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from cssselect import GenericTranslator, HTMLTranslator
from cssselect.xpath import _unicode_safe_getattr, XPathExpr, ExpressionError
from cssselect.parser import FunctionalPseudoElement
class ScrapyXPathExpr(XPathExpr):
textnode = False
attribute = None
@classmethod
def from_xpath(cls, xpath, textnode=False, attribute=None):
x = cls(path=xpath.path, element=xpath.element, condition=xpath.condition)
x.textnode = textnode
x.attribute = attribute
return x
def __str__(self):
path = super(ScrapyXPathExpr, self).__str__()
if self.textnode:
if path == '*':
path = 'text()'
elif path.endswith('::*/*'):
path = path[:-3] + 'text()'
else:
path += '/text()'
if self.attribute is not None:
if path.endswith('::*/*'):
path = path[:-2]
path += '/@%s' % self.attribute
return path
def join(self, combiner, other):
super(ScrapyXPathExpr, self).join(combiner, other)
self.textnode = other.textnode
self.attribute = other.attribute
return self
class TranslatorMixin(object):
def xpath_element(self, selector):
xpath = super(TranslatorMixin, self).xpath_element(selector)
return ScrapyXPathExpr.from_xpath(xpath)
def xpath_pseudo_element(self, xpath, pseudo_element):
if isinstance(pseudo_element, FunctionalPseudoElement):
method = 'xpath_%s_functional_pseudo_element' % (
pseudo_element.name.replace('-', '_'))
method = _unicode_safe_getattr(self, method, None)
if not method:
raise ExpressionError(
"The functional pseudo-element ::%s() is unknown"
% pseudo_element.name)
xpath = method(xpath, pseudo_element)
else:
method = 'xpath_%s_simple_pseudo_element' % (
pseudo_element.replace('-', '_'))
method = _unicode_safe_getattr(self, method, None)
if not method:
raise ExpressionError(
"The pseudo-element ::%s is unknown"
% pseudo_element)
xpath = method(xpath)
return xpath
def xpath_attr_functional_pseudo_element(self, xpath, function):
if function.argument_types() not in (['STRING'], ['IDENT']):
raise ExpressionError(
"Expected a single string or ident for ::attr(), got %r"
% function.arguments)
return ScrapyXPathExpr.from_xpath(xpath,
attribute=function.arguments[0].value)
def xpath_text_simple_pseudo_element(self, xpath):
"""Support selecting text nodes using ::text pseudo-element"""
return ScrapyXPathExpr.from_xpath(xpath, textnode=True)
class ScrapyGenericTranslator(TranslatorMixin, GenericTranslator):
pass
class ScrapyHTMLTranslator(TranslatorMixin, HTMLTranslator):
pass
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