Spring Boot REST API with Frontend

Table of Contents

• Project Overview
• Backend
• Frontend
• Deployment Workflow (GitHub Actions)
• Systemd Service: api-test.service
  • Service Definition
  • Installation & Management
  • Managing the Service

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Project Overview

This project consists of a Spring Boot 3.3.0 REST API backend and a static HTML/JS frontend UI. The API serves stored messages from a MariaDB database and is secured with HTTP Basic Authentication.

• Backend: A Spring Boot REST API that provides endpoints to retrieve stored messages. It uses Spring Data JPA for database interactions with MariaDB. Security is enforced through Spring Security using HTTP Basic Authentication, meaning every API request must include valid credentials. The primary endpoint (/api/hello) fetches all stored messages.
• Frontend: A static HTML/JS app that consumes the API and displays responses.
• Deployment: Managed via GitHub Actions, with the backend running as a systemd service.

Visit the frontend at https://api-test.intellect37.com/

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Backend

The backend is a Spring Boot application that exposes API endpoints and interacts with a MariaDB database.

Endpoints

Method	Endpoint	Description	Authentication
GET	/api/hello	Returns all messages from the database.	Required

Persistence Layer

• HelloEntity.java: Defines the database table schema.
• HelloRepository.java: Manages data access using Spring Data JPA.
• Database Configuration (application.properties):

  spring.datasource.url=jdbc:mariadb://localhost:3306/spring_boot_api_test
  spring.datasource.username=[username]
  spring.datasource.password=[password]

Security

• Authentication: HTTP Basic Authentication.
• Configured in WebSecurityConfiguration.java:
  • Requires authentication for all endpoints.
  • Uses stateless session management.
• Default Credentials (for local testing):

  spring.security.user.name=admin
  spring.security.user.password=password

Frontend

The frontend is a static HTML/JavaScript app that interacts with the backend API.

Components

• index.html:
  • Displays a button to fetch data from the API.
  • Shows API responses inside a <pre> tag.
• app.js:
  • Fetches data from https://api-test.intellect37.com/api/hello.
  • Uses Basic Authentication (admin:password).
  • Displays the response as formatted JSON.

  fetch('https://api-test.intellect37.com/api/hello', {
      method: 'GET',
      headers: {
          'Authorization': 'Basic ' + btoa('admin:password')
      }
  })
  .then(response => response.json())
  .then(data => console.log(data));

• app.css:
  • Styles the displayed JSON output

Deployment Workflow (GitHub Actions)

The GitHub Actions workflow automates deployment when changes are pushed to the main branch.

Workflow Steps

1. Build Backend:
   • Uses Maven to package the Java application.
2. Deploy Backend:
   • Transfers the JAR file to /srv/api-test/api-test.jar on the server.
   • Restarts the api-test.service.
3. Deploy Frontend:
   • Syncs frontend files to /var/www/intellect37.com/api-test/.

Deployment Commands

• Backend JAR Deployment:

  scp api-test.jar user@server:/srv/api-test/api-test.jar
  ssh user@server "sudo systemctl restart api-test.service"

• Frontend Deployment

  rsync -avz frontend/ user@server:/var/www/intellect37.com/api-test/

Systemd Service: api-test.service

The backend runs as a systemd service, ensuring it starts on boot and automatically restarts if it crashes.

Service Definition (/etc/systemd/system/api-test.service)

[Unit]
Description=API Test Spring Boot Application
After=network.target

[Service]
User=[username]
ExecStart=/usr/bin/java -jar /srv/api-test/api-test-0.0.1-SNAPSHOT.jar
SuccessExitStatus=143
Restart=on-failure
RestartSec=10

[Install]
WantedBy=multi-user.target

Managing the Service

Command	Description
sudo systemctl start api-test	Start the service manually.
sudo systemctl stop api-test	Stop the service.
sudo systemctl restart api-test	Restart the service.
sudo systemctl enable api-test	Enable the service to start on boot.
sudo systemctl disable api-test	Disable automatic start on boot.

How It Works

• Runs the backend API as a background process using java -jar.
• Restarts automatically if it fails, waiting 10 seconds before retrying.
• Loads on system boot, ensuring the API is always available.

Final Notes

This setup ensures full automation of deployment and service reliability on the production server. The backend API will always restart in case of failure and will automatically start on server reboot.