Explain several common link methods for python websocket to obtain real time data in detail

The first is to use create_connection link, which requires pip install websocket-client (this method is not recommended, the link is unstable, easy to break, and the connection is time consuming)

import time
from websocket import create_connection

url = 'wss://i.cg.net/wi/ws'
while True: # 1 Links directly and exits the loop until it is connected 
  time.sleep(2)
  try:
    ws = create_connection(url)
    print(ws)
    break
  except Exception as e:
    print(' Connection exception: ', e)
    continue
while True: #  Connect, exit the first 1 After three loops, this loop is used for 1 Direct access to data 
  ws.send('{"event":"subscribe", "channel":"btc_usdt.ticker"}')
  response = ws.recv()
  print(response)

Second, the operation effect is very good, it is easy to connect, and the speed of obtaining data is also very fast

import json
from ws4py.client.threadedclient import WebSocketClient


class CG_Client(WebSocketClient):

  def opened(self):
    req = '{"event":"subscribe", "channel":"eth_usdt.deep"}'
    self.send(req)

  def closed(self, code, reason=None):
    print("Closed down:", code, reason)

  def received_message(self, resp):
    resp = json.loads(str(resp))
    data = resp['data']
    if type(data) is dict:
      ask = data['asks'][0]
      print('Ask:', ask)
      bid = data['bids'][0]
      print('Bid:', bid)


if __name__ == '__main__':
  ws = None
  try:
    ws = CG_Client('wss://i.cg.net/wi/ws')
    ws.connect()
    ws.run_forever()
  except KeyboardInterrupt:
    ws.close()

The third kind, in fact, is similar to the first kind, but it is written in a different way. The running effect is not ideal, the connection is time-consuming, and it is easy to break

import websocket

while True:
  ws = websocket.WebSocket()
  try:
    ws.connect("wss://i.cg.net/wi/ws")
    print(ws)
    break
  except Exception as e:
    print(' Exception: ', e)
    continue
print('OK')
while True:
  req = '{"event":"subscribe", "channel":"btc_usdt.deep"}'
  ws.send(req)
  resp = ws.recv()
  print(resp)

The fourth, the running effect can also, run_forever has many parameters, need to set their own

import websocket


def on_message(ws, message): #  When the server has data update, it actively pushes the data 
  print(message)


def on_error(ws, error): #  When the program reports an error, it will trigger on_error Events 
  print(error)


def on_close(ws):
  print("Connection closed  ... ")


def on_open(ws): #  Triggered after connecting to the server on_open Event, which is used here for send Data 
  req = '{"event":"subscribe", "channel":"btc_usdt.deep"}'
  print(req)
  ws.send(req)


if __name__ == "__main__":
  websocket.enableTrace(True)
  ws = websocket.WebSocketApp("wss://i.cg.net/wi/ws",
                on_message=on_message,
                on_error=on_error,
                on_close=on_close)
  ws.on_open = on_open
  ws.run_forever(ping_timeout=30)