Parsing XML using PYXB. Can't get to nested anonymous elements

Question

I've created Python bindings using PYXB(pyxbgen) on the following xsd files using the commands:

pyxbgen -u Event.xsd -m Event
pyxbgen -u Shape.xsd -m Shape
pyxbgen -u flow-tags.xsd -m flow-tags

Using the generated bindings, I can access all the "event" data but I can't see how to access the "detail" elements and data. Specifically, the ellipse and polygon (with vertex data) from the shape element. The detail element is an anonymous type. Here is the code I have thus far:

    import Shape, Event, flow-tags

    xml = '''
    <event how="h-p" opex="e-TEST" qos="7-r-g" stale="2014-04-21T20:50:01.85Z" start="2014-04-21T20:48:01.85Z" time="2014-04-21T20:48:01.85Z" type="a-n-A-M-F-R-Z" uid="6716" version="2.0"><detail><_flow-tags_ debug="2014-04-21T20:48:01.00Z" /><shape><ellipse angle="33" major="44" minor="22" /><polyline closed="1"><vertex hae="1" lat="44" lon="-77" /></polyline></shape></detail><point ce="122.8" hae="817.2" lat="42.5612194" le="431.3" lon="-71.302077" /></event>
    '''

    event = Event.CreateFromDocument(xml)
    print event.uid
    print event.point.lon

    detail = event.detail
    #not sure what goes after this to get content of detail data?????

Here are the Event.xsd and Shape.xsd files I am using. They are not mine so I don't have the option to modify them if there is a problem with them.

Event.xsd:

