mirth connect Database Reader automatic column mapping

Please could somebody confirm the following.. I am using Mirth Connect 3.5.08232. My Source Connector is a Database Reader.

Say, I am using a query that returns multiple rows, and return the result (via JavaScript), as documentation suggests, so that Mirth would treat each row as a separate message. I also use a couple of mappers as source transformers, and save the mapped fields in my channel map (which ends up to contain only those fields that I define in transformers)

In the destination, and specifically, in destination response transformer (or destination body, if it is a JavaScript writer), how do I access the source fields?

the only way I found by trial and error is

var rawMsg = connectorMessage.getRawData();
var xmlMsg = new XML(rawMsg);
logger.info(xmlMsg.some_field); // ignore the root element of rawMsg

Is this the right way to do this? I thought that maybe the fields that were nicely automatically detected would be put in some kind of a map, like sourceMap - but that doesn't seem to be the case, right?

Thank you

If you are using Mapper steps in your transformer to extract the data and put it into a variable map (like the channel map), then you can use any of the following methods to retrieve it from a subsequent JavaScript context (including a JavaScript Writer, and your response transformer):

var value = channelMap.get('key');
var value = $c('key');
var value = $('key');

Look at the Variable Maps section of the User Guide for more information.

So to recap, say you're selecting a column "mycolumn" with a Database Reader. The XML sent to the channel will be something like this:

<result>
    <mycolumn>value</mycolumn>
</result>

Then you can choose to extract pieces of that message into specific variables for later use. The transformer allows you to easily drag-and-drop pieces of the sample inbound message.

Finally in your JavaScript Writer (or in any subsequent filter, transformer, or response transformer), just drag the value into the field you want:

And the corresponding JavaScript code will automatically be inserted:

One last note, if you are selecting a lot of variables and don't want to make Mapper steps for each one individually, you can use a JavaScript Step to iterate through the message and extract each column into a separate map variable:

for each (child in msg.children()) {
    channelMap.put(child.localName(), child.toString());
}

Or, you can just reference the columns directly from within the JavaScript Writer:

var msg = new XML(connectorMessage.getEncodedData());

var column1 = msg.column1.toString();
var column2 = msg.column2.toString();
...