Issue1268

The following patch prevents SAX from loading external DTDs. These
caused Jython to crash when parsing XML documents with Doctypes (such as
XHTML or SVG).

Included is a simple testcase that fails in the latest SVN versions.
Applying the patch fixes the error. The following error is displayed:

Traceback (most recent call last):
  File "test_parseString.py", line 6, in <module>
    xml = parseString(data)
  File "/Users/fdb/Java/jython-svn/dist/Lib/xml/dom/minidom.py", line
1933, in parseString
    return _do_pulldom_parse(pulldom.parseString, (string,),
  File "/Users/fdb/Java/jython-svn/dist/Lib/xml/dom/minidom.py", line
1908, in _do_pulldom_parse
    toktype, rootNode = events.getEvent()
  File "/Users/fdb/Java/jython-svn/dist/Lib/xml/dom/pulldom.py", line
275, in _slurp
    self.parser.parse(self.stream)
  File
"/Users/fdb/Java/jython-svn/dist/Lib/xml/sax/drivers2/drv_javasax.py",
line 143, in parse
    self._parser.parse(JyInputSourceWrapper(source))
  File
"/Users/fdb/Java/jython-svn/dist/Lib/xml/sax/drivers2/drv_javasax.py",
line 92, in resolveEntity
    return JyInputSourceWrapper(self._resolver.resolveEntity(pubId, sysId))
  File
"/Users/fdb/Java/jython-svn/dist/Lib/xml/sax/drivers2/drv_javasax.py",
line 77, in __init__
    if source.getByteStream():
AttributeError: 'unicode' object has no attribute 'getByteStream'

The original patch contained an oversight where the actual changed line
was commented out for testing purposes. The new patch fixes the problem.

I have come across the same bug when trying to actually use the external
DTD functionality. After attaching following line into my XML file:

<!DOCTYPE common SYSTEM "common.dtd">

I got the error mentioned by Frederik. Luckily there is an easy fix for
this issue. Following line in JyInputSourceWrapper needs to be changed from:
        if isinstance(source, str):
            javasax.InputSource.__init__(self, source)
to:
        if isinstance(source, str) or isinstance(source, unicode):
            javasax.InputSource.__init__(self, source)

After Lukasz Heldt fix i get (i dont get this on cpython):

java.io.FileNotFoundException: java.io.FileNotFoundException:
C:\sysdef_1_4_0.dtd (The system can
not find the file specified)

I added the patch and its ok do-not-load-external-dtds.patch.txt

Turning off DTD validation seems the cleanest solution and is conform
with the Python parsing API, which does not validate external DTDs.