Turn adsb-ws into a json repeater, rather than a protocol converter

sinks/adsb-ws/hub.go

@@ -0,0 +1,41 @@
+package main
+
+type hub struct {
+	connections map[*connection]bool
+	broadcast chan []byte
+	register chan *connection
+	unregister chan *connection
+}
+
+var h = hub{
+	broadcast:   make(chan []byte),
+	register:    make(chan *connection),
+	unregister:  make(chan *connection),
+	connections: make(map[*connection]bool),
+}
+
+func (h *hub) run() {
+	for {
+		select {
+		case c := <-h.register:
+			h.connections[c] = true
+
+		case c := <-h.unregister:
+			_, ok := h.connections[c]
+			if ok {
+				delete(h.connections, c)
+				close(c.send)
+			}
+
+		case m := <-h.broadcast:
+			for c := range h.connections {
+				select {
+				case c.send <- m:
+				default:
+					close(c.send)
+					delete(h.connections, c)
+				}
+			}
+		}
+	}
+}