WebSocket disconnects after sending ping messages

[OdCheban]

Description:
I'm experiencing an issue with the Gate.io WebSocket API where the server disconnects me after I start sending ping messages to keep the connection alive.

What I'm doing:

1. Connecting to wss://api.gateio.ws/ws/v4/
2. Subscribing to spot.obu channel for ob.BTC_USDT.50
3. Sending ping messages every 20 seconds in the following format:
   {
   "time": {time},
   "channel": "spot.ping"
   }

Expected behavior:
The server should respond with a pong message and keep the connection alive.

Actual behavior:
Initially, the server responds with pong messages
After some time (varies, but eventually), the server disconnects the WebSocket connection
The disconnection happens without any error message or warning...after 270 seconds

Code:

import json
import time
import threading
from datetime import datetime
from websocket import create_connection

class WebSocketLogger:
 def __init__(self):
 self.start_time = datetime.now()
 self.ws = None
 self.running = False
 
 def send_ping(self):
 while self.running:
 time.sleep(20)
 if self.running and self.ws:
 try:
 self.ws.send(json.dumps({
 "time": int(time.time()),
 "channel": "spot.ping"
 }))
 print(f"Sent ping")
 except Exception as e:
 print(f"Error sending ping: {e}")
 break
 
 def run(self):
 self.ws = create_connection("wss://api.gateio.ws/ws/v4/")
 print("Connected to WebSocket")
 
 self.ws.send(json.dumps({
 "time": int(time.time()),
 "channel": "spot.obu",
 "event": "subscribe",
 "payload": ["ob.BTC_USDT.50"]
 }))
 print("Sent subscription")
 
 self.running = True
 threading.Thread(target=self.send_ping, daemon=True).start()
 
 try:
 while True:
 message = self.ws.recv()
 if "pong" in message:
 print(message)
 except KeyboardInterrupt:
 elapsed = datetime.now() - self.start_time
 print(f"worked: {elapsed.seconds}.{elapsed.microseconds//1000:03d} sec")
 finally:
 self.running = False
 self.ws.close()

if __name__ == "__main__":
 WebSocketLogger().run()