webui: websocket.py: Make the response message more consistent

All response message has a "success" item indicating whether the request
be successfully handled.  If anything unexpected happens, "success" is
False, and an additional "error" item presents recording the detail.

Also add some more stubs which are necessary for the Web UI.

1 files changed, 24 insertions, 11 deletions

diff --git a/fg21sim/webui/websocket.py b/fg21sim/webui/websocket.py
index 1e9b9d6..a441272 100644
--- a/fg21sim/webui/websocket.py
+++ b/fg21sim/webui/websocket.py
@@ -119,8 +119,8 @@ class FG21simWSHandler(tornado.websocket.WebSocketHandler):
         The sent message also has a ``type`` item of same value, which the
         client can be used to figure out the proper actions.
         There is a ``success`` item which indicates the status of the
-        requested operation, and a ``data`` item containing the response
-        data.
+        requested operation, and an ``error`` recording the error message
+        if ``success=False``.
         """
         logger.debug("WebSocket: %s: received: %s" % (self.name, message))
         try:
@@ -129,10 +129,14 @@ class FG21simWSHandler(tornado.websocket.WebSocketHandler):
         except json.JSONDecodeError:
             logger.warning("WebSocket: {0}: ".format(self.name) +
                            "message is not a valid JSON string")
-            response = {"success": False, "type": None}
+            response = {"success": False,
+                        "type": None,
+                        "error": "message is not a valid JSON string"}
         except (KeyError, TypeError):
             logger.warning("WebSocket: %s: skip invalid message" % self.name)
-            response = {"success": False, "type": None}
+            response = {"success": False,
+                        "type": None,
+                        "error": "type is missing"}
         else:
             # Check the message type and dispatch task
             if msg_type == "configs":
@@ -148,7 +152,9 @@ class FG21simWSHandler(tornado.websocket.WebSocketHandler):
                 # Message of unknown type
                 logger.warning("WebSocket: {0}: ".format(self.name) +
                                "unknown message type: {0}".format(msg_type))
-                response = {"success": False, "type": msg_type}
+                response = {"success": False,
+                            "type": msg_type,
+                            "error": "unknown message type %s" % msg_type}
         #
         msg_response = json.dumps(response)
         self.write_message(msg_response)
@@ -190,24 +196,31 @@ class FG21simWSHandler(tornado.websocket.WebSocketHandler):
             if msg_action == "get":
                 # Get the values of the specified options
                 data, errors = self._get_configs(keys=msg_data)
-                response["success"] = True if errors == {} else False
+                response["success"] = True
                 response["data"] = data
                 response["errors"] = errors
             elif msg_action == "set":
                 # Set the values of the specified options
                 errors = self._set_configs(data=msg_data)
-                response["success"] = True if errors == {} else False
-                response["data"] = {}
+                response["success"] = True
+                response["data"] = {}  # be more consistent
                 response["errors"] = errors
+            elif msg_action == "reset":
+                raise NotImplementedError("TODO")
+            elif msg_action == "load":
+                raise NotImplementedError("TODO")
+            elif msg_action == "save":
+                raise NotImplementedError("TODO")
             else:
                 logger.warning("WebSocket: {0}: ".format(self.name) +
                                "unknown action: {0}".format(msg_action))
                 response["success"] = False
-                response["data"] = {}
-                response["errors"] = {}
+                response["error"] = "unknown action: {0}".format(msg_action)
         except KeyError:
             # Received message has wrong syntax/format
-            response = {"success": False, "type": msg_type, "action": None}
+            response = {"success": False,
+                        "type": msg_type,
+                        "error": "no action specified"}
         #
         logger.debug("WebSocket: {0}: ".format(self.name) +
                      "response: {0}".format(response))