Adding temp refs to msg_type to prevent nested dict gets.

IPython/parallel/engine/streamkernel.py

@@ -204,10 +204,11 b' class Kernel(SessionFactory):'
         
         header = msg['header']
         msg_id = header['msg_id']
-        
-        handler = self.control_handlers.get(msg['header']['msg_type'], None)
+        msg_type = header['msg_type']
+
+        handler = self.control_handlers.get(msg_type, None)
         if handler is None:
-            self.log.error("UNKNOWN CONTROL MESSAGE TYPE: %r"%msg['header']['msg_type'])
+            self.log.error("UNKNOWN CONTROL MESSAGE TYPE: %r"%msg_type)
         else:
             handler(self.control_stream, idents, msg)
     
@@ -383,17 +384,18 b' class Kernel(SessionFactory):'
         
         header = msg['header']
         msg_id = header['msg_id']
+        msg['header']['msg_type']
         if self.check_aborted(msg_id):
             self.aborted.remove(msg_id)
             # is it safe to assume a msg_id will not be resubmitted?
-            reply_type = msg['header']['msg_type'].split('_')[0] + '_reply'
+            reply_type = msg_type.split('_')[0] + '_reply'
             status = {'status' : 'aborted'}
             reply_msg = self.session.send(stream, reply_type, subheader=status,
                         content=status, parent=msg, ident=idents)
             return
-        handler = self.shell_handlers.get(msg['header']['msg_type'], None)
+        handler = self.shell_handlers.get(msg_type, None)
         if handler is None:
-            self.log.error("UNKNOWN MESSAGE TYPE: %r"%msg['header']['msg_type'])
+            self.log.error("UNKNOWN MESSAGE TYPE: %r"%msg_type)
         else:
             handler(stream, idents, msg)
     

IPython/parallel/tests/test_db.py

@@ -56,8 +56,9 b' class TestDictBackend(TestCase):'
             msg = self.session.msg('apply_request', content=dict(a=5))
             msg['buffers'] = []
             rec = init_record(msg)
-            msg_ids.append(msg['header']['msg_id'])
-            self.db.add_record(msg['header']['msg_id'], rec)
+            msg_id = msg['header']['msg_id']
+            msg_ids.append(msg_id)
+            self.db.add_record(msg_id, rec)
         return msg_ids
     
     def test_add_record(self):

IPython/zmq/ipkernel.py

@@ -122,6 +122,7 b' class Kernel(Configurable):'
         """Do one iteration of the kernel's evaluation loop.
         """
         ident,msg = self.session.recv(self.shell_socket, zmq.NOBLOCK)
+        msg_type = msg['header']['msg_type']
         if msg is None:
             return
         
@@ -133,11 +134,11 b' class Kernel(Configurable):'
         # Print some info about this message and leave a '--->' marker, so it's
         # easier to trace visually the message chain when debugging.  Each
         # handler prints its message at the end.
-        self.log.debug('\n*** MESSAGE TYPE:'+str(msg['header']['msg_type'])+'***')
+        self.log.debug('\n*** MESSAGE TYPE:'+str(msg_type)+'***')
         self.log.debug('   Content: '+str(msg['content'])+'\n   --->\n   ')
 
         # Find and call actual handler for message
-        handler = self.handlers.get(msg['header']['msg_type'], None)
+        handler = self.handlers.get(msg_type, None)
         if handler is None:
             self.log.error("UNKNOWN MESSAGE TYPE:" +str(msg))
         else: