ssh_ui's Introduction

ssh_ui

ssh_ui helps you painlessly turn a cursive-based terminal UI (TUI) into an application accessible over ssh. Designed to make the creation of BBS systems or ssh-based games simple, ssh_ui takes a minimally opinionated approach to opening a TUI up to remote connections, beyond requiring you to use cursive. The ssh server implementation is provided by russh.

The main function of the simplest ssh_ui-based application looks something like this:

#[tokio::main]
async fn main() {
    let key_pair = KeyPair::generate_rsa(3072, SignatureHash::SHA2_256).unwrap();
    let mut server = AppServer::new_with_port(2222);
    let app = DialogApp {};
    server.run(&[key_pair], Arc::new(app)).await.unwrap();
}

First this generates a new keypair (but you should load several from disk for user-facing installations). Then it initializes a new AppServer on port 2222 and a new instance of a DialogApp, then calls AppServer::run to listen on the specified port for incoming connections. Let's look next at what makes AppServer tick.

struct DialogApp {}

impl App for DialogApp {
    fn on_load(&mut self) -> Result<(), Box<dyn Error>> {
        Ok(())
    }

    fn new_session(&self) -> Box<dyn AppSession> {
        Box::new(DialogAppSession::new())
    }
}

All it's doing here is providing a new DialogAppSession whenever there's a new incoming ssh connection. DialogAppSession is implemented as follows:

struct DialogAppSession {}

impl DialogAppSession {
    pub fn new() -> Self {
        Self {}
    }
}

impl AppSession for DialogAppSession {
    fn on_start(
        &mut self,
        _siv: &mut Cursive,
        _session_handle: SessionHandle,
        _pub_key: PublicKey,
        _force_refresh_sender: Sender<()>,
    ) -> Result<Box<dyn cursive::View>, Box<dyn Error>> {
        println!("on_start");
        Ok(Box::new(
            Dialog::around(TextView::new("Hello over ssh!"))
                .title("ssh_ui")
                .button("Quit", |s| s.quit()),
        ))
    }
}

This is where the actual cursive TUI is created and returned to ssh_ui. You can return whatever TUI you want, and ssh_ui will take care of serving it to the client.