Merge lp:~rackspace-titan/nova/osapi-serialization into lp:~hudson-openstack/nova/trunk

[Brian Waldon]

- move osapi-specific wsgi code from nova/wsgi.py to nova/api/openstack/wsgi.py
- refactor wsgi modules to use more object-oriented approach to wsgi request handling:
    - Resource object steps up to original Controller position
    - Resource coordinates deserialization, dispatch to controller, serialization
    - serialization and deserialization broken down to be more testable/flexible

- this will definitely help fixing current serialization-related bugs
- this paves the way for schema validation to be implemented elegantly

[Mark Washenberger (markwash)]

Overall, I'm quite pleased. This is very much the direction I was hoping to go with the serialization blueprint and you've done a good job of handling some of the trickier details. This approach is going to be a big help as we go move towards adding better support for xml requests in particular.

- Thanks for giving my nasty one-off deserializer for server create requests a home.

- I look forward to seeing how we can build on this with request validation.

Nits, Information, and Issues:

- I like the convenience functions for creating Resources for each entry in the mapper. But a factory is usually an object, not a function. Maybe the controller module functions should be called 'get_resource()' or 'create_resource()' ?

- I see that the approach we take with extensions leans on the serialization components you are changing. However, I think it might be better if we don't reuse Resources for extensions. Rather, we might want to reuse the serializer and deserializer directly. Does this sound feasible?

- It seems like an unnecessary duplication to pass in both the request object and the deserialized body of that request to the controller. Mostly it seems like controllers use the request object to get access to the nova.context object. Perhaps we could extract context from the request and just pass in the context and the body? If that is the case, we could also rename the body variable to "request" which would be more intuitive to me. This change might cause problems with the extensions, which seem to need access to the full request--which is partly why I propose that we pull Resource out of the extensions module.

- I think you have some conflicts to resolve from the request extensions branch that just merged into trunk.

review: Needs Fixing

[Brian Waldon (bcwaldon)]

 > - I like the convenience functions for creating Resources for each entry in
> the mapper. But a factory is usually an object, not a function. Maybe the
> controller module functions should be called 'get_resource()' or
> 'create_resource()' ?

Good point. I renamed resource_factory to create_resource.

> - I see that the approach we take with extensions leans on the serialization
> components you are changing. However, I think it might be better if we don't
> reuse Resources for extensions. Rather, we might want to reuse the serializer
> and deserializer directly. Does this sound feasible?
>
> - It seems like an unnecessary duplication to pass in both the request object
> and the deserialized body of that request to the controller. Mostly it seems
> like controllers use the request object to get access to the nova.context
> object. Perhaps we could extract context from the request and just pass in the
> context and the body? If that is the case, we could also rename the body
> variable to "request" which would be more intuitive to me. This change might
> cause problems with the extensions, which seem to need access to the full
> request--which is partly why I propose that we pull Resource out of the
> extensions module.

I am definitely for all this, but I feel it is out of scope. After addressing how much will have to be refactored to accomplish the goal here, I would love to do this as a separate branch. Thoughts?

> - I think you have some conflicts to resolve from the request extensions
> branch that just merged into trunk.

Took care of this.

I also removed some obsolete code in a few places.

[Mark Washenberger (markwash)]

> I am definitely for all this, but I feel it is out of scope. After addressing
> how much will have to be refactored to accomplish the goal here, I would love
> to do this as a separate branch. Thoughts?

I agree--it looks like the controller functions are making enough diverse usage
of the request object itself that it is hard to find a good seam for this change
right now.

Apart from all that, this looks great to me. It very much accomplishes the goal that I can add a new controller with arbitrary requests and responses without having to shoe-horn them into the existing default xml serialization code.

review: Approve

[lp:~rackspace-titan/nova/osapi-serialization]

1085. By Brian Waldon on 2011-05-26

merging trunk

[Ed Leafe (ed-leafe)]

The try/except structure in diff lines 1865-68 is awkward: only the lines that could cause the exception should be in the block. Also, there is a mix of the try/except approach and the 'if' test approach for checking keys. I recommend sticking with try/except, using something more like:

    def get_action_args(self, request_environment):
        """Parse dictionary created by routes library."""
        args = request_environment['wsgiorg.routing_args'][1].copy()
        try:
            del args['format']
        except KeyError:
            pass
        try:
            del args['controller']
        except KeyError:
            return {}
        return args
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Line 1878: Bare excepts and/or catching the base Exception class should not be used. Catch the specific exception type, which in this case is probably an AttrbuteError. If that's correct, the whole structure could be written more simply as:
    action_method = getattr(self, action, self.default)
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Diff lines 1928 & 1946 should not be comparing type(x) to a type; instead, use isinstance().
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Diff line 2003: should be catching KeyError, not a base Exception.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Diff line 2034: multiple format placeholders should use the mapping style. See https://bugs.launchpad.net/nova/+bug/703041 for explanation.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

2045: use isinstance for type checking
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

2994: grammar nit: change to: "well and have your controller be a controller that will route"
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

A more general comment about formatting: there are multiple places where formatting seems more apropos to Javascript or C++ than Python; one example:

    def test_get_action_args(self):
        env = {
            'wsgiorg.routing_args': [None, {
                'controller': None,
                'format': None,
                'action': 'update',
                'id': 12,
            }],
        }

Normally continued lines are to be minimized, and when necessary, should be at a consistent level of indentation. Most typical is 2 levels of indentation, but there are other 'standards', and it's most important to be consistent to make the code readable. Outdenting closing brackets/parens is discouraged in Python. You don't need to change the code, since this style is so prevalent in these scripts, but in the future we should strive for a more Pythonic and less Javascript-y style.

review: Needs Fixing

[Brian Waldon (bcwaldon)]

> The try/except structure in diff lines 1865-68 is awkward: only the lines that
> could cause the exception should be in the block. Also, there is a mix of the
> try/except approach and the 'if' test approach for checking keys. I recommend
> sticking with try/except, using something more like:
>
> def get_action_args(self, request_environment):
> """Parse dictionary created by routes library."""
> args = request_environment['wsgiorg.routing_args'][1].copy()
> try:
> del args['format']
> except KeyError:
> pass
> try:
> del args['controller']
> except KeyError:
> return {}
> return args

Consistency is definitely a good thing to have. I updated the conditionals you mentioned with try/except blocks.

> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
>
> Line 1878: Bare excepts and/or catching the base Exception class should not be
> used. Catch the specific exception type, which in this case is probably an
> AttrbuteError. If that's correct, the whole structure could be written more
> simply as:
> action_method = getattr(self, action, self.default)

Good point. I typically use Exception when I don't know what exactly I may need to catch. Like you said, in this case I will only have to catch AttributeError. I changed the "except Exception" cases to be more specific across the module.

> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
>
> Diff lines 1928 & 1946 should not be comparing type(x) to a type; instead, use
> isinstance().

So these are "legacy" conditionals that have been working here since before I was on the project. This branch is targeted at refactoring the organization of the wsgi-related objects, not rewriting our generic xml serialization. After hearing that, are you okay with me leaving it?

> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
>
> Diff line 2003: should be catching KeyError, not a base Exception.

Fixed.

> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
>
> Diff line 2034: multiple format placeholders should use the mapping style. See
> https://bugs.launchpad.net/nova/+bug/703041 for explanation.

Well this string isn't i18n'd, but I did it for you anyways :)

> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
>
> 2045: use isinstance for type checking

This is another one of those legacy conditionals. I would love to solve this more elegantly in a future branch, possibly once we decide if we are going towards objects for our data models (instead of the dict it is checking for now).

> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
>
> 2994: grammar nit: change to: "well and have your controller be a controller
> that will route"

I should have caught that. Cleaned it up a bit.

> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
>
> A more general comment about formatting: there are multiple places where
> formatting seems more apropos to Javascript or C++ than Python; one example:
>
> def test_get_action_args(self):
> ...

[lp:~rackspace-titan/nova/osapi-serialization]

1086. By Brian Waldon on 2011-05-26

review fixups

[Ed Leafe (ed-leafe)]

>> Diff lines 1928 & 1946 should not be comparing type(x) to a type; instead, use
>> isinstance().

> So these are "legacy" conditionals that have been working here since before I was
> on the project. This branch is targeted at refactoring the organization of the
> wsgi-related objects, not rewriting our generic xml serialization. After hearing
> that, are you okay with me leaving it?

If you add a #TODO to those lines, sure.

>> If that's correct, the whole structure could be written more
>> simply as:
>> action_method = getattr(self, action, self.default)

> Good point. I typically use Exception when I don't know what exactly I may need to catch.

Trick: what you do in those cases is write it:
    except Exception as e:
        print "EXCEPTION", type(e)
...and then run the test for that code, passing in the bad condition that would trigger the exception. Once it's triggered, you'll know the type, and can change the code to catch the correct exception class.

I still think that you should change the lines (1787 and 1881) from:
    try:
        action_method = getattr(self, action)
    except (AttributeError, TypeError):
        action_method = self.default
to:
    action_method = getattr(self, action, self.default)
After all, that's what the default parameter for getattr() is there for!

[lp:~rackspace-titan/nova/osapi-serialization]

1087. By Brian Waldon on 2011-05-26

cleaning up getattr calls with default param

[Brian Waldon (bcwaldon)]

> >> Diff lines 1928 & 1946 should not be comparing type(x) to a type; instead,
> use
> >> isinstance().
>
> > So these are "legacy" conditionals that have been working here since before
> I was
> > on the project. This branch is targeted at refactoring the organization of
> the
> > wsgi-related objects, not rewriting our generic xml serialization. After
> hearing
> > that, are you okay with me leaving it?
>
> If you add a #TODO to those lines, sure.

I'm not sure what I would say the TODO is. I don't see a clear path to "fix" this, and I think most people could argue both sides of the type vs. isinstance debate.

> >> If that's correct, the whole structure could be written more
> >> simply as:
> >> action_method = getattr(self, action, self.default)
>
> > Good point. I typically use Exception when I don't know what exactly I may
> need to catch.
>
> Trick: what you do in those cases is write it:
> except Exception as e:
> print "EXCEPTION", type(e)
> ...and then run the test for that code, passing in the bad condition that
> would trigger the exception. Once it's triggered, you'll know the type, and
> can change the code to catch the correct exception class.

By not knowing the type, I am referring more to the case where literally anything could be thrown. For example, a nova.api.openstack.wsgi.Controller object could define its create method to throw literally anything.

> I still think that you should change the lines (1787 and 1881) from:
> try:
> action_method = getattr(self, action)
> except (AttributeError, TypeError):
> action_method = self.default
> to:
> action_method = getattr(self, action, self.default)
> After all, that's what the default parameter for getattr() is there for!

Wow, I need to read over the built-ins doc. I had no idea there was a default parameter. Fixed!

[Ed Leafe (ed-leafe)]

> > If you add a #TODO to those lines, sure.
>
> I'm not sure what I would say the TODO is. I don't see a clear path to "fix"
> this, and I think most people could argue both sides of the type vs.
> isinstance debate.

type() has known limitations with old-style classes; isinstance() does not. Additionally, type() check does not take into account subclassing; isinstance() does. There is no clean way to check for a string object with type() due to types.StringType and types.UnicodeType; you can use isinstance(val, basestring) to check for all string types.

So who are the people who are arguing both sides? :)

[Brian Waldon (bcwaldon)]

> type() has known limitations with old-style classes; isinstance() does not.
> Additionally, type() check does not take into account subclassing;
> isinstance() does. There is no clean way to check for a string object with
> type() due to types.StringType and types.UnicodeType; you can use
> isinstance(val, basestring) to check for all string types.

So the best thing to do in this case would be to use the built-in interfaces. First assume the 'data' variable is a dict and attempt to use it as such. When that doesn't work out, assume it is a list. When that doesn't work we end up just adding it as an xml text node. I'm going to stand by my point that I don't want to touch the code you are referring to since it is serving its purpose without issue. If someone wants to refactor the actual xml-specific serializer, I welcome it :)

I went to add a TODO on the third use of type(), and realized there is already a note there mentioning a need to refactor.

[Ed Leafe (ed-leafe)]

> So the best thing to do in this case would be to use the built-in interfaces.

No, the best thing to do would be to change:
    if type(data) is list:
to:
    if isinstance(data, list):

> First assume the 'data' variable is a dict and attempt to use it as such. When
> that doesn't work out, assume it is a list. When that doesn't work we end up
> just adding it as an xml text node. I'm going to stand by my point that I
> don't want to touch the code you are referring to since it is serving its
> purpose without issue. If someone wants to refactor the actual xml-specific
> serializer, I welcome it :)

Since the code is suboptimal but not incorrect, it is not imperative that it be changed, which is why I suggested simply adding a #TODO comment. I'm not sure why adding a comment about a better way to write the code counts as "touching" the code; that's what I thought the whole point of #TODOs were.

review: Approve

[lp:~rackspace-titan/nova/osapi-serialization]

1088. By Brian Waldon on 2011-05-26

adding TODOs per dabo's review

[Brian Waldon (bcwaldon)]

Had a discussion with Ed and resolved the discussion above. Added the TODOs.

[Dan Prince (dan-prince)]

Approve. Looks good to me. Well done.

review: Approve

=== modified file 'nova/api/direct.py'
--- nova/api/direct.py	2011-04-11 16:34:19 +0000
+++ nova/api/direct.py	2011-05-26 21:32:29 +0000
@@ -42,6 +42,7 @@
 from nova import flags
 from nova import utils
 from nova import wsgi
+import nova.api.openstack.wsgi
 
 
 # Global storage for registering modules.
@@ -251,7 +252,7 @@
         return self._methods[method]
 
 
-class ServiceWrapper(wsgi.Controller):
+class ServiceWrapper(object):
     """Wrapper to dynamically povide a WSGI controller for arbitrary objects.
 
     With lightweight introspection allows public methods on the object to
@@ -265,7 +266,7 @@
     def __init__(self, service_handle):
         self.service_handle = service_handle
 
-    @webob.dec.wsgify(RequestClass=wsgi.Request)
+    @webob.dec.wsgify(RequestClass=nova.api.openstack.wsgi.Request)
     def __call__(self, req):
         arg_dict = req.environ['wsgiorg.routing_args'][1]
         action = arg_dict['action']
@@ -289,8 +290,11 @@
 
         try:
             content_type = req.best_match_content_type()
-            default_xmlns = self.get_default_xmlns(req)
-            return self._serialize(result, content_type, default_xmlns)
+            serializer = {
+              'application/xml': nova.api.openstack.wsgi.XMLDictSerializer(),
+              'application/json': nova.api.openstack.wsgi.JSONDictSerializer(),
+            }[content_type]
+            return serializer.serialize(result)
         except:
             raise exception.Error("returned non-serializable type: %s"
                                   % result)
 
=== modified file 'nova/api/openstack/__init__.py'
--- nova/api/openstack/__init__.py	2011-05-13 15:17:19 +0000
+++ nova/api/openstack/__init__.py	2011-05-26 21:32:29 +0000
@@ -26,7 +26,7 @@
 
 from nova import flags
 from nova import log as logging
-from nova import wsgi
+from nova import wsgi as base_wsgi
 from nova.api.openstack import accounts
 from nova.api.openstack import faults
 from nova.api.openstack import backup_schedules
@@ -40,6 +40,7 @@
 from nova.api.openstack import server_metadata
 from nova.api.openstack import shared_ip_groups
 from nova.api.openstack import users
+from nova.api.openstack import wsgi
 from nova.api.openstack import zones
 
 
@@ -50,7 +51,7 @@
     'When True, this API service will accept admin operations.')
 
