[mod] engine duckduckgo - use DuckDuckGo-Lite

Implement a scrapper for DuckDuckGo-Lite [1].  The existing DuckDuckGo [2]
engine does not support paging.  DuckDuckgo-Lite is much faster, less verbose
and does have a paging option (reversed engineered from the input form of [1]).

[1] https://lite.duckduckgo.com/lite
[2] https://duckduckgo.com/

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>
This commit is contained in:
Markus Heiser 2021-09-30 16:40:00 +02:00
parent 62ea3c7074
commit 4c9b8b29ee

View File

@ -1,16 +1,24 @@
# SPDX-License-Identifier: AGPL-3.0-or-later
"""
DuckDuckGo (Web)
# lint: pylint
"""DuckDuckGo Lite
"""
from lxml.html import fromstring
from json import loads
from searx.utils import extract_text, match_language, eval_xpath, dict_subset
from lxml.html import fromstring
from searx.utils import (
dict_subset,
eval_xpath,
eval_xpath_getindex,
extract_text,
match_language,
)
from searx.network import get
# about
about = {
"website": 'https://duckduckgo.com/',
"website": 'https://lite.duckduckgo.com/lite',
"wikidata_id": 'Q12805',
"official_api_documentation": 'https://duckduckgo.com/api',
"use_official_api": False,
@ -20,7 +28,7 @@ about = {
# engine dependent config
categories = ['general']
paging = False
paging = True
supported_languages_url = 'https://duckduckgo.com/util/u172.js'
time_range_support = True
@ -34,21 +42,16 @@ language_aliases = {
'zh-HK': 'tzh-HK'
}
time_range_dict = {
'day': 'd',
'week': 'w',
'month': 'm',
'year': 'y'
}
# search-url
url = 'https://html.duckduckgo.com/html'
url_ping = 'https://duckduckgo.com/t/sl_h'
time_range_dict = {'day': 'd',
'week': 'w',
'month': 'm',
'year': 'y'}
# specific xpath variables
result_xpath = '//div[@class="result results_links results_links_deep web-result "]' # noqa
url_xpath = './/a[@class="result__a"]/@href'
title_xpath = './/a[@class="result__a"]'
content_xpath = './/a[@class="result__snippet"]'
correction_xpath = '//div[@id="did_you_mean"]//a'
url = 'https://lite.duckduckgo.com/lite'
url_ping = 'https://duckduckgo.com/t/sl_l'
# match query's language to a region code that duckduckgo will accept
def get_region_code(lang, lang_list=None):
@ -63,66 +66,111 @@ def get_region_code(lang, lang_list=None):
def request(query, params):
if params['time_range'] is not None and params['time_range'] not in time_range_dict:
return params
params['url'] = url
params['method'] = 'POST'
params['data']['q'] = query
params['data']['b'] = ''
# The API is not documented, so we do some reverse engineering and emulate
# what https://lite.duckduckgo.com/lite/ does when you press "next Page"
# link again and again ..
params['headers']['Content-Type'] = 'application/x-www-form-urlencoded'
# initial page does not have an offset
if params['pageno'] == 2:
# second page does have an offset of 30
offset = (params['pageno'] - 1) * 30
params['data']['s'] = offset
params['data']['dc'] = offset + 1
elif params['pageno'] > 2:
# third and following pages do have an offset of 30 + n*50
offset = 30 + (params['pageno'] - 2) * 50
params['data']['s'] = offset
params['data']['dc'] = offset + 1
# initial page does not have additional data in the input form
if params['pageno'] > 1:
# request the second page (and more pages) needs 'o' and 'api' arguments
params['data']['o'] = 'json'
params['data']['api'] = 'd.js'
# initial page does not have additional data in the input form
if params['pageno'] > 2:
# request the third page (and more pages) some more arguments
params['data']['nextParams'] = ''
params['data']['v'] = ''
params['data']['vqd'] = ''
region_code = get_region_code(params['language'], supported_languages)
if region_code:
params['data']['kl'] = region_code
params['cookies']['kl'] = region_code
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']]
params['allow_redirects'] = False
logger.debug("param data: %s", params['data'])
logger.debug("param cookies: %s", params['cookies'])
return params
# get response from search-request
def response(resp):
if resp.status_code == 303:
return []
# ping
headers_ping = dict_subset(resp.request.headers, ['User-Agent', 'Accept-Encoding', 'Accept', 'Cookie'])
get(url_ping, headers=headers_ping)
# parse the response
if resp.status_code == 303:
return []
results = []
doc = fromstring(resp.text)
for i, r in enumerate(eval_xpath(doc, result_xpath)):
if i >= 30:
break
try:
res_url = eval_xpath(r, url_xpath)[-1]
except:
result_table = eval_xpath(doc, '//html/body/form/div[@class="filters"]/table')
if not len(result_table) >= 3:
# no more results
return []
result_table = result_table[2]
tr_rows = eval_xpath(result_table, './/tr')
# In the last <tr> is the form of the 'previous/next page' links
tr_rows = tr_rows[:-1]
len_tr_rows = len(tr_rows)
offset = 0
while len_tr_rows >= offset + 4:
# assemble table rows we need to scrap
tr_title = tr_rows[offset]
tr_content = tr_rows[offset + 1]
offset += 4
# ignore sponsored Adds <tr class="result-sponsored">
if tr_content.get('class') == 'result-sponsored':
continue
if not res_url:
a_tag = eval_xpath_getindex(tr_title, './/td//a[@class="result-link"]', 0, None)
if a_tag is None:
continue
title = extract_text(eval_xpath(r, title_xpath))
content = extract_text(eval_xpath(r, content_xpath))
td_content = eval_xpath_getindex(tr_content, './/td[@class="result-snippet"]', 0, None)
if td_content is None:
continue
# append result
results.append({'title': title,
'content': content,
'url': res_url})
results.append({
'title': a_tag.text_content(),
'content': extract_text(td_content),
'url': a_tag.get('href'),
})
# parse correction
for correction in eval_xpath(doc, correction_xpath):
# append correction
results.append({'correction': extract_text(correction)})
# return results
return results
# get supported languages from their site
def _fetch_supported_languages(resp):