Force xsi:type to appear on request element

[ale-rinaldi]

Hello,

I'm integrating with a service whose WSDL is unfortunately private, but it's similar to this toy version (input parameters are intentionally over-complicated here to match the real scenario):

• service.wsdl:

<?xml version="1.0" encoding="UTF-8"?>
<wsdl:definitions xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/"
	xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/" xmlns:xs="http://www.w3.org/2001/XMLSchema"
	xmlns:mysvc="http://www.example.org/schemas/mysvc"
	xmlns:mycalc="http://www.example.org/schemas/mycalc"
	targetNamespace="http://www.example.org/schemas/mysvc">


	<wsdl:types>
		<xs:schema xmlns="http://www.w3.org/2001/XMLSchema">
			<xs:import namespace="http://www.example.org/schemas/mycalc"
				schemaLocation="schema.xsd"/>
		</xs:schema>
	</wsdl:types>

	
	<!-- *** Messages *** -->
	
	<wsdl:message name="sumRequest">
		<wsdl:part name="SumParameters" type="mycalc:sumParametersType"/>
	</wsdl:message>

	<wsdl:message name="sumResponse">
		<wsdl:part name="SumResult" type="xs:int"/>
	</wsdl:message>

	<!-- *** PortTypes *** -->

	<wsdl:portType name="Calculator">
		<wsdl:operation name="sum">
			<wsdl:input message="mysvc:sumRequest"/>
			<wsdl:output message="mysvc:sumResponse"/>
		</wsdl:operation>
	</wsdl:portType>


	<!-- *** Bindings *** -->

	<wsdl:binding name="CalculatorBinding" type="mysvc:Calculator">

		<soap:binding style="rpc" transport="http://schemas.xmlsoap.org/soap/http"/>

		<wsdl:operation name="sum">
			<soap:operation soapAction="sum"/>
			<wsdl:input>
				<soap:body
					namespace="http://www.example.org/schemas/mycalc"
					parts="SumParameters" use="literal"/>
			</wsdl:input>
			<wsdl:output>
				<soap:body
					namespace="http://www.example.org/schemas/mycalc"
					parts="SumResult" use="literal"/>
			</wsdl:output>
		</wsdl:operation>
	</wsdl:binding>


	<!-- *** Services *** -->

	<wsdl:service name="CalculatorService">
		<wsdl:port name="CalculatorPort" binding="mysvc:CalculatorBinding">
			<soap:address location="http://localhost:8080/myservice"/>
		</wsdl:port>
	</wsdl:service>

</wsdl:definitions>

• schema.xsd

<?xml version="1.0" encoding="UTF-8"?>
<schema xmlns="http://www.w3.org/2001/XMLSchema"
    xmlns:mycalc="http://www.example.org/schemas/mycalc"
    elementFormDefault="qualified"
    targetNamespace="http://www.example.org/schemas/mycalc">
    
    <complexType name="sumParametersType">
        <complexContent>
            <restriction base="mycalc:sumParametersType">
                <sequence>
                    <element name="NumbersToAdd" type="mycalc:numbersToAddType" minOccurs="1" maxOccurs="1"/>
                </sequence>
            </restriction>
        </complexContent>
    </complexType>
    <complexType name="numbersToAddType">
        <complexContent>
            <restriction base="mycalc:numbersToAddType">
                <sequence>
                    <element name="NumA" type="int" minOccurs="1" maxOccurs="1"/>
                    <element name="NumB" type="int" minOccurs="1" maxOccurs="1"/>
                </sequence>
            </restriction>
        </complexContent>
    </complexType>
</schema>

• Code I'm running:

from zeep import Client
from lxml import etree

client = Client("wsdl/service.wsdl")

client.set_ns_prefix("mycalc", "http://www.example.org/schemas/mycalc")

mycalc = client.type_factory("mycalc")

request = mycalc.sumParametersType(
    NumbersToAdd=mycalc.numbersToAddType(
        NumA=10,
        NumB=20,
    )
)

message = client.create_message(client.service, "sum", request)
print(etree.tostring(message, pretty_print=True).decode())

This would generate the following request:

<soap-env:Envelope xmlns:soap-env="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:mycalc="http://www.example.org/schemas/mycalc">
  <soap-env:Body>
    <mycalc:sum>
      <SumParameters>
        <mycalc:NumbersToAdd>
          <mycalc:NumA>10</mycalc:NumA>
          <mycalc:NumB>20</mycalc:NumB>
        </mycalc:NumbersToAdd>
      </SumParameters>
    </mycalc:sum>
  </soap-env:Body>
</soap-env:Envelope>

The service will complain because SumParameters is missing the "xsi:type" attribute. In fact, if I change the request like this:

<soap-env:Envelope xmlns:soap-env="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:mycalc="http://www.example.org/schemas/mycalc">
  <soap-env:Body>
    <mycalc:sum>
      <SumParameters xsi:type="mycalc:sumParametersType">
        <mycalc:NumbersToAdd>
          <mycalc:NumA>10</mycalc:NumA>
          <mycalc:NumB>20</mycalc:NumB>
        </mycalc:NumbersToAdd>
      </SumParameters>
    </mycalc:sum>
  </soap-env:Body>
</soap-env:Envelope>

then it's correctly accepted.

Is there a way to force the presence of the xsi:type parameter?

Thank you