Return 400 for invalid Json for api v2

For invalid json, a ValueError is returned by python's json decoder.
On v2, we now catch this and return a 400 (invalid_json)

Change-Id: Idb76f051c6d09d5fd26f0a44fa75a0ffd9f37b6a
Closes-Bug: #1288456

designate/api/v2/patches.py

@@ -14,6 +14,7 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 import pecan.core
+from designate import exceptions
 from designate.openstack.common import jsonutils
 
 JSON_TYPES = ('application/json', 'application/json-patch+json')
@@ -30,7 +31,10 @@ class Request(pecan.core.Request):
         is not hardcoded to call pecans "request.json()" method.
         """
         if self.content_type in JSON_TYPES:
-            return jsonutils.load(self.body_file)
+            try:
+                return jsonutils.load(self.body_file)
+            except ValueError as valueError:
+                raise exceptions.InvalidJson(valueError.message)
         else:
             raise Exception('TODO: Unsupported Content Type')
 

designate/exceptions.py

@@ -115,6 +115,10 @@ class InvalidSortKey(BadRequest):
     error_type = 'invalid_sort_key'
 
 
+class InvalidJson(BadRequest):
+    error_type = 'invalid_json'
+
+
 class InvalidOperation(BadRequest):
     error_code = 400
     error_type = 'invalid_operation'