解析lxml中的html主体片段 [英] parse html body fragment in lxml
问题描述
我正在尝试解析html的片段:
I'm trying to parse a fragment of html:
<body><h1>title</h1><img src=""></body>
我使用lxml.html.fromstring.而且它使我发疯，因为它不断剥离片段的<body>标签:
I use lxml.html.fromstring. And it is driving me insane because it keeps stripping the <body> tag of my fragments:
> lxml.html.fromstring('<html><h1>a</h1></html>').tag
'html'
> lxml.html.fromstring('<div><h1>a</h1></div>').tag
'div'
> lxml.html.fromstring('<body><h1>a</h1></body>').tag
'h1'
我还尝试了document_fromstring，fragment_fromstring，clean_html和page_structure=False等，但没有任何效果.
I've also tried the document_fromstring, fragment_fromstring, clean_html with page_structure=False, etc... nothing works.
我需要使用lxml，因为我将html片段传递给了PyQuery.
I need to use lxml, since I'm passing the html fragment to PyQuery.
我只希望lxml不会弄乱我的html片段.可以这样做吗?
I just want lxml to not mess with my html fragment. Is it possible to do that?
推荐答案
.fragment_fromstring()也会删除<html>标记；基本上，每当您没有拥有HTML文档(带有<html>顶级元素和/或doctype)时，.fromstring()都会退回到.fragment_fromstring()，并且该方法会删除<html>和<body>标签.
.fragment_fromstring() removes the <html> tag as well; basically, whenever you do not have a HTML document (with a <html> top-level element and/or a doctype), .fromstring() falls back to .fragment_fromstring() and that method removes both the <html> and the <body> tags, always.
解决方法是告诉.fragment_fromstring()给您一个<body> parent 标签:
The work-around is to tell .fragment_fromstring() to give you a <body> parent tag:
>>> lxml.html.fragment_fromstring('<body><h1>a</h1></body>', create_parent='body')
<Element body at 0x10d06fbf0>
这不会保留原始<body>标记上的任何属性.
This does not preserve any attributes on the original <body> tag.
另一种解决方法是使用.document_fromstring()方法，该方法会将文档包装在<html>标记中，然后可以再次将其删除:
Another work-around is to use the .document_fromstring() method, which will wrap your document in a <html> tag, which you then can remove again:
>>> lxml.html.document_fromstring('<body><h1>a</h1></body>')[0]
<Element body at 0x10d06fcb0>
此确实保留<body>上的属性:
>>> lxml.html.document_fromstring('<body class="foo"><h1>a</h1></body>')[0].attrib
{'class': 'foo'}
在第一个示例中使用.document_fromstring()函数可以得出:
Using the .document_fromstring() function on your first example gives:
>>> body = lxml.html.document_fromstring('<body><h1>title</h1><img src=""></body>')[0]
>>> lxml.html.tostring(body)
'<body><h1>title</h1><img src=""></body>'
如果只想在没有 HTML标记的情况下执行此操作，请执行lxml.html.fromstring()的操作并测试完整的文档:
If you only want to do this if there is no HTML tag, do what lxml.html.fromstring() does and test for a full document:
htmltest = lxml.html._looks_like_full_html_bytes if isinstance(inputtext, str) else lxml.html._looks_like_full_html_unicode
if htmltest(inputtext):
tree = lxml.html.fromstring(inputtext)
else:
tree = lxml.html.document_fromstring(inputtext)[0]
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