Injecting a .clone() of the SocketIo struct into the on_connect().

[JustLeif]

Hey everyone! I am currently building a game server, and I'm trying to architect a system that can perform the following logic:

• When a player joins a room by ID, a background process is spawned (using tokio::spawn) that handles the game server logic (AI, player state, handling future player socket events)
• Emitting game state changes at an interval to all players in the room

In order to perform this logic, I think I need to inject a clone of the SocketIo struct into the room logic handler like so:

pub async fn raid_room_server(io: SocketIo, room_id: String) {
    loop {
        let _ = io
            .to(room_id.clone())
            .emit("raid-even", "Hello from the raid room you joined!"); // Handle updating state based on user inputs and AI movements, and the emit the changes to the client every 100 ms
        sleep(Duration::from_millis(100)).await;
    }
}

Now inside this tokio task, I can concurrently handle a room session while emitting events (though I have not figured out how to get future socket events of players connected to the room.

So here if the problematic lines of code:

socket.on(
        "join_raid",
        |socket: SocketRef, Data::<JoinRaidSocketEvent>(data), Bin(bin)| async move {
            info!("Received event: {:?} {:?}", data, bin);
            info!("Log the Socket: {:?}", socket);
            let _ = socket.leave_all();
            let _ = socket.join([data.raid_id]);
            let handler = tokio::spawn(raid_room_server(io, data.raid_id)); // right now 'io' does not exist because I don't know how to inject it into this closure
            info!("{:?}", socket.rooms());
        },
    );

I'm very curious if anyone has come across this type of problem and have a better solution than the one I suggested, or if it is a decent solution what is the remedy? Thank you!

[Totodore]

Hello ! Indeed you cannot inject the io struct in a handler with extractors. But what you can do is using the move keyword on your closure declaration to move the io ref from the parent scope. See: https://doc.rust-lang.org/std/keyword.move.html

In your case:

let io1 = io.clone();
socket.on(
        "join_raid",
        move |socket: SocketRef, Data::<JoinRaidSocketEvent>(data), Bin(bin)| async move {
            info!("Received event: {:?} {:?}", data, bin);
            info!("Log the Socket: {:?}", socket);
            let _ = socket.leave_all();
            let _ = socket.join([data.raid_id]);
            let handler = tokio::spawn(raid_room_server(io1, data.raid_id));
            info!("{:?}", socket.rooms());
        },
    );

We clone the io ref to a new io1 so that io1 is moved into the closure and that you can still later use the io into the main scope. There is no need to do that if you don't need it in the main scope.

[JustLeif]

Ahh love it when my issue is forgetting basic rust syntax haha.

Thank you very much for your help!