Reading SOAP Request Attachment using Groovy

I figured it out. Let me first state what I wanted to do.

I wanted to get the SHA-256 value from the cached attachment in my SOAP Request and then place that value in the SOAP Request as a property. If the attachment changes it doesnt matter because the test will generate a new hash value from it. 

To do this:

     1. I created a Groovy Script test step to go get the attachment, generate the SHA-256 value and return it.

import java.security.MessageDigest
import java.math.BigInteger
	
	def attachment = testRunner.testCase.testSteps['SOAP_Request'].httpRequest.getAttachmentAt(0).data
	String sha256 = org.apache.commons.codec.digest.DigestUtils.sha256Hex(attachment);
	assert sha256
	return sha256

	log.info(sha256)

     2. I created a Property Transfer test step to move the "result" property value to a property I created at the Test Case level. 

     3. I then reference the custom Test Case property in my SOAP Request by using ${#TestCase#sha256}       (where sha256 is the name I gave the custom proerty) in the corresponding XML element.