verisign ftp download unzip parse zone files

verisign_ftp.py

from ftplib import FTP
import gzip
import re
import os


class ComParser:

    _host = 'rz.verisign-grs.com'
    _file_in = 'com.zone.gz'
    _file_out = 'com.zone.txt'
    _file_parsed = 'com.zone.parsed'
    _file_parsed_old = 'com.zone.parsed.old'
    _file_new_domains = 'com.zone.parsed.newdomains'
    _login = ''
    _passwd = ''

    def __init__(self):
        self.ftp = FTP(self._host)

    def login(self):
        self.ftp.login(user=self._login, passwd=self._passwd)

    def download(self):
        file = open(self._file_in, 'wb')
        self.ftp.retrbinary('RETR %s' % self._file_in, file.write)
        file.close()

    def unzip(self):
        f_in = gzip.open(self._file_in)
        f_out = open(self._file_out, 'wb')
        for l in f_in:
            f_out.write(l)

    def parse(self):
        input_file = open(self._file_out, 'r')
        output_file = open(self._file_parsed, 'w+')
        previous = None
        for line in input_file:
            match = re.search('^([A-Z0-9-]+) NS', line)
            if match:
                domain = match.group(1).lower()
                if domain != previous:
                    domain_str = 'http://%s.com\n' % domain
                    output_file.writelines(domain_str)
                    previous = domain

    def rename(self):
        os.rename(self._file_parsed, self._file_parsed_old)


if __name__ == '__main__':
    parser = ComParser()
    parser.login()
    parser.download()
    parser.unzip()
    parser.parse()