Example NPM + Express + MongoDb

gistfile1.txt

//include express library
const express = require('express');
const app = express();

//include mongodb client library
const MongoDb = require('mongodb').MongoClient;

//declare the parameters to connect to MongoDB server and DB
const mongoDbUrl = 'mongodb://localhost:27017';
const mongoDbDatabaseName = 'rest-api';

const writeUserToDb = (req, res) => {
	
	MongoDb.connect(mongoDbUrl,(err,client) => {
		const db = client.db(mongoDbDatabaseName);
		const collection = db.collection('users');

		var myUsername = req.query.name;
		var myUser = { name: myUsername, role: 'admin' };

		collection.insert(myUser,(err,result) => {
			res.send("Object created: " + JSON.stringify(myUser) );
		});

		client.close();
	});

};

const readUsersFromDb = (req,res) => {

	MongoDb.connect(mongoDbUrl,(err,client) => {
		const db = client.db(mongoDbDatabaseName);
		const collection = db.collection('users');

		collection.find({}).toArray((err,docs) => {
			res.send(JSON.stringify(docs));
		});

		client.close();
	});

};

const readUserFromDb = (req,res) => {

	MongoDb.connect(mongoDbUrl,(err,client) => {
		const db = client.db(mongoDbDatabaseName);
		const collection = db.collection('users');

		var nameToSearch = req.query.name;

		collection.find({name: nameToSearch}).toArray((err,docs) => {
			res.send(JSON.stringify(docs));
		});

		client.close();
	});

};

const updateUserOnDb = (req,res) => {

	MongoDb.connect(mongoDbUrl,(err,client) => {
		const db = client.db(mongoDbDatabaseName);
		const collection = db.collection('users');

		var nameToSearch = req.query.nameToSearch;
		var nameToReplace = req.query.nameToReplace;

		var newUser = { name: nameToReplace, role: 'admin' };

		collection.update({name: nameToSearch},newUser);
		res.send("Updated");

		client.close();
	});

};

app.get('/writeUser',writeUserToDb);
app.get('/readUsers',readUsersFromDb);
app.get('/readUser',readUserFromDb);
app.get('/updateUser',updateUserOnDb);

app.get('/', (req, res) => {
	var input = req.query.name;
	res.send('L\'utente si chiama: '+input);
});

app.listen(3000, () => {
	console.log('Server ready'); 
});