mirror of https://github.com/searxng/searxng.git
458 lines
14 KiB
Python
458 lines
14 KiB
Python
# SPDX-License-Identifier: AGPL-3.0-or-later
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# lint: pylint
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"""
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DuckDuckGo Lite
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~~~~~~~~~~~~~~~
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"""
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from typing import TYPE_CHECKING
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import re
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from urllib.parse import urlencode
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import json
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import babel
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import lxml.html
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from searx import (
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locales,
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redislib,
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external_bang,
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)
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from searx.utils import (
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eval_xpath,
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eval_xpath_getindex,
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extract_text,
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)
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from searx.network import get # see https://github.com/searxng/searxng/issues/762
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from searx import redisdb
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from searx.enginelib.traits import EngineTraits
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if TYPE_CHECKING:
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import logging
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logger: logging.Logger
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traits: EngineTraits
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about = {
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"website": 'https://lite.duckduckgo.com/lite/',
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"wikidata_id": 'Q12805',
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"use_official_api": False,
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"require_api_key": False,
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"results": 'HTML',
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}
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send_accept_language_header = True
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"""DuckDuckGo-Lite tries to guess user's prefered language from the HTTP
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``Accept-Language``. Optional the user can select a region filter (but not a
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language).
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"""
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# engine dependent config
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categories = ['general', 'web']
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paging = True
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time_range_support = True
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safesearch = True # user can't select but the results are filtered
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url = 'https://lite.duckduckgo.com/lite/'
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# url_ping = 'https://duckduckgo.com/t/sl_l'
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time_range_dict = {'day': 'd', 'week': 'w', 'month': 'm', 'year': 'y'}
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form_data = {'v': 'l', 'api': 'd.js', 'o': 'json'}
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def cache_vqd(query, value):
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"""Caches a ``vqd`` value from a query."""
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c = redisdb.client()
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if c:
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logger.debug("cache vqd value: %s", value)
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key = 'SearXNG_ddg_web_vqd' + redislib.secret_hash(query)
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c.set(key, value, ex=600)
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def get_vqd(query):
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"""Returns the ``vqd`` that fits to the *query*. If there is no ``vqd`` cached
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(:py:obj:`cache_vqd`) the query is sent to DDG to get a vqd value from the
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response.
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.. hint::
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If an empty string is returned there are no results for the ``query`` and
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therefore no ``vqd`` value.
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DDG's bot detection is sensitive to the ``vqd`` value. For some search terms
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(such as extremely long search terms that are often sent by bots), no ``vqd``
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value can be determined.
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If SearXNG cannot determine a ``vqd`` value, then no request should go out
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to DDG:
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A request with a wrong ``vqd`` value leads to DDG temporarily putting
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SearXNG's IP on a block list.
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Requests from IPs in this block list run into timeouts.
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Not sure, but it seems the block list is a sliding window: to get my IP rid
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from the bot list I had to cool down my IP for 1h (send no requests from
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that IP to DDG).
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TL;DR; the ``vqd`` value is needed to pass DDG's bot protection and is used
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by all request to DDG:
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- DuckDuckGo Lite: ``https://lite.duckduckgo.com/lite`` (POST form data)
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- DuckDuckGo Web: ``https://links.duckduckgo.com/d.js?q=...&vqd=...``
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- DuckDuckGo Images: ``https://duckduckgo.com/i.js??q=...&vqd=...``
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- DuckDuckGo Videos: ``https://duckduckgo.com/v.js??q=...&vqd=...``
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- DuckDuckGo News: ``https://duckduckgo.com/news.js??q=...&vqd=...``
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"""
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value = None
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c = redisdb.client()
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if c:
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key = 'SearXNG_ddg_web_vqd' + redislib.secret_hash(query)
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value = c.get(key)
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if value or value == b'':
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value = value.decode('utf-8')
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logger.debug("re-use cached vqd value: %s", value)
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return value
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query_url = 'https://duckduckgo.com/?' + urlencode({'q': query})
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res = get(query_url)
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doc = lxml.html.fromstring(res.text)
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for script in doc.xpath("//script[@type='text/javascript']"):
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script = script.text
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if 'vqd="' in script:
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value = script[script.index('vqd="') + 5 :]
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value = value[: value.index('"')]
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break
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logger.debug("new vqd value: '%s'", value)
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cache_vqd(query, value)
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return value
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def get_ddg_lang(eng_traits: EngineTraits, sxng_locale, default='en_US'):
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"""Get DuckDuckGo's language identifier from SearXNG's locale.
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DuckDuckGo defines its languages by region codes (see
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:py:obj:`fetch_traits`).
