[#959] add ITranslations interface

This allows extensions to merge in their own translations with the main
ckan mo file. Each extension should have an 'i18n' directory in the root
directory of their repo containing its translations. The gettext domain
(and hence filename) of the .mo files should be ckanext-{extname}

ckan/lib/i18n.py

@@ -2,10 +2,14 @@
 
 from babel import Locale, localedata
 from babel.core import LOCALE_ALIASES
+from babel.support import Translations
 from pylons import config
 from pylons import i18n
+import pylons
 
 import ckan.i18n
+from ckan.plugins import PluginImplementations
+from ckan.plugins.interfaces import ITranslations
 
 LOCALE_ALIASES['pt'] = 'pt_BR' # Default Portuguese language to
                                # Brazilian territory, since
@@ -121,9 +125,17 @@ def _set_lang(lang):
     if config.get('ckan.i18n_directory'):
         fake_config = {'pylons.paths': {'root': config['ckan.i18n_directory']},
                        'pylons.package': config['pylons.package']}
-        i18n.set_lang(lang, pylons_config=fake_config)
+        i18n.set_lang(lang, pylons_config=fake_config, class_=Translations)
     else:
-        i18n.set_lang(lang)
+        i18n.set_lang(lang, class_=Translations)
+
+    for plugin in PluginImplementations(ITranslations):
+        pylons.translator.merge(Translations.load(
+            dirname=plugin.directory(),
+            locales=plugin.locales(),
+            domain=plugin.domain()
+        ))
+
 
 def handle_request(request, tmpl_context):
     ''' Set the language for the request '''

ckan/lib/plugins.py

@@ -524,3 +524,31 @@ def activity_template(self):
         return 'organization/activity_stream.html'
 
 _default_organization_plugin = DefaultOrganizationForm()
+
+
+class DefaultTranslation(object):
+    def directory(self):
+        '''Change the directory of the *.mo translation files
+
+        The default implementation assumes the plugin is
+        ckanext/myplugin/plugin.py and the translations are stored in
+        i18n/
+        '''
+        import os
+        return os.path.abspath(os.path.join(os.path.dirname(__file__),
+                                            '../../', 'i18n'))
+    def locales(self):
+        '''Change the list of locales that this plugin handles
+
+        By default the will assume any directory in subdirectory returned
+        by self.directory() is a locale handled by this plugin
+        '''
+        import os
+        directory = self.directory()
+        return [ d for
+                 d in os.listdir(directory)
+                 if os.path.isdir(os.path.join(directory, d))
+        ]
+
+    def domain(self):
+        return 'ckanext-{name}'.format(name=self.name)

ckan/plugins/interfaces.py

@@ -22,6 +22,7 @@
     'ITemplateHelpers',
     'IFacets',
     'IAuthenticator',
+    'ITranslations',
 ]
 
 from inspect import isclass
@@ -1432,3 +1433,22 @@ def abort(self, status_code, detail, headers, comment):
         '''called on abort.  This allows aborts due to authorization issues
         to be overriden'''
         return (status_code, detail, headers, comment)
+
+
+class ITranslations(Interface):
+    def directory(self):
+        '''Change the directory of the *.mo translation files
+
+        The default implementation assumes the plugin is
+        ckanext/myplugin/plugin.py and the translations are stored in
+        i18n/
+        '''
+    def locales(self):
+        '''Change the list of locales that this plugin handles
+
+        By default the will assume any directory in subdirectory returned
+        by self.directory() is a locale handled by this plugin
+        '''
+
+    def domain(self):
+        '''Change the gettext domain handled by this plugin'''