[mod] DuckDuckGo: reversed engineered & upgrade to data_type: traits_v1

Partial reverse engineering of the DuckDuckGo (DDG) engines including a
improved language and region handling based on the enigne.traits_v1 data.

- DDG Lite
- DDG Instant Answer API
- DDG Images
- DDG Weather

docs/src/searx.engine.duckduckgo.rst:
  Online documentation of the DDG engines (make docs.live)

searx/data/engine_traits.json
  Add data type "traits_v1" generated by the fetch_traits() functions from:

  - "duckduckgo" (WEB),
  - "duckduckgo images" and
  - "duckduckgo weather"

  and remove data from obsolete data type "supported_languages".

searx/autocomplete.py:
  Reversed engineered Autocomplete from DDG.  Supports DDG's languages.

searx/engines/duckduckgo.py:
  - fetch_traits():  Fetch languages & regions from DDG.

  - get_ddg_lang(): Get DDG's language identifier from SearXNG's locale.  DDG
    defines its languages by region codes.  DDG-Lite does not offer a language
    selection to the user, only a region can be selected by the user.

  - Cache ``vqd`` value: The vqd value depends on the query string and is needed
    for the follow up pages or the images loaded by a XMLHttpRequest (DDG
    images).  The ``vqd`` value of a search term is stored for 10min in the
    redis DB.

  - DDG Lite engine: reversed engineered request method with improved Language
    and region support and better ``vqd`` handling.

searx/engines/duckduckgo_definitions.py: DDG Instant Answer API
  The *instant answers* API does not support languages, or at least we could not
  find out how language support should work.  It seems that most of the features
  are based on English terms.

searx/engines/duckduckgo_images.py: DDG Images
  Reversed engineered request method.  Improved language and region handling
  based on cookies and the enigne.traits_v1 data.  Response: add image format to
  the result list

searx/engines/duckduckgo_weather.py: DDG Weather
  Improved language and region handling based on cookies and the
  enigne.traits_v1 data.

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

1 files changed, 55 insertions, 58 deletions

diff --git a/searx/engines/duckduckgo_images.py b/searx/engines/duckduckgo_images.py
index 927bc6cff..d8a6f1340 100644
--- a/searx/engines/duckduckgo_images.py
+++ b/searx/engines/duckduckgo_images.py
@@ -1,27 +1,30 @@
 # SPDX-License-Identifier: AGPL-3.0-or-later
 """
- DuckDuckGo (Images)
+DuckDuckGo Images
+~~~~~~~~~~~~~~~~~
 """
 
-from json import loads
+from typing import TYPE_CHECKING
 from urllib.parse import urlencode
-from searx.exceptions import SearxEngineAPIException
-from searx.engines.duckduckgo import get_region_code
-from searx.engines.duckduckgo import (  # pylint: disable=unused-import
-    fetch_traits,
-    _fetch_supported_languages,
-    supported_languages_url,
+
+from searx.engines.duckduckgo import fetch_traits  # pylint: disable=unused-import
+from searx.engines.duckduckgo import (
+    get_ddg_lang,
+    get_vqd,
 )
-from searx.network import get
+from searx.enginelib.traits import EngineTraits
+
+if TYPE_CHECKING:
+    import logging
+
+    logger: logging.Logger
+
+traits: EngineTraits
 
 # about
 about = {
     "website": 'https://duckduckgo.com/',
     "wikidata_id": 'Q12805',
-    "official_api_documentation": {
-        'url': 'https://duckduckgo.com/api',
-        'comment': 'but images are not supported',
-    },
     "use_official_api": False,
     "require_api_key": False,
     "results": 'JSON (site requires js to get images)',
@@ -33,70 +36,64 @@ paging = True
 safesearch = True
 send_accept_language_header = True
 
-# search-url
-images_url = 'https://duckduckgo.com/i.js?{query}&s={offset}&p={safesearch}&o=json&vqd={vqd}'
-site_url = 'https://duckduckgo.com/?{query}&iar=images&iax=1&ia=images'
+safesearch_cookies = {0: '-2', 1: None, 2: '1'}
+safesearch_args = {0: '1', 1: None, 2: '1'}
 
 
-# run query in site to get vqd number needed for requesting images
-# TODO: find a way to get this number without an extra request (is it a hash of the query?)
-def get_vqd(query, headers):
-    query_url = site_url.format(query=urlencode({'q': query}))
-    res = get(query_url, headers=headers)
-    content = res.text
-    if content.find('vqd=\'') == -1:
-        raise SearxEngineAPIException('Request failed')
-    vqd = content[content.find('vqd=\'') + 5 :]
-    vqd = vqd[: vqd.find('\'')]
-    return vqd
+def request(query, params):
 
+    eng_region = traits.get_region(params['searxng_locale'], traits.all_locale)
+    eng_lang = get_ddg_lang(traits, params['searxng_locale'])
 
-# do search-request
-def request(query, params):
-    # to avoid running actual external requests when testing
-    if 'is_test' not in params:
-        vqd = get_vqd(query, params['headers'])
-    else:
-        vqd = '12345'
+    args = {
+        'q': query,
+        'o': 'json',
+        # 'u': 'bing',
+        'l': eng_region,
+        'vqd': get_vqd(query, params["headers"]),
+    }
 
-    offset = (params['pageno'] - 1) * 50
+    if params['pageno'] > 1:
+        args['s'] = (params['pageno'] - 1) * 100
 
-    safesearch = params['safesearch'] - 1
+    params['cookies']['ad'] = eng_lang  # zh_CN
+    params['cookies']['ah'] = eng_region  # "us-en,de-de"
+    params['cookies']['l'] = eng_region  # "hk-tzh"
+    logger.debug("cookies: %s", params['cookies'])
 
-    region_code = get_region_code(params['language'], lang_list=supported_languages)
-    if region_code:
-        params['url'] = images_url.format(
-            query=urlencode({'q': query, 'l': region_code}), offset=offset, safesearch=safesearch, vqd=vqd
-        )
-    else:
-        params['url'] = images_url.format(query=urlencode({'q': query}), offset=offset, safesearch=safesearch, vqd=vqd)
+    safe_search = safesearch_cookies.get(params['safesearch'])
+    if safe_search is not None:
+        params['cookies']['p'] = safe_search  # "-2", "1"
+    safe_search = safesearch_args.get(params['safesearch'])
+    if safe_search is not None:
+        args['p'] = safe_search  # "-1", "1"
+
+    args = urlencode(args)
+    params['url'] = 'https://duckduckgo.com/i.js?{args}&f={f}'.format(args=args, f=',,,,,')
+
+    params['headers']['Accept'] = 'application/json, text/javascript, */*; q=0.01'
+    params['headers']['Referer'] = 'https://duckduckgo.com/'
+    params['headers']['X-Requested-With'] = 'XMLHttpRequest'
+    logger.debug("headers: %s", params['headers'])
 
     return params
 
 
-# get response from search-request
 def response(resp):
     results = []
+    res_json = resp.json()
 
-    content = resp.text
-    res_json = loads(content)
-
-    # parse results
     for result in res_json['results']:
-        title = result['title']
-        url = result['url']
-        thumbnail = result['thumbnail']
-        image = result['image']
-
-        # append result
         results.append(
             {
                 'template': 'images.html',
-                'title': title,
+                'title': result['title'],
                 'content': '',
-                'thumbnail_src': thumbnail,
-                'img_src': image,
-                'url': url,
+                'thumbnail_src': result['thumbnail'],
+                'img_src': result['image'],
+                'url': result['url'],
+                'img_format': '%s x %s' % (result['width'], result['height']),
+                'source': result['source'],
             }
         )