SOAP::Lite, I don't get it

[gargle]

My fellow Monks,

After a few tries I'm able to communicate correctly with a webservice here at work. The following code works:

#!/usr/bin/perl

use strict;
use warnings;

use Readonly;
use SOAP::Lite +trace => "debug";
use Data::Dumper;

Readonly my $SOAPURL => 'http://the.webservice/service/pers?wsdl';

my $service = SOAP::Lite->service($SOAPURL);

my $payload = SOAP::Data->name( 'persKeyParam' => '123456' );

my $info = $service->getEmpInfo( '', $payload );

print Data::Dumper->new( [$info], [qw/$info/] )->Indent(1)->Dump;

How come I have to use the following:

my $info = $service->getEmpInfo( '', $payload );

The examples found in the documentation always speak of:

my $info = $service->getEmpInfo( $payload );

The code just above returns a $info = undef;

I found out about the '' by accident :)

The http://the.webservice/service/pers?wsdl returns:

   <xs:complexType name='getEmpInfo'>
    <xs:sequence>
     <xs:element minOccurs='0' name='persKeyParam' type='xs:string'/>
    </xs:sequence>
   </xs:complexType>

and

  <operation name='getEmpInfo'>
   <soap:operation soapAction=''/>
   <input>
    <soap:body use='literal'/>
   </input>
   <output>
    <soap:body use='literal'/>
   </output>
  </operation>

Calling $service->getEmpInfo( $payload ); with debug on gives:

<?xml version="1.0" encoding="UTF-8"?>
<soap:Envelope soap:encodingStyle="http://schemas.xmlsoap.org/soap/enc
+oding/" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:
+soapenc="http://schemas.xmlsoap.org/soap/encoding/" xmlns:xsi="http:/
+/www.w3.org/2001/XMLSchema-instance" xmlns:tns="http://webservice.my.
+work/" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<soap:Body>
<tns:getEmpInfo>
<getEmpInfo xsi:nil="true" xsi:type="tns:getEmpInfo" />
</tns:getEmpInfo>
</soap:Body>
</soap:Envelope>

Calling $service->getEmpInfo( '', $payload ); with debug on gives:

<?xml version="1.0" encoding="UTF-8"?>
<soap:Envelope soap:encodingStyle="http://schemas.xmlsoap.org/soap/enc
+oding/" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:
+soapenc="http://schemas.xmlsoap.org/soap/encoding/" xmlns:xsi="http:/
+/www.w3.org/2001/XMLSchema-instance" xmlns:tns="http://webservice.my.
+work/" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<soap:Body>
<tns:getEmpInfo>
<getEmpInfo xsi:nil="true" xsi:type="tns:getEmpInfo" />
<persKeyParam xsi:type="xsd:int">
123456
</persKeyParam>
</tns:getEmpInfo>
</soap:Body>
</soap:Envelope>

The SOAP::Lite I'm using is 0.710.10

The extra '' parameter seems wrong. Why do I need to shift my persKeyParam up one index? What's going on?
For as long as $payload comes as a second parameter the call works. No matter what I put as a first param it works. I can put '' as an empty string, or a 0 or any other number.

Why does it work? If anyone could enlighten me I'd be grateful.


Greetings!

[Anonymous Monk]

Why does it work? If anyone could enlighten me I'd be grateful.

Because the SOAP server you're using decided it can do whatever it wants, even if it makes no sense