- Add ``xhr``, ``accept``, and ``header`` view configuration

  predicates to ZCML view declaration, ZCML route declaration, and
  ``bfg_view`` decorator.  See the ``Views`` narrative documentation
  chapter for more information about these predicates.

6 files changed, 743 insertions, 131 deletions

diff --git a/CHANGES.txt b/CHANGES.txt
index d072cd79c..d045d261a 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,12 +1,23 @@
 Next release
 ============
 
+Features
+--------
+
+- Add ``xhr``, ``accept``, and ``header`` view configuration
+  predicates to ZCML view declaration, ZCML route declaration, and
+  ``bfg_view`` decorator.  See the ``Views`` narrative documentation
+  chapter for more information about these predicates.
+
 Documentation
 -------------
 
 - Virtual hosting narrative docs chapter updated with info about
   ``mod_wsgi``.
 
+- Point all index URLs at the literal 1.1 index (this alpha cycle may
+  go on a while).
+
 1.1a5 (2009-10-10)
 ==================
 
diff --git a/docs/narr/urldispatch.rst b/docs/narr/urldispatch.rst
index a43d5e125..7a2a184f7 100644
--- a/docs/narr/urldispatch.rst
+++ b/docs/narr/urldispatch.rst
@@ -215,6 +215,56 @@ view_renderer
 
   .. note:: This feature is new as of :mod:`repoze.bfg` 1.1.
 
+view_xhr
+
+  Thie value should be either ``True`` or ``False``.  If this value is
+  specified and is ``True``, the :term:`request` must possess an
+  ``HTTP_X_REQUESTED_WITH`` (aka ``X-Requested-With``) header for this
+  view to be found and called.  This is useful for detecting AJAX
+  requests issued from jQuery, Prototype and other Javascript
+  libraries.
+
+  This attribute can also be spelled as ``xhr``.
+
+  .. note:: This feature is new as of :mod:`repoze.bfg` 1.1.
+
+view_accept
+
+  The value of this attribute represents a match query for one or more
+  mimetypes in the ``Accept`` HTTP request header.  If this value is
+  specified, it must be in one of the following forms: a mimetype
+  match token in the form ``text/plain``, a wildcard mimetype match
+  token in the form ``text/*`` or a match-all wildcard mimetype match
+  token in the form ``*/*``.  If any of the forms matches the
+  ``Accept`` header of the request, this predicate will be true.
+
+  This attribute can also be spelled as ``accept``.
+
+  .. note:: This feature is new as of :mod:`repoze.bfg` 1.1.
+
+view_header
+
+  The value of this attribute represents an HTTP header name or a
+  header name/value pair.  If the value contains a ``:`` (colon), it
+  will be considered a name/value pair (e.g. ``User-Agent:Mozilla/.*``
+  or ``Host:localhost``).  The *value* of an attribute that represent
+  a name/value pair should be a regular expression.  If the value does
+  not contain a colon, the entire value will be considered to be the
+  header name (e.g. ``If-Modified-Since``).  If the value evaluates to
+  a header name only without a value, the header specified by the name
+  must be present in the request for this predicate to be true.  If
+  the value evaluates to a header name/value pair, the header
+  specified by the name must be present in the request *and* the
+  regular expression specified as the value must match the header
+  value.  Whether or not the value represents a header name or a
+  header name/value pair, the case of the header name is not
+  significant.
+
+  This attribute can also be spelled as ``header``.
+
+  .. note:: This feature is new as of :mod:`repoze.bfg` 1.1.
+
+
 The Matchdict
 -------------
 
diff --git a/docs/narr/views.rst b/docs/narr/views.rst
index c8c779380..3979ec8f6 100644
--- a/docs/narr/views.rst
+++ b/docs/narr/views.rst
@@ -472,6 +472,49 @@ request_type
   ``request_method`` attribute instead for maximum forward
   compatibility.
 
+xhr
+
+  Thie value should be either ``True`` or ``False``.  If this value is
+  specified and is ``True``, the :term:`request` must possess an
+  ``HTTP_X_REQUESTED_WITH`` (aka ``X-Requested-With``) header that has
+  the value ``XMLHttpRequest`` for this view to be found and called.
+  This is useful for detecting AJAX requests issued from jQuery,
+  Prototype and other Javascript libraries.
+
+  .. note:: This feature is new as of :mod:`repoze.bfg` 1.1.
+
+accept
+
+  The value of this attribute represents a match query for one or more
+  mimetypes in the ``Accept`` HTTP request header.  If this value is
+  specified, it must be in one of the following forms: a mimetype
+  match token in the form ``text/plain``, a wildcard mimetype match
+  token in the form ``text/*`` or a match-all wildcard mimetype match
+  token in the form ``*/*``.  If any of the forms matches the
+  ``Accept`` header of the request, this predicate will be true.
+
+  .. note:: This feature is new as of :mod:`repoze.bfg` 1.1.
+
+header
+
+  The value of this attribute represents an HTTP header name or a
+  header name/value pair.  If the value contains a ``:`` (colon), it
+  will be considered a name/value pair (e.g. ``User-Agent:Mozilla/.*``
+  or ``Host:localhost``).  The *value* of an attribute that represent
+  a name/value pair should be a regular expression.  If the value does
+  not contain a colon, the entire value will be considered to be the
+  header name (e.g. ``If-Modified-Since``).  If the value evaluates to
+  a header name only without a value, the header specified by the name
+  must be present in the request for this predicate to be true.  If
+  the value evaluates to a header name/value pair, the header
+  specified by the name must be present in the request *and* the
+  regular expression specified as the value must match the header
+  value.  Whether or not the value represents a header name or a
+  header name/value pair, the case of the header name is not
+  significant.
+
+  .. note:: This feature is new as of :mod:`repoze.bfg` 1.1.
+
 .. _mapping_views_to_urls_using_a_decorator_section:
 
 View Configuration Using the ``@bfg_view`` Decorator
@@ -484,10 +527,11 @@ functions with URLs instead of using :term:`ZCML` for the same
 purpose.  ``repoze.bfg.view.bfg_view`` can be used to associate
 ``for``, ``name``, ``permission`` and ``request_method``,
 ``containment``, ``request_param`` and ``request_type``, ``attr``,
-``renderer``, and ``wrapper`` information -- as done via the
-equivalent ZCML -- with a function that acts as a :mod:`repoze.bfg`
-view.  All ZCML attributes (save for the ``view`` attribute) are
-available in decorator form and mean precisely the same thing.
+``renderer``, ``wrapper``, ``xhr``, ``accept``, and ``header``
+information -- as done via the equivalent ZCML -- with a function that
+acts as a :mod:`repoze.bfg` view.  All ZCML attributes (save for the
+``view`` attribute) are available in decorator form and mean precisely
+the same thing.
 
 To make :mod:`repoze.bfg` process your ``@bfg_view`` declarations, you
 *must* insert the following boilerplate into your application's
@@ -582,6 +626,26 @@ If ``containment`` is supplied, the view will be invoked only if a
 location parent supplies the interface or class implied by the
 provided value.
 
