Hide ZMQ serialization magic from ServerConnector clients

lib/tfw/event_handler_base.py

@@ -3,7 +3,6 @@
 
 from abc import ABC, abstractmethod
 
-from tfw.networking import deserialize_tfw_msg
 from tfw.networking.event_handlers import ServerConnector
 
 
@@ -20,14 +19,13 @@ class EventHandlerBase(ABC):
         self.subscribe(self.key, 'reset')
         self.server_connector.register_callback(self.event_handler_callback)
 
-    def event_handler_callback(self, msg_parts):
+    def event_handler_callback(self, message):
         """
         Callback that is invoked when receiving a message.
         Dispatches messages to handler methods and sends
         a response back in case the handler returned something.
         This is subscribed in __init__().
         """
-        message = deserialize_tfw_msg(*msg_parts)
         response = self.dispatch_handling(message)
         if response:
             response['key'] = message['key']

lib/tfw/networking/__init__.py

@@ -1,7 +1,7 @@
 # Copyright (C) 2018 Avatao.com Innovative Learning Kft.
 # All Rights Reserved. See LICENSE file for details.
 
-from .serialization import serialize_tfw_msg, deserialize_tfw_msg, validate_message
+from .serialization import serialize_tfw_msg, deserialize_tfw_msg, validate_message, with_deserialize_tfw_msg
 from .zmq_connector_base import ZMQConnectorBase
 # from .controller_connector import ControllerConnector # TODO: readd once controller stuff is resolved
 from .message_sender import MessageSender

lib/tfw/networking/event_handlers/server_connector.py

@@ -6,9 +6,12 @@ from functools import partial
 import zmq
 from zmq.eventloop.zmqstream import ZMQStream
 
-from tfw.networking import serialize_tfw_msg
+from tfw.networking import serialize_tfw_msg, with_deserialize_tfw_msg
 from tfw.networking import ZMQConnectorBase
 from tfw.config import TFWENV
+from tfw.config.logs import logging
+
+LOG = logging.getLogger(__name__)
 
 
 class ServerDownlinkConnector(ZMQConnectorBase):
@@ -20,7 +23,10 @@ class ServerDownlinkConnector(ZMQConnectorBase):
 
         self.subscribe = partial(self._zmq_sub_socket.setsockopt_string, zmq.SUBSCRIBE)
         self.unsubscribe = partial(self._zmq_sub_socket.setsockopt_string, zmq.UNSUBSCRIBE)
-        self.register_callback = self._zmq_sub_stream.on_recv
+
+    def register_callback(self, callback):
+        callback = with_deserialize_tfw_msg(callback)
+        self._zmq_sub_stream.on_recv(callback)
 
 
 class ServerUplinkConnector(ZMQConnectorBase):

lib/tfw/networking/serialization.py

@@ -22,6 +22,7 @@ The purpose of this module is abstracting away this low level behaviour.
 """
 
 import json
+from functools import wraps
 
 
 def validate_message(message):
@@ -36,6 +37,14 @@ def serialize_tfw_msg(message):
     return _serialize_all(message['key'], message)
 
 
+def with_deserialize_tfw_msg(fun):
+    @wraps(fun)
+    def wrapper(message_parts):
+        message = deserialize_tfw_msg(*message_parts)
+        return fun(message)
+    return wrapper
+
+
 def deserialize_tfw_msg(*args):
     """
     Return message from TFW multipart data