How can I make Python's ElementTree enforce XML schema?

Question

Suppose I wish to parse an XML document, and its schema dictates that a given element can only occur once.

How do I make sure that an exception gets raised if the element occurs twice or more?

Or, if the schema says that a given element's value should be an integer, and the value is "turkey sandwich", how do I make the parser crash and burn like it's supposed to?

Can ElementTree do this? Can anything do this? Does this question even make sense?

please provide sample data and expected output. so that it will be easy to slve — sundar nataraj, Jul 14 '14 at 03:09
The parser doesn't have any buit in checker for this. You will have to manually check the elements. Maintain some counter — user2963623, Jul 14 '14 at 03:12
With `lxml` you can: http://stackoverflow.com/questions/17819884/xml-xsd-feed-validation-against-a-schema/17819981#17819981 — alecxe, Jul 14 '14 at 03:26

Antoine · Accepted Answer · 2020-10-08T09:20:32.093

ElementTree from the STD lib has not schema support. For this, I suggest you to use the lxml package which has it (and by the way, it's much faster).

Here after an example from my own code:

from lxml import etree

# Create the schema object
with open(xsd_file) as f:
    xmlschema_doc = etree.parse(f)
xmlschema = etree.XMLSchema(xmlschema_doc)
    
# Create a tree for the XML document
doc = etree.parse(xml_text)

# Validate the XML document using the schema
return xmlschema.validate(doc)

or if you want a exception to be raised:

xmlschema.assertValid(doc)

How can I make Python's ElementTree enforce XML schema?

1 Answers1