Factory.php

<?php

namespace React\Dns\Resolver;

use React\Cache\ArrayCache;
use React\Cache\CacheInterface;
use React\Dns\Config\HostsFile;
use React\Dns\Query\CachingExecutor;
use React\Dns\Query\CoopExecutor;
use React\Dns\Query\ExecutorInterface;
use React\Dns\Query\HostsFileExecutor;
use React\Dns\Query\RetryExecutor;
use React\Dns\Query\TimeoutExecutor;
use React\Dns\Query\UdpTransportExecutor;
use React\EventLoop\LoopInterface;

class Factory
{
    public function create($nameserver, LoopInterface $loop)
    {
        $executor = $this->decorateHostsFileExecutor($this->createRetryExecutor($nameserver, $loop));

        return new Resolver($executor);
    }

    public function createCached($nameserver, LoopInterface $loop, CacheInterface $cache = null)
    {
        // default to keeping maximum of 256 responses in cache unless explicitly given
        if (!($cache instanceof CacheInterface)) {
            $cache = new ArrayCache(256);
        }

        $executor = $this->decorateHostsFileExecutor($this->createCachedExecutor($nameserver, $loop, $cache));

        return new Resolver($executor);
    }

    /**
     * Tries to load the hosts file and decorates the given executor on success
     *
     * @param ExecutorInterface $executor
     * @return ExecutorInterface
     * @codeCoverageIgnore
     */
    private function decorateHostsFileExecutor(ExecutorInterface $executor)
    {
        try {
            $executor = new HostsFileExecutor(
                HostsFile::loadFromPathBlocking(),
                $executor
            );
        } catch (\RuntimeException $e) {
            // ignore this file if it can not be loaded
        }

        // Windows does not store localhost in hosts file by default but handles this internally
        // To compensate for this, we explicitly use hard-coded defaults for localhost
        if (DIRECTORY_SEPARATOR === '\\') {
            $executor = new HostsFileExecutor(
                new HostsFile("127.0.0.1 localhost\n::1 localhost"),
                $executor
            );
        }

        return $executor;
    }

    protected function createExecutor($nameserver, LoopInterface $loop)
    {
        return new TimeoutExecutor(
            new UdpTransportExecutor(
                $nameserver,
                $loop
            ),
            5.0,
            $loop
        );
    }

    protected function createRetryExecutor($namserver, LoopInterface $loop)
    {
        return new CoopExecutor(new RetryExecutor($this->createExecutor($namserver, $loop)));
    }

    protected function createCachedExecutor($namserver, LoopInterface $loop, CacheInterface $cache)
    {
        return new CachingExecutor($this->createRetryExecutor($namserver, $loop), $cache);
    }
}