+ * Check the current user's permissions against an ownable item otherwise throw an exception.
+ */
+ protected function checkOwnablePermission(string $permission, Model $ownable): void
+ {
+ if (!userCan($permission, $ownable)) {
+ $this->showPermissionError();
+ }
+ }
+
+ /**
+ * Check if a user has a permission or bypass the permission
+ * check if the given callback resolves true.
+ */
+ protected function checkPermissionOr(string $permission, callable $callback): void
+ {
+ if ($callback() !== true) {
+ $this->checkPermission($permission);
+ }
+ }
+
+ /**
+ * Check if the current user has a permission or bypass if the provided user
+ * id matches the current user.
+ */
+ protected function checkPermissionOrCurrentUser(string $permission, int $userId): void
+ {
+ $this->checkPermissionOr($permission, function () use ($userId) {
+ return $userId === user()->id;
+ });
+ }
+
+ /**
+ * Send back a json error message.
+ */
+ protected function jsonError(string $messageText = '', int $statusCode = 500): JsonResponse
+ {
+ return response()->json(['message' => $messageText, 'status' => 'error'], $statusCode);
+ }
+
+ /**
+ * Create and return a new download response factory using the current request.