How do I validate xml against a DTD file in Python

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I need to validate an XML string (and not a file)
against a DTD description file.

How can that be done in python?

Another good option is lxml’s validation which I find quite pleasant to use.

A simple example taken from the lxml site:

from StringIO import StringIO

from lxml import etree

dtd = etree.DTD(StringIO("""<!ELEMENT foo EMPTY>"""))
root = etree.XML("<foo/>")
# True

root = etree.XML("<foo>bar</foo>")
# False
# <string>:1:0:ERROR:VALID:DTD_NOT_EMPTY: Element foo was declared EMPTY this one has content

from the examples directory in the libxml2 python bindings:

#!/usr/bin/python -u
import libxml2
import sys

# Memory debug specific

dtd="""<!ELEMENT foo EMPTY>"""
instance="""<?xml version="1.0"?>

dtd = libxml2.parseDTD(None, 'test.dtd')
ctxt = libxml2.newValidCtxt()
doc = libxml2.parseDoc(instance)
ret = doc.validateDtd(ctxt, dtd)
if ret != 1:
    print "error doing DTD validation"

del dtd
del ctxt

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