A problem with the SOAP logical tree format

Just one small step will complete my finding. It was the web service development on Message Broker. Ever wonder how things done and I always got an excuse to delay my finding.

Say I have a WSDL, which consist of following:

...

<wsdl:types>
  <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" targetNamespace="http://helloWorld.huahsin.org/">
    <xsd:element name="Input">
      <xsd:complexType>
        <xsd:sequence>
          <xsd:element name="name" type="xsd:string" minOccurs="1"/>
          <xsd:element name="age" type="xsd:integer" minOccurs="0"/>
        </xsd:sequence>
      </xsd:complexType>
    </xsd:element>
    <xsd:element name="Output">
      <xsd:complexType>
        <xsd:sequence>
          <xsd:element name="greetings" type="xsd:string" minOccurs="1"/>
        </xsd:sequence>
      </xsd:complexType>
    </xsd:element>
  </xsd:schema>
</wsdl:types>

...

Ignore those unnecessary stuff, let's focus only on the input and output. The above WSDL shows the following request input:

<soap:Envelope xmlns:soap="http://www.w3.org/2003/05/soap-envelope" xmlns:hel="http://helloWorld.huahsin.org/">
   <soap:Header/>
   <soap:Body>
      <hel:Input>
         <name>LKJ</name>
         <!--Optional:-->
         <age>0</age>
      </hel:Input>
   </soap:Body>
</soap:Envelope>

And the expected response message:

<soap:Envelope xmlns:soap="http://www.w3.org/2003/05/soap-envelope" xmlns:hel="http://helloWorld.huahsin.org/">
   <soap:Body>
      <hel:Output>
         <greetings>Hello World</greetings>
      </hel:Output>
   </soap:Body>
</soap:Envelope>

That's all about it. Somehow, things always out of expectation. I got this:

<soapenv:Envelope xmlns:soapenv="http://www.w3.org/2003/05/soap-envelope">
   <soapenv:Body>
      <soapenv:Fault>
         <soapenv:Code>
            <soapenv:Value>soapenv:Receiver</soapenv:Value>
         </soapenv:Code>
         <soapenv:Reason>
            <soapenv:Text xml:lang="en">BIP3113E: Exception detected in message flow Main.SOAP Input (broker brk2)</soapenv:Text>
         </soapenv:Reason>
         <soapenv:Node>://localhost:7080/HelloWorld</soapenv:Node>
         <soapenv:Detail>
            <Text>BIP3752E: The SOAP Reply node 'Main.SOAP Reply' encountered an error while processing a reply message. 
An error occurred during reply message processing. 
See previous error messages to determine the cause of the error. : F:\build\slot1\S800_P\src\WebServices\WSLibrary\ImbSOAPReplyNode.cpp: 397: ImbSOAPReplyNode::evaluate: ComIbmSOAPReplyNode: Main#FCMComposite_1_2
BIP3605E: The SOAP logical tree cannot be serialized. 
There is a problem with the SOAP logical tree format. 
Review further error messages for an indication to the cause of the error. Check that the SOAP logical supplied is correctly formatted. : F:\build\slot1\S800_P\src\WebServices\WSLibrary\ImbSOAPParser.cpp: 1360: ImbSOAPParser::refreshBitStreamFromElementsInner: : 
BIP3602E: The Web service payload ''{http://helloWorld.huahsin.org/}Input'' does not match an operation described by WSDL binding ''HelloWorldBinding'' in file ''huahsin.wsdl''. 
The first child of the SOAP Body does not correspond to any of the operations defined in the specified WSDL definition. 
Check that the correct WSDL definition was deployed. : F:\build\slot1\S800_P\src\WebServices\WSLibrary\ImbSOAPParser.cpp: 790: ImbSOAPParser::refreshBitStreamFromElementsInner: :</Text>
         </soapenv:Detail>
      </soapenv:Fault>
   </soapenv:Body>
</soapenv:Envelope>

At first I was so struggling to work on this error, luckily I got the solution during my work, The more I work, the more knowledge I learn. This was due to the message construction happened in Transform Node:

CREATE COMPUTE MODULE Main_Compute
  CREATE FUNCTION Main() RETURNS BOOLEAN
  BEGIN
    -- CALL CopyMessageHeaders();
    CALL CopyEntireMessage();

    DECLARE hel NAMESPACE 'http://helloWorld.huahsin.org/';

    SET OutputRoot.SOAP.Body.hel:Output.greetings = 'Hello World';

    RETURN TRUE;
  END;

  ...
END MODULE;

The error is from the OutputRoot. OutputRoot is the ultimate destination that the message will be reach at the end of the flow. During the message construction, any message that going to send out a response are advisable to clear them out. Like this:

    ...

    DELETE FIELD OutputRoot.SOAP.Body;
    SET OutputRoot.SOAP.Body.hel:Output.greetings = 'Hello World';

    ...

Leave the SOAP tree empty before any new message is constructed.