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

Partial reverse engineering of the Google engines including a improved language
and region handling based on the engine.traits_v1 data.

When ever possible the implementations of the Google engines try to make use of
the async REST APIs.  The get_lang_info() has been generalized to a
get_google_info() function / especially the region handling has been improved by
adding the cr parameter.

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

  - Google (WEB),
  - Google images,
  - Google news,
  - Google scholar and
  - Google videos

  and remove data from obsolete data type "supported_languages".

  A traits.custom type that maps region codes to *supported_domains* is fetched
  from https://www.google.com/supported_domains

searx/autocomplete.py:
  Reversed engineered autocomplete from Google WEB.  Supports Google's languages and
  subdomains.  The old API suggestqueries.google.com/complete has been replaced
  by the async REST API: https://{subdomain}/complete/search?{args}

searx/engines/google.py
  Reverse engineering and extensive testing ..
  - fetch_traits():  Fetch languages & regions from Google properties.
  - always use the async REST API (formally known as 'use_mobile_ui')
  - use *supported_domains* from traits
  - improved the result list by fetching './/div[@data-content-feature]'
    and parsing the type of the various *content features* --> thumbnails are
    added

searx/engines/google_images.py
  Reverse engineering and extensive testing ..
  - fetch_traits():  Fetch languages & regions from Google properties.
  - use *supported_domains* from traits
  - if exists, freshness_date is added to the result
  - issue 1864: result list has been improved a lot (due to the new cr parameter)

searx/engines/google_news.py
  Reverse engineering and extensive testing ..
  - fetch_traits():  Fetch languages & regions from Google properties.
    *supported_domains* is not needed but a ceid list has been added.
  - different region handling compared to Google WEB
  - fixed for various languages & regions (due to the new ceid parameter) /
    avoid CONSENT page
  - Google News do no longer support time range
  - result list has been fixed: XPath of pub_date and pub_origin

searx/engines/google_videos.py
  - fetch_traits():  Fetch languages & regions from Google properties.
  - use *supported_domains* from traits
  - add paging support
  - implement a async request ('asearch': 'arc' & 'async':
    'use_ac:true,_fmt:html')
  - simplified code (thanks to '_fmt:html' request)
  - issue 1359: fixed xpath of video length data

searx/engines/google_scholar.py
  - fetch_traits():  Fetch languages & regions from Google properties.
  - use *supported_domains* from traits
  - request(): include patents & citations
  - response(): fixed CAPTCHA detection (Scholar has its own CATCHA manager)
  - hardening XPath to iterate over results
  - fixed XPath of pub_type (has been change from gs_ct1 to gs_cgt2 class)
  - issue 1769 fixed: new request implementation is no longer incompatible

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

searx/autocomplete.py

@@ -5,14 +5,17 @@
 """
 # pylint: disable=use-dict-literal
 
-from json import loads
+import json
 from urllib.parse import urlencode
 
-from lxml import etree
+import lxml
 from httpx import HTTPError
 
 from searx import settings
-from searx.engines import engines
+from searx.engines import (
+    engines,
+    google,
+)
 from searx.network import get as http_get
 from searx.exceptions import SearxEngineResponseException
 
@@ -55,7 +58,7 @@ def dbpedia(query, _lang):
     results = []
 
     if response.ok:
-        dom = etree.fromstring(response.content)
+        dom = lxml.etree.fromstring(response.content)
         results = dom.xpath('//Result/Label//text()')
 
     return results
@@ -81,18 +84,32 @@ def duckduckgo(query, sxng_locale):
     return ret_val
 
 
-def google(query, lang):
-    # google autocompleter
-    autocomplete_url = 'https://suggestqueries.google.com/complete/search?client=toolbar&'
+def google_complete(query, sxng_locale):
+    """Autocomplete from Google.  Supports Google's languages and subdomains
+    (:py:obj:`searx.engines.google.get_google_info`) by using the async REST
+    API::
 
-    response = get(autocomplete_url + urlencode(dict(hl=lang, q=query)))
+        https://{subdomain}/complete/search?{args}
 
+    """
+
+    google_info = google.get_google_info({'searxng_locale': sxng_locale}, engines['google'].traits)
+
+    url = 'https://{subdomain}/complete/search?{args}'
+    args = urlencode(
+        {
+            'q': query,
+            'client': 'gws-wiz',
+            'hl': google_info['params']['hl'],
+        }
+    )
     results = []
-
-    if response.ok:
-        dom = etree.fromstring(response.text)
-        results = dom.xpath('//suggestion/@data')
-
+    resp = get(url.format(subdomain=google_info['subdomain'], args=args))
+    if resp.ok:
+        json_txt = resp.text[resp.text.find('[') : resp.text.find(']', -3) + 1]
+        data = json.loads(json_txt)
+        for item in data[0]:
+            results.append(lxml.html.fromstring(item[0]).text_content())
     return results
 
 
@@ -132,7 +149,7 @@ def swisscows(query, _lang):
     # swisscows autocompleter
     url = 'https://swisscows.ch/api/suggest?{query}&itemsCount=5'
 
-    resp = loads(get(url.format(query=urlencode({'query': query}))).text)
+    resp = json.loads(get(url.format(query=urlencode({'query': query}))).text)
     return resp
 
 
@@ -184,7 +201,7 @@ def yandex(query, _lang):
     # yandex autocompleter
     url = "https://suggest.yandex.com/suggest-ff.cgi?{0}"
 
-    resp = loads(get(url.format(urlencode(dict(part=query)))).text)
+    resp = json.loads(get(url.format(urlencode(dict(part=query)))).text)
     if len(resp) > 1:
         return resp[1]
     return []
@@ -193,7 +210,7 @@ def yandex(query, _lang):
 backends = {
     'dbpedia': dbpedia,
     'duckduckgo': duckduckgo,
-    'google': google,
+    'google': google_complete,
     'seznam': seznam,
     'startpage': startpage,
     'swisscows': swisscows,