Symfony Pricing Engine

A demonstration project showcasing a flexible and extensible pricing engine built with Symfony. It provides a REST API to manage products and a /checkout endpoint that calculates the final cart price by applying different discount strategies.

Each product has a base price and can have one of the following discount strategies applied:

• Fixed Discount
• Percentage Discount
• Buy One Get One Free

This project highlights clean code, modular design, and clear API structure, making it easy to extend with additional business rules or discount strategies.

Requirements

To run this project, you need:

• PHP 8.4 or higher
• Composer
• Symfony CLI
• Docker & Docker Compose

Installation & Setup

1. Copy the environment file:

   cp .env.example .env.local

   Then add your API token inside. You can generate a token with:

   php -r "echo bin2hex(random_bytes(32));"

2. Install PHP dependencies:

   composer install

3. Start the database with Docker:

   docker-compose up -d

4. Run database migrations: For the main database:

   php bin/console doctrine:migrations:migrate

   For the test database:

   php bin/console doctrine:database:create --env=test
   php bin/console doctrine:migrations:migrate --env=test

5. Start the Symfony development server:

   symfony server:start

   The API will be accessible at:

   http://localhost:8000/api/v1
   

API

Base URL

http://localhost:8000/api/v1

Available endpoints

Method	Endpoint	Description
GET	/products	List all products
GET	/products/{id}	Retrieve a single product
POST	/products	Create a new product
PUT	/products/{id}	Update an existing product
DELETE	/products/{id}	Delete a product
POST	/checkout	Calculate the total cart price with discounts

Authentication

All API requests require a token in the Authorization header:

Authorization: Bearer your_api_token

The token should match the one set in your .env.local.

OpenAPI Documentation

The API is documented using OpenAPI 3.2.0. Full details are available in the openapi.yaml file.

Postman Collection

Postman collection and environment files are saved in the postman/ directory. You can import them in Postman to quickly start testing the API.

Tests

The project uses PHPUnit for unit and integration tests, with a separate test database to avoid interfering with the development database.

Run the tests using Composer:

composer test

Tests automatically use the .env.test file and a dedicated database named app_test.

Code Quality Tools

The project uses the following tools to ensure clean, maintainable code, catch errors early, and keep the codebase consistent:

• PHP_CodeSniffer for PSR-12 coding standards:

composer phpcs
composer phpcbf

• PHPStan for static analysis:

composer phpstan

Continuous Integration

This project uses GitHub Actions to automatically run tests, static analysis, and generate code coverage on every push or pull request.

• The .github/workflows/tests.yml workflow runs PHPUnit with Xdebug to collect code coverage, which is uploaded to Codecov for visualization and badge updates.
• The .github/workflows/static-analysis.yml workflow runs PHPStan to check for type errors and potential issues.

Architecture

Separation of Persistence Layer

The project separates persistence from business logic. Doctrine and Symfony entities are used solely for database interactions, while the application uses its own domain models and value objects for core business logic. This approach ensures a clean architecture, easier testing, and better maintainability.

Caching

Doctrine cache is enabled in the production environment to improve performance. A production-ready system could also leverage HTTP-level caching (e.g., Cache-Control headers) for additional performance gains, though it was not implemented in this project.

Author

Elias Gasparis

License

This project is licensed under the MIT License. See the LICENSE file for details.