+If ``xhr`` is specified, it must be a boolean value.  If the value is
+``True``, the view will only be invoked if the request's
+``X-Requested-With`` header has the value ``XMLHttpRequest``.
+
+If ``accept`` is specified, it must be a mimetype value.  If
+``accept`` is specified, the view will only be invoked if the
+``Accept`` HTTP header matches the value requested.  See the
+description of ``accept`` in :ref:`the_view_zcml_directive` for
+information about the allowable composition and matching behavior of
+this value.
+
+If ``header`` is specified, it must be a header name or a
+``headername:headervalue`` pair.  If ``header`` is specified, and
+possesses a value the view will only be invoked if an HTTP header
+matches the value requested.  If ``header`` is specified without a
+value (a bare header name only), the view will only be invoked if the
+HTTP header exists with any value in the request.  See the description
+of ``header`` in :ref:`the_view_zcml_directive` for information about
+the allowable composition and matching behavior of this value.
+
 View lookup ordering for views registered with the ``bfg_view``
 decorator is the same as for those registered via ZCML.  See
 :ref:`view_lookup_ordering` for more information.
diff --git a/repoze/bfg/tests/test_zcml.py b/repoze/bfg/tests/test_zcml.py
index 7cbadd1e2..1f0fc44d8 100644
--- a/repoze/bfg/tests/test_zcml.py
+++ b/repoze/bfg/tests/test_zcml.py
@@ -40,7 +40,7 @@ class TestViewDirective(unittest.TestCase):
 
         action = actions[0]
         discrim = ('view', IFoo, '', IRequest, IView, None, None, None, None,
-                   None)
+                   None, False, None, None)
         self.assertEqual(action['discriminator'], discrim)
         register = action['callable']
         register()
@@ -72,7 +72,7 @@ class TestViewDirective(unittest.TestCase):
 
         action = actions[0]
         discrim = ('view', IFoo, '', IRequest, IView, None, None, None, None,
-                   None)
+                   None, False, None, None)
         self.assertEqual(action['discriminator'], discrim)
         register = action['callable']
         register()
@@ -109,7 +109,7 @@ class TestViewDirective(unittest.TestCase):
 
         action = actions[0]
         discrim = ('view', IFoo, '', IRequest, IView, None, None, None, None,
-                   None)
+                   None, False, None, None)
         self.assertEqual(action['discriminator'], discrim)
         register = action['callable']
         register()
@@ -141,7 +141,7 @@ class TestViewDirective(unittest.TestCase):
 
         action = actions[0]
         discrim = ('view', IFoo, '', IRequest, IView, None, None, None, None,
-                   None)
+                   None, False, None, None)
         self.assertEqual(action['discriminator'], discrim)
         register = action['callable']
         register()
@@ -181,7 +181,7 @@ class TestViewDirective(unittest.TestCase):
 
         action = actions[0]
         discrim = ('view', IFoo, '', IRequest, IView, None, None, None, None,
-                   None)
+                   None, False, None, None)
         self.assertEqual(action['discriminator'], discrim)
         register = action['callable']
         register()
@@ -220,7 +220,7 @@ class TestViewDirective(unittest.TestCase):
 
         action = actions[0]
         discrim = ('view', IFoo, '', IRequest, IView, None, None, None, None,
-                   None)
+                   None, False, None, None)
         self.assertEqual(action['discriminator'], discrim)
         register = action['callable']
         register()
@@ -260,7 +260,7 @@ class TestViewDirective(unittest.TestCase):
 
         action = actions[0]
         discrim = ('view', IFoo, '', IRequest, IView, None, None, None, None,
-                   None)
+                   None, False, None, None)
         self.assertEqual(action['discriminator'], discrim)
         register = action['callable']
         register()
@@ -299,7 +299,7 @@ class TestViewDirective(unittest.TestCase):
 
         action = actions[0]
         discrim = ('view', IFoo, '', IRequest, IView, None, None, None, None,
-                   None)
+                   None, False, None, None)
         self.assertEqual(action['discriminator'], discrim)
         register = action['callable']
         register()
@@ -350,7 +350,7 @@ class TestViewDirective(unittest.TestCase):
 
         action = actions[0]
         discrim = ('view', IFoo, '', IRequest, IView, None, None, None, None,
-                   None)
+                   None, False, None, None)
         self.assertEqual(action['discriminator'], discrim)
         register = action['callable']
         register()
@@ -386,7 +386,7 @@ class TestViewDirective(unittest.TestCase):
 
         action = actions[0]
         discrim = ('view', IFoo, '', IRequest, IView, None, None, None, None,
-                   None)
+                   None, False, None, None)
         self.assertEqual(action['discriminator'], discrim)
         register = action['callable']
         register()
@@ -415,7 +415,7 @@ class TestViewDirective(unittest.TestCase):
 
         action = actions[0]
         discrim = ('view', IFoo, '', IDummy, IView, None, None, None, None,
-                   None)
+                   None, False, None, None)
         self.assertEqual(action['discriminator'], discrim)
         register = action['callable']
         register()
@@ -445,7 +445,8 @@ class TestViewDirective(unittest.TestCase):
         self.assertEqual(len(actions), 1)
 
         action = actions[0]
-        discrim = ('view', IFoo, '', Dummy, IView, None, None, None, None, None)
+        discrim = ('view', IFoo, '', Dummy, IView, None, None, None, None,
+                   None, False, None, None)
         self.assertEqual(action['discriminator'], discrim)
         register = action['callable']
         register()
@@ -472,7 +473,7 @@ class TestViewDirective(unittest.TestCase):
 
         action = actions[0]
         discrim = ('view', IFoo, '', IRequest, IView, None, None, 'GET', None,
-                   None)
+                   None, False, None, None)
         self.assertEqual(action['discriminator'], discrim)
         register = action['callable']
         register()
@@ -502,7 +503,7 @@ class TestViewDirective(unittest.TestCase):
         self.assertEqual(len(actions), 1)
 
