bug 1399639: Use locale name for statici18n path

django-statici18n is now using the locale name, such as en_US, rather
than the standardized language code, like en-US. Replace that dash with
an underscore, and update some utility functions to be clear about
locale names versus language codes (which may be important as we retire
the custom locale middleware).

kuma/core/templatetags/jinja_helpers.py

@@ -14,11 +14,11 @@
 from django_jinja import library
 from pytz import timezone, utc
 from soapbox.models import Message
-from statici18n.templatetags.statici18n import statici18n
+from statici18n.templatetags.statici18n import statici18n as lib_statici18n
 from urlobject import URLObject
 
 from ..urlresolvers import reverse, split_path
-from ..utils import format_date_time, urlparams
+from ..utils import format_date_time, language_to_locale, urlparams
 
 
 htmlparser = HTMLParser.HTMLParser()
@@ -29,8 +29,6 @@
 library.filter(defaultfilters.linebreaksbr)
 library.filter(strip_tags)
 library.filter(defaultfilters.truncatewords)
-library.global_function(statici18n)
-
 library.filter(urlparams)
 
 
@@ -40,6 +38,13 @@ def paginator(pager):
     return Paginator(pager).render()
 
 
+@library.global_function
+def statici18n(language):
+    """Get path to JS i18n file by Kuma langugage code."""
+    locale = language_to_locale(language)
+    return lib_statici18n(locale)
+
+
 @library.global_function
 def url(viewname, *args, **kwargs):
     """Helper for Django's ``reverse`` in templates."""

kuma/core/utils.py

@@ -393,17 +393,16 @@ def format_date_time(request, value, format='shortdatetime'):
     except AttributeError:
         pass
 
-    locale = _babel_locale(_get_request_locale(request))
+    locale = _get_request_locale(request)
 
     try:
         formatted = format_date_value(value, tzvalue, locale, format)
     except KeyError:
         # Babel sometimes stumbles over missing formatters in some locales
         # e.g. bug #1247086
         # we fall back formatting the value with the default language code
-        formatted = format_date_value(value, tzvalue,
-                                      _babel_locale(settings.LANGUAGE_CODE),
-                                      format)
+        formatted = format_date_value(
+            value, tzvalue, language_to_locale(settings.LANGUAGE_CODE), format)
 
     return formatted, tzvalue
 
@@ -413,7 +412,7 @@ def _get_request_locale(request):
     locale = request.LANGUAGE_CODE
     if not localedata.exists(locale):
         locale = settings.LANGUAGE_CODE
-    return locale
+    return language_to_locale(locale)
 
 
 def format_date_value(value, tzvalue, locale, format):
@@ -439,7 +438,14 @@ def format_date_value(value, tzvalue, locale, format):
         raise DateTimeFormatError
 
 
-def _babel_locale(locale):
-    """Return the Babel locale code, given a normal one."""
-    # Babel uses underscore as separator.
-    return locale.replace('-', '_')
+def language_to_locale(language_code):
+    """
+    Convert language codes to locale names used by Babel, Django
+
+    Kuma uses a dash for regions, like en-US, zh-CN.
+    Babel and Django use underscore, like en_US, zh_CN.
+    The codes are identical when there is no region, like fr, es.
+
+    https://docs.djangoproject.com/en/1.11/topics/i18n/#definitions
+    """
+    return language_code.replace('-', '_')