websocket: add disconnect and stoppd event

bfxapi/websockets/GenericWebsocket.py

@@ -38,6 +38,8 @@ class GenericWebsocket:
         self.loop = loop or asyncio.get_event_loop()
         self.events = EventEmitter(
             scheduler=asyncio.ensure_future, loop=self.loop)
+        # overide 'error' event to stop it raising an exception
+        self.events.on('error', self.on_error)
         self.ws = None
         self.max_retries = max_retries
 
@@ -72,6 +74,7 @@ class GenericWebsocket:
                 await self._connect(host)
                 retries = 0
             except (ConnectionClosed, socket.error) as e:
+                self._emit('disconnected')
                 self.logger.error(str(e))
                 retries += 1
                 # wait 5 seconds befor retrying
@@ -79,6 +82,7 @@ class GenericWebsocket:
                 await asyncio.sleep(5)
                 self.logger.info("Reconnect attempt {}/{}".format(retries, self.max_retries))
         self.logger.info("Unable to connect to websocket.")
+        self._emit('stopped')
 
     def remove_all_listeners(self, event):
         """
@@ -111,11 +115,10 @@ class GenericWebsocket:
         On websocket error print and fire event
         """
         self.logger.error(error)
-        self.events.emit('error', error)
 
     async def on_close(self):
         """
-        On websocket close print and fire event
+        On websocket close print and fire event. This is used by the data server.
         """
         self.logger.info("Websocket closed.")
         await self.ws.close()