# SPDX-License-Identifier: AGPL-3.0-or-later
"""
DuckDuckGo Lite
~~~~~~~~~~~~~~~
"""
from typing import TYPE_CHECKING
import re
from urllib.parse import urlencode
import json
import babel
import lxml.html
from searx import (
locales,
redislib,
external_bang,
)
from searx.utils import (
eval_xpath,
extract_text,
)
from searx.network import get # see https://github.com/searxng/searxng/issues/762
from searx import redisdb
from searx.enginelib.traits import EngineTraits
from searx.utils import extr
from searx.exceptions import SearxEngineCaptchaException
if TYPE_CHECKING:
import logging
logger: logging.Logger
traits: EngineTraits
about = {
"website": 'https://lite.duckduckgo.com/lite/',
"wikidata_id": 'Q12805',
"use_official_api": False,
"require_api_key": False,
"results": 'HTML',
}
send_accept_language_header = True
"""DuckDuckGo-Lite tries to guess user's prefered language from the HTTP
``Accept-Language``. Optional the user can select a region filter (but not a
language).
"""
# engine dependent config
categories = ['general', 'web']
paging = True
time_range_support = True
safesearch = True # user can't select but the results are filtered
url = "https://html.duckduckgo.com/html"
time_range_dict = {'day': 'd', 'week': 'w', 'month': 'm', 'year': 'y'}
form_data = {'v': 'l', 'api': 'd.js', 'o': 'json'}
__CACHE = []
def _cache_key(data: dict):
return 'SearXNG_ddg_web_vqd' + redislib.secret_hash(f"{data['q']}//{data['kl']}")
[docs]
def cache_vqd(data: dict, value):
"""Caches a ``vqd`` value from a query."""
c = redisdb.client()
if c:
logger.debug("cache vqd value: %s", value)
c.set(_cache_key(data), value, ex=600)
else:
logger.debug("MEM cache vqd value: %s", value)
if len(__CACHE) > 100: # cache vqd from last 100 queries
__CACHE.pop(0)
__CACHE.append((_cache_key(data), value))
[docs]
def get_vqd(data):
"""Returns the ``vqd`` that fits to the *query* (``data`` from HTTP POST).
DDG's bot detection is sensitive to the ``vqd`` value. For some search terms
(such as extremely long search terms that are often sent by bots), no ``vqd``
value can be determined.
If SearXNG cannot determine a ``vqd`` value, then no request should go out
to DDG:
A request with a wrong ``vqd`` value leads to DDG temporarily putting
SearXNG's IP on a block list.
Requests from IPs in this block list run into timeouts.
Not sure, but it seems the block list is a sliding window: to get my IP rid
from the bot list I had to cool down my IP for 1h (send no requests from
that IP to DDG).
TL;DR; the ``vqd`` value is needed to pass DDG's bot protection and is used
by all request to DDG:
- DuckDuckGo Lite: ``https://lite.duckduckgo.com/lite`` (POST form data)
- DuckDuckGo Web: ``https://links.duckduckgo.com/d.js?q=...&vqd=...``
- DuckDuckGo Images: ``https://duckduckgo.com/i.js??q=...&vqd=...``
- DuckDuckGo Videos: ``https://duckduckgo.com/v.js??q=...&vqd=...``
- DuckDuckGo News: ``https://duckduckgo.com/news.js??q=...&vqd=...``
"""
key = _cache_key(data)
value = None
c = redisdb.client()
if c:
value = c.get(key)
if value or value == b'':
value = value.decode('utf-8')
logger.debug("re-use CACHED vqd value: %s", value)
return value
else:
for k, value in __CACHE:
if k == key:
logger.debug("MEM re-use CACHED vqd value: %s", value)
return value
return None
[docs]
def get_ddg_lang(eng_traits: EngineTraits, sxng_locale, default='en_US'):
"""Get DuckDuckGo's language identifier from SearXNG's locale.
DuckDuckGo defines its languages by region codes (see
:py:obj:`fetch_traits`).
To get region and language of a DDG service use:
.. code: python
eng_region = traits.get_region(params['searxng_locale'], traits.all_locale)
eng_lang = get_ddg_lang(traits, params['searxng_locale'])
It might confuse, but the ``l`` value of the cookie is what SearXNG calls
the *region*:
.. code:: python
# !ddi paris :es-AR --> {'ad': 'es_AR', 'ah': 'ar-es', 'l': 'ar-es'}
params['cookies']['ad'] = eng_lang
params['cookies']['ah'] = eng_region
params['cookies']['l'] = eng_region
.. hint::
`DDG-lite <https://lite.duckduckgo.com/lite>`__ and the *no Javascript*
page https://html.duckduckgo.com/html do not offer a language selection
to the user, only a region can be selected by the user (``eng_region``
from the example above). DDG-lite and *no Javascript* store the selected
region in a cookie::
params['cookies']['kl'] = eng_region # 'ar-es'
"""
return eng_traits.custom['lang_region'].get( # type: ignore
sxng_locale, eng_traits.get_language(sxng_locale, default)
)
ddg_reg_map = {
'tw-tzh': 'zh_TW',
'hk-tzh': 'zh_HK',
'ct-ca': 'skip', # ct-ca and es-ca both map to ca_ES
'es-ca': 'ca_ES',
'id-en': 'id_ID',
'no-no': 'nb_NO',
'jp-jp': 'ja_JP',
'kr-kr': 'ko_KR',
'xa-ar': 'ar_SA',
'sl-sl': 'sl_SI',
'th-en': 'th_TH',
'vn-en': 'vi_VN',
}
ddg_lang_map = {
# use ar --> ar_EG (Egypt's arabic)
"ar_DZ": 'lang_region',
"ar_JO": 'lang_region',
"ar_SA": 'lang_region',
# use bn --> bn_BD
'bn_IN': 'lang_region',
# use de --> de_DE
'de_CH': 'lang_region',
# use en --> en_US,
'en_AU': 'lang_region',
'en_CA': 'lang_region',
'en_GB': 'lang_region',
# Esperanto
'eo_XX': 'eo',
# use es --> es_ES,
'es_AR': 'lang_region',
'es_CL': 'lang_region',
'es_CO': 'lang_region',
'es_CR': 'lang_region',
'es_EC': 'lang_region',
'es_MX': 'lang_region',
'es_PE': 'lang_region',
'es_UY': 'lang_region',
'es_VE': 'lang_region',
# use fr --> rf_FR
'fr_CA': 'lang_region',
'fr_CH': 'lang_region',
'fr_BE': 'lang_region',
# use nl --> nl_NL
'nl_BE': 'lang_region',
# use pt --> pt_PT
'pt_BR': 'lang_region',
# skip these languages
'od_IN': 'skip',
'io_XX': 'skip',
'tokipona_XX': 'skip',
}
def quote_ddg_bangs(query):
# quote ddg bangs
query_parts = []
# for val in re.split(r'(\s+)', query):
for val in re.split(r'(\s+)', query):
if not val.strip():
continue
if val.startswith('!') and external_bang.get_node(external_bang.EXTERNAL_BANGS, val[1:]):
val = f"'{val}'"
query_parts.append(val)
return ' '.join(query_parts)
def request(query, params):
query = quote_ddg_bangs(query)
if len(query) >= 500:
# DDG does not accept queries with more than 499 chars
params["url"] = None
return
# Advanced search syntax ends in CAPTCHA
# https://duckduckgo.com/duckduckgo-help-pages/results/syntax/
query = " ".join(
[
x.removeprefix("site:").removeprefix("intitle:").removeprefix("inurl:").removeprefix("filetype:")
for x in query.split()
]
)
eng_region = traits.get_region(params['searxng_locale'], traits.all_locale)
if eng_region == "wt-wt":