 <?xml version="1.0" encoding="UTF-8"?>

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
    elementFormDefault="qualified">
    <xs:element name="event">
        <xs:annotation>
            <xs:documentation>Event Definition</xs:documentation>
        </xs:annotation>
        <xs:complexType>
        <xs:all>
            <xs:element ref="point" />
            <xs:element ref="detail" minOccurs="0" />
        </xs:all>
        <xs:attribute name="version" use="required">
            <xs:simpleType>
                <xs:restriction base="xs:decimal">
                    <xs:minInclusive value="2" />
                </xs:restriction>
            </xs:simpleType>
        </xs:attribute>
        <xs:attribute name="type" use="required">
            <xs:annotation>
                <xs:documentation>
                    The "type" attribute
                </xs:documentation>
            </xs:annotation>
            <xs:simpleType>
                <xs:restriction base="xs:string">
                    <xs:pattern value="\w+(-\w+)*(;[^;]*)?" />
                </xs:restriction>
            </xs:simpleType>
        </xs:attribute>
        <xs:attribute name="access" type="xs:string" use="optional">
            <xs:annotation>
                <xs:documentation>
                    The access field
                </xs:documentation>
            </xs:annotation>
        </xs:attribute>
        <xs:attribute name="qos" use="optional">
            <xs:annotation>
                <xs:documentation>
                    format - digit-character-character
                </xs:documentation>
            </xs:annotation>
            <xs:simpleType>
                <xs:restriction base="xs:string">
                    <xs:pattern value="\d-\w-\w" />
                </xs:restriction>
            </xs:simpleType>
        </xs:attribute>
        <xs:attribute name="opex" type="xs:string" use="optional">
            <xs:annotation>
                <xs:documentation>
                    The opex field
                </xs:documentation>
            </xs:annotation>
        </xs:attribute>
        <xs:attribute name="uid" type="xs:string" use="required">
            <xs:annotation>
                <xs:documentation>
                    The "uid" attribute
                </xs:documentation>
            </xs:annotation>
        </xs:attribute>
        <xs:attribute name="time" type="xs:dateTime" use="required">
            <xs:annotation>
                <xs:documentation>
                    The XML schema includes three time values:
                </xs:documentation>
            </xs:annotation>
        </xs:attribute>
        <xs:attribute name="start" type="xs:dateTime" use="required">
            <xs:annotation>
                <xs:documentation>
                    format - DTG
                </xs:documentation>
            </xs:annotation>
        </xs:attribute>
        <xs:attribute name="stale" type="xs:dateTime" use="required">
            <xs:annotation>
                <xs:documentation>
                    The "stale" attribute
                </xs:documentation>
            </xs:annotation>
        </xs:attribute>
        <xs:attribute name="how" use="required">
            <xs:annotation>
                <xs:documentation>
                    format = character-character
                </xs:documentation>
            </xs:annotation>
            <xs:simpleType>
                <xs:restriction base="xs:string">
                    <xs:pattern value="\w(-\w+)*" />
                </xs:restriction>
            </xs:simpleType>
        </xs:attribute>
    </xs:complexType>
</xs:element>
<xs:element name="detail">
    <xs:annotation>
        <xs:documentation>
            format
        </xs:documentation>
    </xs:annotation>
    <xs:complexType>
        <xs:sequence>
            <xs:any processContents="lax" minOccurs="0" maxOccurs="unbounded" />
        </xs:sequence>
        <xs:anyAttribute processContents="skip" />
    </xs:complexType>
</xs:element>
<xs:element name="point">
    <xs:complexType>
        <xs:attribute name="lat" use="required">
            <xs:annotation>
                <xs:documentation>Latitude based on WGS-84 ellipsoid in signed
                    degree-decimal format (e.g. -33.350000). Range -90 -> +90.
                </xs:documentation>
            </xs:annotation>
            <xs:simpleType>
                <xs:restriction base="xs:decimal">
                    <xs:minInclusive value="-90" />
                    <xs:maxInclusive value="90" />
                </xs:restriction>
            </xs:simpleType>
        </xs:attribute>
        <xs:attribute name="lon" use="required">
            <xs:annotation>
                <xs:documentation>Longitude based on WGS-84 ellipsoid in signed
                    degree-decimal format (e.g. 44.383333). Range -180 -> +180.
                </xs:documentation>
            </xs:annotation>
            <xs:simpleType>
                <xs:restriction base="xs:decimal">
                    <xs:minInclusive value="-180" />
                    <xs:maxInclusive value="180" />
                </xs:restriction>
            </xs:simpleType>
        </xs:attribute>
        <xs:attribute name="hae" type="xs:decimal" use="required">
            <xs:annotation>
                <xs:documentation>HAE acronym for Height above Ellipsoid based on
                    WGS-84 ellipsoid (measured in meters).
                </xs:documentation>
            </xs:annotation>
        </xs:attribute>
        <xs:attribute name="ce" type="xs:decimal" use="required">
            <xs:annotation>
                <xs:documentation>
                    Circular Error
                </xs:documentation>
            </xs:annotation>
        </xs:attribute>
        <xs:attribute name="le" type="xs:decimal" use="required">
            <xs:annotation>
                <xs:documentation>
                    Linear Error
                </xs:documentation>
            </xs:annotation>
        </xs:attribute>
    </xs:complexType>
</xs:element>

Shape.xsd:

<?xml version="1.0" encoding="UTF-8"?>

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.w3.org/2001/XMLSchema      http://www.w3.org/2001/XMLSchema.xsd"
elementFormDefault="qualified" attributeFormDefault="unqualified">
<xs:simpleType name="nonNegativeDecimal">
    <xs:restriction base="xs:decimal">
        <xs:minInclusive value="0" />
    </xs:restriction>
    <!-- Defined as global type for XML Gallery manifest reference than 
        any other reason -->
</xs:simpleType>
<xs:element name="shape">
    <xs:annotation>
        <xs:documentation></xs:documentation>
    </xs:annotation>
    <xs:complexType>
        <xs:sequence>
            <xs:element name="ellipse" minOccurs="0">
                <xs:annotation>
                    <xs:documentation>The "ellipse" is a common shape abstraction used
                        by many geomanipulation applications; it is supported natively.
                    </xs:documentation>
                </xs:annotation>
                <xs:complexType>
                    <xs:sequence>
                        <xs:any processContents="lax" minOccurs="0" maxOccurs="unbounded" />
                    </xs:sequence>
                    <xs:attribute name="major" type="nonNegativeDecimal"
                        use="required">
                        <xs:annotation>
                            <xs:documentation>Ellipse major axis (meters)</xs:documentation>
                        </xs:annotation>
                    </xs:attribute>
                    <xs:attribute name="minor" type="nonNegativeDecimal"
                        use="required">
                        <xs:annotation>
                            <xs:documentation>Ellipse minor axis (meters)</xs:documentation>
                        </xs:annotation>
                    </xs:attribute>
                    <xs:attribute name="angle" type="xs:decimal" use="required">
                        <xs:annotation>
                            <xs:documentation>Orientation of major axis with respect to true
                                north.
                            </xs:documentation>
                        </xs:annotation>
                    </xs:attribute>
                    <xs:attribute name="level" type="xs:integer" use="optional">
                        <xs:annotation>
                            <xs:documentation>"level"
                            </xs:documentation>
                        </xs:annotation>
                    </xs:attribute>
                    <xs:attribute name="extrude" type="xs:nonNegativeInteger"
                        use="optional">
                        <xs:annotation>
                            <xs:documentation>A "Height" of the ellipse used to make the
                                flat object encompas a volume.
                            </xs:documentation>
                        </xs:annotation>
                    </xs:attribute>
                </xs:complexType>
            </xs:element>
            <xs:element name="polyline" minOccurs="0">
                <xs:annotation>
                    <xs:documentation>The poly line provides a mechanism to express
                        arbitrarily complex two-dimenstional shapes.
                    </xs:documentation>
                </xs:annotation>
                <xs:complexType>
                    <xs:sequence>
                        <xs:element name="vertex" minOccurs="2" maxOccurs="unbounded">
                            <xs:complexType>
                                <xs:attribute name="lat" use="required">
                                    <xs:annotation>
                                        <xs:documentation>Latitude based on WGS-84 ellipsoid in
                                            signed degree-decimal format (e.g. -33.350000). Range -90 ->
                                            +90. Positive values denote north.
                                        </xs:documentation>
                                    </xs:annotation>
                                    <xs:simpleType>
                                        <xs:restriction base="xs:decimal">
                                            <xs:minInclusive value="-90" />
                                            <xs:maxInclusive value="90" />
                                        </xs:restriction>
                                    </xs:simpleType>
                                </xs:attribute>
                                <xs:attribute name="lon" use="required">
                                    <xs:annotation>
                                        <xs:documentation>Longitude based on WGS-84 ellipsoid in
                                            signed degree-decimal format (e.g. 44.383333). Range -180 ->
                                            +180. Positive values denote east.
                                        </xs:documentation>
                                    </xs:annotation>
                                    <xs:simpleType>
                                        <xs:restriction base="xs:decimal">
                                            <xs:minInclusive value="-180" />
                                            <xs:maxInclusive value="180" />
                                        </xs:restriction>
                                    </xs:simpleType>
                                </xs:attribute>
                                <xs:attribute name="hae" type="xs:decimal" use="optional">
                                    <xs:annotation>
                                        <xs:documentation>Height Above Ellipsoid (HAE) in Meters.
                                        </xs:documentation>
                                    </xs:annotation>
                                </xs:attribute>
                            </xs:complexType>
                        </xs:element>
                        <xs:any processContents="lax" minOccurs="0" maxOccurs="unbounded" />
                    </xs:sequence>
                    <xs:attribute name="level" type="xs:integer">
                        <xs:annotation>
                            <xs:documentation>"level"
                            </xs:documentation>
                        </xs:annotation>
                    </xs:attribute>
                    <xs:attribute name="closed" type="xs:boolean"
                        default="true">
                        <xs:annotation>
                            <xs:documentation>True if the list of verticies should be
                                considered a closed polygon (an implicit line will be added
                                from vertex N to vertex 0).
                            </xs:documentation>
                        </xs:annotation>
                    </xs:attribute>
                </xs:complexType>
            </xs:element>
            <xs:element name="dxf" minOccurs="0">
                <xs:annotation>
                    <xs:documentation>This is a hook for an arbitrary 3D DXF
                        description of a volume of space.
                    </xs:documentation>
                </xs:annotation>
                <xs:complexType>
                    <xs:sequence>
                        <xs:any processContents="lax" minOccurs="0" maxOccurs="unbounded" />
                    </xs:sequence>
                    <xs:attribute name="level" type="xs:integer">
                        <xs:annotation>
                            <xs:documentation>"level"  </xs:documentation>
                        </xs:annotation>
                    </xs:attribute>
                </xs:complexType>
            </xs:element>
        </xs:sequence>
        <xs:attribute name="version" type="xs:decimal" use="optional">
            <xs:annotation>
                <xs:documentation>Version tag for this sub schema. Can be used to
                    ensure upward compatibility with future revisions.
                </xs:documentation>
            </xs:annotation>
        </xs:attribute>
    </xs:complexType>
</xs:element>

