Enhance V3 version controller to provide JSON Home response

The V3 version controller would only respond with the normal version
JSON response. With this change, if the Accept header is
`application/json-home` it will respond with a JSON Home response
which includes all the registered JSON Home data. Note that there is
no JSON Home data yet so the response is empty.

bp json-home

Change-Id: Icfde89040b376bd6704d497966bd8ad109e32d08

keystone/common/wsgi.py

@@ -686,7 +686,10 @@ def render_response(body=None, status=None, headers=None, method=None):
             content_type = content_types[0]
         else:
             content_type = None
-        if content_type is None or content_type == 'application/json':
+
+        JSON_ENCODE_CONTENT_TYPES = ('application/json',
+                                     'application/json-home',)
+        if content_type is None or content_type in JSON_ENCODE_CONTENT_TYPES:
             body = jsonutils.dumps(body, cls=utils.SmarterEncoder)
             if content_type is None:
                 headers.append(('Content-Type', 'application/json'))

keystone/controllers.py

@@ -143,9 +143,25 @@ class Version(wsgi.Application):
         else:
             raise exception.VersionNotFound(version='v2.0')
 
+    def _get_json_home_v3(self):
+
+        def all_resources():
+            for router in self._routers:
+                for resource in router.v3_resources:
+                    yield resource
+
+        return {
+            'resources': dict(all_resources())
+        }
+
     def get_version_v3(self, context):
         versions = self._get_versions_list(context)
         if 'v3' in _VERSIONS:
+            if context['headers'].get('Accept') == 'application/json-home':
+                return wsgi.render_response(
+                    body=self._get_json_home_v3(),
+                    headers=(('Content-Type', 'application/json-home'),))
+
             return wsgi.render_response(body={
                 'version': versions['v3']
             })

keystone/tests/test_versions.py

@@ -16,6 +16,7 @@
 import random
 
 import mock
+from testtools import matchers as tt_matchers
 
 from keystone import config
 from keystone import controllers
@@ -101,6 +102,8 @@ VERSIONS_RESPONSE = {
     }
 }
 
+V3_JSON_HOME_RESOURCES = {}
+
 
 class VersionTestCase(tests.TestCase):
     def setUp(self):
@@ -296,6 +299,23 @@ class VersionTestCase(tests.TestCase):
         data = jsonutils.loads(resp.body)
         self.assertEqual(data, v2_only_response)
 
+    def test_json_home_v3(self):
+        # If the request is /v3 and the Accept header is application/json-home
+        # then the server responds with a JSON Home document.
+
+        client = self.client(self.public_app)
+        resp = client.get('/v3', headers={'Accept': 'application/json-home'})
+
+        self.assertThat(resp.status, tt_matchers.Equals('200 OK'))
+        self.assertThat(resp.headers['Content-Type'],
+                        tt_matchers.Equals('application/json-home'))
+
+        exp_json_home_data = {
+            'resources': V3_JSON_HOME_RESOURCES}
+
+        self.assertThat(jsonutils.loads(resp.body),
+                        tt_matchers.Equals(exp_json_home_data))
+
 
 class XmlVersionTestCase(tests.TestCase):