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comparison env/lib/python3.7/site-packages/lxml/cssselect.py @ 0:26e78fe6e8c4 draft

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"planemo upload commit c699937486c35866861690329de38ec1a5d9f783"
author shellac
date Sat, 02 May 2020 07:14:21 -0400
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-1:000000000000 0:26e78fe6e8c4
1 """CSS Selectors based on XPath.
2
3 This module supports selecting XML/HTML tags based on CSS selectors.
4 See the `CSSSelector` class for details.
5
6 This is a thin wrapper around cssselect 0.7 or later.
7 """
8
9 from __future__ import absolute_import
10
11 from . import etree
12 try:
13 import cssselect as external_cssselect
14 except ImportError:
15 raise ImportError(
16 'cssselect does not seem to be installed. '
17 'See http://packages.python.org/cssselect/')
18
19
20 SelectorSyntaxError = external_cssselect.SelectorSyntaxError
21 ExpressionError = external_cssselect.ExpressionError
22 SelectorError = external_cssselect.SelectorError
23
24
25 __all__ = ['SelectorSyntaxError', 'ExpressionError', 'SelectorError',
26 'CSSSelector']
27
28
29 class LxmlTranslator(external_cssselect.GenericTranslator):
30 """
31 A custom CSS selector to XPath translator with lxml-specific extensions.
32 """
33 def xpath_contains_function(self, xpath, function):
34 # Defined there, removed in later drafts:
35 # http://www.w3.org/TR/2001/CR-css3-selectors-20011113/#content-selectors
36 if function.argument_types() not in (['STRING'], ['IDENT']):
37 raise ExpressionError(
38 "Expected a single string or ident for :contains(), got %r"
39 % function.arguments)
40 value = function.arguments[0].value
41 return xpath.add_condition(
42 'contains(__lxml_internal_css:lower-case(string(.)), %s)'
43 % self.xpath_literal(value.lower()))
44
45
46 class LxmlHTMLTranslator(LxmlTranslator, external_cssselect.HTMLTranslator):
47 """
48 lxml extensions + HTML support.
49 """
50
51
52 def _make_lower_case(context, s):
53 return s.lower()
54
55 ns = etree.FunctionNamespace('http://codespeak.net/lxml/css/')
56 ns.prefix = '__lxml_internal_css'
57 ns['lower-case'] = _make_lower_case
58
59
60 class CSSSelector(etree.XPath):
61 """A CSS selector.
62
63 Usage::
64
65 >>> from lxml import etree, cssselect
66 >>> select = cssselect.CSSSelector("a tag > child")
67
68 >>> root = etree.XML("<a><b><c/><tag><child>TEXT</child></tag></b></a>")
69 >>> [ el.tag for el in select(root) ]
70 ['child']
71
72 To use CSS namespaces, you need to pass a prefix-to-namespace
73 mapping as ``namespaces`` keyword argument::
74
75 >>> rdfns = 'http://www.w3.org/1999/02/22-rdf-syntax-ns#'
76 >>> select_ns = cssselect.CSSSelector('root > rdf|Description',
77 ... namespaces={'rdf': rdfns})
78
79 >>> rdf = etree.XML((
80 ... '<root xmlns:rdf="%s">'
81 ... '<rdf:Description>blah</rdf:Description>'
82 ... '</root>') % rdfns)
83 >>> [(el.tag, el.text) for el in select_ns(rdf)]
84 [('{http://www.w3.org/1999/02/22-rdf-syntax-ns#}Description', 'blah')]
85
86 """
87 def __init__(self, css, namespaces=None, translator='xml'):
88 if translator == 'xml':
89 translator = LxmlTranslator()
90 elif translator == 'html':
91 translator = LxmlHTMLTranslator()
92 elif translator == 'xhtml':
93 translator = LxmlHTMLTranslator(xhtml=True)
94 path = translator.css_to_xpath(css)
95 etree.XPath.__init__(self, path, namespaces=namespaces)
96 self.css = css
97
98 def __repr__(self):
99 return '<%s %s for %r>' % (
100 self.__class__.__name__,
101 hex(abs(id(self)))[2:],
102 self.css)