Fix decoders.decode()

examples/custom_msg.py

@@ -41,7 +41,7 @@ class CustomModbusResponse(ModbusPDU):
     function_code = 55
 
     @classmethod
-    def calculateRtuFrameSize(cls, data: bytes) -> int:
+    def x_calculateRtuFrameSize(cls, data: bytes) -> int:
         """Calculate the size of a PDU."""
         return int(data[2]) + 2 + 3
 
@@ -77,7 +77,7 @@ class CustomRequest(ModbusPDU):
     function_code = 55
 
     @classmethod
-    def calculateRtuFrameSize(cls, data: bytes) -> int:
+    def x_calculateRtuFrameSize(cls, data: bytes) -> int:
         """Calculate the size of a PDU."""
         return 8
 
@@ -145,10 +145,10 @@ async def main(host="localhost", port=5020):
         await client.connect()
 
         # add new modbus function code.
-        assert CustomModbusResponse.calculateRtuFrameSize(b"\x00\x00\x07\x00") == 12
+        assert CustomModbusResponse.x_calculateRtuFrameSize(b"\x00\x00\x07\x00") == 12
         client.register(CustomModbusResponse)
         device_id = 1
-        assert CustomRequest.calculateRtuFrameSize(b"") == 8
+        assert CustomRequest.x_calculateRtuFrameSize(b"") == 8
         request1 = CustomRequest(32, device_id=device_id)
         try:
             result = await client.execute(False, request1)

pymodbus/framer/base.py

@@ -89,7 +89,7 @@ def handleFrame(
                 )
                 continue
             try:
-                pdu, _pdu_size = self.decoder.decode(frame_data)
+                pdu = self.decoder.decode(frame_data)
             except ModbusIOException as exc:
                 exc.transaction_id = tid
                 exc.dev_id = dev_id

pymodbus/framer/rtu.py

@@ -83,11 +83,8 @@ def decode(self, data: bytes) -> tuple[int, int, int, bytes]:
                 Log.debug("Short frame: {} wait for more data", data, ":hex")
                 return 0, 0, 0, self.EMPTY
             dev_id = int(data[used_len])
-            if not (pdu_class := self.decoder.lookupPduClass(data[used_len:])):
+            if not (size := self.decoder.calculateRtuFrameSize(data[used_len:])):
                 continue
-            if not (size := pdu_class.calculateRtuFrameSize(data[used_len:])):
-                Log.debug("Frame - byte_count_pos wrong")
-                return 0, dev_id, 0, self.EMPTY
             if data_len < used_len + size:
                 Log.debug("Frame - not ready")
                 return 0, dev_id, 0, self.EMPTY

pymodbus/pdu/bit_message.py

@@ -19,7 +19,7 @@ class ReadCoilsRequest(ModbusPDU):
     MAX_COUNT = 2000
 
     @classmethod
-    def calculateRtuFrameSize(cls, data: bytes) -> int:
+    def x_calculateRtuFrameSize(cls, data: bytes) -> int:
         """Calculate the size of a PDU."""
         return 8
 
@@ -65,7 +65,7 @@ class ReadCoilsResponse(ModbusPDU):
     function_code = 1
 
     @classmethod
-    def calculateRtuFrameSize(cls, data: bytes) -> int:
+    def x_calculateRtuFrameSize(cls, data: bytes) -> int:
         """Calculate the size of a PDU."""
         return int(data[2]) + 2 + 3
 
@@ -91,7 +91,7 @@ class WriteSingleCoilResponse(ModbusPDU):
     function_code = 5
 
     @classmethod
-    def calculateRtuFrameSize(cls, data: bytes) -> int:
+    def x_calculateRtuFrameSize(cls, data: bytes) -> int:
         """Calculate the size of a PDU."""
         return 8
 
@@ -141,7 +141,7 @@ class WriteMultipleCoilsRequest(ModbusPDU):
     MAX_COUNT = 2000
 
     @classmethod
-    def calculateRtuFrameSize(cls, data: bytes) -> int:
+    def x_calculateRtuFrameSize(cls, data: bytes) -> int:
         """Calculate the size of a PDU."""
         return int(data[6]) + 6 + 3
 
@@ -215,7 +215,7 @@ class WriteMultipleCoilsResponse(ModbusPDU):
     function_code = 15
 
     @classmethod
-    def calculateRtuFrameSize(cls, data: bytes) -> int:
+    def x_calculateRtuFrameSize(cls, data: bytes) -> int:
         """Calculate the size of a PDU."""
         return 8
 

pymodbus/pdu/decoders.py

@@ -21,7 +21,7 @@ def __init__(self, is_server: bool) -> None:
         """Initialize function_tables."""
         self.pdu_inx = 0 if is_server else 1
 
