Fix locale and search language

Locale and search language was always defined with english value.

This patch inits the locale on `pre_request` in order to define the
default value of locale and language preferences.

Plus the `best_match` function provided by flask babel library did not
work as expected. So the function `match_language` provided
by searx is used to detect that the language from Accepted-Language
header can be used in searx project.

searx/preferences.py

@@ -243,8 +243,8 @@ class Preferences(object):
         super(Preferences, self).__init__()
 
         self.key_value_settings = {'categories': MultipleChoiceSetting(['general'], choices=categories + ['none']),
-                                   'language': SearchLanguageSetting(settings['search']['language'],
+                                   'language': SearchLanguageSetting(settings['ui']['default_locale'],
-                                                                     choices=LANGUAGE_CODES),
+                                                                     choices=list(LANGUAGE_CODES) + ['']),
                                    'locale': EnumStringSetting(settings['ui']['default_locale'],
                                                                choices=list(settings['locales'].keys()) + ['']),
                                    'autocomplete': EnumStringSetting(settings['search']['autocomplete'],

searx/settings.yml

@@ -5,7 +5,6 @@ general:
 search:
     safe_search : 0 # Filter results. 0: None, 1: Moderate, 2: Strict
     autocomplete : "" # Existing autocomplete backends: "dbpedia", "duckduckgo", "google", "startpage", "wikipedia" - leave blank to turn it off by default
-    language : "en-US"
     ban_time_on_fail : 5 # ban time in seconds after engine errors
     max_ban_time_on_fail : 120 # max ban time in seconds after engine errors
 

searx/webapp.py

@@ -152,7 +152,14 @@ outgoing_proxies = settings['outgoing'].get('proxies') or None
 
 @babel.localeselector
 def get_locale():
-    locale = request.accept_languages.best_match(settings['locales'].keys())
+    locale = "en-US"
+
+    for lang in request.headers.get("Accept-Language", locale).split(","):
+        locale = match_language(lang, settings['locales'].keys(), fallback=None)
+        if locale is not None:
+            break
+
+    logger.debug("default locale from browser info is `%s`", locale)
 
     if request.preferences.get_value('locale') != '':
         locale = request.preferences.get_value('locale')
@@ -164,6 +171,8 @@ def get_locale():
     if locale == 'zh_TW':
         locale = 'zh_Hant_TW'
 
+    logger.debug("selected locale is `%s`", locale)
+
     return locale
 
 
@@ -342,7 +351,9 @@ def render(template_name, override_theme=None, **kwargs):
     if 'autocomplete' not in kwargs:
         kwargs['autocomplete'] = request.preferences.get_value('autocomplete')
 
-    if get_locale() in rtl_locales and 'rtl' not in kwargs:
+    locale = request.preferences.get_value('locale')
+
+    if locale in rtl_locales and 'rtl' not in kwargs:
         kwargs['rtl'] = True
 
     kwargs['searx_version'] = VERSION_STRING
@@ -355,7 +366,7 @@ def render(template_name, override_theme=None, **kwargs):
     if 'current_language' not in kwargs:
         kwargs['current_language'] = match_language(request.preferences.get_value('language'),
                                                     LANGUAGE_CODES,
-                                                    fallback=settings['search']['language'])
+                                                    fallback=locale)
 
     # override url_for function in templates
     kwargs['url_for'] = url_for_theme
@@ -423,6 +434,13 @@ def pre_request():
             logger.exception('invalid settings')
             request.errors.append(gettext('Invalid settings'))
 
+    # init search language and locale
+    locale = get_locale()
+    if not preferences.get_value("language"):
+        preferences.parse_dict({"language": locale})
+    if not preferences.get_value("locale"):
+        preferences.parse_dict({"locale": locale})
+
     # request.user_plugins
     request.user_plugins = []
     allowed_plugins = preferences.plugins.get_enabled()
@@ -593,7 +611,7 @@ def index():
         unresponsive_engines=result_container.unresponsive_engines,
         current_language=match_language(search_query.lang,
                                         LANGUAGE_CODES,
-                                        fallback=settings['search']['language']),
+                                        fallback=request.preferences.get_value("language")),
         base_url=get_base_url(),
         theme=get_current_theme_name(),
         favicons=global_favicons[themes.index(get_current_theme_name())]
@@ -702,7 +720,7 @@ def preferences():
 
     return render('preferences.html',
                   locales=settings['locales'],
-                  current_locale=get_locale(),
+                  current_locale=request.preferences.get_value("locale"),
                   image_proxy=image_proxy,
                   engines_by_category=categories,
                   stats=stats,