[mod] engines_languages.json: add new type engine_properties

This patch adds the boilerplate code, needed to fetch properties from engines.
In the past we only fetched *languages* but some engines need *regions* to
parameterize the engine request.

To fit into our *fetch language* procedures the boilerplate is implemented in
the `searxng_extra/update/update_languages.py` and the *engine_properties* are
stored along in the `searx/data/engines_languages.json`.

This implementation is downward compatible to the `_fetch_fetch_languages()`
infrastructure we have.  If there comes the day we have all
`_fetch_fetch_languages()` implementations moved to `_fetch_engine_properties()`
implementations, we can rename the files and scripts.

The new type `engine_properties` is a dictionary with keys `languages` and
`regions`.  The values are dictionaries to map from SearXNG's language & region
to option values the engine does use::

    engine_properties = {
        'type' : 'engine_properties',  # <-- !!!
        'regions': {
            # 'ca-ES' : <engine's region name>
        },
        'languages': {
            # 'ca' : <engine's language name>
        },
    }

Similar to the `supported_languages`, in the engine the properties are available
under the name `supported_properties`.

Initial we start with languages & regions, but in a wider sense the type is
named *engine properties*.  Engines can store in whatever options they need and
may be in the future there is a need to fetch additional or complete different
properties.

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

docs/admin/engines/configured_engines.rst

@@ -42,7 +42,7 @@ Explanation of the :ref:`general engine configuration` shown in the table
         - Timeout
         - Weight
         - Paging
-        - Language
+        - Language, Region
         - Safe search
         - Time range
 

manage

@@ -57,7 +57,7 @@ PYLINT_SEARXNG_DISABLE_OPTION="\
 I,C,R,\
 W0105,W0212,W0511,W0603,W0613,W0621,W0702,W0703,W1401,\
 E1136"
-PYLINT_ADDITIONAL_BUILTINS_FOR_ENGINES="supported_languages,language_aliases,logger,categories"
+PYLINT_ADDITIONAL_BUILTINS_FOR_ENGINES="supported_properties,supported_languages,language_aliases,logger,categories"
 PYLINT_OPTIONS="-m pylint -j 0 --rcfile .pylintrc"
 
 help() {

searx/autocomplete.py

@@ -15,7 +15,7 @@ from searx.data import ENGINES_LANGUAGES
 from searx.network import get as http_get
 from searx.exceptions import SearxEngineResponseException
 
-# a fetch_supported_languages() for XPath engines isn't available right now
+# a _fetch_supported_properites() for XPath engines isn't available right now
 # _brave = ENGINES_LANGUAGES['brave'].keys()
 
 

searx/engines/__init__.py

@@ -19,8 +19,7 @@ from os.path import realpath, dirname
 from babel.localedata import locale_identifiers
 from searx import logger, settings
 from searx.data import ENGINES_LANGUAGES
-from searx.network import get
-from searx.utils import load_module, match_language, gen_useragent
+from searx.utils import load_module, match_language
 
 
 logger = logger.getChild('engines')
@@ -36,8 +35,7 @@ ENGINE_DEFAULT_ARGS = {
     "timeout": settings["outgoing"]["request_timeout"],
     "shortcut": "-",
     "categories": ["general"],
-    "supported_languages": [],
-    "language_aliases": {},
+    "language_support" : False,
     "paging": False,
     "safesearch": False,
     "time_range_support": False,
@@ -58,10 +56,10 @@ class Engine:  # pylint: disable=too-few-public-methods
     engine: str
     shortcut: str
     categories: List[str]
-    supported_languages: List[str]
     about: dict
     inactive: bool
     disabled: bool
+    # language support, either by selecting a region or by selecting a language
     language_support: bool
     paging: bool
     safesearch: bool
@@ -143,6 +141,25 @@ def load_engine(engine_data: dict) -> Optional[Engine]:
 
     return engine
 
+def engine_properties_template():
+    """A dictionary with languages and regions to map from SearXNG' languages &
+    region tags to engine's language & region tags::
+
+      engine_properties = {
+          'type' : 'engine_properties',
+          'regions': {
+              # 'ca-ES' : <engine's region name>
+          },
+          'languages': {
+              # 'ca' : <engine's language name>
+          },
+      }
+    """
+    return {
+        'type' : 'engine_properties',
+        'regions': {},
+        'languages': {},
+    }
 
 def set_loggers(engine, engine_name):
     # set the logger for engine
@@ -179,8 +196,11 @@ def update_engine_attributes(engine: Engine, engine_data):
 
 def set_language_attributes(engine: Engine):
     # assign supported languages from json file
+
+    supported_properties = None
+
     if engine.name in ENGINES_LANGUAGES:
-        engine.supported_languages = ENGINES_LANGUAGES[engine.name]
+        supported_properties = ENGINES_LANGUAGES[engine.name]
 
