fix: Fix IntegrityId and response parsing for Browse.

s7/_s7commplus_async_client.py

@@ -488,7 +488,8 @@ async def read_symbolic(self, access_area: int, lids: list[int], symbol_crc: int
 
         .. warning:: This method is **experimental** and may change.
         """
-        payload = _build_symbolic_read_payload(access_area, lids, symbol_crc)
+        # TODO: Send the correct integrity id once available
+        payload = _build_symbolic_read_payload(access_area, lids, symbol_crc, False, self._integrity_id_read)
         response = await self._send_request(FunctionCode.GET_MULTI_VARIABLES, payload)
         results = _parse_read_response(response)
         if not results or results[0] is None:
@@ -815,20 +816,20 @@ async def _create_session(self) -> None:
         version, data_length, consumed = decode_header(response_data)
         response = response_data[consumed : consumed + data_length]
 
-        if len(response) < 14:
+        if len(response) < 10:
             raise RuntimeError("CreateObject response too short")
 
-        # Parse response body: ReturnValue(VLQ) + ObjectIdCount + ObjectIds(VLQ).
-        # The usable session id is ObjectIds[0] (NOT the header SessionId field).
-        body = response[14:]
+        # Response header is 10 bytes (opcode+reserved+func+reserved+seq+transport).
+        # Responses do NOT carry a SessionId field (unlike requests which are 14 bytes).
+        body = response[10:]
         object_ids, obj_end = parse_create_object_session_id(body)
         if object_ids:
             self._session_id = object_ids[0]
         else:
             self._session_id = struct.unpack_from(">I", response, 9)[0]
         self._protocol_version = version
 
-        self._server_session_version = parse_server_session_version(response[14 + obj_end :])
+        self._server_session_version = parse_server_session_version(response[10 + obj_end :])
         if self._server_session_version is not None:
             logger.info(f"ServerSessionVersion captured: {len(self._server_session_version)} bytes")
         else:

s7/_s7commplus_client.py

@@ -238,7 +238,8 @@ def read_symbolic(self, access_area: int, lids: list[int], symbol_crc: int = 0)
         if self._connection is None:
             raise RuntimeError("Not connected")
 
-        payload = _build_symbolic_read_payload(access_area, lids, symbol_crc)
+        # TODO: Send the correct integrity id once available
+        payload = _build_symbolic_read_payload(access_area, lids, symbol_crc, False)
         response = self._connection.send_request(FunctionCode.GET_MULTI_VARIABLES, payload)
         results = _parse_read_response(response)
         if not results or results[0] is None:
@@ -730,7 +731,13 @@ def _build_area_write_payload(area_rid: int, start: int, data: bytes) -> bytes:
     return bytes(payload)
 
 
-def _build_symbolic_read_payload(access_area: int, lids: list[int], symbol_crc: int = 0) -> bytes:
+def _build_symbolic_read_payload(
+    access_area: int,
+    lids: list[int],
+    symbol_crc: int = 0,
+    with_integrity: bool = True,
+    integrity_id: int = 1,
+) -> bytes:
     """Build a GetMultiVariables payload for symbolic (LID-based) access.
 
     Used for optimized block access on S7-1200/1500 where byte offsets
@@ -758,7 +765,8 @@ def _build_symbolic_read_payload(access_area: int, lids: list[int], symbol_crc:
     payload += encode_uint32_vlq(field_count)
     payload += addr_bytes
     payload += encode_object_qualifier()
-    payload += encode_uint32_vlq(1)
+    if with_integrity:
+        payload += encode_uint32_vlq(integrity_id)
     payload += struct.pack(">I", 0)
     return bytes(payload)
 

s7/connection.py

@@ -660,7 +660,7 @@ def _init_ssl(self) -> None:
         version, data_length, consumed = decode_header(response_frame)
         response = response_frame[consumed:]
 
-        if len(response) < 14:
+        if len(response) < 10:
             from snap7.error import S7ConnectionError
 
             raise S7ConnectionError("InitSSL response too short")
@@ -751,14 +751,15 @@ def _create_session(self) -> None:
         logger.debug(f"CreateObject response: version=V{version}, data_length={data_length}")
         logger.debug(f"CreateObject response body ({len(response)} bytes): {response.hex(' ')}")
 
-        if len(response) < 14:
+        if len(response) < 10:
             from snap7.error import S7ConnectionError
 
             raise S7ConnectionError("CreateObject response too short")
 
-        # Parse response body: ReturnValue(UInt64 VLQ) + ObjectIdCount + ObjectIds(VLQ).
-        # The usable session id is ObjectIds[0] (NOT the header SessionId field).
-        body = response[14:]
+        # Response header is 10 bytes (opcode+reserved+func+reserved+seq+transport).
+        # Responses do NOT carry a SessionId field (unlike requests which are 14 bytes).
+        # The session ID comes from the payload body, not the header.
+        body = response[10:]
         object_ids, obj_end = parse_create_object_session_id(body)
         if object_ids:
             self._session_id = object_ids[0]
@@ -770,16 +771,16 @@ def _create_session(self) -> None:
         resp_opcode = response[0]
         resp_func = struct.unpack_from(">H", response, 3)[0]
         resp_seq = struct.unpack_from(">H", response, 7)[0]
-        resp_transport = response[13]
+        resp_transport = response[9]
         logger.debug(
             f"CreateObject response header: opcode=0x{resp_opcode:02X} function=0x{resp_func:04X} "
             f"seq={resp_seq} session=0x{self._session_id:08X} transport=0x{resp_transport:02X}"
         )
-        logger.debug(f"CreateObject response payload: {response[14:].hex(' ')}")
+        logger.debug(f"CreateObject response payload: {response[10:].hex(' ')}")
         logger.debug(f"Session created: id=0x{self._session_id:08X} ({self._session_id}), version=V{version}")
 
         # Parse response payload to extract ServerSessionVersion
-        self._server_session_version = parse_server_session_version(response[14 + obj_end :])
+        self._server_session_version = parse_server_session_version(response[10 + obj_end :])
         if self._server_session_version is not None:
             logger.info(f"ServerSessionVersion captured: {len(self._server_session_version)} bytes")
         else: