feat(client): Heartbeat ping/pong + auto-reconnect with position restore (#1535)

app.js

@@ -69,6 +69,39 @@ function escHtml(s) {
 let hermesWs = null;
 let wsReconnectTimer = null;
 let wsConnected = false;
+let _heartbeatTimer = null;
+let _heartbeatMissed = 0;
+let _savedPlayerPos = null;
+let _savedPlayerRot = null;
+const HEARTBEAT_INTERVAL = 30000; // 30s
+const HEARTBEAT_MAX_MISSED = 2;
+
+function _startHeartbeat() {
+  _stopHeartbeat();
+  _heartbeatMissed = 0;
+  _heartbeatTimer = setInterval(() => {
+    if (!hermesWs || hermesWs.readyState !== WebSocket.OPEN) return;
+    if (_heartbeatMissed >= HEARTBEAT_MAX_MISSED) {
+      console.warn('Heartbeat: ' + _heartbeatMissed + ' missed pongs. Reconnecting...');
+      hermesWs.close();
+      return;
+    }
+    _heartbeatMissed++;
+    try {
+      hermesWs.send(JSON.stringify({ type: 'ping' }));
+    } catch (e) {
+      console.warn('Heartbeat send failed:', e);
+    }
+  }, HEARTBEAT_INTERVAL);
+}
+
+function _stopHeartbeat() {
+  if (_heartbeatTimer) {
+    clearInterval(_heartbeatTimer);
+    _heartbeatTimer = null;
+  }
+  _heartbeatMissed = 0;
+}
 // ═══ EVENNIA ROOM STATE ═══
 let evenniaRoom = null;   // {title, desc, exits[], objects[], occupants[], timestamp, roomKey}
 let evenniaConnected = false;
@@ -2213,6 +2246,18 @@ function connectHermes() {
     } catch (e) {
       console.warn('[Mnemosyne] Failed to send sync_request:', e);
     }
+
+    // Heartbeat: start ping timer
+    _startHeartbeat();
+
+    // Restore position after reconnect
+    if (_savedPlayerPos && typeof playerPos !== 'undefined') {
+      playerPos = _savedPlayerPos;
+      if (_savedPlayerRot && typeof playerRot !== 'undefined') playerRot = _savedPlayerRot;
+      console.log('Restored player position after reconnect.');
+      _savedPlayerPos = null;
+      _savedPlayerRot = null;
+    }
   };
   
   // Initialize MemPalace
@@ -2221,6 +2266,16 @@ function connectHermes() {
   hermesWs.onmessage = (evt) => {
     try {
       const data = JSON.parse(evt.data);
+
+      // Heartbeat pong: reset missed count
+      if (data.type === 'pong') {
+        _heartbeatMissed = 0;
+        if (data.user_count !== undefined) {
+          console.debug('Heartbeat pong: ' + data.user_count + ' users connected.');
+        }
+        return;
+      }
+
       handleHermesMessage(data);
       
       // Store in MemPalace
@@ -2238,6 +2293,10 @@ function connectHermes() {
   hermesWs.onclose = () => {
     console.warn('Hermes disconnected. Retrying in 5s...');
     wsConnected = false;
+    _stopHeartbeat();
+    // Save position for reconnect
+    if (typeof playerPos !== 'undefined') _savedPlayerPos = playerPos;
+    if (typeof playerRot !== 'undefined') _savedPlayerRot = playerRot;
     hermesWs = null;
     updateWsHudStatus(false);
     refreshWorkshopPanel();

server.py

@@ -44,6 +44,16 @@ async def broadcast_handler(websocket: websockets.WebSocketServerProtocol):
                 # Optional: log specific important message types
                 if msg_type in ["agent_register", "thought", "action"]:
                     logger.debug(f"Received {msg_type} from {addr}")
+
+                # Heartbeat: respond with pong + user count
+                if msg_type == "ping":
+                    pong = json.dumps({
+                        "type": "pong",
+                        "user_count": len(clients),
+                        "timestamp": asyncio.get_event_loop().time()
+                    })
+                    await websocket.send(pong)
+                    continue
             except (json.JSONDecodeError, TypeError):
                 pass