Integrate Zope 3-based exception views. Patch by Sidnei, integration

work done for Infrae.

doc/CHANGES.txt

@@ -100,6 +100,27 @@ Zope Changes
       - AccessControl: the form behind the "Security" tab has a new form
         for user-related reporting of permissions and roles
 
+      - Zope 3-based exception views can now be registered in ZCML for
+        various exceptions that can be raised by Zope. Registering an
+        exception view can be done like this:
+
+          <browser:page
+            for="zope.publisher.interfaces.INotFound"
+            class=".view.SomeView"
+            name="index.html"
+            permission="zope.Public" />
+
+        Relevant exceptions that can have views are:
+
+        zope.interface.common.interfaces.IException
+        zope.publisher.interfaces.INotFound
+        zope.security.interfaces.IForbidden
+        zope.security.interfaces.IUnauthorized
+
+        Note that the name has to be 'index.html' for the exception
+        view to work. (patch by Sidnei da Silva from Enfold,
+        integration by Martijn Faassen (Startifact) for Infrae)
+
     Bugs Fixed
 
       - Collector #1306: Missing acquisition context on local roles screen.

lib/python/Zope2/App/startup.py

@@ -13,6 +13,7 @@
 """Initialize the Zope2 Package and provide a published module
 """
 
+from zope.component import queryMultiAdapter
 from AccessControl.SecurityManagement import getSecurityManager
 from AccessControl.SecurityManagement import newSecurityManager
 from AccessControl.SecurityManagement import noSecurityManager
@@ -20,7 +21,7 @@ from Acquisition import aq_acquire
 from App.config import getConfiguration
 from time import asctime
 from types import StringType, ListType
-from zExceptions import Unauthorized
+from zExceptions import Unauthorized, Redirect
 from ZODB.POSException import ConflictError
 import transaction
 import AccessControl.User
@@ -37,6 +38,8 @@ import App.ZApplication
 import Zope2
 import ZPublisher
 
+app = None
+startup_time = asctime()
 
 def startup():
     global app
@@ -138,35 +141,45 @@ def validated_hook(request, user):
 class RequestContainer(ExtensionClass.Base):
     def __init__(self,r): self.REQUEST=r
 
-conflict_errors = 0
-unresolved_conflict_errors = 0
-
-conflict_logger = logging.getLogger('ZPublisher.Conflict')
+class ZPublisherExceptionHook:
+
+    def __init__(self):
+        self.conflict_errors = 0
+        self.unresolved_conflict_errors = 0
+        self.conflict_logger = logging.getLogger('ZPublisher.Conflict')
+        self.error_message = 'standard_error_message'
+        self.raise_error_message = 'raise_standardErrorMessage'
+
+    def logConflicts(self, v, REQUEST):
+        self.conflict_errors += 1
+        level = getattr(getConfiguration(), 'conflict_error_log_level', 0)
+        if not self.conflict_logger.isEnabledFor(level):
+            return False
+        self.conflict_logger.log(
+            level,
+            "%s at %s: %s (%d conflicts (%d unresolved) "
+            "since startup at %s)",
+            v.__class__.__name__,
+            REQUEST.get('PATH_INFO', '<unknown>'),
+            v,
+            self.conflict_errors,
+            self.unresolved_conflict_errors,
+            startup_time)
+        return True
 
-def zpublisher_exception_hook(published, REQUEST, t, v, traceback):
-    global unresolved_conflict_errors
-    global conflict_errors
+    def __call__(self, published, REQUEST, t, v, traceback):
         try:
             if isinstance(t, StringType):
                 if t.lower() in ('unauthorized', 'redirect'):
                     raise
             else:
-            if t is SystemExit:
+                if t is SystemExit or t is Redirect:
                     raise
+
                 if issubclass(t, ConflictError):
-                conflict_errors += 1
-                level = getConfiguration().conflict_error_log_level
-                if level:
-                    conflict_logger.log(level,
-                        "%s at %s: %s (%d conflicts (%d unresolved) "
-                        "since startup at %s)",
-                        v.__class__.__name__,
-                        REQUEST.get('PATH_INFO', '<unknown>'),
-                        v,
-                        conflict_errors,
-                        unresolved_conflict_errors,
-                        startup_time)
+                    self.logConflicts(v, REQUEST)
                     raise ZPublisher.Retry(t, v, traceback)
+
                 if t is ZPublisher.Retry:
                     try:
                         v.reraise()
@@ -177,7 +190,7 @@ def zpublisher_exception_hook(published, REQUEST, t, v, traceback):
                         t, v, traceback = sys.exc_info()
                     if issubclass(t, ConflictError):
                         # ouch, a user saw this conflict error :-(
-                    unresolved_conflict_errors += 1
+                        self.unresolved_conflict_errors += 1
 
             try:
                 log = aq_acquire(published, '__error_log__', containment=1)
@@ -190,32 +203,45 @@ def zpublisher_exception_hook(published, REQUEST, t, v, traceback):
                 !='text/html'):
                 raise t, v, traceback
 
