I have written a small function, which uses ElementTree and xpath to extract the text contents of certain elements in an xml file:
#!/usr/bin/env python2.5
import doctest
from xml.etree import ElementTree
from StringIO import StringIO
def parse_xml_etree(sin, xpath):
"""
Takes as input a stream containing XML and an XPath expression.
Applies the XPath expression to the XML and returns a generator
yielding the text contents of each element returned.
>>> parse_xml_etree(
... StringIO('<test><elem1>one</elem1><elem2>two</elem2></test>'),
... '//elem1').next()
'one'
>>> parse_xml_etree(
... StringIO('<test><elem1>one</elem1><elem2>two</elem2></test>'),
... '//elem2').next()
'two'
>>> parse_xml_etree(
... StringIO('<test><null>�</null><elem3>three</elem3></test>'),
... '//elem2').next()
'three'
"""
tree = ElementTree.parse(sin)
for element in tree.findall(xpath):
yield element.text
if __name__ == '__main__':
doctest.testmod(verbose=True)
The third test fails with the following exception:
ExpatError: reference to invalid character number: line 1, column 13
Is the �
entity illegal XML? Regardless whether it is or not, the files I want to parse contain it, and I need some way to parse them. Any suggestions for another parser than Expat, or settings for Expat, that would allow me to do that?
Update: I discovered BeautifulSoup just now, a tag soup parser as noted below in the answer comment, and for fun I went back to this problem and tried to use it as an XML-cleaner in front of ElementTree, but it dutifully converted the �
into a just-as-invalid null byte. :-)
cleaned_s = StringIO(
BeautifulStoneSoup('<test><null>�</null><elem3>three</elem3></test>',
convertEntities=BeautifulStoneSoup.XML_ENTITIES
).renderContents()
)
tree = ElementTree.parse(cleaned_s)
... yields
xml.parsers.expat.ExpatError: not well-formed (invalid token): line 1, column 12
In my particular case though, I didn't really need the XPath parsing as such, I could have gone with BeautifulSoup itself and its quite simple node adressing style parsed_tree.test.elem1.contents[0]
.