in chat example, how to reuse sender as it is moved

[yatesco]

Hi there, in line 94

axum/examples/chat/src/main.rs

Line 94 in b1623ce

let mut send_task = tokio::spawn(async move {

the sender is moved:

    // This task will receive broadcast messages and send text message to our client.
    let mut send_task = tokio::spawn(async move {
        while let Ok(msg) = rx.recv().await {
            // In any websocket error, break loop.
            if sender.send(Message::Text(msg)).await.is_err() {
                break;
            }
        }
    });

Because the sender can't be cloned, is it more idiomatic:

• wrapping it an rc of some kind (feels weird)
  or
• perform the select! of the various "business logic" channels (include the broadcast channel)?

I realise this is more a general design question - I'm just interested in the idioms here :-)

[davidpdrsn]

Putting the WebSocket in an arc wouldn't help because sending requires &mut self which you cannot get through an arc.

Is your use case that you need to send things on the socket from multiple places in your code concurrently?

[yatesco]

Exactly that.

…

On 11 Dec 2021, at 04:47, David Pedersen ***@***.***> wrote:  Putting the WebSocket in an arc wouldn't help because sending requires &mut self which you cannot get through an arc. Is your use case that you need to send things on the socket from multiple places in your code concurrently? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub, or unsubscribe. Triage notifications on the go with GitHub Mobile for iOS or Android.

[davidpdrsn]

I think I would make an mpsc channel and spawn a task to forward messages from the mpsc receiver to the socket sender. The mpsc sender can be cloned.

[yatesco]

Ah, got you. More and more I'm thinking of storing logic and state in the web socket loop itself is the wrong thing, and simply providing a channel to the actual "session"/logic is more idiomatic.

[davidpdrsn]

Yep I agree. Channels are the best 😊