`ftplib`

The Python ftplib module implements the client side of the File Transfer Protocol (FTP), allowing Python programs to connect to FTP servers and transfer files programmatically.

Here’s a quick look at listing a directory on an FTP server:

from ftplib import FTP

with FTP("ftp.example.com") as ftp:
    ftp.login()
    ftp.cwd("pub")
    print(ftp.nlst())
# ['README', 'data.tar.gz', 'changelog.txt']

The module provides two classes: FTP for plain connections and FTP_TLS for connections secured with TLS.

Note: The ftp.example.com server is a placeholder and won’t respond if you run the code snippets as they are. Replace the hostname and credentials with your own to try the examples against a real server.

Key Features

Implements RFC 959 with UTF-8 encoding support per RFC 2640
Supports both binary and line-mode file transfers
Uses passive mode by default, which works through most firewalls
Provides FTP_TLS for TLS-encrypted control connections and opt-in data channel encryption via prot_p()
Supports context manager usage for automatic connection cleanup
Covers directory listing, navigation, upload, download, rename, and delete operations

Frequently Used Classes and Functions

Object	Type	Description
`ftplib.FTP`	Class	Opens a plain FTP connection to a server
`ftplib.FTP_TLS`	Class	Opens an FTP connection secured with TLS
`FTP.login()`	Method	Authenticates with the server (defaults to anonymous login)
`FTP.retrbinary()`	Method	Downloads a file in binary mode by passing each block to a callback
`FTP.storbinary()`	Method	Uploads a file in binary mode from a file-like object
`FTP.retrlines()`	Method	Downloads a file or directory listing line by line
`FTP.mlsd()`	Method	Lists a directory in standardized format, returning filename and metadata pairs
`FTP.cwd()`	Method	Changes the working directory on the server
`FTP.pwd()`	Method	Returns the current working directory path on the server
`FTP.delete()`	Method	Deletes a file from the server
`FTP.rename()`	Method	Renames or moves a file on the server
`ftplib.all_errors`	Tuple	Contains all ftplib exception types for broad error handling

Examples

Downloading a file in binary mode:

from ftplib import FTP

with FTP("ftp.example.com") as ftp:
    ftp.login()
    with open("data.tar.gz", "wb") as f:
        ftp.retrbinary("RETR data.tar.gz", f.write)

Uploading a file in binary mode:

from ftplib import FTP

with FTP("ftp.example.com") as ftp:
    ftp.login("alice", "secret")
    with open("report.pdf", "rb") as f:
        ftp.storbinary("STOR report.pdf", f)

Connecting securely with FTP_TLS and protecting the data channel:

from ftplib import FTP_TLS

with FTP_TLS("ftp.example.com") as ftps:
    ftps.login("alice", "secret")
    ftps.prot_p()  # Secure the data connection
    ftps.cwd("uploads")
    with open("backup.tar.gz", "rb") as f:
        ftps.storbinary("STOR backup.tar.gz", f)

Common Use Cases

The most common tasks for ftplib include:

Automating scheduled file uploads to legacy FTP servers
Downloading archives or data feeds from public FTP mirrors
Mirroring remote FTP directories to a local filesystem
Connecting to secure FTP servers using FTP_TLS with an ssl.SSLContext

Real-World Example

The following script downloads all .csv files from a directory on an FTP server:

from ftplib import FTP, all_errors
from pathlib import Path

OUTPUT_DIR = Path("downloads")
OUTPUT_DIR.mkdir(exist_ok=True)

try:
    with FTP("ftp.example.com") as ftp:
        ftp.login()
        ftp.cwd("data/reports")
        csv_files = [name for name in ftp.nlst() if name.endswith(".csv")]
        for filename in csv_files:
            dest = OUTPUT_DIR / filename
            with open(dest, "wb") as f:
                ftp.retrbinary(f"RETR {filename}", f.write)
            print(f"Downloaded: {filename}")
except all_errors as e:
    print(f"FTP error: {e}")

Run it:

$ python ftp_download_csv.py
Downloaded: sales_jan.csv
Downloaded: sales_feb.csv
Downloaded: summary.csv

The script uses nlst() to filter filenames by extension and retrbinary() to download each file into a local downloads/ directory. Wrapping the session in all_errors catches any connection, authentication, or protocol failure in one place.

Tutorial

Python's urllib.request for HTTP Requests

In this tutorial, you'll be making HTTP requests with Python's built-in urllib.request. You'll try out examples and review common errors encountered, all while learning more about HTTP requests and Python in general.

intermediate api web-dev web-scraping

For additional information on related topics, take a look at the following resources: