integrate message.encode() into framer.buildPacket. (#2062)

Author: janiversen

pymodbus/framer/ascii_framer.py

@@ -41,6 +41,7 @@ def __init__(self, decoder, client=None):
         self._hsize = 0x02
         self._start = b":"
         self._end = b"\r\n"
+        self.message_handler = MessageAscii([0], True)
 
     def decode_data(self, data):
         """Decode data."""
@@ -112,7 +113,12 @@ def buildPacket(self, message):
         packet.extend(b2a_hex(encoded))
         packet.extend(f"{checksum:02x}".encode())
         packet.extend(self._end)
-        return bytes(packet).upper()
+        packet = bytes(packet).upper()
+
+        data = message.function_code.to_bytes(1,'big') + encoded
+        packet_new = self.message_handler.encode(data, message.slave_id, message.transaction_id)
+        assert packet == packet_new, "ASCII FRAMER BuildPacket failed!"
+        return packet
 
 
 # __END__

pymodbus/framer/binary_framer.py

@@ -5,7 +5,7 @@
 from pymodbus.exceptions import ModbusIOException
 from pymodbus.framer.base import BYTE_ORDER, FRAME_HEADER, ModbusFramer
 from pymodbus.logging import Log
-from pymodbus.utilities import checkCRC, computeCRC
+from pymodbus.message.rtu import MessageRTU
 
 
 BINARY_FRAME_HEADER = BYTE_ORDER + FRAME_HEADER
@@ -76,7 +76,7 @@ def check_frame(self) -> bool:
                 self._header["uid"] = struct.unpack(">B", self._buffer[1:2])[0]
                 self._header["crc"] = struct.unpack(">H", self._buffer[end - 2 : end])[0]
                 data = self._buffer[1 : end - 2]
-                return checkCRC(data, self._header["crc"])
+                return MessageRTU.check_CRC(data, self._header["crc"])
             return False
 
         while len(self._buffer) > 1:
@@ -113,7 +113,7 @@ def buildPacket(self, message):
             struct.pack(BINARY_FRAME_HEADER, message.slave_id, message.function_code)
             + data
         )
-        packet += struct.pack(">H", computeCRC(packet))
+        packet += struct.pack(">H", MessageRTU.compute_CRC(packet))
         packet = self._start + packet + self._end
         return packet
 

pymodbus/framer/rtu_framer.py

@@ -8,7 +8,8 @@
 )
 from pymodbus.framer.base import BYTE_ORDER, FRAME_HEADER, ModbusFramer
 from pymodbus.logging import Log
-from pymodbus.utilities import ModbusTransactionState, checkCRC, computeCRC
+from pymodbus.message.rtu import MessageRTU
+from pymodbus.utilities import ModbusTransactionState
 
 
 RTU_FRAME_HEADER = BYTE_ORDER + FRAME_HEADER
@@ -62,6 +63,7 @@ def __init__(self, decoder, client=None):
         self._end = b"\x0d\x0a"
         self._min_frame_size = 4
         self.function_codes = decoder.lookup.keys() if decoder else {}
+        self.message_handler = MessageRTU([0], True)
 
     def decode_data(self, data):
         """Decode data."""
@@ -131,7 +133,7 @@ def check_frame(self):
                 data = self._buffer[: frame_size - 2]
                 crc = self._header["crc"]
                 crc_val = (int(crc[0]) << 8) + int(crc[1])
-                return checkCRC(data, crc_val)
+                return MessageRTU.check_CRC(data, crc_val)
             except (IndexError, KeyError, struct.error):
                 return False
 
@@ -175,7 +177,12 @@ def buildPacket(self, message):
             struct.pack(RTU_FRAME_HEADER, message.slave_id, message.function_code)
             + data
         )
-        packet += struct.pack(">H", computeCRC(packet))
+        packet += struct.pack(">H", MessageRTU.compute_CRC(packet))
+
+        data_new = message.function_code.to_bytes(1, 'big') + data
+        packet_new = self.message_handler.encode(data_new, message.slave_id, message.transaction_id)
+        assert packet == packet_new, "RTU FRAMER BuildPacket failed!"
+
         # Ensure that transaction is actually the slave id for serial comms
         if message.slave_id:
             message.transaction_id = message.slave_id

pymodbus/framer/socket_framer.py

@@ -7,6 +7,7 @@
 )
 from pymodbus.framer.base import SOCKET_FRAME_HEADER, ModbusFramer
 from pymodbus.logging import Log
+from pymodbus.message.socket import MessageSocket
 