# https://html.duckduckgo.com/html sets an empty value for "all".
eng_region = ""
params['data']['kl'] = eng_region
params['cookies']['kl'] = eng_region
# eng_lang = get_ddg_lang(traits, params['searxng_locale'])
params['url'] = url
params['method'] = 'POST'
params['data']['q'] = query
# The API is not documented, so we do some reverse engineering and emulate
# what https://html.duckduckgo.com/html does when you press "next Page" link
# again and again ..
params['headers']['Content-Type'] = 'application/x-www-form-urlencoded'
params['headers']['Sec-Fetch-Dest'] = "document"
params['headers']['Sec-Fetch-Mode'] = "navigate" # at least this one is used by ddg's bot detection
params['headers']['Sec-Fetch-Site'] = "same-origin"
params['headers']['Sec-Fetch-User'] = "?1"
# Form of the initial search page does have empty values in the form
if params['pageno'] == 1:
params['data']['b'] = ""
params['data']['df'] = ''
if params['time_range'] in time_range_dict:
params['data']['df'] = time_range_dict[params['time_range']]
params['cookies']['df'] = time_range_dict[params['time_range']]
if params['pageno'] == 2:
# second page does have an offset of 20
offset = (params['pageno'] - 1) * 20
params['data']['s'] = offset
params['data']['dc'] = offset + 1
elif params['pageno'] > 2:
# third and following pages do have an offset of 20 + n*50
offset = 20 + (params['pageno'] - 2) * 50
params['data']['s'] = offset
params['data']['dc'] = offset + 1
if params['pageno'] > 1:
# initial page does not have these additional data in the input form
params['data']['o'] = form_data.get('o', 'json')
params['data']['api'] = form_data.get('api', 'd.js')
params['data']['nextParams'] = form_data.get('nextParams', '')
params['data']['v'] = form_data.get('v', 'l')
params['headers']['Referer'] = url
# from here on no more params['data'] shuld be set, since this dict is
# needed to get a vqd value from the cache ..
vqd = get_vqd(params['data'])
# Certain conditions must be met in order to call up one of the
# following pages ...
if vqd:
params['data']['vqd'] = vqd # follow up pages / requests needs a vqd argument
else:
# Don't try to call follow up pages without a vqd value. DDG
# recognizes this as a request from a bot. This lowers the
# reputation of the SearXNG IP and DDG starts to activate CAPTCHAs.
params["url"] = None
return
if params['searxng_locale'].startswith("zh"):
# Some locales (at least China) do not have a "next page" button and ddg
# will return a HTTP/2 403 Forbidden for a request of such a page.
params["url"] = None
return
logger.debug("param data: %s", params['data'])
logger.debug("param cookies: %s", params['cookies'])
[docs]
def is_ddg_captcha(dom):
"""In case of CAPTCHA ddg response its own *not a Robot* dialog and is not
redirected to a CAPTCHA page."""
return bool(eval_xpath(dom, "//form[@id='challenge-form']"))
def response(resp):
if resp.status_code == 303:
return []
results = []
doc = lxml.html.fromstring(resp.text)
if is_ddg_captcha(doc):
# set suspend time to zero is OK --> ddg does not block the IP
raise SearxEngineCaptchaException(suspended_time=0, message=f"CAPTCHA ({resp.search_params['data'].get('kl')})")
form = eval_xpath(doc, '//input[@name="vqd"]/..')
