Role-Scoped Listener Pattern • Description: Extends WordPress hooks by allowing specific actions or filters to execute only for users with defined roles or capabilities. Ideal for ensuring role-based access to functionality or modifying content dynamically based on user permissions.

role-scope-listener.php

<?php
/**
 * Role-Scoped Listener Class
 *
 * Allows specific WordPress hooks to be executed only for users with designated roles.
 */
class Role_Scoped_Listener {
    /**
     * The name of the WordPress hook.
     *
     * @var string
     */
    private $hook_name;

    /**
     * The callback function to execute.
     *
     * @var callable
     */
    private $callback;

    /**
     * An array of allowed roles.
     *
     * @var array
     */
    private $roles;

    /**
     * Constructor.
     *
     * @param string   $hook_name The WordPress hook name.
     * @param callable $callback  The callback to execute.
     * @param array    $roles     The roles allowed to trigger the callback.
     */
    public function __construct( $hook_name, $callback, $roles ) {
        $this->hook_name = $hook_name;
        $this->callback  = $callback;
        $this->roles     = $roles;

        // Attach the listener to the specified hook.
        add_action( $this->hook_name, [ $this, 'execute' ], 10, 2 );
    }

    /**
     * Executes the callback if the user has the appropriate role.
     *
     * @param mixed ...$args Arguments passed by the hook.
     */
    public function execute( ...$args ) {
        if ( $this->user_has_role() ) {
            call_user_func_array( $this->callback, $args );
        }
    }

    /**
     * Checks if the current user has any of the specified roles.
     *
     * @return bool True if the user has one of the roles, false otherwise.
     */
    private function user_has_role() {
        if ( ! is_user_logged_in() ) {
            return false;
        }

        $user = wp_get_current_user();

        foreach ( $this->roles as $role ) {
            if ( in_array( $role, (array) $user->roles, true ) ) {
                return true;
            }
        }

        return false;
    }
}

// Example Use Case: Display Custom Admin Notices for Specific Roles.
new Role_Scoped_Listener(
    'admin_notices',
    function() {
        echo '<div class="notice notice-success"><p>' . esc_html__( 'Welcome, Admin! Here’s your custom notice.', 'text-domain' ) . '</p></div>';
    },
    [ 'administrator' ]
);

new Role_Scoped_Listener(
    'admin_notices',
    function() {
        echo '<div class="notice notice-info"><p>' . esc_html__( 'Hello, Editor! You have special access to this feature.', 'text-domain' ) . '</p></div>';
    },
    [ 'editor' ]
);

// Example Use Case: Add Custom Styles for Specific Roles.
new Role_Scoped_Listener(
    'wp_enqueue_scripts',
    function() {
        wp_enqueue_style( 'editor-style', get_template_directory_uri() . '/css/editor-style.css', [], '1.0.0' );
    },
    [ 'editor' ]
);

new Role_Scoped_Listener(
    'wp_enqueue_scripts',
    function() {
        wp_enqueue_style( 'subscriber-style', get_template_directory_uri() . '/css/subscriber-style.css', [], '1.0.0' );
    },
    [ 'subscriber' ]
);