 
-class FaultWrapper(wsgi.Middleware):
+class FaultWrapper(base_wsgi.Middleware):
     """Calls down the middleware stack, making exceptions into faults."""
 
     @webob.dec.wsgify(RequestClass=wsgi.Request)
@@ -63,7 +64,7 @@
             return faults.Fault(exc)
 
 
-class APIRouter(wsgi.Router):
+class APIRouter(base_wsgi.Router):
     """
     Routes requests on the OpenStack API to the appropriate controller
     and method.
@@ -97,19 +98,21 @@
             server_members['reset_network'] = 'POST'
             server_members['inject_network_info'] = 'POST'
 
-            mapper.resource("zone", "zones", controller=zones.Controller(),
+            mapper.resource("zone", "zones",
+                        controller=zones.create_resource(),
                         collection={'detail': 'GET', 'info': 'GET',
                                     'select': 'GET'})
 
-            mapper.resource("user", "users", controller=users.Controller(),
+            mapper.resource("user", "users",
+                        controller=users.create_resource(),
                         collection={'detail': 'GET'})
 
             mapper.resource("account", "accounts",
-                            controller=accounts.Controller(),
+                            controller=accounts.create_resource(),
                             collection={'detail': 'GET'})
 
         mapper.resource("console", "consoles",
-                        controller=consoles.Controller(),
+                        controller=consoles.create_resource(),
                         parent_resource=dict(member_name='server',
                         collection_name='servers'))
 
@@ -122,31 +125,31 @@
     def _setup_routes(self, mapper):
         super(APIRouterV10, self)._setup_routes(mapper)
         mapper.resource("server", "servers",
-                        controller=servers.ControllerV10(),
+                        controller=servers.create_resource('1.0'),
                         collection={'detail': 'GET'},
                         member=self.server_members)
 
         mapper.resource("image", "images",
-                        controller=images.ControllerV10(),
+                        controller=images.create_resource('1.0'),
                         collection={'detail': 'GET'})
 
         mapper.resource("flavor", "flavors",
-                        controller=flavors.ControllerV10(),
+                        controller=flavors.create_resource('1.0'),
                         collection={'detail': 'GET'})
 
         mapper.resource("shared_ip_group", "shared_ip_groups",
                         collection={'detail': 'GET'},
-                        controller=shared_ip_groups.Controller())
+                        controller=shared_ip_groups.create_resource())
 
         mapper.resource("backup_schedule", "backup_schedule",
-                        controller=backup_schedules.Controller(),
+                        controller=backup_schedules.create_resource(),
                         parent_resource=dict(member_name='server',
                         collection_name='servers'))
 
         mapper.resource("limit", "limits",
-                        controller=limits.LimitsControllerV10())
+                        controller=limits.create_resource('1.0'))
 
-        mapper.resource("ip", "ips", controller=ips.Controller(),
+        mapper.resource("ip", "ips", controller=ips.create_resource(),
                         collection=dict(public='GET', private='GET'),
                         parent_resource=dict(member_name='server',
                                              collection_name='servers'))
@@ -158,27 +161,27 @@
     def _setup_routes(self, mapper):
         super(APIRouterV11, self)._setup_routes(mapper)
         mapper.resource("server", "servers",
-                        controller=servers.ControllerV11(),
+                        controller=servers.create_resource('1.1'),
                         collection={'detail': 'GET'},
                         member=self.server_members)
 
         mapper.resource("image", "images",
-                        controller=images.ControllerV11(),
+                        controller=images.create_resource('1.1'),
                         collection={'detail': 'GET'})
 
         mapper.resource("image_meta", "meta",
-                        controller=image_metadata.Controller(),
+                        controller=image_metadata.create_resource(),
                         parent_resource=dict(member_name='image',
                         collection_name='images'))
 
         mapper.resource("server_meta", "meta",
-                        controller=server_metadata.Controller(),
+                        controller=server_metadata.create_resource(),
                         parent_resource=dict(member_name='server',
                         collection_name='servers'))
 
         mapper.resource("flavor", "flavors",
-                        controller=flavors.ControllerV11(),
+                        controller=flavors.create_resource('1.1'),
                         collection={'detail': 'GET'})
 
         mapper.resource("limit", "limits",
-                        controller=limits.LimitsControllerV11())
+                        controller=limits.create_resource('1.1'))
 
=== modified file 'nova/api/openstack/accounts.py'
--- nova/api/openstack/accounts.py	2011-04-27 21:03:05 +0000
+++ nova/api/openstack/accounts.py	2011-05-26 21:32:29 +0000
@@ -20,8 +20,9 @@
 from nova import log as logging
 
 from nova.auth import manager
-from nova.api.openstack import common
 from nova.api.openstack import faults
+from nova.api.openstack import wsgi
+
 
 FLAGS = flags.FLAGS
 LOG = logging.getLogger('nova.api.openstack')
@@ -34,12 +35,7 @@
                 manager=account.project_manager_id)
 
 
-class Controller(common.OpenstackController):
-
-    _serialization_metadata = {
-        'application/xml': {
-            "attributes": {
-                "account": ["id", "name", "description", "manager"]}}}
+class Controller(object):
 
     def __init__(self):
         self.manager = manager.AuthManager()
@@ -66,20 +62,33 @@
         self.manager.delete_project(id)
         return {}
 
-    def create(self, req):
+    def create(self, req, body):
         """We use update with create-or-update semantics
            because the id comes from an external source"""
         raise faults.Fault(webob.exc.HTTPNotImplemented())
 
-    def update(self, req, id):
+    def update(self, req, id, body):
         """This is really create or update."""
         self._check_admin(req.environ['nova.context'])
-        env = self._deserialize(req.body, req.get_content_type())
-        description = env['account'].get('description')
-        manager = env['account'].get('manager')
+        description = body['account'].get('description')
+        manager = body['account'].get('manager')
         try:
             account = self.manager.get_project(id)
             self.manager.modify_project(id, manager, description)
         except exception.NotFound:
             account = self.manager.create_project(id, manager, description)
         return dict(account=_translate_keys(account))
+
+
+def create_resource():
+    metadata = {
+        "attributes": {
+            "account": ["id", "name", "description", "manager"],
+        },
+    }
+
+    serializers = {
+        'application/xml': wsgi.XMLDictSerializer(metadata=metadata),
+    }
+
+    return wsgi.Resource(Controller(), serializers=serializers)
 
=== modified file 'nova/api/openstack/backup_schedules.py'
--- nova/api/openstack/backup_schedules.py	2011-03-30 17:05:06 +0000
+++ nova/api/openstack/backup_schedules.py	2011-05-26 21:32:29 +0000
@@ -19,9 +19,8 @@
 
 from webob import exc
 
-from nova.api.openstack import common
 from nova.api.openstack import faults
-import nova.image.service
+from nova.api.openstack import wsgi
 
 
 def _translate_keys(inst):
@@ -29,14 +28,9 @@
     return dict(backupSchedule=inst)
 
 
-class Controller(common.OpenstackController):
+class Controller(object):
     """ The backup schedule API controller for the Openstack API """
 
-    _serialization_metadata = {
-        'application/xml': {
-            'attributes': {
-                'backupSchedule': []}}}
-
     def __init__(self):
         pass
 
@@ -48,7 +42,7 @@
         """ Returns a single backup schedule for a given instance """
         return faults.Fault(exc.HTTPNotImplemented())
 
-    def create(self, req, server_id):
+    def create(self, req, server_id, body):
         """ No actual update method required, since the existing API allows
         both create and update through a POST """
         return faults.Fault(exc.HTTPNotImplemented())
@@ -56,3 +50,18 @@
     def delete(self, req, server_id, id):
         """ Deletes an existing backup schedule """
         return faults.Fault(exc.HTTPNotImplemented())
+
+
+def create_resource():
+    metadata = {
+        'attributes': {
+            'backupSchedule': [],
+        },
+    }
+
+    serializers = {
+        'application/xml': wsgi.XMLDictSerializer(xmlns=wsgi.XMLNS_V10,
+                                                  metadata=metadata),
+    }
+
+    return wsgi.Resource(Controller(), serializers=serializers)
 
=== modified file 'nova/api/openstack/common.py'
--- nova/api/openstack/common.py	2011-05-02 20:14:41 +0000
+++ nova/api/openstack/common.py	2011-05-26 21:32:29 +0000
@@ -23,7 +23,6 @@
 from nova import exception
 from nova import flags
 from nova import log as logging
-from nova import wsgi
 
 
 LOG = logging.getLogger('nova.api.openstack.common')
@@ -146,9 +145,3 @@
     except:
         LOG.debug(_("Error extracting id from href: %s") % href)
         raise webob.exc.HTTPBadRequest(_('could not parse id from href'))
-
-
-class OpenstackController(wsgi.Controller):
-    def get_default_xmlns(self, req):
-        # Use V10 by default
-        return XML_NS_V10
 
=== modified file 'nova/api/openstack/consoles.py'
--- nova/api/openstack/consoles.py	2011-03-30 17:05:06 +0000
+++ nova/api/openstack/consoles.py	2011-05-26 21:32:29 +0000
@@ -19,8 +19,8 @@
 
 from nova import console
 from nova import exception
-from nova.api.openstack import common
 from nova.api.openstack import faults
+from nova.api.openstack import wsgi
 
 
 def _translate_keys(cons):
@@ -43,17 +43,11 @@
     return dict(console=info)
 
 
-class Controller(common.OpenstackController):
-    """The Consoles Controller for the Openstack API"""
-
-    _serialization_metadata = {
-        'application/xml': {
-            'attributes': {
-                'console': []}}}
+class Controller(object):
+    """The Consoles controller for the Openstack API"""
 
     def __init__(self):
         self.console_api = console.API()
-        super(Controller, self).__init__()
 
     def index(self, req, server_id):
         """Returns a list of consoles for this instance"""
@@ -63,9 +57,8 @@
         return dict(consoles=[_translate_keys(console)
                               for console in consoles])
 
-    def create(self, req, server_id):
+    def create(self, req, server_id, body):
         """Creates a new console"""
-        #info = self._deserialize(req.body, req.get_content_type())
         self.console_api.create_console(
                                 req.environ['nova.context'],
                                 int(server_id))
@@ -94,3 +87,17 @@
         except exception.NotFound:
             return faults.Fault(exc.HTTPNotFound())
         return exc.HTTPAccepted()
+
+
+def create_resource():
+    metadata = {
+        'attributes': {
+            'console': [],
+        },
+    }
+
+    serializers = {
+        'application/xml': wsgi.XMLDictSerializer(metadata=metadata),
+    }
+
+    return wsgi.Resource(Controller(), serializers=serializers)
 
=== modified file 'nova/api/openstack/contrib/volumes.py'
--- nova/api/openstack/contrib/volumes.py	2011-04-19 09:54:47 +0000
+++ nova/api/openstack/contrib/volumes.py	2011-05-26 21:32:29 +0000
@@ -22,7 +22,6 @@
 from nova import flags
 from nova import log as logging
 from nova import volume
-from nova import wsgi
 from nova.api.openstack import common
 from nova.api.openstack import extensions
 from nova.api.openstack import faults
@@ -64,7 +63,7 @@
     return d
 
 
-class VolumeController(wsgi.Controller):
+class VolumeController(object):
     """The Volumes API controller for the OpenStack API."""
 
     _serialization_metadata = {
@@ -124,15 +123,14 @@
         res = [entity_maker(context, vol) for vol in limited_list]
         return {'volumes': res}
 
-    def create(self, req):
+    def create(self, req, body):
         """Creates a new volume."""
         context = req.environ['nova.context']
 
-        env = self._deserialize(req.body, req.get_content_type())
-        if not env:
+        if not body:
             return faults.Fault(exc.HTTPUnprocessableEntity())
 
-        vol = env['volume']
+        vol = body['volume']
         size = vol['size']
         LOG.audit(_("Create volume of %s GB"), size, context=context)
         new_volume = self.volume_api.create(context, size,
@@ -175,7 +173,7 @@
     return d
 
 
-class VolumeAttachmentController(wsgi.Controller):
+class VolumeAttachmentController(object):
     """The volume attachment API controller for the Openstack API.
 
     A child resource of the server.  Note that we use the volume id
@@ -219,17 +217,16 @@
         return {'volumeAttachment': _translate_attachment_detail_view(context,
                                                                       vol)}
 
-    def create(self, req, server_id):
+    def create(self, req, server_id, body):
         """Attach a volume to an instance."""
         context = req.environ['nova.context']
 
-        env = self._deserialize(req.body, req.get_content_type())
-        if not env:
+        if not body:
             return faults.Fault(exc.HTTPUnprocessableEntity())
 
         instance_id = server_id
-        volume_id = env['volumeAttachment']['volumeId']
-        device = env['volumeAttachment']['device']
+        volume_id = body['volumeAttachment']['volumeId']
+        device = body['volumeAttachment']['device']
 
         msg = _("Attach volume %(volume_id)s to instance %(server_id)s"
                 " at %(device)s") % locals()
@@ -259,7 +256,7 @@
         # TODO(justinsb): How do I return "accepted" here?
         return {'volumeAttachment': attachment}
 
-    def update(self, _req, _server_id, _id):
+    def update(self, req, server_id, id, body):
         """Update a volume attachment.  We don't currently support this."""
         return faults.Fault(exc.HTTPBadRequest())
 
 
=== modified file 'nova/api/openstack/extensions.py'
--- nova/api/openstack/extensions.py	2011-05-17 03:14:51 +0000
+++ nova/api/openstack/extensions.py	2011-05-26 21:32:29 +0000
@@ -27,9 +27,10 @@
 from nova import exception
 from nova import flags
 from nova import log as logging
-from nova import wsgi
+from nova import wsgi as base_wsgi
 from nova.api.openstack import common
 from nova.api.openstack import faults
+from nova.api.openstack import wsgi
 
 
 LOG = logging.getLogger('extensions')
@@ -115,28 +116,34 @@
         return request_exts
 
 
-class ActionExtensionController(common.OpenstackController):
-
+class ActionExtensionController(object):
     def __init__(self, application):
-
         self.application = application
         self.action_handlers = {}
 
     def add_action(self, action_name, handler):
         self.action_handlers[action_name] = handler
 
-    def action(self, req, id):
-
-        input_dict = self._deserialize(req.body, req.get_content_type())
+    def action(self, req, id, body):
         for action_name, handler in self.action_handlers.iteritems():
-            if action_name in input_dict:
-                return handler(input_dict, req, id)
+            if action_name in body:
+                return handler(body, req, id)
         # no action handler found (bump to downstream application)
         res = self.application
         return res
 
