From 57c77e7d0790725367ea2db15130ad71485b90a8 Mon Sep 17 00:00:00 2001
From: Erik Brakkee <erik@brakkee.org>
Date: Sun, 18 Aug 2024 11:44:16 +0200
Subject: [PATCH] initial state is now sent again when the websocket connection
 is established. Also throttling based on user input. When browser sends
 multiple messages per second the user will still only get one notification
 per second at most.

---
 pkg/server/ui/websessions.go | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/pkg/server/ui/websessions.go b/pkg/server/ui/websessions.go
index 8fac497..0075ee8 100644
--- a/pkg/server/ui/websessions.go
+++ b/pkg/server/ui/websessions.go
@@ -3,6 +3,7 @@ package ui
 import (
 	"context"
 	"git.wamblee.org/converge/pkg/models"
+	"git.wamblee.org/converge/pkg/support/throttling"
 	"log"
 	"net"
 	"net/http"
@@ -24,7 +25,8 @@ type WebSession struct {
 
 func NewWebSessions(notifications chan *models.State) *WebSessions {
 	websessions := &WebSessions{
-		sessions: make(map[*WebSession]bool),
+		sessions:         make(map[*WebSession]bool),
+		lastNotification: models.NewState(),
 	}
 
 	go func() {
@@ -76,7 +78,16 @@ func (sessions *WebSessions) NewSession(wsConnection net.Conn, ctx context.Conte
 		conn:          wsConnection,
 		ctx:           ctx,
 	}
+
+	// initial notification as soon as client connects.
 	go func() {
+		session.notifications <- sessions.lastNotification
+	}()
+
+	go func() {
+		throttler := throttling.NewAsyncThrottler(func(state *models.State) {
+			session.notifications <- state
+		}, time.Second, time.Second)
 		for {
 			// the web app opens one websocket connection and sends a hello
 			// message asking for the latest state when a page is loaded that requires this.
@@ -84,7 +95,7 @@ func (sessions *WebSessions) NewSession(wsConnection net.Conn, ctx context.Conte
 			p := make([]byte, 1024)
 			_, err := wsConnection.Read(p)
 			if err == nil {
-				session.notifications <- sessions.lastNotification
+				throttler.Notify(sessions.lastNotification)
 			} else {
 				log.Printf("Got error reading %v", err)
 				cancel()