Data Duplication

[mmacfadden]

Thanks for your work on this project. It's very helpful! I have run into an odd issue where nectar seems to be duplicating some data. I have provided some code that duplicates the issue.

Here is some of the output. First is some screen captures from Wireshark:

TELNET FRAME 1

Wireshark

Console Output

TELNET FRAME 2

Wireshark

Console Output

In the data it looks like some of the lines are not terminated with \r\n. The next frame seems to have escape code and then the \r\n. But the line in the prior frame seems to be duplicated in the TelnetEvent::Message event.

So for example:

      _________|______|_____  @   @@@@@ @   @   @  _____|______|_________

Is turned into:

     _________|______|_____  @   @@@@@ @   @   @  _____|______|_________      _________|______|_____  @   @@@@@ @   @   @  _____|______|_________\u{1b}[H

Here is a way to duplicate the issue:

use std::error::Error;
use futures_lite::StreamExt;
use futures_util::SinkExt;
use nectar::{event::TelnetEvent, TelnetCodec};
use tokio::net::TcpStream;
use tokio_util::codec::Framed;

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    let address = "towel.blinkenlights.nl:23";
    let tcp_stream = TcpStream::connect(address).await.unwrap();
    let codec = TelnetCodec::new(2048);
    let mut telnet = Framed::new(tcp_stream, codec);

    let mut count = 0;

    loop {
        if let Some(msg) = telnet.next().await {
            match msg {
                Ok(evt) => {
                    match evt {
                        TelnetEvent::Message(message) => {
                            count = count + 1;
                            println!("{:0>4}{:?}", count, message);

                            if count > 205 {
                                break;
                            }
                        }
                        _ => {
                            println!("unhandled telnet event: {:?}", evt);
                        }
                    }
                }
                Err(err) => {
                    println!("telnet error: {:?}", err);
                }
            }
        } else {
            break;
        }
    }

    telnet.close().await.unwrap();

    Ok(())
}

[mmacfadden]

Here is a zip file of the wireshark packet capture if that is helpful.

telnet.pcapng.zip