         discrim = ('view', IFoo, '', IRequest, IView, None, None, None, None,
-                   None)
+                   None, False, None, None)
         self.assertEqual(actions[0]['discriminator'], discrim)
         register = actions[0]['callable']
         register()
@@ -536,7 +537,7 @@ class TestViewDirective(unittest.TestCase):
         factory = sm.getUtility(IRouteRequest, 'foo')
         request_type = implementedBy(factory)
         discrim = ('view', IFoo, '', request_type, IView, None, None, None,
-                   'foo', None)
+                   'foo', None, False, None, None)
         self.assertEqual(action['discriminator'], discrim)
         the_view = sm.adapters.lookup((IFoo, request_type), IView, name='')
         request = factory({})
@@ -559,7 +560,7 @@ class TestViewDirective(unittest.TestCase):
         self.assertEqual(len(actions), 1)
         action = actions[0]
         discrim = ('view', IFoo, '', IRequest, IView, None, None, 'POST', None,
-                   None)
+                   None, False, None, None)
         self.assertEqual(action['discriminator'], discrim)
         register = action['callable']
         register()
@@ -586,7 +587,7 @@ class TestViewDirective(unittest.TestCase):
         self.assertEqual(len(actions), 1)
         action = actions[0]
         discrim = ('view', IFoo, '', IRequest, IView, None, None, 'POST', None,
-                   None)
+                   None, False, None, None)
         self.assertEqual(action['discriminator'], discrim)
         register = action['callable']
         register()
@@ -612,7 +613,7 @@ class TestViewDirective(unittest.TestCase):
         self.assertEqual(len(actions), 1)
         action = actions[0]
         discrim = ('view', IFoo, '', IRequest, IView, None, 'abc', None, None,
-                   None)
+                   None, False, None, None)
         self.assertEqual(action['discriminator'], discrim)
         register = action['callable']
         register()
@@ -639,7 +640,7 @@ class TestViewDirective(unittest.TestCase):
         self.assertEqual(len(actions), 1)
         action = actions[0]
         discrim = ('view', IFoo, '', IRequest, IView, None, 'abc', None, None,
-                   None)
+                   None, False, None, None)
         self.assertEqual(action['discriminator'], discrim)
         register = action['callable']
         register()
@@ -665,7 +666,7 @@ class TestViewDirective(unittest.TestCase):
         self.assertEqual(len(actions), 1)
         action = actions[0]
         discrim = ('view', IFoo, '', IRequest, IView, None, 'abc', None, None,
-                   None)
+                   None, False, None, None)
         self.assertEqual(action['discriminator'], discrim)
         register = action['callable']
         register()
@@ -692,7 +693,7 @@ class TestViewDirective(unittest.TestCase):
         self.assertEqual(len(actions), 1)
         action = actions[0]
         discrim = ('view', IFoo, '', IRequest, IView, None, 'abc', None, None,
-                   None)
+                   None, False, None, None)
         self.assertEqual(action['discriminator'], discrim)
         register = action['callable']
         register()
@@ -701,6 +702,235 @@ class TestViewDirective(unittest.TestCase):
         request.params = {'abc':'456'}
         self.assertRaises(NotFound, wrapper, None, request)
 
