public function createComment($request, $db)
 {
     $comment = array();
     $comment['event_id'] = $this->getItemId($request);
     if (empty($comment['event_id'])) {
         throw new Exception("POST expects a comment representation sent to a specific event URL", 400);
     }
     // no anonymous comments over the API
     if (!isset($request->user_id) || empty($request->user_id)) {
         throw new Exception('You must log in to comment');
     }
     $user_mapper = new UserMapper($db, $request);
     $users = $user_mapper->getUserById($request->user_id);
     $thisUser = $users['users'][0];
     $rating = $request->getParameter('rating', false);
     if (false === $rating) {
         throw new Exception('The field "rating" is required', 400);
     } elseif (false === is_numeric($rating) || $rating > 5) {
         throw new Exception('The field "rating" must be a number (1-5)', 400);
     }
     $commentText = $request->getParameter('comment');
     if (empty($commentText)) {
         throw new Exception('The field "comment" is required', 400);
     }
     // Get the API key reference to save against the comment
     $oauth_model = $request->getOauthModel($db);
     $consumer_name = $oauth_model->getConsumerName($request->getAccessToken());
     $comment['user_id'] = $request->user_id;
     $comment['comment'] = $commentText;
     $comment['rating'] = $rating;
     $comment['cname'] = $thisUser['full_name'];
     $comment['source'] = $consumer_name;
     // run it by akismet if we have it
     if (isset($this->config['akismet']['apiKey'], $this->config['akismet']['blog'])) {
         $spamCheckService = new SpamCheckService($this->config['akismet']['apiKey'], $this->config['akismet']['blog']);
         $isValid = $spamCheckService->isCommentAcceptable($comment, $request->getClientIP(), $request->getClientUserAgent());
         if (!$isValid) {
             throw new Exception("Comment failed spam check", 400);
         }
     }
     $event_mapper = new EventMapper($db, $request);
     $comment_mapper = new EventCommentMapper($db, $request);
     // should rating be allowed?
     if ($comment_mapper->hasUserRatedThisEvent($comment['user_id'], $comment['event_id'])) {
         $comment['rating'] = 0;
     }
     if ($event_mapper->isUserAHostOn($comment['user_id'], $comment['event_id'])) {
         // event hosts cannot rate their own event
         $comment['rating'] = 0;
     }
     try {
         $new_id = $comment_mapper->save($comment);
     } catch (Exception $e) {
         // just throw this again but with a 400 status code
         throw new Exception($e->getMessage(), 400);
     }
     // Update the cache count for the number of event comments on this event
     $event_mapper->cacheCommentCount($comment['event_id']);
     $uri = $request->base . '/' . $request->version . '/event_comments/' . $new_id;
     header("Location: " . $uri, null, 201);
     exit;
 }