Offer the display update as soon as the display is behind

README.md

@@ -264,8 +264,9 @@ sudo systemctl restart led-matrix    # after changing config.ini
 
 **Update:** when a newer release is out, the settings page says so and has
 an *Update now* button. The Pi looks for one a minute after it starts and
-then every six hours; it only asks GitHub, nothing is opened towards the
-internet. The button takes about a minute, the panel goes dark briefly, and
+then every six hours, and again while the settings page or the app's *More*
+is open (at most every ten minutes); it only asks GitHub, nothing is opened
+towards the internet. The button takes about a minute, the panel goes dark briefly, and
 the page reloads in the new version. The app connected to the display offers
 the same under *More*, with a dot on the tab while an update is waiting. The
 button looks for the newest release once more before it starts, so it never

app/pet.html

@@ -3217,16 +3217,20 @@ <h2 data-t="page.tabs.more"></h2>
   // (the Pi then installs the newest release up to the app's version, see startUpdate)
   const ahead = u.available && app.aheadOfApp(u.latest);
   const upToApp = ahead && app.belowApp(u.current);
+  // a display older than this app has a release waiting (the app's own), even before the Pi's
+  // next look has found it: the button makes it look right away
+  const behind = !u.available && !u.running && app.belowApp(u.current);
   const lines = [t("page.app.update_version", { version: u.current })];
   if (u.running) lines.push(t("page.app.update_running"));
-  else if (upToApp) lines.push(t("page.app.update_available", { latest: app.version }));
+  else if (upToApp || behind) lines.push(t("page.app.update_available", { latest: app.version }));
   else if (ahead) lines.push(t("page.app.update_app_first", { latest: u.latest }));
   else if (u.available) lines.push(t("page.app.update_available", { latest: u.latest }));
   else if (u.failed) lines.push(t("page.app.update_failed"));
   $("update-text").textContent = lines.join(" ");
   $("update-text").hidden = false;
-  $("update-start").hidden = (ahead && !upToApp) || (!u.available && !(app.fit() === "display_old" && !u.running));
-  document.querySelector('[data-view="more"]').classList.toggle("news", u.available && (!ahead || upToApp));
+  $("update-start").hidden = (ahead && !upToApp)
+    || (!u.available && !behind && !(app.fit() === "display_old" && !u.running));
+  document.querySelector('[data-view="more"]').classList.toggle("news", (u.available && (!ahead || upToApp)) || behind);
 }
 
 // The Pi looks for the newest release once more before it starts, so this never waits for its next

pi/src/update.ts

@@ -68,6 +68,9 @@ export class Updates {
   latest: string | null = null;
   private running = false;
   private failed = false;
+  /** When the last look started (ms), and the look that is under way. */
+  private looked = 0;
+  private looking: Promise<void> | null = null;
 
   /**
    * `directory`: where VERSION and REPO are (the app's folder). `beta`: whether betas are wanted
@@ -97,6 +100,7 @@ export class Updates {
     if (!this.enabled) {
       return;
     }
+    this.looked = Date.now();
     await this.checkUnit();
     try {
       const tag = this.beta() ? await this.newestBeta() : await this.newestRelease();
@@ -109,6 +113,18 @@ export class Updates {
     }
   }
 
+  /**
+   * Looks again in the background when the last look is older than `maxAge` (ms), so somebody
+   * who opens the app or the settings page sees a release from a minute ago on the next answer,
+   * not only after the next regular look hours later. Never more than one look at a time.
+   */
+  lookIfOlder(maxAge: number): void {
+    if (!this.enabled || this.looking || Date.now() - this.looked < maxAge) {
+      return;
+    }
+    this.looking = this.check().finally(() => { this.looking = null; });
+  }
+
   /** The newest release: .../releases/latest redirects to .../releases/tag/<version> (it skips pre-releases). */
   private async newestRelease(): Promise<string> {
     const response = await this.request(`https://github.com/${this.repo}/releases/latest`,

pi/src/web.ts

@@ -23,6 +23,7 @@ const log = getLog("web");
 const MAX_BODY = 64 * 1024; // small JSON requests only
 const MAX_SAVE = 2 * 1024 * 1024; // a save file loaded on the settings page
 const PREVIEW_WAIT = 1; // seconds the preview waits for the next frame at most
+const LOOK_AGAIN = 10 * 60_000; // ms after a look for a new release before GET /api/state looks again
 // background of the pet app, as "#111318"
 
 // ---------- Pages ----------
@@ -176,6 +177,9 @@ export function createApp(options: WebOptions): (request: IncomingMessage, respo
         return html(page(request, "index.html", { languages: settings.languages() }));
 
       case "GET /api/state":
+        // the app and the settings page ask for this while they show the update: a release
+        // published since the last look shows up there within minutes (GitHub allows 60 looks an hour)
+        updates.lookIfOlder(LOOK_AGAIN);
         return json(stateJson());
 
       case "POST /api/mode":

pi/test/update.test.ts

@@ -177,3 +177,23 @@ test("an app asks for an update up to its own version: the newest release up to
   assert.equal(await plain.start("not a version!"), true);
   assert.equal(readFileSync(env, "utf-8"), "LED_MATRIX_VERSION=v1.1.0\n");
 });
+
+test("a look that is old is done again in the background, one at a time", async () => {
+  let asked = 0;
+  const request = (async () => {
+    asked++;
+    return { ok: true, status: 200, url: "https://github.com/someone/blobling/releases/tag/v1.1.0" };
+  }) as unknown as typeof fetch;
+  const updates = new Updates(release("v1.0.0"), request, systemctl("inactive"));
+  updates.lookIfOlder(60_000);
+  updates.lookIfOlder(60_000); // the first one is still under way
+  await new Promise((resolve) => setTimeout(resolve, 10));
+  assert.equal(asked, 1);
+  assert.equal(updates.state().latest, "v1.1.0");
+  updates.lookIfOlder(60_000); // just looked
+  await new Promise((resolve) => setTimeout(resolve, 10));
+  assert.equal(asked, 1);
+  updates.lookIfOlder(0);
+  await new Promise((resolve) => setTimeout(resolve, 10));
+  assert.equal(asked, 2);
+});