-    def lookupPduClass(self, data: bytes) -> type[ModbusPDU] | None:
+    def _lookupPduClass(self, data: bytes) -> type[ModbusPDU] | None:
         """Use `function_code` to determine the class of the PDU."""
         if (func_code := int(data[1])) & 0x80:
             return ExceptionResponse
@@ -60,29 +60,34 @@ def register(self, custom_class: type[ModbusPDU]) -> None:
             self.pdu_table = copy.deepcopy(DecodePDU.pdu_table)
         self.pdu_table[custom_class.function_code] = (custom_class, custom_class)
 
-    def decode(self, frame: bytes) -> tuple[ModbusPDU, int]:
+    def decode(self, frame: bytes) -> ModbusPDU:
         """Decode a frame."""
         function_code = 0
         try:
             if (function_code := int(frame[0])) > 0x80:
                 pdu_exp = ExceptionResponse(function_code & 0x7F)
                 pdu_exp.x_decode(frame[1:])
-                return pdu_exp, ExceptionResponse.calculateRtuFrameSize(frame)
-            if not (pdu_class := self.lookupPduClass(b"\x00" + frame)):
+                return pdu_exp
+            if not (pdu_class := self._lookupPduClass(b"\x00" + frame)):
                 raise ModbusIOException(
                     f"Unknown response {function_code}", function_code=function_code
                 )
             pdu = pdu_class()
-            pdu_size = pdu.calculateRtuFrameSize(frame)
             pdu.x_decode(frame[1:])
             Log.debug(
                 "decoded PDU function_code({} sub {}) -> {} ",
                 pdu.function_code,
                 pdu.sub_function_code,
                 str(pdu),
             )
-            return pdu, pdu_size
+            return pdu
         except (ValueError, IndexError, struct.error) as exc:
             raise ModbusIOException(
                 f"Unable to decode frame {exc}", function_code=function_code
             ) from exc
+
+    def calculateRtuFrameSize(self, data: bytes) -> int:
+        """Calculate the size of a PDU."""
+        if not (pdu_class := self._lookupPduClass(data)):
+            return 0
+        return pdu_class.x_calculateRtuFrameSize(data)

pymodbus/pdu/diag_message.py

@@ -23,7 +23,7 @@ class DiagnosticBase(ModbusPDU):
     sub_function_code: int = 9999
 
     @classmethod
-    def calculateRtuFrameSize(cls, data: bytes) -> int:
+    def x_calculateRtuFrameSize(cls, data: bytes) -> int:
         """Calculate the size of a PDU."""
         return 8
 
@@ -464,7 +464,7 @@ class GetClearModbusPlusResponse(DiagnosticBase):
     sub_function_code = 0x0015
 
     @classmethod
-    def calculateRtuFrameSize(cls, data: bytes) -> int:
+    def x_calculateRtuFrameSize(cls, data: bytes) -> int:
         """Calculate the size of the message.
 
         Func_code (1 byte) + Sub function code (2 byte) + Operation (2 byte) + Data (108 bytes)

pymodbus/pdu/exceptionresponse.py

@@ -11,7 +11,7 @@ class ExceptionResponse(ModbusPDU):
     """Base class for a modbus exception PDU."""
 
     @classmethod
-    def calculateRtuFrameSize(cls, data: bytes) -> int:
+    def x_calculateRtuFrameSize(cls, data: bytes) -> int:
         """Calculate the size of a PDU."""
         return 5
 

pymodbus/pdu/file_message.py

@@ -37,7 +37,7 @@ class ReadFileRecordRequest(ModbusPDU):
     function_code = 0x14
 
     @classmethod
-    def calculateRtuFrameSize(cls, data: bytes) -> int:
+    def x_calculateRtuFrameSize(cls, data: bytes) -> int:
         """Calculate the size of a PDU."""
         return int(data[2]) + 2 + 3
 
@@ -97,7 +97,7 @@ class ReadFileRecordResponse(ModbusPDU):
     function_code = 0x14
 
     @classmethod
-    def calculateRtuFrameSize(cls, data: bytes) -> int:
+    def x_calculateRtuFrameSize(cls, data: bytes) -> int:
         """Calculate the size of a PDU."""
         return int(data[2]) + 2 + 3
 
@@ -143,7 +143,7 @@ class WriteFileRecordRequest(ModbusPDU):
     function_code = 0x15
 
     @classmethod
-    def calculateRtuFrameSize(cls, data: bytes) -> int:
+    def x_calculateRtuFrameSize(cls, data: bytes) -> int:
         """Calculate the size of a PDU."""
         return int(data[2]) + 2 + 3
 
@@ -207,7 +207,7 @@ class WriteFileRecordResponse(ModbusPDU):
     function_code = 0x15
 
     @classmethod
-    def calculateRtuFrameSize(cls, data: bytes) -> int:
+    def x_calculateRtuFrameSize(cls, data: bytes) -> int:
         """Calculate the size of a PDU."""
         return int(data[2]) + 2 + 3
 
@@ -260,7 +260,7 @@ class ReadFifoQueueRequest(ModbusPDU):
     function_code = 0x18
 
