我注意到 xml 实体 " 会自动强制转换为它们真正的原始字符:

>>> from lxml import etree as et
>>> parser = et.XMLParser()
>>> xml = et.fromstring("<root><elem>&quot;hello world&quot;</elem></root>", parser)
>>> print et.tostring(xml, pretty_print=1)
<root>
  <elem>"hello world"</elem>
</root>

>>> 

我找到了一个相关的old(2009-02-07) thread :

s = cStringIO.StringIO(""""She's the MAN!"""") e = etree.parse(s,etree.XMLParser(resolve_entities=False))

请注意还有 etree.fromstring()。

etree.tostring(e) '"She\'s the MAN!"'

I would have expected resolve_entities=False to have prevented the translation of, eg, " to ".

“resolve_entities”选项适用于 DTD 中定义的实体 您希望保留其中的引用而不是已解析的值。 您提到的实体是 XML 规范的一部分，而不是 DTD。

is there another way to prevent this behavior (or, if nothing else, reverse it after the fact)?

好吧，您得到的是格式正确的 XML。请问你为什么需要 输出中的实体引用？

不过，答案是你为什么要这样做，这个问题没有直接的答案。我很惊讶，因为 etree 解析器在没有提供禁用它的选项的情况下强制转换。

以下示例显示了为什么我需要此解决方案，此 xml 用于 xbmc skinning解析器:

>>> print open("/tmp/so.xml").read() #the original file
<window id="1234">
        <defaultcontrol>101</defaultcontrol>
        <controls>
                <control type="button" id="101">
                        <onfocus>Dialog.Close(212)</onfocus>
                        <onfocus>SetFocus(11)</onfocus>
                </control>
                <control type="button" id="102">
                        <visible>StringCompare(VideoPlayer.PlotOutline,Stream.IsPlaying) + !Skin.HasSetting(Stream.IsUpdated)</visible>
                        <onfocus>RunScript(script.test)</onfocus>
                        <onfocus>SetFocus(11)</onfocus>
                </control>
                <control type="button" id="103">
                        <visible>SubString(VideoPlayer.PlotOutline,Video.IsPlaying)</visible>
                        <onfocus>Close</onfocus>
                        <onfocus>RunScript(&quot;/.xbmc/addons/script.hello.world/default.py&quot;,&quot;$INFO[VideoPlayer.Album]&quot;,&quot;$INFO[VideoPlayer.Genre]&quot;)</onfocus>
                </control>
        </controls>
</window>

>>> root = et.parse("/tmp/so.xml", parser)
>>> r = root.getroot()
>>> for c in r:
...     for cc in c:
...         if cc.attrib.get('id') == "103":
...             cc.remove(cc[1]) #remove 1 element, it's just a demonstrate
... 
>>> o = open("/tmp/so.xml", "w")
>>> o.write(et.tostring(r, pretty_print=1)) #save it back
>>> o.close()
>>> print open("/tmp/so.xml").read() #the file after implemented 
<window id="1234">
        <defaultcontrol>101</defaultcontrol>
        <controls>
                <control type="button" id="101">
                        <onfocus>Dialog.Close(212)</onfocus>
                        <onfocus>SetFocus(11)</onfocus>
                </control>
                <control type="button" id="102">
                        <visible>StringCompare(VideoPlayer.PlotOutline,Stream.IsPlaying) + !Skin.HasSetting(Stream.IsUpdated)</visible>
                        <onfocus>RunScript(script.test)</onfocus>
                        <onfocus>SetFocus(11)</onfocus>
                </control>
                <control type="button" id="103">
                        <visible>SubString(VideoPlayer.PlotOutline,Video.IsPlaying)</visible>
                        <onfocus>RunScript("/.xbmc/addons/script.hello.world/default.py","$INFO[VideoPlayer.Album]","$INFO[VideoPlayer.Genre]")</onfocus>
                </control>
        </controls>
</window>

>>> 

如您所见，最后 id "103"下的 onfocus 元素，" 不再是原来的形式，如果"$INFO[VideoPlayer.Album]"变量包含嵌套引号并变为无效和错误的 ""test""。

