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WyriHaximusWyriHaximus
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Implement the Happy Eye Balls RFC's
By using the happy eye balls algorythm as descripted in RFC6555 and RFC8305 it will connect to the quickest responding server with a preference for IPv6.
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‎README.md

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@@ -43,6 +43,7 @@ handle multiple concurrent connections without blocking.
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* [Connector](#connector)
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* [Advanced client usage](#advanced-client-usage)
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* [TcpConnector](#tcpconnector)
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* [HappyEyeBallsConnector](#happyeyeballsconnector)
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* [DnsConnector](#dnsconnector)
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* [SecureConnector](#secureconnector)
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* [TimeoutConnector](#timeoutconnector)
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This is used by the `SecureConnector` and `DnsConnector` to verify the peer
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name and can also be used if you want a custom TLS peer name.
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#### HappyEyeBallsConnector
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The `HappyEyeBallsConnector` class implements the
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[`ConnectorInterface`](#connectorinterface) and allows you to create plaintext
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TCP/IP connections to any hostname-port-combination. Internally it implements the
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happy eyeballs algorythm from [`RFC6555`](https://tools.ietf.org/html/rfc6555) and
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[`RFC8305`](https://tools.ietf.org/html/rfc8305) to support IPv6 and IPv4 hostnames.
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It does so by decorating a given `TcpConnector` instance so that it first
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looks up the given domain name via DNS (if applicable) and then establishes the
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underlying TCP/IP connection to the resolved target IP address.
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Make sure to set up your DNS resolver and underlying TCP connector like this:
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```php
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$dnsResolverFactory = new React\Dns\Resolver\Factory();
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$dns = $dnsResolverFactory->createCached('8.8.8.8', $loop);
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$dnsConnector = new React\Socket\HappyEyeBallsConnector($loop, $tcpConnector, $dns);
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$dnsConnector->connect('www.google.com:80')->then(function (React\Socket\ConnectionInterface $connection) {
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$connection->write('...');
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$connection->end();
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});
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$loop->run();
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```
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See also the [examples](examples).
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Pending connection attempts can be cancelled by cancelling its pending promise like so:
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```php
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$promise = $dnsConnector->connect('www.google.com:80');
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$promise->cancel();
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```
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Calling `cancel()` on a pending promise will cancel the underlying DNS lookups
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and/or the underlying TCP/IP connection(s) and reject the resulting promise.
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> Advanced usage: Internally, the `HappyEyeBallsConnector` relies on a `Resolver` to
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look up the IP addresses for the given hostname.
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It will then replace the hostname in the destination URI with this IP's and
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append a `hostname` query parameter and pass this updated URI to the underlying
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connector.
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The Happy Eye Balls algorythm describes looking the IPv6 and IPv4 address for
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the given hostname so this connector sends out two DNS lookups for the A and
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AAAA records. It then uses all IP addresses (both v6 and v4) and tries to
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connect to all of them with a 50ms interval in between. Alterating between IPv6
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and IPv4 addresses. When a connection is established all the other DNS lookups
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and connection attempts are cancelled.
