[XML-SIG] Namespace Stripper Filter

[Clark C. Evans]

Here is my first "real live" python program... anyone who'd 
like to comment for style, please do so as I'm a newbie.
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"""Strips a particular namespace from an XML document."""
from xml.sax import saxutils

class StripperFilter(saxutils.XMLFilterBase ):
    """Does the actual stripping"""
    def __init__(self,nmsp):
        """The namespace to strip is nmsp"""
        saxutils.XMLFilterBase.__init__(self)
        self.nmsp = nmsp
        self.depth = 0
        
    def startElementNS(self, name, qname, attrs):
        """Ignores elements and strips attributes of nmsp"""
        if name[0] != self.nmsp:
            #
            # Warning: For efficiency this dives into the
            #          underlying representation of AttributesNSImpl
            #          and deletes attributes to be stripped.
            #
            #  _attrs should be of the form {(ns_uri, lname): value, ...}.
            #  _qnames of the form {(ns_uri, lname): qname, ...}."""
            #
            for (ns_uri,lname) in attrs._attrs.keys():
                if self.nmsp == ns_uri: del attrs._attrs[(ns_uri,lname)]
            self._cont_handler.startElementNS(name,qname,attrs)
        else:
            self.depth = self.depth + 1

    def characters(self, content):
        if self.depth == 0:
            saxutils.XMLFilterBase.characters(self,content)

    def endElementNS(self, name, qname):
        if self.depth > 0:
            self.depth = self.depth - 1
        else:
            self._cont_handler.endElementNS(name,qname)

    def startPrefixMapping(self, prefix, uri):
        if self.nmsp != uri:
            self._cont_handler.startPrefixMapping(prefix, uri)
                
from xml.sax import make_parser
from xml.sax.handler import feature_namespaces

def testStripper():
    parser = make_parser()
    parser.setFeature(feature_namespaces, 1)
    strip = StripperFilter('namespace-to-strip)
    out = saxutils.XMLGenerator()
    strip.setContentHandler(out)
    parser.setContentHandler(strip)
    parser.parse("test.xml")

if __name__ == '__main__':
    testStripper()