python suds wrong namespace prefix in SOAP request

Question

I use python/suds to implement a client and I get wrong namespace prefixes in the sent SOAP header for a spefic type of parameters defined by element ref= in the wsdl.

The .wsdl is referencing a data types .xsd file, see below. The issue is with the function GetRecordAttributes and its first argument of type gbt:recordReferences.

File: browse2.wsdl

<xsd:schema targetNamespace="http://www.grantadesign.com/10/10/Browse" xmlns="http://www.grantadesign.com/10/10/Browse" xmlns:gbt="http://www.grantadesign.com/10/10/GrantaBaseTypes" elementFormDefault="qualified" attributeFormDefault="qualified">
<xsd:import schemaLocation="grantabasetypes2.xsd" namespace="http://www.grantadesign.com/10/10/GrantaBaseTypes"/>
<xsd:element name="GetRecordAttributes">
      <xsd:complexType>
          <xsd:sequence>
              <xsd:element ref="gbt:recordReferences">
              </xsd:element>

Referenced File : grantabasetypes2.xsd

<element name="recordReferences">
  <complexType>
    <sequence>
      <element name="record" minOccurs="0" maxOccurs="unbounded" type="gbt:MIRecordReference"/>
    </sequence>
  </complexType>
</element>

SOAP Request sent by suds:

<SOAP-ENV:Envelope xmlns:ns0="http://www.grantadesign.com/10/10/GrantaBaseTypes" xmlns:ns1="http://schemas.xmlsoap.org/soap/envelope/" xmlns:ns2="http://www.grantadesign.com/10/10/Browse" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
   <SOAP-ENV:Header/>
   <ns1:Body>
      <ns2:GetRecordAttributes>
         <ns2:recordReferences>
            <ns0:record>
            </ns0:record>
         </ns2:recordReferences>
      </ns2:GetRecordAttributes>
   </ns1:Body>
</SOAP-ENV:Envelope>

Problem : <ns2:recordReferences> has wrong prefix, should be <ns0:recordReferences> since it belongs to the namespace ...GrantaBaseTypes defined in the .xsd.

This happens for all arguments defined by ref= in the wsdl. How can this be automatically fixed?

Note: I checked that the "good" prefix is accepted by the service by manually sending the xml SOAP request via curl.

UPDATE

I meddled with SUDS source code and the following empirical fix forces all elements with ref= attribute to assume the ref-ed namespace (previously, they take on the schema root namespace or whatever tns is):

File: /suds/xsd/sxbase.py

class SchemaObject(object):
....
    def namespace(self, prefix=None):

        ns = self.schema.tns

#FIX BEGIN
        if self.ref and self.ref in self.schema.elements.keys():
            ns = self.ref
#FIX END

Works with my service, but I'm not sure if it'll break other things. I would prefer a smarter solution that does not change SUDS source code.

Thanks,

Alex

Answer 1

Write a Suds plugin to modify the XML before it is sent.

from suds.client import Client
from suds.plugin import MessagePlugin

class MyPlugin(MessagePlugin):
    def marshalled(self, context):
        #modify this line to reliably find the "recordReferences" element
        context.envelope[1][0][0].setPrefix('ns0')

client = Client(WSDL_URL, plugins=[MyPlugin()])

Quoting Suds documentation:

marshalled()
Provides the plugin with the opportunity to inspect/modify the envelope Document before it is sent.