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To get region and language of a DDG service use:
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.. code: python
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eng_region = traits.get_region(params['searxng_locale'], traits.all_locale)
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eng_lang = get_ddg_lang(traits, params['searxng_locale'])
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It might confuse, but the ``l`` value of the cookie is what SearXNG calls
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the *region*:
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.. code:: python
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# !ddi paris :es-AR --> {'ad': 'es_AR', 'ah': 'ar-es', 'l': 'ar-es'}
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params['cookies']['ad'] = eng_lang
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params['cookies']['ah'] = eng_region
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params['cookies']['l'] = eng_region
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.. hint::
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`DDG-lite <https://lite.duckduckgo.com/lite>`__ does not offer a language
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selection to the user, only a region can be selected by the user
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(``eng_region`` from the example above). DDG-lite stores the selected
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region in a cookie::
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params['cookies']['kl'] = eng_region # 'ar-es'
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"""
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return eng_traits.custom['lang_region'].get( # type: ignore
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sxng_locale, eng_traits.get_language(sxng_locale, default)
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)
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ddg_reg_map = {
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'tw-tzh': 'zh_TW',
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'hk-tzh': 'zh_HK',
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'ct-ca': 'skip', # ct-ca and es-ca both map to ca_ES
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'es-ca': 'ca_ES',
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'id-en': 'id_ID',
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'no-no': 'nb_NO',
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'jp-jp': 'ja_JP',
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'kr-kr': 'ko_KR',
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'xa-ar': 'ar_SA',
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'sl-sl': 'sl_SI',
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'th-en': 'th_TH',
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'vn-en': 'vi_VN',
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}
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ddg_lang_map = {
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# use ar --> ar_EG (Egypt's arabic)
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"ar_DZ": 'lang_region',
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"ar_JO": 'lang_region',
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"ar_SA": 'lang_region',
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# use bn --> bn_BD
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'bn_IN': 'lang_region',
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# use de --> de_DE
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'de_CH': 'lang_region',
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# use en --> en_US,
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'en_AU': 'lang_region',
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'en_CA': 'lang_region',
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'en_GB': 'lang_region',
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# Esperanto
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'eo_XX': 'eo',
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# use es --> es_ES,
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'es_AR': 'lang_region',
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'es_CL': 'lang_region',
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'es_CO': 'lang_region',
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'es_CR': 'lang_region',
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'es_EC': 'lang_region',
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'es_MX': 'lang_region',
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'es_PE': 'lang_region',
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'es_UY': 'lang_region',
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'es_VE': 'lang_region',
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# use fr --> rf_FR
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'fr_CA': 'lang_region',
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'fr_CH': 'lang_region',
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'fr_BE': 'lang_region',
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# use nl --> nl_NL
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'nl_BE': 'lang_region',
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# use pt --> pt_PT
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'pt_BR': 'lang_region',
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# skip these languages
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'od_IN': 'skip',
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'io_XX': 'skip',
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'tokipona_XX': 'skip',
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}
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def request(query, params):
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# request needs a vqd argument
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vqd = get_vqd(query)
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# quote ddg bangs
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query_parts = []
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# for val in re.split(r'(\s+)', query):
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for val in re.split(r'(\s+)', query):
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if not val.strip():
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continue
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if val.startswith('!') and external_bang.get_node(external_bang.EXTERNAL_BANGS, val[1:]):
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val = f"'{val}'"
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query_parts.append(val)
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query = ' '.join(query_parts)
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eng_region = traits.get_region(params['searxng_locale'], traits.all_locale)
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# eng_lang = get_ddg_lang(traits, params['searxng_locale'])
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params['url'] = url
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params['method'] = 'POST'
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params['data']['q'] = query
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# The API is not documented, so we do some reverse engineering and emulate
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# what https://lite.duckduckgo.com/lite/ does when you press "next Page"
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# link again and again ..
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params['headers']['Content-Type'] = 'application/x-www-form-urlencoded'
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params['data']['vqd'] = vqd
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# initial page does not have an offset
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if params['pageno'] == 2:
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# second page does have an offset of 20
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offset = (params['pageno'] - 1) * 20
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params['data']['s'] = offset
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params['data']['dc'] = offset + 1
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elif params['pageno'] > 2:
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# third and following pages do have an offset of 20 + n*50
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offset = 20 + (params['pageno'] - 2) * 50
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params['data']['s'] = offset
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params['data']['dc'] = offset + 1
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# initial page does not have additional data in the input form
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if params['pageno'] > 1:
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params['data']['o'] = form_data.get('o', 'json')
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params['data']['api'] = form_data.get('api', 'd.js')
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params['data']['nextParams'] = form_data.get('nextParams', '')
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params['data']['v'] = form_data.get('v', 'l')
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params['headers']['Referer'] = 'https://lite.duckduckgo.com/'
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params['data']['kl'] = eng_region
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params['cookies']['kl'] = eng_region
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params['data']['df'] = ''
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if params['time_range'] in time_range_dict:
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params['data']['df'] = time_range_dict[params['time_range']]
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params['cookies']['df'] = time_range_dict[params['time_range']]
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logger.debug("param data: %s", params['data'])
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logger.debug("param cookies: %s", params['cookies'])
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return params
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def response(resp):
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if resp.status_code == 303:
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return []
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results = []
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doc = lxml.html.fromstring(resp.text)
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result_table = eval_xpath(doc, '//html/body/form/div[@class="filters"]/table')
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if len(result_table) == 2:
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# some locales (at least China) does not have a "next page" button and
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# the layout of the HTML tables is different.
