Merge pull request #3629 from pipecat-ai/fix/telephony-websocket-stopasynciteration

Fix StopAsyncIteration in parse_telephony_websocket

src/pipecat/runner/utils.py

@@ -96,6 +96,9 @@ def _detect_transport_type_from_message(message_data: dict) -> str:
 async def parse_telephony_websocket(websocket: WebSocket):
     """Parse telephony WebSocket messages and return transport type and call data.
 
+    Args:
+        websocket: FastAPI WebSocket connection from telephony provider.
+
     Returns:
         tuple: (transport_type: str, call_data: dict)
 
@@ -136,6 +139,9 @@ async def parse_telephony_websocket(websocket: WebSocket):
                 "to": str,
             }
 
+    Raises:
+        ValueError: If WebSocket closes before sending any messages.
+
     Example usage::
 
         transport_type, call_data = await parse_telephony_websocket(websocket)
@@ -143,25 +149,31 @@ async def parse_telephony_websocket(websocket: WebSocket):
             user_id = call_data["body"]["user_id"]
     """
     # Read first two messages
-    start_data = websocket.iter_text()
+    message_stream = websocket.iter_text()
+    first_message = {}
+    second_message = {}
 
     try:
-        # First message
-        first_message_raw = await start_data.__anext__()
+        # First message - required
+        first_message_raw = await message_stream.__anext__()
         logger.trace(f"First message: {first_message_raw}")
-        try:
-            first_message = json.loads(first_message_raw)
-        except json.JSONDecodeError:
-            first_message = {}
+        first_message = json.loads(first_message_raw) if first_message_raw else {}
+    except json.JSONDecodeError:
+        pass
+    except StopAsyncIteration:
+        raise ValueError("WebSocket closed before receiving telephony handshake messages")
 
-        # Second message
-        second_message_raw = await start_data.__anext__()
+    try:
+        # Second message - optional, some providers may only send one
+        second_message_raw = await message_stream.__anext__()
         logger.trace(f"Second message: {second_message_raw}")
-        try:
-            second_message = json.loads(second_message_raw)
-        except json.JSONDecodeError:
-            second_message = {}
+        second_message = json.loads(second_message_raw) if second_message_raw else {}
+    except json.JSONDecodeError:
+        pass
+    except StopAsyncIteration:
+        logger.warning("Only received one WebSocket message, expected two")
 
+    try:
         # Try auto-detection on both messages
         detected_type_first = _detect_transport_type_from_message(first_message)
         detected_type_second = _detect_transport_type_from_message(second_message)