BookStack\Services\PermissionService::getBook PHP Method

    protected function getBook($bookId)
    {
        if (isset($this->entityCache['books']) && $this->entityCache['books']->has($bookId)) {
            return $this->entityCache['books']->get($bookId);
        }
        $book = $this->book->find($bookId);
        if ($book === null) {
            $book = false;
        }
        if (isset($this->entityCache['books'])) {
            $this->entityCache['books']->put($bookId, $book);
        }
        return $book;
    }