mediagoblin/tools/translate.py

   1 # GNU MediaGoblin -- federated, autonomous media hosting
   2 # Copyright (C) 2011, 2012 MediaGoblin contributors.  See AUTHORS.
   3 #
   4 # This program is free software: you can redistribute it and/or modify
   5 # it under the terms of the GNU Affero General Public License as published by
   6 # the Free Software Foundation, either version 3 of the License, or
   7 # (at your option) any later version.
   8 #
   9 # This program is distributed in the hope that it will be useful,
  10 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 # GNU Affero General Public License for more details.
  13 #
  14 # You should have received a copy of the GNU Affero General Public License
  15 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 import gettext
  18 import pkg_resources
  19
  20
  21 from babel import localedata
  22 from babel.support import LazyProxy
  23
  24 from mediagoblin import mg_globals
  25
  26 ###################
  27 # Translation tools
  28 ###################
  29
  30 AVAILABLE_LOCALES = None
  31 TRANSLATIONS_PATH = pkg_resources.resource_filename(
  32     'mediagoblin', 'i18n')
  33
  34
  35 def set_available_locales():
  36     """Set available locales for which we have translations"""
  37     global AVAILABLE_LOCALES
  38     locales=['en', 'en_US'] # these are available without translations
  39     for locale in localedata.list():
  40         if gettext.find('mediagoblin', TRANSLATIONS_PATH, [locale]):
  41             locales.append(locale)
  42     AVAILABLE_LOCALES = locales
  43
  44
  45 class ReallyLazyProxy(LazyProxy):
  46     """
  47     Like LazyProxy, except that it doesn't cache the value ;)
  48     """
  49     @property
  50     def value(self):
  51         return self._func(*self._args, **self._kwargs)
  52
  53     def __repr__(self):
  54         return "<%s for %s(%r, %r)>" % (
  55             self.__class__.__name__,
  56             self._func,
  57             self._args,
  58             self._kwargs)
  59
  60
  61 def locale_to_lower_upper(locale):
  62     """
  63     Take a locale, regardless of style, and format it like "en_US"
  64     """
  65     if '-' in locale:
  66         lang, country = locale.split('-', 1)
  67         return '%s_%s' % (lang.lower(), country.upper())
  68     elif '_' in locale:
  69         lang, country = locale.split('_', 1)
  70         return '%s_%s' % (lang.lower(), country.upper())
  71     else:
  72         return locale.lower()
  73
  74
  75 def locale_to_lower_lower(locale):
  76     """
  77     Take a locale, regardless of style, and format it like "en_us"
  78     """
  79     if '_' in locale:
  80         lang, country = locale.split('_', 1)
  81         return '%s-%s' % (lang.lower(), country.lower())
  82     else:
  83         return locale.lower()
  84
  85
  86 def get_locale_from_request(request):
  87     """
  88     Return most appropriate language based on prefs/request request
  89     """
  90     request_args = (request.args, request.form)[request.method=='POST']
  91
  92     if 'lang' in request_args:
  93         # User explicitely demanded a language, normalize lower_uppercase
  94         target_lang = locale_to_lower_upper(request_args['lang'])
  95
  96     elif 'target_lang' in request.session:
  97         # TODO: Uh, ohh, this is never ever set anywhere?
  98         target_lang = request.session['target_lang']
  99     else:
 100         # Pull the most acceptable language based on browser preferences
 101         # This returns one of AVAILABLE_LOCALES which is aready case-normalized.
 102         # Note: in our tests request.accept_languages is None, so we need
 103         # to explicitely fallback to en here.
 104         target_lang = request.accept_languages.best_match(AVAILABLE_LOCALES) \
 105                       or "en_US"
 106
 107     return target_lang
 108
 109 SETUP_GETTEXTS = {}
 110
 111 def get_gettext_translation(locale):
 112     """
 113     Return the gettext instance based on this locale
 114     """
 115     # Later on when we have plugins we may want to enable the
 116     # multi-translations system they have so we can handle plugin
 117     # translations too
 118
 119     # TODO: fallback nicely on translations from pt_PT to pt if not
 120     # available, etc.
 121     if locale in SETUP_GETTEXTS:
 122         this_gettext = SETUP_GETTEXTS[locale]
 123     else:
 124         this_gettext = gettext.translation(
 125             'mediagoblin', TRANSLATIONS_PATH, [locale], fallback=True)
 126         if localedata.exists(locale):
 127             SETUP_GETTEXTS[locale] = this_gettext
 128     return this_gettext
 129
 130
 131 def set_thread_locale(locale):
 132     """Set the current translation for this thread"""
 133     mg_globals.thread_scope.translations = get_gettext_translation(locale)
 134
 135
 136 def pass_to_ugettext(*args, **kwargs):
 137     """
 138     Pass a translation on to the appropriate ugettext method.
 139
 140     The reason we can't have a global ugettext method is because
 141     mg_globals gets swapped out by the application per-request.
 142     """
 143     return mg_globals.thread_scope.translations.ugettext(
 144         *args, **kwargs)
 145
 146 def pass_to_ungettext(*args, **kwargs):
 147     """
 148     Pass a translation on to the appropriate ungettext method.
 149
 150     The reason we can't have a global ugettext method is because
 151     mg_globals gets swapped out by the application per-request.
 152     """
 153     return mg_globals.thread_scope.translations.ungettext(
 154         *args, **kwargs)
 155
 156
 157 def lazy_pass_to_ugettext(*args, **kwargs):
 158     """
 159     Lazily pass to ugettext.
 160
 161     This is useful if you have to define a translation on a module
 162     level but you need it to not translate until the time that it's
 163     used as a string. For example, in:
 164         def func(self, message=_('Hello boys and girls'))
 165
 166     you would want to use the lazy version for _.
 167     """
 168     return ReallyLazyProxy(pass_to_ugettext, *args, **kwargs)
 169
 170
 171 def pass_to_ngettext(*args, **kwargs):
 172     """
 173     Pass a translation on to the appropriate ngettext method.
 174
 175     The reason we can't have a global ngettext method is because
 176     mg_globals gets swapped out by the application per-request.
 177     """
 178     return mg_globals.thread_scope.translations.ngettext(
 179         *args, **kwargs)
 180
 181
 182 def lazy_pass_to_ngettext(*args, **kwargs):
 183     """
 184     Lazily pass to ngettext.
 185
 186     This is useful if you have to define a translation on a module
 187     level but you need it to not translate until the time that it's
 188     used as a string.
 189     """
 190     return ReallyLazyProxy(pass_to_ngettext, *args, **kwargs)
 191
 192 def lazy_pass_to_ungettext(*args, **kwargs):
 193     """
 194     Lazily pass to ungettext.
 195
 196     This is useful if you have to define a translation on a module
 197     level but you need it to not translate until the time that it's
 198     used as a string.
 199     """
 200     return ReallyLazyProxy(pass_to_ungettext, *args, **kwargs)
 201
 202
 203 def fake_ugettext_passthrough(string):
 204     """
 205     Fake a ugettext call for extraction's sake ;)
 206
 207     In wtforms there's a separate way to define a method to translate
 208     things... so we just need to mark up the text so that it can be
 209     extracted, not so that it's actually run through gettext.
 210     """
 211     return string