Enha: sse update

broker/sse.go

@@ -1,6 +1,7 @@
 package broker
 
 import (
+	"context"
 	"fmt"
 	"log/slog"
 	"net/http"
@@ -20,8 +21,10 @@ type (
 	NotifierChan chan NotificationEvent
 	Broker       struct {
 		// Events are pushed to this channel by the main events-gathering routine
-		Notifier NotifierChan
-		log      *slog.Logger
+		Notifier  NotifierChan
+		log       *slog.Logger
+		addClient chan NotifierChan
+		clients   map[NotifierChan]struct{}
 	}
 )
 
@@ -33,6 +36,8 @@ func NewBroker() (broker *Broker) {
 			Level:     slog.LevelDebug,
 			AddSource: true,
 		})),
+		addClient: make(chan NotifierChan, 10),
+		clients:   map[NotifierChan]struct{}{},
 	}
 }
 
@@ -56,6 +61,8 @@ func (broker *Broker) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Access-Control-Allow-Origin", origin)
 	w.Header().Set("Access-Control-Allow-Credentials", "true")
 	ctx := r.Context()
+	msgChan := make(NotifierChan, 10)
+	broker.addClient <- msgChan
 	// browser can close sse on its own; ping every 2s to prevent
 	heartbeat := time.NewTicker(8 * time.Second)
 	defer heartbeat.Stop()
@@ -91,3 +98,15 @@ func (broker *Broker) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 }
+
+func (broker *Broker) Listen(ctx context.Context) {
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case clientChan := <-broker.addClient:
+			// mutex
+			broker.clients[clientChan] = struct{}{}
+		}
+	}
+}