     @classmethod
-    def calculateRtuFrameSize(cls, data: bytes) -> int:
+    def x_calculateRtuFrameSize(cls, data: bytes) -> int:
         """Calculate the size of a PDU."""
         return 6
 
@@ -297,7 +297,7 @@ class ReadFifoQueueResponse(ModbusPDU):
     function_code = 0x18
 
     @classmethod
-    def calculateRtuFrameSize(cls, data: bytes) -> int:
+    def x_calculateRtuFrameSize(cls, data: bytes) -> int:
         """Calculate the size of the message."""
         hi_byte = int(data[2])
         lo_byte = int(data[3])

pymodbus/pdu/mei_message.py

@@ -49,7 +49,7 @@ class ReadDeviceInformationRequest(ModbusPDU):
     sub_function_code = 0x0E
 
     @classmethod
-    def calculateRtuFrameSize(cls, data: bytes) -> int:
+    def x_calculateRtuFrameSize(cls, data: bytes) -> int:
         """Calculate the size of a PDU."""
         return 7
 
@@ -113,7 +113,7 @@ class ReadDeviceInformationResponse(ModbusPDU):
     sub_function_code = 0x0E
 
     @classmethod
-    def calculateRtuFrameSize(cls, data: bytes) -> int:
+    def x_calculateRtuFrameSize(cls, data: bytes) -> int:
         """Calculate the size of the message."""
         size = 8  # skip the header information
         if (data_len := len(data)) < size:

pymodbus/pdu/other_message.py

@@ -21,7 +21,7 @@ class ReadExceptionStatusRequest(ModbusPDU):
     function_code = 0x07
 
     @classmethod
-    def calculateRtuFrameSize(cls, data: bytes) -> int:
+    def x_calculateRtuFrameSize(cls, data: bytes) -> int:
         """Calculate the size of a PDU."""
         return 4
 
@@ -49,7 +49,7 @@ class ReadExceptionStatusResponse(ModbusPDU):
     function_code = 0x07
 
     @classmethod
-    def calculateRtuFrameSize(cls, data: bytes) -> int:
+    def x_calculateRtuFrameSize(cls, data: bytes) -> int:
         """Calculate the size of a PDU."""
         return 5
 
@@ -72,7 +72,7 @@ class GetCommEventCounterRequest(ModbusPDU):
     function_code = 0x0B
 
     @classmethod
-    def calculateRtuFrameSize(cls, data: bytes) -> int:
+    def x_calculateRtuFrameSize(cls, data: bytes) -> int:
         """Calculate the size of a PDU."""
         return 4
 
@@ -100,7 +100,7 @@ class GetCommEventCounterResponse(ModbusPDU):
     function_code = 0x0B
 
     @classmethod
-    def calculateRtuFrameSize(cls, data: bytes) -> int:
+    def x_calculateRtuFrameSize(cls, data: bytes) -> int:
         """Calculate the size of a PDU."""
         return 8
 
@@ -121,7 +121,7 @@ class GetCommEventLogRequest(ModbusPDU):
     function_code = 0x0C
 
     @classmethod
-    def calculateRtuFrameSize(cls, data: bytes) -> int:
+    def x_calculateRtuFrameSize(cls, data: bytes) -> int:
         """Calculate the size of a PDU."""
         return 4
 
@@ -153,7 +153,7 @@ class GetCommEventLogResponse(ModbusPDU):
     function_code = 0x0C
 
     @classmethod
-    def calculateRtuFrameSize(cls, data: bytes) -> int:
+    def x_calculateRtuFrameSize(cls, data: bytes) -> int:
         """Calculate the size of a PDU."""
         return int(data[2]) + 2 + 3
 
@@ -203,7 +203,7 @@ class ReportDeviceIdRequest(ModbusPDU):
     function_code = 0x11
 
     @classmethod
-    def calculateRtuFrameSize(cls, data: bytes) -> int:
+    def x_calculateRtuFrameSize(cls, data: bytes) -> int:
         """Calculate the size of a PDU."""
         return 4
 
@@ -244,7 +244,7 @@ class ReportDeviceIdResponse(ModbusPDU):
     function_code = 0x11
 
     @classmethod
-    def calculateRtuFrameSize(cls, data: bytes) -> int:
+    def x_calculateRtuFrameSize(cls, data: bytes) -> int:
         """Calculate the size of a PDU."""
         return int(data[2]) + 2 + 3
 

pymodbus/pdu/pdu.py

@@ -103,8 +103,8 @@ async def datastore_update(
         )
 
     @classmethod
-    def calculateRtuFrameSize(cls, data: bytes) -> int:
+    def x_calculateRtuFrameSize(cls, data: bytes) -> int:
         """Calculate the size of a PDU."""
         raise NotImplementedException(
-            f"calculateRtuFrameSize() not implemented {cls.__class__.__name__}"
+            f"x_calculateRtuFrameSize() not implemented {cls.__class__.__name__}"
         )