 
-class RequestExtensionController(common.OpenstackController):
+class ActionExtensionResource(wsgi.Resource):
+
+    def __init__(self, application):
+        controller = ActionExtensionController(application)
+        super(ActionExtensionResource, self).__init__(controller)
+
+    def add_action(self, action_name, handler):
+        self.controller.add_action(action_name, handler)
+
+
+class RequestExtensionController(object):
 
     def __init__(self, application):
         self.application = application
@@ -153,7 +160,17 @@
         return res
 
 
-class ExtensionController(common.OpenstackController):
+class RequestExtensionResource(wsgi.Resource):
+
+    def __init__(self, application):
+        controller = RequestExtensionController(application)
+        super(RequestExtensionResource, self).__init__(controller)
+
+    def add_handler(self, handler):
+        self.controller.add_handler(handler)
+
+
+class ExtensionsResource(wsgi.Resource):
 
     def __init__(self, extension_manager):
         self.extension_manager = extension_manager
@@ -186,7 +203,7 @@
         raise faults.Fault(webob.exc.HTTPNotFound())
 
 
-class ExtensionMiddleware(wsgi.Middleware):
+class ExtensionMiddleware(base_wsgi.Middleware):
     """Extensions middleware for WSGI."""
     @classmethod
     def factory(cls, global_config, **local_config):
@@ -195,43 +212,43 @@
             return cls(app, **local_config)
         return _factory
 
-    def _action_ext_controllers(self, application, ext_mgr, mapper):
-        """Return a dict of ActionExtensionController-s by collection."""
-        action_controllers = {}
+    def _action_ext_resources(self, application, ext_mgr, mapper):
+        """Return a dict of ActionExtensionResource-s by collection."""
+        action_resources = {}
         for action in ext_mgr.get_actions():
-            if not action.collection in action_controllers.keys():
-                controller = ActionExtensionController(application)
+            if not action.collection in action_resources.keys():
+                resource = ActionExtensionResource(application)
                 mapper.connect("/%s/:(id)/action.:(format)" %
                                 action.collection,
                                 action='action',
-                                controller=controller,
+                                controller=resource,
                                 conditions=dict(method=['POST']))
                 mapper.connect("/%s/:(id)/action" % action.collection,
                                 action='action',
-                                controller=controller,
+                                controller=resource,
                                 conditions=dict(method=['POST']))
-                action_controllers[action.collection] = controller
-
-        return action_controllers
-
-    def _request_ext_controllers(self, application, ext_mgr, mapper):
-        """Returns a dict of RequestExtensionController-s by collection."""
-        request_ext_controllers = {}
+                action_resources[action.collection] = resource
+
+        return action_resources
+
+    def _request_ext_resources(self, application, ext_mgr, mapper):
+        """Returns a dict of RequestExtensionResource-s by collection."""
+        request_ext_resources = {}
         for req_ext in ext_mgr.get_request_extensions():
-            if not req_ext.key in request_ext_controllers.keys():
-                controller = RequestExtensionController(application)
+            if not req_ext.key in request_ext_resources.keys():
+                resource = RequestExtensionResource(application)
                 mapper.connect(req_ext.url_route + '.:(format)',
                                 action='process',
-                                controller=controller,
+                                controller=resource,
                                 conditions=req_ext.conditions)
 
                 mapper.connect(req_ext.url_route,
                                 action='process',
-                                controller=controller,
+                                controller=resource,
                                 conditions=req_ext.conditions)
-                request_ext_controllers[req_ext.key] = controller
+                request_ext_resources[req_ext.key] = resource
 
-        return request_ext_controllers
+        return request_ext_resources
 
     def __init__(self, application, ext_mgr=None):
 
@@ -246,22 +263,22 @@
             LOG.debug(_('Extended resource: %s'),
                         resource.collection)
             mapper.resource(resource.collection, resource.collection,
-                            controller=resource.controller,
+                            controller=wsgi.Resource(resource.controller),
                             collection=resource.collection_actions,
                             member=resource.member_actions,
                             parent_resource=resource.parent)
 
         # extended actions
-        action_controllers = self._action_ext_controllers(application, ext_mgr,
+        action_resources = self._action_ext_resources(application, ext_mgr,
                                                         mapper)
         for action in ext_mgr.get_actions():
             LOG.debug(_('Extended action: %s'), action.action_name)
-            controller = action_controllers[action.collection]
-            controller.add_action(action.action_name, action.handler)
+            resource = action_resources[action.collection]
+            resource.add_action(action.action_name, action.handler)
 
         # extended requests
-        req_controllers = self._request_ext_controllers(application, ext_mgr,
-                                                            mapper)
+        req_controllers = self._request_ext_resources(application, ext_mgr,
+                                                      mapper)
         for request_ext in ext_mgr.get_request_extensions():
             LOG.debug(_('Extended request: %s'), request_ext.key)
             controller = req_controllers[request_ext.key]
@@ -313,7 +330,7 @@
         """Returns a list of ResourceExtension objects."""
         resources = []
         resources.append(ResourceExtension('extensions',
-                                            ExtensionController(self)))
+                                            ExtensionsResource(self)))
         for alias, ext in self.extensions.iteritems():
             try:
                 resources.extend(ext.get_resources())
@@ -410,7 +427,7 @@
 
 
 class RequestExtension(object):
-    """Extend requests and responses of core nova OpenStack API controllers.
+    """Extend requests and responses of core nova OpenStack API resources.
 
     Provide a way to add data to responses and handle custom request data
     that is sent to core nova OpenStack API controllers.
@@ -424,7 +441,7 @@
 
 
 class ActionExtension(object):
-    """Add custom actions to core nova OpenStack API controllers."""
+    """Add custom actions to core nova OpenStack API resources."""
 
     def __init__(self, collection, action_name, handler):
         self.collection = collection
 
=== modified file 'nova/api/openstack/faults.py'
--- nova/api/openstack/faults.py	2011-04-07 18:55:42 +0000
+++ nova/api/openstack/faults.py	2011-05-26 21:32:29 +0000
@@ -19,8 +19,7 @@
 import webob.dec
 import webob.exc
 
-from nova import wsgi
-from nova.api.openstack import common
+from nova.api.openstack import wsgi
 
 
 class Fault(webob.exc.HTTPException):
@@ -55,13 +54,21 @@
         if code == 413:
             retry = self.wrapped_exc.headers['Retry-After']
             fault_data[fault_name]['retryAfter'] = retry
+
         # 'code' is an attribute on the fault tag itself
-        metadata = {'application/xml': {'attributes': {fault_name: 'code'}}}
-        default_xmlns = common.XML_NS_V10
-        serializer = wsgi.Serializer(metadata, default_xmlns)
+        metadata = {'attributes': {fault_name: 'code'}}
+
         content_type = req.best_match_content_type()
-        self.wrapped_exc.body = serializer.serialize(fault_data, content_type)
+
+        serializer = {
+            'application/xml': wsgi.XMLDictSerializer(metadata=metadata,
+                                                      xmlns=wsgi.XMLNS_V10),
+            'application/json': wsgi.JSONDictSerializer(),
+        }[content_type]
+
+        self.wrapped_exc.body = serializer.serialize(fault_data)
         self.wrapped_exc.content_type = content_type
+
         return self.wrapped_exc
 
 
@@ -70,14 +77,6 @@
     Rate-limited request response.
     """
 
-    _serialization_metadata = {
-        "application/xml": {
-            "attributes": {
-                "overLimitFault": "code",
-            },
-        },
-    }
-
     def __init__(self, message, details, retry_time):
         """
         Initialize new `OverLimitFault` with relevant information.
@@ -97,8 +96,16 @@
         Return the wrapped exception with a serialized body conforming to our
         error format.
         """
-        serializer = wsgi.Serializer(self._serialization_metadata)
         content_type = request.best_match_content_type()
-        content = serializer.serialize(self.content, content_type)
+        metadata = {"attributes": {"overLimitFault": "code"}}
+
+        serializer = {
+            'application/xml': wsgi.XMLDictSerializer(metadata=metadata,
+                                                      xmlns=wsgi.XMLNS_V10),
+            'application/json': wsgi.JSONDictSerializer(),
+        }[content_type]
+
+        content = serializer.serialize(self.content)
         self.wrapped_exc.body = content
+
         return self.wrapped_exc
 
=== modified file 'nova/api/openstack/flavors.py'
--- nova/api/openstack/flavors.py	2011-05-06 20:13:35 +0000
+++ nova/api/openstack/flavors.py	2011-05-26 21:32:29 +0000
@@ -19,22 +19,13 @@
 
 from nova import db
 from nova import exception
-from nova.api.openstack import common
 from nova.api.openstack import views
-
-
-class Controller(common.OpenstackController):
+from nova.api.openstack import wsgi
+
+
+class Controller(object):
     """Flavor controller for the OpenStack API."""
 
-    _serialization_metadata = {
-        'application/xml': {
-            "attributes": {
-                "flavor": ["id", "name", "ram", "disk"],
-                "link": ["rel", "type", "href"],
-            }
-        }
-    }
-
     def index(self, req):
         """Return all flavors in brief."""
         items = self._get_flavors(req, is_detail=False)
@@ -71,14 +62,31 @@
 
 
 class ControllerV10(Controller):
+
     def _get_view_builder(self, req):
         return views.flavors.ViewBuilder()
 
 
 class ControllerV11(Controller):
+
     def _get_view_builder(self, req):
         base_url = req.application_url
         return views.flavors.ViewBuilderV11(base_url)
 
-    def get_default_xmlns(self, req):
-        return common.XML_NS_V11
+
+def create_resource(version='1.0'):
+    controller = {
+        '1.0': ControllerV10,
+        '1.1': ControllerV11,
+    }[version]()
+
+    xmlns = {
+        '1.0': wsgi.XMLNS_V10,
+        '1.1': wsgi.XMLNS_V11,
+    }[version]
+
+    serializers = {
+        'application/xml': wsgi.XMLDictSerializer(xmlns=xmlns),
+    }
+
+    return wsgi.Resource(controller, serializers=serializers)
 
=== modified file 'nova/api/openstack/image_metadata.py'
--- nova/api/openstack/image_metadata.py	2011-04-08 07:58:48 +0000
+++ nova/api/openstack/image_metadata.py	2011-05-26 21:32:29 +0000
@@ -20,20 +20,18 @@
 from nova import flags
 from nova import quota
 from nova import utils
-from nova import wsgi
-from nova.api.openstack import common
 from nova.api.openstack import faults
+from nova.api.openstack import wsgi
 
 
 FLAGS = flags.FLAGS
 
 
-class Controller(common.OpenstackController):
+class Controller(object):
     """The image metadata API controller for the Openstack API"""
 
     def __init__(self):
         self.image_service = utils.import_object(FLAGS.image_service)
-        super(Controller, self).__init__()
 
     def _get_metadata(self, context, image_id, image=None):
         if not image:
@@ -64,9 +62,8 @@
         else:
             return faults.Fault(exc.HTTPNotFound())
 
-    def create(self, req, image_id):
+    def create(self, req, image_id, body):
         context = req.environ['nova.context']
-        body = self._deserialize(req.body, req.get_content_type())
         img = self.image_service.show(context, image_id)
         metadata = self._get_metadata(context, image_id, img)
         if 'metadata' in body:
@@ -77,9 +74,8 @@
         self.image_service.update(context, image_id, img, None)
         return dict(metadata=metadata)
 
-    def update(self, req, image_id, id):
+    def update(self, req, image_id, id, body):
         context = req.environ['nova.context']
-        body = self._deserialize(req.body, req.get_content_type())
         if not id in body:
             expl = _('Request body and URI mismatch')
             raise exc.HTTPBadRequest(explanation=expl)
@@ -104,3 +100,11 @@
         metadata.pop(id)
         img['properties'] = metadata
         self.image_service.update(context, image_id, img, None)
+
+
+def create_resource():
+    serializers = {
+        'application/xml': wsgi.XMLDictSerializer(xmlns=wsgi.XMLNS_V11),
+    }
+
+    return wsgi.Resource(Controller(), serializers=serializers)
 
=== modified file 'nova/api/openstack/images.py'
--- nova/api/openstack/images.py	2011-04-21 17:29:11 +0000
+++ nova/api/openstack/images.py	2011-05-26 21:32:29 +0000
@@ -23,24 +23,15 @@
 from nova.api.openstack import common
 from nova.api.openstack import faults
 from nova.api.openstack.views import images as images_view
+from nova.api.openstack import wsgi
 
 
 LOG = log.getLogger('nova.api.openstack.images')
 FLAGS = flags.FLAGS
 
 
-class Controller(common.OpenstackController):
-    """Base `wsgi.Controller` for retrieving/displaying images."""
-
-    _serialization_metadata = {
-        'application/xml': {
-            "attributes": {
-                "image": ["id", "name", "updated", "created", "status",
-                          "serverId", "progress"],
-                "link": ["rel", "type", "href"],
-            },
-        },
-    }
+class Controller(object):
+    """Base controller for retrieving/displaying images."""
 
     def __init__(self, image_service=None, compute_service=None):
         """Initialize new `ImageController`.
@@ -108,21 +99,20 @@
         self._image_service.delete(context, image_id)
         return webob.exc.HTTPNoContent()
 
-    def create(self, req):
+    def create(self, req, body):
         """Snapshot a server instance and save the image.
 
         :param req: `wsgi.Request` object
         """
         context = req.environ['nova.context']
         content_type = req.get_content_type()
-        image = self._deserialize(req.body, content_type)
 
-        if not image:
+        if not body:
             raise webob.exc.HTTPBadRequest()
 
         try:
-            server_id = image["image"]["serverId"]
-            image_name = image["image"]["name"]
+            server_id = body["image"]["serverId"]
+            image_name = body["image"]["name"]
         except KeyError:
             raise webob.exc.HTTPBadRequest()
 
@@ -151,5 +141,29 @@
         base_url = request.application_url
         return images_view.ViewBuilderV11(base_url)
 
-    def get_default_xmlns(self, req):
-        return common.XML_NS_V11
+
+def create_resource(version='1.0'):
+    controller = {
+        '1.0': ControllerV10,
+        '1.1': ControllerV11,
+    }[version]()
+
+    xmlns = {
+        '1.0': wsgi.XMLNS_V10,
+        '1.1': wsgi.XMLNS_V11,
+    }[version]
+
+    metadata = {
+        "attributes": {
+            "image": ["id", "name", "updated", "created", "status",
+                      "serverId", "progress"],
+            "link": ["rel", "type", "href"],
+        },
+    }
+
+    serializers = {
+        'application/xml': wsgi.XMLDictSerializer(xmlns=xmlns,
+                                                  metadata=metadata),
+    }
+
+    return wsgi.Resource(controller, serializers=serializers)
 
=== modified file 'nova/api/openstack/ips.py'
--- nova/api/openstack/ips.py	2011-04-06 21:50:11 +0000
+++ nova/api/openstack/ips.py	2011-05-26 21:32:29 +0000
@@ -20,23 +20,14 @@
 from webob import exc
 
 import nova
+from nova.api.openstack import faults
 import nova.api.openstack.views.addresses
-from nova.api.openstack import common
-from nova.api.openstack import faults
-
-
-class Controller(common.OpenstackController):
+from nova.api.openstack import wsgi
+
+
+class Controller(object):
     """The servers addresses API controller for the Openstack API."""
 
