate(event) {
+    console.info('Service worker: Activate');
+
+    // Delete unused caches
+    const cacheKeys = await caches.keys();
+    await Promise.all(cacheKeys
+        .filter(key => key.startsWith(cacheNamePrefix) && key !== cacheName)
+        .map(key => caches.delete(key)));
+}
+
+async function onFetch(event) {
+    let cachedResponse = null;
+    if (event.request.method === 'GET') {
+        // For all navigation requests, try to serve index.html from cache
+        // If you need some URLs to be server-rendered, edit the following check to exclude those URLs
+        const shouldServeIndexHtml = event.request.mode === 'navigate';
+
+        const request = shouldServeIndexHtml ? 'index.html' : event.request;
+        const cache = await caches.open(cacheName);
+        cachedResponse = await cache.match(request);
+    }
+
+    return cachedResponse || fetch(event.request);
+}