NodeJS/Express GET exit status of external application - node.js

Question

I am pretty new to NodeJS and this is my first time with Express 4, I'm trying to build a simple RESTful front-end around a command-line application. There will ultimately only be one GET and one POST necessary, with the POST handling about 3 or 4 different parameters. The GET should call the command-line application with all default parameters, which is basically just a status check and return the exit status upon completion. The POST will pass along POST parameters on the commandline. I know that this basically calls for an asynchronous call, like child_process.execFile(), but I can't seem to figure out how to actually return the response from within the callback function.
This is the tutorial I used as a starting point, omitting the mongoose dependency, because I have no need for MongoDB, so I basically just followed it up to the point where you start the server. At this point, I'm pretty lost. I always hate writing async code...
var express = require('express'); // call express
var app = express(); // define our app using express
var bodyParser = require('body-parser');
var child_process = require('child_process');
app.use(bodyParser.urlencoded({ extended: true }));
app.use(bodyParser.json());
var port = process.env.PORT || 8080; // set our port
var router = express.Router(); // get an instance of the express Router
router.get('/', function(req, res) {
res.json({ message: 'hooray! welcome to our api!' });
});
router.get('/myapp/status', function(req, res) {
console.log(req.user);
child_process.execFile(
'casperjs',
['myfile.js', '--cmd="Status"', '--user="myuser"', '--pass="#mypass"'],
null,
function(response) {
// ???
}, res);
});
app.use('/api', router);
app.listen(port);
console.log('Magic happens on port ' + port);

Answer 1

You can try the following:
router.get('/myapp/status', function(req, res) {
console.log(req.user);
child_process.execFile(
'casperjs', //command
["myfile.js --cmd=Status --user=myuser --pass=#mypass"], // args
function(err, stdout, stderr) { //callback
if (err) {
return res.status(500).send(err);
}
res.send(stdout); // to send response to client
});
});