python实例:使用一个对象实例作为一个FTP回调

#!/usr/bin/python
#
#site: WWW.jb200.com

class Writer:
    def __init__(self, file):
        self.f = open(file, "w")

    def __call__(self, data):
        self.f.write(data)
        self.f.write('n')
        print data

FILENAME = "AutoIndent.py"
writer = Writer(FILENAME)

import ftplib
ftp = ftplib.FTP('127.0.0.1', 'book', 'bookpw')
ftp.retrlines("RETR %s" % FILENAME, writer)