How to pass command to the server using ssh2-promise module node js?

Question

I have the following code:

var sshPromise=require('ssh2-promise');
var x={
    host:'host',
    username:'username',
    password:'mypassword'
};
var ssh=new sshPromise(x);

ssh.connect().then(()=>{
    console.log('connected...');
});

//Get a shell session
ssh.shell().then((socket) => {
    socket.on('data', (data) => {
        console.log(data.toString());

    })
    //Can write to socket 
    //console.log('here<--'); 
    socket.write('my password');// <----sending password to enter the server
});

what is trying to do here is I'm creating a shell session after connecting to a server.After connecting it asks me password to access the server and i want to send my password but it does nothing.

I did a little debugging by adding console.log('here<--') and realised that it gets printed right at the start before the data arrives, meaning the socket.write('my password') gets executed before the data arrives.

I can't figure out how to solve this. Can anyone please help me.

EDIT:

const socket = await ssh.shell();

const data = await new Promise(resolve => socket.on('data', resolve));
socket.write('my password\n');
//to fetch next shell output
const data_1= await new Promise(resolve => socket.on('data', resolve));

is there any way to call use the data multiple times rather than creating a new promise everytime i need to get output from the shell?

Answer 1

Using async / await you can wait for the "data" event to fire using a Promise:

const socket = await ssh.shell();

const data = await new Promise(resolve => socket.on('data', resolve));

socket.write('my password');

That way, socket.write is only called after you have data.

---

If this needs to be used multiple times, you could define a function:

const waitForDataAsync = socket => new Promise(resolve => socket.on('data', resolve));

Then use like this:

const socket = await ssh.shell();

const data = await waitForDataAsync(socket);
socket.write('my password\n');
//to fetch next shell output
const data_1 = await waitForDataAsync(socket);