kumistatus/ssltools/__init__.py

import datetime, OpenSSL, socket, ssl

PEM = 0
DER = 1
DERBIN = 2

def getRemoteCert(host, port, form = PEM):
 context = ssl.SSLContext(ssl.PROTOCOL_TLSv1)
 sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
 sock.settimeout(1)
 wrappedSocket = context.wrap_socket(sock, server_hostname=host)
 try:
  wrappedSocket.connect((host, port))
 except:
  return False
 else:
  if form == PEM:
   response = ssl.DER_cert_to_PEM_cert(wrappedSocket.getpeercert(True))
  elif form == DER:
   response = wrappedSocket.getpeercert(False)
  elif form == DERBIN:
   response = wrappedSocket.getpeercert(True)
  wrappedSocket.close() 
 return response

def getRemoteExpiry(host,port):
 try:
  return datetime.datetime.strptime(str(OpenSSL.crypto.load_certificate(OpenSSL.crypto.FILETYPE_PEM, getRemoteCert(host, port)).get_notAfter().decode("UTF-8")), "%Y%m%d%H%M%SZ")
 except:
  pass