Add authorization strategy for WAMP topics

lib/Alchemy/Phrasea/Websocket/Topics/DirectivesManager.php

@@ -0,0 +1,61 @@
+<?php
+
+/*
+ * This file is part of Phraseanet
+ *
+ * (c) 2005-2014 Alchemy
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Alchemy\Phrasea\Websocket\Topics;
+
+use Alchemy\Phrasea\Websocket\Consumer\ConsumerInterface;
+use Ratchet\Wamp\Topic;
+
+class DirectivesManager
+{
+    private $directives;
+
+    public function __construct(array $directives)
+    {
+        array_walk($directives, function ($directive) {
+            if (!$directive instanceof Directive) {
+                throw new \InvalidArgumentException('Websocket configuration only accepts configuration directives.');
+            }
+        });
+        $this->directives = $directives;
+    }
+
+    /**
+     * Returns true if the consumer has access to the given topic
+     *
+     * @param ConsumerInterface $consumer
+     * @param Topic             $topic
+     *
+     * @return Boolean
+     */
+    public function hasAccess(ConsumerInterface $consumer, Topic $topic)
+    {
+        foreach ($this->getDirectives($topic) as $directive) {
+            if (!$directive->isStatisfiedBy($consumer)) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    /**
+     * @param Topic $topic
+     *
+     * @return Directive[]
+     */
+    private function getDirectives(Topic $topic)
+    {
+        return array_filter($this->directives, function (Directive $directive) use ($topic) {
+            return $directive->getTopic() === $topic->getId();
+        });
+    }
+}