在ElementTree 1.2中抑制名称空间前缀

Question

在python 2.7(使用etree 1.3)中,我可以在这样的元素上抑制XML前缀:

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" />'

该register_namespace功能在1.3中添加.我试图以与版本1.2.6的python 2.6的etree兼容的方式删除前缀.这是我尝试过的:

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" />'

这不是我想要的.前缀仍然存在但是空白.有没有办法彻底删除它们？

Answer 1

看后在python2.6的对ElementTree的源代码,则:是硬的编码fixtag功能.作为一种解决方法,这就是我所做的:

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')

如果这篇文章过时,代码将保留在这里.

Answer 2

我在文件的顶部创建了一个方法,只需在标记字符串所在的位置使用它.我把它命名为'ns_tag',但你可以随心所欲地命名它.

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

例:

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
        ...