From 4a917971d0cd21b23788eb40a71f4ef100dfc0a5 Mon Sep 17 00:00:00 2001
From: Julien Oculi <xdrz.jot.sr@gmail.com>
Date: Thu, 18 Jul 2024 14:18:26 +0200
Subject: [PATCH] feat(pwa): :zap: split pre-cache and dynamic cache in service
 worker

---
 src/serviceworker/mod.ts | 74 ++++++++++++++++++++++------------------
 1 file changed, 41 insertions(+), 33 deletions(-)

diff --git a/src/serviceworker/mod.ts b/src/serviceworker/mod.ts
index 2e78d54..ff3eaec 100644
--- a/src/serviceworker/mod.ts
+++ b/src/serviceworker/mod.ts
@@ -31,19 +31,21 @@ const swStorage = {
 }
 
 async function getPreCachedUrls(): Promise<string[]> {
-	const raw = await swStorage.getItem<string[]>('$sw.cache.urls')
+	const raw = await swStorage.getItem<string[]>('$sw.pre-cache.urls')
+
 	if (raw === null) {
-		await openCache()
+		await openPreCache()
 		return getPreCachedUrls()
 	}
 	return raw
 }
 
-async function getCache(): Promise<Cache> {
-	const version = await swStorage.getItem<string>('$sw.cache.version')
+async function getPreCache(): Promise<Cache> {
+	const version = await swStorage.getItem<string>('$sw.pre-cache.version')
+	// Get cache from server
 	if (version === null) {
-		await openCache()
-		return getCache()
+		await openPreCache()
+		return getPreCache()
 	}
 	return caches.open(version)
 }
@@ -52,7 +54,7 @@ const IS_SW = 'onpushsubscriptionchange' in self
 if (IS_SW) {
 	self.addEventListener('install', (event) => {
 		// Assign global cache and pre-cached-urls
-		event.waitUntil(openCache())
+		event.waitUntil(openPreCache())
 	})
 
 	self.addEventListener('activate', () => {
@@ -85,18 +87,22 @@ if (IS_SW) {
 async function fetchHandler(event: FetchEvent) {
 	const url = new URL(event.request.url)
 	const method = event.request.method
+
 	const preCachedUrls = await getPreCachedUrls()
-	const cache = await getCache()
-	// Cache will be updated on each request if version change
-	updateCache()
 
 	// Cache first for "pre-cached-urls"
 	if (preCachedUrls.includes(url.pathname) && method === 'GET') {
-		const cached = await cache.match(event.request) ??
+		const preCache = await getPreCache()
+
+		// Cache request update on each request if version change
+		updatePreCache()
+
+		// TODO handle search params
+		const cached = await preCache.match(event.request) ??
 			await fetch(event.request).then((response) =>
 				response.ok ? response : null
 			).catch(() => null) ??
-			await cache.match(event.request, { ignoreSearch: true })
+			await preCache.match(event.request, { ignoreSearch: true })
 
 		if (cached === undefined) {
 			throw new Error(`no cache available for pre-cached-url "${url}"`)
@@ -119,39 +125,41 @@ async function fetchHandler(event: FetchEvent) {
 				cache.put(event.request, response.clone())
 				return response
 			})
-			.catch((cause) => {
-				// Try serve cache if no network
-				if (cached === undefined) {
-					throw new Error(`no cache available for "${url}"`, { cause })
-				}
-				return cached
-			})
-
-		if (cached === undefined) {
-			return response
-		}
-
-		return cached
+async function getDynCache(): Promise<Cache> {
+	const version = await swStorage.getItem<number>('$sw.dyn-cache.version')
+	// Create cache
+	if (version === null) {
+		await swStorage.setItem<number>('$sw.dyn-cache.version', now + lifeTime)
+		return getDynCache()
 	}
 
+	// Clean outdated cache
+	if (version < Date.now()) {
+		await swStorage.setItem<number>('$sw.dyn-cache.version', now + lifeTime)
+		await caches.delete(version.toString())
+		return getDynCache()
+	}
+
+	return cache
+}
+
 	// Network only
 	return fetch(event.request)
 }
 
-async function updateCache() {
-	const serverVersion = await getServerCacheVersion()
-	const clientVersion = await swStorage.getItem<string>('$sw.cache.version')
+	const serverVersion = await getServerPreCacheVersion()
+	const clientVersion = await swStorage.getItem<string>('$sw.pre-cache.version')
 	if (clientVersion === null) return
 	if (serverVersion === undefined) return
 	if (clientVersion === serverVersion) return
 
 	// Open new pre-cache
-	await openCache()
+	await openPreCache()
 	// Delete old pre-cache
 	caches.delete(clientVersion)
 }
 
-async function getServerCacheVersion() {
+async function getServerPreCacheVersion(): Promise<string | undefined> {
 	const response = await fetch('/api/serviceworker/precache').then(
 		(response) => response.json() as Promise<ApiPayload<PrecacheResponse>>,
 	)
@@ -161,7 +169,7 @@ async function getServerCacheVersion() {
 	}
 }
 
-async function openCache() {
+async function openPreCache() {
 	const response = await fetch('/api/serviceworker/precache').then(
 		(response) => response.json() as Promise<ApiPayload<PrecacheResponse>>,
 	)
@@ -183,8 +191,8 @@ async function openCache() {
 	}
 	await Promise.allSettled(addList)
 
-	await swStorage.setItem('$sw.cache.version', version)
-	await swStorage.setItem('$sw.cache.urls', preCachedUrls)
+	await swStorage.setItem('$sw.pre-cache.version', version)
+	await swStorage.setItem('$sw.pre-cache.urls', preCachedUrls)
 
 	return { cache, version, preCachedUrls }
 }