python ftp client

FTP or File Transfer Protocol is an essential protocol for transferring files across different systems over a TCP network. Introduced in 1971, FTP has become a widely recognized method to share large-sized files over the internet. In Python, one can use the FTP protocol efficiently using the ftplib library.

Understanding the Basics
The ftplib library in Python provides a plethora of functions that facilitate the creation and access of remote files. Whether it’s listing directory contents or uploading files, the functions available provide a streamlined approach.

Listing Directories
The following Python snippet showcases how one can list the contents of the root directory:

import ftplib

ftp = ftplib.FTP("ftp.nluug.nl")
ftp.login("anonymous", "ftplib-example-1")

data = []

ftp.dir(data.append)

ftp.quit()

for line in data:
    print "-", line

If you have a specific directory in mind, then post-connection, utilize the ftp.cwd(‘/‘) function and specify the desired directory:

import ftplib

ftp = ftplib.FTP("ftp.nluug.nl")
ftp.login("anonymous", "ftplib-example-1")

data = []

ftp.cwd('/pub/')         # change directory to /pub/
ftp.dir(data.append)

ftp.quit()

for line in data:
    print "-", line

Downloading Files
The retrbinary() function comes in handy when downloading files. Check out the example below for a clearer understanding:

import ftplib
import sys

def getFile(ftp, filename):
    try:
        ftp.retrbinary("RETR " + filename ,open(filename, 'wb').write)
    except:
        print "Error"

ftp = ftplib.FTP("ftp.nluug.nl")
ftp.login("anonymous", "ftplib-example-1")

ftp.cwd('/pub/')         # change directory to /pub/
getFile(ftp,'README.nluug')

ftp.quit()

Uploading Files
For uploading files, the storlines() function is your best bet. The example below demonstrates the upload of the README.nluug file into the main directory:

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("127.0.0.1")
ftp.login("username", "password")

upload(ftp, "README.nluug")

Additional ftplib Functions
The ftplib library encompasses numerous functions that haven’t been covered here. For an exhaustive list and in-depth details, consult the official library documentation.

Further Learning
If you wish to delve deeper into Python programming and gain a robust understanding, consider enrolling in the Python Programming Bootcamp: Go from zero to hero.

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