如何让 lxml.Element.xpath 不展开实体？
[英]How can I get lxml.Element.xpath to not expand entities?
问题描述
If I use lxml.etree.XMLParser(resolve_entities=False) to parse XML content, it correctly returns text nodes without the entities expanded.
如果我使用lxml.etree.XMLParser(resolve_entities=False)来解析 XML 内容，它会正确返回文本节点而不展开实体。 (I'd prefer that it just leave the text of the entity in there; instead it truncates at the first entity. （我希望它只是将实体的文本留在其中；相反，它会在第一个实体处截断。
from io import BytesIO
from lxml import etree
xml_content = b"""<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE foo [
<!ELEMENT foo ANY>
<!ENTITY bar "benign">
]>
<body>
<expansion> This is a &bar; entity expansion with weird spacing. </expansion>
</body>"""
nonexpanding_parser = etree.XMLParser(resolve_entities=False)
unexpanded_tree = etree.parse(BytesIO(xml_content), nonexpanding_parser)
elements = unexpanded_tree.xpath('//expansion')
elements[0].text # ' This is a '
However, when I try to call the xpath function normalize-space on it, it expands the entity, which I'm trying to avoid:但是，当我尝试在其上调用xpath function normalize-space时，它会扩展实体，这是我试图避免的：
elements[0].xpath('normalize-space(.)') # 'This is a benign entity expansion with weird spacing.'
I suppose I can write my own normalization method, but I'd rather avoid that and I'm not 100% sure what the exact spec of that function is, and I'm working on replacing it in my code, so I want it to behave the same.我想我可以编写自己的规范化方法，但我宁愿避免这种情况，而且我不能 100% 确定 function 的确切规格是什么，我正在努力在我的代码中替换它，所以我想要它表现得一样。
Really the question is : Can I get something like elements[0].xpath('normalize-space(.)') that will return This is a .真正的问题是：我可以得到类似elements[0].xpath('normalize-space(.)')东西，它会返回This is a .
Even better:更好的是：
-
This is a entity expansion with weird spacing.(this is the preferred example)（这是首选示例） -
This is a &bar; entity expansion with weird spacing.
1 个解决方案
解决方案1
0 2022-01-19 01:23:30
It's not exactly elegant, but you could extract all the text nodes, join them in Python, and normalize the space.它不是很优雅，但是您可以提取所有文本节点，将它们加入 Python 并规范化空间。
(Pdb) text_fragments = unexpanded_tree.xpath('//expansion/text()')
(Pdb) text_fragments
[' This is a ', ' entity expansion with weird spacing. ']
(Pdb) ' '.join(''.join(text_fragments).split())
'This is a entity expansion with weird spacing.'
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