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Impossible to create users (or custom-based roles) in Mongo on server NodeJS

I am trying to create users on my database directly from our Express server, using Mongo 3.4 for the database. Here is the code for the server for now:
var express = require('express');
var bodyParser = require('body-parser');
var app = express();
app.use(bodyParser.urlencoded({ extended: true }));
app.use(bodyParser.json());
var MongoClient = require('mongodb').MongoClient;
var url = 'mongodb://mongo:27017/myDb';
var dbvotes = "collection1";
var dbusers = "collection2";
//Functions for users
app.post('/newUser', function(req, res, db) {
MongoClient.connect(url, function(err, db){
//Ecriture dans la base user
db.collection(dbusers).insertOne( {
"name" : req.body.name,
"surname" : req.body.surname,
"username" : username,
"password" : "pasadmin",
});
//Creation of the user in the DB
db.createUser( { 'user': username, 'pwd': "pasadmin", roles: [] });
db.close();
});
console.log("Inserted a new user in the database.");
res.send("User added. Click precedent to add a new user.");
});
However, whenever the client tries to insert a new user, it is effectively created in the user collections, but not as a user of the database as I get the following error: TypeError: db.createUser is not a function
web_1 | at /app/app.js:47:6.
I have tried to user db.addUser instead, however, this is deprecated since Mongo 2.6 and not working either, and db.adminCommand serves the same error, db.adminCommand is not a function. Before that, I struggled to create custom roles in the database with Node and decided to do it via the Mongo shell as well, but it's not an option when it comes to adding user 1 by 1 in the database.
When I use these functions in the Mongo shell, the commands are working, so I suppose it comes from the way I implemented Mongo within the server (via Docker), or due to some limitations with Javascript. Any idea what could it be?
Thanks in advance to the community!

The proper command would be:
db.addUser( username, password, { roles: [ role ] } );
Where role is some MongoDB role. More info can be found from the source file. It can also be an object in the formation of { role: <string>, db: <string> }, where role is a MongoDB role and db is the string name of the database.
You can also use db.admin().addUser. This would be the logical choice if the user has access to multiple databases or you want a central location of your users.
However, I can't imagine it's a good idea to add system users from your application unless you're developing an actual administrative tool. Normal "users" added to a database would be in your own users collection. A system user is someone who has direct access to your database.

Real time notifications node.js

I'm developing a calendar application with Node.js, express.js and Sequelize.
The application is simple, you can create tasks in your calendar, but you can also assign some tasks to others users of the system
I need to create a notification system with socket.io, but I don't have experience with websockets. My big doubt is how can I make my server send a notification to the user that you assign the task?
My ports configurations is on a folder called bin/www, my express routes are defined on a file called server.js
Any Idea?

I want to introduce you to ready to use backend system that enables you to easily build modern web applications with cool functionalities:
Persisted data: store your data and perform advanced searches on it.
Real-time notifications: subscribe to fine-grained subsets of data.
User Management: login, logout and security rules are no more a burden.
With this, you can focus to your main application development.
You can look at Kuzzle, wich is one project I working on:
First, start the service:
http://docs.kuzzle.io/guide/getting-started/#running-kuzzle-automagically
Then in your calendar application you can the javascript sdk
At this point you can create a document:
const
Kuzzle = require('kuzzle-sdk'),
kuzzle = new Kuzzle('http://localhost:7512');
const filter = {
equals: {
user: 'username'
}
}
// Subscribe every changes in calendar collection containing a field `user` equals to `username`
kuzzle
.collection('calendar', 'myproject')
.subscribe(filter, function(error, result) {
// triggered each time a document is updated/created !
// Here you can display a message in your application for instance
console.log('message received from kuzzle:', result)
})
// Each time you have to create a new task in your calendar, you can create a document that represent your task and persist it with kuzzle
const task = {
date: '2017-07-19T16:07:21.520Z',
title: 'my new task',
user: 'username'
}
// Creating a document from another app will notify all subscribers
kuzzle
.collection('calendar', 'myproject')
.createDocument(task)
I think this can help you :)
Documents are served though socket.io or native websockets when available
Don't hesitate to ask question ;)

As far as I can understand you need to pass your socket.io instance to other files, right ?
var sio = require('socket.io');
var io = sio();
app.io = io;
And you simply attach it to your server in your bin/www file
var io = app.io
io.attach(server);
Or what else I like to do, is adding socket.io middleware for express
// Socket.io middleware
app.use((req, res, next) => {
req.io = io;
next();
});
So you can access it in some of your router files
req.io.emit('newMsg', {
success: true
});

