Connecting to MongoDB with Mongoose in Node.js: A Guide

As I’m getting acquainted with Mongoose, I’m facing some confusion regarding connecting to a particular database and collection in my cluster. Although the setup seems fine, I observed a few points that might have been overlooked in app.js.


Question:

The class responsible for controlling the product can be found in the product.controller.js file.

const Product = require('../models/product.model');
//Simple version, without validation or sanitation
exports.test = function (req, res) {
    res.send('Greetings from the Test controller!');
};
exports.product_create = function (req, res) {
    const product = new Product(
        {
            name: req.body.name,
            price: req.body.price
        }
    );
    product.save(function (err) {
        if (err) {
            return next(err);
        }
        res.send('Product Created successfully')
    })
};

models/product.model.js

var mongoose = require('mongoose');
const Schema = mongoose.Schema;
const ProductSchema = new Schema({
    name: {type: String, required: true, max: 100},
    price: {type: Number, required: true},
});
exports.product_details = function (req, res) {
    Product.findById(req.params.id, function (err, product) {
        if (err) return next(err);
        res.send(product);
    })
};
exports.product_delete = function (req, res) {
    Product.findByIdAndRemove(req.params.id, function (err) {
        if (err) return next(err);
        res.send('Deleted successfully!');
    })
};
exports.product_update = function (req, res) {
    Product.findByIdAndUpdate(req.params.id, {$set: req.body}, function (err, product) {
        if (err) return next(err);
        res.send('Product udpated.');
    });
};
router.put('/:id/update', product_controller.product_update);
// Export the model
module.exports = mongoose.model('Product', ProductSchema);

This JavaScript file is utilized for routing purposes within the product.

const express = require('express');
const router = express.Router();
// Require the controllers WHICH WE DID NOT CREATE YET!!
const product_controller = require('../controllers/product.controller');
router.post('/create', product_controller.product_create);
// a simple test url to check that all of our files are communicating correctly.
router.get('/test', product_controller.test);
router.put('/:id/update', product_controller.product_update);
router.delete('/:id/delete', product_controller.product_delete);
module.exports = router;

app.js this is the app.js

const express = require('express');
const bodyParser = require('body-parser');
const product = require('./routes/product.route'); // Imports routes for the products
const app = express();
// Set up mongoose connection on mongoAtlas
//https://codeburst.io/writing-a-crud-app-with-node-js-and-mongodb-e0827cbbdafb
const mongoose = require('mongoose');
const dev_db_url = 'mongodb://someuser:[email protected]:23619/productstutorial';
const mongoDB = process.env.MONGODB_URI || dev_db_url;
mongoose.connect(mongoDB);
mongoose.Promise = global.Promise;
const db = mongoose.connection;
db.on('error', console.error.bind(console, 'MongoDB connection error:'));
app.use('/products', product);
app.listen(3000,function () {
    console.log("Server listen on port: 3000");
});
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({extended: false}));
app.use('/products', product);

Kindly include the script “start”: “node app.js” in the project’s code. With this, you can immediately use and modify the code to perform operations such as updating, inserting, and deleting data.


Solution:

The arrangement appears satisfactory, but I have observed a couple of omissions in app.js. I am confident that the below altered setup will establish a reliable connection to your MongoDB.

const mongoose = require('mongoose');
const express = require('express');
var cors = require('cors');
const bodyParser = require('body-parser');
const product = require('./routes/product.route'); // Imports routes for the products
const API_PORT = 3000;
const app = express();
app.use(cors());
// Set up mongoose connection on mongoAtlas
//https://codeburst.io/writing-a-crud-app-with-node-js-and-mongodb-e0827cbbdafb
const dev_db_url = 'mongodb://someuser:[email protected]:23619/productstutorial';
// connects our back end code with the database
mongoose.connect(process.env.MONGODB_URI || dev_db_url, { useNewUrlParser: true });
let db = mongoose.connection;
db.once('open', () => console.log('connected to the database'));
// checks if connection with the database is successful
db.on('error', console.error.bind(console, 'MongoDB connection error:'));
// bodyParser, parses the request body to be a readable json format
app.use(bodyParser.urlencoded({ extended: false }));
app.use(bodyParser.json());
// append /api for our http requests
app.use('/product', product);
// launch our backend into a port
app.listen(API_PORT, () => console.log(`LISTENING ON PORT ${API_PORT}`));

Frequently Asked Questions