Suppressing namespace prefixes in ElementTree 1.2

Question

In python 2.7 (with etree 1.3), I can suppress the XML prefixes on elements like this:

Python 2.7.1 (r271:86832, Jun 16 2011, 16:59:05) 
[GCC 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2335.15.00)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import xml.etree.ElementTree as etree
>>> etree.VERSION
'1.3.0'
>>> something = etree.Element('{http://some.namespace}token')
>>> etree.tostring(something)
'<ns0:token xmlns:ns0="http://some.namespace" />'
>>> etree.register_namespace('', 'http://some.namespace')
>>> etree.tostring(something)
'<token xmlns="http://some.namespace" />'

The register_namespace function was added in 1.3. I'm trying to remove the prefix in a way that is compatible with python 2.6's etree at version 1.2.6. Here's what I've tried:

Python 2.6.7 (r267:88850, Jul 31 2011, 19:30:54) 
[GCC 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2335.15.00)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import xml.etree.ElementTree as etree
>>> etree.VERSION
'1.2.6'
>>> something = etree.Element('{http://some.namespace}token')
>>> etree.tostring(something)
'<ns0:token xmlns:ns0="http://some.namespace" />'
>>> etree._namespace_map['http://some.namespace'] = ''
>>> etree.tostring(something)
'<:token xmlns:="http://some.namespace" />'

This is not what I want. The prefixes are still there but are blank. Is there any way to remove them completely?

Contraoctave

See my answer under https://mcmap.net/q/136201/-python-elementtree-module-how-to-ignore-the-namespace-of-xml-files-to-locate-matching-element-when-using-the-method-quot-find-quot-quot-findall-quot for a more general solution – Larock

Answer 1

After looking at the source code for ElementTree in python2.6, the : is hard coded in the fixtag function. As a workaround, here's what I did:

from xml.etree import ElementTree as etree

if etree.VERSION[0:3] == '1.2':
    #in etree < 1.3, this is a workaround for supressing prefixes

    def fixtag(tag, namespaces):
        import string
        # given a decorated tag (of the form {uri}tag), return prefixed
        # tag and namespace declaration, if any
        if isinstance(tag, etree.QName):
            tag = tag.text
        namespace_uri, tag = string.split(tag[1:], "}", 1)
        prefix = namespaces.get(namespace_uri)
        if namespace_uri not in namespaces:
            prefix = etree._namespace_map.get(namespace_uri)
            if namespace_uri not in etree._namespace_map:
                prefix = "ns%d" % len(namespaces)
            namespaces[namespace_uri] = prefix
            if prefix == "xml":
                xmlns = None
            else:
                if prefix is not None:
                    nsprefix = ':' + prefix
                else:
                    nsprefix = ''
                xmlns = ("xmlns%s" % nsprefix, namespace_uri)
        else:
            xmlns = None
        if prefix is not None:
            prefix += ":"
        else:
            prefix = ''

        return "%s%s" % (prefix, tag), xmlns

    etree.fixtag = fixtag
    etree._namespace_map['http://some.namespace'] = None
else:
    #For etree > 1.3, use register_namespace function
    etree.register_namespace('', 'http://some.namespace')

In case this post ever gets out of date, the code is maintained here.

Contraoctave

There might have been some updates since then. Latest is at github.com/pycollada/pycollada/blob/master/collada/xmlutil.py – Contraoctave

Thanks. I'm on OS X and couldn't be bothered upgrading my Python install (2.5) for a quick bit of XML editing, so this was all I needed. – Tansy

Answer 2

I created a method at the top of my file and simply use it where the tag string should be. I named it 'ns_tag', but you could name it whatever you want.

def ns_tag(tag):
    return str( ElementTree.QName('http://some.namespace/api/4/', tag) )

Example:

root = ElementTree.fromstring(xml)
success = root.find(ns_tag('success'))
if success.text == 'true':
    for node in root.find(ns_tag('items')):
        id = node.find(ns_tag('id')).text
        ...

Millda

That helps when working with the file, but if you save the file, the prefixes will still be there. This question is about supression the prefixes when saving the file. – Contraoctave

Answer 3

It's a hack, but this worked well for me on Jython 2.5.2

    ns=re.match('^\{([^\}]+)\}', mydoc.getroot().tag ).group(1)
    etree._namespace_map[ns]='STRIPME'
    etree.tostring( mydoc.getroot() ).replace( 'STRIPME:', '' )

Thorathoracic

Answer 4

For removing namespace from tags, I use this code where a taget object is a subclass of TreeBuilder. In both methods start and end, we remove the unwanted namespace.

from xml.etree.ElementTree import XML, XMLParser, tostring, TreeBuilder

class StripNamespace(TreeBuilder):
    def start(self, tag, attrib):
        index = tag.find('}')
        if index != -1:
            tag = tag[index+1:]
        super(StripNamespace, self).start(tag, attrib)
    def end(self, tag):
        index = tag.find('}')
        if index != -1:
            tag = tag[index+1:]
        super(StripNamespace, self).end(tag)

target = StripNamespace()
parser = XMLParser(target=target)
with open("DmsDesc.xml") as f:
    content = f.read()
root = XML(content, parser=parser)
print tostring(root)

Simple and pretty.

Duplex