如何使用ElementTree输出CDATA

我不知道先前版本的拟议代码是否运行良好以及ElementTree模块是否已更新但我遇到了使用此技巧的问题:

import xml.etree.ElementTree as ElementTree

def CDATA(text=None):
    element = ElementTree.Element('![CDATA[')
    element.text = text
    return element

ElementTree._original_serialize_xml = ElementTree._serialize_xml
def _serialize_xml(write, elem, qnames, namespaces,short_empty_elements, **kwargs):
    if elem.tag == '![CDATA[':
        write("\n<{}{}]]>\n".format(elem.tag, elem.text))
        if elem.tail:
            write(_escape_cdata(elem.tail))
    else:
        return ElementTree._original_serialize_xml(write, elem, qnames, namespaces,short_empty_elements, **kwargs)

ElementTree._serialize_xml = ElementTree._serialize['xml'] = _serialize_xml

if __name__ == "__main__":
    import sys

text = """


This is just some sample text.

"""

e = ElementTree.Element("data")
cdata = CDATA(text)
root.append(cdata)

这种方法的问题在于,在传递此异常之后,序列化程序再次将其视为普通标记.我得到的东西是这样的:

etree._original_serialize_xml = etree._serialize_xml
def _serialize_xml(write, elem, qnames, namespaces):
    if elem.tag == '![CDATA[':
        write("\n<%s%s]]>\n" % (
                elem.tag, elem.text))
        return
    return etree._original_serialize_xml(
        write, elem, qnames, namespaces)
etree._serialize_xml = etree._serialize['xml'] = _serialize_xml

当然,我们知道这只会导致很多错误.为什么会这样呢？

答案就在这个小家伙身上:

this was the code I wanted to put inside of CDATA

如果我们已经困住了我们的CDATA并成功通过了它,我们不想再通过原始的序列化函数来检查代码.因此,在"if"块中,只有当CDATA不存在时,我们才必须返回原始序列化函数.在返回原始函数之前,我们错过了"else".

而且在我的版本ElementTree模块中,serialize函数拼命地要求"short_empty_element"参数.所以我推荐的最新版本看起来像这样(也有"尾巴"):

return etree._original_serialize_xml(write, elem, qnames, namespaces)

我得到的输出是:

from xml.etree import ElementTree
from xml import etree

#in order to test it you have to create testing.xml file in the folder with the script
xmlParsedWithET = ElementTree.parse("testing.xml")
root = xmlParsedWithET.getroot()

def CDATA(text=None):
    element = ElementTree.Element('![CDATA[')
    element.text = text
    return element

ElementTree._original_serialize_xml = ElementTree._serialize_xml

def _serialize_xml(write, elem, qnames, namespaces,short_empty_elements, **kwargs):

    if elem.tag == '![CDATA[':
        write("\n<{}{}]]>\n".format(elem.tag, elem.text))
        if elem.tail:
            write(_escape_cdata(elem.tail))
    else:
        return ElementTree._original_serialize_xml(write, elem, qnames, namespaces,short_empty_elements, **kwargs)

ElementTree._serialize_xml = ElementTree._serialize['xml'] = _serialize_xml


text = """


This is just some sample text.

"""
e = ElementTree.Element("data")
cdata = CDATA(text)
root.append(cdata)

#tests
print(root)
print(root.getchildren()[0])
print(root.getchildren()[0].text + "\n\nyay!")

祝你有同样的结果!

这是不可能的AFAIK ...这是一个遗憾.基本上,ElementTree模块假定读者是100%XML兼容的,因此如果他们输出一个CDATA或其他生成等效文本的格式,则无关紧要.

有关详细信息,请参阅Python邮件列表中的此主题.基本上,他们建议使用某种基于DOM的XML库.

实际上这段代码有一个错误,因为你没有]]>在你作为CDATA插入的数据中出现

按是否有一种方式来逃避XML中的CDATA结束令牌？

在这种情况下你应该把它分成两个CDATA,在]]>两者之间分开.

基本上data = data.replace("]]>", "]]]]>")
(不一定正确,请验证)