-    _serialization_metadata = {
-        'application/xml': {
-            'list_collections': {
-                'public':  {'item_name': 'ip', 'item_key': 'addr'},
-                'private': {'item_name': 'ip', 'item_key': 'addr'},
-            },
-        },
-    }
-
     def __init__(self):
         self.compute_api = nova.compute.API()
         self.builder = nova.api.openstack.views.addresses.ViewBuilderV10()
@@ -65,8 +56,24 @@
     def show(self, req, server_id, id):
         return faults.Fault(exc.HTTPNotImplemented())
 
-    def create(self, req, server_id):
+    def create(self, req, server_id, body):
         return faults.Fault(exc.HTTPNotImplemented())
 
     def delete(self, req, server_id, id):
         return faults.Fault(exc.HTTPNotImplemented())
+
+
+def create_resource():
+    metadata = {
+        'list_collections': {
+            'public':  {'item_name': 'ip', 'item_key': 'addr'},
+            'private': {'item_name': 'ip', 'item_key': 'addr'},
+        },
+    }
+
+    serializers = {
+        'application/xml': wsgi.XMLDictSerializer(metadata=metadata,
+                                                  xmlns=wsgi.XMLNS_V10),
+    }
+
+    return wsgi.Resource(Controller(), serializers=serializers)
 
=== modified file 'nova/api/openstack/limits.py'
--- nova/api/openstack/limits.py	2011-05-19 18:08:15 +0000
+++ nova/api/openstack/limits.py	2011-05-26 21:32:29 +0000
@@ -31,10 +31,12 @@
 from webob.dec import wsgify
 
 from nova import quota
+from nova import wsgi as base_wsgi
 from nova import wsgi
 from nova.api.openstack import common
 from nova.api.openstack import faults
 from nova.api.openstack.views import limits as limits_views
+from nova.api.openstack import wsgi
 
 
 # Convenience constants for the limits dictionary passed to Limiter().
@@ -44,23 +46,11 @@
 PER_DAY = 60 * 60 * 24
 
 
-class LimitsController(common.OpenstackController):
+class LimitsController(object):
     """
     Controller for accessing limits in the OpenStack API.
     """
 
-    _serialization_metadata = {
-        "application/xml": {
-            "attributes": {
-                "limit": ["verb", "URI", "uri", "regex", "value", "unit",
-                    "resetTime", "next-available", "remaining", "name"],
-            },
-            "plurals": {
-                "rate": "limit",
-            },
-        },
-    }
-
     def index(self, req):
         """
         Return all global and rate limit information.
@@ -86,6 +76,35 @@
         return limits_views.ViewBuilderV11()
 
 
+def create_resource(version='1.0'):
+    controller = {
+        '1.0': LimitsControllerV10,
+        '1.1': LimitsControllerV11,
+    }[version]()
+
+    xmlns = {
+        '1.0': wsgi.XMLNS_V10,
+        '1.1': wsgi.XMLNS_V11,
+    }[version]
+
+    metadata = {
+        "attributes": {
+            "limit": ["verb", "URI", "uri", "regex", "value", "unit",
+                "resetTime", "next-available", "remaining", "name"],
+        },
+        "plurals": {
+            "rate": "limit",
+        },
+    }
+
+    serializers = {
+        'application/xml': wsgi.XMLDictSerializer(xmlns=xmlns,
+                                                  metadata=metadata)
+    }
+
+    return wsgi.Resource(controller, serializers=serializers)
+
+
 class Limit(object):
     """
     Stores information about a limit for HTTP requets.
@@ -197,7 +216,7 @@
 ]
 
 
-class RateLimitingMiddleware(wsgi.Middleware):
+class RateLimitingMiddleware(base_wsgi.Middleware):
     """
     Rate-limits requests passing through this middleware. All limit information
     is stored in memory for this implementation.
@@ -211,7 +230,7 @@
         @param application: WSGI application to wrap
         @param limits: List of dictionaries describing limits
         """
-        wsgi.Middleware.__init__(self, application)
+        base_wsgi.Middleware.__init__(self, application)
         self._limiter = Limiter(limits or DEFAULT_LIMITS)
 
     @wsgify(RequestClass=wsgi.Request)
 
=== modified file 'nova/api/openstack/server_metadata.py'
--- nova/api/openstack/server_metadata.py	2011-04-12 17:47:45 +0000
+++ nova/api/openstack/server_metadata.py	2011-05-26 21:32:29 +0000
@@ -19,12 +19,11 @@
 
 from nova import compute
 from nova import quota
-from nova import wsgi
-from nova.api.openstack import common
 from nova.api.openstack import faults
-
-
-class Controller(common.OpenstackController):
+from nova.api.openstack import wsgi
+
+
+class Controller(object):
     """ The server metadata API controller for the Openstack API """
 
     def __init__(self):
@@ -43,10 +42,9 @@
         context = req.environ['nova.context']
         return self._get_metadata(context, server_id)
 
-    def create(self, req, server_id):
+    def create(self, req, server_id, body):
         context = req.environ['nova.context']
-        data = self._deserialize(req.body, req.get_content_type())
-        metadata = data.get('metadata')
+        metadata = body.get('metadata')
         try:
             self.compute_api.update_or_create_instance_metadata(context,
                                                                 server_id,
@@ -55,9 +53,8 @@
             self._handle_quota_error(error)
         return req.body
 
-    def update(self, req, server_id, id):
+    def update(self, req, server_id, id, body):
         context = req.environ['nova.context']
-        body = self._deserialize(req.body, req.get_content_type())
         if not id in body:
             expl = _('Request body and URI mismatch')
             raise exc.HTTPBadRequest(explanation=expl)
@@ -92,3 +89,11 @@
         if error.code == "MetadataLimitExceeded":
             raise exc.HTTPBadRequest(explanation=error.message)
         raise error
+
+
+def create_resource():
+    serializers = {
+        'application/xml': wsgi.XMLDictSerializer(xmlns=wsgi.XMLNS_V11),
+    }
+
+    return wsgi.Resource(Controller(), serializers=serializers)
 
=== modified file 'nova/api/openstack/servers.py'
--- nova/api/openstack/servers.py	2011-05-25 17:55:51 +0000
+++ nova/api/openstack/servers.py	2011-05-26 21:32:29 +0000
@@ -31,6 +31,7 @@
 import nova.api.openstack.views.flavors
 import nova.api.openstack.views.images
 import nova.api.openstack.views.servers
+from nova.api.openstack import wsgi
 from nova.auth import manager as auth_manager
 from nova.compute import instance_types
 import nova.api.openstack
@@ -41,31 +42,12 @@
 FLAGS = flags.FLAGS
 
 
-class Controller(common.OpenstackController):
+class Controller(object):
     """ The Server API controller for the OpenStack API """
 
-    _serialization_metadata = {
-        "application/xml": {
-            "attributes": {
-                "server": ["id", "imageId", "name", "flavorId", "hostId",
-                           "status", "progress", "adminPass", "flavorRef",
-                           "imageRef"],
-                "link": ["rel", "type", "href"],
-            },
-            "dict_collections": {
-                "metadata": {"item_name": "meta", "item_key": "key"},
-            },
-            "list_collections": {
-                "public": {"item_name": "ip", "item_key": "addr"},
-                "private": {"item_name": "ip", "item_key": "addr"},
-            },
-        },
-    }
-
     def __init__(self):
         self.compute_api = compute.API()
         self._image_service = utils.import_object(FLAGS.image_service)
-        super(Controller, self).__init__()
 
     def index(self, req):
         """ Returns a list of server names and ids for a given user """
@@ -122,15 +104,14 @@
             return faults.Fault(exc.HTTPNotFound())
         return exc.HTTPAccepted()
 
-    def create(self, req):
+    def create(self, req, body):
         """ Creates a new server for a given user """
-        env = self._deserialize_create(req)
-        if not env:
+        if not body:
             return faults.Fault(exc.HTTPUnprocessableEntity())
 
         context = req.environ['nova.context']
 
-        password = self._get_server_admin_password(env['server'])
+        password = self._get_server_admin_password(body['server'])
 
         key_name = None
         key_data = None
@@ -140,7 +121,7 @@
             key_name = key_pair['name']
             key_data = key_pair['public_key']
 
-        requested_image_id = self._image_id_from_req_data(env)
+        requested_image_id = self._image_id_from_req_data(body)
         try:
             image_id = common.get_image_id_from_image_hash(self._image_service,
                 context, requested_image_id)
@@ -151,18 +132,18 @@
         kernel_id, ramdisk_id = self._get_kernel_ramdisk_from_image(
             req, image_id)
 
-        personality = env['server'].get('personality')
+        personality = body['server'].get('personality')
         injected_files = []
         if personality:
             injected_files = self._get_injected_files(personality)
 
-        flavor_id = self._flavor_id_from_req_data(env)
+        flavor_id = self._flavor_id_from_req_data(body)
 
-        if not 'name' in env['server']:
+        if not 'name' in body['server']:
             msg = _("Server name is not defined")
             return exc.HTTPBadRequest(msg)
 
-        name = env['server']['name']
+        name = body['server']['name']
         self._validate_server_name(name)
         name = name.strip()
 
@@ -179,7 +160,7 @@
                 display_description=name,
                 key_name=key_name,
                 key_data=key_data,
-                metadata=env['server'].get('metadata', {}),
+                metadata=body['server'].get('metadata', {}),
                 injected_files=injected_files,
                 admin_password=password)
         except quota.QuotaError as error:
@@ -193,18 +174,6 @@
         server['server']['adminPass'] = password
         return server
 
-    def _deserialize_create(self, request):
-        """
-        Deserialize a create request
-
-        Overrides normal behavior in the case of xml content
-        """
-        if request.content_type == "application/xml":
-            deserializer = ServerCreateRequestXMLDeserializer()
-            return deserializer.deserialize(request.body)
-        else:
-            return self._deserialize(request.body, request.get_content_type())
-
     def _get_injected_files(self, personality):
         """
         Create a list of injected files from the personality attribute
@@ -254,24 +223,23 @@
         return utils.generate_password(16)
 
     @scheduler_api.redirect_handler
-    def update(self, req, id):
+    def update(self, req, id, body):
         """ Updates the server name or password """
         if len(req.body) == 0:
             raise exc.HTTPUnprocessableEntity()
 
-        inst_dict = self._deserialize(req.body, req.get_content_type())
-        if not inst_dict:
+        if not body:
             return faults.Fault(exc.HTTPUnprocessableEntity())
 
         ctxt = req.environ['nova.context']
         update_dict = {}
 
-        if 'name' in inst_dict['server']:
-            name = inst_dict['server']['name']
+        if 'name' in body['server']:
+            name = body['server']['name']
             self._validate_server_name(name)
             update_dict['display_name'] = name.strip()
 
-        self._parse_update(ctxt, id, inst_dict, update_dict)
+        self._parse_update(ctxt, id, body, update_dict)
 
         try:
             self.compute_api.update(ctxt, id, **update_dict)
@@ -293,7 +261,7 @@
         pass
 
     @scheduler_api.redirect_handler
-    def action(self, req, id):
+    def action(self, req, id, body):
         """Multi-purpose method used to reboot, rebuild, or
         resize a server"""
 
@@ -306,10 +274,9 @@
             'rebuild': self._action_rebuild,
             }
 
-        input_dict = self._deserialize(req.body, req.get_content_type())
         for key in actions.keys():
-            if key in input_dict:
-                return actions[key](input_dict, req, id)
+            if key in body:
+                return actions[key](body, req, id)
         return faults.Fault(exc.HTTPNotImplemented())
 
     def _action_change_password(self, input_dict, req, id):
@@ -409,7 +376,7 @@
         return exc.HTTPAccepted()
 
     @scheduler_api.redirect_handler
-    def reset_network(self, req, id):
+    def reset_network(self, req, id, body):
         """
         Reset networking on an instance (admin only).
 
@@ -424,7 +391,7 @@
         return exc.HTTPAccepted()
 
     @scheduler_api.redirect_handler
-    def inject_network_info(self, req, id):
+    def inject_network_info(self, req, id, body):
         """
         Inject network info for an instance (admin only).
 
@@ -439,7 +406,7 @@
         return exc.HTTPAccepted()
 
     @scheduler_api.redirect_handler
-    def pause(self, req, id):
+    def pause(self, req, id, body):
         """ Permit Admins to Pause the server. """
         ctxt = req.environ['nova.context']
         try:
@@ -451,7 +418,7 @@
         return exc.HTTPAccepted()
 
     @scheduler_api.redirect_handler
-    def unpause(self, req, id):
+    def unpause(self, req, id, body):
         """ Permit Admins to Unpause the server. """
         ctxt = req.environ['nova.context']
         try:
@@ -463,7 +430,7 @@
         return exc.HTTPAccepted()
 
     @scheduler_api.redirect_handler
-    def suspend(self, req, id):
+    def suspend(self, req, id, body):
         """permit admins to suspend the server"""
         context = req.environ['nova.context']
         try:
@@ -475,7 +442,7 @@
         return exc.HTTPAccepted()
 
     @scheduler_api.redirect_handler
-    def resume(self, req, id):
+    def resume(self, req, id, body):
         """permit admins to resume the server from suspend"""
         context = req.environ['nova.context']
         try:
@@ -735,11 +702,8 @@
             raise exc.HTTPBadRequest(msg)
         return password
 
-    def get_default_xmlns(self, req):
-        return common.XML_NS_V11
-
-
-class ServerCreateRequestXMLDeserializer(object):
+
+class ServerXMLDeserializer(wsgi.XMLDeserializer):
     """
     Deserializer to handle xml-formatted server create requests.
 
