ServiceWorker should cache non-local attachments to cache.

packages/gallery/src/app.js

@@ -24,9 +24,9 @@ if (location.protocol !== 'https:' && (!crypto.subtle || !crypto.subtle.digest)
 	location.assign(url);
 } else if ('serviceWorker' in navigator && window.top === window) {
 	navigator.serviceWorker
-		.register('/assets/sw.bundle.js', { scope: '/' })
+		.register('/sw.bundle.js', { scope: '/' })
 		.then(go)
-		.catch(go);
+		.catch(err => console.log(err));
 } else {
 	go();
 }

packages/gallery/src/sw.js

@@ -1,39 +1,63 @@
 import { FileType } from './data/file.js';
 import { log } from './services/console.js';
 
-const http404 = url => () => {
+const VERSION = 'v1';
-	log(`ServiceWorker could not find ${url}`);
+
+function http404() {
 	return new Response(null, {
 		status: 404,
 		statusText: 'NOT FOUND',
 		headers: {}
 	});
-};
+}
+
+function blobAsResponse(blob) {
+	return new Response(blob, {
+		status: 200,
+		statusText: 'OK',
+		headers: {
+			'Content-Type': blob.type
+		}
+	});
+}
 
 self.addEventListener('fetch', event => {
 	const requestUrl = new URL(event.request.url);
 
 	if (requestUrl.pathname && requestUrl.pathname.startsWith('/file/')) {
 		event.respondWith(
-			FileType.getFromURL(requestUrl.pathname)
+			caches
-				.then(data => {
+				.match(event.request)
-					if (data) {
+				.then(resp => {
+					if (resp) {
+						log(`ServiceWorker serving ${requestUrl.pathname} from cache.`);
+						return resp;
+					}
+					return FileType.getFromURL(requestUrl.pathname).then(blob => {
+						if (blob) {
 							log(
-							`ServiceWorker serving ${requestUrl.pathname} ${data.type} ${(data.size / 1024).toFixed(
+								`ServiceWorker serving ${requestUrl.pathname} ${blob.type} ${(blob.size / 1024).toFixed(
 									2
 								)}kb`
 							);
-						return new Response(data, {
+							return blobAsResponse(blob);
-							status: 200,
-							statusText: 'OK',
-							headers: {
-								'Content-Type': data.type
 						}
+						throw new NotFoundError(requestUrl.pathname);
 					});
-					}
-					return http404(requestUrl.pathname)();
 				})
-				.catch(http404(requestUrl.pathname))
+				.then(resp => {
+					if (!FileType.db.$attachmentsProxied) {
+						return resp;
+					}
+					return caches
+						.open(VERSION)
+						.then(cache => cache.put(event.request, resp.clone()))
+						.then(_ => resp);
+				})
+				.catch(err => {
+					log(`ServiceWorker could not access ${requestUrl.pathname}`, err);
+					return http404();
+				})
 		);
 	}
 });

packages/gallery/src/utils/attachmentProxy.js

@@ -13,7 +13,9 @@ async function readStorageMap(blob) {
 }
 
 export function PouchDBAttachmentProxy({ save, getFn, remove }) {
-	const override = {};
+	const override = {
+		$attachmentsProxied: true
+	};
 
 	if (getFn) {
 		override.getAttachment = async function getAttachment(...args) {