WordPress Plugin Development Fundamentals

Creating custom WordPress plugins requires understanding WordPress architecture, security best practices, and proper coding standards.

Plugin Structure

A well-organized plugin should follow this structure:

my-plugin/
  my-plugin.php
  includes/
     class-main.php
     class-admin.php
  assets/
     css/
     js/
  languages/
  readme.txt

Security Best Practices

• Sanitize Input: Always sanitize user input using WordPress functions
• Validate Data: Validate all data before processing
• Escape Output: Escape data when outputting to prevent XSS
• Use Nonces: Implement nonces for form submissions

WordPress Hooks

Proper use of actions and filters is crucial for plugin development:

// Action Hook
add_action('init', 'my_plugin_init');

// Filter Hook  
add_filter('the_content', 'my_plugin_modify_content');

Database Operations

Always use WordPress database API for secure database operations:

global $wpdb;
$results = $wpdb->get_results(
  $wpdb->prepare("SELECT * FROM {$wpdb->posts} WHERE ID = %d", $id)
);

Plugin Activation and Deactivation

Handle plugin lifecycle events properly:

register_activation_hook(__FILE__, 'my_plugin_activate');
register_deactivation_hook(__FILE__, 'my_plugin_deactivate');