e-bike-tracker-server-ws/src/main.rs

use futures_util::{
    StreamExt,
    stream::{
        SplitSink,
        SplitStream,
        Stream,
    },
};
use tokio::{
    time::{
        Duration,
        interval,
    },
    net::{
        TcpListener,
        TcpStream,
    },
};
use tokio_tungstenite::{
    accept_async_with_config,
    WebSocketStream,
    tungstenite::{
        Message,
        Result,
        Error as WsError,
        protocol::WebSocketConfig,
    },
};
use tokio_stream::wrappers::IntervalStream;

type WsTx = SplitSink<WebSocketStream<tokio::net::TcpStream>, Message>;
type WsRx = SplitStream<WebSocketStream<tokio::net::TcpStream>>;

async fn accept(tcp_stream: TcpStream) -> Result<WebSocketStream<TcpStream>, WsError> {
    let wsconfig = WebSocketConfig {
        max_send_queue: Some(5),
        max_message_size: None,
        max_frame_size: None,
        accept_unmasked_frames: false,
    };
    accept_async_with_config(tcp_stream, Some(wsconfig)).await
}

async fn handle(mut rx: WsRx) -> anyhow::Result<()> {
    println!("enter incoming loop");
    while let Some(msg) = rx.next().await {
        match msg {
            Ok(Message::Text(x)) => { println!("Got Text Message: {x:?}"); },
            Ok(x) => { println!("Got another Message: {x:?}"); },
            Err(x) => { println!("Got ERROR: {x:?}"); },
        }
    }
    Ok(())
}

async fn serve<S: Stream<Item = String>>(tx: WsTx, input: S) -> Result<(), WsError> {
    input
        .map(Message::Text)
        .map(Ok)
        .forward(tx).await
}

#[tokio::main]
async fn main() -> anyhow::Result<()> {
    let listener = TcpListener::bind("127.0.0.1:8080").await?;

    while let Ok((tcp_stream, addr)) = listener.accept().await {
        println!("Got a connection from: {addr}");

        let ws_result = accept(tcp_stream).await;
        let (tx, rx) = ws_result.map(|ws| ws.split())?;

        // in reality this is an mqtt stream
        let interval_stream = IntervalStream::new(interval(Duration::from_secs(1)));
        let stream = interval_stream.zip(futures_util::stream::repeat("djshjh".to_string()))
            .map(|(i, txt)| format!("{i:?}: {txt}"));

        tokio::select! {
            res = handle(rx) => println!("Done waiting for messages. Reason: {res:?}"),
            _ = serve(tx, stream) => println!("Done serving locations.")
        }
    }

    Ok(())
}