<?php 
/** 
 * Server-side rendering of the `core/legacy-widget` block. 
 * 
 * @package WordPress 
 */ 
 
/** 
 * Renders the 'core/legacy-widget' block. 
 * 
 * @since 5.8.0 
 * 
 * @global int $wp_widget_factory. 
 * 
 * @param array $attributes The block attributes. 
 * 
 * @return string Rendered block. 
 */ 
function render_block_core_legacy_widget( $attributes ) { 
    global $wp_widget_factory; 
 
    if ( isset( $attributes['id'] ) ) { 
        $sidebar_id = wp_find_widgets_sidebar( $attributes['id'] ); 
        return wp_render_widget( $attributes['id'], $sidebar_id ); 
    } 
 
    if ( ! isset( $attributes['idBase'] ) ) { 
        return ''; 
    } 
 
    $id_base       = $attributes['idBase']; 
    $widget_key    = $wp_widget_factory->get_widget_key( $id_base ); 
    $widget_object = $wp_widget_factory->get_widget_object( $id_base ); 
 
    if ( ! $widget_key || ! $widget_object ) { 
        return ''; 
    } 
 
    if ( isset( $attributes['instance']['encoded'], $attributes['instance']['hash'] ) ) { 
        $serialized_instance = base64_decode( $attributes['instance']['encoded'] ); 
        if ( ! hash_equals( wp_hash( $serialized_instance ), (string) $attributes['instance']['hash'] ) ) { 
            return ''; 
        } 
        $instance = unserialize( $serialized_instance ); 
    } else { 
        $instance = array(); 
    } 
 
    $args = array( 
        'widget_id'   => $widget_object->id, 
        'widget_name' => $widget_object->name, 
    ); 
 
    ob_start(); 
    the_widget( $widget_key, $instance, $args ); 
    return ob_get_clean(); 
} 
 
/** 
 * Registers the 'core/legacy-widget' block. 
 * 
 * @since 5.8.0 
 */ 
function register_block_core_legacy_widget() { 
    register_block_type_from_metadata( 
        __DIR__ . '/legacy-widget', 
        array( 
            'render_callback' => 'render_block_core_legacy_widget', 
        ) 
    ); 
} 
 
add_action( 'init', 'register_block_core_legacy_widget' ); 
 
/** 
 * Intercepts any request with legacy-widget-preview in the query param and, if 
 * set, renders a page containing a preview of the requested Legacy Widget 
 * block. 
 * 
 * @since 5.8.0 
 */ 
function handle_legacy_widget_preview_iframe() { 
    if ( empty( $_GET['legacy-widget-preview'] ) ) { 
        return; 
    } 
 
    if ( ! current_user_can( 'edit_theme_options' ) ) { 
        return; 
    } 
 
    define( 'IFRAME_REQUEST', true ); 
 
    ?> 
    <!doctype html> 
    <html <?php language_attributes(); ?>> 
    <head> 
        <meta charset="<?php bloginfo( 'charset' ); ?>" /> 
        <meta name="viewport" content="width=device-width, initial-scale=1" /> 
        <link rel="profile" href="https://gmpg.org/xfn/11" /> 
        <?php wp_head(); ?> 
        <style> 
            /* Reset theme styles */ 
            html, body, #page, #content { 
                padding: 0 !important; 
                margin: 0 !important; 
            } 
 
            /* Hide root level text nodes */ 
            body { 
                font-size: 0 !important; 
            } 
 
            /* Hide non-widget elements */ 
            body *:not(#page):not(#content):not(.widget):not(.widget *) { 
                display: none !important; 
                font-size: 0 !important; 
                height: 0 !important; 
                left: -9999px !important; 
                max-height: 0 !important; 
                max-width: 0 !important; 
                opacity: 0 !important; 
                pointer-events: none !important; 
                position: absolute !important; 
                top: -9999px !important; 
                transform: translate(-9999px, -9999px) !important; 
                visibility: hidden !important; 
                z-index: -999 !important; 
            } 
 
            /* Restore widget font-size */ 
            .widget { 
                font-size: var(--global--font-size-base); 
            } 
        </style> 
    </head> 
    <body <?php body_class(); ?>> 
        <div id="page" class="site"> 
            <div id="content" class="site-content"> 
                <?php 
                $registry = WP_Block_Type_Registry::get_instance(); 
                $block    = $registry->get_registered( 'core/legacy-widget' ); 
                echo $block->render( $_GET['legacy-widget-preview'] ); 
                ?> 
            </div><!-- #content --> 
        </div><!-- #page --> 
        <?php wp_footer(); ?> 
    </body> 
    </html> 
    <?php 
 
    exit; 
} 
 
// Use admin_init instead of init to ensure get_current_screen function is already available. 
// This isn't strictly required, but enables better compatibility with existing plugins. 
// See: https://github.com/WordPress/gutenberg/issues/32624. 
add_action( 'admin_init', 'handle_legacy_widget_preview_iframe', 20 ); 
 
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