fix: implement keep-alive check for Firefox alarms for #8

KarimAziev · Aug 21, 2024 · fbbc73d · fbbc73d
1 parent 8df6423
commit fbbc73d
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Showing 3 changed files with 23 additions and 59 deletions.
diff --git a/firefox/manifest.json b/firefox/manifest.json
@@ -50,7 +50,8 @@
     "activeTab",
     "scripting",
     "storage",
-    "tabs"
+    "tabs",
+    "alarms"
   ],
   "host_permissions": [
     "http://*/*",

diff --git a/src/content-script-tools/text-syncer.ts b/src/content-script-tools/text-syncer.ts
@@ -17,51 +17,7 @@ const errorMessageByCode: {
   1006: `Failed to connect to server: <i>${WS_URL}</i>`,
 };
 
-// 5 seconds
-const KEEP_ALIVE_INTERVAL = 5000;
-
-const currentBrowser = process.env.BROWSER_TARGET;
-const shouldStartKeepAlive = currentBrowser === 'firefox';
-
 class TextSyncer {
-  private keepAliveIntervalId: NodeJS.Timeout | null = null;
-  /**
-   * Starts the keep-alive procedure to maintain communication with the background script.
-   *
-   * This mechanism is specifically implemented because Firefox may terminate the service worker
-   * and close the WebSocket connection if no events occur for 30 seconds, thereby disconnecting you.
-   *
-   * This mess is needed in Firefox due to their lack of support for keeping service workers alive with
-   * WebSocket activity alone (unlike Chrome from version 116 onward).
-   *
-   * @param port The Chrome Extension's port for background communication.
-   */
-  private startKeepAliveLoop(port: chrome.runtime.Port): void {
-    if (this.keepAliveIntervalId) {
-      clearTimeout(this.keepAliveIntervalId);
-    }
-
-    this.keepAliveIntervalId = setTimeout(() => {
-      try {
-        this.post(port, 'keepalive');
-        this.startKeepAliveLoop(port);
-      } catch (error) {
-        console.error('Failed to send keepalive message:', error);
-        this.stopKeepAlive();
-      }
-    }, KEEP_ALIVE_INTERVAL);
-  }
-
-  /**
-   * Stops the keep-alive procedure, ensuring that no further keep-alive messages are sent.
-   */
-  private stopKeepAlive(): void {
-    if (this.keepAliveIntervalId) {
-      clearInterval(this.keepAliveIntervalId);
-      this.keepAliveIntervalId = null;
-    }
-  }
-
   /**
    * Establishes a connection between the content script and background script,
    * and sets up listeners for text updates and disconnect events.
@@ -80,17 +36,10 @@ class TextSyncer {
 
     this.register(port, url, title, handler, options);
 
-    port.onMessage.addListener(this.makeMessageListener(handler, port));
-
+    port.onMessage.addListener(this.makeMessageListener(handler));
     const textChangeListener = this.makeTextChangeListener(port, handler);
-
-    if (shouldStartKeepAlive) {
-      this.startKeepAliveLoop(port);
-    }
-
     handler.bindChange(textChangeListener, false);
     port.onDisconnect.addListener(() => {
-      this.stopKeepAlive();
       handler.unbindChange(textChangeListener, false);
     });
   }
@@ -101,12 +50,8 @@ class TextSyncer {
    * @param handler - The handler instance managing the text element.
    * @returns A function to be used as the onMessage event listener.
    */
-  private makeMessageListener(handler: IHandler, port: chrome.runtime.Port) {
+  private makeMessageListener(handler: IHandler) {
     return (msg: MessageEventData) => {
-      if (shouldStartKeepAlive) {
-        this.startKeepAliveLoop(port);
-      }
-
       if (this[msg.type]) {
         return this[msg.type](handler, msg.payload);
       }
@@ -209,7 +154,7 @@ class TextSyncer {
   private post<T extends keyof SocketPostPayloadMap>(
     port: chrome.runtime.Port,
     type: T,
-    payload?: SocketPostPayloadMap[T],
+    payload: SocketPostPayloadMap[T],
   ) {
     return port.postMessage({ type, payload });
   }

diff --git a/src/service-worker.ts b/src/service-worker.ts
@@ -1,5 +1,23 @@
 import { wsBridge } from '@/background-tools';
 
+const currentBrowser = process.env.BROWSER_TARGET;
+const isFirefox = currentBrowser === 'firefox';
+
+if (isFirefox) {
+  chrome.alarms.create('keepAliveAlarm', { periodInMinutes: 0.1 });
+
+  chrome.alarms.onAlarm.addListener((alarm) => {
+    if (alarm.name === 'keepAliveAlarm') {
+      // Perform a lightweight task to keep the service worker alive
+      chrome.runtime.getPlatformInfo((info) => {
+        console.log(
+          `Alarm triggered: keeping service worker alive. Platform info: ${info.os}`,
+        );
+      });
+    }
+  });
+}
+
 /**
  * Adds an event listener to the Chrome extension's action button (e.g., toolbar icon).
  * On click, it injects the 'content-script.js' into the current tab.