Remove "ds:" in signed XML tree namespace in python's signxml

Solution 1:

I came up with a function that changes namespace ns_from to ns_to. Removing a namespace can just be realized by setting ns_to to "".

(However, this solution seems to be problematic according the comments by the OP)

def replace_namespace(root, ns_from, ns_to):
    """
    Merge the namespace ns_from to ns_to in the tree rooted at the root, everything that belongs to ns_from will be in
    ns_to
    To do so, I
    1. change the tag of root
        Change the namespace of root from ns_from to ns_to
    2. change the attribute
        Change the namespace of root from ns_from to ns_to
    3. change the nsmap
        delete the ns_from space
    4. keep other property
    """
    # change the tag of root
    tag = etree.QName(root.tag)
    # if there are attributes belong to namespace ns_from, update to namespace of the
    # attributes to namespace ns_to
    if tag.namespace == ns_from:
        root.tag = '{%s}%s' % (ns_to, tag.localname)

    # change the attribute of root
    # if there are attributes belong to namespace ns_from, update to namespace of the
    # attributes to namespace ns_to
    root_attrib_dict = dict(root.attrib)
    new_attrib_dict = {}
    for key, value in root_attrib_dict.items():
        key_QName = etree.QName(key)
        if key_QName.namespace == ns_from:
            new_key = '{%s}%s' % (ns_to, key_QName.localname)
            new_attrib_dict[new_key] = value
        else:
            new_attrib_dict[key] = value

    # set the new nsmap
    new_nsmap = root.nsmap.copy()
    for ns_key, ns_value in root.nsmap.items():
        if ns_value == ns_from:
            del new_nsmap[ns_key]

    # make the updated root
    new_root = etree.Element(root.tag, attrib=new_attrib_dict, nsmap=new_nsmap)

    # copy other properties
    new_root.text = root.text
    new_root.tail = root.tail

    # call recursively
    for old_root in root[:]:
        new_root.append(replace_namespace(old_root, ns_from, ns_to))

    return new_root

Test Codes:

input_xml_string = """
<facturaElectronicaCompraVenta )

Which gives:

<?xml version='1.0' encoding='UTF-8'?>
<facturaElectronicaCompraVenta >this answser from the following two aspects:


I use a recursive function. The original answer only reset nsmap for the root node. So there will be a  % (target_nt, tag.localname)

    # change the attribute of root
    # if there are attributes belong to other namespace, update to namespace of the
    # attributes to target_nt
    root_attrib_dict = dict(root.attrib)
    new_attrib_dict = {}
    for key, value in root_attrib_dict.items():
        key_QName = etree.QName(key)
        if key_QName.namespace is not None:
            new_key = '{%s}%s' % (target_nt, key_QName.localname)
        else:
            new_key = key
        new_attrib_dict[new_key] = value

    # set the new nsmap
    # only keep the target_nt, set to default namespace
    new_nsmap = {None: target_nt}

    # make the updated root
    new_root = etree.Element(root.tag, attrib=new_attrib_dict, nsmap=new_nsmap)

    # copy other properties
    new_root.text = root.text
    new_root.tail = root.tail

    # call recursively
    for old_root in root[:]:
        new_root.append(set_namsespace(old_root, target_nt))

    return new_root

root = etree.fromstring(input_xml_string)
target_ns = "http://www.w3.org/2001/XMLSchema-instance"
new_root = set_namsespace(root, target_ns)

# create a new elementtree with new_root so that we can use the
# .write method.
tree = etree.ElementTree()
tree._setroot(new_root)

tree.write('done.xml',
           pretty_print=True, xml_declaration=True, encoding='UTF-8')

<?xml version='1.0' encoding='UTF-8'?>
<facturaElectronicaCompraVenta _nt:
            del new_nsmap[ns_key]
            new_nsmap[None] = target_nt

    # make the updated root
    root_attrib_dict = dict(root.attrib)
    new_root = etree.Element(root.tag, attrib=root_attrib_dict, nsmap=new_nsmap)

    # copy other properties
    new_root.text = root.text
    new_root.tail = root.tail

    # call recursively
    for old_root in root[:]:
        new_root.append(set_namsespace(old_root, target_nt))

    return new_root

root = etree.fromstring(input_xml_string)
target_ns = "http://www.w3.org/2000/09/xmldsig#"
new_root = set_namsespace(root, target_ns)

<?xml version='1.0' encoding='UTF-8'?>
<facturaElectronicaCompraVenta ,nsmap={ None: 'http://www.w3.org/2000/09/xmldsig#' })
        signed_root = XMLSigner(c14n_algorithm='http://www.w3.org/2001/10/xml-exc-c14n#').sign(
            root,
            key=open('example.key').read(),
            cert=open('example.pem').read()
        )
        return signed_root

if __name__ == '__main__':
    root = get_xml_tree_root()
    signed_root = get_signed_xml(root)
    signed_xml_file = open('signed.xml','wb')
    signed_xml_file.write(etree.tostring(signed_root,encoding='UTF-8'))
    signed_xml_file.close()
    print(etree.tostring(signed_root,encoding='UTF-8',pretty_print=True).decode('UTF-8'))

<facturaElectronicaCompraVenta>

  <header/>

  <detail/>

  <Signature  rel="nofollow noreferrer">https://github.com/XML-Security/signxml/issues/171