Python Download Latest CSV from FTP server [duplicate] - python-3.x

Question

I am using ftplib to connect to an ftp site. I want to get the most recently uploaded file and download it. I am able to connect to the ftp server and list the files, I also have put them in a list and got the datefield converted. Is there any function/module which can get the recent date and output the whole line from the list?
#!/usr/bin/env python
import ftplib
import os
import socket
import sys
HOST = 'test'
def main():
try:
f = ftplib.FTP(HOST)
except (socket.error, socket.gaierror), e:
print 'cannot reach to %s' % HOST
return
print "Connect to ftp server"
try:
f.login('anonymous','al#ge.com')
except ftplib.error_perm:
print 'cannot login anonymously'
f.quit()
return
print "logged on to the ftp server"
data = []
f.dir(data.append)
for line in data:
datestr = ' '.join(line.split()[0:2])
orig-date = time.strptime(datestr, '%d-%m-%y %H:%M%p')
f.quit()
return
if __name__ == '__main__':
main()
RESOLVED:
data = []
f.dir(data.append)
datelist = []
filelist = []
for line in data:
col = line.split()
datestr = ' '.join(line.split()[0:2])
date = time.strptime(datestr, '%m-%d-%y %H:%M%p')
datelist.append(date)
filelist.append(col[3])
combo = zip(datelist,filelist)
who = dict(combo)
for key in sorted(who.iterkeys(), reverse=True):
print "%s: %s" % (key,who[key])
filename = who[key]
print "file to download is %s" % filename
try:
f.retrbinary('RETR %s' % filename, open(filename, 'wb').write)
except ftplib.err_perm:
print "Error: cannot read file %s" % filename
os.unlink(filename)
else:
print "***Downloaded*** %s " % filename
return
f.quit()
return
One problem, is it possible to retrieve the first element from the dictionary? what I did here is that the for loop runs only once and exits thereby giving me the first sorted value which is fine, but I don't think it is a good practice to do it in this way..

Answer 1

For those looking for a full solution for finding the latest file in a folder:
MLSD
If your FTP server supports MLSD command, a solution is easy:
entries = list(ftp.mlsd())
entries.sort(key = lambda entry: entry[1]['modify'], reverse = True)
latest_name = entries[0][0]
print(latest_name)
LIST
If you need to rely on an obsolete LIST command, you have to parse a proprietary listing it returns.
Common *nix listing is like:
-rw-r--r-- 1 user group 4467 Mar 27 2018 file1.zip
-rw-r--r-- 1 user group 124529 Jun 18 15:31 file2.zip
With a listing like this, this code will do:
from dateutil import parser
# ...
lines = []
ftp.dir("", lines.append)
latest_time = None
latest_name = None
for line in lines:
tokens = line.split(maxsplit = 9)
time_str = tokens[5] + " " + tokens[6] + " " + tokens[7]
time = parser.parse(time_str)
if (latest_time is None) or (time > latest_time):
latest_name = tokens[8]
latest_time = time
print(latest_name)
This is a rather fragile approach.
MDTM
A more reliable, but a way less efficient, is to use MDTM command to retrieve timestamps of individual files/folders:
names = ftp.nlst()
latest_time = None
latest_name = None
for name in names:
time = ftp.voidcmd("MDTM " + name)
if (latest_time is None) or (time > latest_time):
latest_name = name
latest_time = time
print(latest_name)
For an alternative version of the code, see the answer by #Paulo.
Non-standard -t switch
Some FTP servers support a proprietary non-standard -t switch for NLST (or LIST) command.
lines = ftp.nlst("-t")
latest_name = lines[-1]
See How to get files in FTP folder sorted by modification time.
Downloading found file
No matter what approach you use, once you have the latest_name, you download it as any other file:
with open(latest_name, 'wb') as f:
ftp.retrbinary('RETR '+ latest_name, f.write)
See also
Get the latest FTP folder name in Python
How to get FTP file's modify time using Python ftplib

Answer 2

Why don't you use next dir option?
ftp.dir('-t',data.append)
With this option the file listing is time ordered from newest to oldest. Then just retrieve the first file in the list to download it.

Answer 3

With NLST, like shown in Martin Prikryl's response,
you should use sorted method:
ftp = FTP(host="127.0.0.1", user="u",passwd="p")
ftp.cwd("/data")
file_name = sorted(ftp.nlst(), key=lambda x: ftp.voidcmd(f"MDTM {x}"))[-1]

Answer 4

If you have all the dates in time.struct_time (strptime will give you this) in a list then all you have to do is sort the list.
Here's an example :
#!/usr/bin/python
import time
dates = [
"Jan 16 18:35 2012",
"Aug 16 21:14 2012",
"Dec 05 22:27 2012",
"Jan 22 19:42 2012",
"Jan 24 00:49 2012",
"Dec 15 22:41 2012",
"Dec 13 01:41 2012",
"Dec 24 01:23 2012",
"Jan 21 00:35 2012",
"Jan 16 18:35 2012",
]
def main():
datelist = []
for date in dates:
date = time.strptime(date, '%b %d %H:%M %Y')
datelist.append(date)
print datelist
datelist.sort()
print datelist
if __name__ == '__main__':
main()

Answer 5

I don't know how it's your ftp, but your example was not working for me. I changed some lines related to the date sorting part:
import sys
from ftplib import FTP
import os
import socket
import time
# Connects to the ftp
ftp = FTP(ftpHost)
ftp.login(yourUserName,yourPassword)
data = []
datelist = []
filelist = []
ftp.dir(data.append)
for line in data:
col = line.split()
datestr = ' '.join(line.split()[5:8])
date = time.strptime(datestr, '%b %d %H:%M')
datelist.append(date)
filelist.append(col[8])
combo = zip(datelist,filelist)
who = dict(combo)
for key in sorted(who.iterkeys(), reverse=True):
print "%s: %s" % (key,who[key])
filename = who[key]
print "file to download is %s" % filename
try:
ftp.retrbinary('RETR %s' % filename, open(filename, 'wb').write)
except ftplib.err_perm:
print "Error: cannot read file %s" % filename
os.unlink(filename)
else:
print "***Downloaded*** %s " % filename
ftp.quit()