如何在PHP中检查主机名是否与SSL证书中的通用名称匹配？

$cert = file_get_contents('/path/to/certificate.crt');
$certData = openssl_x509_parse($cert);
$commonName = $certData['subject']['CN'];

$hostname = gethostname();

if (strcasecmp($hostname, $commonName) === 0) {
    echo "主机名与SSL证书通用名称匹配";
} else {
    echo "主机名与SSL证书通用名称不匹配";
}