Yiisoft\NetworkUtilities\DnsHelper

Complexity

Total Complexity

5

Size/Duplication

Total Lines	64
Duplicated Lines	0 %

Test Coverage

Coverage

100%

Importance

Changes	4
Bugs	0	Features	0

3 Methods

Rating	Name	Duplication	Size	Complexity
A	acceptsEmails()	0	6	3
A	existsMx()	0	15	1
A	existsA()	0	14	1

<?php

declare(strict_types=1);

namespace Yiisoft\NetworkUtilities;

use RuntimeException;

/**
 * DnsHelper contains static methods to work with DNS.
 */
final class DnsHelper
{
    /**
     * Checks DNS MX record availability.
     *
     * @param string $hostname Hostname without dot at end.
     *
     * @return bool Whether MX record exists.
     */
    public static function existsMx(string $hostname): bool
    {
        set_error_handler(static function (int $errorNumber, string $errorString) use ($hostname): bool {
            throw new RuntimeException(
                sprintf('Failed to get DNS record "%s". ', $hostname) . $errorString,
                $errorNumber
            );
        });

        $hostname = rtrim($hostname, '.') . '.';
        $result = dns_get_record($hostname, DNS_MX);

        restore_error_handler();

        return count($result) > 0;
    }

    /**
     * Checks DNS A record availability.
     *
     * @param string $hostname Hostname without dot at end.
     *
     * @return bool Whether A records exists.
     */
    public static function existsA(string $hostname): bool
    {
        set_error_handler(static function (int $errorNumber, string $errorString) use ($hostname): bool {
            throw new RuntimeException(
                sprintf('Failed to get DNS record "%s". ', $hostname) . $errorString,
                $errorNumber
            );
        });

        $result = dns_get_record($hostname, DNS_A);

        restore_error_handler();

        return count($result) > 0;
    }

    /**
     * Checks email's domain availability.
     *
     * @link https://tools.ietf.org/html/rfc5321#section-5
     *
     * @param string $hostnameOrEmail Hostname without dot at end or an email.
     *
     * @return bool Whether email domain is available.
     */
    public static function acceptsEmails(string $hostnameOrEmail): bool
    {
        if (strpos($hostnameOrEmail, '@') !== false) {
            [, $hostnameOrEmail] = explode('@', $hostnameOrEmail, 2);
        }
        return self::existsMx($hostnameOrEmail) || self::existsA($hostnameOrEmail);
    }
}