Nodejs MongoDB updating documents with asynchronous function - node.js

Question

I'm new to NodeJS and MongoDB. Is there a way to update a document using asynchronous functions in nodejs? I have a collection of websites with documents: _id, name and registrant. I want to insert a value in registrar using an asynchronous function. The function is a system call, and I just parse the output that I want. Running the code, the async function logs the information I want but does not store in the database. Any suggestions on how I can solve this? Thanks.
/*
* { _id: 53448014b15c693931000002,
* name: 'google.com',
* registrant: 'defaultval' } */
var MongoClient = require('mongodb').MongoClient;
var ObjectID = require('mongodb').ObjectID;
var id = '53448014b15c693931000002';
var domain = 'google.com';
MongoClient.connect('mongodb://127.0.0.1:27017/mydb', function(err, db) {
if (err) throw err;
var collection = db.collection('websites');
collection.findAndModify({_id:new ObjectID(id)},
{},
{$set: {registrant: test(domain, function (output) {
var t = output.split("\n");
for (var i = 0; i < t.length; ++i) {
if (t[i].indexOf("Registrant Organization:") != -1) {
console.log(t[i].substring(t[i].indexOf(":") + 2, t[i].length));//prints correct value, need this to store in registrant doc
return t[i].substring(t[i].indexOf(":") + 2, t[i].length);
}
}
})}},
{},
function(err, object) {
if (err) console.log(err.message);
else {
console.log(object);
}
db.close();
});
});
var test = function(domain, cb) {
var sys = require('sys');
var exec = require('child_process').exec;
var child = exec('whois ' + domain, function(error, stdout, stderr) {
cb(stdout);
});
}

Answer 1

Start one process on core:
var cluster = require('cluster')
, numCPUs = require('os').cpus().length
, windows = require('os').platform() == 'win32';
if(cluster.isMaster) {
// Fork workers.
for (var i = 0; i < numCPUs; i++) {
cluster.fork();
}
cluster.on('exit', function(worker, code, signal) {
console.log('worker ' + worker.pid + ' died');
});
return;
}
Create function to be async:
function mongodbDriverQuery(callback) {
collection.findOne({ id: getRandomNumber()}, function(err, world) {
callback(err, world);
});
}
http.createServer(function (req, res) {
// JSON response object
var hello = {message: "Hello, World!"};
var helloStr = "Hello, World!";
var path = url.parse(req.url).pathname;
// mysql on windows is not supported
if (windows && (path.substr(0, 3) == '/my' || path == '/update')) {
path = '/doesntexist';
}
switch (path) {
case '/mongodbdriver':
// Database Test
var values = url.parse(req.url, true);
var queries = values.query.queries || 1;
var queryFunctions = new Array(queries);
for (var i = 0; i < queries; i += 1) {
queryFunctions[i] = mongodbDriverQuery;
}
res.writeHead(200, {'Content-Type': 'application/json; charset=UTF-8'});
// and run it
async.parallel(queryFunctions, function(err, results) {
if (queries == 1) {
results = results[0];
}
res.end(JSON.stringify(results));
});
break;