Python 下载FTP所有昨天生成的文件（递归）

#!/usr/bin/env python
# -*- encoding: utf8 -*-
# Mr.Wang

import os
import sys
import ftplib
import time

mytime = time.strftime('%Y%m%d',time.localtime(time.time() - 24*60*60))

class FTPSync(object):
    def __init__(self):
        self.conn = ftplib.FTP('XXX.XXX.XXX.XXX', 'user', 'password')
        self.conn.cwd('/') # 远端FTP目录
        os.chdir('/data/ftp/') # 本地下载目录
    def get_dirs_files(self):
        u''' 得到当前目录和文件, 放入dir_res列表 '''
        dir_res = []
        self.conn.dir('.', dir_res.append)
        files = [f.split(None, 8)[-1] for f in dir_res if f.startswith('-')]
        dirs = [f.split(None, 8)[-1] for f in dir_res if f.startswith('d')]
        return (files, dirs)
    def walk(self, next_dir):
        print 'Walking to', next_dir
        self.conn.cwd(next_dir)
        try:
            os.mkdir(next_dir)
        except OSError:
            pass
        os.chdir(next_dir)
        ftp_curr_dir = self.conn.pwd()
        local_curr_dir = os.getcwd()
        files, dirs = self.get_dirs_files()
        print "FILES: ", files
        print "DIRS: ", dirs
        for f in files:
                        if mytime in f:
                                print next_dir, ':', f
                                outf = open(f, 'wb')
                                try:
                                        self.conn.retrbinary('RETR %s' % f, outf.write)
                                finally:
                                        outf.close()
        for d in dirs:
            os.chdir(local_curr_dir)
            self.conn.cwd(ftp_curr_dir)
            self.walk(d)
    def run(self):
        self.walk('.')
def main():
    f = FTPSync()
    f.run()
if __name__ == '__main__':
    main()