Python - 如何使用 websocket-client 发送心跳？

Question

The server requires the client to send a heartbeat every 30 seconds to keep the connection alive. How can I achieve this using python websocket-client library?

import websocket
def on_open(ws):
     pass
def on_close(ws):
     pass
def on_message(ws, message):
     pass

socket = "wss:// the rest of the url"
ws = websocket.WebSocketApp(socket, on_open=on_open,on_message=on_message)
ws.run_forever()

No code runs after ws.run_forever(). How can I send messages? Thank you

Answer 1

In the library documentation there is a Long-lived connection example. Modifying it for your use case, it should look something like this. I used 28 seconds between heartbeats, since you said the 30 sec is the expected duration. If this is critical, I would use 14 seconds to make it more robust for network issues.

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


.. code removed for brevity ..


def on_open(ws):
    def run(*args):
        while True:
            time.sleep(28)
            ws.send("Ping")

    thread.start_new_thread(run, ())


if __name__ == "__main__":
    websocket.enableTrace(True)
    ws = websocket.WebSocketApp("ws://echo.websocket.org/",
                              on_message = on_message,
                              on_error = on_error,
                              on_close = on_close)
    ws.on_open = on_open
    ws.run_forever()

Answer 2

run_forever has ping_interval argument. Eg. ws.run_forever( ping_interval=14) can be used for your purpose.