Source code for parsel.xpathfuncs

import re
from lxml import etree

from six import string_types

from w3lib.html import HTML5_WHITESPACE

regex = '[{}]+'.format(HTML5_WHITESPACE)
replace_html5_whitespaces = re.compile(regex).sub

[docs]def set_xpathfunc(fname, func): """Register a custom extension function to use in XPath expressions. The function ``func`` registered under ``fname`` identifier will be called for every matching node, being passed a ``context`` parameter as well as any parameters passed from the corresponding XPath expression. If ``func`` is ``None``, the extension function will be removed. See more `in lxml documentation`_. .. _`in lxml documentation`: """ ns_fns = etree.FunctionNamespace(None) if func is not None: ns_fns[fname] = func else: del ns_fns[fname]
def setup(): set_xpathfunc('has-class', has_class) def has_class(context, *classes): """has-class function. Return True if all ``classes`` are present in element's class attr. """ if not context.eval_context.get('args_checked'): if not classes: raise ValueError( 'XPath error: has-class must have at least 1 argument') for c in classes: if not isinstance(c, string_types): raise ValueError( 'XPath error: has-class arguments must be strings') context.eval_context['args_checked'] = True node_cls = context.context_node.get('class') if node_cls is None: return False node_cls = ' ' + node_cls + ' ' node_cls = replace_html5_whitespaces(' ', node_cls) for cls in classes: if ' ' + cls + ' ' not in node_cls: return False return True