Download latest FTP file (sync) using Python example with nlst mlsd or mdtm support

download_latest_ftp_file.md

import ftplib
import glob
import os

DOWNLOADED_FILES_LOCAL_FOLDER = "downloaded_files/"

def connect(): 
    ftp_client = ftplib.FTP()
    ftp_client.connect('test.rebex.net', 21)
    ftp_client.login('demo','password')
    return ftp_client


def find_last_downloaded_file_name():
    list_of_downloaded_files = glob.glob(DOWNLOADED_FILES_LOCAL_FOLDER + "/*")
    latest_downloaded_file = max(list_of_downloaded_files, key=os.path.getmtime)
    file_name = os.path.basename(latest_downloaded_file)
    return file_name


def fetch_latest_ftp_file(ftp_client):
    #1. if FTP server supports nlst -t command
    file_names = ftp_client.nlst("-t")
    lines = ftp_client.nlst("-t")
    latest_ftp_file = lines[-1]
    
    #2. if FTP Server supports MLSD command
    # entries = list(ftp_client.mlsd())
    # entries.sort(key = lambda entry: entry[1]['modify'], reverse = True)
    # latest_ftp_file = entries[0][0]
    # print(latest_ftp_file)

    #3. if FTP Server supports MDTM command
    # latest_time = None
    # latest_name = None
    # for file_name in file_names:
    #     print("Getting time from file "+ file_name)
    #     remote_time = ftp_client.voidcmd("MDTM " + file_name)
    #     if (latest_time is None) or (remote_time > latest_time):
    #         latest_name = file_name
    #         latest_time = remote_time

    return latest_ftp_file
    

def save_file_from_ftp(ftp_file_name, ftp_client):
    file = open(DOWNLOADED_FILES_FOLDER+ftp_file_name, 'wb')
    print(ftp_file_name, " is downloading...")
    ftp_client.retrbinary('RETR ' + ftp_file_name, file.write)


ftp_client = connect()
latest_downloaded_file = find_last_downloaded_file_name()
latest_ftp_file = fetch_latest_ftp_file(ftp_client)

if (latest_ftp_file == latest_downloaded_file):
    print("There is no new file to download")
else:
    save_file_from_ftp(latest_ftp_file, ftp_client)