Don't crash if Colander is not installed

Cornices · Jan 16, 2016 · a5f3234 · a5f3234
1 parent acd4c33
commit a5f3234
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Showing 2 changed files with 29 additions and 9 deletions.
diff --git a/cornice/__init__.py b/cornice/__init__.py
@@ -15,6 +15,7 @@
     register_resource_views,
 )
 from cornice.util import ContentTypePredicate
+from pyramid.events import BeforeRender, NewRequest
 from pyramid.i18n import get_localizer
 from pyramid.httpexceptions import HTTPNotFound, HTTPForbidden
 from pyramid.security import NO_PERMISSION_REQUIRED
@@ -55,11 +56,32 @@ def set_localizer_for_languages(event, available_languages,
     request.localizer = localizer
 
 
+def setup_localization(config):
+    """
+    Setup localization based on the available_languages and
+    pyramid.default_locale_name settings.
+
+    These settings are named after suggestions from the "Internationalization
+    and Localization" section of the Pyramid documentation.
+    """
+    try:
+        config.add_translation_dirs('colander:locale/')
+        settings = config.get_settings()
+        available_languages = settings['available_languages'].split()
+        default_locale_name = settings.get('pyramid.default_locale_name', 'en')
+        set_localizer = partial(set_localizer_for_languages,
+                                available_languages=available_languages,
+                                default_locale_name=default_locale_name)
+        config.add_subscriber(set_localizer, NewRequest)
+    except ImportError:
+        # add_translation_dirs raises an ImportError if colander is not
+        # installed
+        pass
+
+
 def includeme(config):
     """Include the Cornice definitions
     """
-    from pyramid.events import BeforeRender, NewRequest
-
     # attributes required to maintain services
     config.registry.cornice_services = {}
 
@@ -85,10 +107,4 @@ def includeme(config):
                         permission=NO_PERMISSION_REQUIRED)
 
     if settings.get('available_languages'):
-        available_languages = settings['available_languages'].split()
-        default_locale_name = settings.get('pyramid.default_locale_name', 'en')
-        set_localizer = partial(set_localizer_for_languages,
-                                available_languages=available_languages,
-                                default_locale_name=default_locale_name)
-        config.add_subscriber(set_localizer, NewRequest)
-        config.add_translation_dirs('colander:locale/')
+        setup_localization(config)
diff --git a/docs/source/validation.rst b/docs/source/validation.rst
@@ -201,6 +201,10 @@ before passing the result to Colander.
 View-specific deserializers have priority over global content-type
 deserializers.
 
+To enable localization of Colander error messages, you must set
+`available_languages <http://docs.pylonsproject.org/projects/pyramid/en/1.3-branch/narr/i18n.html#detecting-available-languages>`_ in your settings.
+You may also set `pyramid.default_locale_name <http://docs.pylonsproject.org/projects/pyramid/en/1.3-branch/narr/environment.html#default-locale-name-setting>`_.
+
 
 Using formencode
 ~~~~~~~~~~~~~~~~