How to Validate SSL Certificates for Multiple Domains in Python

import ssl
import socket
from datetime import datetime

def check_ssl_certificate(hostname: str, port: int = 443) -> dict:
    """Validate SSL certificate for a given hostname."""
    context = ssl.create_default_context()
    with socket.create_connection((hostname, port), timeout=5) as sock:
        with context.wrap_socket(sock, server_hostname=hostname) as ssock:
            cert = ssock.getpeercert()
    
    expiry_date = datetime.strptime(cert['notAfter'], '%b %d %H:%M:%S %Y %Z')
    days_remaining = (expiry_date - datetime.now()).days
    
    return {
        'hostname': hostname,
        'expires': expiry_date.strftime('%Y-%m-%d'),
        'days_remaining': days_remaining,
        'valid': days_remaining > 0,
        'issuer': dict(cert['issuer'][0][0]),
        'subject': dict(cert['subject'][0][0])
    }

def validate_domains(domains: list) -> list:
    """Validate certificates for multiple domains."""
    results = []
    for domain in domains:
        try:
            result = check_ssl_certificate(domain)
        except Exception as e:
            result = {'hostname': domain, 'error': str(e), 'valid': False}
        results.append(result)
    return results

if __name__ == "__main__":
    test_domains = ['example.com', 'google.com', 'nonexistent.domain']
    ssl_results = validate_domains(test_domains)
    for result in ssl_results:
        status = "✓" if result.get('valid', False) else "✗"
        print(f"{status} {result['hostname']}: "
              f"expires {result.get('expires', 'N/A')} "
              f"({result.get('days_remaining', 'N/A')} days)")