Update SSL certs

check_ssl.py

import os.path
import ssl
import sys
import urlparse
import urllib


def check_ssl(hostname, port=443):
    '''Check that an SSL certificate is valid

    Uses the Mozilla CA file cached by the cURL project
    '''

    cafile_local = 'cacert.pem'
    cafile_remote = 'http://curl.haxx.se/ca/cacert.pem'
    if not os.path.isfile(cafile_local):
        print >> sys.stderr, "Downloading %s from %s" % (
            cafile_local, cafile_remote)
    urllib.urlretrieve(cafile_remote, cafile_local)

    print >> sys.stderr, "Validating SSL cert at %s:%d" % (
        hostname, port)

    try:
        ssl.get_server_certificate((hostname, port),
            ca_certs=cafile_local)
    except ssl.SSLError:
        print >> sys.stderr, "SSL cert at %s:%d is invalid!" % (
            hostname, port)
        raise


class CheckedSSLUrlOpener(urllib.FancyURLopener):
    '''A URL opener that checks that SSL certificates are valid

    On SSL error, it will raise ssl.
    '''

    def open(self, fullurl, data=None):
        urlbits = urlparse.urlparse(fullurl)
        if urlbits.scheme == 'https':
            if ':' in urlbits.netloc:
                hostname, port = urlbits.netloc.split(':')
            else:
                hostname = urlbits.netloc
                if urlbits.port is None:
                    port = 443
                else:
                    port = urlbits.port
            check_ssl(hostname, port)
        return urllib.FancyURLopener.open(self, fullurl, data)

# Plain usage - can probably do once per day
check_ssl('graph.facebook.com')
check_ssl('www.facebook.com')