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result_table = result_table[1]
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elif not len(result_table) >= 3:
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# no more results
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return []
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else:
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result_table = result_table[2]
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# update form data from response
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form = eval_xpath(doc, '//html/body/form/div[@class="filters"]/table//input/..')
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if len(form):
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form = form[0]
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form_data['v'] = eval_xpath(form, '//input[@name="v"]/@value')[0]
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form_data['api'] = eval_xpath(form, '//input[@name="api"]/@value')[0]
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form_data['o'] = eval_xpath(form, '//input[@name="o"]/@value')[0]
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logger.debug('form_data: %s', form_data)
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tr_rows = eval_xpath(result_table, './/tr')
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# In the last <tr> is the form of the 'previous/next page' links
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tr_rows = tr_rows[:-1]
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len_tr_rows = len(tr_rows)
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offset = 0
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while len_tr_rows >= offset + 4:
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# assemble table rows we need to scrap
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tr_title = tr_rows[offset]
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tr_content = tr_rows[offset + 1]
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offset += 4
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# ignore sponsored Adds <tr class="result-sponsored">
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if tr_content.get('class') == 'result-sponsored':
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continue
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a_tag = eval_xpath_getindex(tr_title, './/td//a[@class="result-link"]', 0, None)
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if a_tag is None:
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continue
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td_content = eval_xpath_getindex(tr_content, './/td[@class="result-snippet"]', 0, None)
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if td_content is None:
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continue
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results.append(
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{
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'title': a_tag.text_content(),
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'content': extract_text(td_content),
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'url': a_tag.get('href'),
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}
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)
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return results
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def fetch_traits(engine_traits: EngineTraits):
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"""Fetch languages & regions from DuckDuckGo.
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SearXNG's ``all`` locale maps DuckDuckGo's "Alle regions" (``wt-wt``).
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DuckDuckGo's language "Browsers prefered language" (``wt_WT``) makes no
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sense in a SearXNG request since SearXNG's ``all`` will not add a
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``Accept-Language`` HTTP header. The value in ``engine_traits.all_locale``
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is ``wt-wt`` (the region).
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Beside regions DuckDuckGo also defines its languages by region codes. By
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example these are the english languages in DuckDuckGo:
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- en_US
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- en_AU
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- en_CA
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- en_GB
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The function :py:obj:`get_ddg_lang` evaluates DuckDuckGo's language from
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SearXNG's locale.
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"""
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# pylint: disable=too-many-branches, too-many-statements
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# fetch regions
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engine_traits.all_locale = 'wt-wt'
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# updated from u661.js to u.7669f071a13a7daa57cb / should be updated automatically?
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resp = get('https://duckduckgo.com/dist/util/u.7669f071a13a7daa57cb.js')
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if not resp.ok: # type: ignore
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print("ERROR: response from DuckDuckGo is not OK.")
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pos = resp.text.find('regions:{') + 8 # type: ignore
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js_code = resp.text[pos:] # type: ignore
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pos = js_code.find('}') + 1
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regions = json.loads(js_code[:pos])
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for eng_tag, name in regions.items():
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if eng_tag == 'wt-wt':
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engine_traits.all_locale = 'wt-wt'
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continue
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region = ddg_reg_map.get(eng_tag)
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if region == 'skip':
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continue
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if not region:
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eng_territory, eng_lang = eng_tag.split('-')
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region = eng_lang + '_' + eng_territory.upper()
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try:
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sxng_tag = locales.region_tag(babel.Locale.parse(region))
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except babel.UnknownLocaleError:
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print("ERROR: %s (%s) -> %s is unknown by babel" % (name, eng_tag, region))
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continue
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conflict = engine_traits.regions.get(sxng_tag)
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if conflict:
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if conflict != eng_tag:
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print("CONFLICT: babel %s --> %s, %s" % (sxng_tag, conflict, eng_tag))
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continue
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engine_traits.regions[sxng_tag] = eng_tag
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# fetch languages
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engine_traits.custom['lang_region'] = {}
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pos = resp.text.find('languages:{') + 10 # type: ignore
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js_code = resp.text[pos:] # type: ignore
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pos = js_code.find('}') + 1
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js_code = '{"' + js_code[1:pos].replace(':', '":').replace(',', ',"')
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languages = json.loads(js_code)
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for eng_lang, name in languages.items():
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if eng_lang == 'wt_WT':
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continue
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babel_tag = ddg_lang_map.get(eng_lang, eng_lang)
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if babel_tag == 'skip':
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continue
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try:
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if babel_tag == 'lang_region':
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sxng_tag = locales.region_tag(babel.Locale.parse(eng_lang))
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engine_traits.custom['lang_region'][sxng_tag] = eng_lang
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continue
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sxng_tag = locales.language_tag(babel.Locale.parse(babel_tag))
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except babel.UnknownLocaleError:
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print("ERROR: language %s (%s) is unknown by babel" % (name, eng_lang))
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continue
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conflict = engine_traits.languages.get(sxng_tag)
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if conflict:
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if conflict != eng_lang:
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print("CONFLICT: babel %s --> %s, %s" % (sxng_tag, conflict, eng_lang))
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continue
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engine_traits.languages[sxng_tag] = eng_lang
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