[gardena] Fix server ping timeout logic (#14203)

On server timeouts, it's possible for multiple minutes to elapse
between receiving the last pong on the old connection and attempting to
send the next ping on the new connection. If that time span exceeded 5
minutes, the binding went into a minutely reconnection loop, because it
never attempted to send a ping anymore, which led to lastPong not being
updated anymore.
To fix this, replace the timing dependent timestamp handling by a simple
counter which counts how many consecutive ping attempts didn't receive
an answer, and closing the connection after 5 unsuccessful ping
attempts. That new counter is now also reset whenever the connection is
restarted.

Fixes #14188

Signed-off-by: Danny Baumann <dannybaumann@web.de>

diff --git a/bundles/org.openhab.binding.gardena/src/main/java/org/openhab/binding/gardena/internal/GardenaSmartWebSocket.java b/bundles/org.openhab.binding.gardena/src/main/java/org/openhab/binding/gardena/internal/GardenaSmartWebSocket.java
index 0999feda38b821b3da0cc37699b27f0ebd11bccb..9ef2ca5078b06abbd8ba48ed59ff92349c7fd946 100644 (file)
--- a/bundles/org.openhab.binding.gardena/src/main/java/org/openhab/binding/gardena/internal/GardenaSmartWebSocket.java
+++ b/bundles/org.openhab.binding.gardena/src/main/java/org/openhab/binding/gardena/internal/GardenaSmartWebSocket.java
@@ -16,7 +16,6 @@ import java.io.IOException;
 import java.net.URI;
 import java.nio.ByteBuffer;
 import java.nio.charset.StandardCharsets;
-import java.time.Instant;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.TimeUnit;
@@ -49,12 +48,12 @@ import org.slf4j.LoggerFactory;
 public class GardenaSmartWebSocket {
     private final Logger logger = LoggerFactory.getLogger(GardenaSmartWebSocket.class);
     private final GardenaSmartWebSocketListener socketEventListener;
-    private final long WEBSOCKET_IDLE_TIMEOUT = 300;
+    private final int MAX_UNANSWERED_PINGS = 5;
 
     private WebSocketSession session;
     private WebSocketClient webSocketClient;
     private boolean closing;
-    private Instant lastPong = Instant.now();
+    private int unansweredPings = 0;
     private ScheduledExecutorService scheduler;
     private @Nullable ScheduledFuture<?> connectionTracker;
     private ByteBuffer pingPayload = ByteBuffer.wrap("ping".getBytes(StandardCharsets.UTF_8));
@@ -115,8 +114,9 @@ public class GardenaSmartWebSocket {
     }
 
     @OnWebSocketConnect
-    public void onConnect(Session session) {
+    public synchronized void onConnect(Session session) {
         closing = false;
+        unansweredPings = 0;
         logger.debug("Connected to Gardena Webservice ({})", socketId);
 
         ScheduledFuture<?> connectionTracker = this.connectionTracker;
@@ -129,9 +129,9 @@ public class GardenaSmartWebSocket {
     }
 
     @OnWebSocketFrame
-    public void onFrame(Frame pong) {
+    public synchronized void onFrame(Frame pong) {
         if (pong instanceof PongFrame) {
-            lastPong = Instant.now();
+            unansweredPings = 0;
             logger.trace("Pong received ({})", socketId);
         }
     }
@@ -170,14 +170,14 @@ public class GardenaSmartWebSocket {
      */
     private synchronized void sendKeepAlivePing() {
         final PostOAuth2Response accessToken = token;
-        if ((Instant.now().getEpochSecond() - lastPong.getEpochSecond() > WEBSOCKET_IDLE_TIMEOUT) || accessToken == null
-                || accessToken.isAccessTokenExpired()) {
+        if (unansweredPings > MAX_UNANSWERED_PINGS || accessToken == null || accessToken.isAccessTokenExpired()) {
             session.close(1000, "Timeout manually closing dead connection (" + socketId + ")");
         } else {
             if (session.isOpen()) {
                 try {
                     logger.trace("Sending ping ({})", socketId);
                     session.getRemote().sendPing(pingPayload);
+                    ++unansweredPings;
                 } catch (IOException ex) {
                     logger.debug("Error while sending ping: {}", ex.getMessage());
                 }