index.js

#!/usr/bin/env node

var http = require('http');
var url = require('url');
var crypto = require('crypto');
var Q = require('q');
var MongoClient = require('mongodb').MongoClient;

var port = process.env.PORT || 5000;
var mongo_uri = process.env.MONGO_URI || "mongodb://admin:admin@localhost:27017";
var db = null;

var server = http.createServer(function(req, res) {
  if (req.method == 'GET' && url.parse(req.url).pathname == '/create') {
    username = crypto.randomBytes(12).toString('hex');
    password = crypto.randomBytes(12).toString('hex');
    dbname = crypto.randomBytes(12).toString('hex');
    new_db_conn = db.db(dbname);
    new_db_conn.addUser(username, password, {roles: [ { role: "readWrite", db: dbname } ]},function(err, result) {
        if (err) {
            console.error("Could not create user with name " + username + "; password: " + password + " for database " + dbname + "!\n" + err);
            res.writeHead(500, {"Content-Type": "text/plain"});
            res.end("Error! Could not create user and database in mongodb!\n");
        } else {
            mongo_conn_string = "mongodb://" + username + ":" + password + "@" + url.parse(mongo_uri).host + "/" + dbname;
            res.writeHead(200, {"Content-Type": "text/plain"});
            res.end(mongo_conn_string + "\n");
        }
    });
  } else {
    res.statusCode = 404;
    res.end("Only /create URL is supported currently");
  }
});

function init(callback) {
  try {
    // Use connect method to connect to the Server 
    MongoClient.connect(mongo_uri, function(err, _db) {
        if (err) {
            callback(err);
        }
        db = _db;
        console.log("Connected correctly to MongoDB server.");
    });
    callback(null);
  } catch(err) {
    callback(err);
  }
}

server.on('close', function() {
    db.close();
    console.log('Disconnected from MongoDB');
    console.log('Stopping server ...');
});

process.on('SIGINT', function() {
  server.close();
});

init(function start(err){
  if (err) {
    console.error("Error during starting the app: " + err.message);
    process.exit(1);
  } else {
    server.listen(port);
    console.log("Server successfully started on port " + port);
  }
});