Have an app that is using (Python 3.6) Tkinter & Tornado. Would like it send a websocket message when a button is pressed.
The sendSocket is in my class that handles the interface. I am able to open my sockets ok, and can send data into the socket handler ok. Additionally, it serves up my html file ok from my RequestHandler.
I can see that my code hits the sendSocketMessage line ok. However, I never get the print from within the SocketHandler.send_message def. There are no errors in the console.
def sendSocketMessage(self, data = "whatever"):
print("sending")
#WebSocketeer.send_message(data)
ioloop.IOLoop.current().add_callback(WebSocketeer.send_message, data)
class WebSocketeer(websocket.WebSocketHandler):
def open(self):
print("WebSocket opened")
def on_message(self, message):
print("got message: " + message)
def on_close(self):
print("WebSocket closed")
@classmethod
def send_message(self, message):
print("sending message: " + message)
for session_id, session in self.session.server._sessions._items.iteritems():
session.conn.emit(event, message)
Code based off of these SO responses
Send a websocket message: How do I send a websocket message in Tornado at will?
Send to all clients: Is it possible to send a message to all active WebSocket connections? Using either node.js or python tornado websockets
Found a way to make it work here: How to run functions outside websocket loop in python (tornado)
But am still wondering why the add_callback doesn't work - as, from what I've read, this is the recommended way.
This is what I've got working, taken from: https://github.com/tornadoweb/tornado/issues/2802
clients = [];
class WSHandler(tornado.websocket.WebSocketHandler):
def open(self):
print('connection opened...')
clients.append(self);
def on_message(self, message):
self.write_message("The server says: " + message + " back at you")
print('received:', message)
def on_close(self):
clients.remove(self);
print('connection closed...')
@classmethod
def send_message(self, message):
print("sending message: " + message)
for client in clients:
client.write_message(message);
#for session_id, session in self.session.server._sessions._items.iteritems():
# session.conn.emit(event, message);
return True;
def sendRandom():
global thread, data;
try:
print("sendRandom()");
time.sleep(0.125);
n = random.randint(0,1000);
data = str(n);
data = {"msg":"data","data":data};
if eventLoop is not None:
#If response needed
#sendData(eventLoop,WSHandler.send_message,json.dumps(data));
#else
eventLoop.add_callback(WSHandler.send_message,json.dumps(data));
except:
print("Err");
traceback.print_exc();
clients = [];
def sendData(loop,f,*a,**kw):
print("%s %s" % (type(loop),type(f)));
concurrent_future = concurrent.futures.Future();
async def wrapper():
try:
rslt = f(*a,**kw);
except Exception as e:
concurrent_future.set_exception(e);
else:
concurrent_future.set_result(rslt);
loop.add_callback(wrapper);
return concurrent_future.result();
eventLoop = None;
application = tornado.web.Application([
(r'/data', WSHandler),
])
def startServer():
global eventLoop;
try:
print("Starting server @%s:%d" %("localhost",9090));
asyncio.set_event_loop(asyncio.new_event_loop());
eventLoop = tornado.ioloop.IOLoop();
application.listen(9090)
eventLoop.start();
except KeyboardInterrupt:
print("^C");
except:
print("ERR");
traceback.print_exc();
if __name__ == "__main__":
thread = Thread(target=startServer,);
thread.setDaemon(True);
thread.start();
time.sleep(5);
while True:
sendRandom();
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