Make happy eyeballs available in Connector with a flag

We'll set it to off until version 2.0.0 to ensure backwards
compatibility.

Author: WyriHaximus

README.md

@@ -1061,7 +1061,7 @@ pass an instance implementing the `ConnectorInterface` like this:
 ```php
 $dnsResolverFactory = new React\Dns\Resolver\Factory();
 $resolver = $dnsResolverFactory->createCached('127.0.1.1', $loop);
-$tcp = new React\Socket\DnsConnector(new React\Socket\TcpConnector($loop), $resolver);
+$tcp = new React\Socket\HappyEyeBallsConnector($loop, new React\Socket\TcpConnector($loop), $resolver);
 
 $tls = new React\Socket\SecureConnector($tcp, $loop);
 
@@ -1094,6 +1094,17 @@ $connector->connect('google.com:80')->then(function (React\Socket\ConnectionInte
   Internally, the `tcp://` and `tls://` connectors will always be wrapped by
   `TimeoutConnector`, unless you disable timeouts like in the above example.
 
+> Internally the `HappyEyeBallsConnector` has replaced the `DnsConnector` as default 
+  resolving connector. It is still available as `Connector` has a new option, namely 
+  `happy_eyeballs`, to control which of the two will be used. By default it's `true` 
+  and will use `HappyEyeBallsConnector`, when set to `false` `DnsConnector` is used. 
+  We only recommend doing so when there are any backwards compatible issues on older 
+  systems only supporting IPv4. The `HappyEyeBallsConnector` implements most of 
+  RFC6555 and RFC8305 and will use concurrency to connect to the remote host by
+  attempting to connect over both IPv4 and IPv6 with a priority for IPv6 when 
+  available. Which ever connection attempt succeeds first will be used, the rest 
+  connection attempts will be canceled.
+
 ### Advanced client usage
 
 #### TcpConnector

composer.json

@@ -14,7 +14,8 @@
     },
     "require-dev": {
         "clue/block-react": "^1.2",
-        "phpunit/phpunit": "^6.4 || ^5.7 || ^4.8.35"
+        "phpunit/phpunit": "^6.4 || ^5.7 || ^4.8.35",
+        "react/promise-stream": "^1.2"
     },
     "autoload": {
         "psr-4": {

src/Connector.php

@@ -36,6 +36,7 @@ public function __construct(LoopInterface $loop, array $options = array())
 
             'dns' => true,
             'timeout' => true,
+            'happy_eyeballs' => \PHP_VERSION_ID < 70000 ? false : true,
         );
 
         if ($options['timeout'] === true) {
@@ -70,7 +71,11 @@ public function __construct(LoopInterface $loop, array $options = array())
                 );
             }
 
-            $tcp = new DnsConnector($tcp, $resolver);
+            if ($options['happy_eyeballs'] === true) {
+                $tcp = new HappyEyeBallsConnector($loop, $tcp, $resolver);
+            } else {
+                $tcp = new DnsConnector($tcp, $resolver);
+            }
         }
 
         if ($options['tcp'] !== false) {

tests/ConnectorTest.php

@@ -100,7 +100,8 @@ public function testConnectorUsesGivenResolverInstance()
         $resolver->expects($this->once())->method('resolve')->with('google.com')->willReturn($promise);
 
         $connector = new Connector($loop, array(
-            'dns' => $resolver
+            'dns' => $resolver,
+            'happy_eyeballs' => false,
         ));
 
         $connector->connect('google.com:80');
@@ -120,7 +121,8 @@ public function testConnectorUsesResolvedHostnameIfDnsIsUsed()
 
         $connector = new Connector($loop, array(
             'tcp' => $tcp,
-            'dns' => $resolver
+            'dns' => $resolver,
+            'happy_eyeballs' => false,
         ));
 
         $connector->connect('tcp://google.com:80');

tests/FunctionalConnectorTest.php

@@ -4,12 +4,17 @@
 
 use Clue\React\Block;
 use React\EventLoop\Factory;
+use React\Socket\ConnectionInterface;
 use React\Socket\Connector;
+use React\Socket\ConnectorInterface;
 use React\Socket\TcpServer;
 
 class FunctionalConnectorTest extends TestCase
 {
-    const TIMEOUT = 1.0;
+    const TIMEOUT = 30.0;
+
+    private $ipv4;
+    private $ipv6;
 
     /** @test */
     public function connectionToTcpServerShouldSucceedWithLocalhost()
@@ -29,4 +34,172 @@ public function connectionToTcpServerShouldSucceedWithLocalhost()
         $connection->close();
         $server->close();
     }
+
+    /**
+     * @test
+     * @group internet
+     */
+    public function connectionToRemoteTCP4n6ServerShouldResultInOurIP()
+    {
+        $loop = Factory::create();
+
+        $connector = new Connector($loop, array('happy_eyeballs' => true));
+
+        $ip = Block\await($this->request('dual.tlund.se', $connector), $loop, self::TIMEOUT);
+
+        $this->assertSame($ip, filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4 | FILTER_FLAG_IPV6), $ip);
+    }
+
+    /**
+     * @test
+     * @group internet
