- New public interface: ``repoze.bfg.exceptions.IExceptionResponse``.

  This interface is provided by all internal exception classes (such
  as ``repoze.bfg.exceptions.NotFound`` and
  ``repoze.bfg.exceptions.Forbidden``), instances of which are both
  exception objects and can behave as WSGI response objects.  This
  interface is made public so that exception classes which are also
  valid WSGI response factories can be configured to implement them
  or exception instances which are also or response instances can be
  configured to provide them.

- New API class: ``repoze.bfg.view.AppendSlashNotFoundViewFactory`` (undoes 
  previous custom_notfound_view on request passsed to 
  append_slash_notfound_view).

- Previously, two default view functions were registered at
  Configurator setup (one for ``repoze.bfg.exceptions.NotFound`` named
  ``default_notfound_view`` and one for
  ``repoze.bfg.exceptions.Forbidden`` named
  ``default_forbidden_view``) to render internal exception responses.
  Those default view functions have been removed, replaced with a
  generic default view function which is registered at Configurator
  setup for the ``repoze.bfg.interfaces.IExceptionResponse`` interface
  that simply returns the exception instance; the ``NotFound` and
  ``Forbidden`` classes are now still exception factories but they are
  also response factories which generate instances that implement the
  new ``repoze.bfg.interfaces.IExceptionResponse`` interface.

1 files changed, 11 insertions, 6 deletions

diff --git a/repoze/bfg/configuration.py b/repoze/bfg/configuration.py
index f694d7737..0ab4abcb5 100644
--- a/repoze/bfg/configuration.py
+++ b/repoze/bfg/configuration.py
@@ -38,6 +38,8 @@ from repoze.bfg.interfaces import ITranslationDirectories
 from repoze.bfg.interfaces import ITraverser
 from repoze.bfg.interfaces import IView
 from repoze.bfg.interfaces import IViewClassifier
+from repoze.bfg.interfaces import IExceptionResponse
+from repoze.bfg.interfaces import IException
 
 from repoze.bfg import chameleon_text
 from repoze.bfg import chameleon_zpt
@@ -69,8 +71,7 @@ from repoze.bfg.traversal import DefaultRootFactory
 from repoze.bfg.traversal import find_interface
 from repoze.bfg.urldispatch import RoutesMapper
 from repoze.bfg.view import render_view_to_response
-from repoze.bfg.view import default_notfound_view
-from repoze.bfg.view import default_forbidden_view
+from repoze.bfg.view import default_exceptionresponse_view
 
 MAX_ORDER = 1 << 30
 DEFAULT_PHASH = md5().hexdigest()
@@ -408,8 +409,8 @@ class Configurator(object):
                                         authorization_policy)
         for name, renderer in renderers:
             self.add_renderer(name, renderer)
-        self.add_view(default_notfound_view, context=NotFound)
-        self.add_view(default_forbidden_view, context=Forbidden)
+        self.add_view(default_exceptionresponse_view,
+                      context=IExceptionResponse)
         if locale_negotiator:
             registry.registerUtility(locale_negotiator, ILocaleNegotiator)
         if request_factory:
@@ -2312,8 +2313,12 @@ def _attr_wrap(view, accept, order, phash):
     return attr_view
 
 def isexception(o):
-    return isinstance(o, Exception) or (
-        inspect.isclass(o) and issubclass(o, Exception)
+    if IInterface.providedBy(o):
+        if IException.isEqualOrExtendedBy(o):
+            return True
+    return (
+        isinstance(o, Exception) or
+        (inspect.isclass(o) and (issubclass(o, Exception)))
         )
 
 # note that ``options`` is a b/w compat alias for ``settings`` and