Install Tools

NodeJS: https://nodejs.org/en

Code Editor: VS Code

Request Track: Postman

Set up MERN Project

• Open project explorer on VS Code.
• Run Terminal.

Backend Set up

• Create folder "backend": touch backend.

• Execute cd backend and npm init, then press Enter until the end.

• Install packages: npm i express mongoose dotenv bcryptjs jsonwebtoken nodemon nodemailer multer cron socket.io.

• Define this argument in package.json

  "type": "module"

Note:

Package	Description
Mongoose	a JavaScript object-oriented programming library that creates a connection between MongoDB and Node.js.
Nodemon	automatically restarts the node application when file changes in the directory are detected.
JSON Web Token	JWT is a way for creating data with optional signature and/or optional encryption.
Bcryptjs	a library that supports hashing passwords.
Multer	a module that support uploading files.
Cron Job	automatically sends GET requests to keep the site in an active state at all times after deployment.
Socket.IO	a module supporting realtime server.

Frontend Set up

• Create folder "frontend": touch frontend.
• Execute cd frontend and npm create vite@latest.
• Project name: ., then press Enter.
• Select a framework: React.
• Select a variant: JavaScript.
• Run npm i react-router-dom.
• Install Bootstrap package: npm install react-bootstrap bootstrap.

Deployment

• Rename the frontend folder to "client".
• Move the whole folder "client" to the folder "backend".
• Then, move all files from the "backend" to the external.
• Delete the empty folder "backend".

Modify "server.js" with context recognition for absolute links

import express from "express";
import mongoose from "mongoose";
import { postsRoutes } from "./routes/postsRoutes.js";
import { usersRoutes } from "./routes/usersRoutes.js";
import path from "path";
import { fileURLToPath } from "url";

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

const app = express();

app.use(express.json());

app.use("/api/posts", postsRoutes);
app.use("/api/users", usersRoutes);

app.use(express.static(path.join(__dirname, "/client/dist")));
app.get("*", (req, res) =>
  res.sendFile(path.join(__dirname, "/client/dist/index.html"))
);
mongoose
  .connect(process.env.DB_URI, { dbName: "demo_db" })
  .then(() => {
    console.log("Successfully connect to DB");
    app.listen(4000, () => console.log("Listening at 4000"));
  })
  .catch((err) => console.log(err));

File "cron.js"

import cron from "cron";
import https from "https";

const URL = "https://food-app-api-demo.onrender.com";

const job = new cron.CronJob("*/14 * * * *", function () {
  https
    .get(URL, (res) => {
      if (res.statusCode == 200) {
        console.log("GET request sent successfully");
      } else {
        console.log("GET request failed", res.statusCode);
      }
    })
    .on("error", (e) => {
      console.error("Error while sending request", e);
    });
});

export default job;

// CRON JOB EXPLANATION:
// Cron jobs are scheduled tasks that run periodically at fixed intervals or specific times
// send 1 GET request for every 14 minutes

// Schedule:
// You define a schedule using a cron expression, which consists of five fields representing:

//! MINUTE, HOUR, DAY OF THE MONTH, MONTH, DAY OF THE WEEK

//? EXAMPLES && EXPLANATION:
//* 14 * * * * - Every 14 minutes
//* 0 0 * * 0 - At midnight on every Sunday
//* 30 3 15 * * - At 3:30 AM, on the 15th of every month
//* 0 0 1 1 * - At midnight, on January 1st
//* 0 * * * * - Every hour

Add these to server.js

import job from "./utils/cron.js";
job.start();

Add building script to package.json

"build": "npm install --prefix ./client && npm run build --prefix ./client && npm install"

To prepare for deployment, delete these files/folders which will be automatically installed by the script above to reduce size (optional):

• folder "dist".
• folder "node modules".
• package-lock.json.

Fill the environment variables which are taken from the ".env" file.

MongoDB Atlat Setup

• Network Access -> Delete IP -> Add IP Address -> Allow anywhere