webui: Update server & client sides WebSocket handlers

* Server side:
  + Update the "on_message()" method to support 3 types of message
    requests (i.e., "configs", "console", and "results");
  + Add messages stub handlers: "_handle_{configs,console,results}()";
  + Reorder the methods

+ Client side:
  + Change timeout before reconnection to 3000 ms;
  + Parse the received JSON message to JS object;

2 files changed, 104 insertions, 24 deletions

diff --git a/fg21sim/webui/static/js/websocket.js b/fg21sim/webui/static/js/websocket.js
index 95e85f2..ae44410 100644
--- a/fg21sim/webui/static/js/websocket.js
+++ b/fg21sim/webui/static/js/websocket.js
@@ -16,7 +16,7 @@ var ws = null;  /* WebSocket */
 var ws_reconnect = {
   maxTry: 100,
   tried: 0,
-  timeout: 1000,  /* ms */
+  timeout: 3000,  /* ms */
 };
 
 
@@ -130,8 +130,9 @@ var connectWebSocket = function (url) {
     toggleWSReconnect("show");
   };
   ws.onmessage = function (e) {
-    console.log("WebSocket received message:");
-    console.log(e.data);
+    var msg = JSON.parse(e.data);
+    console.log("WebSocket received message: type:", msg.type,
+                ", status:", msg.status);
   };
 };
 
diff --git a/fg21sim/webui/websocket.py b/fg21sim/webui/websocket.py
index 0677f83..d1501b5 100644
--- a/fg21sim/webui/websocket.py
+++ b/fg21sim/webui/websocket.py
@@ -17,10 +17,12 @@ References
   http://caniuse.com/#feat=websockets
 """
 
+import json
 import logging
 
 import tornado.websocket
 
+from ..configs import ConfigManager
 from .utils import get_host_ip
 
 
@@ -47,30 +49,13 @@ class FG21simWSHandler(tornado.websocket.WebSocketHandler):
     from_localhost : bool
         Set to ``True`` if the access is from the localhost,
         otherwise ``False``.
+    configs : `~ConfigManager`
+        A ``ConfigManager`` instance, for configuration manipulations when
+        communicating with the Web UI.
     """
     name = "fg21sim"
     from_localhost = None
-
-    def open(self):
-        """Invoked when a new WebSocket is opened by the client."""
-        logger.info("WebSocket: %s: opened" % self.name)
-
-    def on_message(self, message):
-        """Handle incoming messages."""
-        logger.info("WebSocket: %s: received: %s" % (self.name, message))
-        msg_back = message[::-1]
-        logger.info("WebSocket: %s: sent: %s" % (self.name, msg_back))
-        self.write_message(msg_back)
-
-    def on_close(self):
-        """Invoked when a new WebSocket is closed by the client."""
-        code, reason = None, None
-        if hasattr(self, "close_code"):
-            code = self.close_code
-        if hasattr(self, "close_reason"):
-            reason = self.close_reason
-        logger.info("WebSocket: {0}: closed by client: {1}, {2}".format(
-            self.name, code, reason))
+    configs = ConfigManager()
 
     def check_origin(self, origin):
         """Check the origin of the WebSocket access.
@@ -98,3 +83,97 @@ class FG21simWSHandler(tornado.websocket.WebSocketHandler):
             logger.error("WebSocket: %s: " % self.name +
                          "ONLY allow access from localhost at the moment :(")
             return False
+
+    def open(self):
+        """Invoked when a new WebSocket is opened by the client."""
+        logger.info("WebSocket: %s: opened" % self.name)
+
+    def on_close(self):
+        """Invoked when a new WebSocket is closed by the client."""
+        code, reason = None, None
+        if hasattr(self, "close_code"):
+            code = self.close_code
+        if hasattr(self, "close_reason"):
+            reason = self.close_reason
+        logger.info("WebSocket: {0}: closed by client: {1}, {2}".format(
+            self.name, code, reason))
+
+    def on_message(self, message):
+        """Handle incoming messages and dispatch task according to the
+        message type.
+
+        NOTE
+        ----
+        The received message (parsed to a Python dictionary) has a ``type``
+        item which will be used to determine the following action to take.
+
+        Currently supported message types are:
+        ``configs``:
+            Request or set the configurations
+        ``console``:
+            Control the simulation tasks, or request logging messages
+        ``results``:
+            Request the simulation results
+
+        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 ``status`` item which indicates the status of the
+        requested operation, and a ``data`` item containing the response
+        data.
+        """
+        logger.debug("WebSocket: %s: received: %s" % (self.name, message))
+        try:
+            msg = json.loads(message)
+            msg_type = msg["type"]
+        except json.JSONDecodeError:
+            logger.warning("WebSocket: {0}: ".format(self.name) +
+                           "message is not a valid JSON string")
+        except (KeyError, TypeError):
+            logger.warning("WebSocket: %s: skip invalid message" % self.name)
+        finally:
+            response = {"status": False, "type": None}
+            msg_response = json.dumps(response)
+            self.write_message(msg_response)
+            return
+
+        # Check the message type and dispatch task
+        if msg_type == "configs":
+            # Request or set the configurations
+            response = self._handle_configs(msg)
+        elif msg_type == "console":
+            # Control the simulation tasks, or request logging messages
+            response = self._handle_console(msg)
+        elif msg_type == "results":
+            # Request the simulation results
+            response = self._handle_results(msg)
+        else:
+            # Message of unknown type
+            logger.warning("WebSocket: {0}: ".format(self.name) +
+                           "message of unknown type: {0}".format(msg_type))
+            response = {"status": False, "type": msg_type}
+        msg_response = json.dumps(response)
+        self.write_message(msg_response)
+
+    def _handle_configs(self, msg):
+        # Got a message of supported types
+        msg_type = msg["type"]
+        logger.info("WebSocket: {0}: ".format(self.name) +
+                    "handle message of type: {0}".format(msg_type))
+        response = {"status": True, "type": msg_type}
+        return response
+
+    def _handle_console(self, msg):
+        # Got a message of supported types
+        msg_type = msg["type"]
+        logger.info("WebSocket: {0}: ".format(self.name) +
+                    "handle message of type: {0}".format(msg_type))
+        response = {"status": True, "type": msg_type}
+        return response
+
+    def _handle_results(self, msg):
+        # Got a message of supported types
+        msg_type = msg["type"]
+        logger.info("WebSocket: {0}: ".format(self.name) +
+                    "handle message of type: {0}".format(msg_type))
+        response = {"status": True, "type": msg_type}
+        return response