@@ -747,7 +711,7 @@
     and personality attributes
     """
 
-    def deserialize(self, string):
+    def create(self, string):
         """Deserialize an xml-formatted server create request"""
         dom = minidom.parseString(string)
         server = self._extract_server(dom)
@@ -814,3 +778,43 @@
             if child.nodeType == child.TEXT_NODE:
                 return child.nodeValue
         return ""
+
+
+def create_resource(version='1.0'):
+    controller = {
+        '1.0': ControllerV10,
+        '1.1': ControllerV11,
+    }[version]()
+
+    metadata = {
+        "attributes": {
+            "server": ["id", "imageId", "name", "flavorId", "hostId",
+                       "status", "progress", "adminPass", "flavorRef",
+                       "imageRef"],
+            "link": ["rel", "type", "href"],
+        },
+        "dict_collections": {
+            "metadata": {"item_name": "meta", "item_key": "key"},
+        },
+        "list_collections": {
+            "public": {"item_name": "ip", "item_key": "addr"},
+            "private": {"item_name": "ip", "item_key": "addr"},
+        },
+    }
+
+    xmlns = {
+        '1.0': wsgi.XMLNS_V10,
+        '1.1': wsgi.XMLNS_V11,
+    }[version]
+
+    serializers = {
+        'application/xml': wsgi.XMLDictSerializer(metadata=metadata,
+                                                  xmlns=xmlns),
+    }
+
+    deserializers = {
+        'application/xml': ServerXMLDeserializer(),
+    }
+
+    return wsgi.Resource(controller, serializers=serializers,
+                         deserializers=deserializers)
 
=== modified file 'nova/api/openstack/shared_ip_groups.py'
--- nova/api/openstack/shared_ip_groups.py	2011-03-30 17:05:06 +0000
+++ nova/api/openstack/shared_ip_groups.py	2011-05-26 21:32:29 +0000
@@ -17,29 +17,13 @@
 
 from webob import exc
 
-from nova.api.openstack import common
 from nova.api.openstack import faults
-
-
-def _translate_keys(inst):
-    """ Coerces a shared IP group instance into proper dictionary format """
-    return dict(sharedIpGroup=inst)
-
-
-def _translate_detail_keys(inst):
-    """ Coerces a shared IP group instance into proper dictionary format with
-    correctly mapped attributes """
-    return dict(sharedIpGroups=inst)
-
-
-class Controller(common.OpenstackController):
+from nova.api.openstack import wsgi
+
+
+class Controller(object):
     """ The Shared IP Groups Controller for the Openstack API """
 
-    _serialization_metadata = {
-        'application/xml': {
-            'attributes': {
-                'sharedIpGroup': []}}}
-
     def index(self, req):
         """ Returns a list of Shared IP Groups for the user """
         raise faults.Fault(exc.HTTPNotImplemented())
@@ -48,7 +32,7 @@
         """ Shows in-depth information on a specific Shared IP Group """
         raise faults.Fault(exc.HTTPNotImplemented())
 
-    def update(self, req, id):
+    def update(self, req, id, body):
         """ You can't update a Shared IP Group """
         raise faults.Fault(exc.HTTPNotImplemented())
 
@@ -60,6 +44,10 @@
         """ Returns a complete list of Shared IP Groups """
         raise faults.Fault(exc.HTTPNotImplemented())
 
-    def create(self, req):
+    def create(self, req, body):
         """ Creates a new Shared IP group """
         raise faults.Fault(exc.HTTPNotImplemented())
+
+
+def create_resource():
+    return wsgi.Resource(Controller())
 
=== modified file 'nova/api/openstack/users.py'
--- nova/api/openstack/users.py	2011-04-27 21:03:05 +0000
+++ nova/api/openstack/users.py	2011-05-26 21:32:29 +0000
@@ -20,8 +20,10 @@
 from nova import log as logging
 from nova.api.openstack import common
 from nova.api.openstack import faults
+from nova.api.openstack import wsgi
 from nova.auth import manager
 
+
 FLAGS = flags.FLAGS
 LOG = logging.getLogger('nova.api.openstack')
 
@@ -34,12 +36,7 @@
                 admin=user.admin)
 
 
-class Controller(common.OpenstackController):
-
-    _serialization_metadata = {
-        'application/xml': {
-            "attributes": {
-                "user": ["id", "name", "access", "secret", "admin"]}}}
+class Controller(object):
 
     def __init__(self):
         self.manager = manager.AuthManager()
@@ -81,23 +78,35 @@
         self.manager.delete_user(id)
         return {}
 
-    def create(self, req):
+    def create(self, req, body):
         self._check_admin(req.environ['nova.context'])
-        env = self._deserialize(req.body, req.get_content_type())
-        is_admin = env['user'].get('admin') in ('T', 'True', True)
-        name = env['user'].get('name')
-        access = env['user'].get('access')
-        secret = env['user'].get('secret')
+        is_admin = body['user'].get('admin') in ('T', 'True', True)
+        name = body['user'].get('name')
+        access = body['user'].get('access')
+        secret = body['user'].get('secret')
         user = self.manager.create_user(name, access, secret, is_admin)
         return dict(user=_translate_keys(user))
 
-    def update(self, req, id):
+    def update(self, req, id, body):
         self._check_admin(req.environ['nova.context'])
-        env = self._deserialize(req.body, req.get_content_type())
-        is_admin = env['user'].get('admin')
+        is_admin = body['user'].get('admin')
         if is_admin is not None:
             is_admin = is_admin in ('T', 'True', True)
-        access = env['user'].get('access')
-        secret = env['user'].get('secret')
+        access = body['user'].get('access')
+        secret = body['user'].get('secret')
         self.manager.modify_user(id, access, secret, is_admin)
         return dict(user=_translate_keys(self.manager.get_user(id)))
+
+
+def create_resource():
+    metadata = {
+        "attributes": {
+            "user": ["id", "name", "access", "secret", "admin"],
+        },
+    }
+
+    serializers = {
+        'application/xml': wsgi.XMLDictSerializer(metadata=metadata),
+    }
+
+    return wsgi.Resource(Controller(), serializers=serializers)
 
=== modified file 'nova/api/openstack/versions.py'
--- nova/api/openstack/versions.py	2011-03-29 15:41:33 +0000
+++ nova/api/openstack/versions.py	2011-05-26 21:32:29 +0000
@@ -18,13 +18,26 @@
 import webob
 import webob.dec
 
-from nova import wsgi
 import nova.api.openstack.views.versions
-
-
-class Versions(wsgi.Application):
-    @webob.dec.wsgify(RequestClass=wsgi.Request)
-    def __call__(self, req):
+from nova.api.openstack import wsgi
+
+
+class Versions(wsgi.Resource):
+    def __init__(self):
+        metadata = {
+            "attributes": {
+                "version": ["status", "id"],
+                "link": ["rel", "href"],
+            }
+        }
+
+        serializers = {
+            'application/xml': wsgi.XMLDictSerializer(metadata=metadata),
+        }
+
+        super(Versions, self).__init__(None, serializers=serializers)
+
+    def dispatch(self, request, *args):
         """Respond to a request for all OpenStack API versions."""
         version_objs = [
             {
@@ -37,24 +50,6 @@
             },
         ]
 
-        builder = nova.api.openstack.views.versions.get_view_builder(req)
+        builder = nova.api.openstack.views.versions.get_view_builder(request)
         versions = [builder.build(version) for version in version_objs]
-        response = dict(versions=versions)
-
-        metadata = {
-            "application/xml": {
-                "attributes": {
-                    "version": ["status", "id"],
-                    "link": ["rel", "href"],
-                }
-            }
-        }
-
-        content_type = req.best_match_content_type()
-        body = wsgi.Serializer(metadata).serialize(response, content_type)
-
-        response = webob.Response()
-        response.content_type = content_type
-        response.body = body
-
-        return response
+        return dict(versions=versions)
 
=== added file 'nova/api/openstack/wsgi.py'
--- nova/api/openstack/wsgi.py	1970-01-01 00:00:00 +0000
+++ nova/api/openstack/wsgi.py	2011-05-26 21:32:29 +0000
@@ -0,0 +1,380 @@
+
+import json
+import webob
+from xml.dom import minidom
+
+from nova import exception
+from nova import log as logging
+from nova import utils
+from nova import wsgi
+
+
+XMLNS_V10 = 'http://docs.rackspacecloud.com/servers/api/v1.0'
+XMLNS_V11 = 'http://docs.openstack.org/compute/api/v1.1'
+
+LOG = logging.getLogger('nova.api.openstack.wsgi')
+
+
+class Request(webob.Request):
+    """Add some Openstack API-specific logic to the base webob.Request."""
+
+    def best_match_content_type(self):
+        """Determine the requested response content-type.
+
+        Based on the query extension then the Accept header.
+
+        """
+        supported = ('application/json', 'application/xml')
+
+        parts = self.path.rsplit('.', 1)
+        if len(parts) > 1:
+            ctype = 'application/{0}'.format(parts[1])
+            if ctype in supported:
+                return ctype
+
+        bm = self.accept.best_match(supported)
+
+        # default to application/json if we don't find a preference
+        return bm or 'application/json'
+
+    def get_content_type(self):
+        """Determine content type of the request body.
+
+        Does not do any body introspection, only checks header
+
+        """
+        if not "Content-Type" in self.headers:
+            raise exception.InvalidContentType(content_type=None)
+
+        allowed_types = ("application/xml", "application/json")
+        content_type = self.content_type
+
+        if content_type not in allowed_types:
+            raise exception.InvalidContentType(content_type=content_type)
+        else:
+            return content_type
+
+
+class TextDeserializer(object):
+    """Custom request body deserialization based on controller action name."""
+
+    def deserialize(self, datastring, action='default'):
+        """Find local deserialization method and parse request body."""
+        action_method = getattr(self, action, self.default)
+        return action_method(datastring)
+
+    def default(self, datastring):
+        """Default deserialization code should live here"""
+        raise NotImplementedError()
+
+
+class JSONDeserializer(TextDeserializer):
+
+    def default(self, datastring):
+        return utils.loads(datastring)
+
+
+class XMLDeserializer(TextDeserializer):
+
+    def __init__(self, metadata=None):
+        """
+        :param metadata: information needed to deserialize xml into
+                         a dictionary.
+        """
+        super(XMLDeserializer, self).__init__()
+        self.metadata = metadata or {}
+
+    def default(self, datastring):
+        plurals = set(self.metadata.get('plurals', {}))
+        node = minidom.parseString(datastring).childNodes[0]
+        return {node.nodeName: self._from_xml_node(node, plurals)}
+
+    def _from_xml_node(self, node, listnames):
+        """Convert a minidom node to a simple Python type.
+
+        :param listnames: list of XML node names whose subnodes should
+                          be considered list items.
+
+        """
+        if len(node.childNodes) == 1 and node.childNodes[0].nodeType == 3:
+            return node.childNodes[0].nodeValue
+        elif node.nodeName in listnames:
+            return [self._from_xml_node(n, listnames) for n in node.childNodes]
+        else:
+            result = dict()
+            for attr in node.attributes.keys():
+                result[attr] = node.attributes[attr].nodeValue
+            for child in node.childNodes:
+                if child.nodeType != node.TEXT_NODE:
+                    result[child.nodeName] = self._from_xml_node(child,
+                                                                 listnames)
+            return result
+
+
+class RequestDeserializer(object):
+    """Break up a Request object into more useful pieces."""
+
+    def __init__(self, deserializers=None):
+        """
+        :param deserializers: dictionary of content-type-specific deserializers
+
+        """
+        self.deserializers = {
+            'application/xml': XMLDeserializer(),
+            'application/json': JSONDeserializer(),
+        }
+
+        self.deserializers.update(deserializers or {})
+
+    def deserialize(self, request):
+        """Extract necessary pieces of the request.
+
+        :param request: Request object
+        :returns tuple of expected controller action name, dictionary of
+                 keyword arguments to pass to the controller, the expected
+                 content type of the response
+
+        """
+        action_args = self.get_action_args(request.environ)
+        action = action_args.pop('action', None)
+
+        if request.method.lower() in ('post', 'put'):
+            if len(request.body) == 0:
+                action_args['body'] = None
+            else:
+                content_type = request.get_content_type()
+                deserializer = self.get_deserializer(content_type)
+
+                try:
+                    body = deserializer.deserialize(request.body, action)
+                    action_args['body'] = body
+                except exception.InvalidContentType:
+                    action_args['body'] = None
+
+        accept = self.get_expected_content_type(request)
+
+        return (action, action_args, accept)
+
+    def get_deserializer(self, content_type):
+        try:
+            return self.deserializers[content_type]
+        except (KeyError, TypeError):
+            raise exception.InvalidContentType(content_type=content_type)
+
+    def get_expected_content_type(self, request):
+        return request.best_match_content_type()
+
+    def get_action_args(self, request_environment):
+        """Parse dictionary created by routes library."""
+        try:
+            args = request_environment['wsgiorg.routing_args'][1].copy()
+        except Exception:
+            return {}
+
+        try:
+            del args['controller']
+        except KeyError:
+            pass
+
+        try:
+            del args['format']
+        except KeyError:
+            pass
+
+        return args
+
+
+class DictSerializer(object):
+    """Custom response body serialization based on controller action name."""
+
+    def serialize(self, data, action='default'):
+        """Find local serialization method and encode response body."""
+        action_method = getattr(self, action, self.default)
+        return action_method(data)
+
+    def default(self, data):
+        """Default serialization code should live here"""
+        raise NotImplementedError()
+
+
+class JSONDictSerializer(DictSerializer):
+
+    def default(self, data):
+        return utils.dumps(data)
+
+
+class XMLDictSerializer(DictSerializer):
+
+    def __init__(self, metadata=None, xmlns=None):
+        """
+        :param metadata: information needed to deserialize xml into
+                         a dictionary.
+        :param xmlns: XML namespace to include with serialized xml
+        """
+        super(XMLDictSerializer, self).__init__()
+        self.metadata = metadata or {}
+        self.xmlns = xmlns
+
+    def default(self, data):
+        # We expect data to contain a single key which is the XML root.
+        root_key = data.keys()[0]
+        doc = minidom.Document()
+        node = self._to_xml_node(doc, self.metadata, root_key, data[root_key])
+
+        xmlns = node.getAttribute('xmlns')
+        if not xmlns and self.xmlns:
+            node.setAttribute('xmlns', self.xmlns)
+
+        return node.toprettyxml(indent='    ')
+
+    def _to_xml_node(self, doc, metadata, nodename, data):
+        """Recursive method to convert data members to XML nodes."""
+        result = doc.createElement(nodename)
+
+        # Set the xml namespace if one is specified
+        # TODO(justinsb): We could also use prefixes on the keys
+        xmlns = metadata.get('xmlns', None)
+        if xmlns:
+            result.setAttribute('xmlns', xmlns)
+
+        #TODO(bcwaldon): accomplish this without a type-check
+        if type(data) is list:
+            collections = metadata.get('list_collections', {})
+            if nodename in collections:
+                metadata = collections[nodename]
+                for item in data:
+                    node = doc.createElement(metadata['item_name'])
+                    node.setAttribute(metadata['item_key'], str(item))
+                    result.appendChild(node)
+                return result
+            singular = metadata.get('plurals', {}).get(nodename, None)
+            if singular is None:
+                if nodename.endswith('s'):
+                    singular = nodename[:-1]
+                else:
+                    singular = 'item'
+            for item in data:
+                node = self._to_xml_node(doc, metadata, singular, item)
+                result.appendChild(node)
+        #TODO(bcwaldon): accomplish this without a type-check
+        elif type(data) is dict:
+            collections = metadata.get('dict_collections', {})
+            if nodename in collections:
+                metadata = collections[nodename]
+                for k, v in data.items():
+                    node = doc.createElement(metadata['item_name'])
+                    node.setAttribute(metadata['item_key'], str(k))
+                    text = doc.createTextNode(str(v))
+                    node.appendChild(text)
+                    result.appendChild(node)
+                return result
+            attrs = metadata.get('attributes', {}).get(nodename, {})
+            for k, v in data.items():
+                if k in attrs:
+                    result.setAttribute(k, str(v))
+                else:
+                    node = self._to_xml_node(doc, metadata, k, v)
+                    result.appendChild(node)
+        else:
+            # Type is atom
+            node = doc.createTextNode(str(data))
+            result.appendChild(node)
+        return result
+
+
+class ResponseSerializer(object):
+    """Encode the necessary pieces into a response object"""
+
+    def __init__(self, serializers=None):
+        """
+        :param serializers: dictionary of content-type-specific serializers
+
+        """
+        self.serializers = {
+            'application/xml': XMLDictSerializer(),
+            'application/json': JSONDictSerializer(),
+        }
+        self.serializers.update(serializers or {})
+
+    def serialize(self, response_data, content_type):
+        """Serialize a dict into a string and wrap in a wsgi.Request object.
+
+        :param response_data: dict produced by the Controller
+        :param content_type: expected mimetype of serialized response body
+
+        """
+        response = webob.Response()
+        response.headers['Content-Type'] = content_type
+
+        serializer = self.get_serializer(content_type)
+        response.body = serializer.serialize(response_data)
+
+        return response
+
+    def get_serializer(self, content_type):
+        try:
+            return self.serializers[content_type]
+        except (KeyError, TypeError):
+            raise exception.InvalidContentType(content_type=content_type)
+
+
+class Resource(wsgi.Application):
+    """WSGI app that handles (de)serialization and controller dispatch.
+
+    WSGI app that reads routing information supplied by RoutesMiddleware
+    and calls the requested action method upon its controller.  All
+    controller action methods must accept a 'req' argument, which is the
+    incoming wsgi.Request. If the operation is a PUT or POST, the controller
+    method must also accept a 'body' argument (the deserialized request body).
+    They may raise a webob.exc exception or return a dict, which will be
+    serialized by requested content type.
+
+    """
+    def __init__(self, controller, serializers=None, deserializers=None):
+        """
+        :param controller: object that implement methods created by routes lib
+        :param serializers: dict of content-type specific text serializers
+        :param deserializers: dict of content-type specific text deserializers
+
+        """
+        self.controller = controller
+        self.serializer = ResponseSerializer(serializers)
+        self.deserializer = RequestDeserializer(deserializers)
+
+    @webob.dec.wsgify(RequestClass=Request)
+    def __call__(self, request):
+        """WSGI method that controls (de)serialization and method dispatch."""
+
+        LOG.debug("%(method)s %(url)s" % {"method": request.method,
+                                          "url": request.url})
+
+        try:
+            action, action_args, accept = self.deserializer.deserialize(
+                                                                      request)
+        except exception.InvalidContentType:
+            return webob.exc.HTTPBadRequest(_("Unsupported Content-Type"))
+
+        action_result = self.dispatch(request, action, action_args)
+
+        #TODO(bcwaldon): find a more elegant way to pass through non-dict types
+        if type(action_result) is dict:
+            response = self.serializer.serialize(action_result, accept)
+        else:
+            response = action_result
+
+        try:
+            msg_dict = dict(url=request.url, status=response.status_int)
+            msg = _("%(url)s returned with HTTP %(status)d") % msg_dict
+        except AttributeError:
+            msg_dict = dict(url=request.url)
+            msg = _("%(url)s returned a fault")
+
+        LOG.debug(msg)
+
+        return response
+
+    def dispatch(self, request, action, action_args):
+        """Find action-spefic method on controller and call it."""
+
+        controller_method = getattr(self.controller, action)
+        return controller_method(req=request, **action_args)
 
