python 下载ftp服务器上文件的代码

python从ftp服务器上下载文件，代码如下：

#coding=utf-8
'''
    ftp自动下载、自动上传脚本，递归目录
'''
 
from ftplib import FTP
import os,sys,string,datetime,time
import socket
 
class MYFTP:
    def __init__(self, hostaddr, username, password, remotedir, port=21):
        self.hostaddr = hostaddr
        self.username = username
        self.password = password
        self.remotedir  = remotedir
        self.port     = port
        self.ftp      = FTP()
        self.file_list = []
        # self.ftp.set_debuglevel(2)
    def __del__(self):
        self.ftp.close()
        # self.ftp.set_debuglevel(0)
    def login(self):
        ftp = self.ftp
        try:
            timeout = 300
            socket.setdefaulttimeout(timeout)
            ftp.set_pasv(True)
            print u'开始连接到 %s' %(self.hostaddr)
            ftp.connect(self.hostaddr, self.port)
            print u'成功连接到 %s' %(self.hostaddr)
            print u'开始登录到 %s' %(self.hostaddr)
            ftp.login(self.username, self.password)
            print u'成功登录到 %s' %(self.hostaddr)
            debug_print(ftp.getwelcome())
        except Exception:
            print u'连接或登录失败'
        try:
            ftp.cwd(self.remotedir)
        except(Exception):
            print u'切换目录失败'
 
    def is_same_size(self, localfile, remotefile):
        try:
            remotefile_size = self.ftp.size(remotefile)
        except:
            remotefile_size = -1
        try:
            localfile_size = os.path.getsize(localfile)
        except:
            localfile_size = -1
        debug_print('localfile_size:%d  remotefile_size:%d' %(localfile_size, remotefile_size),)
        if remotefile_size == localfile_size:
            return 1
        else:
            return 0
    def download_file(self, localfile, remotefile):
        if self.is_same_size(localfile, remotefile):
            debug_print(u'%s 文件大小相同，无需下载' %localfile)
            return
        else:
            debug_print(u'>>>>>>>>>>>>下载文件 %s ... ...' %localfile)
        #return
        file_handler = open(localfile, 'wb')
        self.ftp.retrbinary(u'RETR %s'%(remotefile), file_handler.write)
        file_handler.close()
 
    def download_files(self, localdir='./', remotedir='./'):
        try:
            self.ftp.cwd(remotedir)
        except:
            debug_print(u'目录%s不存在，继续...' %remotedir)
            return
        if not os.path.isdir(localdir):
            os.makedirs(localdir)
        debug_print(u'切换至目录 %s' %self.ftp.pwd())
        self.file_list = []
        self.ftp.dir(self.get_file_list)
        remotenames = self.file_list
        #print(remotenames)
        #return
        for item in remotenames:
            filetype = item[0]
            filename = item[1]
            local = os.path.join(localdir, filename)
            if filetype == 'd':
                self.download_files(local, filename)
            elif filetype == '-':
                self.download_file(local, filename)
        self.ftp.cwd('..')
        debug_print(u'返回上层目录 %s' %self.ftp.pwd())
    def upload_file(self, localfile, remotefile):
        if not os.path.isfile(localfile):
            return
        if self.is_same_size(localfile, remotefile):
            debug_print(u'跳过[相等]: %s' %localfile)
            return
        file_handler = open(localfile, 'rb')
        self.ftp.storbinary('STOR %s' %remotefile, file_handler)
        file_handler.close()
        debug_print(u'已传送: %s' %localfile)
    def upload_files(self, localdir='./', remotedir = './'):
        if not os.path.isdir(localdir):
            return
        localnames = os.listdir(localdir)
        self.ftp.cwd(remotedir)
        for item in localnames:
            src = os.path.join(localdir, item)
            if os.path.isdir(src):
                try:
                    self.ftp.mkd(item)
                except:
                    debug_print(u'目录已存在 %s' %item)
                self.upload_files(src, item)
            else:
                self.upload_file(src, item)
        self.ftp.cwd('..')
 
    def get_file_list(self, line):
        ret_arr = []
        file_arr = self.get_filename(line)
        if file_arr[1] not in ['.', '..']:
            self.file_list.append(file_arr)
             
    def get_filename(self, line):
        pos = line.rfind(':')
        while(line[pos] != ' '):
            pos += 1
        while(line[pos] == ' '):
            pos += 1
        file_arr = [line[0], line[pos:]]
        return file_arr
def debug_print(s):
    print s
 
if __name__ == '__main__':
    timenow  = time.localtime()
    datenow  = time.strftime('%Y-%m-%d', timenow)
    # 配置如下变量
    hostaddr = '211.15.113.45' # ftp地址
    username = 'UserName' # 用户名
    password = '123456' # 密码
    port  =  21   # 端口号
    rootdir_local  = 'E:/mypiv' # 本地目录
    rootdir_remote = '/PIV'          # 远程目录
     
    f = MYFTP(hostaddr, username, password, rootdir_remote, port)
    f.login()
    f.download_files(rootdir_local, rootdir_remote)
     
    timenow  = time.localtime()
    datenow  = time.strftime('%Y-%m-%d', timenow)
    logstr = u"%s 成功执行了备份n" %datenow
    debug_print(logstr)