get($id); if (!$category) { throw new BadRequestException('course_query.invalid_top_category'); } return $category->id; } public function checkSubCategory($id) { $categoryCache = new CategoryCache(); $category = $categoryCache->get($id); if (!$category) { throw new BadRequestException('course_query.invalid_sub_category'); } return $category->id; } public function checkLevel($level) { $types = CourseModel::levelTypes(); if (!isset($types[$level])) { throw new BadRequestException('course_query.invalid_level'); } return $level; } public function checkModel($model) { $types = CourseModel::modelTypes(); if (!isset($types[$model])) { throw new BadRequestException('course_query.invalid_model'); } return $model; } public function checkSort($sort) { $types = CourseModel::sortTypes(); if (!isset($types[$sort])) { throw new BadRequestException('course_query.invalid_sort'); } return $sort; } }