Function broadcast_ws

websockets/echo-actorless/src/handler.rs:162–264

Broadcast text & binary messages received from a client, respond to ping messages, and monitor connection health to detect network issues and free up resources.

(
    mut session: actix_ws::Session,
    mut msg_stream: actix_ws::MessageStream,
    mut rx: broadcast::Receiver<web::Bytes>,
)

/// Broadcast text & binary messages received from a client, respond to ping messages, and monitor
/// connection health to detect network issues and free up resources.
pub async fn broadcast_ws(
    mut session: actix_ws::Session,
    mut msg_stream: actix_ws::MessageStream,
    mut rx: broadcast::Receiver<web::Bytes>,
) {
    log::info!("connected");

    let mut last_heartbeat = Instant::now();
    let mut interval = interval(HEARTBEAT_INTERVAL);

    let reason = loop {
        // waits for either `msg_stream` to receive a message from the client, the broadcast channel
        // to send a message, or the heartbeat interval timer to tick, yielding the value of
        // whichever one is ready first
        select! {
            broadcast_msg = rx.recv() => {
                let msg = match broadcast_msg {
                    Ok(msg) => msg,
                    Err(broadcast::error::RecvError::Closed) => break None,
                    Err(broadcast::error::RecvError::Lagged(_)) => continue,
                };

                let res = match std::str::from_utf8(&msg) {
                    Ok(val) => session.text(val).await,
                    Err(_) => session.binary(msg).await,
                };

                if let Err(err) = res {
                    log::error!("{err}");
                    break None;
                }
            }

            // heartbeat interval ticked
            _tick = interval.tick() => {
                // if no heartbeat ping/pong received recently, close the connection
                if Instant::now().duration_since(last_heartbeat) > CLIENT_TIMEOUT {
                    log::info!(
                        "client has not sent heartbeat in over {CLIENT_TIMEOUT:?}; disconnecting"
                    );

                    break None;
                }

                // send heartbeat ping
                let _ = session.ping(b"").await;
            },

            msg = msg_stream.next() => {
                let msg = match msg {
                    // received message from WebSocket client
                    Some(Ok(msg)) => msg,

                    // client WebSocket stream error
                    Some(Err(err)) => {
                        log::error!("{err}");
                        break None;
                    }