Added .Close() to close the session with the PLC. Scripts should use …

…this now to properly close the session. See the updated README

README

@@ -35,14 +35,16 @@ USAGE - Python 2.7.11
 	ex:  stuff = test.Discover()
 	     print stuff(1).IPAddress # prints the first devices IP Address
 
-
+5) Close the connection with test.Close()
+
 So a complete script to read a tag would look like this:
 
 from eip import PLC
 test = PLC()
 test.IPAddress = "192.168.1.64"
 value = test.Read("MyTimer.ACC")
 print value
+test.Close()
 
 
 
@@ -84,4 +86,4 @@ In order to perform a typical read/write, the data type needs to be known, or
     data type.  This helps us in two ways:  First, the user won't need to specify
     the data type.  Second, we can keep track of this information so the next
     time the particular tag is called, we already know it's type so we can just
-    do the normal read/write (0x4C/0x4D/0x4E).
+    do the normal read/write (0x4C/0x4D/0x4E).

changelog

@@ -1,15 +1,19 @@
+10/27/16
+  -Added .Close() to close the session with the PLC. Whenever a script is done
+    .Close() should be called.
+
 10/26/16
-  Added _getBytes() for sending/receiving data.  Should handle failure better
-  Rewrote _connect() to handle disconnect/reconnects better
+  -Added _getBytes() for sending/receiving data.  Should handle failure better
+  -Rewrote _connect() to handle disconnect/reconnects better
 
 08/17/16
-  Fixed tagIOI not dealing with greater than 4 byte tag index
+  -Fixed tagIOI not dealing with greater than 4 byte tag index
 
 08/05/16
-  Fixed derp with calling _getTagList
+  -Fixed derp with calling _getTagList
 
 07/29/16
-  Fixed writing to boolean array
+  -Fixed writing to boolean array
 
 07/27/16
   -Fixed defaulting to element zero when writing to an array value
@@ -180,4 +184,4 @@
 03/14/2015
   -Removed duplicate CIPTagReadRequest function (from testing)
   -Initial commit
-
+

eip.py

@@ -110,6 +110,11 @@ def Discover(self):
         '''
         return _discover()
 
+    def Close(self):
+        '''
+        Close the connection to the PLC
+        '''
+        return _closeConnection(self)
 
 class LGXTag():
 
@@ -369,6 +374,19 @@ def _connect(self):
 	print "Forward Open Failed"
 	return
 
+def _closeConnection(self):
+    '''
+    Close the connection to the PLC (forward close, unregister session)
+    '''
+    closePacket = _buildForwardClosePacket(self)
+    unregPacket = _buildUnregisterSession(self)
+    retData = _getBytes(self, closePacket)
+    retData = _getBytes(self, unregPacket)
+    try:
+        self.Socket.close()
+    except:
+        pass 
+
 def _getBytes(self, data):
     '''
     Sends data and gets the return data
@@ -382,11 +400,9 @@ def _getBytes(self, data):
             return None
     except socket.gaierror, e:
 	self.SocketConnected = False
-	print e
         return None
     except IOError, e:
 	self.SocketConnected = False
-	print e
 	return None
 
 def _buildRegisterSession(self):
@@ -413,6 +429,22 @@ def _buildRegisterSession(self):
                 EIPProtocolVersion,
                 EIPOptionFlag)
 
+def _buildUnregisterSession(self):
+    EIPCommand = 0x66                       #(H)
+    EIPLength = 0x00                        #(H)
+    EIPSessionHandle = self.SessionHandle   #(I)
+    EIPStatus = 0x0000                      #(I)
+    EIPContext = self.Context               #(Q)
+    EIPOptions = 0x0000                     #(I)
+
+    return pack('<HHIIQI',
+                EIPCommand,
+                EIPLength,
+                EIPSessionHandle,
+                EIPStatus,
+                EIPContext,
+                EIPOptions)
+
 def _buildForwardOpenPacket(self):
     '''
     Assemble the forward open packet
@@ -421,6 +453,14 @@ def _buildForwardOpenPacket(self):
     rrDataHeader = _buildEIPSendRRDataHeader(self, len(forwardOpen))
     return rrDataHeader+forwardOpen
 
+def _buildForwardClosePacket(self):
+    '''
+    Assemble the forward close packet
+    '''
+    forwardClose = _buildForwardClose(self)
+    rrDataHeader = _buildEIPSendRRDataHeader(self, len(forwardClose))
+    return rrDataHeader + forwardClose
+
 def _buildCIPForwardOpen(self):
     '''
     Forward Open happens after a connection is made,
@@ -488,6 +528,41 @@ def _buildCIPForwardOpen(self):
                 CIPConnectionPathSize,
                 CIPConnectionPath[0],CIPConnectionPath[1],CIPConnectionPath[2],CIPConnectionPath[3],
                 CIPConnectionPath[4],CIPConnectionPath[5])
+
+def _buildForwardClose(self):
+    CIPService = 0x4E                                    #(B) CIP OpenForward        Vol 3 (3-5.5.2)(3-5.5)
+    CIPPathSize = 0x02                                   #(B) Request Path zize              (2-4.1)
+    CIPClassType = 0x20                                  #(B) Segment type                   (C-1.1)(C-1.4)(C-1.4.2)
+                                                         #[Logical Segment][Class ID][8 bit addressing]
+    CIPClass = 0x06                                      #(B) Connection Manager Object      (3-5)
+    CIPInstanceType = 0x24                               #(B) Instance type                  (C-1.1)
+
+    CIPInstance = 0x01                                   #(B) Instance
+    CIPPriority = 0x0A                                   #(B) Timeout info                   (3-5.5.1.3)(3-5.5.1.2)
+    CIPTimeoutTicks = 0x0e                               #(B) Timeout Info                   (3-5.5.1.3)
+    CIPConnectionSerialNumber = self.SerialNumber        #(H) Serial number for THIS connection (3-5.5.1.4)
+    CIPVendorID = self.VendorID                          #(H)
+    CIPOriginatorSerialNumber = self.OriginatorSerialNumber  #(I)
+    CIPConnectionPathSize = 0x03                         #(B)                                   (3-5.5.1.9)
+    CIPReserved = 0x00                                   #(B)
+    CIPConnectionPath = (0x01,self.ProcessorSlot,0x20,0x02,0x24,0x01) #(6B) Compressed / Encoded Path  (C-1.3)(Fig C-1.2)
+
+    return pack('<BBBBBBBBHHIBB6B', CIPService,
+                CIPPathSize,
+                CIPClassType,
+                CIPClass,
+                CIPInstanceType,
+                CIPInstance,
+                CIPPriority,
+                CIPTimeoutTicks,
+                CIPConnectionSerialNumber,
+                CIPVendorID,
+                CIPOriginatorSerialNumber,
+                CIPConnectionPathSize,
+                CIPReserved,
+                CIPConnectionPath[0], CIPConnectionPath[1],
+                CIPConnectionPath[2], CIPConnectionPath[3],
+                CIPConnectionPath[4], CIPConnectionPath[5])
 
 def _buildEIPSendRRDataHeader(self, frameLen):
     EIPCommand = 0x6F                               #(H)EIP SendRRData  (Vol2 2-4.7)