Modernize phpblog: Migrate to PDO, OOP architecture, Docker, and session-based auth

[rlbisbe]

Overview

This PR modernizes the phpblog application by replacing deprecated MySQL functions with PDO, refactoring to object-oriented architecture, adding Docker support, and implementing secure session-based authentication.

Requirements Implemented

Security & Database Improvements

• ✅ Replaced deprecated mysql_ functions with PDO*: All database interactions now use PDO with prepared statements to prevent SQL injection vulnerabilities
  • Replaced mysql_connect, mysql_select_db, mysql_query, mysql_fetch_assoc, mysql_error throughout the codebase
  • Implemented prepared statements for all database queries

Configuration Management

• ✅ Externalized database configuration: Created separate configuration file that reads from environment variables
  • New config/config.php file for centralized configuration management
  • Supports environment variables for database host, username, password, and database name
  • Added .env.example file documenting all required environment variables

Authentication Enhancement

• ✅ Migrated to session-based authentication: Replaced cookie-based authentication with secure PHP sessions
  • Updated login.php to use $_SESSION instead of cookies
  • Updated logout.php to properly destroy sessions
  • All authenticated pages now validate sessions

Code Architecture

• ✅ Refactored to Object-Oriented PHP: Transformed procedural code into OOP design
  • Created src/Database.php class for connection management with singleton pattern
  • Created src/Posts.php class for post operations (CRUD operations)
  • Refactored backend.php to use new OOP structure
  • Updated all application files to use new classes

Dependency Management

• ✅ Added Composer support: Created composer.json with PSR-4 autoloading configuration
  • Configured autoloading for the PhpBlog namespace
  • Ready for future dependency management

Containerization

• ✅ Created Dockerfile: Sets up PHP 8.x environment with required extensions

  • Configured Apache with PHP 8.x
  • Installed pdo_mysql extension
  • Properly configured document root and permissions

• ✅ Created docker-compose.yml: Defines complete application stack

  • PHP application service with proper volume mounts
  • MySQL database service with persistent storage
  • Environment variable configuration
  • Network configuration for service communication

Documentation

• ✅ Added comprehensive documentation: Created README.md with setup and usage instructions
• ✅ Added initialization script: Created init.sql for database schema setup

Files Changed

New Files

• .env.example - Environment variable template
• .gitignore - Git ignore patterns for PHP projects
• Dockerfile - Container configuration for PHP application
• docker-compose.yml - Multi-container orchestration
• composer.json - Dependency and autoloading configuration
• config/config.php - Centralized configuration management
• src/Database.php - Database connection class
• src/Posts.php - Posts management class
• init.sql - Database initialization script
• README.md - Comprehensive setup and usage documentation

Modified Files

• backend.php - Refactored to use OOP and PDO
• index.php - Updated to use new Database and Posts classes
• login.php - Migrated to session-based authentication
• logout.php - Updated to destroy sessions properly
• admin/index.php - Updated to use new architecture
• admin/add_new_post.php - Updated to use PDO and OOP
• admin/new_post.php - Updated to use PDO and OOP

Testing

All existing functionality has been preserved:

• ✅ Viewing posts on the homepage
• ✅ User login/logout functionality
• ✅ Adding new posts (admin functionality)
• ✅ Post display and formatting

Deployment

To run the modernized application:

# Copy environment variables template
cp .env.example .env

# Edit .env with your configuration
# Then start the application
docker-compose up -d

The application will be available at http://localhost:8080

Breaking Changes

None - all existing functionality continues to work as before.

Dependencies

• PHP 8.x
• MySQL 5.7+
• Docker & Docker Compose (for containerized deployment)

Security Improvements

1. SQL injection protection through PDO prepared statements
2. Session-based authentication (more secure than cookies)
3. Environment-based configuration (credentials not in code)
4. Updated to modern PHP 8.x features