Add a NULL terminator to the data we send out to clients

* When sending data from Python to a C client via a ZeroMQ socket
  we need to make sure that the data on the client side can be
  properly understood by the client

src/vpoller/client.py

@@ -93,7 +93,7 @@ def run(self, msg):
             # Do we have a reply?
             if socks.get(self.zclient) == zmq.POLLIN:
                 logging.debug('Received response on client socket')
-                result = self.zclient.recv_json()
+                result = self.zclient.recv()
                 logging.debug('Received message was: %s', result)
                 break
             else:

src/vpoller/worker.py

@@ -27,6 +27,7 @@
 
 """
 
+import json
 import logging
 import importlib
 import multiprocessing
@@ -458,7 +459,11 @@ def wait_for_tasks(self):
             self.worker_socket.send(_id, zmq.SNDMORE)
             self.worker_socket.send(_empty, zmq.SNDMORE)
             try:
-                self.worker_socket.send_json(result)
+                # Add a NULL terminator at the end of the result
+                # so that C clients can properly get the data we send
+                data = json.dumps(result, ensure_ascii=False)
+                data += '\0'
+                self.worker_socket.send(data)
             except TypeError as e:
                 logging.warning('Cannot serialize result: %s', e)
                 r = {'success': 1, 'msg': 'Cannot serialize result: %s' % e}