[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  The old API suggestqueries.google.com/complete has been replaced
  by the async REST API: https://{subdomain}/complete/search?{args}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>

1 files changed, 24 insertions, 3 deletions

diff --git a/docs/src/searx.engines.google.rst b/docs/src/searx.engines.google.rst
index 2d10b5eea..9c15325f8 100644
--- a/docs/src/searx.engines.google.rst
+++ b/docs/src/searx.engines.google.rst
@@ -12,15 +12,21 @@ Google Engines
 
 .. _google API:
 
-google API
+Google API
 ==========
 
 .. _Query Parameter Definitions:
    https://developers.google.com/custom-search/docs/xml_results#WebSearch_Query_Parameter_Definitions
 
+SearXNG's implementation of the Google API is mainly done in
+:py:obj:`get_google_info <searx.engines.google.get_google_info>`.
+
 For detailed description of the *REST-full* API see: `Query Parameter
-Definitions`_.  Not all parameters can be appied and some engines are *special*
-(e.g. :ref:`google news engine`).
+Definitions`_.  The linked API documentation can sometimes be helpful during
+reverse engineering.  However, we cannot use it in the freely accessible WEB
+services; not all parameters can be applied and some engines are more *special*
+than other (e.g. :ref:`google news engine`).
+
 
 .. _google web engine:
 
@@ -30,6 +36,13 @@ Google WEB
 .. automodule:: searx.engines.google
   :members:
 
+.. _google autocomplete:
+
+Google Autocomplete
+====================
+
+.. autofunction:: searx.autocomplete.google_complete
+
 .. _google images engine:
 
 Google Images
@@ -53,3 +66,11 @@ Google News
 
 .. automodule:: searx.engines.google_news
   :members:
+
+.. _google scholar engine:
+
+Google Scholar
+==============
+
+.. automodule:: searx.engines.google_scholar
+  :members: