From 74d56f6cfb0dc8e30a6d4f95cce09937984cda2d Mon Sep 17 00:00:00 2001
From: Alexandre Flament <alex@al-f.net>
Date: Tue, 9 Feb 2021 14:33:36 +0100
Subject: [PATCH 1/2] [mod] poolrequests: for one (user request, engine) always
 use the same HTTPAdapter

The duckduckgo engine requires an additional request after the results have been sent.
This commit makes sure that the second request uses the same HTTPAdapter
= the same IP address, and the same proxy.
---
 searx/poolrequests.py | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/searx/poolrequests.py b/searx/poolrequests.py
index 25a6baed..8b868143 100644
--- a/searx/poolrequests.py
+++ b/searx/poolrequests.py
@@ -1,7 +1,7 @@
 import sys
 from time import time
 from itertools import cycle
-from threading import RLock, local
+from threading import local
 
 import requests
 
@@ -88,10 +88,12 @@ class SessionSinglePool(requests.Session):
         super().__init__()
 
         # reuse the same adapters
-        with RLock():
-            self.adapters.clear()
-            self.mount('https://', next(https_adapters))
-            self.mount('http://', next(http_adapters))
+        self.adapters.clear()
+
+        https_adapter = threadLocal.__dict__.setdefault('https_adapter', next(https_adapters))
+        http_adapter = threadLocal.__dict__.setdefault('http_adapter', next(http_adapters))
+        self.mount('https://', https_adapter)
+        self.mount('http://', http_adapter)
 
     def close(self):
         """Call super, but clear adapters since there are managed globaly"""

From d2dac11392c89084e8d6143f09c27c5fefabdef9 Mon Sep 17 00:00:00 2001
From: Alexandre Flament <alex@al-f.net>
Date: Tue, 9 Feb 2021 14:36:43 +0100
Subject: [PATCH 2/2] [mod] duckduckgo engine: better support of the language
 preference

After the main request, send a second to https://duckduckgo.com/t/sl_h

See https://github.com/searx/searx/issues/2259
---
 searx/engines/duckduckgo.py | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/searx/engines/duckduckgo.py b/searx/engines/duckduckgo.py
index 7f137826..638f1211 100644
--- a/searx/engines/duckduckgo.py
+++ b/searx/engines/duckduckgo.py
@@ -5,7 +5,8 @@
 
 from lxml.html import fromstring
 from json import loads
-from searx.utils import extract_text, match_language, eval_xpath
+from searx.utils import extract_text, match_language, eval_xpath, dict_subset
+from searx.poolrequests import get
 
 # about
 about = {
@@ -35,6 +36,7 @@ language_aliases = {
 
 # 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'}
@@ -65,27 +67,27 @@ def request(query, params):
 
     params['url'] = url
     params['method'] = 'POST'
-    params['data']['b'] = ''
     params['data']['q'] = query
-    params['data']['df'] = ''
+    params['data']['b'] = ''
 
     region_code = get_region_code(params['language'], supported_languages)
     if region_code:
         params['data']['kl'] = region_code
         params['cookies']['kl'] = region_code
-    if params['time_range'] in time_range_dict:
-        params['data']['df'] = time_range_dict[params['time_range']]
 
+    params['data']['df'] = time_range_dict.get(params['time_range'], '')
     return params
 
 
 # get response from search-request
 def response(resp):
+    # ping
+    headers_ping = dict_subset(resp.request.headers, ['User-Agent', 'Accept-Encoding', 'Accept', 'Cookie'])
+    get(url_ping, headers=headers_ping)
+
+    # parse the response
     results = []
-
     doc = fromstring(resp.text)
-
-    # parse results
     for i, r in enumerate(eval_xpath(doc, result_xpath)):
         if i >= 30:
             break