Advanced WordPress Development

Chapter 1: Advanced WordPress Architecture

1.1 WordPress Core Structure

Understanding WordPress core architecture is essential for advanced development. WordPress follows a modular architecture that separates concerns between core functionality, themes, and plugins. This separation allows for flexibility and extensibility.

Core Components:

• WordPress Core: Core functionality and APIs that power WordPress
• Themes: Presentation layer that controls how content is displayed
• Plugins: Extend functionality without modifying core files
• Database: MySQL/MariaDB stores all content and settings
• File System: wp-content directory for themes, plugins, uploads

1.2 WordPress File Structure

Understanding the WordPress file structure helps in development and troubleshooting.

Key Directories:

• wp-admin: Admin dashboard files
• wp-includes: Core WordPress functions and classes
• wp-content: User-generated content (themes, plugins, uploads)
• wp-content/themes: Theme files
• wp-content/plugins: Plugin files
• wp-content/uploads: Media files

1.3 WordPress Loading Process

WordPress follows a specific loading sequence when processing requests.

// WordPress loading sequence
1. wp-config.php - Configuration loaded
2. wp-load.php - Core WordPress loaded
3. wp-settings.php - Settings and plugins initialized
4. Theme functions.php - Theme functions loaded
5. Template hierarchy - Appropriate template selected
6. Template rendered - Output sent to browser

1.4 WordPress Object-Oriented Architecture

Modern WordPress uses object-oriented programming patterns.

// Example: Using WordPress classes
class My_Custom_Class {
    public function __construct() {
        add_action('init', array($this, 'init'));
    }
    
    public function init() {
        // Initialization code
    }
}

new My_Custom_Class();

1.5 WordPress APIs and Functions

WordPress provides extensive APIs for development.

• Plugin API: Hooks and filters system
• Database API: WPDB class for database operations
• HTTP API: wp_remote_get/post for external requests
• File API: wp_upload_dir, wp_filesystem
• Options API: get_option, update_option