WSO2 iterative get-property from vfs file - loops

Question

I'm using WSO2 with the VFS. I need to take the incoming file, fileinput.xml and log the id fields together. The VFS is enabled and functional and when I move my fileinput.xml into my test_in folder it appropriately gets handled and put into test_out or test_failure correctly. I've read a lot of online documentation but have been unable to wrap my head around how to do the following.
My Question is
How do I get a property from my fileinput.xml ?
How do I iterate over the ids and concatenate them together in a log?
fileinput.xml
<soapenv:Envelope
xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
<soapenv:Header/>
<soapenv:Body>
<customers>
<customer>
<id>testid1</id>
<prop1>a</prop1>
<prop2>b</prop2>
<customer/>
<customer>
<id>testid2</id>
<prop1>3</prop1>
<prop2>4</prop2>
<customer/>
</customers>
</soapenv:Body>
</soapenv:Envelope>
My wso2 proxy file
<?xml version="1.0" encoding="UTF-8"?>
<proxy
xmlns="http://ws.apache.org/ns/synapse" name="FileProxy" transports="vfs" startOnLoad="true" trace="disable">
<target>
<parameter name="transport.vfs.ActionAfterProcess">MOVE</parameter>
<parameter name="transport.vfs.ActionAfterFailure">MOVE</parameter>
<parameter name="transport.PollInterval">5</parameter>
<parameter name="transport.vfs.FileURI">file:///Users/myuser/test_in</parameter>
<parameter name="transport.vfs.MoveAfterProcess">file:///Users/myusertest_out</parameter>
<parameter name="transport.vfs.MoveAfterFailure">file:///Users/myuser/test_failure</parameter>
<parameter name="transport.vfs.FileNamePattern">.*.xml</parameter>
<parameter name="transport.vfs.ContentType">text/xml</parameter>
<inSequence>
<log category="WARN" level="full">
<property name="MESSAGE" value="In Sequence"/>
</log>
<clone>
<target sequence="fileWriteSequence"/>
</clone>
</inSequence>
</target>
<outSequence>
<log category="WARN" level="full">
<property name="MESSAGE" value="Out Sequence"/>
</log>
<send/>
</outSequence>
</proxy>
My fileWriteSequence
<?xml version="1.0" encoding="UTF-8"?>
<sequence name="fileWriteSequence">
<log level="full">
<property name="sequence" value="fileWriteSequence"/>
</log>
<property name="transport.vfs.ReplyFileName" expression="fn:concat(fn:substring-after(get-property('MessageID'), 'urn:uuid:'), '.txt')" scope="transport"/>
<property name="OUT_ONLY" value="true"/>
<send>
<endpoint name="FileEpr">
<address uri="vfs:file:///Users/myuser/test_out"/>
</endpoint>
</send>
</sequence>

Answer 1

You can use the iterate mediator to iterate over 'id' element and use a property in the operation scope to concatenate all the id values. Refer this