wp_ajax_query_attachments()

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 WP-3.7.0
	 *
	 * @see WP_Query::parse_query()
	 *
	 * @param array $query An array of query variables.
	 */
	$query = apply_filters( 'ajax_query_attachments_args', $query );
	$query = new WP_Query( $query );

	$posts = array_map( 'wp_prepare_attachment_for_js', $query->posts );
	$posts = array_filter( $posts );

	wp_send_json_success( $posts );
}