python进阶 IO多路复用

• 可以监听多个文件描述符（socket对象）（文件句柄），一旦文件句柄出现变化，即可感知

  # 服务端
  import socket
  
  sk1 = socket.socket()
  sk1.bind(('127.0.0.1', 8001, ))
  sk1.listen()
  
  sk2 = socket.socket()
  sk2.bind(('127.0.0.1', 8002, ))
  sk2.listen()
  
  sk3 = socket.socket()
  sk3.bind(('127.0.0.1', 8003, ))
  sk3.listen()
  
  inputs = [sk1, sk2, sk3, ]
  import select
  while True:
      # r_list ->inputs 监听变化， w_list -> [sk1, sk2] 有什么就放如什么
      # e_list -> [] 对相应错误，1：等待的时间
      r_list, w_list, e_list = select.select(inputs, [sk1, sk2], inputs, 1)
      for sk in r_List:
          # print(sk)
          # 每一个连接对象
          conn, address = sk.accept()
          conn.sendall(bytes('hello', encoding='utf-8'))
          # conn.close()
      for sk in e_list:
          # 哪一个连接出错就移除它
          inputs.remove(sk)
  # ---------------------------------------------------------------------------
  # 客户端1
  import socket
  
  obj = socket.socket()
  obj.connect(('127.0.0.1', 8001))
  
  content = str(obj.recv(1024), encoding='utf-8')
  print(content)
  obj.close()
  # --------------------------------------------------------------------------
  # 客户端2
  import socket
  
  obj = socket.socket()
  obj.connect(('127.0.0.1', 8002))
  
  content = str(obj.recv(1024), encoding='utf-8')
  print(content)
  obj.close()
  

• 基于IO多路复用select+socket实现伪并发

  # 服务端
  import socket
  
   sk1 = socket.socket()
   sk1.bind(('127.0.0.1', 8001, ))
   sk1.listen()
  
   inputs = [sk1,  ]
   outputs = []
   message_dict = {}
  
   import select
   while True:
       r_list, w_list, e_list = select.select(inputs, outputs, inputs, 1)
       print('正在监听的socket对象有%d个', len(inputs))
       print(r_list)
       for sk1_or_conn in r_List:
           # 每一个连接对象
           if sk1_or_conn == sk1:
               # 表示有新用户来连接
               conn, address = sk1_or_conn.accept()
               inputs.append(conn)
               message_dict[conn] = []
           else:
               # 有老用户发消息了
               try:
                   data_bytes = sk1_or_conn.recv(1024)
               except Exception as e:
                   inputs.remove(sk1_or_conn)
               else:
                    data_str = str(data_bytes, encoding='utf-8')
                    message_dict[sk1_or_conn].append(data_str)
        # w_list仅仅保存了谁给我发过消息
        for conn in w_list:
            recv_str = message_dict[conn][0]
            del message_dict[conn][0]
            conn.sendall(bytes(recv_str + '好', encoding='utf-8'))
            outputs.remove(conn)
        for sk in e_list:
            inputs.remove(sk)
   # -------------------------------------------------------------------------
   # 客户端
   import socket
  
   obj = socket.socket()
   obj.connect(('127.0.0.1', 8001))
  
   while True:
       inp = input('>>>>')
       obj.sendall(bytes(inp, encoding='utf-8'))
       ret = str(obj.recv(1024), encoding='utf-8')
       print(ret)
  
  obj.close()