 
 # --------------------------------------------------------------------------- #
@@ -42,6 +43,7 @@ def __init__(self, decoder, client=None):
         """
         super().__init__(decoder, client)
         self._hsize = 0x07
+        self.message_handler = MessageSocket([0], True)
 
     def decode_data(self, data):
         """Decode data."""
@@ -126,4 +128,8 @@ def buildPacket(self, message):
             message.function_code,
         )
         packet += data
+
+        data_new = message.function_code.to_bytes(1, 'big') + data
+        packet_new = self.message_handler.encode(data_new, message.slave_id, message.transaction_id)
+        assert packet == packet_new, "SOCKET FRAMER BuildPacket failed!"
         return packet

pymodbus/framer/tls_framer.py

@@ -7,6 +7,7 @@
 )
 from pymodbus.framer.base import TLS_FRAME_HEADER, ModbusFramer
 from pymodbus.logging import Log
+from pymodbus.message.tls import MessageTLS
 
 
 # --------------------------------------------------------------------------- #
@@ -34,6 +35,7 @@ def __init__(self, decoder, client=None):
         """
         super().__init__(decoder, client)
         self._hsize = 0x0
+        self.message_encoder = MessageTLS([0], True)
 
     def decode_data(self, data):
         """Decode data."""
@@ -80,6 +82,10 @@ def buildPacket(self, message):
         data = message.encode()
         packet = struct.pack(TLS_FRAME_HEADER, message.function_code)
         packet += data
+
+        data_new = message.function_code.to_bytes(1,'big') + data
+        packet_new = self.message_encoder.encode(data_new, message.slave_id, message.transaction_id)
+        assert packet == packet_new, "TLS FRAMER BuildPacket failed!"
         return packet
 
 

pymodbus/message/rtu.py

@@ -40,10 +40,62 @@ class MessageRTU(MessageBase):
     neither when receiving nor when sending.
     """
 
+    @classmethod
+    def generate_crc16_table(cls) -> list[int]:
+        """Generate a crc16 lookup table.
+
+        .. note:: This will only be generated once
+        """
+        result = []
+        for byte in range(256):
+            crc = 0x0000
+            for _ in range(8):
+                if (byte ^ crc) & 0x0001:
+                    crc = (crc >> 1) ^ 0xA001
+                else:
+                    crc >>= 1
+                byte >>= 1
+            result.append(crc)
+        return result
+    crc16_table: list[int] = [0]
+
     def decode(self, _data: bytes) -> tuple[int, int, int, bytes]:
         """Decode message."""
         return 0, 0, 0, b''
 
-    def encode(self, _data: bytes, _device_id: int, _tid: int) -> bytes:
+    def encode(self, data: bytes, device_id: int, _tid: int) -> bytes:
         """Decode message."""
-        return b''
+        packet = device_id.to_bytes(1,'big') + data
+        return packet + MessageRTU.compute_CRC(packet).to_bytes(2,'big')
+
+    @classmethod
+    def check_CRC(cls, data: bytes, check: int) -> bool:
+        """Check if the data matches the passed in CRC.
+
+        :param data: The data to create a crc16 of
+        :param check: The CRC to validate
+        :returns: True if matched, False otherwise
+        """
+        return cls.compute_CRC(data) == check
+
+    @classmethod
+    def compute_CRC(cls, data: bytes) -> int:
+        """Compute a crc16 on the passed in bytes.
+
+        For modbus, this is only used on the binary serial protocols (in this
+        case RTU).
+
+        The difference between modbus's crc16 and a normal crc16
+        is that modbus starts the crc value out at 0xffff.
+
+        :param data: The data to create a crc16 of
+        :returns: The calculated CRC
+        """
+        crc = 0xFFFF
+        for data_byte in data:
+            idx = cls.crc16_table[(crc ^ int(data_byte)) & 0xFF]
+            crc = ((crc >> 8) & 0xFF) ^ idx
+        swapped = ((crc << 8) & 0xFF00) | ((crc >> 8) & 0x00FF)
+        return swapped
+
+MessageRTU.crc16_table = MessageRTU.generate_crc16_table()

pymodbus/utilities.py

@@ -10,8 +10,6 @@
     "pack_bitstring",
     "unpack_bitstring",
     "default",
-    "computeCRC",
-    "checkCRC",
     "rtuFrameSize",
 ]
 
@@ -152,57 +150,6 @@ def unpack_bitstring(data: bytes) -> list[bool]:
 # --------------------------------------------------------------------------- #
 
