python ftplib下载文件封装

原用于下载ftp中文路径图片封装代码

1. 支持指定用户密码和端口

   ftp://ftpuser:ftppasswd@192.168.2.157:21/test.png

2. 支持中文

   ftp://192.168.2.157/测试1/test.png

思路逻辑：

1. ftp url分析是否有用户验证和端口指定
2. 使用ftp.retrbinary下载文件，StringIO.StringIO()作缓存

直接上代码

# coding:utf-8
import sys
import urlparse
import ftplib
import traceback
import StringIO

# used to down ftp file with auth and chinese character
def ftpdown(url, timeout=3):
    lasterr = ''
    for i in range(3):
        urlps = urlparse.urlparse(url)
        if '@' not in urlps.netloc:
            user = ''
            passwd = ''
            host = urlps.netloc
            port = 21
        else:
            urlhead = urlps.netloc.split('@')
            if len(urlhead) != 2:
                lasterr = 'url fromat err'
                continue
            else:
                user, passwd = urlhead[0].split(':')
                if ':' not in urlhead[1]:
                    host = urlhead[1]
                    port = 21
                else:
                    host, port = urlhead[1].split(':')

        try:
            ftp = ftplib.FTP()
            ftp.connect(host=host, port=port, timeout=timeout)
            ftp.login(user=user, passwd=passwd)
        except Exception:
            print(traceback.format_exc())
            continue
        try:
            buf = StringIO.StringIO()
            ftp.retrbinary('RETR ' + urlps.path, buf.write)
            ftp.close()
            return buf.getvalue()
        except Exception:
            lasterr = traceback.format_exc()
            continue
    print('exception occurs when ftp get url[%s], err[%s]' % (url, lasterr))
    return None

参考文档：https://www.cnblogs.com/kaituorensheng/p/4480512.html