CodeIgniter 4 vs CodeIgniter 3

CodeIgniter is a popular PHP framework known for its simplicity and ease of use. The release of CodeIgniter 4 brought significant changes and improvements over CodeIgniter 3. Here’s a detailed comparison between the two versions:

CodeIgniter 4 vs CodeIgniter 3

Architecture and Design

• CodeIgniter 4:
• Namespaced Code: Uses PHP namespaces, which helps in avoiding class name conflicts and provides better autoloading.
• PSR Compliance: Follows PSR-4 for autoloading, PSR-1 for basic coding standards, and PSR-2 for coding style.
• Better Modular Separation: Provides a more modular structure, making it easier to manage large applications.
• Improved Dependency Management: Uses Composer for dependency management, allowing easier integration of third-party libraries.
• CodeIgniter 3:
• Non-Namespaced Code: Does not use PHP namespaces, which can lead to potential class name conflicts.
• CI Autoloading: Uses a custom autoloader instead of the PSR-4 standard.
• Legacy Code Structure: Less modular and harder to manage as the application grows.

Features and Functionality

• CodeIgniter 4:
• Improved Models: Introduces Entity classes and a more robust Query Builder with better support for complex queries.
• Routing: Enhanced routing system with more flexibility and support for HTTP verbs.
• CLI Tools: Comprehensive command-line tools for various tasks like migrations, seeding, and testing.
• Configuration: Simplified configuration files with environment-specific settings.
• Security: Built-in support for CSRF protection, improved validation, and escaping mechanisms.
• Testing: Integrated testing support with PHPUnit.
• CodeIgniter 3:
• Basic Models: Simpler model system without Entity classes, limiting advanced ORM capabilities.
• Basic Routing: Limited routing capabilities compared to CI4.
• CLI Tools: Basic command-line support, not as extensive as CI4.
• Configuration: Configuration files are not as streamlined and lack environment-specific settings.
• Security: Basic security features but not as comprehensive as CI4.
• Testing: No built-in support for testing, requiring third-party solutions.

Performance and Optimization

• CodeIgniter 4:
• PHP 7+ Compatibility: Designed to take full advantage of PHP 7+ features and optimizations.
• Caching: Improved caching mechanisms and support for multiple cache drivers.
• Database Handling: Better database performance with improved query builder and faster execution times.
• Memory Usage: More efficient memory usage due to modern PHP features and optimizations.
• CodeIgniter 3:
• PHP 5.6+ Compatibility: Compatible with PHP 5.6 and above, but does not fully utilize PHP 7+ enhancements.
• Caching: Basic caching support, less flexible than CI4.
• Database Handling: Adequate but not as optimized for performance as CI4.
• Memory Usage: Higher memory usage compared to CI4 due to older codebase and lack of modern optimizations.

Documentation and Community

• CodeIgniter 4:
• Updated Documentation: Comprehensive and updated documentation reflecting modern PHP practices.
• Active Development: Active community and regular updates with new features and bug fixes.
• Larger Community: Growing community with more contributors and plugins available.
• CodeIgniter 3:
• Legacy Documentation: Documentation is extensive but not as modernized as CI4.
• Stability Over Updates: More stable but receives fewer updates and new features.
• Established Community: Long-established community but may see a decline as users migrate to CI4.

Conclusion

CodeIgniter 4 represents a significant upgrade over CodeIgniter 3, with modern PHP practices, enhanced performance, better modularity, and a more robust feature set. For new projects, CodeIgniter 4 is the recommended choice due to its advanced capabilities and future-proof design. However, for legacy projects, CodeIgniter 3 may still be used if stability and minimal updates are preferred.