+     */
+    public function connectionToRemoteTCP4ServerShouldResultInOurIP()
+    {
+        if ($this->ipv4() === false) {
+            // IPv4 not supported on this system
+            return;
+        }
+
+        $loop = Factory::create();
+
+        $connector = new Connector($loop, array('happy_eyeballs' => true));
+
+        $ip = Block\await($this->request('ipv4.tlund.se', $connector), $loop, self::TIMEOUT);
+
+        $this->assertSame($ip, filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4), $ip);
+        $this->assertFalse(filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6), $ip);
+    }
+
+    /**
+     * @test
+     * @group internet
+     */
+    public function connectionToRemoteTCP6ServerShouldResultInOurIP()
+    {
+        if ($this->ipv6() === false) {
+            // IPv6 not supported on this system
+            return;
+        }
+
+        $loop = Factory::create();
+
+        $connector = new Connector($loop, array('happy_eyeballs' => true));
+
+        $ip = Block\await($this->request('ipv6.tlund.se', $connector), $loop, self::TIMEOUT);
+
+        $this->assertFalse(filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4), $ip);
+        $this->assertSame($ip, filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6), $ip);
+    }
+
+    /**
+     * @test
+     * @group internet
+     *
+     * @expectedException \RuntimeException
+     * @expectedExceptionMessageRegExp /Connection to ipv6.tlund.se:80 failed/
+     */
+    public function tryingToConnectToAnIPv6OnlyHostWithOutHappyEyeBallsShouldResultInFailure()
+    {
+        $loop = Factory::create();
+
+        $connector = new Connector($loop, array('happy_eyeballs' => false));
+
+        Block\await($this->request('ipv6.tlund.se', $connector), $loop, self::TIMEOUT);
+    }
+
+    /**
+     * @test
+     * @group internet
+     *
+     * @expectedException \RuntimeException
+     * @expectedExceptionMessageRegExp /Connection to tcp:\/\/193.15.228.195:80 failed:/
+     */
+    public function connectingDirectlyToAnIPv4AddressShouldFailWhenIPv4IsntAvailable()
+    {
+        if ($this->ipv4() === true) {
+            // IPv4 supported on this system
+            throw new \RuntimeException('Connection to tcp://193.15.228.195:80 failed:');
+        }
+
+        $loop = Factory::create();
+
+        $connector = new Connector($loop);
+
+        $host = current(dns_get_record('ipv4.tlund.se', DNS_A));
+        $host = $host['ip'];
+        Block\await($this->request($host, $connector), $loop, self::TIMEOUT);
+    }
+
+    /**
+     * @test
+     * @group internet
+     *
+     * @expectedException \RuntimeException
+     * @expectedExceptionMessageRegExp /Connection to tcp:\/\/\[2a00:801:f::195\]:80 failed:/
+     */
+    public function connectingDirectlyToAnIPv6AddressShouldFailWhenIPv6IsntAvailable()
+    {
+        if ($this->ipv6() === true) {
+            // IPv6 supported on this system
+            throw new \RuntimeException('Connection to tcp://[2a00:801:f::195]:80 failed:');
+        }
+
+        $loop = Factory::create();
+
+        $connector = new Connector($loop);
+
+        $host = current(dns_get_record('ipv6.tlund.se', DNS_AAAA));
+        $host = $host['ipv6'];
+        $host = '[' . $host . ']';
+        $ip = Block\await($this->request($host, $connector), $loop, self::TIMEOUT);
+
+        $this->assertFalse(filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4), $ip);
+        $this->assertSame($ip, filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV6), $ip);
+    }
+
+    /**
+     * @internal
+     */
+    public function parseIpFromPage($body)
+    {
+        $ex = explode('title="Look up on bgp.he.net">', $body);
+        $ex = explode('<', $ex[1]);
+
+        return $ex[0];
+    }
+
+    private function request($host, ConnectorInterface $connector)
+    {
+        $that = $this;
+        return $connector->connect($host . ':80')->then(function (ConnectionInterface $connection) use ($host) {
+            $connection->write("GET / HTTP/1.1\r\nHost: " . $host . "\r\n\r\n");
+
+            return \React\Promise\Stream\buffer($connection);
+        })->then(function ($response) use ($that) {
+            return $that->parseIpFromPage($response);
+        });
+    }
+
+    private function ipv4()
+    {
+        if ($this->ipv4 !== null) {
+            return $this->ipv4;
+        }
+
+        $this->ipv4 = !!@file_get_contents('http://ipv4.tlund.se/');
+
+        return $this->ipv4;
+    }
+
+    private function ipv6()
+    {
+        if ($this->ipv6 !== null) {
+            return $this->ipv6;
+        }
+
+        $this->ipv6 = !!@file_get_contents('http://ipv6.tlund.se/');
+
+        return $this->ipv6;
+    }
 }