writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
			return
		}

		suffix = values[peerRESTListenSuffix][0]
	}

	pattern := event.NewPattern(prefix, suffix)

	var eventNames []event.Name
	var mask pubsub.Mask
	for _, s := range values[peerRESTListenEvents] {
		eventName, err := event.ParseName(s)
		if err != nil {

		if err := event.ValidateFilterRuleValue(values[peerRESTListenSuffix][0]); err != nil {
			return grid.NewRemoteErr(err)
		}

		suffix = values[peerRESTListenSuffix][0]
	}

	pattern := event.NewPattern(prefix, suffix)

	var eventNames []event.Name
	var mask pubsub.Mask
	for _, ev := range values[peerRESTListenEvents] {
		eventName, err := event.ParseName(ev)
		if err != nil {