[ElasticPress] Sync and search for Media (attachment) posts in WordPress

elasticpress-sync-attachments.php

<?php
/**
 * Sync and search for Media (attachment) posts in WordPress.
 * It is NOT to be used with the ElasticPress's Documents feature
 */

/**
 * Add the attachment post type to be indexable and searchable
 *
 * @param array $post_types Post types
 * @return array
 */
function ep_3189_add_attachment( $post_types ) {
	$post_types['attachment'] = 'attachment';
	return $post_types;
}
add_filter( 'ep_indexable_post_types', 'ep_3189_add_attachment' );
add_filter( 'ep_searchable_post_types', 'ep_3189_add_attachment' );

/**
 * Add the `inherit` post status to a search query, so it can also find attachments
 *
 * @param WP_Query $query The WP Query object
 */
function ep_3189_add_inherit_to_search_query( $query ) {
	$s = $query->get( 's', false );

	if ( empty( $s ) ) {
		return;
	}

	$post_type   = $query->get( 'post_type', [] );
	if ( ! empty( $post_type ) ) {
		if ( 'any' !== $post_type ) {
			if ( is_string( $post_type ) ) {
				$post_type   = explode( ' ', $post_type );
				$post_type[] = 'attachment';

				$query->set( 'post_type', array_unique( $post_type ) );
			}
		}
	}

	if ( empty( $post_status ) ) {
		$post_status = array_values(
			get_post_stati(
				[
					'public'              => true,
					'exclude_from_search' => false,
				]
			)
		);

		// Add inherit for documents
		$post_status[] = 'inherit';
	} else {
		if ( is_string( $post_status ) ) {
			$post_status = explode( ' ', $post_status );
		}

		$post_status[] = 'inherit';
	}

	$query->set( 'post_status', array_unique( $post_status ) );
}
add_action( 'pre_get_posts', 'ep_3189_add_inherit_to_search_query' );

/**
 * Add the `inherit` post status to be indexed
 *
 * @param array $statuses Indexable post stati
 * @return array
 */
function ep_3189_indexable_post_status( $statuses ) {
	if ( ! array_search( 'inherit', $statuses, true ) ) {
		$statuses[] = 'inherit';
	}

	return $statuses;
}
add_filter( 'ep_indexable_post_status', 'ep_3189_indexable_post_status' );