CasperSecurity
<?php
namespace React\Dns\Query;
use React\Promise\Promise;
/**
* Send DNS queries over a UDP or TCP/IP stream transport.
*
* This class will automatically choose the correct transport protocol to send
* a DNS query to your DNS server. It will always try to send it over the more
* efficient UDP transport first. If this query yields a size related issue
* (truncated messages), it will retry over a streaming TCP/IP transport.
*
* For more advanced usages one can utilize this class directly.
* The following example looks up the `IPv6` address for `reactphp.org`.
*
* ```php
* $executor = new SelectiveTransportExecutor($udpExecutor, $tcpExecutor);
*
* $executor->query(
* new Query($name, Message::TYPE_AAAA, Message::CLASS_IN)
* )->then(function (Message $message) {
* foreach ($message->answers as $answer) {
* echo 'IPv6: ' . $answer->data . PHP_EOL;
* }
* }, 'printf');
* ```
*
* Note that this executor only implements the logic to select the correct
* transport for the given DNS query. Implementing the correct transport logic,
* implementing timeouts and any retry logic is left up to the given executors,
* see also [`UdpTransportExecutor`](#udptransportexecutor) and
* [`TcpTransportExecutor`](#tcptransportexecutor) for more details.
*
* Note that this executor is entirely async and as such allows you to execute
* any number of queries concurrently. You should probably limit the number of
* concurrent queries in your application or you're very likely going to face
* rate limitations and bans on the resolver end. For many common applications,
* you may want to avoid sending the same query multiple times when the first
* one is still pending, so you will likely want to use this in combination with
* a `CoopExecutor` like this:
*
* ```php
* $executor = new CoopExecutor(
* new SelectiveTransportExecutor(
* $datagramExecutor,
* $streamExecutor
* )
* );
* ```
*/
class SelectiveTransportExecutor implements ExecutorInterface
{
private $datagramExecutor;
private $streamExecutor;
public function __construct(ExecutorInterface $datagramExecutor, ExecutorInterface $streamExecutor)
{
$this->datagramExecutor = $datagramExecutor;
$this->streamExecutor = $streamExecutor;
}
public function query(Query $query)
{
$stream = $this->streamExecutor;
$pending = $this->datagramExecutor->query($query);
return new Promise(function ($resolve, $reject) use (&$pending, $stream, $query) {
$pending->then(
$resolve,
function ($e) use (&$pending, $stream, $query, $resolve, $reject) {
if ($e->getCode() === (\defined('SOCKET_EMSGSIZE') ? \SOCKET_EMSGSIZE : 90)) {
$pending = $stream->query($query)->then($resolve, $reject);
} else {
$reject($e);
}
}
);
}, function () use (&$pending) {
$pending->cancel();
$pending = null;
});
}
}