wp_ajax_query_attachments() WordPress Function

function wp_ajax_query_attachments() {
	if ( ! current_user_can( 'upload_files' ) ) {
		wp_send_json_error();
	}

	$query = isset( $_REQUEST['query'] ) ? (array) $_REQUEST['query'] : array();
	$keys  = array(
		's',
		'order',
		'orderby',
		'posts_per_page',
		'paged',
		'post_mime_type',
		'post_parent',
		'author',
		'post__in',
		'post__not_in',
		'year',
		'monthnum',
	);

	foreach ( get_taxonomies_for_attachments( 'objects' ) as $t ) {
		if ( $t->query_var && isset( $query[ $t->query_var ] ) ) {
			$keys[] = $t->query_var;
		}
	}

	$query              = array_intersect_key( $query, array_flip( $keys ) );
	$query['post_type'] = 'attachment';

	if (
		MEDIA_TRASH &&
		! empty( $_REQUEST['query']['post_status'] ) &&
		'trash' === $_REQUEST['query']['post_status']
	) {
		$query['post_status'] = 'trash';
	} else {
		$query['post_status'] = 'inherit';
	}

	if ( current_user_can( get_post_type_object( 'attachment' )->cap->read_private_posts ) ) {
		$query['post_status'] .= ',private';
	}

	// Filter query clauses to include filenames.
	if ( isset( $query['s'] ) ) {
		add_filter( 'posts_clauses', '_filter_query_attachment_filenames' );
	}

	/**
	 * Filters the arguments passed to WP_Query during an Ajax
	 * call for querying attachments.
	 *
	 * @since 3.7.0
	 *
	 * @see WP_Query::parse_query()
	 *
	 * @param array $query An array of query variables.
	 */
	$query             = apply_filters( 'ajax_query_attachments_args', $query );
	$attachments_query = new WP_Query( $query );

	$posts       = array_map( 'wp_prepare_attachment_for_js', $attachments_query->posts );
	$posts       = array_filter( $posts );
	$total_posts = $attachments_query->found_posts;

	if ( $total_posts < 1 ) {
		// Out-of-bounds, run the query again without LIMIT for total count.
		unset( $query['paged'] );

		$count_query = new WP_Query();
		$count_query->query( $query );
		$total_posts = $count_query->found_posts;
	}

	$posts_per_page = (int) $attachments_query->get( 'posts_per_page' );

	$max_pages = $posts_per_page ? ceil( $total_posts / $posts_per_page ) : 0;

	header( 'X-WP-Total: ' . (int) $total_posts );
	header( 'X-WP-TotalPages: ' . (int) $max_pages );

	wp_send_json_success( $posts );
}