=== modified file 'nova/api/openstack/zones.py'
--- nova/api/openstack/zones.py	2011-05-18 20:14:24 +0000
+++ nova/api/openstack/zones.py	2011-05-26 21:32:29 +0000
@@ -22,6 +22,7 @@
 from nova import flags
 from nova import log as logging
 from nova.api.openstack import common
+from nova.api.openstack import wsgi
 from nova.scheduler import api
 
 
@@ -52,12 +53,7 @@
                     'deleted', 'deleted_at', 'updated_at'))
 
 
-class Controller(common.OpenstackController):
-
-    _serialization_metadata = {
-        'application/xml': {
-            "attributes": {
-                "zone": ["id", "api_url", "name", "capabilities"]}}}
+class Controller(object):
 
     def index(self, req):
         """Return all zones in brief"""
@@ -96,17 +92,15 @@
         api.zone_delete(req.environ['nova.context'], zone_id)
         return {}
 
-    def create(self, req):
+    def create(self, req, body):
         context = req.environ['nova.context']
-        env = self._deserialize(req.body, req.get_content_type())
-        zone = api.zone_create(context, env["zone"])
+        zone = api.zone_create(context, body["zone"])
         return dict(zone=_scrub_zone(zone))
 
-    def update(self, req, id):
+    def update(self, req, id, body):
         context = req.environ['nova.context']
-        env = self._deserialize(req.body, req.get_content_type())
         zone_id = int(id)
-        zone = api.zone_update(context, zone_id, env["zone"])
+        zone = api.zone_update(context, zone_id, body["zone"])
         return dict(zone=_scrub_zone(zone))
 
     def select(self, req):
@@ -140,3 +134,18 @@
             cooked.append(dict(weight=entry['weight'],
                 blob=cipher_text))
         return cooked
+
+
+def create_resource():
+    metadata = {
+        "attributes": {
+            "zone": ["id", "api_url", "name", "capabilities"],
+        },
+    }
+
+    serializers = {
+        'application/xml': wsgi.XMLDictSerializer(xmlns=wsgi.XMLNS_V10,
+                                                  metadata=metadata),
+    }
+
+    return wsgi.Resource(Controller(), serializers=serializers)
 
=== modified file 'nova/objectstore/s3server.py'
--- nova/objectstore/s3server.py	2011-03-24 23:38:31 +0000
+++ nova/objectstore/s3server.py	2011-05-26 21:32:29 +0000
@@ -81,7 +81,7 @@
         super(S3Application, self).__init__(mapper)
 
 
-class BaseRequestHandler(wsgi.Controller):
+class BaseRequestHandler(object):
     """Base class emulating Tornado's web framework pattern in WSGI.
 
     This is a direct port of Tornado's implementation, so some key decisions
 
=== modified file 'nova/tests/api/openstack/extensions/foxinsocks.py'
--- nova/tests/api/openstack/extensions/foxinsocks.py	2011-05-12 18:45:39 +0000
+++ nova/tests/api/openstack/extensions/foxinsocks.py	2011-05-26 21:32:29 +0000
@@ -17,12 +17,10 @@
 
 import json
 
-from nova import wsgi
-
 from nova.api.openstack import extensions
 
 
-class FoxInSocksController(wsgi.Controller):
+class FoxInSocksController(object):
 
     def index(self, req):
         return "Try to say this Mr. Knox, sir..."
 
=== modified file 'nova/tests/api/openstack/test_extensions.py'
--- nova/tests/api/openstack/test_extensions.py	2011-05-12 18:37:15 +0000
+++ nova/tests/api/openstack/test_extensions.py	2011-05-26 21:32:29 +0000
@@ -26,15 +26,15 @@
 from nova.api import openstack
 from nova.api.openstack import extensions
 from nova.api.openstack import flavors
+from nova.api.openstack import wsgi
 from nova.tests.api.openstack import fakes
-import nova.wsgi
 
 FLAGS = flags.FLAGS
 
 response_body = "Try to say this Mr. Knox, sir..."
 
 
-class StubController(nova.wsgi.Controller):
+class StubController(object):
 
     def __init__(self, body):
         self.body = body
 
=== modified file 'nova/tests/api/openstack/test_limits.py'
--- nova/tests/api/openstack/test_limits.py	2011-05-25 20:58:40 +0000
+++ nova/tests/api/openstack/test_limits.py	2011-05-26 21:32:29 +0000
@@ -73,7 +73,7 @@
     def setUp(self):
         """Run before each test."""
         BaseLimitTestSuite.setUp(self)
-        self.controller = limits.LimitsControllerV10()
+        self.controller = limits.create_resource('1.0')
 
     def _get_index_request(self, accept_header="application/json"):
         """Helper to set routing arguments."""
@@ -209,7 +209,7 @@
     def setUp(self):
         """Run before each test."""
         BaseLimitTestSuite.setUp(self)
-        self.controller = limits.LimitsControllerV11()
+        self.controller = limits.create_resource('1.1')
 
     def _get_index_request(self, accept_header="application/json"):
         """Helper to set routing arguments."""
 
=== modified file 'nova/tests/api/openstack/test_servers.py'
--- nova/tests/api/openstack/test_servers.py	2011-05-25 20:10:25 +0000
+++ nova/tests/api/openstack/test_servers.py	2011-05-26 21:32:29 +0000
@@ -217,7 +217,6 @@
             },
         ]
 
-        print res_dict['server']
         self.assertEqual(res_dict['server']['links'], expected_links)
 
     def test_get_server_by_id_with_addresses_xml(self):
@@ -844,7 +843,6 @@
         req = webob.Request.blank('/v1.0/servers/detail')
         req.headers['Accept'] = 'application/xml'
         res = req.get_response(fakes.wsgi_app())
-        print res.body
         dom = minidom.parseString(res.body)
         for i, server in enumerate(dom.getElementsByTagName('server')):
             self.assertEqual(server.getAttribute('id'), str(i))
@@ -1008,6 +1006,14 @@
         res = req.get_response(fakes.wsgi_app())
         self.assertEqual(res.status_int, 501)
 
+    def test_server_change_password_xml(self):
+        req = webob.Request.blank('/v1.0/servers/1/action')
+        req.method = 'POST'
+        req.content_type = 'application/xml'
+        req.body = '<changePassword adminPass="1234pass">'
+#        res = req.get_response(fakes.wsgi_app())
+#        self.assertEqual(res.status_int, 501)
+
     def test_server_change_password_v1_1(self):
         mock_method = MockSetAdminPassword()
         self.stubs.Set(nova.compute.api.API, 'set_admin_password', mock_method)
@@ -1380,13 +1386,13 @@
 class TestServerCreateRequestXMLDeserializer(unittest.TestCase):
 
     def setUp(self):
-        self.deserializer = servers.ServerCreateRequestXMLDeserializer()
+        self.deserializer = servers.ServerXMLDeserializer()
 
     def test_minimal_request(self):
         serial_request = """
 <server xmlns="http://docs.rackspacecloud.com/servers/api/v1.0"
  name="new-server-test" imageId="1" flavorId="1"/>"""
-        request = self.deserializer.deserialize(serial_request)
+        request = self.deserializer.deserialize(serial_request, 'create')
         expected = {"server": {
                 "name": "new-server-test",
                 "imageId": "1",
@@ -1400,7 +1406,7 @@
  name="new-server-test" imageId="1" flavorId="1">
     <metadata/>
 </server>"""
-        request = self.deserializer.deserialize(serial_request)
+        request = self.deserializer.deserialize(serial_request, 'create')
         expected = {"server": {
                 "name": "new-server-test",
                 "imageId": "1",
@@ -1415,7 +1421,7 @@
  name="new-server-test" imageId="1" flavorId="1">
     <personality/>
 </server>"""
-        request = self.deserializer.deserialize(serial_request)
+        request = self.deserializer.deserialize(serial_request, 'create')
         expected = {"server": {
                 "name": "new-server-test",
                 "imageId": "1",
@@ -1431,7 +1437,7 @@
     <metadata/>
     <personality/>
 </server>"""
-        request = self.deserializer.deserialize(serial_request)
+        request = self.deserializer.deserialize(serial_request, 'create')
         expected = {"server": {
                 "name": "new-server-test",
                 "imageId": "1",
@@ -1448,7 +1454,7 @@
     <personality/>
     <metadata/>
 </server>"""
-        request = self.deserializer.deserialize(serial_request)
+        request = self.deserializer.deserialize(serial_request, 'create')
         expected = {"server": {
                 "name": "new-server-test",
                 "imageId": "1",
@@ -1466,7 +1472,7 @@
         <file path="/etc/conf">aabbccdd</file>
     </personality>
 </server>"""
-        request = self.deserializer.deserialize(serial_request)
+        request = self.deserializer.deserialize(serial_request, 'create')
         expected = [{"path": "/etc/conf", "contents": "aabbccdd"}]
         self.assertEquals(request["server"]["personality"], expected)
 
@@ -1476,7 +1482,7 @@
  name="new-server-test" imageId="1" flavorId="1">
 <personality><file path="/etc/conf">aabbccdd</file>
 <file path="/etc/sudoers">abcd</file></personality></server>"""
-        request = self.deserializer.deserialize(serial_request)
+        request = self.deserializer.deserialize(serial_request, 'create')
         expected = [{"path": "/etc/conf", "contents": "aabbccdd"},
                     {"path": "/etc/sudoers", "contents": "abcd"}]
         self.assertEquals(request["server"]["personality"], expected)
@@ -1492,7 +1498,7 @@
         <file path="/etc/ignoreme">anything</file>
     </personality>
 </server>"""
-        request = self.deserializer.deserialize(serial_request)
+        request = self.deserializer.deserialize(serial_request, 'create')
         expected = [{"path": "/etc/conf", "contents": "aabbccdd"}]
         self.assertEquals(request["server"]["personality"], expected)
 
@@ -1501,7 +1507,7 @@
 <server xmlns="http://docs.rackspacecloud.com/servers/api/v1.0"
  name="new-server-test" imageId="1" flavorId="1">
 <personality><file>aabbccdd</file></personality></server>"""
-        request = self.deserializer.deserialize(serial_request)
+        request = self.deserializer.deserialize(serial_request, 'create')
         expected = [{"contents": "aabbccdd"}]
         self.assertEquals(request["server"]["personality"], expected)
 
@@ -1510,7 +1516,7 @@
 <server xmlns="http://docs.rackspacecloud.com/servers/api/v1.0"
  name="new-server-test" imageId="1" flavorId="1">
 <personality><file path="/etc/conf"></file></personality></server>"""
-        request = self.deserializer.deserialize(serial_request)
+        request = self.deserializer.deserialize(serial_request, 'create')
         expected = [{"path": "/etc/conf", "contents": ""}]
         self.assertEquals(request["server"]["personality"], expected)
 
@@ -1519,7 +1525,7 @@
 <server xmlns="http://docs.rackspacecloud.com/servers/api/v1.0"
  name="new-server-test" imageId="1" flavorId="1">
 <personality><file path="/etc/conf"/></personality></server>"""
-        request = self.deserializer.deserialize(serial_request)
+        request = self.deserializer.deserialize(serial_request, 'create')
         expected = [{"path": "/etc/conf", "contents": ""}]
         self.assertEquals(request["server"]["personality"], expected)
 
@@ -1531,7 +1537,7 @@
         <meta key="alpha">beta</meta>
     </metadata>
 </server>"""
-        request = self.deserializer.deserialize(serial_request)
+        request = self.deserializer.deserialize(serial_request, 'create')
         expected = {"alpha": "beta"}
         self.assertEquals(request["server"]["metadata"], expected)
 
@@ -1544,7 +1550,7 @@
         <meta key="foo">bar</meta>
     </metadata>
 </server>"""
-        request = self.deserializer.deserialize(serial_request)
+        request = self.deserializer.deserialize(serial_request, 'create')
         expected = {"alpha": "beta", "foo": "bar"}
         self.assertEquals(request["server"]["metadata"], expected)
 
@@ -1556,7 +1562,7 @@
         <meta key="alpha"></meta>
     </metadata>
 </server>"""
-        request = self.deserializer.deserialize(serial_request)
+        request = self.deserializer.deserialize(serial_request, 'create')
         expected = {"alpha": ""}
         self.assertEquals(request["server"]["metadata"], expected)
 
@@ -1569,7 +1575,7 @@
         <meta key="delta"/>
     </metadata>
 </server>"""
-        request = self.deserializer.deserialize(serial_request)
+        request = self.deserializer.deserialize(serial_request, 'create')
         expected = {"alpha": "", "delta": ""}
         self.assertEquals(request["server"]["metadata"], expected)
 
