gistfile1.diff

diff --git a/go/apps/jsbox/vumi_app.py b/go/apps/jsbox/vumi_app.py
index 6a84175..f5df874 100644
--- a/go/apps/jsbox/vumi_app.py
+++ b/go/apps/jsbox/vumi_app.py
@@ -5,6 +5,7 @@
 
 from twisted.internet.defer import inlineCallbacks, returnValue
 
+from vumi.config import ConfigField
 from vumi.application.sandbox import JsSandbox, SandboxResource
 from vumi.message import TransportEvent
 from vumi import log
@@ -26,6 +27,11 @@ class ConversationConfigResource(SandboxResource):
         return self.reply(command, value=value, success=True)
 
 
+class JsBoxConfig(JsSandbox.CONFIG_CLASS):
+    conversation = ConfigField("Conversation object from message.")
+    javascript = ConfigField("Javascript from message.")
+
+
 class JsBoxApplication(GoApplicationMixin, JsSandbox):
     """
     Application that processes message in a Node.js Javascript Sandbox.
@@ -44,6 +50,7 @@ class JsBoxApplication(GoApplicationMixin, JsSandbox):
     And those from :class:`vumi.application.sandbox.JsSandbox`.
     """
 
+    CONFIG_CLASS = JsBoxConfig
     SEND_TO_TAGS = frozenset(['default'])
     worker_name = 'jsbox_application'
 
@@ -71,26 +78,31 @@ class JsBoxApplication(GoApplicationMixin, JsSandbox):
         return self.get_user_api(api.conversation.user_account.key)
 
     @inlineCallbacks
-    def sandbox_protocol_for_message(self, msg_or_event):
-        """Return a sandbox protocol for a message or event.
-
-        Overrides method from :class:`Sandbox`.
-        """
-        if isinstance(msg_or_event, TransportEvent):
-            msg = yield self.find_message_for_event(msg_or_event)
-        else:
-            msg = msg_or_event
+    def get_config(self, msg=None):
+        if isinstance(msg, TransportEvent):
+            msg = yield self.find_message_for_event(msg)
 
         metadata = self.get_go_metadata(msg)
         sandbox_id = yield metadata.get_account_key()
         conversation = yield metadata.get_conversation()
-        config = conversation.metadata['jsbox']
-        javascript = config['javascript']
+
+        config = self.config.copy()
+        config.update(conversation.metadata['jsbox'])
+        config['sandbox_id'] = sandbox_id
+        config['conversation'] = conversation
+
+        returnValue(self.CONFIG_CLASS(config))
+
+    def sandbox_protocol_for_message(self, msg, config):
+        """Return a sandbox protocol for a message or event.
+
+        Overrides method from :class:`Sandbox`.
+        """
         api = self.create_sandbox_api(self.resources)
-        api.javascript = javascript
-        api.conversation = conversation
-        protocol = self.create_sandbox_protocol(sandbox_id, api)
-        returnValue(protocol)
+        api.javascript = config.javascript
+        api.conversation = config.conversation
+        protocol = self.create_sandbox_protocol(api, config)
+        return protocol
 
     def process_command_start(self, batch_id, conversation_type,
                               conversation_key, msg_options,