• Introduction
• Task
• Implementation
• How it works
• More information

Introduction

Our HL7 Simulator is a Windows only tool so it is not convenient to use it on the other operating systems like Mac or Linux. A simple solution to this problem is to create a channel that reads HL7 messages from a file and forwards them using an LLP Client destination (this works on all operating systems).

Task [top]

Create a channel to read HL7 messages from a file and forward them using an LLP Client destination.  In the example code shown here we use the HL7 sample messages that are included with the Iguana install — <iguana install dir>/Demo/sample_data.txt.

Implementation [top]

1. Create a channel named HL7 LLP simulator (or similar).
   • Source: From Translator
   • Destination: LLP Client
2. Paste this code into the From Translator:

   -- NOTE: using the "/" forward slash in the path works Windows as well 
   SAMPLE_DATA = iguana.workingDir()..'Demo/sample_data.txt'
   
   function main()
      -- open the sample data file
      local f = io.open(SAMPLE_DATA)
      
      -- read & queue each message
      while true do
         -- uncomment to pause between messages
         --util.sleep(1000) -- 1000 = 1 second
         local r = f:read()
         if r == nil then 
            break 
         else
            queue.push{data=r}
         end
      end
   end

3. Save a commit.
4. identify the Port, in the LLP Client destination properties (default = 5145):
   
5. Create another channel with an LLP Listener source and use the port from the previous step:
   
6. Start your Listener channel.
7. Start your LLP Simulator channel and then stop it immediately.

   Stopping the HL7 Simulator channel immediately after starting ensures that you will only send the file of (282) sample messages a single time. You can leave the channel running if you wish but every time the channel polls it will send all the messages in the file again — this is ok if you wish to send the messages repeatedly.

How it works [top]

1. The channel uses the sample_data.txt included in the Iguana install.

   The code automatically finds the HL7 sample message file (<iguana install dir>/Demo/sample_data.txt) that is included with the Iguana install.

2. Each message is then read in from the file using f:read().

   This works because each HL7 message is stored as a line in the sample data file (sample_data.txt). If you want to use the code with your own file you will need to ensure that each message is on one line (i.e., using a LF or /n to separate the messages).

   

3. Each message is queued.
4. When the end of file is reached (r=nil) the loop exits and processing stops.
5. Queued messages are sent out as LLP messages by the LLP Client destination.

More information [top]

• Sending and receiving HL7 test messages
• Using the HL7 Simulator on Linux and Mac