Calling web service fail from PL/SQL - web-services

Question

I just want to call a web service from PL/SQL, so I create a web service :
http://localhost:64955/Service1.asmx?op=add
firstly, the web methods are very simple,like below:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Services;
namespace Calculator
{
/// <summary>
/// Summary description for Service1
/// </summary>
[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[System.ComponentModel.ToolboxItem(false)]
// To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line.
// [System.Web.Script.Services.ScriptService]
public class Service1 : System.Web.Services.WebService
{
[WebMethod]
public string HelloWorld()
{
return "Hello World";
}
[WebMethod]
public int add(int firstNum, int secondNum)
{
return firstNum + secondNum;
}
}
}
and I want to invoke the second method(add) in the web service, so I write my PL/SQL code like this:
declare
l_param_list varchar2(512);
l_http_request UTL_HTTP.req;
l_http_response UTL_HTTP.resp;
l_response_text varchar2(32000);
begin
-- service's input parameters
l_param_list := 'firstNum=1'||'&'||'secondNum=2';
--http://localhost:64955/Service1.asmx?op=add
--16.158.161.7
-- prepareint Request...
l_http_request := UTL_HTTP.begin_request ('http://localhost:64955/Service1.asmx?op=add'
,'POST'
,'HTTP/1.1');
--...set header's attributes
UTL_HTTP.set_header(l_http_request,'Content-Type', 'application/x-www-form-urlencoded');
UTL_HTTP.set_header(l_http_request,'Content-Length', length(l_param_list));
--...set input parameters
UTL_HTTP.write_text(l_http_request, l_param_list);
-- get response and obtain received value
l_http_response := UTL_HTTP.get_response(l_http_request);
UTL_HTTP.read_text(l_http_response, l_response_text);
dbms_output.put_line(l_response_text);
dbms_output.put_line('test1');
--finalizing
UTL_HTTP.end_response(l_http_response);
exception
when UTL_HTTP.end_of_body then
UTL_HTTP.end_response(l_http_response);
dbms_output.put_line('test2');
end;
But when I run this PL/SQL code segment, I got some exceptions:
<?xml version="1.0" encoding="utf-8"?><soap:Envelope xmlns:soap="http://www.w3.org/2003/05/soap-envelope" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"><soap:Body><soap:Fault><soap:Code><soap:Value>soap:Receiver</soap:Value></soap:Code><soap:Reason><soap:Text xml:lang="en">System.Web.Services.Protocols.SoapException: Server was unable to process request. ---> System.Xml.XmlException: Root element is missing.
at System.Xml.XmlTextReaderImpl.Throw(Exception e)
at System.Xml.XmlTextReaderImpl.ThrowWithoutLineInfo(String res)
at System.Xml.XmlTextReaderImpl.ParseDocumentContent()
at System.Xml.XmlTextReaderImpl.Read()
at System.Xml.XmlTextReader.Read()
at System.Web.Services.Protocols.SoapServerProtocol.SoapEnvelopeReader.Read()
at System.Xml.XmlReader.MoveToContent()
at System.Web.Services.Protocols.SoapServerProtocol.SoapEnvelopeReader.MoveToContent()
at System.Web.Services.Protocols.SoapServerProtocolHelper.GetRequestElement()
at System.Web.Services.Protocols.Soap12ServerProtocolHelper.RouteRequest()
at System.Web.Services.Protocols.SoapServerProtocol.RouteRequest(SoapServerMessage message)
at System.Web.Services.Protocols.SoapServerProtocol.Initialize()
at System.Web.Services.Protocols.ServerProtocol.SetContext(Type type, HttpContext context, HttpRequest request, HttpResponse response)
at System.Web.Services.Protocols.ServerProtocolFactory.Create(Type type, HttpContext context, HttpRequest request, HttpResponse response, Boolean& abortProcessing)
--- End of inner exception stack trace ---</soap:Text></soap:Reason><soap:Detail /></soap:Fault></soap:Body></soap:Envelope>
test1
I am a beginner on the PL/SQL, so can anybody tell me what's wrong with my code?
BTW, the web service can be invoked normally from a windows form application.

Answer 1

The problem is that your webservice is SOAP , but you are not sending a SOAP request.
To do this, check the wsdl of your webservice, by browsing this URL http://localhost:64955/Service1.asmx?wsdl ,from there you will know how to create the SOAP envelop to call your webmethod.
you would do something like :
soap_request :=
'<SOAP-ENV:Envelope
xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
<SOAP-ENV:Body>
<m:add xmlns:m="Some-URI">
<firstNum>1</firstNum>
<secondNum>2</secondNum>
</m:add>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>';
l_http_request := UTL_HTTP.begin_request ('http://localhost:64955/Service1.asmx?op=add'
,'POST'
,'HTTP/1.1');
--...set header's attributes
UTL_HTTP.set_header(l_http_request,'Content-Type', 'application/xml');
UTL_HTTP.set_header(l_http_request,'Content-Length', length(soap_request));
--...set input parameters
UTL_HTTP.write_text(l_http_request, soap_request);
-- get response and obtain received value
l_http_response := UTL_HTTP.get_response(l_http_request);
UTL_HTTP.read_text(l_http_response, l_response_text);
dbms_output.put_line(l_response_text);
dbms_output.put_line('test1');
--finalizing
UTL_HTTP.end_response(l_http_response);