searxng/searx/engines/google_scholar.py

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# SPDX-License-Identifier: AGPL-3.0-or-later
# lint: pylint
"""Google (Scholar)
For detailed description of the *REST-full* API see: `Query Parameter
Definitions`_.
.. _Query Parameter Definitions:
https://developers.google.com/custom-search/docs/xml_results#WebSearch_Query_Parameter_Definitions
"""
# pylint: disable=invalid-name
from urllib.parse import urlencode
from datetime import datetime
from typing import Optional
from lxml import html
from searx.utils import (
eval_xpath,
eval_xpath_getindex,
eval_xpath_list,
extract_text,
)
from searx.engines.google import (
get_lang_info,
time_range_dict,
detect_google_sorry,
)
# pylint: disable=unused-import
from searx.engines.google import (
supported_languages_url,
_fetch_supported_languages,
)
# pylint: enable=unused-import
# about
about = {
"website": 'https://scholar.google.com',
"wikidata_id": 'Q494817',
"official_api_documentation": 'https://developers.google.com/custom-search',
"use_official_api": False,
"require_api_key": False,
"results": 'HTML',
}
# engine dependent config
categories = ['science', 'scientific publications']
paging = True
language_support = True
use_locale_domain = True
time_range_support = True
safesearch = False
send_accept_language_header = True
def time_range_url(params):
"""Returns a URL query component for a google-Scholar time range based on
``params['time_range']``. Google-Scholar does only support ranges in years.
To have any effect, all the Searx ranges (*day*, *week*, *month*, *year*)
are mapped to *year*. If no range is set, an empty string is returned.
Example::
&as_ylo=2019
"""
# as_ylo=2016&as_yhi=2019
ret_val = ''
if params['time_range'] in time_range_dict:
ret_val = urlencode({'as_ylo': datetime.now().year - 1})
return '&' + ret_val
def request(query, params):
"""Google-Scholar search request"""
offset = (params['pageno'] - 1) * 10
lang_info = get_lang_info(params, supported_languages, language_aliases, False)
# subdomain is: scholar.google.xy
lang_info['subdomain'] = lang_info['subdomain'].replace("www.", "scholar.")
query_url = (
'https://'
+ lang_info['subdomain']
+ '/scholar'
+ "?"
+ urlencode({'q': query, **lang_info['params'], 'ie': "utf8", 'oe': "utf8", 'start': offset})
)
query_url += time_range_url(params)
params['url'] = query_url
params['cookies']['CONSENT'] = "YES+"
params['headers'].update(lang_info['headers'])
params['headers']['Accept'] = 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8'
# params['google_subdomain'] = subdomain
return params
def parse_gs_a(text: Optional[str]):
"""Parse the text written in green.
Possible formats:
* "{authors} - {journal}, {year} - {publisher}"
* "{authors} - {year} - {publisher}"
* "{authors} - {publisher}"
"""
if text is None or text == "":
return None, None, None, None
s_text = text.split(' - ')
authors = s_text[0].split(', ')
publisher = s_text[-1]
if len(s_text) != 3:
return authors, None, publisher, None
# the format is "{authors} - {journal}, {year} - {publisher}" or "{authors} - {year} - {publisher}"
# get journal and year
journal_year = s_text[1].split(', ')
# journal is optional and may contains some coma
if len(journal_year) > 1:
journal = ', '.join(journal_year[0:-1])
if journal == '':
journal = None
else:
journal = None
# year
year = journal_year[-1]
try:
publishedDate = datetime.strptime(year.strip(), '%Y')
except ValueError:
publishedDate = None
return authors, journal, publisher, publishedDate
def response(resp): # pylint: disable=too-many-locals
"""Get response from google's search request"""
results = []
detect_google_sorry(resp)
# which subdomain ?
# subdomain = resp.search_params.get('google_subdomain')
# convert the text to dom
dom = html.fromstring(resp.text)
# parse results
for result in eval_xpath_list(dom, '//div[@data-cid]'):
title = extract_text(eval_xpath(result, './/h3[1]//a'))
if not title:
# this is a [ZITATION] block
continue
pub_type = extract_text(eval_xpath(result, './/span[@class="gs_ct1"]'))
if pub_type:
pub_type = pub_type[1:-1].lower()
url = eval_xpath_getindex(result, './/h3[1]//a/@href', 0)
content = extract_text(eval_xpath(result, './/div[@class="gs_rs"]'))
authors, journal, publisher, publishedDate = parse_gs_a(
extract_text(eval_xpath(result, './/div[@class="gs_a"]'))
)
if publisher in url:
publisher = None
# cited by
comments = extract_text(eval_xpath(result, './/div[@class="gs_fl"]/a[starts-with(@href,"/scholar?cites=")]'))
# link to the html or pdf document
html_url = None
pdf_url = None
doc_url = eval_xpath_getindex(result, './/div[@class="gs_or_ggsm"]/a/@href', 0, default=None)
doc_type = extract_text(eval_xpath(result, './/span[@class="gs_ctg2"]'))
if doc_type == "[PDF]":
pdf_url = doc_url
else:
html_url = doc_url
results.append(
{
'template': 'paper.html',
'type': pub_type,
'url': url,
'title': title,
'authors': authors,
'publisher': publisher,
'journal': journal,
'publishedDate': publishedDate,
'content': content,
'comments': comments,
'html_url': html_url,
'pdf_url': pdf_url,
}
)
# parse suggestion
for suggestion in eval_xpath(dom, '//div[contains(@class, "gs_qsuggest_wrap")]//li//a'):
# append suggestion
results.append({'suggestion': extract_text(suggestion)})
for correction in eval_xpath(dom, '//div[@class="gs_r gs_pda"]/a'):
results.append({'correction': extract_text(correction)})
return results