What does msg mean in Mirth?

Question

I am trying to find my way around some Mirth code. I continue to see such things in the transformer for different channels:

msg['PRB']['PRB.4']['PRB.4.2'].toString() 

I understand this is parsing an HL7 message, and I understand that msg probably means a message. But is MSG system-wide variable? Does each channel have an MSG variable? What is the scope of MSG ? I also see things like ${message.encodedData} in Templates. Are some connector types automatically sending MSG content?

Answer 1

msg variable - the current instance of the incoming message that you will use for routing or mapping. It exists only in the context of the transformation / transformation you are applying, and is not system-wide. The message to be transmitted is called tmp . So, when you do the mapping, you will go from msg → tmp.