Add flood control

closes #271

js/lib/App.js

@@ -263,6 +263,10 @@ export default class App {
           children = app.translator.trans('core.lib.error.not_found_message');
           break;
 
+        case 429:
+          children = app.translator.trans('core.lib.error.rate_limit_exceeded_message');
+          break;
+
         default:
           children = app.translator.trans('core.lib.error.generic_message');
       }

src/Core/Command/StartDiscussionHandler.php

@@ -60,7 +60,7 @@ public function handle(StartDiscussion $command)
         $this->assertCan($actor, 'startDiscussion');
 
         // Create a new Discussion entity, persist it, and dispatch domain
-        // events. Before persistance, though, fire an event to give plugins
+        // events. Before persistence, though, fire an event to give plugins
         // an opportunity to alter the discussion entity based on data in the
         // command they may have passed through in the controller.
         $discussion = Discussion::start(

src/Core/CoreServiceProvider.php

@@ -91,6 +91,7 @@ public function boot()
         $events->subscribe('Flarum\Core\Listener\UserMetadataUpdater');
         $events->subscribe('Flarum\Core\Listener\EmailConfirmationMailer');
         $events->subscribe('Flarum\Core\Listener\DiscussionRenamedNotifier');
+        $events->subscribe('Flarum\Core\Listener\FloodController');
 
         $events->subscribe('Flarum\Core\Access\DiscussionPolicy');
         $events->subscribe('Flarum\Core\Access\GroupPolicy');

src/Core/Exception/FloodingException.php

@@ -0,0 +1,33 @@
+<?php
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Core\Exception;
+
+use Exception;
+use Tobscure\JsonApi\Exception\JsonApiSerializableInterface;
+
+class FloodingException extends Exception implements JsonApiSerializableInterface
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function getStatusCode()
+    {
+        return 429;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getErrors()
+    {
+        return [];
+    }
+}

src/Core/Listener/FloodController.php

@@ -0,0 +1,75 @@
+<?php
+/*
+ * This file is part of Flarum.
+ *
+ * (c) Toby Zerner <toby.zerner@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Flarum\Core\Listener;
+
+use DateTime;
+use Flarum\Core\Exception\FloodingException;
+use Flarum\Core\Post;
+use Flarum\Core\User;
+use Flarum\Event\DiscussionWillBeSaved;
+use Flarum\Event\PostWillBeSaved;
+use Illuminate\Contracts\Events\Dispatcher;
+
+class FloodController
+{
+    /**
+     * @param Dispatcher $events
+     */
+    public function subscribe(Dispatcher $events)
+    {
+        $events->listen(DiscussionWillBeSaved::class, [$this, 'whenDiscussionWillBeSaved']);
+        $events->listen(PostWillBeSaved::class, [$this, 'whenPostWillBeSaved']);
+    }
+
+    /**
+     * @param DiscussionWillBeSaved $event
+     */
+    public function whenDiscussionWillBeSaved(DiscussionWillBeSaved $event)
+    {
+        if ($event->discussion->exists) {
+            return;
+        }
+
+        $this->assertNotFlooding($event->actor);
+    }
+
+    /**
+     * @param PostWillBeSaved $event
+     */
+    public function whenPostWillBeSaved(PostWillBeSaved $event)
+    {
+        if ($event->post->exists) {
+            return;
+        }
+
+        $this->assertNotFlooding($event->actor);
+    }
+
+    /**
+     * @param User $actor
+     * @throws FloodingException
+     */
+    protected function assertNotFlooding(User $actor)
+    {
+        if ($this->isFlooding($actor)) {
+            throw new FloodingException;
+        }
+    }
+
+    /**
+     * @param User $actor
+     * @return bool
+     */
+    protected function isFlooding(User $actor)
+    {
+        return Post::where('user_id', $actor->id)->where('time', '>=', new DateTime('-10 seconds'))->exists();
+    }
+}