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[refactor] engine: duckduckgo - https://html.duckduckgo.com/html
The entire source code of the duckduckgo engine has been reengineered and purified. 1. DDG used the URL https://html.duckduckgo.com/html for no-JS requests whose response is also easier to parse than the previous https://lite.duckduckgo.com/lite/ URL 2. the bot detection of DDG has so far caused problems and often led to a CAPTCHA, this can be circumvented using `'Sec-Fetch-Mode'] = “navigate”` Closes: https://github.com/searxng/searxng/issues/3927 Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>
This commit is contained in:
Markus Heiser
Markus Heiser
parent
f63f97c56c
commit
b183e620d8
1 changed files with 116 additions and 106 deletions
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@ -18,7 +18,6 @@ from searx import (
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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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@ -54,31 +53,33 @@ 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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url = "https://html.duckduckgo.com/html"
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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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__CACHE = []
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def cache_vqd(query, value):
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def _cache_key(data: dict):
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return 'SearXNG_ddg_web_vqd' + redislib.secret_hash(f"{data['q']}//{data['kl']}")
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def cache_vqd(data: dict, 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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c.set(_cache_key(data), value, ex=600)
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else:
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logger.debug("MEM cache vqd value: %s", value)
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if len(__CACHE) > 100: # cache vqd from last 100 queries
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__CACHE.pop(0)
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__CACHE.append((_cache_key(data), value))
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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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def get_vqd(data):
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"""Returns the ``vqd`` that fits to the *query* (``data`` from HTTP POST).
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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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@ -106,28 +107,23 @@ def get_vqd(query):
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- DuckDuckGo News: ``https://duckduckgo.com/news.js??q=...&vqd=...``
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"""
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key = _cache_key(data)
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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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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 = extr(script, 'vqd="', '"')
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break
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logger.debug("new vqd value: '%s'", value)
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if value is not None:
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cache_vqd(query, value)
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else:
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for k, value in __CACHE:
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if k == key:
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logger.debug("MEM re-use CACHED vqd value: %s", value)
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return value
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return None
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def get_ddg_lang(eng_traits: EngineTraits, sxng_locale, default='en_US'):
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@ -155,9 +151,10 @@ def get_ddg_lang(eng_traits: EngineTraits, sxng_locale, default='en_US'):
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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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`DDG-lite <https://lite.duckduckgo.com/lite>`__ and the *no Javascript*
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page https://html.duckduckgo.com/html do not offer a language selection
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to the user, only a region can be selected by the user (``eng_region``
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from the example above). DDG-lite and *no Javascript* store 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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@ -241,10 +238,25 @@ def request(query, params):
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query = quote_ddg_bangs(query)
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# request needs a vqd argument
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vqd = get_vqd(query)
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if len(query) >= 500:
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# DDG does not accept queries with more than 499 chars
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params["url"] = None
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return
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# Advanced search syntax ends in CAPTCHA
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# https://duckduckgo.com/duckduckgo-help-pages/results/syntax/
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query = [
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x.removeprefix("site:").removeprefix("intitle:").removeprefix("inurl:").removeprefix("filetype:")
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for x in query.split()
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]
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eng_region = traits.get_region(params['searxng_locale'], traits.all_locale)
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if eng_region == "wt-wt":
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# https://html.duckduckgo.com/html sets an empty value for "all".
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eng_region = ""
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params['data']['kl'] = eng_region
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params['cookies']['kl'] = eng_region
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# eng_lang = get_ddg_lang(traits, params['searxng_locale'])
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params['url'] = url
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@ -252,54 +264,82 @@ def request(query, params):
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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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# what https://html.duckduckgo.com/html does when you press "next Page" link
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# 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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params['headers']['Sec-Fetch-Dest'] = "document"
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params['headers']['Sec-Fetch-Mode'] = "navigate" # at least this one is used by ddg's bot detection
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params['headers']['Sec-Fetch-Site'] = "same-origin"
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params['headers']['Sec-Fetch-User'] = "?1"
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# Form of the initial search page does have empty values in the form
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if params['pageno'] == 1:
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params['data']['b'] = ""
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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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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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# initial page does not have these additional data in the input form
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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['headers']['Referer'] = url
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params['data']['kl'] = eng_region
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params['cookies']['kl'] = eng_region
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# from here on no more params['data'] shuld be set, since this dict is
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# needed to get a vqd value from the cache ..
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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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vqd = get_vqd(params['data'])
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# Certain conditions must be met in order to call up one of the
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# following pages ...
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if vqd:
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params['data']['vqd'] = vqd # follow up pages / requests needs a vqd argument
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else:
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# Don't try to call follow up pages without a vqd value. DDG
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# recognizes this as a request from a bot. This lowers the
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# reputation of the SearXNG IP and DDG starts to activate CAPTCHAs.
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params["url"] = None
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return
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if params['searxng_locale'].startswith("zh"):
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# Some locales (at least China) do not have a "next page" button and ddg
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# will return a HTTP/2 403 Forbidden for a request of such a page.
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params["url"] = None
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return
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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 detect_ddg_captcha(dom):
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"""In case of CAPTCHA ddg open its own *not a Robot* dialog and is
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not redirected to CAPTCHA page.
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"""
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if eval_xpath(dom, "//form[@id='challenge-form']"):
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# set suspend time to zero is OK --> ddg does not block the IP
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raise SearxEngineCaptchaException(suspended_time=0)
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def is_ddg_captcha(dom):
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"""In case of CAPTCHA ddg response its own *not a Robot* dialog and is not
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redirected to a CAPTCHA page."""
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return bool(eval_xpath(dom, "//form[@id='challenge-form']"))
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def response(resp):
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@ -309,37 +349,34 @@ def response(resp):
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results = []
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doc = lxml.html.fromstring(resp.text)
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detect_ddg_captcha(doc)
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result_table = eval_xpath(doc, '//html/body/form/div[@class="filters"]/table')
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if is_ddg_captcha(doc):
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# set suspend time to zero is OK --> ddg does not block the IP
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raise SearxEngineCaptchaException(suspended_time=0, message=f"CAPTCHA ({resp.search_params['data'].get('kl')})")
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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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form = eval_xpath(doc, '//input[@name="vqd"]/..')
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if len(form):
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# some locales (at least China) does not have a "next page" button
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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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form_vqd = eval_xpath(form, '//input[@name="vqd"]/@value')[0]
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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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cache_vqd(resp.search_params["data"], form_vqd)
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len_tr_rows = len(tr_rows)
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offset = 0
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# just select "web-result" and ignore results of class "result--ad result--ad--small"
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for div_result in eval_xpath(doc, '//div[@id="links"]/div[contains(@class, "web-result")]'):
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zero_click_info_xpath = '//html/body/form/div/table[2]/tr[2]/td/text()'
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item = {}
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title = eval_xpath(div_result, './/h2/a')
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if not title:
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# this is the "No results." item in the result list
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continue
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item["title"] = extract_text(title)
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item["url"] = eval_xpath(div_result, './/h2/a/@href')[0]
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item["content"] = extract_text(eval_xpath(div_result, './/a[contains(@class, "result__snippet")]')[0])
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results.append(item)
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zero_click_info_xpath = '//div[@id="zero_click_abstract"]'
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zero_click = extract_text(eval_xpath(doc, zero_click_info_xpath)).strip()
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if zero_click and "Your IP address is" not in zero_click and "Your user agent:" not in zero_click:
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@ -352,33 +389,6 @@ def response(resp):
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}
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)
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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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