如何使用属性从 XSD 中创建 Python 对象

Question

I am working on a project that is meant to take many different data sources and place them in a data table. To do this, we have a way to import the data through an XML document that has all of the fields defined in the table. A few of these fields are required. Fields that are required have a minimum occurrences value of a non-zero positive integer.

I have the XSD files for these XML documents. This isn't a 1 to 1 copy (since it's proprietary), but here is an example:

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified"   attributeFormDefault="unqualified">
    <xs:element name="Widget">
        <xs:complexType>
            <xs:all>
                <xs:element name="GuyWhoMadeWidget" nillable="true" minOccurs="1">
            </xs:all>
            <xs:attribute name="version" type="xs:string"/>
        <xs:complexType>
    </xs:element>
 </xs:schema>

What I want to be able to do is go into the <xs: element> element and do logic in Python on whether or not minOccurs is a non-zero value. Here's some pseudocode:

file_object = open(xsd_file)
required_fields = []
xsd_python_object = parse_xsd_to_python(file_object)
for element in xsd_python_object:
    if element.minOccurs != 0:
         required_fields.append(element.name)
print(required_fields)

Sample output here would be:

Required fields for "Widget" table:
GuyWhoMadeWidget

I have been looking into the xmlschema and lxml packages but their facilities leave me wanting, confused, or both.

Answer 1

I had a project where I needed to iterate a XSD file and I used the xmlschema library using something similar to this code:

import xmlschema
schema = xmlschema.XMLSchema('your xsd file')

for xsd_component in schema.iter_components():
    if 'Element' in xsd_component:
        element_name = xsd_component.name

For example, printing the xsd_component would result in "XsdElement(name='sensor1value', occurs=[1, 1])" where I would use .split() function to retrieve the information that I needed. The if is a example of what you could do. The documentation doesn't show everything you can use so check the other functions if you need something specific.