import socket
 
# 1.創建套接字
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# 2.綁定端口
server.bind(('127.0.0.1', 7890))
# 3.變為被動監聽模式
server.listen(4)
while True:
  # 4.等待客戶端鏈接
  s_new, addr = server.accept()
  print('用戶【{}】已經成功連接！！'.format(addr[0]))
  while True:
    # 5.接受消息
    try:
      # 若客戶端強行斷開連接服務器不會崩潰
      recv_data = s_new.recv(1024).decode('utf-8')
      if recv_data:
        print('來自【{}】的用戶表示要下載： 【{}】'.format(addr[0], recv_data))
        # 6.發送消息
        try:
          f = open(recv_data, 'rb')
          content = f.read()
          send_data = s_new.send(content)
          f.close()
          print('下載成功！')
        except Exception as result:
          send_data = s_new.send('Non'.encode('utf-8'))
          print('未找到要下載的文件')
      else:
        print('用戶已經正常退出！')
        break
    except Exception as res:
      print('用戶已經退出連接！')
      break
  s_new.close()
# 7，關閉套接字
server.close()

import socket
# 創建套接字
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# 綁定IP地址
s.connect(('127.0.0.1', 7890))
while True:
 
  # 發送數據
  send_data = str(input('請輸入想要下載的文件名：'))
  if send_data == 'exit':
    print('已退出下載！')
    break
  s.send(send_data.encode('utf-8'))
 
  # 接收數據
  recv_data = s.recv(2048)
  if recv_data == 'Non'.encode('utf-8'):
    print('未找到要下載的文件！')
  else:
    with open('【new】' + send_data, 'wb') as f:
      f.write(recv_data)
      print('[{}]下載成功！'.format(send_data))
      f.close()
 
# 關閉套接字
s.close()