Shortcodes

Føhn provides #[AsShortcode] for registering shortcode handlers.

Basic Shortcode

<?php
// app/Hooks/Shortcodes.php

namespace App\Hooks;

use Studiometa\Foehn\Attributes\AsShortcode;

final class Shortcodes
{
    #[AsShortcode('button')]
    public function button(array $atts, ?string $content = null): string
    {
        $atts = shortcode_atts([
            'url' => '#',
            'target' => '_self',
            'class' => 'btn',
        ], $atts);

        return sprintf(
            '<a href="%s" target="%s" class="%s">%s</a>',
            esc_url($atts['url']),
            esc_attr($atts['target']),
            esc_attr($atts['class']),
            esc_html($content ?? 'Click here')
        );
    }
}

Usage:

[button url="https://example.com" class="btn btn-primary"]Learn More[/button]

Shortcode with Templates

For complex shortcodes, use templates:

<?php

namespace App\Hooks;

use Studiometa\Foehn\Attributes\AsShortcode;
use Studiometa\Foehn\Contracts\ViewEngineInterface;

final class Shortcodes
{
    public function __construct(
        private readonly ViewEngineInterface $view,
    ) {}

    #[AsShortcode('testimonial')]
    public function testimonial(array $atts): string
    {
        $atts = shortcode_atts([
            'id' => 0,
        ], $atts);

        $testimonial = \Timber\Timber::get_post($atts['id']);

        if (!$testimonial || $testimonial->post_type !== 'testimonial') {
            return '';
        }

        return $this->view->render('shortcodes/testimonial', [
            'testimonial' => $testimonial,
        ]);
    }
}

{# templates/shortcodes/testimonial.twig #}
<blockquote class="testimonial">
    <p class="testimonial__content">{{ testimonial.content }}</p>
    <footer class="testimonial__author">
        {% if testimonial.thumbnail %}
            <img src="{{ testimonial.thumbnail.src('thumbnail') }}" alt="{{ testimonial.meta('author_name') }}">
        {% endif %}
        <cite>{{ testimonial.meta('author_name') }}</cite>
    </footer>
</blockquote>

Multiple Shortcodes

<?php

namespace App\Hooks;

use Studiometa\Foehn\Attributes\AsShortcode;

final class Shortcodes
{
    #[AsShortcode('alert')]
    public function alert(array $atts, ?string $content = null): string
    {
        $atts = shortcode_atts([
            'type' => 'info',
        ], $atts);

        return sprintf(
            '<div class="alert alert--%s">%s</div>',
            esc_attr($atts['type']),
            wp_kses_post($content)
        );
    }

    #[AsShortcode('icon')]
    public function icon(array $atts): string
    {
        $atts = shortcode_atts([
            'name' => 'star',
            'size' => '24',
        ], $atts);

        return sprintf(
            '<svg class="icon icon--%s" width="%s" height="%s">
                <use href="#icon-%s"></use>
            </svg>',
            esc_attr($atts['name']),
            esc_attr($atts['size']),
            esc_attr($atts['size']),
            esc_attr($atts['name'])
        );
    }

    #[AsShortcode('year')]
    public function year(): string
    {
        return date('Y');
    }
}

Dynamic Content Shortcodes

#[AsShortcode('recent_posts')]
public function recentPosts(array $atts): string
{
    $atts = shortcode_atts([
        'count' => 5,
        'category' => '',
    ], $atts);

    $args = [
        'post_type' => 'post',
        'posts_per_page' => (int) $atts['count'],
    ];

    if ($atts['category']) {
        $args['category_name'] = $atts['category'];
    }

    $posts = \Timber\Timber::get_posts($args);

    return $this->view->render('shortcodes/recent-posts', [
        'posts' => $posts,
    ]);
}

Usage:

[recent_posts count="3" category="news"]

Contact Form Shortcode

#[AsShortcode('contact_form')]
public function contactForm(array $atts): string
{
    $atts = shortcode_atts([
        'recipient' => get_option('admin_email'),
        'subject' => 'Contact Form Submission',
    ], $atts);

    return $this->view->render('shortcodes/contact-form', [
        'form_id' => 'contact-' . wp_unique_id(),
        'recipient' => $atts['recipient'],
        'subject' => $atts['subject'],
    ]);
}

Enclosing Shortcodes

Handle content between opening and closing tags:

