the following is a script which downloads the latest image from one of the NASA ftp server at eol.jsc.nasa.gov and to my amazement there are new images every 5 mins!, so I sent python to grab that image….
python supports ftp by importing the ftplib module and ftplib.FTP class.
connecting to an ftp server is very straightforward…
1 2 3 4 5 | >>>from ftplib import FTP >>>f = FTP('my ftp server ') >>>f.login('anonymous', 'your@email.address') : >>>f.quit() |
The core job inside in this script is to first dump the listing of files into a list, then reading that list line by line, split the date and convert it to a datetime object and store it in a new list, also i created another list which stores the filenames, next i combined these two lists to form a dictionary, and sorted the dictionary using the KEY(datetime object) in reverse order, and ran the loop only once as i need only the first image.
here is the full script..
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 | #!/usr/bin/env python import ftplib import os import socket import sys import time import datetime HOST = 'eol.jsc.nasa.gov' 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','alpha@krisindigitalage.com') except ftplib.error_perm: print 'cannot login anonymously' f.quit() return print "logged on to the ftp server" 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]) combined = zip(datelist,filelist) new_dict = dict(combined) # print who # for key,value in sorted(new_dict.iteritems(), key =lambda (k,v): (v,k)): for key in sorted(who.iterkeys(), reverse=True): print "%s: %s" % (key,new_dict[key]) filename = new_dict[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 if __name__ == '__main__': main() |
