WebSocket和HTTP请求在工作原理和使用场景上存在显著区别。首先，HTTP是一种无状态的协议，客户端发起请求，服务器响应后，连接通常会关闭。如果客户端需要再次获取数据，必须发起新的请求。这种"请求-响应"模型适用于大多数网络应用，如网页浏览和API交互，但不适合需要实时、持续通信的场景。
WebSocket则是一种全双工通信协议，它允许客户端和服务器在建立初始连接后，保持连接持续打开。通过这个连接，双方可以随时发送数据，而无需客户端不断发起新请求。这使WebSocket成为处理实时数据的理想选择，如股票价格、聊天应用、游戏服务器等。在WebSocket连接建立后，数据的传输效率更高，因为它不需要每次通信都包含完整的HTTP头部信息。
WebSocket在订阅实时股价时具有显著优势。传统的HTTP请求通常依赖于轮询（polling）机制，即客户端定期向服务器发送请求以获取最新数据，这不仅增加了网络负载，还引入了延迟，无法实现真正的实时更新。而WebSocket则通过建立持续的全双工连接，使服务器能够在有新的股价数据时立即推送给客户端，无需轮询。这种方式极大地减少了延迟，确保用户能够实时获取股价波动。
此外，WebSocket的效率更高。与HTTP相比，WebSocket在初次连接后不会在每次通信时重新发送冗长的请求头信息，数据传输更加轻量化，节省了带宽。在需要处理高频率、大量数据的金融交易平台和量化交易中，WebSocket能够支持实时、高效的市场数据传输，让交易系统快速响应市场变化，从而为投资者提供更精确的决策支持。
因此，使用WebSocket订阅实时股价不仅降低了延迟，还优化了网络资源的使用，为高频率交易和数据密集型应用提供了理想的解决方案。
通过Websocket订阅股票价格的方法
import json
import websocket # pip install websocket-client'''
# 特别注意：
# github: https://github.com/alltick/free-quote
# token申请：https://alltick.co
# 把下面url中的testtoken替换为您自己的token
# 外汇，数字币，贵金属的api址：
# wss://quote.tradeswitcher.com/quote-b-ws-api
# 港美股api地址:
# wss://quote.tradeswitcher.com/quote-stock-b-ws-api
'''class Feed(object):def __init__(self):self.url = 'wss://quote.tradeswitcher.com/quote-stock-b-ws-api?token=testtoken' # 这里输入websocket的urlself.ws = Nonedef on_open(self, ws):"""Callback object which is called at opening websocket.1 argument:@ ws: the WebSocketApp object"""print('A new WebSocketApp is opened!')# 开始订阅（举个例子）sub_param = {"cmd_id": 22002, "seq_id": 123,"trace":"3baaa938-f92c-4a74-a228-fd49d5e2f8bc-1678419657806","data":{"symbol_list":[{"code": "700.HK","depth_level": 5,},{"code": "UNH.US","depth_level": 5,}]}}#如果希望长时间运行，除了需要发送订阅之外，还需要修改代码，定时发送心跳，避免连接断开，具体查看接口文档sub_str = json.dumps(sub_param)ws.send(sub_str)print("depth quote are subscribed!")def on_data(self, ws, string, type, continue_flag):"""4 argument.The 1st argument is this class object.The 2nd argument is utf-8 string which we get from the server.The 3rd argument is data type. ABNF.OPCODE_TEXT or ABNF.OPCODE_BINARY will be came.The 4th argument is continue flag. If 0, the data continue"""def on_message(self, ws, message):"""Callback object which is called when received data.2 arguments:@ ws: the WebSocketApp object@ message: utf-8 data received from the server"""# 对收到的message进行解析result = eval（message)print(result)def on_error(self, ws, error):"""Callback object which is called when got an error.2 arguments:@ ws: the WebSocketApp object@ error: exception object"""print(error)def on_close(self, ws, close_status_code, close_msg):"""Callback object which is called when the connection is closed.2 arguments:@ ws: the WebSocketApp object@ close_status_code@ close_msg"""print('The connection is closed!')def start(self):self.ws = websocket.WebSocketApp(self.url,on_open=self.on_open,on_message=self.on_message,on_data=self.on_data,on_error=self.on_error,on_close=self.on_close,)self.ws.run_forever()if __name__ == "__main__":feed = Feed()feed.start()解析推送数据
{"cmd_id":22998,"data":{"code": "1288.HK","seq": "1605509068000001","tick_time": "1605509068","price": "651.12","volume": "300","turnover": "12345.6","trade_direction": 1,}
}5档行情数据
{"cmd_id":22999,"data":{"code": "1288.HK","seq": "1605509068000001","tick_time": "1605509068","bids": [{"pric": "9.12","volume": "9.12",},{"pric": "9.12","volume": "9.12",},{"pric": "9.12","volume": "9.12",},{"pric": "9.12","volume": "9.12",},{"pric": "9.12","volume": "9.12",}],"asks": [{"price": "147.12","volume": "147.12",},{"price": "147.12","volume": "147.12",},{"price": "147.12","volume": "147.12",},{"price": "147.12","volume": "147.12",},{"price": "147.12","volume": "147.12",}],}
}
