More generally, this script (shown in Example 13-10) will download a directory full of
files to any machine with Python and sockets, from any machine running an FTP server.

Example 13-10. PP4E\Internet\Ftp\Mirror\downloadflat.py

#!/bin/env python
"""
###############################################################################
use FTP to copy (download) all files from a single directory at a remote
site to a directory on the local machine; run me periodically to mirror
a flat FTP site directory to your ISP account; set user to 'anonymous'
to do anonymous FTP; we could use try to skip file failures, but the FTP
connection is likely closed if any files fail; we could also try to
reconnect with a new FTP instance before each transfer: connects once now;
if failures, try setting nonpassive for active FTP, or disable firewalls;
this also depends on a working FTP server, and possibly its load policies.
###############################################################################
"""

import os, sys, ftplib
from getpass import getpass
from mimetypes import guess_type

nonpassive = False # passive FTP on by default in 2.1+
remotesite = 'home.rmi.net' # download from this site
remotedir = '.' # and this dir (e.g., public_html)
remoteuser = 'lutz'
remotepass = getpass('Password for %s on %s: ' % (remoteuser, remotesite))
localdir = (len(sys.argv) > 1 and sys.argv[1]) or '.'
cleanall = input('Clean local directory first? ')[:1] in ['y', 'Y']

print('connecting...')
connection = ftplib.FTP(remotesite) # connect to FTP site
connection.login(remoteuser, remotepass) # login as user/password
connection.cwd(remotedir) # cd to directory to copy
if nonpassive: # force active mode FTP
connection.set_pasv(False) # most servers do passive

if cleanall:
for localname in os.listdir(localdir): # try to delete all locals
try: # first, to remove old files
print('deleting local', localname) # os.listdir omits. and ..
os.remove(os.path.join(localdir, localname))
except:
print('cannot delete local', localname)

count = 0 # download all remote files
remotefiles = connection.nlst() # nlst() gives files list

dir() gives full details

for remotename in remotefiles:
if remotename in ('.', '..'): continue # some servers include. and ..
mimetype, encoding = guess_type(remotename) # e.g., ('text/plain', 'gzip')
mimetype = mimetype or '?/?' # may be (None, None)
maintype = mimetype.split('/')[0] # .jpg ('image/jpeg', None')

Transferring Directories with ftplib | 875