work

#!/usr/bin/env python

import sys
import getpass
from os import path

def exit_error(error):
    print(error, file=sys.stderr)
    exit(1)

hosts_file  = '/etc/hosts'

# since this script must be run as root, we simply hardcode the ini_local to
# the home directory of current user.
ini_local   = '/home/USERNAME/.config/sites.conf'
ini_global  = '/etc/sites.conf'

start_token = '## start-gsd'
end_token   = '## end-gsd'

def ini_to_array(ini_file):
    # One site per line, because this is more readable, and easy to add new
    # sites in the middle, which helps keeping the config file organized.
    # Allow comments starting with '#'.
    sites = []
    if path.exists(ini_file):
        with open(ini_file) as f:
            for line in f:
                line = line.strip()
                # omit blank/comment line
                if len(line) == 0 or line[0] == '#': continue

                site = line.split('#')[0].strip()

                # simple sanity check
                # url like a.bc is at least 4 characters long, and the rightmost
                # '.' should be somewhere in site[1:-2]
                if len(site) >= 4 and 0 < site.rfind('.') < len(site)-2:
                    sites.append(site)
                else:
                    print(site, 'is not a valid url.', file=sys.stderr)
    else:
        print('WARNING:', ini_file, 'does not exist.', file=sys.stderr)
    return sites

def work():
    # FIXME if opened in other mode, 'contents' will be empty, so add redundant
    # check here.
    testFile = open(hosts_file, 'r')
    contents = testFile.read()
    if start_token in contents and end_token in contents:
        testFile.close()
        exit_error("Work mode already set.")

    hFile = open(hosts_file, 'a+')

    site_list = ini_to_array(ini_global) + ini_to_array(ini_local)
    if len(site_list) > 0:
        print(start_token, file=hFile)
        # remove duplicates by converting list to a set
        for site in set(site_list):
            print("127.0.0.1\t" + site, file=hFile)
            print("127.0.0.1\twww." + site, file=hFile)

        print(end_token, file=hFile)
    else:
        print('No sites given, aborted.', file=sys.stderr)
    hFile.close()

def main():
    if getpass.getuser() != 'root':
        exit_error('Please run script as root.')
    work()

if __name__ == "__main__":
    main()