Adds pre_response_handlers to Endpoints for response manipulation

pale/endpoint.py

@@ -159,6 +159,17 @@ def _execute(self, request, **kwargs):
                 HTML or XML or whatever in the future).
             The rendered JSON text is then returned as the response that should
             be sent by your HTTP framework's routing handler.
+                         *
+                         *
+        ``pre_response_handler``
+            The pre_response_handlers are sepcified by the Endpoint definition,
+            and enable manipulation of the response object before it is
+            returned to the client, but after the response is rendered.
+
+            Because these are instancemethods, they may share instance data
+            from `self` specified in the endpoint's `_handle` method.
+
+
         """
         try:
             self._create_context(request)
@@ -199,6 +210,11 @@ def _execute(self, request, **kwargs):
             logging.exception(e)
             raise e
 
+        if hasattr(self, '_pre_response_handlers') and \
+                isinstance(self._pre_response_handlers, (list, tuple)):
+            for handler in self._pre_response_handlers:
+                handler(self._context, self._context.response)
+
         return self._context.response
 
 

tests/example_app/api/endpoints.py

@@ -7,6 +7,11 @@
         DateTimeRangeResource)
 
 
+def add_cors_header(context, response):
+    """Adds a CORs definition to the response header."""
+    response.headers['Access-Control-Allow-Origin'] = "*"
+
+
 class CurrentTimeEndpoint(Endpoint):
     """An API endpoint to get the current time."""
     _http_method = "GET"
@@ -18,6 +23,8 @@ class CurrentTimeEndpoint(Endpoint):
         "server.",
         fields=DateTimeResource._all_fields())
 
+    _pre_response_handlers = (add_cors_header, )
+
     def _handle(self, context):
         now = DateTimeModel(datetime.datetime.utcnow())
         return {'time': now}

tests/test_flask_adapter.py

@@ -29,6 +29,8 @@ def assertExpectedFields(self, returned_dict, expected_fields):
     def test_successful_get_without_params(self):
         resp = self.app.get('/api/time/current')
         self.assertEqual(resp.status_code, 200)
+        self.assertIn("Access-Control-Allow-Origin", resp.headers)
+        self.assertEqual(resp.headers["Access-Control-Allow-Origin"], '*')
 
         # the 'time' value was set in the endpoint handler
         self.assertIn('time', resp.json_body)