certificate.py

certificate.py

from datetime import datetime
from OpenSSL import crypto
from pytz import timezone
import ssl


class CetificateDatetime:
  WEEKDAYS = ('月', '火', '水', '木', '金', '土', '日')

  def __init__(self, dt):
    dt = dt.astimezone(timezone('UTC'))
    dt = dt.astimezone(timezone('Asia/Tokyo'))
    self.dt = dt

  def __repr__(self):
    date = self.dt.strftime('%Y/%m/%d')
    wday = self.WEEKDAYS[self.dt.weekday()]
    time = self.dt.strftime('%H:%M:%S %Z')

    return f'{date} ({wday}) {time}'


class Cetificate:
  datetime_format = '%Y%m%d%H%M%SZ'

  def __init__(self, hostname):
    self.hostname = hostname

  @property
  def x509(self):
    if not hasattr(self, '_x509'):
      cert = ssl.get_server_certificate((self.hostname, 443))
      self._x509 = crypto.load_certificate(crypto.FILETYPE_PEM, cert)

    return self._x509

  @property
  def not_before(self):
    dt = datetime.strptime(self.x509.get_notBefore().decode(),
                           self.datetime_format)
    dt = self._utc_to_jst(dt)

    return CetificateDatetime(dt)

  @property
  def not_after(self):
    dt = datetime.strptime(self.x509.get_notAfter().decode(),
                           self.datetime_format)
    dt = self._utc_to_jst(dt)

    return CetificateDatetime(dt)

  @property
  def cn(self):
    return self.x509.get_issuer().CN

  @property
  def issuer(self):
    return self.x509.get_issuer().CN

  def _utc_to_jst(self, dt):
    dt = dt.astimezone(timezone('UTC'))
    dt = dt.astimezone(timezone('Asia/Tokyo'))

    return dt


if __name__ == '__main__':
  cert = Cetificate('letsencrypt.jp')

  print(f'コモンネーム: {cert.cn}')
  print(f'発行者: {cert.issuer}')
  print(f'Not Before: {cert.not_before}')
  print(f'Not After: {cert.not_after}')