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<?php
namespace React\Dns\Resolver;
use React\Dns\Model\Message;
use React\Dns\Query\ExecutorInterface;
use React\Dns\Query\Query;
use React\Dns\RecordNotFoundException;
/**
* @see ResolverInterface for the base interface
*/
final class Resolver implements ResolverInterface
{
private $executor;
public function __construct(ExecutorInterface $executor)
{
$this->executor = $executor;
}
public function resolve($domain)
{
return $this->resolveAll($domain, Message::TYPE_A)->then(function (array $ips) {
return $ips[array_rand($ips)];
});
}
public function resolveAll($domain, $type)
{
$query = new Query($domain, $type, Message::CLASS_IN);
$that = $this;
return $this->executor->query(
$query
)->then(function (Message $response) use ($query, $that) {
return $that->extractValues($query, $response);
});
}
/**
* [Internal] extract all resource record values from response for this query
*
* @param Query $query
* @param Message $response
* @return array
* @throws RecordNotFoundException when response indicates an error or contains no data
* @internal
*/
public function extractValues(Query $query, Message $response)
{
// reject if response code indicates this is an error response message
$code = $response->rcode;
if ($code !== Message::RCODE_OK) {
switch ($code) {
case Message::RCODE_FORMAT_ERROR:
$message = 'Format Error';
break;
case Message::RCODE_SERVER_FAILURE:
$message = 'Server Failure';
break;
case Message::RCODE_NAME_ERROR:
$message = 'Non-Existent Domain / NXDOMAIN';
break;
case Message::RCODE_NOT_IMPLEMENTED:
$message = 'Not Implemented';
break;
case Message::RCODE_REFUSED:
$message = 'Refused';
break;
default:
$message = 'Unknown error response code ' . $code;
}
throw new RecordNotFoundException(
'DNS query for ' . $query->describe() . ' returned an error response (' . $message . ')',
$code
);
}
$answers = $response->answers;
$addresses = $this->valuesByNameAndType($answers, $query->name, $query->type);
// reject if we did not receive a valid answer (domain is valid, but no record for this type could be found)
if (0 === count($addresses)) {
throw new RecordNotFoundException(
'DNS query for ' . $query->describe() . ' did not return a valid answer (NOERROR / NODATA)'
);
}
return array_values($addresses);
}
/**
* @param \React\Dns\Model\Record[] $answers
* @param string $name
* @param int $type
* @return array
*/
private function valuesByNameAndType(array $answers, $name, $type)
{
// return all record values for this name and type (if any)
$named = $this->filterByName($answers, $name);
$records = $this->filterByType($named, $type);
if ($records) {
return $this->mapRecordData($records);
}
// no matching records found? check if there are any matching CNAMEs instead
$cnameRecords = $this->filterByType($named, Message::TYPE_CNAME);
if ($cnameRecords) {
$cnames = $this->mapRecordData($cnameRecords);
foreach ($cnames as $cname) {
$records = array_merge(
$records,
$this->valuesByNameAndType($answers, $cname, $type)
);
}
}
return $records;
}
private function filterByName(array $answers, $name)
{
return $this->filterByField($answers, 'name', $name);
}
private function filterByType(array $answers, $type)
{
return $this->filterByField($answers, 'type', $type);
}
private function filterByField(array $answers, $field, $value)
{
$value = strtolower($value);
return array_filter($answers, function ($answer) use ($field, $value) {
return $value === strtolower($answer->$field);
});
}
private function mapRecordData(array $records)
{
return array_map(function ($record) {
return $record->data;
}, $records);
}
}
|
