Update Image Alt Text in All Blocks (Multisite + Custom Blocks)

gistfile1.txt

<?php
/**
 * Plugin Name: Update Image Alt Text in All Blocks (Multisite + Custom Blocks)
 * Description: WP-CLI command to update alt text in all images inside blocks for all sites in a multisite network, including custom blocks.
 */

if ( defined( 'WP_CLI' ) && WP_CLI ) {

	class Network_Update_All_Image_Alts_Command {

		/**
		 * Run the image alt text update across all sites in the network.
		 *
		 * ## EXAMPLES
		 *
		 *     wp network-update-all-image-alts
		 *
		 * @when after_wp_load
		 */
		public function __invoke() {

			if ( ! is_multisite() ) {
				WP_CLI::error( 'This command is for multisite installs only.' );
				return;
			}

			$sites = get_sites( array( 'number' => 0 ) );

			WP_CLI::log( 'Starting alt text updates on ' . count( $sites ) . ' sites...' );

			foreach ( $sites as $site ) {
				switch_to_blog( $site->blog_id );

				$site_name = get_bloginfo( 'name' );
				WP_CLI::log( "Processing site: {$site_name} (ID: {$site->blog_id})" );

				$updated_count = $this->run_image_alt_update_on_current_site();

				WP_CLI::log( "Finished {$site_name}: {$updated_count} posts/pages updated.\n" );

				restore_current_blog();
			}

			WP_CLI::success( 'All sites processed!' );
		}

		/**
		 * Runs the image alt text update on the current site.
		 *
		 * @return int Number of updated posts.
		 */
		private function run_image_alt_update_on_current_site() {

			$args = array(
				'post_type'      => array( 'post', 'page' ), // Add CPTs if needed.
				'post_status'    => 'publish',
				'posts_per_page' => -1,
			);

			$query         = new WP_Query( $args );
			$updated_count = 0;

			foreach ( $query->posts as $post ) {
				$original_content = $post->post_content;
				$updated_content  = $this->update_image_alts_in_all_blocks( $original_content );

				if ( $updated_content !== $original_content ) {
					wp_update_post(
						array(
							'ID'           => $post->ID,
							'post_content' => $updated_content,
						)
					);

					WP_CLI::log( "Updated post ID {$post->ID} ({$post->post_title})" );
					++$updated_count;
				}
			}

			return $updated_count;
		}

		/**
		 * Parses and updates alt text for images in all blocks within post content.
		 * Uses serialize_blocks() to preserve block markup.
		 *
		 * @param string $content The post content.
		 * @return string Updated content.
		 */
		private function update_image_alts_in_all_blocks( $content ) {

			$blocks         = parse_blocks( $content );
			$updated_blocks = array();

			foreach ( $blocks as $block ) {
				$updated_blocks[] = $this->process_any_block_recursive( $block );
			}

			// Use serialize_blocks() to keep block markup intact.
			return serialize_blocks( $updated_blocks );
		}

		/**
		 * Recursively process blocks to update image alt text.
		 *
		 * @param array $block
		 * @return array
		 */
		private function process_any_block_recursive( $block ) {

			// === Generic Core Block Handling ===
			if ( ! empty( $block['attrs'] ) && ! empty( $block['attrs']['id'] ) ) {
				$attachment_id = $block['attrs']['id'];
				$media_alt     = get_post_meta( $attachment_id, '_wp_attachment_image_alt', true );

				if ( $media_alt ) {
					if ( empty( $block['attrs']['alt'] ) || $block['attrs']['alt'] !== $media_alt ) {
						$block['attrs']['alt'] = $media_alt;
					}
				}
			}

			if ( ! empty( $block['attrs']['images'] ) && is_array( $block['attrs']['images'] ) ) {
				foreach ( $block['attrs']['images'] as &$image ) {
					if ( ! empty( $image['id'] ) ) {
						$attachment_id = $image['id'];
						$media_alt     = get_post_meta( $attachment_id, '_wp_attachment_image_alt', true );

						if ( $media_alt ) {
							if ( empty( $image['alt'] ) || $image['alt'] !== $media_alt ) {
								$image['alt'] = $media_alt;
							}
						}
					}
				}
			}

			// === Custom Kirkwood Block Handling ===
			if ( $block['blockName'] === 'kirkwood/story-section-block' && ! empty( $block['attrs']['sections'] ) ) {

				foreach ( $block['attrs']['sections'] as $section_key => &$section_data ) {

					// Main imageID handling
					if ( isset( $section_data['imageID'] ) && is_numeric( $section_data['imageID'] ) ) {
						$attachment_id = $section_data['imageID'];
						$media_alt     = get_post_meta( $attachment_id, '_wp_attachment_image_alt', true );

						if ( $media_alt ) {
							if ( empty( $section_data['altText'] ) || $section_data['altText'] !== $media_alt ) {
								$section_data['altText'] = $media_alt;
							}
						}
					}

					// Optional: Mobile ImageID handling
					if ( isset( $section_data['mobileImageID'] ) && is_numeric( $section_data['mobileImageID'] ) ) {
						$attachment_id = $section_data['mobileImageID'];
						$media_alt     = get_post_meta( $attachment_id, '_wp_attachment_image_alt', true );

						if ( $media_alt ) {
							if ( empty( $section_data['mobileAltText'] ) || $section_data['mobileAltText'] !== $media_alt ) {
								$section_data['mobileAltText'] = $media_alt;
							}
						}
					}
				}
			}

			// === Recursively Process Inner Blocks ===
			if ( ! empty( $block['innerBlocks'] ) ) {
				foreach ( $block['innerBlocks'] as &$inner_block ) {
					$inner_block = $this->process_any_block_recursive( $inner_block );
				}
			}

			return $block;
		}
	}

	// Register the WP-CLI command.
	WP_CLI::add_command( 'network-update-all-image-alts', 'Network_Update_All_Image_Alts_Command' );
}