Mini Shell
<?php
/**
* Server-side rendering of the `core/legacy-widget` block.
*
* @package WordPress
*/
/**
* Renders the 'core/legacy-widget' block.
*
* @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.
*/
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.
*/
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 );