feat: add PWA manifest and offline service worker for public pages

build/pwa-vite-plugin.ts

@@ -0,0 +1,160 @@
+import { createHash } from "node:crypto";
+import { readFile, writeFile } from "node:fs/promises";
+import { resolve } from "node:path";
+import type { Plugin } from "vite";
+
+/**
+ * Public files that are not referenced by the page markup but are still needed
+ * for an installed app to start without a network connection.
+ */
+const STATIC_PRECACHE = [
+  "/manifest.webmanifest",
+  "/favicon.ico",
+  "/favicon-32.png",
+  "/favicon-dark.svg",
+  "/apple-touch-icon.png",
+  "/icon-512.png",
+  "/mouse-preview.svg",
+];
+
+/**
+ * Pages whose emitted markup is scanned for the hashed assets to precache.
+ * The license gate and the control app are deliberately absent: both are
+ * verified per request by functions/_middleware.js, so caching either one
+ * would let a revoked license keep working offline.
+ */
+const PRECACHE_PAGES: { file: string; url: string }[] = [
+  { file: "index.html", url: "/" },
+  { file: "demo.html", url: "/demo.html" },
+];
+
+/** Same-origin paths the worker must never serve from its own cache. */
+const BYPASS_SOURCE = [
+  "/^\\/api\\//",
+  "/^\\/control-app/",
+  "/^\\/protected-assets\\//",
+  "/^\\/control(?:\\.html)?$/",
+].join(", ");
+
+function renderServiceWorker(version: string, precache: string[]): string {
+  return `// Generated by build/pwa-vite-plugin.ts. Do not edit by hand.
+const CACHE = "openmouse-${version}";
+const FONT_CACHE = "openmouse-fonts";
+const PRECACHE = ${JSON.stringify(precache, null, 2)};
+
+/**
+ * Licensed routes. These are validated per request by the Cloudflare
+ * middleware and must always reach the network, so an expired or revoked
+ * session cannot be served from a local cache.
+ */
+const BYPASS = [${BYPASS_SOURCE}];
+
+const FONT_ORIGINS = ["https://fonts.googleapis.com", "https://fonts.gstatic.com"];
+
+self.addEventListener("install", (event) => {
+  event.waitUntil(
+    caches.open(CACHE)
+      .then((cache) => cache.addAll(PRECACHE))
+      .then(() => self.skipWaiting()),
+  );
+});
+
+self.addEventListener("activate", (event) => {
+  event.waitUntil(
+    caches.keys()
+      .then((keys) => Promise.all(
+        keys
+          .filter((key) => key !== CACHE && key !== FONT_CACHE)
+          .map((key) => caches.delete(key)),
+      ))
+      .then(() => self.clients.claim()),
+  );
+});
+
+/** Serves the cached copy immediately and refreshes it in the background. */
+async function staleWhileRevalidate(request, cacheName) {
+  const cache = await caches.open(cacheName);
+  const cached = await cache.match(request);
+  const network = fetch(request)
+    .then((response) => {
+      if (response.ok || response.type === "opaque") cache.put(request, response.clone());
+      return response;
+    })
+    .catch(() => cached);
+  return cached ?? network;
+}
+
+/** Prefers fresh markup, falling back to the cache when the network is gone. */
+async function networkFirst(request) {
+  const cache = await caches.open(CACHE);
+  try {
+    const response = await fetch(request);
+    if (response.ok) cache.put(request, response.clone());
+    return response;
+  } catch (error) {
+    const cached = await cache.match(request) ?? await cache.match("/");
+    if (cached) return cached;
+    throw error;
+  }
+}
+
+self.addEventListener("fetch", (event) => {
+  const { request } = event;
+  if (request.method !== "GET") return;
+
+  const url = new URL(request.url);
+
+  if (FONT_ORIGINS.includes(url.origin)) {
+    event.respondWith(staleWhileRevalidate(request, FONT_CACHE));
+    return;
+  }
+
+  if (url.origin !== self.location.origin) return;
+  if (BYPASS.some((pattern) => pattern.test(url.pathname))) return;
+
+  if (request.mode === "navigate") {
+    event.respondWith(networkFirst(request));
+    return;
+  }
+
+  event.respondWith(
+    caches.match(request).then((cached) => cached ?? fetch(request)),
+  );
+});
+`;
+}
+
+/** Emits a service worker that precaches the public pages and their assets. */
+export function pwa(appVersion: string): Plugin {
+  let root = process.cwd();
+  let outputDirectory = "dist";
+
+  return {
+    name: "openmouse-pwa",
+    apply: "build",
+    configResolved(config) {
+      root = config.root;
+      outputDirectory = config.build.outDir;
+    },
+    // Runs against the written output: Vite injects the hashed asset tags into
+    // the markup after generateBundle, so the emitted HTML is only complete on disk.
+    async closeBundle() {
+      const outputRoot = resolve(root, outputDirectory);
+      const urls = new Set<string>(STATIC_PRECACHE);
+
+      for (const page of PRECACHE_PAGES) {
+        const markup = await readFile(resolve(outputRoot, page.file), "utf8");
+
+        urls.add(page.url);
+        for (const [, asset] of markup.matchAll(/(?:href|src)="(\/assets\/[^"]+)"/g)) {
+          urls.add(asset);
+        }
+      }
+
+      const precache = [...urls].sort();
+      const version = `${appVersion}-${createHash("sha256").update(precache.join("\n")).digest("hex").slice(0, 8)}`;
+
+      await writeFile(resolve(outputRoot, "sw.js"), renderServiceWorker(version, precache));
+    },
+  };
+}

