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