PyXB: Python XML Schema Bindings / Tickets / #119 pyxb.exceptions_.SchemaValidationError: QName AuthenticationRequest with absent default namespace cannot be resolved

Karl Putland - 2012-02-07

attachment _BW_OCISchema_Debug.tgz_ added

required schema and generated source
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Peter A. Bigot - 2012-02-07

status changed from new to closed

resolution set to invalid

PyXB is correct here.

AuthenticationRequest is defined in OCISchemaLogin.xsd, which has an absent namespace. It must be found within the context of bwas.Namespace.

When you create the document using the ocibase module, which contains material in namespace "C", there is no way for PyXB to know how to resolve symbols that are in an absent namespace, as there is no way (in XML) to associate those symbols with a namespace.

If, instead, you create the document with:

bd = bwas.CreateFromDocument(xmls)

so the fallback namespace to use when resolving symbols in an absent namespace is bwas.Namespace, things work as they should.

(Arguably, the definition of CreateFromDocument at the top of each module is wrong, since it provides a keyword argument default_namespace which if it wasn't ignored might have allowed you to do:

bd = ocibase.CreateFromDocument(xmls,default_namespace=bwas.Namespace)

However, some thought and testing of existing practice must be directed to whether this is the intent of that keyword, or whether it should be renamed to fallback_namespace, which is the keyword normally used for that function.)
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status changed from closed to reopened
resolution invalid deleted

So... the round trip works when using

>>> bd = bwas.CreateFromDocument(ocibase.BroadsoftDocument(sessionId="d3cafbad", protocol="OCI", command=[bwas.AuthenticationRequest(userId='someuserID')]).toxml())
>>> bd
<ocibase.OCIMessage object at 0x10124d590>
>>> bd.toxml()
u'<?xml version="1.0" ?><ns1:BroadsoftDocument protocol="OCI" xmlns:ns1="C" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><sessionId>d3cafbad</sessionId><command xsi:type="AuthenticationRequest"><userId>someuserID</userId></command></ns1:BroadsoftDocument>'

But when starting the conversation with Broadsoft it fails when using bwas.CreateFromDocument

>>> ar = ocibase.BroadsoftDocument(sessionId="d3cafbad", protocol="OCI", command=[bwas.AuthenticationRequest(userId='ociuser')])
>>> s.sendall(ar.toxml())
>>> res = s.recv(4096)
>>> res
'<?xml version="1.0" encoding="UTF-8"?>\n<BroadsoftDocument protocol="OCI" xmlns="C" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><sessionId xmlns="">d3cafbad</sessionId><command echo="" xsi:type="AuthenticationResponse" xmlns=""><userId>ociuser</userId><nonce>1328660896121</nonce><passwordAlgorithm>MD5</passwordAlgorithm></command></BroadsoftDocument>\n'

>>> bd = bwas.CreateFromDocument(res)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "bwas.py", line 33, in CreateFromDocument
    saxer.parse(StringIO.StringIO(xml_text))
  File "/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/xml/sax/expatreader.py", line 107, in parse
    xmlreader.IncrementalParser.parse(self, source)
  File "/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/xml/sax/xmlreader.py", line 123, in parse
    self.feed(buffer)
  File "/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/xml/sax/expatreader.py", line 207, in feed
    self._parser.Parse(data, isFinal)
  File "/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/xml/sax/expatreader.py", line 338, in start_element_ns
    AttributesNSImpl(newattrs, qnames))
  File "/Library/Python/2.6/site-packages/PyXB-1.1.3-py2.6.egg/pyxb/binding/saxer.py", line 329, in startElementNS
    (did_replace, type_class) = XSI._InterpretTypeAttribute(attrs.getValue(self.__XSITypeTuple), ns_ctx, None, type_class)
  File "/Library/Python/2.6/site-packages/PyXB-1.1.3-py2.6.egg/pyxb/namespace/builtin.py", line 103, in _InterpretTypeAttribute
    type_en = ns_ctx.interpretQName(type_name, namespace=fallback_namespace)
  File "/Library/Python/2.6/site-packages/PyXB-1.1.3-py2.6.egg/pyxb/namespace/resolution.py", line 611, in interpretQName
    raise pyxb.SchemaValidationError('QName %s with absent default namespace cannot be resolved' % (local_name,))
pyxb.exceptions_.SchemaValidationError: QName AuthenticationResponse with absent default namespace cannot be resolved

>>> 'AuthenticationResponse' in dir(bwas) 
True

AuthenticationResponse returned from server

'<?xml version="1.0" encoding="UTF-8"?>\n<BroadsoftDocument protocol="OCI" xmlns="C" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><sessionId xmlns="">d3cafbad</sessionId><command echo="" xsi:type="AuthenticationResponse" xmlns=""><userId>ociuser</userId><nonce>1328660896121</nonce><passwordAlgorithm>MD5</passwordAlgorithm></command></BroadsoftDocument>\n'

Where am I going wrong with this?

Peter A. Bigot - 2012-02-08

status changed from reopened to accepted

You're not going wrong. Here the issue is that the outermost element defines a default namespace "C", which discards the normal fallback. PyXB is not interpreting the internal set of an empty default namespace as being the fallback namespace; probably because that deep inside processing it doesn't know which absent namespace to select.

I expect this will turn out to be a PyXB issue, but I'll have to dig into this tomorrow.
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Peter A. Bigot - 2012-02-08

attachment _trac0119.patch_ added

patch for trac #119
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Peter A. Bigot - 2012-02-08

status changed from accepted to closed

resolution set to fixed

Fixed in the trac0119.patch attachment and pushed to the next branch for the next release. (You do still have to use the module corresponding to the absent namespace to do the parsing.)
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Verified initial test succeeds!
Thank you!

>>> s = socket.socket()
>>> s.connect((socket.gethostbyname('hostname'),2208))
>>> import ocibase, bwas
>>> ar = ocibase.BroadsoftDocument(sessionId="d3cafbad", protocol="OCI", command=[bwas.AuthenticationRequest(userId='ocitest!')])
>>> s.sendall(ar.toxml())
>>> res = s.recv(4096)
>>> bd = bwas.CreateFromDocument(res)
>>> bd
<ocibase.OCIMessage object at 0x101d12c90>
>>> bd.toxml()
u'<?xml version="1.0" ?><ns1:BroadsoftDocument protocol="OCI" xmlns:ns1="C" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><sessionId>d3cafbad</sessionId><command echo="" xsi:type="AuthenticationResponse"><userId>ocitest!</userId><nonce>1328721149827</nonce><passwordAlgorithm>MD5</passwordAlgorithm></command></ns1:BroadsoftDocument>'
>>> bd.command
[<bwas.AuthenticationResponse object at 0x101d7c890>]
>>>

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#119 pyxb.exceptions_.SchemaValidationError: QName AuthenticationRequest with absent default namespace cannot be resolved

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