SecureConnector: add optional TlsPeer, this...

...allows to capture your peer certificate and/or it's chain

README.md

@@ -1322,6 +1322,33 @@ $secureConnector = new React\Socket\SecureConnector($dnsConnector, $loop, array(
 ));
 ```
 
+In case you want to retrieve your peers certificate or certificate chain,
+you can use the related context options:
+
+```php
+$secureConnector = new React\Socket\SecureConnector($dnsConnector, $loop, array(
+    'capture_peer_cert' => true,
+    'capture_peer_cert_chain' => true,
+));
+```
+
+To show the peer certificate for every new connection this can be done as
+follows:
+
+```php
+$secureConnector->connect('www.google.com:80')->then(function (React\Socket\ConnectionInterface $connection) {
+    assert($connection instanceof React\Socket\Connection);
+    if ($connection->hasTlsPeer()) {
+        $peer = $connection->getTlsPeer();
+        if ($peer && $peer->hasPeerCertificate()) {
+            $peerCert = $peer->getPeerCertificate();
+            openssl_x509_export($peerCert, $cert);
+            echo $cert;
+        }
+    }
+});
+```
+
 By default, this connector supports TLSv1.0+ and excludes support for legacy
 SSLv2/SSLv3. As of PHP 5.6+ you can also explicitly choose the TLS version you
 want to negotiate with the remote side:

src/Connection.php

@@ -41,6 +41,9 @@ class Connection extends EventEmitter implements ConnectionInterface
 
     private $input;
 
+    /** @var TlsPeer|null */
+    private $tlsPeer;
+
     public function __construct($resource, LoopInterface $loop)
     {
         // PHP < 7.3.3 (and PHP < 7.2.15) suffers from a bug where feof() might
@@ -154,6 +157,31 @@ public function getLocalAddress()
         return $this->parseAddress(\stream_socket_get_name($this->stream, false));
     }
 
+    /**
+     * @param TlsPeer $peer
+     * @internal
+     */
+    public function setTlsPeer(TlsPeer $peer = null)
+    {
+        $this->tlsPeer = $peer;
+    }
+
+    /**
+     * @return bool
+     */
+    public function hasTlsPeer()
+    {
+        return $this->tlsPeer !== null;
+    }
+
+    /**
+     * @return TlsPeer|null
+     */
+    public function getTlsPeer()
+    {
+        return $this->tlsPeer;
+    }
+
     private function parseAddress($address)
     {
         if ($address === false) {

src/SecureConnector.php

@@ -56,7 +56,11 @@ public function connect($uri)
             }
 
             // try to enable encryption
-            return $promise = $encryption->enable($connection)->then(null, function ($error) use ($connection, $uri) {
+            return $promise = $encryption->enable($connection)->then(function () use ($connection) {
+                $connection->setTlsPeer(new TlsPeer(\stream_context_get_params($connection->stream)));
+
+                return $connection;
+            }, function ($error) use ($connection, $uri) {
                 // establishing encryption failed => close invalid connection and return error
                 $connection->close();
 

src/TlsPeer.php

@@ -0,0 +1,70 @@
+<?php
+
+namespace React\Socket;
+
+class TlsPeer
+{
+    private $peerCertificate;
+    private $peerCertificateChain;
+
+    public function __construct($context)
+    {
+        if (isset($context['options']['ssl']['peer_certificate'])) {
+            $this->peerCertificate = $context['options']['ssl']['peer_certificate'];
+        }
+        if (isset($context['options']['ssl']['peer_certificate_chain'])) {
+            $this->peerCertificateChain = $context['options']['ssl']['peer_certificate_chain'];
+        }
+    }
+
+    /**
+     * @return bool
+     */
+    public function hasPeerCertificate()
+    {
+        return $this->peerCertificate !== null;
+    }
+
+    /**
+     * @return null|resource (OpenSSL x509)
+     */
+    public function getPeerCertificate()
+    {
+        return $this->peerCertificate;
+    }
+
+    /**
+     * @return bool
+     */
+    public function hasPeerCertificateChain()
+    {
+        return $this->peerCertificateChain !== null;
+    }
+
+    /**
+     * @return null|array of OpenSSL x509 resources
+     */
+    public function getPeerCertificateChain()
+    {
+        return $this->peerCertificateChain;
+    }
+
+    protected function free()
+    {
+        if ($this->peerCertificate) {
+            \openssl_x509_free($this->peerCertificate);
+            $this->peerCertificate = null;
+        }
+        if (\is_array($this->peerCertificateChain)) {
+            foreach ($this->peerCertificateChain as $cert) {
+                \openssl_x509_free($cert);
+            }
+            $this->peerCertificateChain = null;
+        }
+    }
+
+    public function __destruct()
+    {
+        $this->free();
+    }
+}