 
-def __generate_crc16_table():
-    """Generate a crc16 lookup table.
-
-    .. note:: This will only be generated once
-    """
-    result = []
-    for byte in range(256):
-        crc = 0x0000
-        for _ in range(8):
-            if (byte ^ crc) & 0x0001:
-                crc = (crc >> 1) ^ 0xA001
-            else:
-                crc >>= 1
-            byte >>= 1
-        result.append(crc)
-    return result
-
-
-__crc16_table = __generate_crc16_table()
-
-
-def computeCRC(data):  # pylint: disable=invalid-name
-    """Compute a crc16 on the passed in string.
-
-    For modbus, this is only used on the binary serial protocols (in this
-    case RTU).
-
-    The difference between modbus's crc16 and a normal crc16
-    is that modbus starts the crc value out at 0xffff.
-
-    :param data: The data to create a crc16 of
-    :returns: The calculated CRC
-    """
-    crc = 0xFFFF
-    for data_byte in data:
-        idx = __crc16_table[(crc ^ int(data_byte)) & 0xFF]
-        crc = ((crc >> 8) & 0xFF) ^ idx
-    swapped = ((crc << 8) & 0xFF00) | ((crc >> 8) & 0x00FF)
-    return swapped
-
-
-def checkCRC(data, check):  # pylint: disable=invalid-name
-    """Check if the data matches the passed in CRC.
-
-    :param data: The data to create a crc16 of
-    :param check: The CRC to validate
-    :returns: True if matched, False otherwise
-    """
-    return computeCRC(data) == check
-
-
 def rtuFrameSize(data, byte_count_pos):  # pylint: disable=invalid-name
     """Calculate the size of the frame based on the byte count.
 

pyproject.toml

@@ -225,7 +225,11 @@ source = [
     "pymodbus/",
     "test/",
 ]
-omit = ["examples/contrib/"]
+omit = [
+    "examples/contrib/",
+    "test/message/to_do*",
+    "test/message/generator.py",
+    ]
 branch = true
 
 [tool.coverage.report]

test/message/generator.py

@@ -0,0 +1,46 @@
+#!/usr/bin/env python3
+"""Build framer encode responses."""
+
+from pymodbus.factory import ClientDecoder, ServerDecoder
+from pymodbus.framer import (
+    ModbusAsciiFramer,
+    ModbusRtuFramer,
+    ModbusSocketFramer,
+    ModbusTlsFramer,
+)
+from pymodbus.pdu import ModbusExceptions as merror
+from pymodbus.register_read_message import (
+    ReadHoldingRegistersRequest,
+    ReadHoldingRegistersResponse,
+)
+
+
+def set_calls():
+    """Define calls."""
+    for framer in (ModbusAsciiFramer, ModbusRtuFramer, ModbusSocketFramer, ModbusTlsFramer):
+        print(f"framer --> {framer}")
+        for dev_id in (0, 17, 255):
+            print(f"  dev_id --> {dev_id}")
+            for tid in (0, 3077):
+                print(f"    tid --> {tid}")
+                client = framer(ClientDecoder())
+                request = ReadHoldingRegistersRequest(124, 2, dev_id)
+                request.transaction_id = tid
+                result = client.buildPacket(request)
+                print(f"      request --> {result}")
+                print(f"      request --> {result.hex()}")
+                server = framer(ServerDecoder())
+                response = ReadHoldingRegistersResponse([141,142])
+                response.slave_id = dev_id
+                response.transaction_id = tid
+                result = server.buildPacket(response)
+                print(f"      response --> {result}")
+                print(f"      response --> {result.hex()}")
+                exception = request.doException(merror.IllegalAddress)
+                exception.transaction_id = tid
+                exception.slave_id = dev_id
+                result = server.buildPacket(exception)
+                print(f"      exception --> {result}")
+                print(f"      exception --> {result.hex()}")
+
+set_calls()

test/message/test_ascii.py

@@ -1,6 +1,4 @@
 """Test transport."""
-import struct
-
 import pytest
 
 from pymodbus.message.ascii import MessageAscii
@@ -16,24 +14,9 @@ def prepare_frame():
         return MessageAscii([1], False)
 
 
-    def test_check_LRC(self):
-        """Test check_LRC."""
-        data = struct.pack(">HHHH", 0x1234, 0x2345, 0x3456, 0x4567)
-        assert MessageAscii.check_LRC(data, 0x1C)
-
-    def test_check_noLRC(self):
-        """Test check_LRC."""
-        data = struct.pack(">HHHH", 0x1234, 0x2345, 0x3456, 0x4567)
-        assert not MessageAscii.check_LRC(data, 0x0C)
-
-    def test_compute_LRC(self):
-        """Test compute_LRC."""
-        data = struct.pack(">HHHH", 0x1234, 0x2345, 0x3456, 0x4567)
-        assert MessageAscii.compute_LRC(data) == 0x1c
-
     def test_roundtrip_LRC(self):
         """Test combined compute/check LRC."""
-        data = struct.pack(">HHHH", 0x1234, 0x2345, 0x3456, 0x4567)
+        data = b'\x12\x34\x23\x45\x34\x56\x45\x67'
         assert MessageAscii.compute_LRC(data) == 0x1c
         assert MessageAscii.check_LRC(data, 0x1C)