Node.js: trouble with listener

Question

I'm developing my first app in Node.js and I think I don't understand correctly yet how listener works, because the example that I wrote doesn't show what I thought it was going to show.

I want to use a module (msfnode) which is a metasploit RPC client, so it connects through websockets.

I made a class and the constructor has this code:

this.clientmsf = new MetasploitClient({
            login : options.login || 'myLogin',
            password : options.password || 'myPassword'
        });
        this.clientmsf.on('connected',function(err,token) {
            if (err) throw err; 
        });

So I thought I could use the object "clientmsf" in other function of that class and it shows an error: error_message: 'Invalid Authentication Token'. THis is the code:

this.clientmsf.exec(['console.create'], function(err,r){
            consoleID = r.id;
            console.log(r);
        });

I think I have this error because I don't know all concepts of node.js so I will be very appreciate if someone helps me.

Thank you very much.

PD. This is an example of msfnode library:

var metasploitClient = require('metasploitJSClient');
var onConnect = function(err,token) {
    if (err) {
        console.log(err.error_message);
        process.exit(0);
    }
    metasploitVersion();
}
var metasploitVersion = function() {
    // Do not care about token, it will automaticaly
    // be added as the second arguments
    // The first value of the array is the function
    // you want to call. Full list is available
    // in metasploit remote api documentation
    var args = ['core.version'];
    client.exec(args,function(err,r) {
        if (err) return console.log('Error: '+err);
        console.log('-> Version: '+r);
    });
}
var client = new metasploitClient({
    login:'myLogin',
    password:'myPassword',
});
client.on('connected',onConnect);

Error:

{ error: true,
  error_class: 'Msf::RPC::Exception',
  error_string: 'Msf::RPC::Exception',
  error_backtrace: 
   [ 'lib/msf/core/rpc/v10/service.rb:148:in `process\'',
     'lib/msf/core/rpc/v10/service.rb:90:in `on_request_uri\'',
     'lib/msf/core/rpc/v10/service.rb:72:in `block in start\'',
     'lib/rex/proto/http/handler/proc.rb:38:in `call\'',
     'lib/rex/proto/http/handler/proc.rb:38:in `on_request\'',
     'lib/rex/proto/http/server.rb:363:in `dispatch_request\'',
     'lib/rex/proto/http/server.rb:297:in `on_client_data\'',
     'lib/rex/proto/http/server.rb:157:in `block in start\'',
     'lib/rex/io/stream_server.rb:48:in `call\'',
     'lib/rex/io/stream_server.rb:48:in `on_client_data\'',
     'lib/rex/io/stream_server.rb:192:in `block in monitor_clients\'',
     'lib/rex/io/stream_server.rb:190:in `each\'',
     'lib/rex/io/stream_server.rb:190:in `monitor_clients\'',
     'lib/rex/io/stream_server.rb:73:in `block in start\'',
     'lib/rex/thread_factory.rb:22:in `call\'',
     'lib/rex/thread_factory.rb:22:in `block in spawn\'',
     'lib/msf/core/thread_manager.rb:100:in `call\'',
     'lib/msf/core/thread_manager.rb:100:in `block in spawn\'' ],
  error_message: 'Invalid Authentication Token',
  error_code: 401 }

EDIT 2:

This is the code I checked:

clientmsf.on('connected',function(err,token) {
    if (err) throw err; 
    var consoleID;
    console.log('token:' + token);
    // should have connected by now
    clientmsf.exec(['console.list'], function(err,r){
        consoleID = r;
        console.log(r);
    });
    console.log (consoleID);
});

And this is what it shows:

token:[object Object]
undefined
{ consoles: [ { id: '0', prompt: 'msf > ', busy: false } ] }

Answer 1

Notice how in the sample code they do the work (metasploitVersion) only after connecting and getting a token.

var onConnect = function(err,token) {
    if (err) {
        console.log(err.error_message);
        process.exit(0);
    }
    // in the connect callback here - you have a token
    // only then call to do the work
    metasploitVersion();
}

Try moving your 'this.clientmsf.exec' code inside the connect callback function. If you have it outside that callback, it will execute before the connect is done.

I would also recommend that you log out the token inside that callback to ensure you're connected properly.

I'm suggesting something like:

var clientmsf = new MetasploitClient({
    login : options.login || 'myLogin',
    password : options.password || 'myPassword'
});

clientmsf.on('connected',function(err,token) {
    if (err) throw err; 

    console.log('token:' + token);
    // should have connected by now
    clientmsf.exec(['console.create'], function(err,r, token){
        consoleID = r.id;
        console.log(r);
    });
});