Honor user's browser language (#558)

Previously we would attempt to satisfy the user's first language
preference, immediately falling back to english if that was not
possible. Now, we will get the best match of the user's preferred
languages.

This requires storing the available locales on app startup, so we
have mg_globals.available_locales ready to compare them against the
list of preferred user languages.

Signed-off-by: Sebastian Spaeth <Sebastian@SSpaeth.de>

mediagoblin/app.py

@@ -31,7 +31,7 @@ from mediagoblin.mg_globals import setup_globals
 from mediagoblin.init.celery import setup_celery_from_config
 from mediagoblin.init.plugins import setup_plugins
 from mediagoblin.init import (get_jinja_loader, get_staticdirector,
-    setup_global_and_app_config, setup_workbench, setup_database,
+    setup_global_and_app_config, setup_locales, setup_workbench, setup_database,
     setup_storage, setup_beaker_cache)
 from mediagoblin.tools.pluginapi import PluginManager
 
@@ -68,6 +68,9 @@ class MediaGoblinApp(object):
         # Setup other connections / useful objects
         ##########################################
 
+        # load all available locales
+        setup_locales()
+
         # Set up plugins -- need to do this early so that plugins can
         # affect startup.
         _log.info("Setting up plugins.")

mediagoblin/init/__init__.py

@@ -19,6 +19,7 @@ from beaker.util import parse_cache_config_options
 import jinja2
 
 from mediagoblin.tools import staticdirect
+from mediagoblin.tools.translate import get_available_locales
 from mediagoblin.init.config import (
     read_mediagoblin_config, generate_validation_report)
 from mediagoblin import mg_globals
@@ -37,6 +38,11 @@ class ImproperlyConfigured(Error):
     pass
 
 
+def setup_locales():
+    """Checks which language translations are available and sets them"""
+    setup_globals(available_locales=get_available_locales())
+
+
 def setup_global_and_app_config(config_path):
     global_config, validation_result = read_mediagoblin_config(config_path)
     app_config = global_config['mediagoblin']

mediagoblin/mg_globals.py

@@ -45,6 +45,8 @@ workbench_manager = None
 # A thread-local scope
 thread_scope = threading.local()
 
+# a list of translated locales
+available_locales = None
 # gettext (this will be populated on demand with gettext.Translations)
 thread_scope.translations = None
 

mediagoblin/tools/template.py

@@ -20,7 +20,7 @@ from babel.localedata import exists
 from mediagoblin import mg_globals
 from mediagoblin import messages
 from mediagoblin.tools import common
-from mediagoblin.tools.translate import setup_gettext
+from mediagoblin.tools.translate import get_gettext_translation
 from mediagoblin.meddleware.csrf import render_csrf_form_token
 
 
@@ -34,7 +34,7 @@ def get_jinja_env(template_loader, locale):
     (In the future we may have another system for providing theming;
     for now this is good enough.)
     """
-    setup_gettext(locale)
+    mg_globals.thread_scope.translations = get_gettext_translation(locale)
 
     # If we have a jinja environment set up with this locale, just
     # return that one.

mediagoblin/tools/translate.py

@@ -16,7 +16,9 @@
 
 import gettext
 import pkg_resources
-from babel.localedata import exists
+
+
+from babel import localedata
 from babel.support import LazyProxy
 
 from mediagoblin import mg_globals
@@ -30,6 +32,15 @@ TRANSLATIONS_PATH = pkg_resources.resource_filename(
     'mediagoblin', 'i18n')
 
 
+def get_available_locales():
+    """Return a list of locales for which we have translations"""
+    locales=[]
+    for locale in localedata.list():
+        if gettext.find('mediagoblin', TRANSLATIONS_PATH, [locale]):
+            locales.append(locale)
+    return locales
+
+
 def locale_to_lower_upper(locale):
     """
     Take a locale, regardless of style, and format it like "en_US"
@@ -76,15 +87,15 @@ def get_locale_from_request(request):
         # TODO: We need a list of available locales, and match with the list
         # of accepted locales, and serve the best available locale rather than
         # the most preferred, or fall back to 'en' immediately.
-        target_lang = request.accept_languages.best
-
-    return locale_to_lower_upper(target_lang)
+        target_lang = request.accept_languages.best_match(
+            mg_globals.available_locales)
+        return locale_to_lower_upper(target_lang)
 
 SETUP_GETTEXTS = {}
 
-def setup_gettext(locale):
+def get_gettext_translation(locale):
     """
-    Setup the gettext instance based on this locale
+    Return the gettext instance based on this locale
     """
     # Later on when we have plugins we may want to enable the
     # multi-translations system they have so we can handle plugin
@@ -97,10 +108,9 @@ def setup_gettext(locale):
     else:
         this_gettext = gettext.translation(
             'mediagoblin', TRANSLATIONS_PATH, [locale], fallback=True)
-        if exists(locale):
+        if localedata.exists(locale):
             SETUP_GETTEXTS[locale] = this_gettext
-
-    mg_globals.thread_scope.translations = this_gettext
+    return this_gettext
 
 
 def pass_to_ugettext(*args, **kwargs):