python websocketapp on_message() 方法不起作用

Question

I use python to receive streaming data from nodejs server, with the following python code. The websocket suppose to get real time streaming data. And I assume the only way for python's WebSocketApp to get the streaming data is via on_message().

However, despite connection can be successfully established, the on_message() is never called. on_open() still called, and ping message has been routinely sent to the server to maintain the heartbeat.

I searched through the internet and cannot find a clue as of what's happening that makes on_message() failures?

I tested the connection locally and remotely, connection is good.

import websocket
from websocket import create_connection


import json
try:
    import thread
except ImportError:
    import _thread as thread
import time

def on_message(ws, message):
    print('on msg called')
    print(message)

def on_error(ws, error):
    print(error)

def on_close(ws):
    time.sleep(1)
    ws.close()
    print("### closed ###")


def on_open(ws):
    def run(*args):
        time.sleep(1)
        print('sending from run()...')
        ws.send("{\"login\":\"login\",\"password\":\"pw\"}")
        time.sleep(1)

        try:
            print('receiving message...')
            #result =  json.loads(ws.receive())
            #result = ws.recv_frame()
            #result = json.loads(ws.recv())
            #print(result)
        except Exception as e:
            print('failed to receive messages...')
            print(e)
            time.sleep(1)
            ws.close()        

    thread.start_new_thread(run, ())


if __name__ == "__main__":
    try:
        websocket.enableTrace(True)         # show the header part 
        ws = websocket.WebSocketApp("ws://localhost:4010",
                                  subprotocols=["echo-protocol"],
                                  on_message = on_message,
                                  on_error = on_error,
                                  on_close = on_close)
        ws.on_open = on_open
        ws.run_forever(ping_interval=0,ping_timeout=0)
    except KeyboardInterrupt:
        ws.close()

it is believed that upon successful retrieval, info would be passed back in json format.

Answer 1

It seems that with your code, the on_message inside the class WebsockeApp is called, and not that one you have in your code. To let run the on_message in your code, just make an own class inside your code and then change in your object creation to

From:

on_message = on_message

To:

ws = websocket.WebSocketApp("ws://localhost:4010", subprotocols=["echo-protocol"], on_message = YourClassName.on_message, on_error = on_error, on_close = on_close)