devtools/htmlparser.py
author Julien Cristau <julien.cristau@logilab.fr>
Wed, 23 Oct 2013 14:18:58 +0200
branchstable
changeset 9305 f7a738afc295
parent 8979 8f5416b1562a
child 10006 8391bf718485
permissions -rw-r--r--
[notification] avoid leaking cnxsets (closes #3243810) When sending notifications, we get each recipient as either an email address or a CWUser. In the latter case, we create a temporary session for that user and use it to send the mail. However, if we later decided to not send the mail after all, we'd leak the session and its cnxset. Add a try block inside the loop to make sure the temporary sessions are closed properly.

# copyright 2003-2013 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# This file is part of CubicWeb.
#
# CubicWeb 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 2.1 of the License, or (at your option)
# any later version.
#
# CubicWeb 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 Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.
"""defines a validating HTML parser used in web application tests"""

import re
import sys
from xml import sax
from cStringIO import StringIO

from lxml import etree

from logilab.common.deprecation import class_deprecated, class_renamed

from cubicweb.view import STRICT_DOCTYPE, TRANSITIONAL_DOCTYPE

STRICT_DOCTYPE = str(STRICT_DOCTYPE)
TRANSITIONAL_DOCTYPE = str(TRANSITIONAL_DOCTYPE)

ERR_COUNT = 0

_REM_SCRIPT_RGX = re.compile(r"<script[^>]*>.*?</script>", re.U|re.M|re.I|re.S)
def _remove_script_tags(data):
    """Remove the script (usually javascript) tags to help the lxml
    XMLParser / HTMLParser do their job. Without that, they choke on
    tags embedded in JS strings.
    """
    # Notice we may want to use lxml cleaner, but it's far too intrusive:
    #
    # cleaner = Cleaner(scripts=True,
    #                   javascript=False,
    #                   comments=False,
    #                   style=False,
    #                   links=False,
    #                   meta=False,
    #                   page_structure=False,
    #                   processing_instructions=False,
    #                   embedded=False,
    #                   frames=False,
    #                   forms=False,
    #                   annoying_tags=False,
    #                   remove_tags=(),
    #                   remove_unknown_tags=False,
    #                   safe_attrs_only=False,
    #                   add_nofollow=False)
    # >>> cleaner.clean_html('<body></body>')
    # '<span></span>'
    # >>> cleaner.clean_html('<!DOCTYPE html><body></body>')
    # '<html><body></body></html>'
    # >>> cleaner.clean_html('<body><div/></body>')
    # '<div></div>'
    # >>> cleaner.clean_html('<html><body><div/><br></body><html>')
    # '<html><body><div></div><br></body></html>'
    # >>> cleaner.clean_html('<html><body><div/><br><span></body><html>')
    # '<html><body><div></div><br><span></span></body></html>'
    #
    # using that, we'll miss most actual validation error we want to
    # catch. For now, use dumb regexp
    return _REM_SCRIPT_RGX.sub('', data)


class Validator(object):
    """ base validator API """
    parser = None

    def parse_string(self, source):
        etree = self._parse(self.preprocess_data(source))
        return PageInfo(source, etree)

    def preprocess_data(self, data):
        return data

    def _parse(self, pdata):
        try:
            return etree.fromstring(pdata, self.parser)
        except etree.XMLSyntaxError as exc:
            def save_in(fname=''):
                file(fname, 'w').write(data)
            new_exc = AssertionError(u'invalid document: %s' % exc)
            new_exc.position = exc.position
            raise new_exc


class DTDValidator(Validator):
    def __init__(self):
        Validator.__init__(self)
        # XXX understand what's happening under windows
        self.parser = etree.XMLParser(dtd_validation=sys.platform != 'win32')

    def preprocess_data(self, data):
        """used to fix potential blockquote mess generated by docutils"""
        if STRICT_DOCTYPE not in data:
            return data
        # parse using transitional DTD
        data = data.replace(STRICT_DOCTYPE, TRANSITIONAL_DOCTYPE)
        tree = self._parse(data)
        namespace = tree.nsmap.get(None)
        # this is the list of authorized child tags for <blockquote> nodes
        expected = 'p h1 h2 h3 h4 h5 h6 div ul ol dl pre hr blockquote address ' \
                   'fieldset table form noscript ins del script'.split()
        if namespace:
            blockquotes = tree.findall('.//{%s}blockquote' % namespace)
            expected = ['{%s}%s' % (namespace, tag) for tag in expected]
        else:
            blockquotes = tree.findall('.//blockquote')
        # quick and dirty approach: remove all blockquotes
        for blockquote in blockquotes:
            parent = blockquote.getparent()
            parent.remove(blockquote)
        data = etree.tostring(tree)
        return '<?xml version="1.0" encoding="UTF-8"?>%s\n%s' % (
            STRICT_DOCTYPE, data)


class XMLValidator(Validator):
    """XML validator, checks that XML is well-formed and used XMLNS are defined"""

    def __init__(self):
        Validator.__init__(self)
        self.parser = etree.XMLParser()

SaxOnlyValidator = class_renamed('SaxOnlyValidator',
                                 XMLValidator,
                                 '[3.17] you should use the '
                                 'XMLValidator class instead')


class XMLSyntaxValidator(Validator):
    """XML syntax validator, check XML is well-formed"""

    class MySaxErrorHandler(sax.ErrorHandler):
        """override default handler to avoid choking because of unknown entity"""
        def fatalError(self, exception):
            # XXX check entity in htmlentitydefs
            if not str(exception).endswith('undefined entity'):
                raise exception
    _parser = sax.make_parser()
    _parser.setContentHandler(sax.handler.ContentHandler())
    _parser.setErrorHandler(MySaxErrorHandler())

    def __init__(self):
        super(XMLSyntaxValidator, self).__init__()
        # XMLParser() wants xml namespaces defined
        # XMLParser(recover=True) will accept almost anything
        #
        # -> use the later but preprocess will check xml well-formness using a
        #    dumb SAX parser
        self.parser = etree.XMLParser(recover=True)

    def preprocess_data(self, data):
        return _remove_script_tags(data)

    def _parse(self, data):
        inpsrc = sax.InputSource()
        inpsrc.setByteStream(StringIO(data))
        try:
            self._parser.parse(inpsrc)
        except sax.SAXParseException, exc:
            new_exc = AssertionError(u'invalid document: %s' % exc)
            new_exc.position = (exc._linenum, exc._colnum)
            raise new_exc
        return super(XMLSyntaxValidator, self)._parse(data)


class XMLDemotingValidator(XMLValidator):
    """ some views produce html instead of xhtml, using demote_to_html

    this is typically related to the use of external dependencies
    which do not produce valid xhtml (google maps, ...)
    """
    __metaclass__ = class_deprecated
    __deprecation_warning__ = '[3.10] this is now handled in testlib.py'

    def preprocess_data(self, data):
        if data.startswith('<?xml'):
            self.parser = etree.XMLParser()
        else:
            self.parser = etree.HTMLParser()
        return data


class HTMLValidator(Validator):

    def __init__(self):
        Validator.__init__(self)
        self.parser = etree.HTMLParser(recover=False)

    def preprocess_data(self, data):
        return _remove_script_tags(data)


class PageInfo(object):
    """holds various informations on the view's output"""
    def __init__(self, source, root):
        self.source = source
        self.etree = root
        self.raw_text = u''.join(root.xpath('//text()'))
        self.namespace = self.etree.nsmap
        self.default_ns = self.namespace.get(None)
        self.a_tags = self.find_tag('a')
        self.h1_tags = self.find_tag('h1')
        self.h2_tags = self.find_tag('h2')
        self.h3_tags = self.find_tag('h3')
        self.h4_tags = self.find_tag('h4')
        self.input_tags = self.find_tag('input')
        self.title_tags = [self.h1_tags, self.h2_tags, self.h3_tags, self.h4_tags]

    def _iterstr(self, tag):
        if self.default_ns is None:
            return ".//%s" % tag
        else:
            return ".//{%s}%s" % (self.default_ns, tag)

    def matching_nodes(self, tag, **attrs):
        for elt in self.etree.iterfind(self._iterstr(tag)):
            eltattrs  = elt.attrib
            for attr, value in attrs.iteritems():
                try:
                    if eltattrs[attr] != value:
                        break
                except KeyError:
                    break
            else: # all attributes match
                yield elt

    def has_tag(self, tag, nboccurs=1, **attrs):
        """returns True if tag with given attributes appears in the page
        `nbtimes` (any if None)
        """
        for elt in self.matching_nodes(tag, **attrs):
            if nboccurs is None: # no need to check number of occurences
                return True
            if not nboccurs: # too much occurences
                return False
            nboccurs -= 1
        if nboccurs == 0: # correct number of occurences
            return True
        return False # no matching tag/attrs

    def find_tag(self, tag, gettext=True):
        """return a list which contains text of all "tag" elements """
        iterstr = self._iterstr(tag)
        if not gettext or tag in ('a', 'input'):
            return [(elt.text, elt.attrib)
                    for elt in self.etree.iterfind(iterstr)]
        return [u''.join(elt.xpath('.//text()'))
                for elt in self.etree.iterfind(iterstr)]

    def appears(self, text):
        """returns True if <text> appears in the page"""
        return text in self.raw_text

    def __contains__(self, text):
        return text in self.source

    def has_title(self, text, level=None):
        """returns True if <h?>text</h?>

        :param level: the title's level (1 for h1, 2 for h2, etc.)
        """
        if level is None:
            for hlist in self.title_tags:
                if text in hlist:
                    return True
            return False
        else:
            hlist = self.title_tags[level - 1]
            return text in hlist

    def has_title_regexp(self, pattern, level=None):
        """returns True if <h?>pattern</h?>"""
        sre = re.compile(pattern)
        if level is None:
            for hlist in self.title_tags:
                for title in hlist:
                    if sre.match(title):
                        return True
            return False
        else:
            hlist = self.title_tags[level - 1]
            for title in hlist:
                if sre.match(title):
                    return True
            return False

    def has_link(self, text, url=None):
        """returns True if <a href=url>text</a> was found in the page"""
        for link_text, attrs in self.a_tags:
            if text == link_text:
                if url is None:
                    return True
                try:
                    href = attrs['href']
                    if href == url:
                        return True
                except KeyError:
                    continue
        return False

    def has_link_regexp(self, pattern, url=None):
        """returns True if <a href=url>pattern</a> was found in the page"""
        sre = re.compile(pattern)
        for link_text, attrs in self.a_tags:
            if sre.match(link_text):
                if url is None:
                    return True
                try:
                    href = attrs['href']
                    if href == url:
                        return True
                except KeyError:
                    continue
        return False

VALMAP = {None: None,
          'dtd': DTDValidator,
          'xml': XMLValidator,
          'html': HTMLValidator,
          }