Reinstating render_callback

packages/block-library/src/image/index.php

@@ -6,34 +6,35 @@
  */
 
 /**
- * Adds a data-id attribute to the core Image block when nested in a Gallery block.
+ * Renders the `core/image` block on the server.
  *
- * @param  WP_Post $post The WP post.
- * @return string        Returns the post content with the data-id attribute added to gallery images.
+ * @param  array $attributes The block attributes.
+ * @param  array $content    The block content.
+ * @return string            Returns the block content with the data-id attribute added.
  */
-function get_block_core_image_post_content( $post ) {
-	if ( is_admin() ) {
-		return;
-	}
-	if ( has_blocks( $post->post_content ) ) {
-		$content = $post->post_content;
-		$blocks  = parse_blocks( $content );
-		foreach ( $blocks as $block ) {
-			if ( 'core/gallery' === $block['blockName'] && ! empty( $block['innerBlocks'] ) ) {
-				foreach ( $block['innerBlocks'] as $inner_block ) {
-					if ( 'core/image' === $inner_block['blockName'] ) {
-						if ( isset( $inner_block['attrs']['id'] ) ) {
-							$image_id          = esc_attr( $inner_block['attrs']['id'] );
-							$data_id_attribute = 'data-id="' . $image_id . '"';
-							$class_string      = 'class="wp-image-' . $image_id . '"';
-							$content           = str_replace( $class_string, $data_id_attribute . ' ' . $class_string, $content );
-						}
-					}
-				}
-			}
+function render_block_core_image( $attributes, $content ) {
+	if ( isset( $attributes['id'] ) ) {
+		// Add the data-id="$id" attribute to the img element
+		// to provide backwards compatibility for the Gallery Block,
+		// which now wraps Image Blocks within innerBlocks.
+		$data_id_attribute = 'data-id="' . esc_attr( $attributes['id'] ) . '"';
+		if ( ! strpos( $content, $data_id_attribute ) ) {
+			$content = str_replace( '<img', '<img ' . $data_id_attribute . ' ', $content );
 		}
 	}
-	$post->post_content = $content;
+	return $content;
 }
 
-add_action( 'the_post', 'get_block_core_image_post_content', 10, 1 );
+
+/**
+ * Register image block.
+ */
+function register_block_core_image() {
+	register_block_type_from_metadata(
+		__DIR__ . '/image',
+		array(
+			'render_callback' => 'render_block_core_image',
+		)
+	);
+}
+add_action( 'init', 'register_block_core_image' );