diff options
Diffstat (limited to 'searx/engines/google_scholar.py')
| -rw-r--r-- | searx/engines/google_scholar.py | 121 |
1 files changed, 63 insertions, 58 deletions
diff --git a/searx/engines/google_scholar.py b/searx/engines/google_scholar.py index 38aaf904b..6f33d1e1a 100644 --- a/searx/engines/google_scholar.py +++ b/searx/engines/google_scholar.py @@ -1,19 +1,18 @@ # SPDX-License-Identifier: AGPL-3.0-or-later # lint: pylint -"""Google (Scholar) +"""This is the implementation of the Google Scholar engine. -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 +Compared to other Google services the Scholar engine has a simple GET REST-API +and there does not exists `async` API. Even though the API slightly vintage we +can make use of the :ref:`google API` to assemble the arguments of the GET +request. """ -# pylint: disable=invalid-name +from typing import TYPE_CHECKING +from typing import Optional from urllib.parse import urlencode from datetime import datetime -from typing import Optional from lxml import html from searx.utils import ( @@ -23,20 +22,21 @@ from searx.utils import ( extract_text, ) +from searx.exceptions import SearxEngineCaptchaException + +from searx.engines.google import fetch_traits # pylint: disable=unused-import from searx.engines.google import ( - get_lang_info, + get_google_info, time_range_dict, - detect_google_sorry, ) +from searx.enginelib.traits import EngineTraits -# pylint: disable=unused-import -from searx.engines.google import ( - fetch_traits, - supported_languages_url, - _fetch_supported_languages, -) +if TYPE_CHECKING: + import logging -# pylint: enable=unused-import + logger: logging.Logger + +traits: EngineTraits # about about = { @@ -52,53 +52,62 @@ about = { 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:: +def time_range_args(params): + """Returns a dictionary with a time range arguments based on + ``params['time_range']``. - &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 + Google Scholar supports a detailed search by year. Searching by *last + month* or *last week* (as offered by SearXNG) is uncommon for scientific + publications and is not supported by Google Scholar. + To limit the result list when the users selects a range, all the SearXNG + ranges (*day*, *week*, *month*, *year*) are mapped to *year*. If no range + is set an empty dictionary of arguments is returned. Example; when + user selects a time range (current year minus one in 2022): -def request(query, params): - """Google-Scholar search request""" + .. code:: python - offset = (params['pageno'] - 1) * 10 - lang_info = get_lang_info(params, supported_languages, language_aliases, False) + { 'as_ylo' : 2021 } - # subdomain is: scholar.google.xy - lang_info['subdomain'] = lang_info['subdomain'].replace("www.", "scholar.") + """ + ret_val = {} + if params['time_range'] in time_range_dict: + ret_val['as_ylo'] = datetime.now().year - 1 + return ret_val - 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 +def detect_google_captcha(dom): + """In case of CAPTCHA Google Scholar open its own *not a Robot* dialog and is + not redirected to ``sorry.google.com``. + """ + if eval_xpath(dom, "//form[@id='gs_captcha_f']"): + raise SearxEngineCaptchaException() + - 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' +def request(query, params): + """Google-Scholar search request""" - # params['google_subdomain'] = subdomain + google_info = get_google_info(params, traits) + # subdomain is: scholar.google.xy + google_info['subdomain'] = google_info['subdomain'].replace("www.", "scholar.") + + args = { + 'q': query, + **google_info['params'], + 'start': (params['pageno'] - 1) * 10, + 'as_sdt': '2007', # include patents / to disable set '0,5' + 'as_vis': '0', # include citations / to disable set '1' + } + args.update(time_range_args(params)) + + params['url'] = 'https://' + google_info['subdomain'] + '/scholar?' + urlencode(args) + params['cookies'] = google_info['cookies'] + params['headers'].update(google_info['headers']) return params @@ -139,19 +148,15 @@ def parse_gs_a(text: Optional[str]): def response(resp): # pylint: disable=too-many-locals - """Get response from google's search request""" + """Parse response from Google Scholar""" results = [] - detect_google_sorry(resp) - - # which subdomain ? - # subdomain = resp.search_params.get('google_subdomain') - # convert the text to dom dom = html.fromstring(resp.text) + detect_google_captcha(dom) # parse results - for result in eval_xpath_list(dom, '//div[@data-cid]'): + for result in eval_xpath_list(dom, '//div[@data-rp]'): title = extract_text(eval_xpath(result, './/h3[1]//a')) @@ -159,7 +164,7 @@ def response(resp): # pylint: disable=too-many-locals # this is a [ZITATION] block continue - pub_type = extract_text(eval_xpath(result, './/span[@class="gs_ct1"]')) + pub_type = extract_text(eval_xpath(result, './/span[@class="gs_ctg2"]')) if pub_type: pub_type = pub_type[1:-1].lower() |