# coding:utf8
from ftplib import FTP


def upload(f, remote_path, local_path):
    fp = open(local_path, "rb")
    buf_size = 1024
    f.storbinary("STOR {}".format(remote_path), fp, buf_size)
    fp.close()


def download(f, remote_path, local_path):
    fp = open(local_path, "wb")
    buf_size = 1024
    f.retrbinary(‘RETR {}‘.format(remote_path), fp.write, buf_size)
    fp.close()


if __name__ == "__main__":
    ftp = FTP()
    ftp.connect("x.x.x.x", 21)      # 第一个参数可以是ftp服务器的ip或者域名，第二个参数为ftp服务器的连接端口，默认为21
    ftp.login(username, password)     # 匿名登录直接使用ftp.login()
    ftp.cwd("tmp")                # 切换到tmp目录
    upload(ftp, "ftp_a.txt", "a.txt")   # 将当前目录下的a.txt文件上传到ftp服务器的tmp目录，命名为ftp_a.txt
    download(ftp, "ftp_a.txt", "b.txt")  # 将ftp服务器tmp目录下的ftp_a.txt文件下载到当前目录，命名为b.txt
    ftp.quit()