Now that you have a VMD file, the next step is to write a Python script to detect duplicate messages:

• From the Chameleon menu, select Global Inbound Script. A Global Inbound Script window appears:

• In the Global Inbound Script window, paste or type the following Python code:

try:
    if value == LastMessage:
        segments = value.split("\r")
        MSH_fields = segments[0].split("|")
        MSH_fields[8] += "^DUPLICATE"
        segments[0] = "|".join(MSH_fields)
        value = "\r".join(segments)
    else:
        LastMessage = value
except NameError:
    LastMessage = value

• Click Ok to close the Global Inbound Script window.

Here's how this script works:

• The last message processed is saved in a variable named LastMessage.

• When a new message is received, it is compared with the contents of LastMessage.

• If the two messages are identical, the new message is a duplicate. It is broken into segments, the MSH.9.3 subfield is set to DUPLICATE, and the message is reassembled.

When the MSH.9.3 subfield is set to DUPLICATE, it will be matched by the DuplicateMessage message definition that you created earlier.

• From the File menu, select Save to save your VMD file.

At this point, the VMD file is ready for use. The next step is to create a channel that uses this VMD file to filter duplicate messages.

	If you are having trouble creating the VMD file for this tutorial, you can use this sample VMD file: ignoreduplicate.vmd.

	You can easily modify this code to write a message to the log file when a duplicate message is detected: try: if value == LastMessage: print "ALERT - DUPLICATE TRANSACTION OCCURRED" segments = value.split("\r") MSH_fields = segments[0].split("|") MSH_fields[8] += "^DUPLICATE" segments[0] = "|".join(MSH_fields) value = "\r".join(segments) else: LastMessage = value except NameError: LastMessage = value You can then follow the instructions in the Creating the Email Notification Rule section of the Detecting Duplicate Messages tutorial to create a notification rule to send an email message when a duplicate is detected.