+    def test_with_xhr_true(self):
+        from zope.component import getSiteManager
+        from zope.interface import Interface
+        from repoze.bfg.interfaces import IRequest
+        from repoze.bfg.interfaces import IView
+        class IFoo(Interface):
+            pass
+        context = DummyContext()
+        view = lambda *arg: None
+        sm = getSiteManager()
+        def view(context, request):
+            return '123'
+        self._callFUT(context, None, IFoo, view=view, xhr=True)
+        actions = context.actions
+        self.assertEqual(len(actions), 1)
+        action = actions[0]
+        discrim = ('view', IFoo, '', IRequest, IView, None, None, None, None,
+                   None, True, None, None)
+        self.assertEqual(action['discriminator'], discrim)
+        register = action['callable']
+        register()
+        wrapper = sm.adapters.lookup((IFoo, IRequest), IView, name='')
+        request = DummyRequest()
+        request.is_xhr = True
+        self.assertEqual(wrapper(None, request), '123')
+
+    def test_with_xhr_false(self):
+        from zope.component import getSiteManager
+        from zope.interface import Interface
+        from repoze.bfg.interfaces import IRequest
+        from repoze.bfg.interfaces import IView
+        from repoze.bfg.exceptions import NotFound
+        class IFoo(Interface):
+            pass
+        context = DummyContext()
+        view = lambda *arg: None
+        sm = getSiteManager()
+        def view(context, request):
+            return '123'
+        self._callFUT(context, None, IFoo, view=view, xhr=True)
+        actions = context.actions
+        self.assertEqual(len(actions), 1)
+        action = actions[0]
+        discrim = ('view', IFoo, '', IRequest, IView, None, None, None, None,
+                   None, True, None, None)
+        self.assertEqual(action['discriminator'], discrim)
+        register = action['callable']
+        register()
+        wrapper = sm.adapters.lookup((IFoo, IRequest), IView, name='')
+        request = DummyRequest()
+        request.is_xhr = False
+        self.assertRaises(NotFound, wrapper, None, request)
+
+    def test_with_header_badregex(self):
+        from zope.component import getSiteManager
+        from zope.interface import Interface
+        from repoze.bfg.interfaces import IRequest
+        from repoze.bfg.interfaces import IView
+        from zope.configuration.exceptions import ConfigurationError
+        class IFoo(Interface):
+            pass
+        context = DummyContext()
+        view = lambda *arg: None
+        sm = getSiteManager()
+        def view(context, request):
+            return '123'
+        self.assertRaises(ConfigurationError, self._callFUT,
+                          context, None, IFoo,
+                          view=view, header='Host:a\\')
+
+    def test_with_header_noval_match(self):
+        from zope.component import getSiteManager
+        from zope.interface import Interface
+        from repoze.bfg.interfaces import IRequest
+        from repoze.bfg.interfaces import IView
+        class IFoo(Interface):
+            pass
+        context = DummyContext()
+        view = lambda *arg: None
+        sm = getSiteManager()
+        def view(context, request):
+            return '123'
+        self._callFUT(context, None, IFoo, view=view, header='Host')
+        actions = context.actions
+        self.assertEqual(len(actions), 1)
+        action = actions[0]
+        discrim = ('view', IFoo, '', IRequest, IView, None, None, None, None,
+                   None, False, None, 'Host')
+        self.assertEqual(action['discriminator'], discrim)
+        register = action['callable']
+        register()
+        wrapper = sm.adapters.lookup((IFoo, IRequest), IView, name='')
+        request = DummyRequest()
+        request.headers  = {'Host':'whatever'}
+        self.assertEqual(wrapper(None, request), '123')
+
+    def test_with_header_noval_nomatch(self):
+        from zope.component import getSiteManager
+        from zope.interface import Interface
+        from repoze.bfg.interfaces import IRequest
+        from repoze.bfg.interfaces import IView
+        from repoze.bfg.exceptions import NotFound
+        class IFoo(Interface):
+            pass
+        context = DummyContext()
+        view = lambda *arg: None
+        sm = getSiteManager()
+        def view(context, request):
+            return '123'
+        self._callFUT(context, None, IFoo, view=view, header='Host')
+        actions = context.actions
+        self.assertEqual(len(actions), 1)
+        action = actions[0]
+        discrim = ('view', IFoo, '', IRequest, IView, None, None, None, None,
+                   None, False, None, 'Host')
+        self.assertEqual(action['discriminator'], discrim)
+        register = action['callable']
+        register()
+        wrapper = sm.adapters.lookup((IFoo, IRequest), IView, name='')
+        request = DummyRequest()
+        request.headers  = {'NotHost':'whatever'}
+        self.assertRaises(NotFound, wrapper, None, request)
+
+    def test_with_header_val_match(self):
+        from zope.component import getSiteManager
+        from zope.interface import Interface
+        from repoze.bfg.interfaces import IRequest
+        from repoze.bfg.interfaces import IView
+        class IFoo(Interface):
+            pass
+        context = DummyContext()
+        view = lambda *arg: None
+        sm = getSiteManager()
+        def view(context, request):
+            return '123'
+        self._callFUT(context, None, IFoo, view=view, header=r'Host:\d')
+        actions = context.actions
+        self.assertEqual(len(actions), 1)
+        action = actions[0]
+        discrim = ('view', IFoo, '', IRequest, IView, None, None, None, None,
+                   None, False, None, r'Host:\d')
+        self.assertEqual(action['discriminator'], discrim)
+        register = action['callable']
+        register()
+        wrapper = sm.adapters.lookup((IFoo, IRequest), IView, name='')
+        request = DummyRequest()
+        request.headers  = {'Host':'1'}
+        self.assertEqual(wrapper(None, request), '123')
+
+    def test_with_header_val_nomatch(self):
+        from zope.component import getSiteManager
+        from zope.interface import Interface
+        from repoze.bfg.interfaces import IRequest
+        from repoze.bfg.interfaces import IView
+        from repoze.bfg.exceptions import NotFound
+        class IFoo(Interface):
+            pass
+        context = DummyContext()
+        view = lambda *arg: None
+        sm = getSiteManager()
+        def view(context, request):
+            return '123'
+        self._callFUT(context, None, IFoo, view=view, header=r'Host:\d')
+        actions = context.actions
+        self.assertEqual(len(actions), 1)
+        action = actions[0]
+        discrim = ('view', IFoo, '', IRequest, IView, None, None, None, None,
+                   None, False, None, r'Host:\d')
+        self.assertEqual(action['discriminator'], discrim)
+        register = action['callable']
+        register()
+        wrapper = sm.adapters.lookup((IFoo, IRequest), IView, name='')
+        request = DummyRequest()
+        request.headers  = {'Host':'abc'}
+        self.assertRaises(NotFound, wrapper, None, request)
+
+    def test_with_accept_match(self):
+        from zope.component import getSiteManager
+        from zope.interface import Interface
+        from repoze.bfg.interfaces import IRequest
+        from repoze.bfg.interfaces import IView
+        class IFoo(Interface):
+            pass
+        context = DummyContext()
+        view = lambda *arg: None
+        sm = getSiteManager()
+        def view(context, request):
+            return '123'
+        self._callFUT(context, None, IFoo, view=view, accept='text/xml')
+        actions = context.actions
+        self.assertEqual(len(actions), 1)
+        action = actions[0]
+        discrim = ('view', IFoo, '', IRequest, IView, None, None, None, None,
+                   None, False, 'text/xml', None)
+        self.assertEqual(action['discriminator'], discrim)
+        register = action['callable']
+        register()
+        wrapper = sm.adapters.lookup((IFoo, IRequest), IView, name='')
+        request = DummyRequest()
+        request.accept = ['text/xml']
+        self.assertEqual(wrapper(None, request), '123')
+
+    def test_with_accept_nomatch(self):
+        from zope.component import getSiteManager
+        from zope.interface import Interface
+        from repoze.bfg.interfaces import IRequest
+        from repoze.bfg.interfaces import IView
+        from repoze.bfg.exceptions import NotFound
+        class IFoo(Interface):
+            pass
+        context = DummyContext()
+        view = lambda *arg: None
+        sm = getSiteManager()
+        def view(context, request):
+            return '123'
+        self._callFUT(context, None, IFoo, view=view, accept='text/xml')
+        actions = context.actions
+        self.assertEqual(len(actions), 1)
+        action = actions[0]
+        discrim = ('view', IFoo, '', IRequest, IView, None, None, None, None,
+                   None, False, 'text/xml', None)
+        self.assertEqual(action['discriminator'], discrim)
+        register = action['callable']
+        register()
+        wrapper = sm.adapters.lookup((IFoo, IRequest), IView, name='')
+        request = DummyRequest()
+        request.accept = ['text/html']
+        self.assertRaises(NotFound, wrapper, None, request)
+
     def test_with_containment_true(self):
         from zope.component import getSiteManager
         from zope.interface import directlyProvides
@@ -720,7 +950,7 @@ class TestViewDirective(unittest.TestCase):
         self.assertEqual(len(actions), 1)
         action = actions[0]
         discrim = ('view', IFoo, '', IRequest, IView, IFoo, None, None, None,
-                   None)
+                   None, False, None, None)
         self.assertEqual(action['discriminator'], discrim)
         register = action['callable']
         register()
@@ -748,7 +978,7 @@ class TestViewDirective(unittest.TestCase):
         self.assertEqual(len(actions), 1)
         action = actions[0]
         discrim = ('view', IFoo, '', IRequest, IView, IFoo, None, None, None,
-                   None)
+                   None, False, None, None)
         self.assertEqual(action['discriminator'], discrim)
         register = action['callable']
         register()
@@ -776,7 +1006,7 @@ class TestViewDirective(unittest.TestCase):
         self.assertEqual(len(actions), 1)
         action = actions[0]
         discrim = ('view', IFoo, '', IRequest, IView, None, None, None, None,
-                   None)
+                   None, False, None, None)
         self.assertEqual(action['discriminator'], discrim)
         register = action['callable']
         register()
@@ -911,7 +1141,7 @@ class TestViewDirective(unittest.TestCase):
         self.assertEqual(len(actions), 1)
         action = actions[0]
         discrim = ('view', IFoo, '', IRequest, IView, None, None, None, None,
-                   None)
+                   None, False, None, None)
         self.assertEqual(action['discriminator'], discrim)
         register = action['callable']
         register()
@@ -938,7 +1168,7 @@ class TestViewDirective(unittest.TestCase):
         self.assertEqual(len(actions), 1)
         action = actions[0]
         discrim = ('view', Foo, '', IRequest, IView, None, None, None, None,
-                   None)
+                   None, False, None, None)
         self.assertEqual(action['discriminator'], discrim)
         register = action['callable']
         register()
@@ -1318,17 +1548,9 @@ class TestRouteDirective(unittest.TestCase):
         request_factory = sm.getUtility(IRouteRequest, 'name')
         request_type = implementedBy(request_factory)
         view_discriminator = view_action['discriminator']
-        self.assertEqual(len(view_discriminator), 10)
-        self.assertEqual(view_discriminator[0], 'view')
-        self.assertEqual(view_discriminator[1], None)
-        self.assertEqual(view_discriminator[2],'')
-        self.assertEqual(view_discriminator[3], request_type)
-        self.assertEqual(view_discriminator[4], IView)
-        self.assertEqual(view_discriminator[5], None)
-        self.assertEqual(view_discriminator[6], None)
-        self.assertEqual(view_discriminator[7], None)
-        self.assertEqual(view_discriminator[8], 'name')
-        self.assertEqual(view_discriminator[9], None)
+        discrim = ('view', None, '', request_type, IView, None, None, None,
+                   'name', None, False, None, None)
+        self.assertEqual(view_discriminator, discrim)
         register = view_action['callable']
         register()
         sm = getSiteManager()
@@ -1367,17 +1589,9 @@ class TestRouteDirective(unittest.TestCase):
         request_factory = sm.getUtility(IRouteRequest, 'name')
         request_type = implementedBy(request_factory)
         view_discriminator = view_action['discriminator']
-        self.assertEqual(len(view_discriminator), 10)
-        self.assertEqual(view_discriminator[0], 'view')
-        self.assertEqual(view_discriminator[1], IDummy)
-        self.assertEqual(view_discriminator[2],'')
-        self.assertEqual(view_discriminator[3], request_type)
-        self.assertEqual(view_discriminator[4], IView) 
-        self.assertEqual(view_discriminator[5], None)
-        self.assertEqual(view_discriminator[6], None)
-        self.assertEqual(view_discriminator[7], None)
-        self.assertEqual(view_discriminator[8], 'name')
-        self.assertEqual(view_discriminator[9], None)
+        discrim = ('view', IDummy, '', request_type, IView, None, None, None,
+                   'name', None, False, None, None)
+        self.assertEqual(view_discriminator, discrim)
         wrapped = sm.adapters.lookup((IDummy, request_type), IView, name='')
         request = DummyRequest()
         self.assertEqual(wrapped(None, request), '123')
@@ -1431,17 +1645,9 @@ class TestRouteDirective(unittest.TestCase):
         request_factory = sm.getUtility(IRouteRequest, 'name')
         request_type = implementedBy(request_factory)
         view_discriminator = view_action['discriminator']
-        self.assertEqual(len(view_discriminator), 10)
-        self.assertEqual(view_discriminator[0], 'view')
-        self.assertEqual(view_discriminator[1], None)
-        self.assertEqual(view_discriminator[2],'')
-        self.assertEqual(view_discriminator[3], request_type)
-        self.assertEqual(view_discriminator[4], IView) 
-        self.assertEqual(view_discriminator[5], None)
-        self.assertEqual(view_discriminator[6], None)
-        self.assertEqual(view_discriminator[7], 'GET')
-        self.assertEqual(view_discriminator[8], 'name')
-        self.assertEqual(view_discriminator[9], None)
+        discrim = ('view', None, '', request_type, IView, None, None, 'GET',
+                   'name', None, False, None, None)
+        self.assertEqual(view_discriminator, discrim)
         wrapped = sm.adapters.lookup((IDummy, request_type), IView, name='')
         self.failUnless(wrapped)
 
