is in substate use clone get owner ship is a good choice

[joebnb]

use axum::{Router, routing::get, extract::{State, FromRef}};

// the application state
#[derive(Clone)]
struct AppState {
    // that holds some api specific state
    api_state: ApiState,
}

// the api specific state
#[derive(Clone)]
struct ApiState {}

// support converting an `AppState` in an `ApiState`
impl FromRef<AppState> for ApiState {
    fn from_ref(app_state: &AppState) -> ApiState {
        app_state.api_state.clone()
    }
}

let state = AppState {
    api_state: ApiState {},
};

let app = Router::new()
    .route("/", get(handler))
    .route("/api/users", get(api_users))
    .with_state(state);

async fn api_users(
    // access the api specific state
    State(api_state): State<ApiState>,
) {
}

async fn handler(
    // we can still access to top level state
    State(state): State<AppState>,
) {
}

im new bee of rust and axum,im my view clone is expensive,is there a good way to get substate owner ship

[davidpdrsn]

It depends on what data is in your state. It it has a database connection pool then it’s fine. If it holds 2gb of binary data then it’s probably not fine.

[joebnb]

i want add memory session store in here it's seems a little bit tough,would you please share some parttens or some mind of good design?

this is my session store and i want use it in handler and middleware

[davidpdrsn]

I'd recommend you join the tokio discord and ask in #axum. There are more people there who can help :)