flow-tags.xsd:

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.w3.org/2001/XMLSchema http://www.w3.org/2001/XMLSchema.xsd"
elementFormDefault="qualified" attributeFormDefault="unqualified">
<xs:element name="_flow-tags_">
    <xs:annotation>
        <xs:documentation>This is a detail sub-schema</xs:documentation>
    </xs:annotation>
    <xs:complexType>
        <xs:sequence>
            <xs:any processContents="lax" minOccurs="0" maxOccurs="unbounded" />
        </xs:sequence>
        <xs:attribute name="version" type="xs:decimal" use="optional" />
        <xs:anyAttribute processContents="lax">
            <xs:annotation>
                <xs:documentation>A system-specific flowtag identifier.
                </xs:documentation>
            </xs:annotation>
        </xs:anyAttribute>
    </xs:complexType>
</xs:element>

Thanks in advance for any help!

Answer 1

The element children of details that are not recognized get added as wildcards, and can be accessed this way:

detail = event.detail
for elt in detail.wildcardElements():
    print elt

However, those elements are both DOM instances (one for _flow-tags_, one for shape). Normally PyXB will convert elements for any bindings that have been loaded into the application, though they'll still be stored in the wildcardElements() array. That's not happening here because the two schemas you're using both have absent namespaces, but are being translated as independent schema. There is no element _flow-tags_ in either schema, but the shape is not being converted to a binding because the elements from the Shape schema cannot be recognized within the absent namespace used for Event.

Not knowing where those schema came from I can't tell how they're supposed to be used, but one approach would be to combine them into a parent schema as in:

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    elementFormDefault="qualified" attributeFormDefault="unqualified">
<xs:include schemaLocation="Shape.xsd"/>
<xs:include schemaLocation="Event.xsd"/>
</xs:schema>

Then build bindings from this:

pyxbgen -u combine.xsd -m combine

Then you can import those bindings, which have both Event and Shape components, thusly:

import pyxb
import combine

xml = '''
<event how="h-p" opex="e-TEST" qos="7-r-g" stale="2014-04-21T20:50:01.85Z" start="2014-04-21T20:48:01.85Z" time="2014-04-21T20:48:01.85Z" type="a-n-A-M-F-R-Z" uid="6716" version="2.0"><detail><_flow-tags_ debug="2014-04-21T20:48:01.00Z" /><shape><ellipse angle="33" major="44" minor="22" /><polyline closed="1"><vertex hae="1" lat="44" lon="-77" /></polyline></shape></detail><point ce="122.8" hae="817.2" lat="42.5612194" le="431.3" lon="-71.302077" /></event>
'''

try:
    event = combine.CreateFromDocument(xml)
except pyxb.IncompleteElementContentError as ex:
    print ex.details()

You'll see that the example document is not valid because of the following error:

The containing element polyline is defined at Shape.xsd[65:12].
The containing element type <class 'combine.CTD_ANON_2'> is defined at Shape.xsd[71:16]
The <class 'combine.CTD_ANON_2'> automaton is not in an accepting state.
Any accepted content has been stored in instance
The following element and wildcard content would be accepted:
        An element vertex per Shape.xsd[73:24]
No content remains unconsumed

If you look at Shape.xsd line 73 you'll see that a polyline requires at least two vertex elements. If you then correct the document to have a second vertex, then the first member of details.wildcardElements() will still be a DOM Element instance, but the second will be a shape binding.