Error Running MongoDB Script on OpenShift Gear

I wrote a database population script (in JavaScript) so that I could easily run it on my local and on the server. I want to run it from the command line so that all I have to do is push it to the server/gear and execute it. The script runs fine on my local, but when I try to run it on the OpenShift gear it gives the following error:
MongoDB shell version: 2.4.9
connecting to: 127.XX.XXX.X:27017/admin
Sat Sep 12 12:20:25.979 count failed: { "ok" : 0, "errmsg" : "unauthorized" }
at src/mongo/shell/query.js:180
failed to load: ./Create.js
I'm trying to execute the command:
[xxxxxx-xxxxxx.rhcloud.com scripts]\> mongo ./Create.js
I have included the innards of my file. I left out all the document creation stuff. Just know I added document to an array.
// Switch to the DB we want
var connection;
try {
// Try to connect to local first
connection = new Mongo();
}
catch(err) {
// If error, connect to OpenShift server
connection = new Mongo('127.XX.XXX.X:27017');
}
db = connection.getDB('xxxxxxx');
// Create array to store documents
var newDocs = [];
...
// Documents are added to newDocs here
...
// If any new documents exist, insert them
if(newDocs.length) {
var bulk = db.xxxxxxx.initializeUnorderedBulkOp();
newDocs.forEach(function (doc) {
bulk.insert(doc);
});
bulk.execute();
print('NEW DOCS INSERTED');
}
else {
print('NO NEW DOCS');
}

Looks like you are missing your username/password to connect to your mongodb database on openshift? look at the error you got "unauthorized..."

I used db.auth('username', 'password'); to authenticate. Ultimately, I added a variable to the script to track if I was running the script locally or on the server. Then I used a variable for the password so that I wouldn't have the DB password just hanging out in the script. I pass the password in from the command line with the --eval option. Here is the altered head of the script:
// Switch to the DB we want
var connection;
var isLocal = true;
try {
// Try to connect to local first
connection = new Mongo();
}
catch(err) {
// If error, connect to OpenShift server
connection = new Mongo('127.XX.XXX.X:27017');
isLocal = false;
}
db = connection.getDB('xxxxxxx');
if(!isLocal) {
// If on server, authenticate
db.auth('username', password);
}
// Create array to store documents
var newDocs = [];
Then, to run the script from the command line on the server, I use the following:
mongo --eval "var password = 'xxxxxxx';" Create.js

Firebase push notifications - node worker

I need to send iOS push notifications to user whenever a certain child is added to a Firebase path.
I was thinking, that the best way to do that, would be to make a Node.js worker on Heroku, that would listen for changes and send a notification using Urban Airship.
I'm not sure what the best way is to listen for changes on Firebase from a Node.js worker on Heroku is. I'm not that familiar with heroku workers and Node.js.
Can anyone give me some pointers? Examples?

Sending push notifications with Firebase and node-apn is easy:
var apn = require("apn");
var Firebase = require("firebase");
// true for production pipeline
var service = new apn.connection({ production: false });
// Create a reference to the push notification queue
var pushRef = new Firebase("<your-firebase>.firebaseio.com/notificationQueue");
// listen for items added to the queue
pushRef.on("child_added", function(snapshot) {
// This location expects a JSON object of:
// {
// "token": String - A user's device token
// "message": String - The message to send to the user
// }
var notificationData = snapshot.val();
sendNotification(notificationData);
snapshot.ref().remove();
});
function sendNotification(notificationData) {
var notification = new apn.notification();
// The default ping sound
notification.sound = "ping.aiff";
// Your custom message
notification.alert = notificationData.message;
// Send the notification to the specific device token
service.pushNotification(notification, [notificationData.token]);
// Clean up the connection
service.shutdown();
}
For hosting this script, you won't be able to use a PaaS like Heroku. They tend to kill idle sockets. Instead you'll have to use a virtual machine.
Google Cloud Platform has a Node.js launcher that works well.

node.js - how to switch a database in mongodb driver?

I'm new to this stuff and just stuck in the middle of nowhere. Am using node-mongodb-native and am in need to switch to another database (after authentication against admin db). I googled and found this topic where the creator of library recommends to keep a connection for each db in a hash. So my question is - how do I accomplish it?

Just create different database connections and store them in an object.
var dbConnections = {};
var dbConnections.authDb = new Db('adminDb', server, {});
dbConnections.authDb.authenticate(username, password);
var dbConnections.otherDb = new Db('otherDb', server, {});
Does that make sense?

There's an example hidden in the MongoDB driver docs under Db:
[...]
MongoClient.connect('mongodb://localhost:27017/test', function(err, db) {
[...]
// Reference a different database sharing the same connections
// for the data transfer
var secondDb = db.db("integration_tests_2");
// Fetch the collections
var multipleColl1 = db.collection("multiple_db_instances");
var multipleColl2 = secondDb.collection("multiple_db_instances");
[...]
});