@@ -1476,17 +1682,9 @@ class TestRouteDirective(unittest.TestCase):
         request_factory = sm.getUtility(IRouteRequest, 'name')
         request_type = implementedBy(request_factory)
         view_discriminator = view_action['discriminator']
-        self.assertEqual(len(view_discriminator), 10)
-        self.assertEqual(view_discriminator[0], 'view')
-        self.assertEqual(view_discriminator[1], None)
-        self.assertEqual(view_discriminator[2],'')
-        self.assertEqual(view_discriminator[3], request_type)
-        self.assertEqual(view_discriminator[4], IView) 
-        self.assertEqual(view_discriminator[5], None)
-        self.assertEqual(view_discriminator[6], None)
-        self.assertEqual(view_discriminator[7], 'GET')
-        self.assertEqual(view_discriminator[8], 'name')
-        self.assertEqual(view_discriminator[9], None)
+        discrim = ('view', None, '', request_type, IView, None, None, 'GET',
+                   'name', None, False, None, None)
+        self.assertEqual(view_discriminator, discrim)
         wrapped = sm.adapters.lookup((IDummy, request_type), IView, name='')
         self.failUnless(wrapped)
 
@@ -1522,17 +1720,9 @@ class TestRouteDirective(unittest.TestCase):
         request_factory = sm.getUtility(IRouteRequest, 'name')
         request_type = implementedBy(request_factory)
         view_discriminator = view_action['discriminator']
-        self.assertEqual(len(view_discriminator), 10)
-        self.assertEqual(view_discriminator[0], 'view')
-        self.assertEqual(view_discriminator[1], None)
-        self.assertEqual(view_discriminator[2],'')
-        self.assertEqual(view_discriminator[3], request_type)
-        self.assertEqual(view_discriminator[4], IView) 
-        self.assertEqual(view_discriminator[5], None)
-        self.assertEqual(view_discriminator[6], None)
-        self.assertEqual(view_discriminator[7], 'GET')
-        self.assertEqual(view_discriminator[8], 'name')
-        self.assertEqual(view_discriminator[9], None)
+        discrim = ('view', None, '', request_type, IView, None, None, 'GET',
+                   'name', None, False, None, None)
+        self.assertEqual(view_discriminator, discrim)
         wrapped = sm.adapters.lookup((IDummy, request_type), IView, name='')
         self.failUnless(wrapped)
 
@@ -1567,17 +1757,9 @@ class TestRouteDirective(unittest.TestCase):
         request_factory = sm.getUtility(IRouteRequest, 'name')
         request_type = implementedBy(request_factory)
         view_discriminator = view_action['discriminator']
-        self.assertEqual(len(view_discriminator), 10)
-        self.assertEqual(view_discriminator[0], 'view')
-        self.assertEqual(view_discriminator[1], None)
-        self.assertEqual(view_discriminator[2],'')
-        self.assertEqual(view_discriminator[3], request_type)
-        self.assertEqual(view_discriminator[4], IView) 
-        self.assertEqual(view_discriminator[5], None)
-        self.assertEqual(view_discriminator[6], None)
-        self.assertEqual(view_discriminator[7], 'GET')
-        self.assertEqual(view_discriminator[8], 'name')
-        self.assertEqual(view_discriminator[9], None)
+        discrim = ('view', None, '', request_type, IView, None, None, 'GET',
+                   'name', None, False, None, None)
+        self.assertEqual(view_discriminator, discrim)
         wrapped = sm.adapters.lookup((IDummy, request_type), IView, name='')
         self.failUnless(wrapped)
 
@@ -1612,17 +1794,9 @@ class TestRouteDirective(unittest.TestCase):
         request_factory = sm.getUtility(IRouteRequest, 'name')
         request_type = implementedBy(request_factory)
         view_discriminator = view_action['discriminator']
-        self.assertEqual(len(view_discriminator), 10)
-        self.assertEqual(view_discriminator[0], 'view')
-        self.assertEqual(view_discriminator[1], None)
-        self.assertEqual(view_discriminator[2],'')
-        self.assertEqual(view_discriminator[3], request_type)
-        self.assertEqual(view_discriminator[4], IView) 
-        self.assertEqual(view_discriminator[5], True)
-        self.assertEqual(view_discriminator[6], None)
-        self.assertEqual(view_discriminator[7], None)
-        self.assertEqual(view_discriminator[8], 'name')
-        self.assertEqual(view_discriminator[9], None)
+        discrim = ('view', None, '', request_type, IView, True, None, None,
+                   'name', None, False, None, None)
+        self.assertEqual(view_discriminator, discrim)
         wrapped = sm.adapters.lookup((IDummy, request_type), IView, name='')
         self.failUnless(wrapped)
 
