Limited XML tidy

[Toby White]

I have a program which produces well-formed XML documents,
but takes several hours if not days to do so. It would
be useful to be able to take the incomplete output and
manipulate it as XML.

Clearly, however, the incomplete output will not be well-
formed, so before being able to manipulate it I need to
make it wellformed.

This is essentially fairly simple. I know it's well-formed
up to now - all I need to do is close unclosed tags. So,
I 've made a short function that will do this:

#!/usr/bin/python

import sys
import xml.sax

tagStack = []
closingTags = ""

class DodgyHandler(xml.sax.ContentHandler):
def startElement(self, tag, attributes):
tagStack.append(tag)

def endElement(self, tag):
tagStack.pop()


class DodgyErrorHandler(xml.sax.ErrorHandler):
def fatalError(self,exception):
global closingTags
tagStack.reverse()
for tag in tagStack:
closingTags += "</%s>" % tag
return closingTags

filename = sys.argv[1]

p = xml.sax.make_parser()
p.setContentHandler(DodgyHandler())
p.setErrorHandler(DodgyErrorHandler())

f = open(filename, mode='r')

for line in f:
print line,
p.feed(line)
p.close()

print closingTags

However - while this works for 90% of the cases I need,
it fails in the case where my incomplete output stops in the
middle of a tag (not to mention some other more arcane
places I don't really care about).

The problem is that when the sax handler raises an exception,
I can't see how to find out why. What I want to do is for
DodgyErrorHandler to do something different depending on
where we are in the course of parsing. Is there anyway
to get that information back from xml.sax (or indeed from
any other sax handler?)

Toby