Modernize phpblog: PDO migration, environment-based configuration, and security enhancements

[rlbisbe]

Overview

This PR modernizes the phpblog application to align with current PHP best practices and security standards while maintaining all existing functionality.

Requirements Implemented

🔒 Security Improvements

• Replaced deprecated mysql_ functions with PDO* for database access using prepared statements to prevent SQL injection attacks
• Implemented proper input validation and sanitization across all user inputs
• Added password hashing with PHP's password_hash() and password_verify() functions
• Removed hardcoded database credentials from source code

⚙️ Configuration Management

• Environment-based configuration using .env file for sensitive data
• Created .env.example template for easy setup
• Added .gitignore to prevent committing sensitive files

📦 Dependency Management

• Created composer.json with appropriate PHP version constraints (>=7.4)
• Added vlucas/phpdotenv for environment variable management
• Defined autoloading for the new src/ directory structure

🏗️ Code Structure & Architecture

• Separated concerns with dedicated classes:
  • Config: Centralized configuration management
  • Database: PDO connection management with connection pooling
  • Post: Blog post operations (CRUD)
  • Auth: Authentication and session management
• Improved error handling with try-catch blocks and proper exception handling
• Added comprehensive documentation for all classes and methods

📄 Documentation

• NEW: README.md - Complete setup and usage guide
• NEW: QUICKSTART.md - Quick installation instructions
• NEW: MIGRATION.md - Migration guide from old to new version
• NEW: SECURITY.md - Security best practices and considerations
• NEW: CHANGES.md - Detailed changelog of all modifications
• NEW: POST_INSTALLATION_CHECKLIST.md - Post-deployment verification steps

🛠️ Additional Tools

• generate_password.php - Helper script for generating secure password hashes
• setup_db.sql - Database initialization script
• test_basic.php - Basic connectivity and configuration test script

Key Changes

Database Layer

• All database operations now use PDO with prepared statements
• Implemented proper connection error handling
• Added support for connection reuse

Authentication System

• Modernized login system with secure password verification
• Enhanced session management
• Added CSRF protection considerations in documentation

Blog Post Management

• Refactored post display logic to use the new Post class
• Maintained all existing functionality (view posts, add posts, admin access)
• Improved HTML escaping for XSS prevention

File Structure

phpblog/
├── src/
│   ├── Config.php      # Configuration management
│   ├── Database.php    # PDO database connection
│   ├── Post.php        # Post operations
│   └── Auth.php        # Authentication logic
├── admin/              # Admin interface (updated)
├── .env.example        # Environment template
├── .gitignore          # Git ignore rules
├── composer.json       # Dependency management
└── [documentation files]

Testing Performed

• ✅ Database connection with new PDO layer
• ✅ Post display on home page
• ✅ Admin login functionality
• ✅ Adding new posts through admin interface
• ✅ Session management and logout
• ✅ Configuration loading from .env file

Breaking Changes

⚠️ Action Required: Administrators must:

1. Install Composer dependencies (composer install)
2. Create .env file from .env.example
3. Update database credentials in .env
4. Run setup_db.sql to update admin password
5. Ensure PHP version >= 7.4

See MIGRATION.md for detailed upgrade instructions.

Backward Compatibility

• Maintains all existing user-facing functionality
• Database schema remains unchanged (except admin password hashing)
• All existing features work as before

Security Considerations

• All SQL queries now use prepared statements
• Password storage upgraded to bcrypt hashing
• Environment variables protect sensitive data
• Input sanitization applied to all user inputs
• Output escaping prevents XSS attacks

See SECURITY.md for complete security documentation.

Future Improvements

While this PR focuses on modernization, potential future enhancements could include:

• Unit tests with PHPUnit
• Frontend framework integration
• RESTful API endpoints
• Content pagination
• Rich text editor for posts
• Image upload support

References

• PHP PDO Documentation
• PHP Password Hashing
• OWASP PHP Security Cheat Sheet