#[AsShortcode('spoiler')]
public function spoiler(array $atts, ?string $content = null): string
{
    $atts = shortcode_atts([
        'title' => 'Spoiler',
    ], $atts);

    return sprintf(
        '<details class="spoiler">
            <summary>%s</summary>
            <div class="spoiler__content">%s</div>
        </details>',
        esc_html($atts['title']),
        do_shortcode($content ?? '')
    );
}

Usage:

[spoiler title="Click to reveal"]
This content is hidden by default.
[/spoiler]

Nested Shortcodes

Support nested shortcode processing:

#[AsShortcode('tabs')]
public function tabs(array $atts, ?string $content = null): string
{
    // Process nested [tab] shortcodes
    $content = do_shortcode($content ?? '');

    return sprintf(
        '<div class="tabs">%s</div>',
        $content
    );
}

#[AsShortcode('tab')]
public function tab(array $atts, ?string $content = null): string
{
    $atts = shortcode_atts([
        'title' => 'Tab',
    ], $atts);

    return sprintf(
        '<div class="tab" data-title="%s">%s</div>',
        esc_attr($atts['title']),
        wp_kses_post($content)
    );
}

Usage:

[tabs]
[tab title="First"]Content for first tab[/tab]
[tab title="Second"]Content for second tab[/tab]
[/tabs]

Organizing Shortcodes

app/Hooks/
├── Shortcodes/
│   ├── ButtonShortcode.php
│   ├── AlertShortcode.php
│   ├── FormShortcodes.php
│   └── ContentShortcodes.php

Or group related shortcodes:

// app/Hooks/UIShortcodes.php
final class UIShortcodes
{
    #[AsShortcode('button')]
    public function button() {}

    #[AsShortcode('alert')]
    public function alert() {}

    #[AsShortcode('card')]
    public function card() {}
}

// app/Hooks/ContentShortcodes.php
final class ContentShortcodes
{
    #[AsShortcode('recent_posts')]
    public function recentPosts() {}

    #[AsShortcode('testimonial')]
    public function testimonial() {}
}

Security Best Practices

Shortcode output is rendered directly in page content, making proper escaping critical to prevent XSS vulnerabilities.

Always Escape Output

Every dynamic value in your shortcode output must be escaped using the appropriate function:

#[AsShortcode('profile')]
public function profile(array $atts, ?string $content = null): string
{
    $atts = shortcode_atts([
        'name' => '',
        'url' => '#',
        'class' => 'profile',
    ], $atts);

    return sprintf(
        '<div class="%s">
            <a href="%s">%s</a>
            <p>%s</p>
        </div>',
        esc_attr($atts['class']),      // HTML attribute
        esc_url($atts['url']),         // URL
        esc_html($atts['name']),       // Plain text
        wp_kses_post($content)         // Rich HTML content
    );
}

Escaping Function Reference

Function	Use For	Example Context
esc_html()	Plain text	Text inside tags
esc_attr()	Attribute values	class="", data-*=""
esc_url()	URLs	href="", src=""
wp_kses_post()	HTML allowing safe tags	User-provided rich content
wp_kses()	HTML with custom whitelist	Restricted formatting

Common Mistakes

// ❌ DANGEROUS: Unescaped attributes allow XSS
#[AsShortcode('link')]
public function unsafeLink(array $atts): string
{
    return '<a href="' . $atts['url'] . '" class="' . $atts['class'] . '">Click</a>';
}

// ✅ SAFE: All output properly escaped
#[AsShortcode('link')]
public function safeLink(array $atts): string
{
    $atts = shortcode_atts([
        'url' => '#',
        'class' => 'link',
        'text' => 'Click here',
    ], $atts);

    return sprintf(
        '<a href="%s" class="%s">%s</a>',
        esc_url($atts['url']),
        esc_attr($atts['class']),
        esc_html($atts['text'])
    );
}

Template-Based Shortcodes

When using Twig templates, rely on Twig's auto-escaping but be careful with |raw:

{# templates/shortcodes/card.twig #}
<div class="{{ class }}"> {# Auto-escaped #}
    <h3>{{ title }}</h3>   {# Auto-escaped #}
    <a href="{{ url|e('url') }}">{{ link_text }}</a>
    <div class="content">{{ content|raw }}</div> {# Only for trusted HTML #}
</div>

For detailed security guidance, see the Security Guide.

See Also

• API Reference: #[AsShortcode]
• Security Guide