I’m building a Koa.js server and need to connect to MongoDB to store and retrieve data. Here is how to do it with some simple steps:
Step 1: Connect the database before Koa app initialised
const initDB = require('./database');
initDB();
const app = new Koa();Inside the database.js, import mongoose. You will need to npm install -save mongoose as well. It is an Object Data Modeling (ODM) library.
const mongoose = require('mongoose');
import { connexionString } from './conf/app-config';
const initDB = () => {
mongoose.connect(connexionString);
mongoose.connection.once('open', () => {
console.log('connected to database');
});
mongoose.connection.on('error', console.error);
}
module.exports = initDB;And the create the config of your connection string:
export const connexionString = 'mongodb+srv://'+secret.mongodb.username+':'+secret.mongodb.password+'@xxxxxx.mongodb.net/test?retryWrites=true&w=majority';You may run a local mongodb or you can use MongoDB Altas and run it on AWS cloud. Then you would get the connection string to put inside your config file.
Step 2: Create a schema in Koa
For example, we create a user schema inside /models/users.js
const mongoose = require('mongoose');
const Schema = mongoose.Schema;
const UserSchema = new Schema({
username: String,
email: String,
picture: String });
module.exports = mongoose.model('User', UserSchema);Step 3: Create a service to query the data
For example, we have a /service/user.service.js
import User from '../models/users';
export const getUserFromDb = async (username) => {
const data = await User.findOne({username: username})
return data;
};
export const createUserInDb = async (user) => {
var newUser = new User(user);
newUser.save();
return user; }Step 4: Call the service in Koa controller
For example, we have a /controller/user.controller.js
import { getUserFromDb } from '../service/user.service';
import { createUserInDb } from '../service/user.service';
static async getUser(ctx) {
const user = await getUserFromDb(ctx.query.username);
ctx.body = user;
}
static async registerUser(ctx) {
const user = await createUserInDb(ctx.request.body);
ctx.body = user;
}Finally, you can register the route using the controller and you can see the data being stored in the database. Let me know if you have any questions.