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#### DnsConnector
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The `DnsConnector` class implements the

‎src/HappyEyeBallsConnector.php

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<?php
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namespace React\Socket;
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use React\Dns\Model\Message;
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use React\Dns\Resolver\Resolver;
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use React\EventLoop\LoopInterface;
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use React\EventLoop\TimerInterface;
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use React\Promise;
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use React\Promise\CancellablePromiseInterface;
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use InvalidArgumentException;
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use RuntimeException;
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final class HappyEyeBallsConnector implements ConnectorInterface
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{
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private $loop;
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private $connector;
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private $resolver;
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public function __construct(LoopInterface $loop, ConnectorInterface $connector, Resolver $resolver)
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{
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$this->loop = $loop;
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$this->connector = $connector;
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$this->resolver = $resolver;
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}
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public function connect($uri)
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{
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if (\strpos($uri, '://') === false) {
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$parts = \parse_url('tcp://' . $uri);
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unset($parts['scheme']);
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} else {
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$parts = \parse_url($uri);
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}
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if (!$parts || !isset($parts['host'])) {
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return Promise\reject(new \InvalidArgumentException('Given URI "' . $uri . '" is invalid'));
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}
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$host = \trim($parts['host'], '[]');
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$connector = $this->connector;
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// skip DNS lookup / URI manipulation if this URI already contains an IP
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if (false !== \filter_var($host, \FILTER_VALIDATE_IP)) {
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return $connector->connect($uri);
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}
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$that = $this;
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$loop = $this->loop;
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$resolver = $this->resolver;
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$resolved = array();
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$resolverPromises = array();
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$connectionPromises = array();
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$timer = null;
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return new Promise\Promise(function ($resolve, $reject) use (&$timer, &$resolverPromises, &$connectionPromises, &$resolved, $loop, $resolver, $uri, $parts, $host, $that) {
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$connectQueue = array();
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$ipsCount = 0;
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$failureCount = 0;
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$check = function () use (&$timer, &$resolved, &$connectQueue, &$failureCount, &$ipsCount, &$connectionPromises, &$resolverPromises, $loop, $uri, $parts, $host, $that, $resolve, $reject, &$check) {
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$hasBeenResolved = true;
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foreach ($resolved as $typeHasBeenResolved) {
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if ($typeHasBeenResolved === false) {
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$hasBeenResolved = false;
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break;
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}
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}
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if ($hasBeenResolved === true && \count($connectQueue) === 0 && $timer instanceof TimerInterface) {
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$loop->cancelTimer($timer);
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$timer = null;
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return;
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}
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if (\count($connectQueue) === 0 && $timer instanceof TimerInterface) {
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$loop->cancelTimer($timer);
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$timer = null;
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return;
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}
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$ip = \array_shift($connectQueue);
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if (\count($connectQueue) === 0 && $timer instanceof TimerInterface) {
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$loop->cancelTimer($timer);
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$timer = null;
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}
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$connectionPromises[$ip] = $that->attemptConnection($ip, $uri, $parts, $host)->then(function ($connection) use ($resolve, &$connectionPromises, &$resolverPromises, $ip, &$timer, $loop) {
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unset($connectionPromises[$ip]);
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/** @var CancellablePromiseInterface $promise */
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foreach ($connectionPromises as $connectionPromise) {
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if (!($connectionPromise instanceof CancellablePromiseInterface)) {
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continue;
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}
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$connectionPromise->cancel();
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$connectionPromise = null;
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}
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/** @var CancellablePromiseInterface $promise */
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foreach ($resolverPromises as $resolverPromise) {
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if (!($resolverPromise instanceof CancellablePromiseInterface)) {
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continue;
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}
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$resolverPromise->cancel();
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$resolverPromise = null;
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}
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if ($timer instanceof TimerInterface) {
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$loop->cancelTimer($timer);
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$timer = null;
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}
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$resolve($connection);
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}, function () use (&$failureCount, &$ipsCount, &$resolved, $reject, $loop, &$timer, $host, &$connectionPromises, $ip) {
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unset($connectionPromises[$ip]);
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$failureCount++;
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foreach ($resolved as $typeHasBeenResolved) {
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if ($typeHasBeenResolved === false) {
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return;
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}
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}
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if ($ipsCount === $failureCount) {
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if ($timer instanceof TimerInterface) {
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$loop->cancelTimer($timer);
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$timer = null;
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}
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$reject(new \RuntimeException('All attempts to connect to "' . $host . '" have failed'));
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}
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});
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if (\count($connectQueue) > 0 && $timer === null) {
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$timer = $loop->addPeriodicTimer(0.05, $check);
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}
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};
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foreach (array(Message::TYPE_AAAA, Message::TYPE_A) as $type) {
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$resolved[$type] = false;
