.env.example

@@ -26,4 +26,7 @@ MYSQL_POOL_SIZE=5
 MAX_CONCURRENT_SSH=32
 
 # Paramiko SSH keepalive interval (seconds); set 0 to disable.
-SSH_KEEPALIVE_INTERVAL=30
+SSH_KEEPALIVE_INTERVAL=15
+
+# WebSocket keepalive interval (seconds); server sends traffic to avoid proxy idle timeouts.
+WS_KEEPALIVE_INTERVAL=25

app.py

@@ -644,7 +644,26 @@ def _close_ssh_entry(entry: dict[str, Any]) -> None:
 
 
 MAX_CONCURRENT_SSH = int(os.getenv("MAX_CONCURRENT_SSH", "32"))
-SSH_KEEPALIVE_INTERVAL = int(os.getenv("SSH_KEEPALIVE_INTERVAL", "30"))
+SSH_KEEPALIVE_INTERVAL = int(os.getenv("SSH_KEEPALIVE_INTERVAL", "15"))
+WS_KEEPALIVE_INTERVAL = int(os.getenv("WS_KEEPALIVE_INTERVAL", "25"))
+
+
+def _apply_ssh_keepalive(client: paramiko.SSHClient) -> None:
+    if SSH_KEEPALIVE_INTERVAL <= 0:
+        return
+    transport = client.get_transport()
+    if transport is not None:
+        transport.set_keepalive(SSH_KEEPALIVE_INTERVAL)
+
+
+def _ssh_transports_alive(
+    client: paramiko.SSHClient, jump_clients: list[paramiko.SSHClient] | None
+) -> bool:
+    for ssh_client in (client, *(jump_clients or [])):
+        transport = ssh_client.get_transport()
+        if transport is None or not transport.is_active():
+            return False
+    return True
 
 
 class GeventWsAppResponse(Response):
@@ -795,9 +814,7 @@ def _connect_paramiko(host_row: dict, sock=None) -> tuple[paramiko.SSHClient, pa
         )
 
     if SSH_KEEPALIVE_INTERVAL > 0:
-        transport = client.get_transport()
+        _apply_ssh_keepalive(client)
-        if transport is not None:
-            transport.set_keepalive(SSH_KEEPALIVE_INTERVAL)
 
     chan = client.invoke_shell(term="xterm-256color", width=120, height=40)
     chan.setblocking(True)
@@ -1839,8 +1856,8 @@ def ws_terminal():
                         height=int(o.get("rows", 40)),
                     )
                     return True
-                elif o.get("type") == "ping":
+                if o.get("type") == "ping":
-                    # Ping message to keep connection alive, ignore without sending to channel
+                    sock.send(json.dumps({"type": "pong"}))
                     return True
             except (json.JSONDecodeError, TypeError, ValueError):
                 pass
@@ -1889,6 +1906,7 @@ def ws_terminal():
             )
         )
 
+        last_ws_keepalive = time.monotonic()
         while not stop.is_set():
             drained_eof = False
             try:
@@ -1898,16 +1916,31 @@ def ws_terminal():
                         drained_eof = True
                         break
                     sock.send(item)
+                    last_ws_keepalive = time.monotonic()
             except queue.Empty:
                 pass
             if drained_eof:
                 break
 
+            now = time.monotonic()
+            if (
+                WS_KEEPALIVE_INTERVAL > 0
+                and now - last_ws_keepalive >= WS_KEEPALIVE_INTERVAL
+            ):
+                if not _ssh_transports_alive(client, jump_clients):
+                    break
+                try:
+                    sock.send(json.dumps({"type": "keepalive"}))
+                except Exception:
+                    break
+                last_ws_keepalive = now
+
             msg = sock.receive(timeout=0.15)
             if msg is None:
                 if use_gevent_wsgi and getattr(sock, "_gw", None) is not None and sock._gw.closed:
                     break
                 continue
+            last_ws_keepalive = time.monotonic()
             if not handle_ws_inbound(msg):
                 break
     except ConnectionClosed:

frontend/src/components/TabContent.vue

@@ -24,7 +24,7 @@ let ws: WebSocket | null = null;
 let term: Terminal | null = null;
 let fit: FitAddon | null = null;
 let ro: ResizeObserver | null = null;
-let pingInterval: NodeJS.Timeout | null = null;
+let visibilityHandler: (() => void) | null = null;
 
 function wsUrl(hostId: number): string {
   const proto = location.protocol === "https:" ? "wss:" : "ws:";
@@ -37,6 +37,12 @@ function sendResize() {
   ws.send(JSON.stringify({ type: "resize", ...dims }));
 }
 
+function sendPing() {
+  if (ws && ws.readyState === WebSocket.OPEN) {
+    ws.send(JSON.stringify({ type: "ping" }));
+  }
+}
+
 function fitAndResize() {
   if (!fit || !term || !props.visible) return;
   try {
@@ -47,6 +53,25 @@ function fitAndResize() {
   }
 }
 
+function isControlMessage(raw: string): boolean {
+  try {
+    const o = JSON.parse(raw) as { type?: string; conn_id?: string };
+    if (o.type === "ready" && o.conn_id) {
+      connId.value = o.conn_id;
+      status.value = "";
+      fitAndResize();
+      term?.focus();
+      return true;
+    }
+    if (o.type === "keepalive" || o.type === "pong") {
+      return true;
+    }
+  } catch {
+    /* not JSON control traffic */
+  }
+  return false;
+}
+
 onMounted(async () => {
   await nextTick();
   if (!termEl.value) return;
@@ -87,29 +112,12 @@ onMounted(async () => {
   ws.onopen = () => {
     status.value = "Handshaking…";
     sendResize();
-    // Send ping every 60 seconds to keep connection alive
-    pingInterval = setInterval(() => {
-      if (ws && ws.readyState === WebSocket.OPEN) {
-        ws.send(JSON.stringify({ type: "ping" }));
-      }
-    }, 60000);
   };
 
   ws.onmessage = (ev) => {
     if (!term) return;
     if (typeof ev.data === "string") {
-      try {
+      if (isControlMessage(ev.data)) return;
-        const o = JSON.parse(ev.data) as { type?: string; conn_id?: string };
-        if (o.type === "ready" && o.conn_id) {
-          connId.value = o.conn_id;
-          status.value = "";
-          fitAndResize();
-          term.focus();
-          return;
-        }
-      } catch {
-        /* fall through */
-      }
       term.write(ev.data);
       return;
     }
@@ -122,22 +130,26 @@ onMounted(async () => {
   };
 
   ws.onclose = () => {
-    if (pingInterval) {
-      clearInterval(pingInterval);
-      pingInterval = null;
-    }
     if (!connId.value) {
       status.value = "Disconnected";
     } else {
       status.value = "Session ended";
     }
   };
+
+  visibilityHandler = () => {
+    if (document.visibilityState === "visible") {
+      sendPing();
+      fitAndResize();
+    }
+  };
+  document.addEventListener("visibilitychange", visibilityHandler);
 });
 
 onUnmounted(() => {
-  if (pingInterval) {
+  if (visibilityHandler) {
-    clearInterval(pingInterval);
+    document.removeEventListener("visibilitychange", visibilityHandler);
-    pingInterval = null;
+    visibilityHandler = null;
   }
   ro?.disconnect();
   ro = null;
@@ -155,6 +167,7 @@ watch(
       await nextTick();
       fitAndResize();
       term?.focus();
+      sendPing();
     }
   },
 );