Features

--------

- A ``request.matched_route`` attribute is now added to the request
  when a route has matched.  Its value is the "route" object that
  matched (see the ``IRoute`` interface within
  ``repoze.bfg.interfaces`` API documentation for the API of a route
  object).

- The ``exception`` attribute of the request is now set slightly
  earlier and in a slightly different set of scenarios, for benefit of
  "finished callbacks" and "response callbacks".  In previous
  versions, the ``exception`` attribute of the request was not set at
  all if an exception view was not found.  In this version, the
  ``request.exception`` attribute is set immediately when an exception
  is caught by the router, even if an exception view could not be
  found.

Backwards Incompatibilities
---------------------------

- The router no longer sets the value ``wsgiorg.routing_args`` into
  the environ when a route matches. The value used to be something
  like ``((), matchdict)``.  This functionality was only ever
  obliquely referred to in change logs; it was never documented as an
  API.

- The ``exception`` attribute of the request now defaults to ``None``.
  In prior versions, the ``request.exception`` attribute did not exist
  if an exception was not raised by user code during request
  processing; it only began existence once an exception view was
  found.

Deprecations
------------

- References to the WSGI environment values ``bfg.routes.matchdict``
  and ``bfg.routes.route`` were removed from documentation.  These
  will stick around internally for several more releases, but it is
  ``request.matchdict`` and ``request.matched_route`` are now the
  "official" way to obtain the matchdict and the route object which
  resulted in the match.

Documentation
-------------

- Added two sections to the "Hooks" chapter of the documentation:
  "Using Response Callbacks" and "Using Finished Callbacks".

- Added documentation of the ``request.exception`` attribute to the
  ``repoze.bfg.request.Request`` API documentation.

- Added glossary entries for "response callback" and "finished
  callback".

- The "Request Processing" narrative chapter has been updated to note
  finished and response callback steps.

4 files changed, 57 insertions, 23 deletions

diff --git a/repoze/bfg/request.py b/repoze/bfg/request.py
index 6e5417d9a..84a5660ef 100644
--- a/repoze/bfg/request.py
+++ b/repoze/bfg/request.py
@@ -40,6 +40,7 @@ class Request(WebobRequest):
     implements(IRequest)
     response_callbacks = ()
     finished_callbacks = ()
+    exception = None
     default_charset = 'utf-8'
 
     def add_response_callback(self, callback):
@@ -72,7 +73,13 @@ class Request(WebobRequest):
 
         Errors raised by callbacks are not handled specially.  They
         will be propagated to the caller of the :mod:`repoze.bfg`
-        router application.  """
+        router application.
+
+        .. note: ``add_response_callback`` is new in :mod:`repoze.bfg`
+           1.3.
+
+        See also: :ref:`using_response_callbacks`.
+        """
 
         callbacks = self.response_callbacks
         if not callbacks:
@@ -101,7 +108,7 @@ class Request(WebobRequest):
 
            def commit_callback(request):
                '''commit or abort the transaction associated with request'''
-               if hasattr(request, 'exception'):
+               if request.exception is not None:
                    transaction.abort()
                else:
                    transaction.commit()
@@ -126,7 +133,13 @@ class Request(WebobRequest):
 
         Errors raised by finished callbacks are not handled specially.
         They will be propagated to the caller of the :mod:`repoze.bfg`
-        router application.  """
+        router application.
+
+        .. note: ``add_finished_callback`` is new in :mod:`repoze.bfg`
+           1.3.
+
+        See also: :ref:`using_finished_callbacks`.
+        """
 
         callbacks = self.finished_callbacks
         if not callbacks:
diff --git a/repoze/bfg/router.py b/repoze/bfg/router.py
index 6532beec4..e6de4fdd7 100644
--- a/repoze/bfg/router.py
+++ b/repoze/bfg/router.py
@@ -57,9 +57,9 @@ class Router(object):
         has_listeners = registry.has_listeners
         logger = self.logger
         manager = self.threadlocal_manager
-        threadlocals = {'registry':registry, 'request':None}
-        manager.push(threadlocals)
         request = None
+        threadlocals = {'registry':registry, 'request':request}
+        manager.push(threadlocals)
 
         try:
             # create the request
@@ -72,16 +72,19 @@ class Router(object):
             request_iface = IRequest
 
             try:
-                # find the root
+                # find the root object
                 root_factory = self.root_factory
                 if self.routes_mapper is not None:
                     info = self.routes_mapper(request)
                     match, route = info['match'], info['route']
                     if route is not None:
-                        environ['wsgiorg.routing_args'] = ((), match)
-                        environ['bfg.routes.route'] = route
+                        # TODO: kill off bfg.routes.* environ keys
+                        # when traverser requires request arg, and
+                        # cant cope with environ anymore (likely 1.4+)
+                        environ['bfg.routes.route'] = route 
                         environ['bfg.routes.matchdict'] = match
                         attrs['matchdict'] = match
+                        attrs['matched_route'] = route
                         request_iface = registry.queryUtility(
                             IRouteRequest,
                             name=route.name,
@@ -91,7 +94,7 @@ class Router(object):
                 root = root_factory(request)
                 attrs['root'] = root
 
