Tax Calculator

This repository contains a Tax Calculator solution, designed as an enterprise-scale application using React.js, PHP 8.3, and API Gateway and microservice architecture. It calculates UK Income Tax based on defined tax bands and offers an intuitive user interface for tax calculation.

Project Structure

• Frontend (React.js): Located in the frontend/tax-frontend directory, the frontend allows users to input their gross salary and displays the tax results.

  • URL: http://127.0.0.1:3000/

• API Gateway: Manages the communication between the frontend and the backend services. It routes the requests to appropriate microservices.

  • URL: http://127.0.0.1:8080/

• Backend Microservices:

  • Reports Service (backend/reports-service): Provides tax calculation reports.
    • URL: http://127.0.0.1:8002/ -- Not pushed because is a work in progress
  • Tax Service (backend/tax-service): Calculates taxes based on UK tax bands.
    • URL: http://127.0.0.1:8001/

Components Used

Frontend

• React.js 18.3.1: Main library for building the UI.
• Node: v20.3.0
• Npm: 9.6.7
• React Router DOM: For navigation and routing.
• Axios: For making HTTP requests to the backend services.
• Tailwind CSS: Used for styling the application.

Backend (PHP Services)

• PHP 8.3: Backend logic is implemented using modern PHP.
• PSR-4 Autoloading: Follows PSR-4 for autoloading classes.
• Guzzle HTTP: Used in the API gateway for making HTTP requests.
• PHPUnit: For unit testing the backend services.

Setup Instructions

Prerequisites

Ensure that you have the following installed on your machine:

• Node.js and npm (for the frontend)
• PHP 8.3 (for the backend microservices)
• Composer (for managing PHP dependencies)

Steps

1. Clone the repository:

   git clone https://github.com/Raducu89/tax-calculator.git
   cd tax-calculator
   

2. Install Frontend dependencies:

   cd frontend/tax-frontend
   npm install
   

3. Install Backend dependencies: For tax-service run the following command. reports-service is a work in progress.

   composer install
   

4. Import the database:

5. Update the .env file:

   DB_HOST=localhost
   DB_NAME=tax_service
   DB_USERNAME=
   DB_PASSWORD=
   

6. Start the frontend:

   npm start
   

7. Start the API Gateway:

   php -S 127.0.0.1:8080
   

8. Start the backend service (tax_service):

   php -S 127.0.0.1:8001 -t public
   

9. Access the Application: Open your browser and go to http://127.0.0.1:3000/ to interact with the frontend.

TODO

• Add Redis for Caching: Implement Redis to store frequently accessed data and reduce API response times.
• Rate Limiting: Integrate rate limiting in the API gateway to prevent abuse.
• Load balancer
• CSRF Protection: Secure the frontend against CSRF attacks, especially for form submissions.

Testing

Go to backend/tax_service and run ./vendor/bin/phpunit --testdox