那么，我是否可以通过任何 hacky 方式来保持 " 的原始形式？

[更新]: 对于感兴趣的人，其他 3 个预定义的 xml 实体，即 gt、lt 和 amp 只能通过使用 method= 进行转换“html” 和 script 标签。无论是 lxml VS xml.etree.ElementTree 还是 python2 VS python3 都具有相同的机制并让人混淆:

>>> from lxml import etree as et
>>> r = et.fromstring("<root><script>&quot;&apos;&amp;&gt;&lt;</script><p>&quot;&apos;&amp;&gt;&lt;</p></root>")
>>> print et.tostring(r, pretty_print=1, method="xml")
<root>
  <script>"'&amp;&gt;&lt;</script>
  <p>"'&amp;&gt;&lt;</p>
</root>

>>> print et.tostring(r, pretty_print=1, method="html")
<root><script>"'&><</script><p>"'&amp;&gt;&lt;</p></root>

>>> 

[更新2]: 以下是所有可能的 html 标签的列表:

#https://github.com/html5lib/html5lib-python/blob/master/html5lib/sanitizer.py
acceptable_elements = ['a', 'abbr', 'acronym', 'address', 'area',
'article', 'aside', 'audio', 'b', 'big', 'blockquote', 'br', 'button',
'canvas', 'caption', 'center', 'cite', 'code', 'col', 'colgroup',
'command', 'datagrid', 'datalist', 'dd', 'del', 'details', 'dfn',
'dialog', 'dir', 'div', 'dl', 'dt', 'em', 'event-source', 'fieldset',
'figcaption', 'figure', 'footer', 'font', 'form', 'header', 'h1',
'h2', 'h3', 'h4', 'h5', 'h6', 'hr', 'i', 'img', 'input', 'ins',
'keygen', 'kbd', 'label', 'legend', 'li', 'm', 'map', 'menu', 'meter',
'multicol', 'nav', 'nextid', 'ol', 'output', 'optgroup', 'option',
'p', 'pre', 'progress', 'q', 's', 'samp', 'section', 'select',
'small', 'sound', 'source', 'spacer', 'span', 'strike', 'strong',
'sub', 'sup', 'table', 'tbody', 'td', 'textarea', 'time', 'tfoot',
'th', 'thead', 'tr', 'tt', 'u', 'ul', 'var', 'video']
from lxml import etree as et
for e in acceptable_elements:
    r = et.fromstring(e.join(["<", ">hello&amp;world</", ">"]))
    s = et.tostring(r, pretty_print=1, method="html")
    closed_tag = "</" + e + ">"
    if closed_tag not in s:
        print s

运行此代码，您将看到如下输出:

<area>

<br>

<col>

<hr>

<img>

<input>

如您所见，只打印了打开标签，其余的都进入了黑洞。我测试了所有 5 个 xml 实体并且都具有相同的行为。太困惑了。使用 HTMLParser 时不会发生这种情况，所以我猜想在 fromstring(method should be default to xml) 和 tostring(method="html") 步骤之间存在错误。而且我发现它与实体无关，因为“< img=""> hello ”(没有实体)也被截断为 < img="">(而且你好只是无处可去，如果使用 method =，它可以随时出现xml”打印出来)。

最佳答案

from xml.sax.saxutils import escape
from lxml import etree

def to_string(xdoc):
    r = ""
    for action, elem in etree.iterwalk(xdoc, events=("start", "end")):
        if action == 'start':
            text = escape(elem.text, {"'": "'", "\"": """}) if elem.text is not None else ""
            attrs = "".join([' %s="%s"' % (k, v) for k, v in elem.attrib.items()])
            r += "<%s%s>%s" % (elem.tag, attrs, text)
        elif action == 'end':
            r += "</%s>%s" % (elem.tag, elem.tail if elem.tail else "\n")
    return r
xdoc = etree.fromstring(xml_text)
s = to_string(xdoc)

关于python - lxml - 是否有任何 hacky 方法来保留“？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/27687677/