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Step 3 - Creating the Python Script |
Now that you have a VMD file that recognizes incoming ADT^A17 messages, the next step is to write the Python transformation script that generates the ADT^A02 output messages.
- In Chameleon, from the Workspace panel at the left, double-click Transformation Script. An Editing Script window appears.
- Type or copy the script shown below. Replace the C:/output/ output directory shown in the example below with the path of the directory into which you want to store the output messages. Click Ok when done.
from ifware import guid
# Function to write a message to a file
def flush_new_message(message, outputDirectory, extension):
fileName = guid.generate_guid(128)
outfilename = outputDirectory + fileName + extension
f=open(outfilename, 'wb')
f.write(message)
f.close()
# Initialize the newMessage variable prior to processing the next Inbound
# message. Otherwise, Chameleon would remember the value of newMessage from
# the previously processed message, if any such message exists.
newMessage = None
# Specify the default location for output files
outputDirectory = "c:/output/"
# Specify the file name extension for output files
extension = ".txt"
# Initialize iterator
current_segment = environment.input_segment_iterator()
# Current segment becomes MSH.
# Apply segment scripts if they exist
current_segment.apply_transform()
# Modify Message Type to be ADT^A02
current_segment.field(9).value = 'ADT^A02'
output = current_segment.output()
while current_segment.move_one():
# Append each segment which repeats with each of future A02 messages
if current_segment.segment_id()[0:3] in ('SFT', 'EVN'):
# apply segment scripts if they exist
current_segment.apply_transform()
output = output + current_segment.output()
# Reset the iterator to parse the message again
# current segment becomes MSH
current_segment.reset()
while current_segment.move_one():
if current_segment.segment_id()[0:3] == 'PID':
# Apply segment scripts if they exist
current_segment.apply_transform()
if newMessage == None:
# On first pass, the new message doesn't exist, so
# we assign newMessage a value and initialize it, but
# don't flush the message to a file.
newMessage = output + current_segment.output()
else:
# On any other pass, the newMessage variable already has a
# value, so we flush the new message content to a file.
flush_new_message(newMessage, outputDirectory, extension)
# Re-initialize the newMessage variable.
newMessage = output + current_segment.output()
if current_segment.segment_id()[0:2] == 'PV':
# Apply segment scripts if they exist
current_segment.apply_transform()
newMessage = newMessage + current_segment.output()
# Flush last remaining new message to file
flush_new_message(newMessage, outputDirectory, extension)
# If we don't want any messages to be output by this Scripted Transformation,
# the special variable "value" can be assigned the empty string.
value = ''
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Here's how this script works:
- The script uses the built-in functions environment.input_segment_iterator() and current_segment.move_one() to examine each of the segments in the input ADT^A17 message. It creates an output variable consisting of the MSH, SFT and EVN segments. These segments are included in every ADT^A02 output message.
- The script then calls current_segment.reset() to go back to the start of the ADT^A17 message. When it finds a PID segment, it creates a variable named newMessage. This variable contains one ADT^A02 output message, and is initialized to contain the MSH, SFT, EVN and PID segments.
- If the script finds a segment whose type starts with "PV" (such as PV1 or PV2), the segment is added to the contents of newMessage.
- At this point, the script has either reached the end of the message or a new PID segment has been found. If this is the end of the message, the contents of the newMessage variable are written to an output file. If a new PID segment has been found, newMessage is written to an output file and is reinitialized to contain the MSH, SFT and EVN segments along with the new PID segment. The process is then repeated.
- To ensure that each output file has a unique file name, the function guid.generate_guid() is called. This function generates a 32-byte hex-encoded globally unique identifier, which is represented as a character string. This character string is used as the file name.
Here is a sample output ADT^A02 message generated by this script:
MSH|^~\&|MESA_ADT|XYZ_ADMITTING|MESA_IS|XYZ_HOSPITAL|200004240100||ADT^A02|1024|P|2.5| SFT|abc|123|def|456| EVN||200706041047||||200706041043| PID|||583020||WHITE^CHARLES||19020704|M||AI|7616 STANFORD AVE^^ST. LOUIS^MO^63130|||||||20-98-1701| PV1||E|PATIENT_LOCATION||||ATTENDING_DOCTOR|5101^NELL^FREDERICK^P^^DR|||||||||||V1102^^^ADT1|||||||||||||||||||||||||200004230800| PV2||W|COPDADTHI| |
This file contains the MSH, SFT and EVN segments from the ADT^A17 input message, along with one PID segment and its associated PV1 and PV2 segments.
Your VMD file is now able to split ADT^A17 input messages into multiple ADT^A02 output messages.
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For more information, see the following sections:
If you are having trouble creating the VMD file for this tutorial, you can use this sample VMD file: splitmsg.vmd. | ||
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