if len(form):
# some locales (at least China) does not have a "next page" button
form = form[0]
form_vqd = eval_xpath(form, '//input[@name="vqd"]/@value')[0]
cache_vqd(resp.search_params["data"], form_vqd)
# just select "web-result" and ignore results of class "result--ad result--ad--small"
for div_result in eval_xpath(doc, '//div[@id="links"]/div[contains(@class, "web-result")]'):
item = {}
title = eval_xpath(div_result, './/h2/a')
if not title:
# this is the "No results." item in the result list
continue
item["title"] = extract_text(title)
item["url"] = eval_xpath(div_result, './/h2/a/@href')[0]
item["content"] = extract_text(eval_xpath(div_result, './/a[contains(@class, "result__snippet")]')[0])
results.append(item)
zero_click_info_xpath = '//div[@id="zero_click_abstract"]'
zero_click = extract_text(eval_xpath(doc, zero_click_info_xpath)).strip()
if zero_click and (
"Your IP address is" not in zero_click
and "Your user agent:" not in zero_click
and "URL Decoded:" not in zero_click
):
current_query = resp.search_params["data"].get("q")
results.append(
{
'answer': zero_click,
'url': "https://duckduckgo.com/?" + urlencode({"q": current_query}),
}
)
return results
[docs]
def fetch_traits(engine_traits: EngineTraits):
"""Fetch languages & regions from DuckDuckGo.
SearXNG's ``all`` locale maps DuckDuckGo's "Alle regions" (``wt-wt``).
DuckDuckGo's language "Browsers prefered language" (``wt_WT``) makes no
sense in a SearXNG request since SearXNG's ``all`` will not add a
``Accept-Language`` HTTP header. The value in ``engine_traits.all_locale``
is ``wt-wt`` (the region).
Beside regions DuckDuckGo also defines its languages by region codes. By
example these are the english languages in DuckDuckGo:
- en_US
- en_AU
- en_CA
- en_GB
The function :py:obj:`get_ddg_lang` evaluates DuckDuckGo's language from
SearXNG's locale.
"""
# pylint: disable=too-many-branches, too-many-statements, disable=import-outside-toplevel
from searx.utils import js_variable_to_python
# fetch regions
engine_traits.all_locale = 'wt-wt'
# updated from u661.js to u.7669f071a13a7daa57cb / should be updated automatically?
resp = get('https://duckduckgo.com/dist/util/u.7669f071a13a7daa57cb.js')
if not resp.ok: # type: ignore
print("ERROR: response from DuckDuckGo is not OK.")
js_code = extr(resp.text, 'regions:', ',snippetLengths')
regions = json.loads(js_code)
for eng_tag, name in regions.items():
if eng_tag == 'wt-wt':
engine_traits.all_locale = 'wt-wt'
continue
region = ddg_reg_map.get(eng_tag)
if region == 'skip':
continue
if not region:
eng_territory, eng_lang = eng_tag.split('-')
region = eng_lang + '_' + eng_territory.upper()
try:
sxng_tag = locales.region_tag(babel.Locale.parse(region))
except babel.UnknownLocaleError:
print("ERROR: %s (%s) -> %s is unknown by babel" % (name, eng_tag, region))
continue
conflict = engine_traits.regions.get(sxng_tag)
if conflict:
if conflict != eng_tag:
print("CONFLICT: babel %s --> %s, %s" % (sxng_tag, conflict, eng_tag))
continue
engine_traits.regions[sxng_tag] = eng_tag
# fetch languages
engine_traits.custom['lang_region'] = {}
js_code = extr(resp.text, 'languages:', ',regions')
languages = js_variable_to_python(js_code)
for eng_lang, name in languages.items():
if eng_lang == 'wt_WT':
continue
babel_tag = ddg_lang_map.get(eng_lang, eng_lang)
if babel_tag == 'skip':
continue
try:
if babel_tag == 'lang_region':
sxng_tag = locales.region_tag(babel.Locale.parse(eng_lang))
engine_traits.custom['lang_region'][sxng_tag] = eng_lang
continue
sxng_tag = locales.language_tag(babel.Locale.parse(babel_tag))
except babel.UnknownLocaleError:
print("ERROR: language %s (%s) is unknown by babel" % (name, eng_lang))
continue
conflict = engine_traits.languages.get(sxng_tag)
if conflict:
if conflict != eng_lang:
print("CONFLICT: babel %s --> %s, %s" % (sxng_tag, conflict, eng_lang))
continue
engine_traits.languages[sxng_tag] = eng_lang