@@ -1657,17 +1831,232 @@ class TestRouteDirective(unittest.TestCase):
         request_factory = sm.getUtility(IRouteRequest, 'name')
         request_type = implementedBy(request_factory)
         view_discriminator = view_action['discriminator']
-        self.assertEqual(len(view_discriminator), 10)
-        self.assertEqual(view_discriminator[0], 'view')
-        self.assertEqual(view_discriminator[1], None)
-        self.assertEqual(view_discriminator[2],'')
-        self.assertEqual(view_discriminator[3], request_type)
-        self.assertEqual(view_discriminator[4], IView) 
-        self.assertEqual(view_discriminator[5], True)
-        self.assertEqual(view_discriminator[6], None)
-        self.assertEqual(view_discriminator[7], None)
-        self.assertEqual(view_discriminator[8], 'name')
-        self.assertEqual(view_discriminator[9], None)
+        discrim = ('view', None, '', request_type, IView, True, None, None,
+                   'name', None, False, None, None)
+        self.assertEqual(view_discriminator, discrim)
+        wrapped = sm.adapters.lookup((IDummy, request_type), IView, name='')
+        self.failUnless(wrapped)
+
+        route_action = actions[1]
+        route_callable = route_action['callable']
+        route_discriminator = route_action['discriminator']
+        route_args = route_action['args']
+        self.assertEqual(route_callable, connect_route)
+        self.assertEqual(len(route_discriminator), 2)
+        self.assertEqual(route_discriminator[0], 'route')
+        self.assertEqual(route_discriminator[1], 'name')
+        self.assertEqual(route_args, ('path', 'name', None))
+
+    def test_with_view_header(self):
+        from zope.component import getSiteManager
+        from zope.interface import implementedBy
+        from repoze.bfg.zcml import connect_route
+        from repoze.bfg.interfaces import IView
+        from repoze.bfg.interfaces import IRouteRequest
+        
+        context = DummyContext()
+        def view(context, request):
+            """ """
+        self._callFUT(context, 'name', 'path', view=view, view_header='Host')
+        actions = context.actions
+        self.assertEqual(len(actions), 2)
+
+        view_action = actions[0]
+        register = view_action['callable']
+        register()
+        sm = getSiteManager()
+        request_factory = sm.getUtility(IRouteRequest, 'name')
+        request_type = implementedBy(request_factory)
+        view_discriminator = view_action['discriminator']
+        discrim = ('view', None, '', request_type, IView, None, None, None,
+                   'name', None, False, None, 'Host')
+        self.assertEqual(view_discriminator, discrim)
+        wrapped = sm.adapters.lookup((IDummy, request_type), IView, name='')
+        self.failUnless(wrapped)
+
+        route_action = actions[1]
+        route_callable = route_action['callable']
+        route_discriminator = route_action['discriminator']
+        route_args = route_action['args']
+        self.assertEqual(route_callable, connect_route)
+        self.assertEqual(len(route_discriminator), 2)
+        self.assertEqual(route_discriminator[0], 'route')
+        self.assertEqual(route_discriminator[1], 'name')
+        self.assertEqual(route_args, ('path', 'name', None))
+
+    def test_with_view_header_alias(self):
+        from zope.component import getSiteManager
+        from zope.interface import implementedBy
+        from repoze.bfg.zcml import connect_route
+        from repoze.bfg.interfaces import IView
+        from repoze.bfg.interfaces import IRouteRequest
+        
+        context = DummyContext()
+        def view(context, request):
+            """ """
+        self._callFUT(context, 'name', 'path', view=view, header='Host')
+        actions = context.actions
+        self.assertEqual(len(actions), 2)
+
+        view_action = actions[0]
+        register = view_action['callable']
+        register()
+        sm = getSiteManager()
+        request_factory = sm.getUtility(IRouteRequest, 'name')
+        request_type = implementedBy(request_factory)
+        view_discriminator = view_action['discriminator']
+        discrim = ('view', None, '', request_type, IView, None, None, None,
+                   'name', None, False, None, 'Host')
+        self.assertEqual(view_discriminator, discrim)
+        wrapped = sm.adapters.lookup((IDummy, request_type), IView, name='')
+        self.failUnless(wrapped)
+
+        route_action = actions[1]
+        route_callable = route_action['callable']
+        route_discriminator = route_action['discriminator']
+        route_args = route_action['args']
+        self.assertEqual(route_callable, connect_route)
+        self.assertEqual(len(route_discriminator), 2)
+        self.assertEqual(route_discriminator[0], 'route')
+        self.assertEqual(route_discriminator[1], 'name')
+        self.assertEqual(route_args, ('path', 'name', None))
+
+    def test_with_view_xhr(self):
+        from zope.component import getSiteManager
+        from zope.interface import implementedBy
+        from repoze.bfg.zcml import connect_route
+        from repoze.bfg.interfaces import IView
+        from repoze.bfg.interfaces import IRouteRequest
+        
+        context = DummyContext()
+        def view(context, request):
+            """ """
+        self._callFUT(context, 'name', 'path', view=view, view_xhr=True)
+        actions = context.actions
+        self.assertEqual(len(actions), 2)
+
+        view_action = actions[0]
+        register = view_action['callable']
+        register()
+        sm = getSiteManager()
+        request_factory = sm.getUtility(IRouteRequest, 'name')
+        request_type = implementedBy(request_factory)
+        view_discriminator = view_action['discriminator']
+        discrim = ('view', None, '', request_type, IView, None, None, None,
+                   'name', None, True, None, None)
+        self.assertEqual(view_discriminator, discrim)
+        wrapped = sm.adapters.lookup((IDummy, request_type), IView, name='')
+        self.failUnless(wrapped)
+
+        route_action = actions[1]
+        route_callable = route_action['callable']
+        route_discriminator = route_action['discriminator']
+        route_args = route_action['args']
+        self.assertEqual(route_callable, connect_route)
+        self.assertEqual(len(route_discriminator), 2)
+        self.assertEqual(route_discriminator[0], 'route')
+        self.assertEqual(route_discriminator[1], 'name')
+        self.assertEqual(route_args, ('path', 'name', None))
+
+    def test_with_view_xhr_alias(self):
+        from zope.component import getSiteManager
+        from zope.interface import implementedBy
+        from repoze.bfg.zcml import connect_route
+        from repoze.bfg.interfaces import IView
+        from repoze.bfg.interfaces import IRouteRequest
+        
+        context = DummyContext()
+        def view(context, request):
+            """ """
+        self._callFUT(context, 'name', 'path', view=view, xhr=True)
+        actions = context.actions
+        self.assertEqual(len(actions), 2)
+
+        view_action = actions[0]
+        register = view_action['callable']
+        register()
+        sm = getSiteManager()
+        request_factory = sm.getUtility(IRouteRequest, 'name')
+        request_type = implementedBy(request_factory)
+        view_discriminator = view_action['discriminator']
+        discrim = ('view', None, '', request_type, IView, None, None, None,
+                   'name', None, True, None, None)
+        self.assertEqual(view_discriminator, discrim)
+        wrapped = sm.adapters.lookup((IDummy, request_type), IView, name='')
+        self.failUnless(wrapped)
+
+        route_action = actions[1]
+        route_callable = route_action['callable']
+        route_discriminator = route_action['discriminator']
+        route_args = route_action['args']
+        self.assertEqual(route_callable, connect_route)
+        self.assertEqual(len(route_discriminator), 2)
+        self.assertEqual(route_discriminator[0], 'route')
+        self.assertEqual(route_discriminator[1], 'name')
+        self.assertEqual(route_args, ('path', 'name', None))
+
+    def test_with_view_accept(self):
+        from zope.component import getSiteManager
+        from zope.interface import implementedBy
+        from repoze.bfg.zcml import connect_route
+        from repoze.bfg.interfaces import IView
+        from repoze.bfg.interfaces import IRouteRequest
+        
+        context = DummyContext()
+        def view(context, request):
+            """ """
+        self._callFUT(context, 'name', 'path', view=view,
+                      view_accept='text/xml')
+        actions = context.actions
+        self.assertEqual(len(actions), 2)
+
+        view_action = actions[0]
+        register = view_action['callable']
+        register()
+        sm = getSiteManager()
+        request_factory = sm.getUtility(IRouteRequest, 'name')
+        request_type = implementedBy(request_factory)
+        view_discriminator = view_action['discriminator']
+        discrim = ('view', None, '', request_type, IView, None, None, None,
+                   'name', None, False, 'text/xml', None)
+        self.assertEqual(view_discriminator, discrim)
+        wrapped = sm.adapters.lookup((IDummy, request_type), IView, name='')
+        self.failUnless(wrapped)
+
+        route_action = actions[1]
+        route_callable = route_action['callable']
+        route_discriminator = route_action['discriminator']
+        route_args = route_action['args']
+        self.assertEqual(route_callable, connect_route)
+        self.assertEqual(len(route_discriminator), 2)
+        self.assertEqual(route_discriminator[0], 'route')
+        self.assertEqual(route_discriminator[1], 'name')
+        self.assertEqual(route_args, ('path', 'name', None))
+
+    def test_with_view_xhr_alias(self):
+        from zope.component import getSiteManager
+        from zope.interface import implementedBy
+        from repoze.bfg.zcml import connect_route
+        from repoze.bfg.interfaces import IView
+        from repoze.bfg.interfaces import IRouteRequest
+        
+        context = DummyContext()
+        def view(context, request):
+            """ """
+        self._callFUT(context, 'name', 'path', view=view, accept='text/xml')
+        actions = context.actions
+        self.assertEqual(len(actions), 2)
+
+        view_action = actions[0]
+        register = view_action['callable']
+        register()
+        sm = getSiteManager()
+        request_factory = sm.getUtility(IRouteRequest, 'name')
+        request_type = implementedBy(request_factory)
+        view_discriminator = view_action['discriminator']
+        discrim = ('view', None, '', request_type, IView, None, None, None,
+                   'name', None, False, 'text/xml', None)
+        self.assertEqual(view_discriminator, discrim)
         wrapped = sm.adapters.lookup((IDummy, request_type), IView, name='')
         self.failUnless(wrapped)
 