@@ -1581,7 +1587,7 @@
         <meta>beta</meta>
     </metadata>
 </server>"""
-        request = self.deserializer.deserialize(serial_request)
+        request = self.deserializer.deserialize(serial_request, 'create')
         expected = {"": "beta"}
         self.assertEquals(request["server"]["metadata"], expected)
 
@@ -1594,7 +1600,7 @@
         <meta>gamma</meta>
     </metadata>
 </server>"""
-        request = self.deserializer.deserialize(serial_request)
+        request = self.deserializer.deserialize(serial_request, 'create')
         expected = {"": "gamma"}
         self.assertEquals(request["server"]["metadata"], expected)
 
@@ -1607,7 +1613,7 @@
         <meta key="foo">baz</meta>
     </metadata>
 </server>"""
-        request = self.deserializer.deserialize(serial_request)
+        request = self.deserializer.deserialize(serial_request, 'create')
         expected = {"foo": "baz"}
         self.assertEquals(request["server"]["metadata"], expected)
 
@@ -1654,7 +1660,7 @@
                 },
             ],
         }}
-        request = self.deserializer.deserialize(serial_request)
+        request = self.deserializer.deserialize(serial_request, 'create')
         self.assertEqual(request, expected)
 
     def test_request_xmlser_with_flavor_image_ref(self):
@@ -1664,7 +1670,7 @@
                     imageRef="http://localhost:8774/v1.1/images/1"
                     flavorRef="http://localhost:8774/v1.1/flavors/1">
                 </server>"""
-        request = self.deserializer.deserialize(serial_request)
+        request = self.deserializer.deserialize(serial_request, 'create')
         self.assertEquals(request["server"]["flavorRef"],
                           "http://localhost:8774/v1.1/flavors/1")
         self.assertEquals(request["server"]["imageRef"],
 
=== added file 'nova/tests/api/openstack/test_wsgi.py'
--- nova/tests/api/openstack/test_wsgi.py	1970-01-01 00:00:00 +0000
+++ nova/tests/api/openstack/test_wsgi.py	2011-05-26 21:32:29 +0000
@@ -0,0 +1,293 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+import json
+import webob
+
+from nova import exception
+from nova import test
+from nova.api.openstack import wsgi
+
+
+class RequestTest(test.TestCase):
+    def test_content_type_missing(self):
+        request = wsgi.Request.blank('/tests/123')
+        request.body = "<body />"
+        self.assertRaises(exception.InvalidContentType,
+                          request.get_content_type)
+
+    def test_content_type_unsupported(self):
+        request = wsgi.Request.blank('/tests/123')
+        request.headers["Content-Type"] = "text/html"
+        request.body = "asdf<br />"
+        self.assertRaises(exception.InvalidContentType,
+                          request.get_content_type)
+
+    def test_content_type_with_charset(self):
+        request = wsgi.Request.blank('/tests/123')
+        request.headers["Content-Type"] = "application/json; charset=UTF-8"
+        result = request.get_content_type()
+        self.assertEqual(result, "application/json")
+
+    def test_content_type_from_accept_xml(self):
+        request = wsgi.Request.blank('/tests/123')
+        request.headers["Accept"] = "application/xml"
+        result = request.best_match_content_type()
+        self.assertEqual(result, "application/xml")
+
+        request = wsgi.Request.blank('/tests/123')
+        request.headers["Accept"] = "application/json"
+        result = request.best_match_content_type()
+        self.assertEqual(result, "application/json")
+
+        request = wsgi.Request.blank('/tests/123')
+        request.headers["Accept"] = "application/xml, application/json"
+        result = request.best_match_content_type()
+        self.assertEqual(result, "application/json")
+
+        request = wsgi.Request.blank('/tests/123')
+        request.headers["Accept"] = \
+            "application/json; q=0.3, application/xml; q=0.9"
+        result = request.best_match_content_type()
+        self.assertEqual(result, "application/xml")
+
+    def test_content_type_from_query_extension(self):
+        request = wsgi.Request.blank('/tests/123.xml')
+        result = request.best_match_content_type()
+        self.assertEqual(result, "application/xml")
+
+        request = wsgi.Request.blank('/tests/123.json')
+        result = request.best_match_content_type()
+        self.assertEqual(result, "application/json")
+
+        request = wsgi.Request.blank('/tests/123.invalid')
+        result = request.best_match_content_type()
+        self.assertEqual(result, "application/json")
+
+    def test_content_type_accept_and_query_extension(self):
+        request = wsgi.Request.blank('/tests/123.xml')
+        request.headers["Accept"] = "application/json"
+        result = request.best_match_content_type()
+        self.assertEqual(result, "application/xml")
+
+    def test_content_type_accept_default(self):
+        request = wsgi.Request.blank('/tests/123.unsupported')
+        request.headers["Accept"] = "application/unsupported1"
+        result = request.best_match_content_type()
+        self.assertEqual(result, "application/json")
+
+
+class DictSerializerTest(test.TestCase):
+    def test_dispatch(self):
+        serializer = wsgi.DictSerializer()
+        serializer.create = lambda x: 'pants'
+        serializer.default = lambda x: 'trousers'
+        self.assertEqual(serializer.serialize({}, 'create'), 'pants')
+
+    def test_dispatch_default(self):
+        serializer = wsgi.DictSerializer()
+        serializer.create = lambda x: 'pants'
+        serializer.default = lambda x: 'trousers'
+        self.assertEqual(serializer.serialize({}, 'update'), 'trousers')
+
+
+class XMLDictSerializerTest(test.TestCase):
+    def test_xml(self):
+        input_dict = dict(servers=dict(a=(2, 3)))
+        expected_xml = '<serversxmlns="asdf"><a>(2,3)</a></servers>'
+        serializer = wsgi.XMLDictSerializer(xmlns="asdf")
+        result = serializer.serialize(input_dict)
+        result = result.replace('\n', '').replace(' ', '')
+        self.assertEqual(result, expected_xml)
+
+
+class JSONDictSerializerTest(test.TestCase):
+    def test_json(self):
+        input_dict = dict(servers=dict(a=(2, 3)))
+        expected_json = '{"servers":{"a":[2,3]}}'
+        serializer = wsgi.JSONDictSerializer()
+        result = serializer.serialize(input_dict)
+        result = result.replace('\n', '').replace(' ', '')
+        self.assertEqual(result, expected_json)
+
+
+class TextDeserializerTest(test.TestCase):
+    def test_dispatch(self):
+        deserializer = wsgi.TextDeserializer()
+        deserializer.create = lambda x: 'pants'
+        deserializer.default = lambda x: 'trousers'
+        self.assertEqual(deserializer.deserialize({}, 'create'), 'pants')
+
+    def test_dispatch_default(self):
+        deserializer = wsgi.TextDeserializer()
+        deserializer.create = lambda x: 'pants'
+        deserializer.default = lambda x: 'trousers'
+        self.assertEqual(deserializer.deserialize({}, 'update'), 'trousers')
+
+
+class JSONDeserializerTest(test.TestCase):
+    def test_json(self):
+        data = """{"a": {
+                "a1": "1",
+                "a2": "2",
+                "bs": ["1", "2", "3", {"c": {"c1": "1"}}],
+                "d": {"e": "1"},
+                "f": "1"}}"""
+        as_dict = dict(a={
+                'a1': '1',
+                'a2': '2',
+                'bs': ['1', '2', '3', {'c': dict(c1='1')}],
+                'd': {'e': '1'},
+                'f': '1'})
+        deserializer = wsgi.JSONDeserializer()
+        self.assertEqual(deserializer.deserialize(data), as_dict)
+
+
+class XMLDeserializerTest(test.TestCase):
+    def test_xml(self):
+        xml = """
+            <a a1="1" a2="2">
+              <bs><b>1</b><b>2</b><b>3</b><b><c c1="1"/></b></bs>
+              <d><e>1</e></d>
+              <f>1</f>
+            </a>
+            """.strip()
+        as_dict = dict(a={
+                'a1': '1',
+                'a2': '2',
+                'bs': ['1', '2', '3', {'c': dict(c1='1')}],
+                'd': {'e': '1'},
+                'f': '1'})
+        metadata = {'plurals': {'bs': 'b', 'ts': 't'}}
+        deserializer = wsgi.XMLDeserializer(metadata=metadata)
+        self.assertEqual(deserializer.deserialize(xml), as_dict)
+
+    def test_xml_empty(self):
+        xml = """<a></a>"""
+        as_dict = {"a": {}}
+        deserializer = wsgi.XMLDeserializer()
+        self.assertEqual(deserializer.deserialize(xml), as_dict)
+
+
+class ResponseSerializerTest(test.TestCase):
+    def setUp(self):
+        class JSONSerializer(object):
+            def serialize(self, data):
+                return 'pew_json'
+
+        class XMLSerializer(object):
+            def serialize(self, data):
+                return 'pew_xml'
+
+        self.serializers = {
+            'application/json': JSONSerializer(),
+            'application/XML': XMLSerializer(),
+        }
+
+        self.serializer = wsgi.ResponseSerializer(serializers=self.serializers)
+
+    def tearDown(self):
+        pass
+
+    def test_get_serializer(self):
+        self.assertEqual(self.serializer.get_serializer('application/json'),
+                         self.serializers['application/json'])
+
+    def test_get_serializer_unknown_content_type(self):
+        self.assertRaises(exception.InvalidContentType,
+                          self.serializer.get_serializer,
+                          'application/unknown')
+
+    def test_serialize_response(self):
+        response = self.serializer.serialize({}, 'application/json')
+        self.assertEqual(response.headers['Content-Type'], 'application/json')
+        self.assertEqual(response.body, 'pew_json')
+
+    def test_serialize_response_dict_to_unknown_content_type(self):
+        self.assertRaises(exception.InvalidContentType,
+                          self.serializer.serialize,
+                          {}, 'application/unknown')
+
+
+class RequestDeserializerTest(test.TestCase):
+    def setUp(self):
+        class JSONDeserializer(object):
+            def deserialize(self, data):
+                return 'pew_json'
+
+        class XMLDeserializer(object):
+            def deserialize(self, data):
+                return 'pew_xml'
+
+        self.deserializers = {
+            'application/json': JSONDeserializer(),
+            'application/XML': XMLDeserializer(),
+        }
+
+        self.deserializer = wsgi.RequestDeserializer(
+                                            deserializers=self.deserializers)
+
+    def tearDown(self):
+        pass
+
+    def test_get_deserializer(self):
+        expected = self.deserializer.get_deserializer('application/json')
+        self.assertEqual(expected, self.deserializers['application/json'])
+
+    def test_get_deserializer_unknown_content_type(self):
+        self.assertRaises(exception.InvalidContentType,
+                          self.deserializer.get_deserializer,
+                          'application/unknown')
+
+    def test_get_expected_content_type(self):
+        request = wsgi.Request.blank('/')
+        request.headers['Accept'] = 'application/json'
+        self.assertEqual(self.deserializer.get_expected_content_type(request),
+                         'application/json')
+
+    def test_get_action_args(self):
+        env = {
+            'wsgiorg.routing_args': [None, {
+                'controller': None,
+                'format': None,
+                'action': 'update',
+                'id': 12,
+            }],
+        }
+
+        expected = {'action': 'update', 'id': 12}
+
+        self.assertEqual(self.deserializer.get_action_args(env), expected)
+
+    def test_deserialize(self):
+        def fake_get_routing_args(request):
+            return {'action': 'create'}
+        self.deserializer.get_action_args = fake_get_routing_args
+
+        request = wsgi.Request.blank('/')
+        request.headers['Accept'] = 'application/xml'
+
+        deserialized = self.deserializer.deserialize(request)
+        expected = ('create', {}, 'application/xml')
+
+        self.assertEqual(expected, deserialized)
+
+
+class ResourceTest(test.TestCase):
+    def test_dispatch(self):
+        class Controller(object):
+            def index(self, req, pants=None):
+                return pants
+
+        resource = wsgi.Resource(Controller())
+        actual = resource.dispatch(None, 'index', {'pants': 'off'})
+        expected = 'off'
+        self.assertEqual(actual, expected)
+
+    def test_dispatch_unknown_controller_action(self):
+        class Controller(object):
+            def index(self, req, pants=None):
+                return pants
+
+        resource = wsgi.Resource(Controller())
+        self.assertRaises(AttributeError, resource.dispatch,
+                          None, 'create', {})
 
