Update DNS dependency and load system default DNS config on all supported platforms

README.md

@@ -11,7 +11,6 @@ Once [installed](#install), you can use the following code to connect to an UDP
 
 ```php
 $loop = React\EventLoop\Factory::create();
-
 $factory = new React\Datagram\Factory($loop);
 
 $factory->createClient('localhost:1234')->then(function (React\Datagram\Socket $client) {

composer.json

@@ -17,7 +17,7 @@
         "php": ">=5.3",
         "evenement/evenement": "^3.0 || ^2.0 || ^1.0",
         "react/event-loop": "^1.0 || ^0.5 || ^0.4 || ^0.3",
-        "react/dns": "^0.4.11",
+        "react/dns": "^0.4.13",
         "react/promise": "~2.1|~1.2"
     },
     "require-dev": {

examples/client.php

@@ -3,11 +3,7 @@
 require_once __DIR__.'/../vendor/autoload.php';
 
 $loop = React\EventLoop\Factory::create();
-
-$factory = new React\Dns\Resolver\Factory();
-$resolver = $factory->createCached('8.8.8.8', $loop);
-
-$factory = new React\Datagram\Factory($loop, $resolver);
+$factory = new React\Datagram\Factory($loop);
 
 $factory->createClient('localhost:1234')->then(function (React\Datagram\Socket $client) use ($loop) {
     $client->send('first');

examples/server.php

@@ -3,7 +3,6 @@
 require_once __DIR__.'/../vendor/autoload.php';
 
 $loop = React\EventLoop\Factory::create();
-
 $factory = new React\Datagram\Factory($loop);
 
 $factory->createServer('localhost:1234')->then(function (React\Datagram\Socket $server) {

src/Factory.php

@@ -3,6 +3,7 @@
 namespace React\Datagram;
 
 use React\Datagram\Socket;
+use React\Dns\Config\Config;
 use React\Dns\Resolver\Factory as DnsFactory;
 use React\Dns\Resolver\Resolver;
 use React\EventLoop\LoopInterface;
@@ -19,13 +20,18 @@ class Factory
      *
      * @param LoopInterface $loop
      * @param Resolver|null $resolver Resolver instance to use. Will otherwise
-     *     default to using Google's public DNS 8.8.8.8
+     *     try to load the system default DNS config or fall back to using
+     *     Google's public DNS 8.8.8.8
      */
     public function __construct(LoopInterface $loop, Resolver $resolver = null)
     {
         if ($resolver === null) {
+            // try to load nameservers from system config or default to Google's public DNS
+            $config = Config::loadSystemConfigBlocking();
+            $server = $config->nameservers ? reset($config->nameservers) : '8.8.8.8';
+
             $factory = new DnsFactory();
-            $resolver = $factory->create('8.8.8.8', $loop);
+            $resolver = $factory->create($server, $loop);
         }
 
         $this->loop = $loop;