Parsing SOAP Message with XmlSlurper and Adding Value to Header Field to Send to Backend

import groovy.xml.XmlSlurper
import groovy.xml.XmlUtil
import groovy.xml.StreamingMarkupBuilder

try {
  def namespacePrefix = 'sch'
  def namespaceUri = 'http://kurum.com/ws/some-func-ws/schemas'
  def userName = request_usernameOrKey

  // Parse XML using XmlSlurper and define namespaces
  def rootNode = new XmlSlurper(false, true).parseText(requestBodyTextFromClient).declareNamespace(
    'soapenv': 'http://schemas.xmlsoap.org/soap/envelope/',
    'sch': 'http://kurum.com/ws/some-func-ws/schemas'
  )

  // Check if Header section exists, create if not
  def headerNode = rootNode.'soapenv:Header'
  if (!headerNode) {
    headerNode = rootNode.appendNode { 'soapenv:Header' {} }
  }

  // Create and add userId element
  def userIdNode = new XmlSlurper(false, true).parseText("<${namespacePrefix}:userId xmlns:${namespacePrefix}='${namespaceUri}'>${userName}</${namespacePrefix}:userId>")
  headerNode.appendNode { mkp.yield userIdNode }

  // Serialize updated XML as string
  def outputXml = XmlUtil.serialize(new StreamingMarkupBuilder().bind {
    mkp.declareNamespace('soapenv': 'http://schemas.xmlsoap.org/soap/envelope/', 'sch': 'http://kurum.com/ws/some-func-ws/schemas')
    mkp.yield rootNode
  })

  requestBodyTextToTargetAPI = outputXml
} catch (Exception e) {
  e.printStackTrace()
}