I'm having trouble parsing an XML response from a web service. I have a feeling this is due to a namespace issue. But, after 4 hours of research, trial-and-error, and head-banging I haven't been able to resolve it. Please help.

My goal is to get a dbms_xmldom.DOMNodeList that contains "ERRORS" nodes.

XML Response:

<?xml version="1.0" encoding="ISO-8859-1"?>
<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<soap:Body>
    <GetMailDataResponse xmlns="https://www.customnamespacehost.com/webservicename">
        <GetMailDataResult>
            <Errors xmlns="">
                <ErrorDetail>Access Credentials Invalid</ErrorDetail>
            </Errors>
        </GetMailDataResult>
    </GetMailDataResponse>
</soap:Body>

Code:

Unfortunately this code compiles but doesn't work. Error: "ORA-31013: Invalid XPATH expression." I believe this is due to the multiple namespaces defined in L_NS variable. I tried setting L_XPATH: "/soap:Envelope/soap:Body" and L_NS: "xmlns:soap="http://schemas.xmlsoap.org/soap/envelope"" but L_NL_RESULTS ends up being null.

-- Variable Declarations --

P_XML XMLTYPE;

L_CODE_NAME VARCHAR2(1000) := 'PKG_CIS_WS.FNC_STAGE_DATA';

L_XML_DOC                         dbms_xmldom.DOMDocument; 


L_NL_RESULTS                      dbms_xmldom.DOMNodeList;
L_NL_DONOR_SCREENING_RESULTS      dbms_xmldom.DOMNodeList;

L_N_RESULT                        dbms_xmldom.DOMNode;

L_XPATH                           VARCHAR2(4000);
L_NS                              VARCHAR2(4000);
L_TEMP                            VARCHAR2(4000);

-- Code Snippet --   

L_XML_DOC := dbms_xmldom.newDOMDocument(P_XML); 

L_XPATH :=  '/soap:Envelope/soap:Body/a:GetMailDataResponse/GetMailDataResult';
L_NS    :=  'xmlns:soap="http://schemas.xmlsoap.org/soap/envelope"' ||
            'xmlns:a="https://www.customnamespacehost.com/webservicename"';

L_NL_RESULTS := dbms_xslprocessor.selectNodes(
    dbms_xmldom.makeNode(L_XML_DOC)
  , L_XPATH
  , L_NS);

if not DBMS_XMLDOM.ISNULL(L_NL_RESULTS) then

  FOR RESULTS_REC IN 0 .. dbms_xmldom.getLength(L_NL_RESULTS) - 1 LOOP

    L_N_RESULT := dbms_xmldom.item(L_NL_RESULTS, RESULTS_REC); 

    L_TEMP := dbms_xmldom.GETNODENAME(L_N_RESULT);

    prc_bjm(L_CODE_NAME, 'L_TEMP = ' || L_TEMP, SQLCODE);

    dbms_xslprocessor.valueOf(L_N_RESULT, 'Errors/ErrorDetail/text()', L_TEMP);

    prc_bjm(L_CODE_NAME, 'L_TEMP = ' || L_TEMP, SQLCODE);

  END LOOP;

else

  prc_bjm(L_CODE_NAME, 'No nodes for: ' || L_XPATH || '(' || L_NS || ')', SQLCODE);

end if; -- if not DBMS_XMLDOM.ISNULL(L_NL_RESULTS)