Source code for woob.browser.filters.base

# Copyright(C) 2017  woob project
# This file is part of woob.
# woob is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# woob is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# GNU Lesser General Public License for more details.
# You should have received a copy of the GNU Lesser General Public License
# along with woob. If not, see <>.

from functools import wraps

import lxml.html

from woob.exceptions import ParseError
from import getLogger, DEBUG_FILTERS
from import NO_DEFAULT as _NO_DEFAULT, NoDefaultType

__all__ = ['FilterError', 'ItemNotFound', 'Filter',]

# Defined for compatibility.
NoDefault = NoDefaultType

[docs]class FilterError(ParseError): pass
[docs]class ItemNotFound(FilterError): pass
class _Filter: _creation_counter = 0 def __init__(self, default=_NO_DEFAULT): self._key = None self._obj = None self.default = default self._creation_counter = _Filter._creation_counter _Filter._creation_counter += 1 def __or__(self, o): self.default = o return self def __and__(self, o): if isinstance(o, type) and issubclass(o, _Filter): o = o() o.selector = self return o def __str__(self): return self.__class__.__name__ def __call__(self, item): raise NotImplementedError() def default_or_raise(self, exception): if self.default is not _NO_DEFAULT: return self.default else: raise exception def highlight_el(self, el, item=None): obj = self._obj or item try: if not hasattr(obj, 'saved_attrib'): return if not return except AttributeError: return if el not in obj.saved_attrib: obj.saved_attrib[el] = dict(el.attrib) el.attrib['style'] = 'color: white !important; background: red !important;' if self._key: el.attrib['title'] = 'woob field: %s' % self._key def debug(*args): """ A decorator function to provide some debug information in Filters. It prints by default the name of the Filter and the input value. """ def decorator(function): logger = getLogger('woob.browser.b2filters') def print_debug(self, value): result = '' outputvalue = value if isinstance(value, list): from lxml import etree outputvalue = '' first = True for element in value: if first: first = False else: outputvalue += ', ' if isinstance(element, etree.ElementBase): outputvalue += "%s" % etree.tostring(element, encoding="unicode") else: outputvalue += "%r" % element if self._obj is not None: result += "%s" % self._obj._random_id if self._key is not None: result += ".%s" % self._key name = str(self) result += " %s(%r" % (name, outputvalue) for arg in self.__dict__: if arg.startswith('_') or arg == "selector": continue if arg == 'default' and getattr(self, arg) == _NO_DEFAULT: continue result += ", %s=%r" % (arg, getattr(self, arg)) result += ')' logger.log(DEBUG_FILTERS, result) @wraps(function) def wrapper(self, value): if logger.isEnabledFor(DEBUG_FILTERS): print_debug(self, value) res = function(self, value) return res return wrapper return decorator
[docs]class Filter(_Filter): """ Class used to filter on a HTML element given as call parameter to return matching elements. Filters can be chained, so the parameter supplied to constructor can be either a xpath selector string, or an other filter called before. >>> from lxml.html import etree >>> f = CleanDecimal(CleanText('//p'), replace_dots=True) >>> f(etree.fromstring('<html><body><p>blah: <span>229,90</span></p></body></html>')) Decimal('229.90') """ def __init__(self, selector=None, default=_NO_DEFAULT): """ :param default: default value in case the filter fails to find or parse the requested value """ super(Filter, self).__init__(default=default) self.selector = selector
[docs] def select(self, selector, item): if isinstance(selector, str): ret = item.xpath(selector) elif isinstance(selector, _Filter): selector._key = self._key selector._obj = self._obj ret = selector(item) elif callable(selector): ret = selector(item) else: ret = selector if isinstance(ret, lxml.html.HtmlElement): self.highlight_el(ret, item) elif isinstance(ret, list): for el in ret: if isinstance(el, lxml.html.HtmlElement): self.highlight_el(el, item) return ret
def __call__(self, item): return self.filter(, item))
[docs] @debug() def filter(self, value): """ This method has to be overridden by children classes. """ raise NotImplementedError()
class _Selector(Filter): def filter(self, elements): if elements is not None: return elements else: return self.default_or_raise(FilterError('Element %r not found' % self.selector))