From ef5149051623da25d24002132828c658b6dcfee4 Mon Sep 17 00:00:00 2001
From: Chris McDonough <chrism@agendaless.com>
Date: Wed, 21 Oct 2009 16:02:24 +0000
Subject: Add Respond exception.

---
 repoze/bfg/exceptions.py        | 26 ++++++++++++++++++++++++++
 repoze/bfg/router.py            |  3 +++
 repoze/bfg/tests/test_router.py | 30 +++++++++++++++++++++++++++---
 3 files changed, 56 insertions(+), 3 deletions(-)

(limited to 'repoze')

diff --git a/repoze/bfg/exceptions.py b/repoze/bfg/exceptions.py
index afd617a2c..bc05fa699 100644
--- a/repoze/bfg/exceptions.py
+++ b/repoze/bfg/exceptions.py
@@ -22,3 +22,29 @@ class NotFound(Exception):
     into the WSGI environment under the ``repoze.bfg.message`` key,
     for availability to the Not Found view."""
 
+class Respond(Exception):
+    """\
+    Raise this exception during view execution to return a response
+    immediately without proceeeding any further through the codepath.
+    Use of this exception is effectively a 'goto': its target is the
+    exception handler within the :mod:`repoze.bfg' router that catches
+    the exception and returns a response immediately.  Note that
+    because this exception is caught by the router, it will not
+    propagate to any WSGI middleware.  Note that this exception is
+    typically only used by the framework itself and by authentication
+    plugins to the framework.
+
+    The exception must be initialized which a single argument, which
+    is a :term:`response` object.
+
+    An example:
+
+    .. code-block:: python
+       :linenos:
+
+       from webob.exc import HTTPFound
+       from repoze.bfg.exceptions import Respond
+       response = HTTPFound(location='http://example.com')
+       raise Respond(response)
+    """
+    
diff --git a/repoze/bfg/router.py b/repoze/bfg/router.py
index 1b894129b..c87065e14 100644
--- a/repoze/bfg/router.py
+++ b/repoze/bfg/router.py
@@ -19,6 +19,7 @@ from repoze.bfg.events import NewResponse
 from repoze.bfg.events import WSGIApplicationCreatedEvent
 from repoze.bfg.exceptions import Forbidden
 from repoze.bfg.exceptions import NotFound
+from repoze.bfg.exceptions import Respond
 from repoze.bfg.request import request_factory
 from repoze.bfg.threadlocal import manager
 from repoze.bfg.traversal import ModelGraphTraverser
@@ -115,6 +116,8 @@ class Router(object):
                     environ = getattr(request, 'environ', {})
                     environ['repoze.bfg.message'] = msg
                     response = self.notfound_view(context, request)
+                except Respond, why:
+                    response = why[0]
 
             registry.has_listeners and registry.notify(NewResponse(response))
 
diff --git a/repoze/bfg/tests/test_router.py b/repoze/bfg/tests/test_router.py
index 151734b9b..76b33d204 100644
--- a/repoze/bfg/tests/test_router.py
+++ b/repoze/bfg/tests/test_router.py
@@ -334,7 +334,7 @@ class TestRouter(unittest.TestCase):
         self.assertEqual(start_response.status, '404 Not Found')
         self.failUnless('404' in result[0])
 
-    def test_call_view_raises_unauthorized(self):
+    def test_call_view_raises_forbidden(self):
         from zope.interface import Interface
         from zope.interface import directlyProvides
         class IContext(Interface):
@@ -372,6 +372,25 @@ class TestRouter(unittest.TestCase):
         self.assertEqual(start_response.status, '404 Not Found')
         self.assertEqual(environ['repoze.bfg.message'], 'notfound')
 
+    def test_call_view_raises_respond(self):
+        from zope.interface import Interface
+        from zope.interface import directlyProvides
+        class IContext(Interface):
+            pass
+        from repoze.bfg.interfaces import IRequest
+        context = DummyContext()
+        directlyProvides(context, IContext)
+        self._registerTraverserFactory(context, subpath=[''])
+        response = DummyResponse('200 OK')
+        raised = DummyResponse('201 Created')
+        view = DummyView(response, raise_respond=raised)
+        environ = self._makeEnviron()
+        self._registerView(view, '', IContext, IRequest)
+        router = self._makeOne()
+        start_response = DummyStartResponse()
+        response = router(environ, start_response)
+        self.assertEqual(start_response.status, '201 Created')
+
     def test_call_eventsends(self):
         context = DummyContext()
         self._registerTraverserFactory(context)
@@ -466,10 +485,11 @@ class DummyContext:
 
 class DummyView:
     def __init__(self, response, raise_unauthorized=False,
-                 raise_notfound=False):
+                 raise_notfound=False, raise_respond=False):
         self.response = response
         self.raise_unauthorized = raise_unauthorized
         self.raise_notfound = raise_notfound
+        self.raise_respond = raise_respond
 
     def __call__(self, context, request):
         if self.raise_unauthorized:
@@ -478,6 +498,9 @@ class DummyView:
         if self.raise_notfound:
             from repoze.bfg.exceptions import NotFound
             raise NotFound('notfound')
+        if self.raise_respond:
+            from repoze.bfg.exceptions import Respond
+            raise Respond(self.raise_respond)
         return self.response
 
 class DummyRootFactory:
@@ -495,9 +518,10 @@ class DummyStartResponse:
         self.headers = headers
         
 class DummyResponse:
-    status = '200 OK'
     headerlist = ()
     app_iter = ()
+    def __init__(self, status='200 OK'):
+        self.status = status
     
 class DummyThreadLocalManager:
     def __init__(self):
-- 
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