-                # find a view callable
+                # find a context
                 traverser = adapters.queryAdapter(root, ITraverser)
                 if traverser is None:
                     traverser = ModelGraphTraverser(root)
@@ -102,6 +105,8 @@ class Router(object):
                     tdict['virtual_root_path'])
                 attrs.update(tdict)
                 has_listeners and registry.notify(ContextFound(request))
+
+                # find a view callable
                 context_iface = providedBy(context)
                 view_callable = adapters.lookup(
                     (IViewClassifier, request_iface, context_iface),
@@ -121,27 +126,31 @@ class Router(object):
                         logger and logger.debug(msg)
                     else:
                         msg = request.path_info
+                    # repoze.bfg.message should die
                     environ['repoze.bfg.message'] = msg
                     raise NotFound(msg)
                 else:
                     response = view_callable(context, request)
 
-            # handle exceptions raised during root finding and view lookup
+            # handle exceptions raised during root finding and view execution
             except Exception, why:
+                attrs['exception'] = why
+
                 for_ = (IExceptionViewClassifier,
                         request_iface.combined,
                         providedBy(why))
                 view_callable = adapters.lookup(for_, IView, default=None)
+
                 if view_callable is None:
                     raise
 
-                try:
+                # r.b.message should be deprecated
+                try: 
                     msg = why[0]
-                except Exception:
+                except:
                     msg = ''
                 environ['repoze.bfg.message'] = msg
 
-                attrs['exception'] = why
                 response = view_callable(why, request)
 
             # process the response
@@ -164,6 +173,7 @@ class Router(object):
             return app_iter
 
         finally:
+            # post-response cleanup
             try:
                 if request is not None and request.finished_callbacks:
                     request._process_finished_callbacks()
diff --git a/repoze/bfg/tests/test_request.py b/repoze/bfg/tests/test_request.py
index d8a3c09fb..ae52f8420 100644
--- a/repoze/bfg/tests/test_request.py
+++ b/repoze/bfg/tests/test_request.py
@@ -23,6 +23,10 @@ class TestRequest(unittest.TestCase):
         r = self._makeOne({'PATH_INFO':'/'})
         self.assertEqual(r.charset, 'utf-8')
 
+    def test_exception_defaults_to_None(self):
+        r = self._makeOne({'PATH_INFO':'/'})
+        self.assertEqual(r.exception, None)
+
     def test_params_decoded_from_utf_8_by_default(self):
         environ = {
             'PATH_INFO':'/',
diff --git a/repoze/bfg/tests/test_router.py b/repoze/bfg/tests/test_router.py
index 199602a96..fade0679b 100644
--- a/repoze/bfg/tests/test_router.py
+++ b/repoze/bfg/tests/test_router.py
@@ -518,12 +518,11 @@ class TestRouter(unittest.TestCase):
         self.assertEqual(request.subpath, [])
         self.assertEqual(request.context, context)
         self.assertEqual(request.root, root)
-        routing_args = environ['wsgiorg.routing_args'][1]
-        self.assertEqual(routing_args['action'], 'action1')
-        self.assertEqual(routing_args['article'], 'article1')
-        self.assertEqual(environ['bfg.routes.matchdict'], routing_args)
+        matchdict = {'action':'action1', 'article':'article1'}
+        self.assertEqual(environ['bfg.routes.matchdict'], matchdict)
         self.assertEqual(environ['bfg.routes.route'].name, 'foo')
-        self.assertEqual(request.matchdict, routing_args)
+        self.assertEqual(request.matchdict, matchdict)
+        self.assertEqual(request.matched_route.name, 'foo')
 
     def test_call_route_matches_doesnt_overwrite_subscriber_iface(self):
         from repoze.bfg.interfaces import INewRequest
@@ -559,12 +558,11 @@ class TestRouter(unittest.TestCase):
         self.assertEqual(request.subpath, [])
         self.assertEqual(request.context, context)
         self.assertEqual(request.root, root)
-        routing_args = environ['wsgiorg.routing_args'][1]
-        self.assertEqual(routing_args['action'], 'action1')
-        self.assertEqual(routing_args['article'], 'article1')
-        self.assertEqual(environ['bfg.routes.matchdict'], routing_args)
+        matchdict = {'action':'action1', 'article':'article1'}
+        self.assertEqual(environ['bfg.routes.matchdict'], matchdict)
         self.assertEqual(environ['bfg.routes.route'].name, 'foo')
-        self.assertEqual(request.matchdict, routing_args)
+        self.assertEqual(request.matchdict, matchdict)
+        self.assertEqual(request.matched_route.name, 'foo')
         self.failUnless(IFoo.providedBy(request))
 
     def test_root_factory_raises_notfound(self):
@@ -634,6 +632,12 @@ class TestRouter(unittest.TestCase):
             pass
         from repoze.bfg.interfaces import IRequest
         from repoze.bfg.interfaces import IViewClassifier
+        from repoze.bfg.interfaces import IRequestFactory
+        def rfactory(environ):
+            return request
+        self.registry.registerUtility(rfactory, IRequestFactory)
+        from repoze.bfg.request import Request
+        request = Request.blank('/')
         context = DummyContext()
         directlyProvides(context, IContext)
         self._registerTraverserFactory(context, subpath=[''])
@@ -644,6 +648,9 @@ class TestRouter(unittest.TestCase):
         router = self._makeOne()
         start_response = DummyStartResponse()
         self.assertRaises(RuntimeError, router, environ, start_response)
+        # ``exception`` must be attached to request even if a suitable
+        # exception view cannot be found
+        self.assertEqual(request.exception.__class__, RuntimeError)
 
     def test_call_view_raises_exception_view(self):
         from repoze.bfg.interfaces import IViewClassifier