pub async fn list_backups(pool: &State<sqlx::Pool<MySql>>, page: Option<i64>, per_page: Option<i64>) -> Json<Vec<Backup>> {
    let page = page.unwrap_or(1);

pub async fn list_backups_by_app_id(pool: &State<sqlx::Pool<MySql>>, app_id: &str, page: Option<i64>, page_size: Option<i64>) -> Json<Vec<Backup>> {
    let app_id = app_id.parse::<i64>().unwrap_or(0);

pub async fn get_backup(pool: &State<sqlx::Pool<MySql>>, backup_id: &str) -> Json<Option<Backup>> {
    let backup_id = backup_id.parse::<i64>().unwrap_or(0);

pub async fn create_backup(
    pool: &State<sqlx::Pool<MySql>>,
    new_backup: Json<Backup>,
) -> Result<Json<Backup>, rocket::http::Status> {
    // ... function body
}