+            # Lookup a view for the exception and render it, then
+            # raise the rendered value as the exception value
+            # (basically the same that 'raise_standardErrorMessage'
+            # does. The view is named 'index.html' because that's what
+            # Zope 3 uses as well.
+            view = queryMultiAdapter((v, REQUEST), name=u'index.html')
+            if view is not None:
+                v = view()
+                response = REQUEST.RESPONSE
+                response.setStatus(t)
+                response.setBody(v)
+                return response
+
             if (published is None or published is app or
                 type(published) is ListType):
                 # At least get the top-level object
                 published=app.__bobo_traverse__(REQUEST).__of__(
                     RequestContainer(REQUEST))
 
-        published=getattr(published, 'im_self', published)
+            published = getattr(published, 'im_self', published)
             while 1:
-            f=getattr(published, 'raise_standardErrorMessage', None)
+                f = getattr(published, self.raise_error_message, None)
                 if f is None:
-                published=getattr(published, 'aq_parent', None)
+                    published = getattr(published, 'aq_parent', None)
                     if published is None:
                         raise t, v, traceback
                 else:
                     break
 
-        client=published
+            client = published
             while 1:
-            if getattr(client, 'standard_error_message', None) is not None:
+                if getattr(client, self.error_message, None) is not None:
                     break
-            client=getattr(client, 'aq_parent', None)
+                client = getattr(client, 'aq_parent', None)
                 if client is None:
                     raise t, v, traceback
 
             if REQUEST.get('AUTHENTICATED_USER', None) is None:
-            REQUEST['AUTHENTICATED_USER']=AccessControl.User.nobody
+                REQUEST['AUTHENTICATED_USER'] = AccessControl.User.nobody
 
             try:
                 f(client, REQUEST, t, v, traceback, error_log_url=error_log_url)
@@ -224,8 +250,9 @@ def zpublisher_exception_hook(published, REQUEST, t, v, traceback):
                 f(client, REQUEST, t, v, traceback)
 
         finally:
-        traceback=None
+            traceback = None
 
+zpublisher_exception_hook = ZPublisherExceptionHook()
 ac_logger = logging.getLogger('event.AccessControl')
 
 class TransactionsManager:

lib/python/Zope2/App/tests/__init__.py

+##############################################################################
+#
+# Copyright (c) 2007 Zope Corporation and Contributors.
+# All Rights Reserved.
+#
+# This software is subject to the provisions of the Zope Public License,
+# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
+# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
+# FOR A PARTICULAR PURPOSE.
+#
+##############################################################################
+
+"""Tests of the Zope2.App package."""

lib/python/zExceptions/__init__.py

@@ -20,17 +20,22 @@ $Id$
 
 from unauthorized import Unauthorized
 
+from zope.interface import implements
+from zope.interface.common.interfaces import IException
+from zope.publisher.interfaces import INotFound
+from zope.security.interfaces import IForbidden
+
 class BadRequest(Exception):
-    pass
+    implements(IException)
 
 class InternalError(Exception):
-    pass
+    implements(IException)
 
 class NotFound(Exception):
-    pass
+    implements(INotFound)
 
 class Forbidden(Exception):
-    pass
+    implements(IForbidden)
 
 class MethodNotAllowed(Exception):
     pass

lib/python/zExceptions/unauthorized.py

@@ -15,9 +15,13 @@ $Id$
 """
 
 from types import StringType
+from zope.interface import implements
+from zope.security.interfaces import IUnauthorized
 
 class Unauthorized(Exception):
-    """Some user wasn't allowed to access a resource"""
+    """Some user wasn't allowed to access a resource
+    """
+    implements(IUnauthorized)
 
     def __init__(self, message=None, value=None, needed=None, name=None, **kw):
         """Possible signatures: