我正在使用Python的lxml库,尝试读取XML文档并进行修改后再写回,但原始的DOCTYPE和XML声明会消失。 我想知道是否有一种简单的方法可以通过lxml或其他解决方案将其放回去?
我正在使用Python的lxml库,尝试读取XML文档并进行修改后再写回,但原始的DOCTYPE和XML声明会消失。 我想知道是否有一种简单的方法可以通过lxml或其他解决方案将其放回去?
总结:
# adds declaration with version and encoding regardless of
# which attributes were present in the original declaration
# expects utf-8 encoding (encode/decode calls)
# depending on your needs you might want to improve that
from lxml import etree
from xml.dom.minidom import parseString
xml1 = '''\
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE root SYSTEM "example.dtd">
<root>...</root>
'''
xml2 = '''\
<root>...</root>
'''
def has_xml_declaration(xml):
return parseString(xml).version
def process(xml):
t = etree.fromstring(xml.encode()).getroottree()
if has_xml_declaration(xml):
print(etree.tostring(t, xml_declaration=True, encoding=t.docinfo.encoding).decode())
else:
print(etree.tostring(t).decode())
process(xml1)
process(xml2)
from lxml import etree
from StringIO import StringIO
tree = etree.parse(StringIO('''<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE root SYSTEM "test" [ <!ENTITY tasty "eggs"> ]>
<root>
<a>&tasty;</a>
</root>
'''))
docinfo = tree.docinfo
print etree.tostring(tree, xml_declaration=True, encoding=docinfo.encoding)
from lxml import etree
from StringIO import StringIO
xml_str = '''<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE root SYSTEM "test" [ <!ENTITY tasty "eggs"> ]>
<root>
<a>&tasty;</a>
</root>
'''
# get the ElementTree using parse
parse_tree = etree.parse(StringIO(xml_str))
encoding = parse_tree.docinfo.encoding
result = etree.tostring(parse_tree, xml_declaration=True, encoding=encoding)
print "%s\nparse ElementTree:\n%s\n" % ('-'*20, result)
# get the ElementTree using fromstring
fromstring_tree = etree.fromstring(xml_str).getroottree()
encoding = fromstring_tree.docinfo.encoding
result = etree.tostring(fromstring_tree, xml_declaration=True, encoding=encoding)
print "%s\nfromstring ElementTree:\n%s\n" % ('-'*20, result)
# DOCTYPE is lost, and no access to encoding
fromstring_element = etree.fromstring(xml_str)
result = etree.tostring(fromstring_element, xml_declaration=True)
print "%s\nfromstring Element:\n%s\n" % ('-'*20, result)
输出结果为:
--------------------
parse ElementTree:
<?xml version='1.0' encoding='iso-8859-1'?>
<!DOCTYPE root SYSTEM "test" [
<!ENTITY tasty "eggs">
]>
<root>
<a>eggs</a>
</root>
--------------------
fromstring ElementTree:
<?xml version='1.0' encoding='iso-8859-1'?>
<!DOCTYPE root SYSTEM "test" [
<!ENTITY tasty "eggs">
]>
<root>
<a>eggs</a>
</root>
--------------------
fromstring Element:
<?xml version='1.0' encoding='ASCII'?>
<root>
<a>eggs</a>
</root>
fromstring()
来保留DOCTYPE和XML声明:import sys
from StringIO import StringIO
from lxml import etree
xml = r'''<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<title>example</title>
</head>
<body>
<p>This is an example</p>
</body>
</html>'''
tree = etree.fromstring(xml).getroottree() # or etree.parse(file)
tree.write(sys.stdout, xml_declaration=True, encoding=tree.docinfo.encoding)
<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>example</title>
</head>
<body>
<p>This is an example</p>
</body>
</html>
'
代替"
,并在<head>
中添加了Content-Type
(可能不正确)。对于@John Keyes 的示例输入,它产生了与答案中etree.tostring()
相同的结果。
tostring
方法的文档吗?我认为它会自动保留 DOCTYPE。 - John Keyes