Epoch 5: Notification Service using HonoJS

Objectives

• Set up a lightweight microservice using HonoJS.
• Create REST API endpoints for receiving notification or event messages.
• Simulate event handling using HTTP POST requests.
• Prepare this service for asynchronous message queue integration in the next epoch.

1. Microservice Overview

• Service Name: notification-service
• Technology Stack: Node.js, Hono

2. Structure architechture

notification-service/
├── src/
│   └── index.js
├── .env
├── package.json

2.1. Project Setup

• Step 1: Initialize the Project

  mkdir notification-service
  cd notification-service
  npm init -y
  

• Step 2: Install Dependencies

  npm install hono dotenv
  

• Step 3: Project Structure: Create the following folders and files:

  mkdir controllers models routes middlewares
  touch server.js .env
  

2.2. Create the Notification API

• src/index.js

import { Hono } from 'hono';
import { logger } from 'hono/logger';
import { cors } from 'hono/cors';

const app = new Hono();

// Middleware
app.use('*', logger());
app.use('*', cors());

// POST /notify
app.post('/notify', async (c) => {
  const body = await c.req.json();
  console.log('New notification received:', body);

  return c.json({ message: 'Notification logged.' }, 200);
});

export default app;

2.3. Run the Server

• Update your package.json:

  "scripts": {
  "dev": "node --watch src/index.js"
  }
  

• Then run:

  npm run dev
  

  By default, Hono runs on port 3000. You can also customize this if needed.

3. Testing with Postman

• Endpoint: POST http://localhost:3000/notify
• Request Body:

  {
  "type": "order_created",
  "message": "New order #01234 created for user ID 789",
  "timestamp": "2025-07-17T10:00:00Z"
  }
  

• Response:

{
  "message": "Notification logged."
}

• Console Output:

  New notification received: {
  type: 'order_created',
  message: 'New order #01234 created for user ID 789',
  timestamp: '2025-07-17T10:00:00Z'
  }