How I shutdown WriteHalf outside

[windniw]

Hey, I'm new in rust and tokio~

tokio/examples/proxy.rs

Lines 60 to 79 in e42317b

	async fn transfer(mut inbound: TcpStream, proxy_addr: String) -> Result<(), Box<dyn Error>> {
	let mut outbound = TcpStream::connect(proxy_addr).await?;
	let (mut ri, mut wi) = inbound.split();
	let (mut ro, mut wo) = outbound.split();
	let client_to_server = async {
	io::copy(&mut ri, &mut wo).await?;
	wo.shutdown().await
	};
	let server_to_client = async {
	io::copy(&mut ro, &mut wi).await?;
	wi.shutdown().await
	};
	tokio::try_join!(client_to_server, server_to_client)?;
	Ok(())
	}

I would like to cancel both sides if any task return, but I do not how to move wo and wi. Could anyone help me?

    let (mut ri, mut wi) = inbound.split();
    let (mut ro, mut wo) = outbound.split();

    let client_to_server = async {
        io::copy(&mut ri, &mut wo).await?;
        wo.shutdown().await;
        wi.shutdown().await;
    };

    let server_to_client = async {
        io::copy(&mut ro, &mut wi).await?;
        wi.shutdown().await;
        wo.shutdown().await;
    };

    tokio::try_join!(client_to_server, server_to_client)?;

[Darksonn]

How about this?

let (mut ri, mut wi) = inbound.split();
let (mut ro, mut wo) = outbound.split();

// This runs both until _one_ of them returns.
tokio::select! {
    res = io::copy(&mut ri, &mut wo) => res?,
    res = io::copy(&mut ro, &mut wi) => res?,
}

wi.shutdown().await?;
wo.shutdown().await?;

[windniw]

It looks work~ thx

[ririsoft]

Hello,

I am wondering if this could lead to a connection leak on either client or backend side due to early return on io::copy errors ?
What about something like this :

let (mut ri, mut wi) = inbound.split();
let (mut ro, mut wo) = outbound.split();

// This runs both until _one_ of them returns.
let res = tokio::select! {
    res = io::copy(&mut ri, &mut wo) => res.map(|_| ()),
    res = io::copy(&mut ro, &mut wi) => res.map(|_| ()),
};

// returns the first of io::copy, wi.shutdown() or wo.shutdown() error.

let res = match wi.shutdown().await {
    _ if res.is_err() => res,
    res => res,
};

match wo.shutdown().await {
    _ if res.is_err() => res,
    res => res,
}

What do you think ? Is this worth it or the tcp connections are closed on TcpStream drop ?

[Darksonn]

or the tcp connections are closed on TcpStream drop ?

The destructor of a TcpStream will close the connection.

[ririsoft]

Excellent, thanks a lot for your time and incredible work on tokio @Darksonn .