     elif engine.engine in ENGINES_LANGUAGES:
         # The key of the dictionary ENGINES_LANGUAGES is the *engine name*
@@ -188,7 +208,20 @@ def set_language_attributes(engine: Engine):
         # settings.yml to use the same origin engine (python module) these
         # additional engines can use the languages from the origin engine.
         # For this use the configured ``engine: ...`` from settings.yml
-        engine.supported_languages = ENGINES_LANGUAGES[engine.engine]
+        supported_properties = ENGINES_LANGUAGES[engine.engine]
+
+    if not supported_properties:
+        return
+
+    if isinstance(supported_properties, dict) and supported_properties.get('type') == 'engine_properties':
+        engine.supported_properties = supported_properties
+        engine.language_support = len(supported_properties['languages']) or len(supported_properties['regions'])
+
+    else:
+        # depricated: does not work for engines that do support languages
+        # based on a region.
+        engine.supported_languages = supported_properties
+        engine.language_support = len(engine.supported_languages) > 0
 
         if hasattr(engine, 'language'):
             # For an engine, when there is `language: ...` in the YAML settings, the
@@ -205,6 +238,8 @@ def set_language_attributes(engine: Engine):
             else:
                 engine.supported_languages = [engine.language]
 
+        if not hasattr(engine, 'language_aliases'):
+            engine.language_aliases = {}
         # find custom aliases for non standard language codes
         for engine_lang in engine.supported_languages:
             iso_lang = match_language(engine_lang, BABEL_LANGS, fallback=None)
@@ -216,20 +251,6 @@ def set_language_attributes(engine: Engine):
             ):
                 engine.language_aliases[iso_lang] = engine_lang
 
-    # language_support
-    engine.language_support = len(engine.supported_languages) > 0
-
-    # assign language fetching method if auxiliary method exists
-    if hasattr(engine, '_fetch_supported_languages'):
-        headers = {
-            'User-Agent': gen_useragent(),
-            'Accept-Language': "en-US,en;q=0.5",  # bing needs to set the English language
-        }
-        engine.fetch_supported_languages = (
-            # pylint: disable=protected-access
-            lambda: engine._fetch_supported_languages(get(engine.supported_languages_url, headers=headers))
-        )
-
 
 def update_attributes_for_tor(engine: Engine) -> bool:
     if using_tor_proxy(engine) and hasattr(engine, 'onion_url'):

searx/engines/google_scholar.py

@@ -48,7 +48,6 @@ about = {
 # engine dependent config
 categories = ['science']
 paging = True
-language_support = True
 use_locale_domain = True
 time_range_support = True
 safesearch = False

searx/engines/google_videos.py

@@ -56,7 +56,6 @@ about = {
 
 categories = ['videos', 'web']
 paging = False
-language_support = True
 use_locale_domain = True
 time_range_support = True
 safesearch = True

searx/engines/yahoo_news.py

@@ -32,7 +32,6 @@ about = {
     "results": 'HTML',
 }
 
-language_support = False
 time_range_support = False
 safesearch = False
 paging = True

searx/engines/youtube_noapi.py

@@ -21,7 +21,6 @@ about = {
 # engine dependent config
 categories = ['videos', 'music']
 paging = True
-language_support = False
 time_range_support = True
 
 # search-url

searxng_extra/update/update_languages.py

@@ -1,14 +1,29 @@
 #!/usr/bin/env python
 # lint: pylint
-
 # SPDX-License-Identifier: AGPL-3.0-or-later
-"""This script generates languages.py from intersecting each engine's supported
-languages.
+"""This script generates :origin:`searx/languages.py` from intersecting each
+engine's supported properites. The script checks all engines about a function::
+
+  def _fetch_engine_properties(resp, engine_properties):
+      ...
+
+and a variable named ``supported_properties_url``.  The HTTP get response of
+``supported_properties_url`` is passed to the ``_fetch_engine_properties``
+function including a template of ``engine_properties`` (see
+:py:obj:`searx.engines.engine_properties_template`).
 
 Output files: :origin:`searx/data/engines_languages.json` and
 :origin:`searx/languages.py` (:origin:`CI Update data ...
 <.github/workflows/data-update.yml>`).
 
