Hooks

Foehn provides #[AsAction] and #[AsFilter] attributes to register WordPress hooks declaratively.

Actions

Use #[AsAction] to register action hooks:

<?php

namespace App\Hooks;

use Studiometa\Foehn\Attributes\AsAction;

final class ThemeHooks
{
    #[AsAction('after_setup_theme')]
    public function setupTheme(): void
    {
        add_theme_support('post-thumbnails');
        add_theme_support('title-tag');
        add_theme_support('html5', ['search-form', 'gallery', 'caption']);
    }

    #[AsAction('wp_enqueue_scripts')]
    public function enqueueAssets(): void
    {
        wp_enqueue_style('theme-style', get_stylesheet_uri());
        wp_enqueue_script('theme-script', get_template_directory_uri() . '/dist/main.js');
    }
}

Priority and Arguments

You can specify priority and the number of accepted arguments:

#[AsAction('save_post', priority: 20, acceptedArgs: 3)]
public function onSavePost(int $postId, WP_Post $post, bool $update): void
{
    if ($post->post_type !== 'product') {
        return;
    }

    // Handle product save
}

Multiple Actions

A method can respond to multiple actions:

#[AsAction('admin_init')]
#[AsAction('init')]
public function initialize(): void
{
    // Runs on both hooks
}

Filters

Use #[AsFilter] to register filter hooks:

<?php

namespace App\Hooks;

use Studiometa\Foehn\Attributes\AsFilter;

final class ContentFilters
{
    #[AsFilter('the_content')]
    public function filterContent(string $content): string
    {
        // Add wrapper div around content
        return '<div class="content-wrapper">' . $content . '</div>';
    }

    #[AsFilter('excerpt_length')]
    public function excerptLength(): int
    {
        return 30;
    }

    #[AsFilter('excerpt_more')]
    public function excerptMore(): string
    {
        return '...';
    }
}

Filter with Multiple Arguments

#[AsFilter('wp_nav_menu_items', priority: 10, acceptedArgs: 2)]
public function addSearchToMenu(string $items, object $args): string
{
    if ($args->theme_location === 'primary') {
        $items .= '<li>' . get_search_form(false) . '</li>';
    }

    return $items;
}

Dependency Injection

Hook handlers support constructor dependency injection:

<?php

namespace App\Hooks;

use App\Services\AnalyticsService;
use Studiometa\Foehn\Attributes\AsAction;

final class AnalyticsHooks
{
    public function __construct(
        private readonly AnalyticsService $analytics,
    ) {}

    #[AsAction('wp_footer')]
    public function trackPageView(): void
    {
        $this->analytics->trackPageView(get_the_ID());
    }
}

Organizing Hooks

Group related hooks in dedicated classes:

app/Hooks/
├── ThemeHooks.php      # Theme setup, supports
├── AssetHooks.php      # Scripts, styles
├── ContentHooks.php    # Content filters
├── AdminHooks.php      # Admin-only hooks
└── SeoHooks.php        # SEO-related hooks

Common Hooks Reference

Theme Setup

#[AsAction('after_setup_theme')]
public function setup(): void
{
    // Theme supports
    add_theme_support('post-thumbnails');
    add_theme_support('title-tag');
    add_theme_support('custom-logo');
    add_theme_support('editor-styles');

    // Register menus
    register_nav_menus([
        'primary' => 'Primary Menu',
        'footer' => 'Footer Menu',
    ]);

    // Add image sizes
    add_image_size('hero', 1920, 800, true);
}

Admin Customizations

#[AsAction('admin_menu')]
public function customizeAdminMenu(): void
{
    remove_menu_page('edit-comments.php');
}

#[AsAction('admin_bar_menu', priority: 999)]
public function customizeAdminBar(\WP_Admin_Bar $adminBar): void
{
    $adminBar->remove_node('comments');
}

Login Customizations

#[AsFilter('login_headerurl')]
public function loginLogoUrl(): string
{
    return home_url();
}

#[AsAction('login_enqueue_scripts')]
public function loginStyles(): void
{
    wp_enqueue_style('login-style', get_template_directory_uri() . '/dist/login.css');
}

Built-in Hooks

Foehn provides a collection of opt-in reusable hook classes for common WordPress patterns. These are not enabled by default — you choose which ones to activate via the hooks configuration option.

Enabling Built-in Hooks

use Studiometa\Foehn\Kernel;
use Studiometa\Foehn\Hooks\Cleanup\DisableEmoji;
use Studiometa\Foehn\Hooks\Cleanup\CleanHeadTags;
use Studiometa\Foehn\Hooks\Security\SecurityHeaders;
use Studiometa\Foehn\Hooks\YouTubeNoCookieHooks;

Kernel::boot(__DIR__ . '/app', [
    'hooks' => [
        // Cleanup
        DisableEmoji::class,
        CleanHeadTags::class,

        // Security
        SecurityHeaders::class,

        // GDPR
        YouTubeNoCookieHooks::class,
    ],
]);

Cleanup Hooks

Located in Studiometa\Foehn\Hooks\Cleanup:

Class	Description
CleanContent	Remove empty <p> tags and archive title prefixes
CleanHeadTags	Remove wlwmanifest, RSD, shortlink, REST discovery links
CleanImageSizes	Remove default WordPress image sizes (medium_large, 1536x1536, 2048x2048)
DisableEmoji	Remove emoji scripts, styles, and TinyMCE plugin
DisableFeeds	Disable RSS/Atom feeds
DisableGlobalStyles	Remove global styles and SVG filters from wp_head
DisableOembed	Disable oEmbed discovery and related scripts

Security Hooks

Located in Studiometa\Foehn\Hooks\Security:

Class	Description
DisableFileEditor	Disable theme/plugin editor in admin
DisableVersionDisclosure	Remove WordPress version from head, feeds, and scripts
DisableXmlRpc	Disable XML-RPC completely
RestApiAuth	Require authentication for REST API requests
SecurityHeaders	Send security headers (X-Content-Type-Options, X-Frame-Options, etc.)

GDPR Hooks

Located in Studiometa\Foehn\Hooks:

Class	Description
YouTubeNoCookieHooks	Replace YouTube embeds with youtube-nocookie.com

Example: Production Configuration

use Studiometa\Foehn\Kernel;
use Studiometa\Foehn\Hooks\Cleanup\{
    CleanContent,
    CleanHeadTags,
    CleanImageSizes,
    DisableEmoji,
    DisableGlobalStyles,
};
use Studiometa\Foehn\Hooks\Security\{
    DisableFileEditor,
    DisableVersionDisclosure,
    DisableXmlRpc,
    SecurityHeaders,
};
use Studiometa\Foehn\Hooks\YouTubeNoCookieHooks;

Kernel::boot(__DIR__ . '/app', [
    'discovery_cache' => 'full',
    'hooks' => [
        // Cleanup for leaner output
        CleanContent::class,
        CleanHeadTags::class,
        CleanImageSizes::class,
        DisableEmoji::class,
        DisableGlobalStyles::class,

        // Security hardening
        DisableFileEditor::class,
        DisableVersionDisclosure::class,
        DisableXmlRpc::class,
        SecurityHeaders::class,

        // GDPR compliance
        YouTubeNoCookieHooks::class,
    ],
]);

See Also

• API Reference: #[AsAction]
• API Reference: #[AsFilter]
• API Reference: Kernel