Certificate check

check_cert.py

from cryptography import x509
from cryptography.hazmat.backends import default_backend
import socket
import ssl
from datetime import datetime

HOST = 'www.rabobank.nl'

def check_cert(host):
    context = ssl.create_default_context()
    with socket.create_connection((host, 443)) as sock:
        with context.wrap_socket(sock, server_hostname=HOST) as sslsock:
            der_cert = sslsock.getpeercert(True)
      
    cert = x509.load_der_x509_certificate(der_cert, default_backend())        
    print("Certificate will expire on ", datetime.strftime(cert.not_valid_after, '%Y-%m-%d %H:%M:%S'))
    
check_cert(HOST)