How do you pass shared state into manual handler functions?

[alshdavid]

Hi all, I like to use the manual approach when it comes to defining my http services and am trying to inject variables/shared state into my handler functions using the age-old property injection approach.

I am struggling to do this with Actix - is there an ergonomic way to achieve what I'm trying to do?

#[tokio::main]
async fn main() -> std::io::Result<()> {
    let shared_state = Arc::new(RwLock::new(42)); // Pass this into my handlers

    HttpServer::new(move || {
      let mut app = App::new();

      app = app.route("/", web::get().to(handler_root(shared_state.clone()))); // invalid type for 'handler_root'

      app
    })
        .bind(("127.0.0.1", 8080))?
        .run()
        .await
}

// I assume this is an invalid type 
pub type HandlerFunc = Box<dyn Fn() -> Pin<Box<dyn Future<Output = HttpResponse>>>>;

// Factory function that returns my handler
fn handler_root(shared_state: Arc<RwLock<usize>>) -> HandlerFunc {
    Box::new(move || Box::pin({
      let shared_state = shared_state.clone();
      async move { 
          HttpResponse::Ok().body(format!("Hey there! {}", shared_state.read().await)) 
      }
    }))
}

[robjtede]

State is not passed to handlers like that. You can read about how to set up shared mutable state in the guide: https://actix.rs/docs/application#shared-mutable-state

Also see the docs for App::app_data() and the links through to Data<T>'s docs.