Python手册(11) WebSocket

0. 前言

• 目标：建立长连接，异步发送/接收信息。
  • 注意，只关注长连接。

1. Server

• 参考：Github: Pithikos/python-websocket-server
• 安装：
  • pip install git+https://github.com/Pithikos/python-websocket-server
  • pip install websocket-server
• 常用方法：

Method	Description	Takes	Gives
set_fn_new_client()	Sets a callback function that will be called for every new client connecting to us	function	None
set_fn_client_left()	Sets a callback function that will be called for every client disconnecting from us	function	None
set_fn_message_received()	Sets a callback function that will be called when a client sends a message	function	None
send_message()	Sends a message to a specific client. The message is a simple string.	client, message	None
send_message_to_all()	Sends a message to all connected clients. The message is a simple string.	message	None

• 注意事项：

  • 当运行了 run_forever 方法后，当前线程就阻塞了。
  • 如果在之后要调用 send_message_to_all 方法，利用多线程。

• 基本使用示例

  from websocket_server import WebsocketServer
  
  # Called for every client connecting (after handshake)
  def new_client(client, server):
  	print("New client connected and was given id %d" % client['id'])
  	server.send_message_to_all("Hey all, a new client has joined us")
  
  
  # Called for every client disconnecting
  def client_left(client, server):
  	print("Client(%d) disconnected" % client['id'])
  
  
  # Called when a client sends a message
  def message_received(client, server, message):
  	if len(message) > 200:
  		message = message[:200]+'..'
  	print("Client(%d) said: %s" % (client['id'], message))
  
  
  PORT=9001
  server = WebsocketServer(PORT)
  server.set_fn_new_client(new_client)
  server.set_fn_client_left(client_left)
  server.set_fn_message_received(message_received)
  server.run_forever()

• 多线程示例

import time
import logging
import threading
from websocket_server import WebsocketServer


def new_client(client, server):
    server.send_message_to_all("Hey all, a new client has joined us")


def message_received(client, server, message):
    if len(message) > 200:
        message = message[:200]+'..'
    print("Client(%d) said: %s" % (client['id'], message))


class ServerThread(threading.Thread):
    def __init__(self, port=13254, host='10.1.187.36', loglevel=logging.INFO):
        threading.Thread.__init__(self)
        self.server = WebsocketServer(port, host=host, loglevel=loglevel)
        self.server.set_fn_new_client(new_client)
        self.server.set_fn_message_received(message_received)
        print('init server thread successfully')

    def run(self):
        print("start running server thread")
        self.server.run_forever()


if __name__ == '__main__':
    server_thread = ServerThread()
    server_thread.start()
    while True:
        time.sleep(5)
        server_thread.server.send_message_to_all('server test msg')

2. Cleint

• 参考：Github: websocket-client/websocket-client

• 安装：pip install websocket-clien

• 注意事项：

  • url的结构形如 ws://host:ip，可能还要设置。
  • run_forever 运行后会阻塞当前线程，如果想要执行其他功能，需要设置多线程。

• 简单示例：

  import websocket
  try:
      import thread
  except ImportError:
      import _thread as thread
  import time
  
  def on_message(ws, message):
      print(message)
  
  def on_error(ws, error):
      print(error)
  
  def on_close(ws):
      print("### closed ###")
  
  def on_open(ws):
      def run(*args):
          for i in range(3):
              time.sleep(1)
              ws.send("Hello %d" % i)
          time.sleep(1)
          ws.close()
          print("thread terminating...")
      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()

• 多线程示例

  import websocket
  import threading
  websocket.enableTrace(True)
  
  
  def on_message(ws, message):
      print('on message')
      print(ws)
      print(message)
  
  
  def on_error(ws, error):
      print('on error')
      print(ws)
      print(error)
  
  
  def on_close(ws):
      print('on close')
      print(ws)
      print("### closed ###")
  
  
  class ClientThread(threading.Thread):
      def __init__(self, port=13254, host="10.1.187.36"):
          threading.Thread.__init__(self)
          url = "ws://{}:{}".format(host, port)
          self.ws = websocket.WebSocketApp(url,
                                           on_message=on_message,
                                           on_error=on_error,
                                           on_close=on_close)
          print('successfully creating client thread')
  
      def run(self):
          self.ws.run_forever()
  
  
  if __name__ == '__main__':
      client_thread = ClientThread()
      client_thread.start()
  
      import time
      while True:
          time.sleep(5)
          client_thread.ws.send('client test msg')