Source code for parsel.csstranslator

from cssselect import GenericTranslator as OriginalGenericTranslator
from cssselect import HTMLTranslator as OriginalHTMLTranslator
from cssselect.xpath import XPathExpr as OriginalXPathExpr
from cssselect.xpath import _unicode_safe_getattr, ExpressionError
from cssselect.parser import FunctionalPseudoElement

[docs]class XPathExpr(OriginalXPathExpr): textnode = False attribute = None
[docs] @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(XPathExpr, 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
[docs] def join(self, combiner, other): super(XPathExpr, self).join(combiner, other) self.textnode = other.textnode self.attribute = other.attribute return self
[docs]class TranslatorMixin(object): """This mixin adds support to CSS pseudo elements via dynamic dispatch. Currently supported pseudo-elements are ``::text`` and ``::attr(ATTR_NAME)``. """
[docs] def xpath_element(self, selector): xpath = super(TranslatorMixin, self).xpath_element(selector) return XPathExpr.from_xpath(xpath)
[docs] def xpath_pseudo_element(self, xpath, pseudo_element): """ Dispatch method that transforms XPath to support pseudo-element """ if isinstance(pseudo_element, FunctionalPseudoElement): method = 'xpath_%s_functional_pseudo_element' % ('-', '_')) method = _unicode_safe_getattr(self, method, None) if not method: raise ExpressionError( "The functional pseudo-element ::%s() is unknown" % 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
[docs] def xpath_attr_functional_pseudo_element(self, xpath, function): """Support selecting attribute values using ::attr() pseudo-element """ if function.argument_types() not in (['STRING'], ['IDENT']): raise ExpressionError( "Expected a single string or ident for ::attr(), got %r" % function.arguments) return XPathExpr.from_xpath(xpath, attribute=function.arguments[0].value)
[docs] def xpath_text_simple_pseudo_element(self, xpath): """Support selecting text nodes using ::text pseudo-element""" return XPathExpr.from_xpath(xpath, textnode=True)
[docs]class GenericTranslator(TranslatorMixin, OriginalGenericTranslator): pass
[docs]class HTMLTranslator(TranslatorMixin, OriginalHTMLTranslator): pass
_translator = HTMLTranslator()
[docs]def css2xpath(query): "Return translated XPath version of a given CSS query" return _translator.css_to_xpath(query)