Initial commit

vendor/egulias/email-validator/src/Validation/DNSCheckValidation.php

@@ -0,0 +1,211 @@
+<?php
+
+namespace Egulias\EmailValidator\Validation;
+
+use Egulias\EmailValidator\EmailLexer;
+use Egulias\EmailValidator\Result\InvalidEmail;
+use Egulias\EmailValidator\Result\Reason\DomainAcceptsNoMail;
+use Egulias\EmailValidator\Result\Reason\LocalOrReservedDomain;
+use Egulias\EmailValidator\Result\Reason\NoDNSRecord as ReasonNoDNSRecord;
+use Egulias\EmailValidator\Result\Reason\UnableToGetDNSRecord;
+use Egulias\EmailValidator\Warning\NoDNSMXRecord;
+use Egulias\EmailValidator\Warning\Warning;
+
+class DNSCheckValidation implements EmailValidation
+{
+
+    /**
+     * Reserved Top Level DNS Names (https://tools.ietf.org/html/rfc2606#section-2),
+     * mDNS and private DNS Namespaces (https://tools.ietf.org/html/rfc6762#appendix-G)
+     * 
+     * @var string[]
+     */
+    public const RESERVED_DNS_TOP_LEVEL_NAMES = [
+        // Reserved Top Level DNS Names
+        'test',
+        'example',
+        'invalid',
+        'localhost',
+
+        // mDNS
+        'local',
+
+        // Private DNS Namespaces
+        'intranet',
+        'internal',
+        'private',
+        'corp',
+        'home',
+        'lan',
+    ];
+
+    /**
+     * @var Warning[]
+     */
+    private $warnings = [];
+
+    /**
+     * @var InvalidEmail|null
+     */
+    private $error;
+
+    /**
+     * @var array
+     */
+    private $mxRecords = [];
+
+    /**
+     * @var DNSGetRecordWrapper
+     */
+    private $dnsGetRecord;
+
+    public function __construct(?DNSGetRecordWrapper $dnsGetRecord = null)
+    {
+        if (!function_exists('idn_to_ascii')) {
+            throw new \LogicException(sprintf('The %s class requires the Intl extension.', __CLASS__));
+        }
+
+        if ($dnsGetRecord == null) {
+            $dnsGetRecord = new DNSGetRecordWrapper();
+        }
+
+        $this->dnsGetRecord = $dnsGetRecord;
+    }
+
+    public function isValid(string $email, EmailLexer $emailLexer): bool
+    {
+        // use the input to check DNS if we cannot extract something similar to a domain
+        $host = $email;
+
+        // Arguable pattern to extract the domain. Not aiming to validate the domain nor the email
+        if (false !== $lastAtPos = strrpos($email, '@')) {
+            $host = substr($email, $lastAtPos + 1);
+        }
+
+        // Get the domain parts
+        $hostParts = explode('.', $host);
+
+        $isLocalDomain = count($hostParts) <= 1;
+        $isReservedTopLevel = in_array($hostParts[(count($hostParts) - 1)], self::RESERVED_DNS_TOP_LEVEL_NAMES, true);
+
+        // Exclude reserved top level DNS names
+        if ($isLocalDomain || $isReservedTopLevel) {
+            $this->error = new InvalidEmail(new LocalOrReservedDomain(), $host);
+            return false;
+        }
+
+        return $this->checkDns($host);
+    }
+
+    public function getError(): ?InvalidEmail
+    {
+        return $this->error;
+    }
+
+    /**
+     * @return Warning[]
+     */
+    public function getWarnings(): array
+    {
+        return $this->warnings;
+    }
+
+    /**
+     * @param string $host
+     *
+     * @return bool
+     */
+    protected function checkDns($host)
+    {
+        $variant = INTL_IDNA_VARIANT_UTS46;
+
+        $host = rtrim(idn_to_ascii($host, IDNA_DEFAULT, $variant), '.');
+
+        $hostParts = explode('.', $host);
+        $host = array_pop($hostParts);
+
+        while (count($hostParts) > 0) {
+            $host = array_pop($hostParts) . '.' . $host;
+
+            if ($this->validateDnsRecords($host)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+
+    /**
+     * Validate the DNS records for given host.
+     *
+     * @param string $host A set of DNS records in the format returned by dns_get_record.
+     *
+     * @return bool True on success.
+     */
+    private function validateDnsRecords($host): bool
+    {
+        $dnsRecordsResult = $this->dnsGetRecord->getRecords($host, DNS_A + DNS_MX);
+
+        if ($dnsRecordsResult->withError()) {
+            $this->error = new InvalidEmail(new UnableToGetDNSRecord(), '');
+            return false;
+        }
+
+        $dnsRecords = $dnsRecordsResult->getRecords();
+
+        // Combined check for A+MX+AAAA can fail with SERVFAIL, even in the presence of valid A/MX records
+        $aaaaRecordsResult = $this->dnsGetRecord->getRecords($host, DNS_AAAA);
+
+        if (! $aaaaRecordsResult->withError()) {
+            $dnsRecords = array_merge($dnsRecords, $aaaaRecordsResult->getRecords());
+        }
+
+        // No MX, A or AAAA DNS records
+        if ($dnsRecords === []) {
+            $this->error = new InvalidEmail(new ReasonNoDNSRecord(), '');
+            return false;
+        }
+
+        // For each DNS record
+        foreach ($dnsRecords as $dnsRecord) {
+            if (!$this->validateMXRecord($dnsRecord)) {
+                // No MX records (fallback to A or AAAA records)
+                if (empty($this->mxRecords)) {
+                    $this->warnings[NoDNSMXRecord::CODE] = new NoDNSMXRecord();
+                }
+                return false;
+            }
+        }
+        return true;
+    }
+
+    /**
+     * Validate an MX record
+     *
+     * @param array $dnsRecord Given DNS record.
+     *
+     * @return bool True if valid.
+     */
+    private function validateMxRecord($dnsRecord): bool
+    {
+        if (!isset($dnsRecord['type'])) {
+            $this->error = new InvalidEmail(new ReasonNoDNSRecord(), '');
+            return false;
+        }
+
+        if ($dnsRecord['type'] !== 'MX') {
+            return true;
+        }
+
+        // "Null MX" record indicates the domain accepts no mail (https://tools.ietf.org/html/rfc7505)
+        if (empty($dnsRecord['target']) || $dnsRecord['target'] === '.') {
+            $this->error = new InvalidEmail(new DomainAcceptsNoMail(), "");
+            return false;
+        }
+
+        $this->mxRecords[] = $dnsRecord;
+
+        return true;
+    }
+}