demo.html

@@ -8,6 +8,7 @@
     <link rel="icon" type="image/png" href="/favicon-32.png?v=2" sizes="32x32" />
     <link rel="icon" type="image/svg+xml" href="/favicon-dark.svg?v=2" sizes="any" />
     <link rel="apple-touch-icon" href="/apple-touch-icon.png?v=2" sizes="180x180" />
+    <link rel="manifest" href="/manifest.webmanifest" />
     <link rel="preconnect" href="https://fonts.googleapis.com" />
     <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin />
     <link href="https://fonts.googleapis.com/css2?family=DM+Sans:opsz,wght@9..40,400;9..40,500;9..40,600&family=JetBrains+Mono:wght@400;500&display=swap" rel="stylesheet" />

index.html

@@ -11,6 +11,7 @@
     <link rel="icon" type="image/png" href="/favicon-32.png?v=2" sizes="32x32" />
     <link rel="icon" type="image/svg+xml" href="/favicon-dark.svg?v=2" sizes="any" />
     <link rel="apple-touch-icon" href="/apple-touch-icon.png?v=2" sizes="180x180" />
+    <link rel="manifest" href="/manifest.webmanifest" />
     <meta name="description" content="Tune supported gaming mice in your browser, adjust DPI, polling rate, and sensor settings in one place." />
     <meta name="robots" content="index, follow" />
     <link rel="canonical" href="https://openmouse.app/" />

public/manifest.webmanifest

@@ -0,0 +1,36 @@
+{
+  "id": "/",
+  "name": "OpenMouse",
+  "short_name": "OpenMouse",
+  "description": "Manage supported gaming mice in one place — DPI, polling rate, battery, and sensor settings.",
+  "start_url": "/",
+  "scope": "/",
+  "display": "standalone",
+  "background_color": "#09090b",
+  "theme_color": "#09090b",
+  "categories": ["utilities", "productivity"],
+  "icons": [
+    {
+      "src": "/favicon-32.png",
+      "sizes": "32x32",
+      "type": "image/png"
+    },
+    {
+      "src": "/apple-touch-icon.png",
+      "sizes": "180x180",
+      "type": "image/png"
+    },
+    {
+      "src": "/icon-512.png",
+      "sizes": "512x512",
+      "type": "image/png",
+      "purpose": "any"
+    },
+    {
+      "src": "/icon-512.png",
+      "sizes": "512x512",
+      "type": "image/png",
+      "purpose": "maskable"
+    }
+  ]
+}

src/demo.ts

@@ -1,4 +1,7 @@
 import "./demo.css";
+import { registerServiceWorker } from "./register-sw";
+
+registerServiceWorker();
 
 const demoApp = document.querySelector<HTMLDivElement>("#demo-app");
 

src/main.ts

@@ -1,4 +1,7 @@
 import "./styles.css";
+import { registerServiceWorker } from "./register-sw";
+
+registerServiceWorker();
 
 const app = document.querySelector<HTMLDivElement>("#app");
 

src/register-sw.ts

@@ -0,0 +1,15 @@
+/**
+ * Registers the generated service worker so the public pages stay available
+ * without a connection. The worker only exists in a production build, and it
+ * deliberately never caches the licensed control app — see
+ * build/pwa-vite-plugin.ts.
+ */
+export function registerServiceWorker(): void {
+  if (!import.meta.env.PROD || !("serviceWorker" in navigator)) return;
+
+  window.addEventListener("load", () => {
+    void navigator.serviceWorker.register("/sw.js").catch(() => {
+      // Offline support is an enhancement; the pages work without it.
+    });
+  });
+}

vite.config.ts

@@ -2,6 +2,7 @@ import { defineConfig } from "vite";
 import { resolve } from "node:path";
 import { readFileSync } from "node:fs";
 
+import { pwa } from "./build/pwa-vite-plugin";
 import { sites } from "./build/sites-vite-plugin";
 
 const packageVersion = JSON.parse(
@@ -10,7 +11,7 @@ const packageVersion = JSON.parse(
 const buildChannel = process.env.OPENMOUSE_BUILD_CHANNEL ?? "insiders";
 
 export default defineConfig({
-  plugins: [sites()],
+  plugins: [sites(), pwa(packageVersion.version)],
   define: {
     __APP_VERSION__: JSON.stringify(packageVersion.version),
     __BUILD_CHANNEL__: JSON.stringify(buildChannel),