@@ -2001,7 +2390,8 @@ class TestBFGViewGrokker(unittest.TestCase):
                         request_type=IRequest, route_name=None,
                         request_method=None, request_param=None,
                         containment=None, attr=None, renderer=None,
-                        wrapper_viewname=None)
+                        wrapper_viewname=None, xhr=False, header=None,
+                        accept=None)
         obj.__bfg_view_settings__ = settings
         context = DummyContext()
         result = grokker.grok('name', obj, context=context)
diff --git a/repoze/bfg/view.py b/repoze/bfg/view.py
index dba0f99b9..d6c47ec0f 100644
--- a/repoze/bfg/view.py
+++ b/repoze/bfg/view.py
@@ -240,7 +240,8 @@ class bfg_view(object):
 
     The following arguments are supported: ``for_``, ``permission``,
     ``name``, ``request_type``, ``route_name``, ``request_method``,
-    ``request_param``, and ``containment``.
+    ``request_param``, ``containment``, ``xhr``, ``accept``, and
+    ``header``.
 
     If ``for_`` is not supplied, the interface
     ``zope.interface.Interface`` (matching any context) is used.
@@ -295,6 +296,27 @@ class bfg_view(object):
     denoting that the view 'matches' the current request only if any graph
     lineage node possesses this class or interface.
 
+    If ``xhr`` is specified, it must be a boolean value.  If the value
+    is ``True``, the view will only be invoked if the request's
+    ``X-Requested-With`` header has the value ``XMLHttpRequest``.
+
+    If ``accept`` is specified, it must be a mimetype value.  If
+    ``accept`` is specified, the view will only be invoked if the
+    ``Accept`` HTTP header matches the value requested.  See the
+    description of ``accept`` in :ref:`the_view_zcml_directive` for
+    information about the allowable composition and matching behavior
+    of this value.
+
+    If ``header`` is specified, it must be a header name or a
+    ``headername:headervalue`` pair.  If ``header`` is specified, and
+    possesses a value the view will only be invoked if an HTTP header
+    matches the value requested.  If ``header`` is specified without a
+    value (a bare header name only), the view will only be invoked if
+    the HTTP header exists with any value in the request.  See the
+    description of ``header`` in :ref:`the_view_zcml_directive` for
+    information about the allowable composition and matching behavior
+    of this value.
+
     Any individual or all parameters can be omitted.  The simplest
     bfg_view declaration then becomes::
 
@@ -354,7 +376,8 @@ class bfg_view(object):
     """
     def __init__(self, name='', request_type=None, for_=None, permission=None,
                  route_name=None, request_method=None, request_param=None,
-                 containment=None, attr=None, renderer=None, wrapper=None):
+                 containment=None, attr=None, renderer=None, wrapper=None,
+                 xhr=False, accept=None, header=None):
         self.name = name
         self.request_type = request_type
         self.for_ = for_
@@ -366,6 +389,9 @@ class bfg_view(object):
         self.attr = attr
         self.renderer = renderer
         self.wrapper_viewname = wrapper
+        self.xhr = xhr
+        self.accept = accept
+        self.header = header
 
     def __call__(self, wrapped):
         wrapped.__bfg_view_settings__ = self.__dict__.copy()
diff --git a/repoze/bfg/zcml.py b/repoze/bfg/zcml.py
index adb1f1f31..b0f5a2595 100644
--- a/repoze/bfg/zcml.py
+++ b/repoze/bfg/zcml.py
@@ -1,3 +1,4 @@
+import re
 import sys
 
 from zope.configuration import xmlconfig
@@ -121,6 +122,26 @@ class IViewDirective(Interface):
                        'parameter exists which matches this string.'),
         required=False)
 
