socket.io / nodejs / readline - disconnect does not end readline

I have the following code

var instream = request({url: 'http://ift.tt/19bp8wl'})
var outstream = new stream;
outstream.readable = true;
outstream.writable = true;

var rl = readline.createInterface({
    input: instream,
    output: outstream,
    terminal: false
});


io.sockets.on('connection', function(socket) {

rl.on('line', function(line) {
var data = JSON.parse(line)

...

io.to(socket.id).emit('message', data);
});

socket.on('disconnect', function(disconnect) {
// rl.close();
});

});

The problem I face is that even when the clients are correctly disconnected the rl.on line function is still looping for every user who was once connected to the website.

When I do

rl.close();

on disconnect it does remove the open rl.on but then it closes for all users the data stream since readline is closed globally.

How can I achieve it that the open readline process is stopped for users once they are disconnected from the site?