weboob-devel/weboob/tools/parsers/lxmlparser.py

129 lines
4.2 KiB
Python

# -*- coding: utf-8 -*-
# Copyright(C) 2010-2011 Christophe Benz
#
# This file is part of weboob.
#
# weboob is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# weboob is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with weboob. If not, see <http://www.gnu.org/licenses/>.
import re
import lxml.html as html
import lxml.etree as etree
from .iparser import IParser
from ..browser import BrokenPageError
__all__ = ['LxmlHtmlParser', 'LxmlXmlParser']
class LxmlParser(IParser):
"""
Parser using lxml.
Note that it is not available on every systems.
"""
def get_parser(encoding=None):
pass
def parse(self, data, encoding=None):
if encoding is None:
parser = None
else:
parser = self.get_parser(encoding=encoding)
return self.module.parse(data, parser)
def tostring(self, element):
return self.module.tostring(element, encoding=unicode)
def tocleanstring(self, element):
txt = [txt.strip() for txt in element.itertext()]
txt = u' '.join(txt) # 'foo bar'
txt = re.sub('\s+', ' ', txt) # 'foo bar'
return txt.strip()
def strip(self, s):
doc = self.module.fromstring(s) # parse html/xml string
return self.tocleanstring(doc)
@classmethod
def select(cls, element, selector, nb=None, method='cssselect', **kwargs):
"""
Select one or many elements from an element, using lxml cssselect by default.
Raises :class:`weboob.tools.browser.browser.BrokenPageError` if not found.
:param element: element on which to apply selector
:type element: object
:param selector: CSS or XPath expression
:type selector: str
:param method: (cssselect|xpath)
:type method: str
:param nb: number of elements expected to be found. Use None for
undefined number, and 'many' for 1 to infinite
:type nb: :class:`int` or :class:`str`
:rtype: Element
"""
if method == 'cssselect':
results = element.cssselect(selector, **kwargs)
elif method == 'xpath':
results = element.xpath(selector, **kwargs)
else:
raise NotImplementedError('Only the cssselect and xpath methods are supported')
if nb is None:
return results
elif isinstance(nb, basestring) and nb == 'many':
if results is None or len(results) == 0:
raise BrokenPageError('Element not found with selector "%s"' % selector)
elif len(results) == 1:
raise BrokenPageError('Only one element found with selector "%s"' % selector)
else:
return results
elif isinstance(nb, int) and nb > 0:
if results is None:
raise BrokenPageError('Element not found with selector "%s"' % selector)
elif len(results) < nb:
raise BrokenPageError('Not enough elements found (%d expected) with selector "%s"' % (nb, selector))
else:
return results[0] if nb == 1 else results
else:
raise Exception('Unhandled value for kwarg "nb": %s' % nb)
class LxmlHtmlParser(LxmlParser):
"""
Parser using lxml.
Note that it is not available on every systems.
"""
def __init__(self, *args, **kwargs):
self.module = html
def get_parser(self, encoding=None):
return html.HTMLParser(encoding=encoding)
class LxmlXmlParser(LxmlParser):
"""
Parser using lxml.
Note that it is not available on every systems.
"""
def __init__(self, *args, **kwargs):
self.module = etree
def get_parser(self, encoding=None):
return etree.XMLParser(encoding=encoding, strip_cdata=False)