diff options
Diffstat (limited to 'fg21sim/webui/handlers')
| -rw-r--r-- | fg21sim/webui/handlers/websocket.py | 107 |
1 files changed, 30 insertions, 77 deletions
diff --git a/fg21sim/webui/handlers/websocket.py b/fg21sim/webui/handlers/websocket.py index 81e5ba3..a772aa8 100644 --- a/fg21sim/webui/handlers/websocket.py +++ b/fg21sim/webui/handlers/websocket.py @@ -20,7 +20,7 @@ References import logging import tornado.websocket -from tornado.escape import json_decode, json_encode +from tornado.escape import json_encode from tornado.options import options from ..utils import get_host_ip, ip_in_network @@ -31,25 +31,40 @@ logger = logging.getLogger(__name__) class WSHandler(tornado.websocket.WebSocketHandler): """ - WebSocket for bi-directional communication between the Web UI and - the server, which can deal with the configurations and execute the - simulation task. - - Generally, WebSocket send and receive data as *string*. Therefore, - the more complex data are stringified as JSON string before sending, - which will be parsed after receive. - - Each message (as a JSON object or Python dictionary) has a ``type`` - field which will be used to determine the following action to take. + Push messages (e.g., logging messages, configurations) to the client. + + NOTE + ---- + WebSocket is a bi-directional and real-time communication protocol, which + is great for active messages pushing. + However, WebSocket is a rather low-level protocol. It receives and sends + messages independently, so it does not provide any support of + request-response operations, RPC (remote-procedure call), etc. + Therefore, it is hard/problematic to implement some interactions similar + to the traditional AJAX techniques. + + There exists some high-level sub-protocols built upon the WebSocket, e.g., + WAMP [1]_, which provides better features and are easier to use, allowing + to fully replace the AJAX etc. techniques. + However, the Tornado (v4.3) currently does not support them, and the + corresponding client JavaScript tool is also required. + + XXX/WARNING + ----------- + ``WebSocket.on_message()``: may NOT be a coroutine at the moment (v4.3). + See [2]_ and [3]_ . Attributes ---------- 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. + + References + ---------- + .. _[1] WAMP: Web Application Messaging Protocl, http://wamp-proto.org/ + .. _[2] https://stackoverflow.com/a/35543856/4856091 + .. _[3] https://stackoverflow.com/a/33724486/4856091 """ from_localhost = None @@ -100,63 +115,9 @@ class WSHandler(tornado.websocket.WebSocketHandler): self.application.ws_clients.remove(self) logger.warning("Removed closed WebSocket client: {0}".format(self)) - # FIXME/XXX: - # * How to be non-blocking ?? - # NOTE: WebSocket.on_message: may NOT be a coroutine at the moment (v4.3) - # References: - # [1] https://stackoverflow.com/a/35543856/4856091 - # [2] https://stackoverflow.com/a/33724486/4856091 - 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 ``success`` item which indicates the status of the - requested operation, and an ``error`` recording the error message - if ``success=False``. - """ - logger.debug("WebSocket: received message: {0}".format(message)) - msg = json_decode(message) - try: - msg_type = msg["type"] - except (KeyError, TypeError): - logger.warning("WebSocket: skip invalid message") - response = {"success": False, - "type": None, - "error": "type is missing"} - else: - if msg_type == "results": - # Request the simulation results - response = self._handle_results(msg) - else: - # Message of unknown type - logger.warning("WebSocket: " + - "unknown message type: {0}".format(msg_type)) - response = {"success": False, - "type": msg_type, - "error": "unknown message type %s" % msg_type} - # - msg_response = json_encode(response) - self.write_message(msg_response) - def broadcast(self, message): """Broadcast/push the given message to all connected clients.""" - for ws in self.application.ws_clients: + for ws in self.application.websockets: ws.write_message(message) def _push_configs(self): @@ -177,11 +138,3 @@ class WSHandler(tornado.websocket.WebSocketHandler): self.write_message(message) logger.info("WebSocket: Pushed current configurations data " + "with validation errors to the client") - - def _handle_results(self, msg): - # Got a message of supported types - msg_type = msg["type"] - logger.info("WebSocket: " + - "handle message of type: {0}".format(msg_type)) - response = {"success": True, "type": msg_type} - return response |