=== modified file 'nova/tests/api/test_wsgi.py'
--- nova/tests/api/test_wsgi.py	2011-04-20 18:01:14 +0000
+++ nova/tests/api/test_wsgi.py	2011-05-26 21:32:29 +0000
@@ -67,192 +67,3 @@
         self.assertEqual(result.body, "Router result")
         result = webob.Request.blank('/bad').get_response(Router())
         self.assertNotEqual(result.body, "Router result")
-
-
-class ControllerTest(test.TestCase):
-
-    class TestRouter(wsgi.Router):
-
-        class TestController(wsgi.Controller):
-
-            _serialization_metadata = {
-                'application/xml': {
-                    "attributes": {
-                        "test": ["id"]}}}
-
-            def show(self, req, id):  # pylint: disable=W0622,C0103
-                return {"test": {"id": id}}
-
-        def __init__(self):
-            mapper = routes.Mapper()
-            mapper.resource("test", "tests", controller=self.TestController())
-            wsgi.Router.__init__(self, mapper)
-
-    def test_show(self):
-        request = wsgi.Request.blank('/tests/123')
-        result = request.get_response(self.TestRouter())
-        self.assertEqual(json.loads(result.body), {"test": {"id": "123"}})
-
-    def test_response_content_type_from_accept_xml(self):
-        request = webob.Request.blank('/tests/123')
-        request.headers["Accept"] = "application/xml"
-        result = request.get_response(self.TestRouter())
-        self.assertEqual(result.headers["Content-Type"], "application/xml")
-
-    def test_response_content_type_from_accept_json(self):
-        request = wsgi.Request.blank('/tests/123')
-        request.headers["Accept"] = "application/json"
-        result = request.get_response(self.TestRouter())
-        self.assertEqual(result.headers["Content-Type"], "application/json")
-
-    def test_response_content_type_from_query_extension_xml(self):
-        request = wsgi.Request.blank('/tests/123.xml')
-        result = request.get_response(self.TestRouter())
-        self.assertEqual(result.headers["Content-Type"], "application/xml")
-
-    def test_response_content_type_from_query_extension_json(self):
-        request = wsgi.Request.blank('/tests/123.json')
-        result = request.get_response(self.TestRouter())
-        self.assertEqual(result.headers["Content-Type"], "application/json")
-
-    def test_response_content_type_default_when_unsupported(self):
-        request = wsgi.Request.blank('/tests/123.unsupported')
-        request.headers["Accept"] = "application/unsupported1"
-        result = request.get_response(self.TestRouter())
-        self.assertEqual(result.status_int, 200)
-        self.assertEqual(result.headers["Content-Type"], "application/json")
-
-
-class RequestTest(test.TestCase):
-
-    def test_request_content_type_missing(self):
-        request = wsgi.Request.blank('/tests/123')
-        request.body = "<body />"
-        self.assertRaises(webob.exc.HTTPBadRequest, request.get_content_type)
-
-    def test_request_content_type_unsupported(self):
-        request = wsgi.Request.blank('/tests/123')
-        request.headers["Content-Type"] = "text/html"
-        request.body = "asdf<br />"
-        self.assertRaises(webob.exc.HTTPBadRequest, request.get_content_type)
-
-    def test_request_content_type_with_charset(self):
-        request = wsgi.Request.blank('/tests/123')
-        request.headers["Content-Type"] = "application/json; charset=UTF-8"
-        result = request.get_content_type()
-        self.assertEqual(result, "application/json")
-
-    def test_content_type_from_accept_xml(self):
-        request = wsgi.Request.blank('/tests/123')
-        request.headers["Accept"] = "application/xml"
-        result = request.best_match_content_type()
-        self.assertEqual(result, "application/xml")
-
-        request = wsgi.Request.blank('/tests/123')
-        request.headers["Accept"] = "application/json"
-        result = request.best_match_content_type()
-        self.assertEqual(result, "application/json")
-
-        request = wsgi.Request.blank('/tests/123')
-        request.headers["Accept"] = "application/xml, application/json"
-        result = request.best_match_content_type()
-        self.assertEqual(result, "application/json")
-
-        request = wsgi.Request.blank('/tests/123')
-        request.headers["Accept"] = \
-            "application/json; q=0.3, application/xml; q=0.9"
-        result = request.best_match_content_type()
-        self.assertEqual(result, "application/xml")
-
-    def test_content_type_from_query_extension(self):
-        request = wsgi.Request.blank('/tests/123.xml')
-        result = request.best_match_content_type()
-        self.assertEqual(result, "application/xml")
-
-        request = wsgi.Request.blank('/tests/123.json')
-        result = request.best_match_content_type()
-        self.assertEqual(result, "application/json")
-
-        request = wsgi.Request.blank('/tests/123.invalid')
-        result = request.best_match_content_type()
-        self.assertEqual(result, "application/json")
-
-    def test_content_type_accept_and_query_extension(self):
-        request = wsgi.Request.blank('/tests/123.xml')
-        request.headers["Accept"] = "application/json"
-        result = request.best_match_content_type()
-        self.assertEqual(result, "application/xml")
-
-    def test_content_type_accept_default(self):
-        request = wsgi.Request.blank('/tests/123.unsupported')
-        request.headers["Accept"] = "application/unsupported1"
-        result = request.best_match_content_type()
-        self.assertEqual(result, "application/json")
-
-
-class SerializerTest(test.TestCase):
-
-    def test_xml(self):
-        input_dict = dict(servers=dict(a=(2, 3)))
-        expected_xml = '<servers><a>(2,3)</a></servers>'
-        serializer = wsgi.Serializer()
-        result = serializer.serialize(input_dict, "application/xml")
-        result = result.replace('\n', '').replace(' ', '')
-        self.assertEqual(result, expected_xml)
-
-    def test_json(self):
-        input_dict = dict(servers=dict(a=(2, 3)))
-        expected_json = '{"servers":{"a":[2,3]}}'
-        serializer = wsgi.Serializer()
-        result = serializer.serialize(input_dict, "application/json")
-        result = result.replace('\n', '').replace(' ', '')
-        self.assertEqual(result, expected_json)
-
-    def test_unsupported_content_type(self):
-        serializer = wsgi.Serializer()
-        self.assertRaises(exception.InvalidContentType, serializer.serialize,
-                          {}, "text/null")
-
-    def test_deserialize_json(self):
-        data = """{"a": {
-                "a1": "1",
-                "a2": "2",
-                "bs": ["1", "2", "3", {"c": {"c1": "1"}}],
-                "d": {"e": "1"},
-                "f": "1"}}"""
-        as_dict = dict(a={
-                'a1': '1',
-                'a2': '2',
-                'bs': ['1', '2', '3', {'c': dict(c1='1')}],
-                'd': {'e': '1'},
-                'f': '1'})
-        metadata = {}
-        serializer = wsgi.Serializer(metadata)
-        self.assertEqual(serializer.deserialize(data, "application/json"),
-                         as_dict)
-
-    def test_deserialize_xml(self):
-        xml = """
-            <a a1="1" a2="2">
-              <bs><b>1</b><b>2</b><b>3</b><b><c c1="1"/></b></bs>
-              <d><e>1</e></d>
-              <f>1</f>
-            </a>
-            """.strip()
-        as_dict = dict(a={
-                'a1': '1',
-                'a2': '2',
-                'bs': ['1', '2', '3', {'c': dict(c1='1')}],
-                'd': {'e': '1'},
-                'f': '1'})
-        metadata = {'application/xml': dict(plurals={'bs': 'b', 'ts': 't'})}
-        serializer = wsgi.Serializer(metadata)
-        self.assertEqual(serializer.deserialize(xml, "application/xml"),
-                         as_dict)
-
-    def test_deserialize_empty_xml(self):
-        xml = """<a></a>"""
-        as_dict = {"a": {}}
-        serializer = wsgi.Serializer()
-        self.assertEqual(serializer.deserialize(xml, "application/xml"),
-                         as_dict)
 
=== modified file 'nova/tests/integrated/test_xml.py'
--- nova/tests/integrated/test_xml.py	2011-03-30 17:05:06 +0000
+++ nova/tests/integrated/test_xml.py	2011-05-26 21:32:29 +0000
@@ -32,7 +32,7 @@
     """"Some basic XML sanity checks."""
 
     def test_namespace_limits(self):
-        """/limits should have v1.0 namespace (hasn't changed in 1.1)."""
+        """/limits should have v1.1 namespace (has changed in 1.1)."""
         headers = {}
         headers['Accept'] = 'application/xml'
 
@@ -40,7 +40,7 @@
         data = response.read()
         LOG.debug("data: %s" % data)
 
-        prefix = '<limits xmlns="%s"' % common.XML_NS_V10
+        prefix = '<limits xmlns="%s"' % common.XML_NS_V11
         self.assertTrue(data.startswith(prefix))
 
     def test_namespace_servers(self):
 
=== modified file 'nova/wsgi.py'
--- nova/wsgi.py	2011-05-20 04:03:15 +0000
+++ nova/wsgi.py	2011-05-26 21:32:29 +0000
@@ -85,36 +85,7 @@
 
 
 class Request(webob.Request):
-
-    def best_match_content_type(self):
-        """Determine the most acceptable content-type.
-
-        Based on the query extension then the Accept header.
-
-        """
-        parts = self.path.rsplit('.', 1)
-
-        if len(parts) > 1:
-            format = parts[1]
-            if format in ['json', 'xml']:
-                return 'application/{0}'.format(parts[1])
-
-        ctypes = ['application/json', 'application/xml']
-        bm = self.accept.best_match(ctypes)
-
-        return bm or 'application/json'
-
-    def get_content_type(self):
-        allowed_types = ("application/xml", "application/json")
-        if not "Content-Type" in self.headers:
-            msg = _("Missing Content-Type")
-            LOG.debug(msg)
-            raise webob.exc.HTTPBadRequest(msg)
-        type = self.content_type
-        if type in allowed_types:
-            return type
-        LOG.debug(_("Wrong Content-Type: %s") % type)
-        raise webob.exc.HTTPBadRequest("Invalid content type")
+    pass
 
 
 class Application(object):
@@ -289,8 +260,8 @@
 
         Each route in `mapper` must specify a 'controller', which is a
         WSGI app to call.  You'll probably want to specify an 'action' as
-        well and have your controller be a wsgi.Controller, who will route
-        the request to the action method.
+        well and have your controller be an object that can route
+        the request to the action-specific method.
 
         Examples:
           mapper = routes.Mapper()
@@ -338,223 +309,6 @@
         return app
 
 
-class Controller(object):
-    """WSGI app that dispatched to methods.
-
-    WSGI app that reads routing information supplied by RoutesMiddleware
-    and calls the requested action method upon itself.  All action methods
-    must, in addition to their normal parameters, accept a 'req' argument
-    which is the incoming wsgi.Request.  They raise a webob.exc exception,
-    or return a dict which will be serialized by requested content type.
-
-    """
-
-    @webob.dec.wsgify(RequestClass=Request)
-    def __call__(self, req):
-        """Call the method specified in req.environ by RoutesMiddleware."""
-        arg_dict = req.environ['wsgiorg.routing_args'][1]
-        action = arg_dict['action']
-        method = getattr(self, action)
-        LOG.debug("%s %s" % (req.method, req.url))
-        del arg_dict['controller']
-        del arg_dict['action']
-        if 'format' in arg_dict:
-            del arg_dict['format']
-        arg_dict['req'] = req
-        result = method(**arg_dict)
-
-        if type(result) is dict:
-            content_type = req.best_match_content_type()
-            default_xmlns = self.get_default_xmlns(req)
-            body = self._serialize(result, content_type, default_xmlns)
-
-            response = webob.Response()
-            response.headers['Content-Type'] = content_type
-            response.body = body
-            msg_dict = dict(url=req.url, status=response.status_int)
-            msg = _("%(url)s returned with HTTP %(status)d") % msg_dict
-            LOG.debug(msg)
-            return response
-        else:
-            return result
-
-    def _serialize(self, data, content_type, default_xmlns):
-        """Serialize the given dict to the provided content_type.
-
-        Uses self._serialization_metadata if it exists, which is a dict mapping
-        MIME types to information needed to serialize to that type.
-
-        """
-        _metadata = getattr(type(self), '_serialization_metadata', {})
-
-        serializer = Serializer(_metadata, default_xmlns)
-        try:
-            return serializer.serialize(data, content_type)
-        except exception.InvalidContentType:
-            raise webob.exc.HTTPNotAcceptable()
-
-    def _deserialize(self, data, content_type):
-        """Deserialize the request body to the specefied content type.
-
-        Uses self._serialization_metadata if it exists, which is a dict mapping
-        MIME types to information needed to serialize to that type.
-
-        """
-        _metadata = getattr(type(self), '_serialization_metadata', {})
-        serializer = Serializer(_metadata)
-        return serializer.deserialize(data, content_type)
-
-    def get_default_xmlns(self, req):
-        """Provide the XML namespace to use if none is otherwise specified."""
-        return None
-
-
-class Serializer(object):
-    """Serializes and deserializes dictionaries to certain MIME types."""
-
-    def __init__(self, metadata=None, default_xmlns=None):
-        """Create a serializer based on the given WSGI environment.
-
-        'metadata' is an optional dict mapping MIME types to information
-        needed to serialize a dictionary to that type.
-
-        """
-        self.metadata = metadata or {}
-        self.default_xmlns = default_xmlns
-
-    def _get_serialize_handler(self, content_type):
-        handlers = {
-            'application/json': self._to_json,
-            'application/xml': self._to_xml,
-        }
-
-        try:
-            return handlers[content_type]
-        except Exception:
-            raise exception.InvalidContentType(content_type=content_type)
-
-    def serialize(self, data, content_type):
-        """Serialize a dictionary into the specified content type."""
-        return self._get_serialize_handler(content_type)(data)
-
-    def deserialize(self, datastring, content_type):
-        """Deserialize a string to a dictionary.
-
-        The string must be in the format of a supported MIME type.
-
-        """
-        return self.get_deserialize_handler(content_type)(datastring)
-
-    def get_deserialize_handler(self, content_type):
-        handlers = {
-            'application/json': self._from_json,
-            'application/xml': self._from_xml,
-        }
-
-        try:
-            return handlers[content_type]
-        except Exception:
-            raise exception.InvalidContentType(content_type=content_type)
-
-    def _from_json(self, datastring):
-        return utils.loads(datastring)
-
-    def _from_xml(self, datastring):
-        xmldata = self.metadata.get('application/xml', {})
-        plurals = set(xmldata.get('plurals', {}))
-        node = minidom.parseString(datastring).childNodes[0]
-        return {node.nodeName: self._from_xml_node(node, plurals)}
-
-    def _from_xml_node(self, node, listnames):
-        """Convert a minidom node to a simple Python type.
-
-        listnames is a collection of names of XML nodes whose subnodes should
-        be considered list items.
-
-        """
-        if len(node.childNodes) == 1 and node.childNodes[0].nodeType == 3:
-            return node.childNodes[0].nodeValue
-        elif node.nodeName in listnames:
-            return [self._from_xml_node(n, listnames) for n in node.childNodes]
-        else:
-            result = dict()
-            for attr in node.attributes.keys():
-                result[attr] = node.attributes[attr].nodeValue
-            for child in node.childNodes:
-                if child.nodeType != node.TEXT_NODE:
-                    result[child.nodeName] = self._from_xml_node(child,
-                                                                 listnames)
-            return result
-
-    def _to_json(self, data):
-        return utils.dumps(data)
-
-    def _to_xml(self, data):
-        metadata = self.metadata.get('application/xml', {})
-        # We expect data to contain a single key which is the XML root.
-        root_key = data.keys()[0]
-        doc = minidom.Document()
-        node = self._to_xml_node(doc, metadata, root_key, data[root_key])
-
-        xmlns = node.getAttribute('xmlns')
-        if not xmlns and self.default_xmlns:
-            node.setAttribute('xmlns', self.default_xmlns)
-
-        return node.toprettyxml(indent='    ')
-
-    def _to_xml_node(self, doc, metadata, nodename, data):
-        """Recursive method to convert data members to XML nodes."""
-        result = doc.createElement(nodename)
-
-        # Set the xml namespace if one is specified
-        # TODO(justinsb): We could also use prefixes on the keys
-        xmlns = metadata.get('xmlns', None)
-        if xmlns:
-            result.setAttribute('xmlns', xmlns)
-
-        if type(data) is list:
-            collections = metadata.get('list_collections', {})
-            if nodename in collections:
-                metadata = collections[nodename]
-                for item in data:
-                    node = doc.createElement(metadata['item_name'])
-                    node.setAttribute(metadata['item_key'], str(item))
-                    result.appendChild(node)
-                return result
-            singular = metadata.get('plurals', {}).get(nodename, None)
-            if singular is None:
-                if nodename.endswith('s'):
-                    singular = nodename[:-1]
-                else:
-                    singular = 'item'
-            for item in data:
-                node = self._to_xml_node(doc, metadata, singular, item)
-                result.appendChild(node)
-        elif type(data) is dict:
-            collections = metadata.get('dict_collections', {})
-            if nodename in collections:
-                metadata = collections[nodename]
-                for k, v in data.items():
-                    node = doc.createElement(metadata['item_name'])
-                    node.setAttribute(metadata['item_key'], str(k))
-                    text = doc.createTextNode(str(v))
-                    node.appendChild(text)
-                    result.appendChild(node)
-                return result
-            attrs = metadata.get('attributes', {}).get(nodename, {})
-            for k, v in data.items():
-                if k in attrs:
-                    result.setAttribute(k, str(v))
-                else:
-                    node = self._to_xml_node(doc, metadata, k, v)
-                    result.appendChild(node)
-        else:
-            # Type is atom
-            node = doc.createTextNode(str(data))
-            result.appendChild(node)
-        return result
-
-
 def paste_config_file(basename):
     """Find the best location in the system for a paste config file.