实现 WakeUpPing

src/offscreen.ts

@@ -2,6 +2,7 @@ import LoggerCore from "./app/logger/core";
 import MessageWriter from "./app/logger/message_writer";
 import { OffscreenManager } from "./app/service/offscreen";
 import { ServiceWorkerClientMessage } from "@Packages/message/window_message";
+import { startRepetitivePing } from "./pkg/utils/wakeup-ping";
 
 function main() {
   // 通过postMessage与SW通信,支持结构化克隆(Blob等)
@@ -15,6 +16,7 @@ function main() {
   // 初始化管理器
   const manager = new OffscreenManager(swPostMessage);
   manager.initManager();
+  startRepetitivePing();
 }
 
 main();

src/pkg/utils/wakeup-ping.ts

@@ -0,0 +1,63 @@
+const PING_INTERVAL_MS_1 = 13_225;
+const PING_INTERVAL_MS_2 = 17_765;
+
+/**
+ * scheduler 用于后台排程：Chrome 94+, Firefox 142+
+ * @link https://developer.mozilla.org/en-US/docs/Web/API/Scheduler/postTask
+ */
+const nativeScheduler =
+  //@ts-ignore
+  typeof scheduler !== "undefined" && typeof scheduler?.postTask === "function" && scheduler;
+
+// 高效的 BroadcastChannel 通讯：service worker 和 offscreen 共用同一通道
+const channel = new BroadcastChannel("custom-ping");
+
+export const startRepetitivePing = () => {
+  if (typeof frameElement === "object" && typeof document === "object" && document) {
+    let counter = 0;
+    let isMutationPending = false;
+
+    const pingNode = document.createComment("0");
+
+    const incrementCounter = () => {
+      if (!isMutationPending) {
+        isMutationPending = true;
+        counter = counter > 8 ? 1 : counter + 1;
+        pingNode.data = `${counter}`;
+      }
+    };
+
+    const pingTask = async () => {
+      channel.postMessage({});
+      incrementCounter();
+    };
+
+    const mutationObserver = new MutationObserver(() => {
+      if (isMutationPending) {
+        isMutationPending = false;
+        const pingIntervalMs = Math.random() * (PING_INTERVAL_MS_2 - PING_INTERVAL_MS_1) + PING_INTERVAL_MS_1;
+        if (nativeScheduler) {
+          nativeScheduler.postTask(pingTask, { priority: "background", delay: pingIntervalMs });
+        } else {
+          setTimeout(pingTask, pingIntervalMs);
+        }
+      }
+    });
+    mutationObserver.observe(pingNode, { characterData: true });
+    incrementCounter();
+  }
+};
+
+export const listenWakeupPing = (onWakeupPing: (...args: any) => any) => {
+  chrome.storage.session.onChanged.addListener((obj) => {
+    // 消耗 persistentWakeup
+    if (typeof obj.persistentWakeup !== "undefined") {
+      // 执行任意 callback
+      onWakeupPing();
+    }
+  });
+  channel.onmessage = (e) => {
+    // 触发 chrome storage onChanged 使 service worker 保持活跃
+    chrome.storage.session.set({ persistentWakeup: `${e.timeStamp}` });
+  };
+};

src/service_worker.ts

@@ -8,6 +8,7 @@ import { MessageQueue } from "@Packages/message/message_queue";
 import { ServiceWorkerMessageSend } from "@Packages/message/window_message";
 import migrate, { migrateChromeStorage } from "./app/migrate";
 import { cleanInvalidKeys } from "./app/repo/resource";
+import { listenWakeupPing } from "./pkg/utils/wakeup-ping";
 
 migrate();
 migrateChromeStorage();
@@ -59,6 +60,10 @@ async function setupOffscreenDocument() {
   }
 }
 
+export const onWakeupPing = () => {
+  console.debug("onWakeupPing"); // 不用记录在系统日志
+};
+
 function main() {
   cleanInvalidKeys();
   // 初始化管理器
@@ -77,6 +82,7 @@ function main() {
   manager.initManager();
   // 初始化沙盒环境
   setupOffscreenDocument();
+  listenWakeupPing(onWakeupPing);
 }
 
 main();