Add on chat presence event

Last_seen time stamps were handled in unknown message type, this info is freely available and potentially useful

fbchat/client.py

@@ -1355,7 +1355,7 @@ class Client(object):
                         thread_id, thread_type = getThreadIdAndThreadType(metadata)
                         self.onMessage(mid=mid, author_id=author_id, message=message,
                                        thread_id=thread_id, thread_type=thread_type, ts=ts, metadata=metadata, msg=m)
-
+                        
                     # Unknown message type
                     else:
                         self.onUnknownMesssageType(msg=m)
@@ -1388,7 +1388,16 @@ class Client(object):
                 # Is sent before any other message
                 elif mtype == "deltaflow":
                     pass
-
+                
+                # Chat timestamp
+                elif mtype == "chatproxy-presence":
+                    buddyList = []
+                    for id in m.get("buddyList", {}).keys():
+                        payload = m["buddyList"][id]
+                        timestamp = payload["lat"]
+                        buddyList.append({id:timestamp})
+                    self.onChatTimestamp(buddylist=buddyList, msg=m)
+                    
                 # Unknown message type
                 else:
                     self.onUnknownMesssageType(msg=m)
@@ -1676,7 +1685,15 @@ class Client(object):
         """
         pass
 
+    def onChatTimestamp(self, buddylist={), msg={}):
+                                         """
+        Called when the client receives chat online presence update
 
+        :param buddylist: A list of dicts with friend id and last seen timestamp
+        :param msg: A full set of the data recieved
+        """
+        log.debug('Chat Timestamps received: {}'.format(buddylist))
+        
     def onUnknownMesssageType(self, msg={}):
         """
         Called when the client is listening, and some unknown data was recieved