Usage summary of FTP communication module ftplib in Python

The ftplib module installed by default in Python defines the FTP class, which has limited functions and can be used to implement a simple ftp client for uploading or downloading files.
For the workflow and basic operations of FTP, please refer to the protocol RFC959.

ftp login connection

from ftplib import FTP #加载ftp模块
ftp=FTP() #设置变量
ftp.set_debuglevel(2) #打开调试级别2，显示详细信息
ftp.connect("IP","port") #连接的ftp sever和端口
ftp.login("user","password")#连接的用户名，密码
print ftp.getwelcome() #打印出欢迎信息
ftp.cmd("xxx/xxx") #更改远程目录
bufsize=1024 #设置的缓冲区大小
filename="filename.txt" #需要下载的文件
file_handle=open(filename,"wb").write #以写模式在本地打开文件
ftp.retrbinaly("RETR filename.txt",file_handle,bufsize) #接收服务器上文件并写入本地文件
ftp.set_debuglevel(0) #关闭调试模式
ftp.quit #退出ftp

ftp related command operations

ftp.cwd(pathname) #设置FTP当前操作的路径
ftp.dir() #显示目录下文件信息
ftp.nlst() #获取目录下的文件
ftp.mkd(pathname) #新建远程目录
ftp.pwd() #返回当前所在位置
ftp.rmd(dirname) #删除远程目录
ftp.delete(filename) #删除远程文件
ftp.rename(fromname, toname)#将fromname修改名称为toname。
ftp.storbinaly("STOR filename.txt",file_handel,bufsize) #上传目标文件
ftp.retrbinary("RETR filename.txt",file_handel,bufsize)#下载FTP文件

Example

An upload code:

import socket
from ftplib import FTP
ftp_server='xx.xx.xx.xx'
ftp_user='xxxxx'
ftp_password='xxxxx'
ftp_backup_dir='backup'
 
newday = date.today()  #获取今天的日期
oldday = date.today()-timedelta(5)  #获得5天前的日期
newfile = '/home/backup/' + 'backup_data_' + str(newday.year) + '.' + str(newday.month) + '.' + str(newday.day) + '.zip'  #本次备份文件名(绝对路径)
oldfile = '/home/backup/' + 'backup_data_' + str(oldday.year) + '.' + str(oldday.month) + '.' + str(oldday.day) + '.zip'  #5天前备份的文件名(绝对路径)
 
def upload():
  socket.setdefaulttimeout(60)  #超时FTP时间设置为60秒
  ftp = FTP(ftp_server)
  print("login ftp...")
  try:
    ftp.login(ftp_user, ftp_password)
    print(ftp.getwelcome())  #获得欢迎信息
 
    try:
      if ftp_backup_dir in ftp.nlst():
        print("found backup folder in ftp server, upload processing.")
      else:
        print("don't found backup folder in ftp server, try to build it.")
        ftp.mkd(ftp_backup_dir)
    except:
      print("the folder" + ftp_backup_dir + "doesn't exits and can't be create!")
      sys.exit()
  except:
    print("ftp login failed.exit.")
    sys.exit()
  ftp.cwd(ftp_backup_dir)  #设置FTP路径
 
  print("upload data...")
  try:
    ftp.storbinary('STOR ' + os.path.basename(newfile), open(newfile,'rb'), 1024)  #上传备份文件
  except:
    print("upload failed. check your permission.")
  
  print("delte old file...")
  try:
    ftp.delete(os.path.basename(oldfile))  #删除5天前的备份文件
  except:
    print("the old file in ftp doesn't exists, jumped.")
 
  print("ftp upload successful.exit...")
  ftp.quit()
 
if __name__== '__main__':
  upload()