[mod] replace utils.match_language by locales.match_locale

This patch replaces the *full of magic* ``utils.match_language`` function by a
``locales.match_locale``.  The ``locales.match_locale`` function is based on the
``locales.build_engine_locales`` introduced in 9ae409a0 [1].

In the past SearXNG did only support a search by a language but not in a region.
This has been changed a long time ago and regions have been added to SearXNG
core but not to the engines.  The ``utils.match_language`` was the function to
handle the different aspects of language/regions in SearXNG core and the
supported *languages* in the engine.  The ``utils.match_language`` did it with
some magic and works good for most use cases but fails in some edge case.

To replace the concurrence of languages and regions in the SearXNG core the
``locales.build_engine_locales`` was introduced in 9ae409a0 [1].  With the last
patches all engines has been migrated to a ``fetch_traits`` and a
language/region concept that is based on ``locales.build_engine_locales``.

To summarize: there is no longer a need for the ``locales.match_language``.

[1] https://github.com/searxng/searxng/pull/1652

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

1 files changed, 0 insertions, 88 deletions

diff --git a/searx/utils.py b/searx/utils.py
index f7a71b649..161983011 100644
--- a/searx/utils.py
+++ b/searx/utils.py
@@ -18,8 +18,6 @@ from urllib.parse import urljoin, urlparse
 
 from lxml import html
 from lxml.etree import ElementBase, XPath, XPathError, XPathSyntaxError, _ElementStringResult, _ElementUnicodeResult
-from babel.core import get_global
-
 
 from searx import settings
 from searx.data import USER_AGENTS, data_dir
@@ -365,92 +363,6 @@ def is_valid_lang(lang) -> Optional[Tuple[bool, str, str]]:
     return None
 
 
-def _get_lang_to_lc_dict(lang_list: List[str]) -> Dict[str, str]:
-    key = str(lang_list)
-    value = _LANG_TO_LC_CACHE.get(key, None)
-    if value is None:
-        value = {}
-        for lang in lang_list:
-            value.setdefault(lang.split('-')[0], lang)
-        _LANG_TO_LC_CACHE[key] = value
-    return value
-
-
-# babel's get_global contains all sorts of miscellaneous locale and territory related data
-# see get_global in: https://github.com/python-babel/babel/blob/master/babel/core.py
-def _get_from_babel(lang_code: str, key):
-    match = get_global(key).get(lang_code.replace('-', '_'))
-    # for some keys, such as territory_aliases, match may be a list
-    if isinstance(match, str):
-        return match.replace('_', '-')
-    return match
-
-
-def _match_language(lang_code: str, lang_list=[], custom_aliases={}) -> Optional[str]:  # pylint: disable=W0102
-    """auxiliary function to match lang_code in lang_list"""
-    # replace language code with a custom alias if necessary
-    if lang_code in custom_aliases:
-        lang_code = custom_aliases[lang_code]
-
-    if lang_code in lang_list:
-        return lang_code
-
-    # try to get the most likely country for this language
-    subtags = _get_from_babel(lang_code, 'likely_subtags')
-    if subtags:
-        if subtags in lang_list:
-            return subtags
-        subtag_parts = subtags.split('-')
-        new_code = subtag_parts[0] + '-' + subtag_parts[-1]
-        if new_code in custom_aliases:
-            new_code = custom_aliases[new_code]
-        if new_code in lang_list:
-            return new_code
-
-    # try to get the any supported country for this language
-    return _get_lang_to_lc_dict(lang_list).get(lang_code)
-
-
-def match_language(  # pylint: disable=W0102
-    locale_code, lang_list=[], custom_aliases={}, fallback: Optional[str] = 'en-US'
-) -> Optional[str]:
-    """get the language code from lang_list that best matches locale_code"""
-    # try to get language from given locale_code
-    language = _match_language(locale_code, lang_list, custom_aliases)
-    if language:
-        return language
-
-    locale_parts = locale_code.split('-')
-    lang_code = locale_parts[0]
-
-    # if locale_code has script, try matching without it
-    if len(locale_parts) > 2:
-        language = _match_language(lang_code + '-' + locale_parts[-1], lang_list, custom_aliases)
-        if language:
-            return language
-
-    # try to get language using an equivalent country code
-    if len(locale_parts) > 1:
-        country_alias = _get_from_babel(locale_parts[-1], 'territory_aliases')
-        if country_alias:
-            language = _match_language(lang_code + '-' + country_alias[0], lang_list, custom_aliases)
-            if language:
-                return language
-
-    # try to get language using an equivalent language code
-    alias = _get_from_babel(lang_code, 'language_aliases')
-    if alias:
-        language = _match_language(alias, lang_list, custom_aliases)
-        if language:
-            return language
-
-    if lang_code != locale_code:
-        # try to get language from given language without giving the country
-        language = _match_language(lang_code, lang_list, custom_aliases)
-
-    return language or fallback
-
-
 def load_module(filename: str, module_dir: str) -> types.ModuleType:
     modname = splitext(filename)[0]
     modpath = join(module_dir, filename)