fix #165, #174, #169, #175, #147, #146

pymodbus/exceptions.py

@@ -77,6 +77,21 @@ def __init__(self, string=""):
         message = "[Connection] %s" % string
         ModbusException.__init__(self, message)
 
+
+class InvalidResponseRecievedException(ModbusException):
+    """
+    Error resulting from invalid response received or decoded
+    """
+
+
+def __init__(self, string=""):
+    ''' Initialize the exception
+
+    :param string: The message to append to the error
+    '''
+    message = "[Invalid Response] %s" % string
+    ModbusException.__init__(self, message)
+
 #---------------------------------------------------------------------------#
 # Exported symbols
 #---------------------------------------------------------------------------#

pymodbus/mei_message.py

@@ -10,7 +10,7 @@
 from pymodbus.device import ModbusControlBlock
 from pymodbus.device import DeviceInformationFactory
 from pymodbus.pdu import ModbusExceptions as merror
-from pymodbus.compat import iteritems, byte2int
+from pymodbus.compat import iteritems, byte2int, IS_PYTHON3
 
 _MCB = ModbusControlBlock()
 
@@ -132,7 +132,13 @@ def encode(self):
 
         for (object_id, data) in iteritems(self.information):
             packet += struct.pack('>BB', object_id, len(data))
-            packet += data.encode()
+            if IS_PYTHON3:
+                if isinstance(data, bytes):
+                    packet += data
+                else:
+                    packet += data.encode()
+            else:
+                packet += data.encode()
         return packet
 
     def decode(self, data):

pymodbus/other_message.py

@@ -43,7 +43,7 @@ def decode(self, data):
         '''
         pass
 
-    def execute(self):
+    def execute(self, context=None):
         ''' Run a read exeception status request against the store
 
         :returns: The populated response
@@ -144,7 +144,7 @@ def decode(self, data):
         '''
         pass
 
-    def execute(self):
+    def execute(self, context=None):
         ''' Run a read exeception status request against the store
 
         :returns: The populated response
@@ -249,7 +249,7 @@ def decode(self, data):
         '''
         pass
 
-    def execute(self):
+    def execute(self, context=None):
         ''' Run a read exeception status request against the store
 
         :returns: The populated response
@@ -359,12 +359,12 @@ def decode(self, data):
         '''
         pass
 
-    def execute(self):
+    def execute(self, context=None):
         ''' Run a read exeception status request against the store
 
         :returns: The populated response
         '''
-        identifier = b'\x70\x79\x6d\x6f\x64\x62\x75\x73'
+        identifier = b'Pymodbus'
         return ReportSlaveIdResponse(identifier)
 
     def __str__(self):
@@ -392,14 +392,17 @@ def __init__(self, identifier=b'\x00', status=True, **kwargs):
         ModbusResponse.__init__(self, **kwargs)
         self.identifier = identifier
         self.status = status
+        self.byte_count = None
 
     def encode(self):
         ''' Encodes the response
 
         :returns: The byte encoded message
         '''
-        if self.status: status = ModbusStatus.SlaveOn
-        else: status = ModbusStatus.SlaveOff
+        if self.status:
+            status = ModbusStatus.SlaveOn
+        else:
+            status = ModbusStatus.SlaveOff
         length  = len(self.identifier) + 2
         packet  = int2byte(length)
         packet += self.identifier  # we assume it is already encoded
@@ -414,8 +417,8 @@ def decode(self, data):
 
         :param data: The packet data to decode
         '''
-        length = byte2int(data[0])
-        self.identifier = data[1:length + 1]
+        self.byte_count = byte2int(data[0])
+        self.identifier = data[1:self.byte_count + 1]
         status = byte2int(data[-1])
         self.status = status == ModbusStatus.SlaveOn
 
@@ -425,7 +428,7 @@ def __str__(self):
         :returns: The string representation of the response
         '''
         arguments = (self.function_code, self.identifier, self.status)
-        return "ResportSlaveIdResponse(%d, %d, %d)" % arguments
+        return "ResportSlaveIdResponse(%s, %s, %s)" % arguments
 
 #---------------------------------------------------------------------------#
 # TODO Make these only work on serial

pymodbus/transaction.py

@@ -7,6 +7,7 @@
 from binascii import b2a_hex, a2b_hex
 
 from pymodbus.exceptions import ModbusIOException, NotImplementedException
+from pymodbus.exceptions import InvalidResponseRecievedException
 from pymodbus.constants  import Defaults
 from pymodbus.interfaces import IModbusFramer
 from pymodbus.utilities  import checkCRC, computeCRC
@@ -107,7 +108,6 @@ def execute(self, request):
         retries = self.retries
         request.transaction_id = self.getNextTID()
         _logger.debug("Running transaction %d" % request.transaction_id)
-
         expected_response_length = None
         if hasattr(request, "get_response_pdu_size"):
             response_pdu_size = request.get_response_pdu_size()
@@ -116,12 +116,12 @@ def execute(self, request):
 
         while retries > 0:
             try:
+                last_exception = None
                 self.client.connect()
                 packet = self.client.framer.buildPacket(request)
                 if _logger.isEnabledFor(logging.DEBUG):
                     _logger.debug("send: " + " ".join([hex(byte2int(x)) for x in packet]))
                 self.client._send(packet)
-
                 exception = False
                 result = self.client._recv(expected_response_length or 1024)
                 while result and expected_response_length and len(result) < expected_response_length:
@@ -139,12 +139,18 @@ def execute(self, request):
                     _logger.debug("recv: " + " ".join([hex(byte2int(x)) for x in result]))
                 self.client.framer.processIncomingPacket(result, self.addTransaction)
                 break
-            except socket.error as msg:
+            except (socket.error, ModbusIOException, InvalidResponseRecievedException) as msg:
                 self.client.close()
                 _logger.debug("Transaction failed. (%s) " % msg)
                 retries -= 1
-        return self.getTransaction(request.transaction_id)
+                last_exception = msg
+        response = self.getTransaction(request.transaction_id)
+        if not response:
+            last_exception = last_exception or ("No Response "
+                                                "received from the remote unit")
+            response = ModbusIOException(last_exception)
 
+        return response
 
     def addTransaction(self, request, tid=None):
         ''' Adds a transaction to the handler
@@ -432,9 +438,12 @@ def _process(self, callback, error=False):
         result = self.decoder.decode(data)
         if result is None:
             raise ModbusIOException("Unable to decode request")
-        self.populateResult(result)
-        self.advanceFrame()
-        callback(result)  # defer or push to a thread?
+        elif error and result.function_code < 0x80:
+            raise InvalidResponseRecievedException(result)
+        else:
+            self.populateResult(result)
+            self.advanceFrame()
+            callback(result)  # defer or push to a thread?
 
     def resetFrame(self):
         ''' Reset the entire message frame.
@@ -670,9 +679,12 @@ def _process(self, callback, error=False):
         result = self.decoder.decode(data)
         if result is None:
             raise ModbusIOException("Unable to decode request")
-        self.populateResult(result)
-        self.advanceFrame()
-        callback(result)  # defer or push to a thread?
+        elif error and result.function_code < 0x80:
+            raise InvalidResponseRecievedException(result)
+        else:
+            self.populateResult(result)
+            self.advanceFrame()
+            callback(result)  # defer or push to a thread?
 
     def getRawFrame(self):
         """
@@ -811,7 +823,8 @@ def processIncomingPacket(self, data, callback):
                 self.populateResult(result)
                 self.advanceFrame()
                 callback(result)  # defer this
-            else: break
+            else:
+                break
 
     def buildPacket(self, message):
         ''' Creates a ready to send modbus packet
@@ -972,7 +985,8 @@ def processIncomingPacket(self, data, callback):
                 self.populateResult(result)
                 self.advanceFrame()
                 callback(result)  # defer or push to a thread?
-            else: break
+            else:
+                break
 
     def buildPacket(self, message):
         ''' Creates a ready to send modbus packet

test/test_other_messages.py

@@ -92,7 +92,7 @@ def testReportSlaveId(self):
         self.assertEqual(request.execute().function_code, 0x11)
 
         response = ReportSlaveIdResponse(request.execute().identifier, True)
-        self.assertEqual(response.encode(), b'\x0apymodbus\xff')
+        self.assertEqual(response.encode(), b'\x0aPymodbus\xff')
         response.decode(b'\x03\x12\x00')
         self.assertEqual(response.status, False)
         self.assertEqual(response.identifier, b'\x12\x00')