+    xhr = Bool(
+        title = (u'True if request has an X-Requested-With header with the '
+                 'value "XMLHttpRequest"'),
+        description=(u'Useful for detecting AJAX requests issued from '
+                     'jQuery, Protoype and other JavaScript libraries'),
+        required=False)
+
+    accept = TextLine(
+        title = (u'Mimetype(s) that must be present in "Accept" HTTP header '
+                 'for the view to match a request'),
+        description=(u'Accepts a mimetype match token in the form '
+                     '"text/plain", a wildcard mimetype match token in the '
+                     'form "text/*" or a match-all wildcard mimetype match '
+                     'token in the form "*/*".'),
+        required = False)
+
+    header = TextLine(
+        title=u'Header name/value pair in the form "name=<regex>"',
+        description=u'Regular expression matching for header values',
+        required = False)
 
 def view(
     _context,
@@ -136,6 +157,9 @@ def view(
     attr=None,
     renderer=None,
     wrapper=None,
+    xhr=False,
+    accept=None,
+    header=None,
     cacheable=True, # not used, here for b/w compat < 0.8
     ):
 
@@ -167,9 +191,6 @@ def view(
     if isinstance(request_type, basestring):
         request_type = _context.resolve(request_type)
 
-    predicates = []
-    weight = sys.maxint
-
     # Predicates are added to the predicate list in (presumed)
     # computation expense order.  All predicates associated with a
     # view must evaluate true for the view to "match" a request.
@@ -196,10 +217,19 @@ def view(
     # Views which do not have any predicates get a score of
     # sys.maxint, meaning that they will be tried very last.
 
+    predicates = []
+    weight = sys.maxint
+
+    if xhr:
+        def xhr_predicate(context, request):
+            return request.is_xhr
+        weight = weight - 10
+        predicates.append(xhr_predicate)
+
     if request_method is not None:
         def request_method_predicate(context, request):
             return request.method == request_method
-        weight = weight - 10
+        weight = weight - 20
         predicates.append(request_method_predicate)
 
     if request_param is not None:
@@ -210,13 +240,35 @@ def view(
             if request_param_val is None:
                 return request_param in request.params
             return request.params.get(request_param) == request_param_val
-        weight = weight - 20
+        weight = weight - 30
         predicates.append(request_param_predicate)
 
+    if header is not None:
+        header_name = header
+        header_val = None
+        if ':' in header:
+            header_name, header_val = header.split(':', 1)
+            try:
+                header_val = re.compile(header_val)
+            except re.error, why:
+                raise ConfigurationError(why[0])
+        def header_predicate(context, request):
+            if header_val is None:
+                return header_name in request.headers
+            val = request.headers.get(header_name)
+            return header_val.match(val) is not None
+        predicates.append(header_predicate)
+
+    if accept is not None:
+        def accept_predicate(context, request):
+            return accept in request.accept
+        weight = weight - 40
+        predicates.append(accept_predicate)
+
     if containment is not None:
         def containment_predicate(context, request):
             return find_interface(context, containment) is not None
-        weight = weight - 30
+        weight = weight - 50
         predicates.append(containment_predicate)
 
     # this will be == sys.maxint if no predicates
@@ -272,7 +324,8 @@ def view(
                                name, _context.info)
     _context.action(
         discriminator = ('view', for_, name, request_type, IView, containment,
-                         request_param, request_method, route_name, attr),
+                         request_param, request_method, route_name, attr,
+                         xhr, accept, header),
         callable = register,
         args = (),
         )
@@ -482,6 +535,9 @@ class IRouteDirective(Interface):
         required=False)
     view_attr = TextLine(title=u'view_attr', required=False)
     view_renderer = TextLine(title=u'view_renderer', required=False)
+    view_header = TextLine(title=u'view_header', required=False)
+    view_accept = TextLine(title=u'view_accept', required=False)
+    view_xhr = Bool(title=u'view_xhr', required=False)
     # alias for "view_for"
     for_ = GlobalObject(title=u'for', required=False)
     # alias for "view_permission"
@@ -500,6 +556,12 @@ class IRouteDirective(Interface):
     attr = TextLine(title=u'attr', required=False)
     # alias for "view_renderer"
     renderer = TextLine(title=u'renderer', required=False)
+    # alias for "view_header"
+    header = TextLine(title=u'header', required=False)
+    # alias for "view_accept"
+    accept = TextLine(title=u'accept', required=False)
+    # alias for "view_xhr"
+    xhr = Bool(title=u'xhr', required=False)
 
 class IRouteRequirementDirective(Interface):
     """ The interface for the ``requirement`` route subdirective """
@@ -513,7 +575,8 @@ def route(_context, name, path, view=None, view_for=None,
           request_method=None, view_request_method=None,
           request_param=None, view_request_param=None, containment=None,
           view_containment=None, attr=None, view_attr=None, renderer=None,
-          view_renderer=None):
+          view_renderer=None, header=None, view_header=None, accept=None,
+          view_accept=None, xhr=False, view_xhr=False):
     """ Handle ``route`` ZCML directives
     """
     # the strange ordering of the request kw args above is for b/w
@@ -526,6 +589,9 @@ def route(_context, name, path, view=None, view_for=None,
     containment = view_containment or containment
     attr = view_attr or attr
     renderer = view_renderer or renderer
+    header = view_header or header
+    accept = view_accept or accept
+    xhr = view_xhr or xhr
 
     sm = getSiteManager()
     
@@ -545,7 +611,8 @@ def route(_context, name, path, view=None, view_for=None,
         _view(_context, permission=permission, for_=for_, view=view, name='',
               request_type=request_type, route_name=name, 
               request_method=request_method, request_param=request_param,
-              containment=containment, attr=attr, renderer=renderer)
+              containment=containment, attr=attr, renderer=renderer,
+              header=header, accept=accept, xhr=xhr)
 
     _context.action(
         discriminator = ('route', name),
@@ -641,12 +708,16 @@ class BFGViewGrokker(martian.InstanceGrokker):
             wrapper = settings['wrapper_viewname']
             attr = settings['attr']
             renderer = settings['renderer']
+            xhr = settings['xhr']
+            accept = settings['accept']
+            header = settings['header']
             context = kw['context']
             view(context, permission=permission, for_=for_,
                  view=obj, name=name, request_type=request_type,
                  route_name=route_name, request_method=request_method,
                  request_param=request_param, containment=containment,
-                 attr=attr, renderer=renderer, wrapper=wrapper)
+                 attr=attr, renderer=renderer, wrapper=wrapper,
+                 xhr=xhr, accept=accept, header=header)
             return True
         return False