fix: add 10s traffic watchdog to recover from half-dead websocket

ClashFX Team · ClashFX Team · commit 1e09248952b0 · 2026-05-26T18:37:38.000+08:00
Starscream 3.1.1 does not auto-ping, and macOS TCP keep-alive only
fires after ~2 hours. A half-dead connection (NAT timeout, mihomo
deadlock, carrier RST without TCP FIN) never raises a disconnect
callback, so the speed indicator silently freezes on the last
received values even with retry logic in place.

Arm a 10s one-shot timer on every traffic message and on every
successful traffic connect; if the timer fires it means no data has
arrived in 10s and we force resetTrafficStreamApi(), which tears
down the zombie socket and reconnects. Cancel the timer when
entering direct-API mode (no websocket in use).
diff --git a/ClashFX/General/ApiRequest.swift b/ClashFX/General/ApiRequest.swift
@@ -70,7 +70,9 @@ class ApiRequest {
     private var loggingWebSocketRetryDelay: TimeInterval = 1
     private var trafficWebSocketRetryTimer: Timer?
     private var loggingWebSocketRetryTimer: Timer?
+    private var trafficWatchdogTimer: Timer?
     private static let maxRetryDelaySeconds: TimeInterval = 64
+    private static let trafficWatchdogTimeoutSeconds: TimeInterval = 10
 
     private var alamoFireManager: Session
 
@@ -516,6 +518,7 @@ extension ApiRequest {
 
     private func requestTrafficInfo() {
         if ApiRequest.useDirectApi() {
+            cancelTrafficWatchdog()
             trafficWebSocket?.disconnect(forceTimeout: 0.5)
             return
         }
@@ -559,6 +562,7 @@ extension ApiRequest: WebSocketDelegate {
         guard let webSocket = socket as? WebSocket else { return }
         if webSocket == trafficWebSocket {
             trafficWebSocketRetryDelay = 1
+            armTrafficWatchdog()
             Logger.log("trafficWebSocket did Connect", level: .debug)
         } else {
             loggingWebSocketRetryDelay = 1
@@ -607,10 +611,41 @@ extension ApiRequest: WebSocketDelegate {
         loggingWebSocketRetryDelay = min(loggingWebSocketRetryDelay * 2, Self.maxRetryDelaySeconds)
     }
 
+    private func armTrafficWatchdog() {
+        let arm: () -> Void = { [weak self] in
+            guard let self = self else { return }
+            self.trafficWatchdogTimer?.invalidate()
+            self.trafficWatchdogTimer = Timer.scheduledTimer(
+                withTimeInterval: Self.trafficWatchdogTimeoutSeconds, repeats: false
+            ) { [weak self] _ in
+                Logger.log("trafficWebSocket watchdog: no data for \(Self.trafficWatchdogTimeoutSeconds)s, forcing reset", level: .warning)
+                self?.resetTrafficStreamApi()
+            }
+        }
+        if Thread.isMainThread {
+            arm()
+        } else {
+            DispatchQueue.main.async(execute: arm)
+        }
+    }
+
+    private func cancelTrafficWatchdog() {
+        let cancel: () -> Void = { [weak self] in
+            self?.trafficWatchdogTimer?.invalidate()
+            self?.trafficWatchdogTimer = nil
+        }
+        if Thread.isMainThread {
+            cancel()
+        } else {
+            DispatchQueue.main.async(execute: cancel)
+        }
+    }
+
     func websocketDidReceiveMessage(socket: WebSocketClient, text: String) {
         guard let webSocket = socket as? WebSocket else { return }
         let json = JSON(parseJSON: text)
         if webSocket == trafficWebSocket {
+            armTrafficWatchdog()
             delegate?.didUpdateTraffic(up: json["up"].intValue, down: json["down"].intValue)
         } else {
             delegate?.didGetLog(log: json["payload"].stringValue, level: json["type"].string ?? "info")