+.. hint::
+
+  This implementation is backward compatible and supports the (depricated)
+  ``_fetch_supported_languages`` interface.
+
+  On the long term the depricated implementations in the engines will be
+  replaced by ``_fetch_engine_properties``.
+
 """
 
 # pylint: disable=invalid-name
@@ -21,32 +36,67 @@ from babel.languages import get_global
 from babel.core import parse_locale
 
 from searx import settings, searx_dir
-from searx.engines import load_engines, engines
-from searx.network import set_timeout_for_thread
+from searx import network
+from searx.engines import load_engines, engines, engine_properties_template
+from searx.utils import gen_useragent
 
 # Output files.
 engines_languages_file = Path(searx_dir) / 'data' / 'engines_languages.json'
 languages_file = Path(searx_dir) / 'languages.py'
 
 
-# Fetchs supported languages for each engine and writes json file with those.
 def fetch_supported_languages():
-    set_timeout_for_thread(10.0)
+    """Fetchs supported languages for each engine and writes json file with those.
 
+    """
+    network.set_timeout_for_thread(10.0)
     engines_languages = {}
     names = list(engines)
     names.sort()
 
+    # The headers has been moved here from commit 9b6ffed06: Some engines (at
+    # least bing and startpage) return a different result list of supported
+    # languages depending on the IP location where the HTTP request comes from.
+    # The IP based results (from bing) can be avoided by setting a
+    # 'Accept-Language' in the HTTP request.
+
+    headers = {
+        'User-Agent': gen_useragent(),
+        'Accept-Language': "en-US,en;q=0.5",  # bing needs to set the English language
+    }
+
     for engine_name in names:
-        if hasattr(engines[engine_name], 'fetch_supported_languages'):
-            engines_languages[engine_name] = engines[engine_name].fetch_supported_languages()
-            print("fetched %s languages from engine %s" % (len(engines_languages[engine_name]), engine_name))
-            if type(engines_languages[engine_name]) == list:  # pylint: disable=unidiomatic-typecheck
-                engines_languages[engine_name] = sorted(engines_languages[engine_name])
+        engine = engines[engine_name]
+        fetch_languages = getattr(engine, '_fetch_supported_languages', None)
+        fetch_properties = getattr(engine, '_fetch_engine_properties', None)
 
-    print("fetched languages from %s engines" % len(engines_languages))
+        if fetch_properties is not None:
+            resp = network.get(engine.supported_properties_url, headers=headers)
+            engine_properties = engine_properties_template()
+            fetch_properties(resp, engine_properties)
+            print("%s: %s languages" % (engine_name, len(engine_properties['languages'])))
+            print("%s: %s regions" % (engine_name, len(engine_properties['regions'])))
+
+        elif fetch_languages is not None:
+            # print("%s: using deepricated _fetch_fetch_languages()" % engine_name)
+            resp = network.get(engine.supported_languages_url, headers=headers)
+            engine_properties = fetch_languages(resp)
+            if isinstance(engine_properties, list):
+                engine_properties.sort()
+
+            print("%s: fetched language %s containing %s items" % (
+                engine_name,
+                engine_properties.__class__.__name__,
+                len(engine_properties)
+            ))
+        else:
+            continue
+
+        engines_languages[engine_name] = engine_properties
+
+    print("fetched properties from %s engines" % len(engines_languages))
+    print("write json file: %s" % (engines_languages_file))
 
-    # write json file
     with open(engines_languages_file, 'w', encoding='utf-8') as f:
         json.dump(engines_languages, f, indent=2, sort_keys=True)
 
@@ -122,17 +172,33 @@ def get_territory_name(lang_code):
         print("ERROR: %s --> %s" % (locale, exc))
     return country_name
 
-
-# Join all language lists.
 def join_language_lists(engines_languages):
+    """Join all languages of the engines into one list.  The returned language list
+    contains language codes (``zh``) and region codes (``zh-TW``).  The codes can
+    be parsed by babel::
+
+      babel.Locale.parse(language_list[n])
+
+    """
+    # pylint: disable=too-many-branches
     language_list = {}
+
     for engine_name in engines_languages:
-        for lang_code in engines_languages[engine_name]:
+        engine = engines[engine_name]
+        engine_codes = languages = engines_languages[engine_name]
+
+        if isinstance(languages, dict):
+            engine_codes = languages.get('regions', engine_codes)
+
+        if isinstance(engine_codes, dict):
+            engine_codes = engine_codes.keys()
+
+        for lang_code in engine_codes:
 
             # apply custom fixes if necessary
-            if lang_code in getattr(engines[engine_name], 'language_aliases', {}).values():
+            if lang_code in getattr(engine, 'language_aliases', {}).values():
                 lang_code = next(
-                    lc for lc, alias in engines[engine_name].language_aliases.items() if lang_code == alias
+                    lc for lc, alias in engine.language_aliases.items() if lang_code == alias
                 )
 
             locale = get_locale(lang_code)
@@ -197,6 +263,7 @@ def filter_language_list(all_languages):
         engine_name
         for engine_name in engines.keys()
         if 'general' in engines[engine_name].categories
+        and hasattr(engines[engine_name], 'supported_languages')
         and engines[engine_name].supported_languages
         and not engines[engine_name].disabled
     ]