Limnoria/plugins/Google/parser.py

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###
# Copyright (c) 2020-2021, Valentin Lorentz
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# * Redistributions of source code must retain the above copyright notice,
# this list of conditions, and the following disclaimer.
# * Redistributions in binary form must reproduce the above copyright notice,
# this list of conditions, and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
# * Neither the name of the author of this software nor the name of
# contributors to this software may be used to endorse or promote products
# derived from this software without specific prior written consent.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
###
import enum
import collections
from html.parser import HTMLParser
import supybot.utils as utils
result = collections.namedtuple('result', 'link title snippet')
@enum.unique
class ParserState(enum.Enum):
OUTSIDE = 0
IN_LINK = 1
IN_TITLE = 2
TITLE_PARSED = 3
BREADCRUMBS_PARSED = 5
LINK_PARSED = 6
@enum.unique
class DomMark(enum.Enum):
"""A mark on an element in the stack, to know when to change state when
poping the element from the stack."""
HEADING = 1
BREADCRUMBS = 2
STACKED_TAGS = ('div', 'span', 'a')
class GoogleHTMLParser(HTMLParser):
def __init__(self):
super().__init__()
self.stack = []
self.results = []
self.reset_current_result()
def reset_current_result(self):
self.state = ParserState.OUTSIDE
self.current_link = None
self.current_title = None
self.current_snippet = None
def handle_starttag(self, tag, attrs):
attrs = dict(attrs)
classes = attrs.get('class', '').split()
if tag in STACKED_TAGS:
self.stack.append(tag)
if tag == 'a' and attrs['href'].startswith('/url?q=') \
and self.state == ParserState.OUTSIDE:
self.state = ParserState.IN_LINK
href = attrs['href'][len('/url?q='):]
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self.current_link = utils.web.urlunquote(href.split('&sa')[0])
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elif tag == 'h3' and 'a' in self.stack and self.state == ParserState.IN_LINK:
self.state = ParserState.IN_TITLE
mark = DomMark.HEADING
def handle_endtag(self, tag):
if tag in STACKED_TAGS:
item = self.stack.pop()
assert item == tag, (item, tag)
if tag == 'a' and self.state in (
ParserState.IN_LINK, ParserState.IN_TITLE, ParserState.BREADCRUMBS_PARSED):
if self.current_title is None:
# That wasn't a result
self.state = ParserState.OUTSIDE
else:
self.state = ParserState.LINK_PARSED
def handle_data(self, data):
if self.state == ParserState.IN_TITLE:
self.current_title = data
self.state = ParserState.TITLE_PARSED
elif self.state == ParserState.TITLE_PARSED:
self.state = ParserState.BREADCRUMBS_PARSED
elif self.state == ParserState.LINK_PARSED:
self.current_snippet = data
self.state = ParserState.OUTSIDE
self.build_result()
def build_result(self):
self.results.append(result(
link=self.current_link,
title=self.current_title,
snippet=self.current_snippet,
))
self.reset_current_result()
if __name__ == '__main__':
parser = GoogleHTMLParser()
with open('google.html') as fd:
parser.feed(fd.read())
print(parser.results)