python使用socket实现的传输demo示例【基于TCP协议】

import socket
def main():
  tcp_client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
  # 服务器位于本机 9999
  tcp_client_socket.connect( ("192.168.27.72", 9999) )
  # 告诉服务器，我要下载哪一个文件
  file_name = input("请输入要下载的文件名:")
  tcp_client_socket.send(file_name.encode("utf-8"))
  temp = tcp_client_socket.recv(1024)
  print(temp)
  file_length = int(temp.decode("utf-8"))
  # 接收数据 字节
  recv_data = tcp_client_socket.recv(file_length)
  # 得到数据，需要将数据写入文件
  if recv_data:
    # f = open("new_" + file_name, "wb")
    # try:
    #   f.write(recv_data)
    # except Exception as result:
    #   print("写入文件错误")
    # finally:
    #   f.close()
    with open("new_" + file_name, "wb") as f:
      f.write(recv_data)
  tcp_client_socket.close()
if __name__ == '__main__':
  main()

import socket
def main():
  #1创建套接字
  tcp_server_socket = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
  #2绑定本地信息bind
  tcp_server_socket.bind(('',9999))
  #3让默认的套接字由主动变为被动listen ????
  tcp_server_socket.listen(128)
  #4等待别人的电话到来（等待客户端的链接 accept）
  new_client_socket, client_addr = tcp_server_socket.accept()
  #5调用发送文件函数，完成为客户端服务
  rece_data = new_client_socket.recv(1024)
  file_name = rece_data.decode('utf-8')
  try:
    f = open(file_name, 'rb')
    content = f.read()
    file_length = len(content)
    print(file_length)
    new_client_socket.send(str(file_length).encode('utf-8'))   #????1两个发送第二个执行快了怎么办？
    new_client_socket.send(content)
  except Exception as f:
    print('文件打开失败')
  # 6关闭套接字
  new_client_socket.close()
  tcp_server_socket.close()
if __name__ == '__main__':
  main()