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$resolverPromises[$type] = $resolver->resolveAll($host, $type)->then(function (array $ips) use (&$connectQueue, &$resolved, $type, $check, &$ipsCount, &$resolverPromises, &$timer) {
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unset($resolverPromises[$type]);
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$resolved[$type] = true;
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$ipsCount += \count($ips);
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$connectQueueStash = $connectQueue;
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$connectQueue = array();
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while (\count($connectQueueStash) > 0 || \count($ips) > 0) {
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if (\count($ips) > 0) {
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$connectQueue[] = \array_shift($ips);
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}
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if (\count($connectQueueStash) > 0) {
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$connectQueue[] = \array_shift($connectQueueStash);
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}
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}
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$check();
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}, function () use (&$resolved, $type, &$resolverPromises, &$ipsCount, $reject, $uri) {
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unset($resolverPromises[$type]);
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$resolved[$type] = true;
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foreach ($resolved as $typeHasBeenResolved) {
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if ($typeHasBeenResolved === false) {
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return;
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}
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}
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if ($ipsCount === 0) {
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unset($resolverPromises, $resolved);
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$reject(new \RuntimeException('Connection to ' . $uri . ' failed during DNS lookup: DNS error'));
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$reject = null;
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}
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});
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}
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}, function ($_, $reject) use (&$resolverPromises, &$connectionPromises, &$timer, &$resolved, $loop, $uri) {
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if ($timer instanceof TimerInterface) {
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$loop->cancelTimer($timer);
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$timer = null;
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}
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foreach ($resolverPromises as $resolverPromise) {
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if ($resolverPromise instanceof CancellablePromiseInterface) {
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$resolverPromise->cancel();
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$resolverPromise = null;
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}
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}
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$resolverPromises = null;
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foreach ($connectionPromises as $connectionPromise) {
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if ($connectionPromise instanceof CancellablePromiseInterface) {
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$connectionPromise->cancel();
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$connectionPromise = null;
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}
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}
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$connectionPromises = null;
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foreach ($resolved as $typeHasBeenResolved) {
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if ($typeHasBeenResolved === true) {
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return;
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}
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}
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$reject(new \RuntimeException('Connection to ' . $uri . ' cancelled during DNS lookup'));
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$_ = $reject = null;
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});
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}
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/**
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* @internal
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*/
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public function attemptConnection($ip, $uri, $parts, $host)
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{
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$connector = $this->connector;
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$resolved = null;
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$promise = null;
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return new Promise\Promise(
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function ($resolve, $reject) use (&$promise, &$resolved, $ip, $uri, $connector, $host, $parts) {
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$resolved = $ip;
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$uri = '';
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// prepend original scheme if known
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if (isset($parts['scheme'])) {
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$uri .= $parts['scheme'] . '://';
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}
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if (\strpos($ip, ':') !== false) {
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// enclose IPv6 addresses in square brackets before appending port
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$uri .= '[' . $ip . ']';
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} else {
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$uri .= $ip;
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}
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// append original port if known
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if (isset($parts['port'])) {
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$uri .= ':' . $parts['port'];
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}
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// append orignal path if known
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if (isset($parts['path'])) {
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$uri .= $parts['path'];
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}
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// append original query if known
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if (isset($parts['query'])) {
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$uri .= '?' . $parts['query'];
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}
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// append original hostname as query if resolved via DNS and if
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// destination URI does not contain "hostname" query param already
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$args = array();
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\parse_str(isset($parts['query']) ? $parts['query'] : '', $args);
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if ($host !== $ip && !isset($args['hostname'])) {
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$uri .= (isset($parts['query']) ? '&' : '?') . 'hostname=' . \rawurlencode($host);
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}
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// append original fragment if known
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if (isset($parts['fragment'])) {
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$uri .= '#' . $parts['fragment'];
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}
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$promise = $connector->connect($uri);
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$promise->then($resolve, $reject);
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},
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function ($_, $reject) use (&$promise, &$resolved, $uri) {
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// cancellation should reject connection attempt
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// (try to) cancel pending connection attempt
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if ($resolved === null) {
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$reject(new \RuntimeException('Connection to ' . $uri . ' cancelled during connection attempt'));
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}
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if ($promise instanceof CancellablePromiseInterface) {
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// overwrite callback arguments for PHP7+ only, so they do not show
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// up in the Exception trace and do not cause a possible cyclic reference.
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$_ = $reject = null;
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$promise->cancel();
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$promise = null;
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}
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}
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);
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}
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}

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