7.10 The ftplib Module

The ftplib module contains a File Transfer Protocol (FTP) client implementation.

Example 7-22 demonstrates how to log in and get a directory listing of the login directory. Note that the format of the directory listing is server dependent (it's usually the same as the format used by the directory listing utility on the server host platform).

Example 7-22. Using the ftplib Module to Get a Directory Listing

File: ftplib-example-1.py

import ftplib

ftp = ftplib.FTP("www.python.org")
ftp.login("anonymous", "ftplib-example-1")

print ftp.dir()

ftp.quit()

total 34
drwxrwxr-x  11 root     4127         512 Sep 14 14:18 .
drwxrwxr-x  11 root     4127         512 Sep 14 14:18 ..
drwxrwxr-x   2 root     4127         512 Sep 13 15:18 RCS
lrwxrwxrwx   1 root     bin           11 Jun 29 14:34 README -> welcome.msg
drwxr-xr-x   3 root     wheel        512 May 19  1998 bin
drwxr-sr-x   3 root     1400         512 Jun  9  1997 dev
drwxrwxr--   2 root     4127         512 Feb  8  1998 dup
drwxr-xr-x   3 root     wheel        512 May 19  1998 etc
...

Downloading files is easy; just use the appropriate retr function. Note that when you download a text file, you have to add line endings yourself. The function in Example 7-23 uses a lambda expression to do that on the fly.

Example 7-23. Using the ftplib Module to Retrieve Files

File: ftplib-example-2.py

import ftplib
import sys

def gettext(ftp, filename, outfile=None):
    # fetch a text file
    if outfile is None:
        outfile = sys.stdout
    # use a lambda to add newlines to the lines read from the server
    ftp.retrlines("RETR " + filename, lambda s, w=outfile.write: w(s+"\n"))

def getbinary(ftp, filename, outfile=None):
    # fetch a binary file
    if outfile is None:
        outfile = sys.stdout
    ftp.retrbinary("RETR " + filename, outfile.write)

ftp = ftplib.FTP("www.python.org")
ftp.login("anonymous", "ftplib-example-2")

gettext(ftp, "README")
getbinary(ftp, "welcome.msg")

WELCOME to python.org, the Python programming language home site.

You are number %N of %M allowed users.  Ni!

Python Web site: http://www.python.org/

CONFUSED FTP CLIENT?  Try begining your login password with '-' dash.
This turns off continuation messages that may be confusing your client.
...

Finally, Example 7-24 is a simple one that copies files to the FTP server. This script uses the file extension to figure out if the file is a text file or a binary file.

Example 7-24. Using the ftplib Module to Store Files

File: ftplib-example-3.py

import ftplib
import os

def upload(ftp, file):
    ext = os.path.splitext(file)[1]
    if ext in (".txt", ".htm", ".html"):
        ftp.storlines("STOR " + file, open(file))
    else:
        ftp.storbinary("STOR " + file, open(file, "rb"), 1024)

ftp = ftplib.FTP("ftp.fbi.gov")
ftp.login("mulder", "trustno1")

upload(ftp, "trixie.zip")
upload(ftp, "file.txt")
upload(ftp, "sightings.jpg")