python FTP下载全文件

搭了一个ftp站点，没想到的是利用客户端的时候，服务器当掉了，于是自己写了一个下载ftp站点的脚本，脚本不大，不超过30行。可能利用了一点函数式的编程思想吧。
源代码：

Python代码
#/usr/bin/env python

import ftplib, sys, os

local_root = '/home/calvin/learn/tsace'
host = 'localhost'
username = 'jesse'
passewd = '123456'
f = False
writeFile = lambda filename: open(filename, 'w').write
getcwd = lambda curwd: curwd == '/' and '/' or (curwd + '/')
createDir = lambda dirname: not os.path.exists(dirname) and os.mkdir(dirname)
def isDirectory(filename):
    try:
        f.cwd(filename)
        createDir(local_root+filename)
        return True
    except:
        return False
def recursiveDownload(filelist, curpwd):
    global local_root
    map(lambda file: isDirectory(getcwd(curpwd) + file) and [recursiveDownload(f.nlst(), f.pwd())] or f.retrlines('RETR '+ (getcwd(curpwd) + file), writeFile(local_root + getcwd(curpwd) + file)), filelist)

if __name__ == '__main__':
    f = ftplib.FTP(host)
    resp = f.login(username, passewd)
    recursiveDownload(f.nlst(), f.pwd());
    f.quit()

补充：Web开发 , Python ,