[fix] duckduckgo extra: crashes and returns no results

searx/engines/duckduckgo.py

@@ -6,7 +6,7 @@ DuckDuckGo Lite
 
 from typing import TYPE_CHECKING
 import re
-from urllib.parse import urlencode
+from urllib.parse import urlencode, quote_plus
 import json
 import babel
 import lxml.html
@@ -18,12 +18,12 @@ from searx import (
 )
 from searx.utils import (
     eval_xpath,
+    extr,
     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:
@@ -60,25 +60,25 @@ form_data = {'v': 'l', 'api': 'd.js', 'o': 'json'}
 __CACHE = []
 
 
-def _cache_key(data: dict):
+def _cache_key(query, region):
-    return 'SearXNG_ddg_web_vqd' + redislib.secret_hash(f"{data['q']}//{data['kl']}")
+    return 'SearXNG_ddg_web_vqd' + redislib.secret_hash(f"{query}//{region}")
 
 
-def cache_vqd(data: dict, value):
+def cache_vqd(query, region, 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)
+        c.set(_cache_key(query, region), 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))
+        __CACHE.append((_cache_key(query, region), value))
 
 
-def get_vqd(data):
+def get_vqd(query, region):
     """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
@@ -108,7 +108,7 @@ def get_vqd(data):
 
     """
 
-    key = _cache_key(data)
+    key = _cache_key(query, region)
     value = None
     c = redisdb.client()
     if c:
@@ -126,6 +126,23 @@ def get_vqd(data):
     return None
 
 
+def extract_vqd(query):
+    """
+    Scrape the vqd value matching the query from DuckDuckGo Web.
+    That function is currently not required for general results,
+    only for extra results such as images, videos, ...
+
+    Also see ``get_vqd(query, region)`` above.
+    """
+    resp = get(f'https://duckduckgo.com/?q={quote_plus(query)}')
+    if resp.status_code != 200:
+        return None
+
+    vqd = extr(resp.text, 'vqd="', '"')
+
+    return vqd
+
+
 def get_ddg_lang(eng_traits: EngineTraits, sxng_locale, default='en_US'):
     """Get DuckDuckGo's language identifier from SearXNG's locale.
 
@@ -313,7 +330,7 @@ def request(query, params):
         # 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'])
+        vqd = get_vqd(query, eng_region)
 
         # Certain conditions must be met in order to call up one of the
         # following pages ...
@@ -362,7 +379,7 @@ def response(resp):
         form = form[0]
         form_vqd = eval_xpath(form, '//input[@name="vqd"]/@value')[0]
 
-        cache_vqd(resp.search_params["data"], form_vqd)
+        cache_vqd(resp.search_params['data']['q'], resp.search_params['data']['kl'], 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")]'):

searx/engines/duckduckgo_extra.py

@@ -11,6 +11,8 @@ from searx.utils import get_embeded_stream_url
 
 from searx.engines.duckduckgo import fetch_traits  # pylint: disable=unused-import
 from searx.engines.duckduckgo import (
+    cache_vqd,
+    extract_vqd,
     get_ddg_lang,
     get_vqd,
 )
@@ -48,15 +50,20 @@ search_path_map = {'images': 'i', 'videos': 'v', 'news': 'news'}
 
 
 def request(query, params):
+    eng_region = traits.get_region(params['searxng_locale'], traits.all_locale)
 
     # request needs a vqd argument
-    vqd = get_vqd(query)
+    vqd = get_vqd(query, eng_region)
+    if not vqd:
+        vqd = extract_vqd(query)
+        if vqd:
+            cache_vqd(query, eng_region, vqd)
+
     if not vqd:
         # some search terms do not have results and therefore no vqd value
         params['url'] = None
         return params
 
-    eng_region = traits.get_region(params['searxng_locale'], traits.all_locale)
     eng_lang = get_ddg_lang(traits, params['searxng_locale'])
 
     args = {
@@ -86,6 +93,12 @@ def request(query, params):
 
     params['url'] = f'https://duckduckgo.com/{search_path_map[ddg_category]}.js?{urlencode(args)}'
 
+    # sending these two headers prevents rate limiting for the query
+    params['headers'] = {
+        'Referer': 'https://duckduckgo.com/',
+        'X-Requested-With': 'XMLHttpRequest',
+    }
+
     return params