Revamp error responses

2 files changed, 19 insertions, 2 deletions

diff --git a/opendc/util/exceptions.py b/opendc/util/exceptions.py
index caf6dd8e..e73dad4f 100644
--- a/opendc/util/exceptions.py
+++ b/opendc/util/exceptions.py
@@ -55,3 +55,11 @@ class MissingParameterError(ParameterError):
 
         self.parameter_name = parameter_name
         self.parameter_location = parameter_location
+
+
+class ClientRequestError(Exception):
+    """Raised when a 4xx response is to be returned."""
+
+    def __init__(self, response):
+        super(ClientRequestError, self).__init__(str(response))
+        self.response = response
diff --git a/opendc/util/rest.py b/opendc/util/rest.py
index 33371e52..e70998a8 100644
--- a/opendc/util/rest.py
+++ b/opendc/util/rest.py
@@ -6,6 +6,7 @@ import sys
 from oauth2client import client, crypt
 
 from opendc.util import exceptions, parameter_checker
+from opendc.util.exceptions import ClientRequestError
 
 
 class Request(object):
@@ -71,14 +72,22 @@ class Request(object):
     def check_required_parameters(self, **kwargs):
         """Raise an error if a parameter is missing or of the wrong type."""
 
-        parameter_checker.check(self, **kwargs)
+        try:
+            parameter_checker.check(self, **kwargs)
+        except exceptions.ParameterError as e:
+            raise ClientRequestError(Response(400, str(e)))
 
     def process(self):
         """Process the Request and return a Response."""
 
         method = getattr(self.module, self.method)
 
-        response = method(self)
+        try:
+            response = method(self)
+        except ClientRequestError as e:
+            e.response.id = self.id
+            return e.response
+
         response.id = self.id
 
         return response