GetListenerFilters() helper and Injector interface for implementations.

interface.go

@@ -13,3 +13,7 @@ type Relay interface {
 	SaveEvent(*event.Event) error
 	QueryEvents(*filter.EventFilter) ([]event.Event, error)
 }
+
+type Injector interface {
+	InjectEvents() chan event.Event
+}

listener.go

@@ -15,6 +15,39 @@ type Listener struct {
 var listeners = make(map[*websocket.Conn]map[string]*Listener)
 var listenersMutex = sync.Mutex{}
 
+func GetListeningFilters() filter.EventFilters {
+	var respfilters = make(filter.EventFilters, 0, len(listeners)*2)
+
+	listenersMutex.Lock()
+	defer func() {
+		listenersMutex.Unlock()
+	}()
+
+	// here we go through all the existing listeners
+	for _, connlisteners := range listeners {
+		for _, listener := range connlisteners {
+			for _, listenerfilter := range listener.filters {
+				for _, respfilter := range respfilters {
+					// check if this filter specifically is already added to respfilters
+					if filter.Equal(listenerfilter, respfilter) {
+						goto nextconn
+					}
+				}
+
+				// field not yet present on respfilters, add it
+				respfilters = append(respfilters, listenerfilter)
+
+				// continue to the next filter
+			nextconn:
+				continue
+			}
+		}
+	}
+
+	// respfilters will be a slice with all the distinct filter we currently have active
+	return respfilters
+}
+
 func setListener(id string, conn *websocket.Conn, filters filter.EventFilters) {
 	listenersMutex.Lock()
 	defer func() {

start.go

@@ -27,9 +27,16 @@ func Start(relay Relay) {
 		Log.Fatal().Err(err).Msg("failed to start")
 	}
 
-	// NIP01
 	router.Path("/").Methods("GET").HandlerFunc(handleWebsocket(relay))
 
+	if inj, ok := relay.(Injector); ok {
+		go func() {
+			for event := range inj.InjectEvents() {
+				notifyListeners(&event)
+			}
+		}()
+	}
+
 	srv := &http.Server{
 		Handler:           cors.Default().Handler(router),
 		Addr:              s.Host + ":" + s.Port,