Olson timezone retriever

olsongrabber.py

# olsongrabber.py - Olson timezone retriever
# Grabs the latest timezone information from the IANA and concatenates files together
# for use with Moodle, see:
# https://docs.moodle.org/dev/index.php?title=Timezone_information

import os
import shutil
from ftplib import FTP
import tarfile

filename = '';
foldertarget = 'temp';

def mahfilename(line):
	global filename
	if (len(filename) == 0):
		tokens = line.split(' ')
		filename = tokens[-1]


# connect to the IANA's ftp server
ianaftp = FTP('ftp.iana.org')
ianaftp.login()
ianaftp.cwd('/tz/releases/')

# identify the newest data file
ianaftp.retrlines('LIST -t tzdata*.tar.gz', mahfilename)
filename_data = filename;
filebasename_data = os.path.splitext(os.path.splitext(filename)[0])[0]
filename_out = '%s-concatenated.txt' % filebasename_data;

# kill existing local files
if (os.path.exists(filename_out)):
	os.remove(filename_out)
if (os.path.exists(filename_data)):
	os.remove(filename_data)

# grab the latest timezone data release
print ('Latest tz database file: %s' % filebasename_data)

ianaftp.retrbinary('RETR %s' % filename, open(filename, 'wb').write)

# leave the IANA's server
ianaftp.quit()

# untar the file
if (os.path.exists(foldertarget)):
	shutil.rmtree(foldertarget)
os.mkdir(foldertarget)

dfnfile = tarfile.open(filename_data, mode='r:gz')
dfnfile.extractall(foldertarget)

# concatenate the source files
sources = ['africa', 'antarctica', 'asia', 'australasia', 'europe', 'northamerica', 'southamerica', 'etcetera']
with open(filename_out, 'w') as outfile:
	for source in sources:
		with open('%s/%s' % (foldertarget, source)) as infile:
			for line in infile:
				outfile.write(line)

# clean up afterwards
os.remove(filename_data)
shutil.rmtree(foldertarget)