This bug appears in httplib.py, at least in python 2.5. For some interogations, it will cause a msg as: Error code: invalid literal for int() with base 16 to be thrown. Discovered by me in urllib2.urlopen when I tried to grab http://www.bnro.ro/nbrfxrates.xml.

Explanations: In HTTPResponse._read_chunked the chunk length is not checked to be a valid integer, and a ValueError will be raised in such a case.

The fix is:

1. Open the httplib.py file in an editor (e.g. /usr/local/lib/python2.5/httplib.py)
2. Around line 546 localize the code:

    def _read_chunked(self, amt):
        assert self.chunked != _UNKNOWN
        chunk_left = self.chunk_left
        value = ''
 
        # XXX This accumulates chunks by repeated string concatenation,
        # which is not efficient as the number or size of chunks gets big.
        while True:
            if chunk_left is None:
                line = self.fp.readline()
                i = line.find(';')
                if i >= 0:
                    line = line[:i] # strip chunk-extensions
                chunk_left = int(line, 16)

and replace the chunk_left … line with:

                # fix for Error code:  invalid literal for int() with base 16: ''
                try:
                    chunk_left = int(line, 16)          
                except ValueError, msg:          
                    self.close()                    
                    return value