[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"academy-blogs-en-1-1-all-user-join-notification-websocket-chat-all--*":3,"academy-blog-translations-ifugg17ps3z64cx":99},{"data":4,"page":87,"perPage":87,"totalItems":87,"totalPages":87},[5],{"alt":6,"collectionId":7,"collectionName":8,"content":9,"cover_image":10,"cover_image_path":11,"created":12,"created_by":13,"expand":14,"id":94,"keywords":95,"locale":69,"published_at":96,"scheduled_at":13,"school_blog":91,"short_description":97,"status":89,"title":6,"updated":98,"updated_by":13,"slug":92,"views":93},"EP.45 Adding User Join Notification System in WebSocket Chat","sclblg987654321","school_blog_translations","\u003Ch3 data-pm-slice=\"1 1 []\">\u003Cspan>\u003Cstrong>Why Have a User Join Notification System?\u003C\u002Fstrong>\u003C\u002Fspan>\u003C\u002Fh3>\u003Cp>\u003Cspan>The User Join Notification system helps:\u003C\u002Fspan>\u003C\u002Fp>\u003Cul>\u003Cli>\u003Cstrong>Notify Existing Users: \u003C\u002Fstrong>Users in the chat room can be aware when new members join.\u003C\u002Fli>\u003Cli>\u003Cstrong>Encourage Interaction:\u003C\u002Fstrong> Fosters engagement among users, creating a lively chat environment.\u003C\u002Fli>\u003Cli>\u003Cstrong>Ideal for Community or Group Chats: \u003C\u002Fstrong>Makes it easier for members to greet and interact with newcomers.\u003C\u002Fli>\u003C\u002Ful>\u003Ch3>\u003Cspan>\u003Cstrong>Structure of the User Join Notification System in WebSocket Chat\u003C\u002Fstrong>\u003C\u002Fspan>\u003C\u002Fh3>\u003Col>\u003Cli>\u003Cstrong>WebSocket Server:\u003C\u002Fstrong> Detects new connections and broadcasts notifications to all users.\u003C\u002Fli>\u003Cli>\u003Cstrong>Frontend (Client-Side):\u003C\u002Fstrong> Displays notification messages when a new user joins.\u003C\u002Fli>\u003Cli>\u003Cstrong>Database (Optional):\u003C\u002Fstrong> Can store user join history for analysis purposes.\u003C\u002Fli>\u003C\u002Fol>\u003Ch3>\u003Cspan>\u003Cstrong>Adding the User Join Notification Feature to the WebSocket Server\u003C\u002Fstrong>\u003C\u002Fspan>\u003C\u002Fh3>\u003Ch4>\u003Cspan>\u003Cstrong>1. Upgrade the WebSocket Server to Support New User Notifications\u003C\u002Fstrong>\u003C\u002Fspan>\u003C\u002Fh4>\u003Cp>\u003Cspan>File: \u003C\u002Fspan>\u003Ccode>\u003Cspan>websocket_server.go\u003C\u002Fspan>\u003C\u002Fcode>\u003C\u002Fp>\u003Cpre>\u003Ccode class=\"language-plaintext\">package main\n\nimport (\n    \"encoding\u002Fjson\"\n    \"fmt\"\n    \"net\u002Fhttp\"\n    \"sync\"\n\n    \"github.com\u002Fgorilla\u002Fwebsocket\"\n)\n\ntype UserJoinNotification struct {\n    Username string `json:\"username\"`\n    Message  string `json:\"message\"`\n}\n\nvar upgrader = websocket.Upgrader{\n    CheckOrigin: func(r *http.Request) bool { return true },\n}\n\nvar (\n    clients   = make(map[*websocket.Conn]string)\n    broadcast = make(chan UserJoinNotification)\n    mu        sync.Mutex\n)\n\nfunc handleConnections(w http.ResponseWriter, r *http.Request) {\n    conn, _ := upgrader.Upgrade(w, r, nil)\n    defer conn.Close()\n    \n    var username string = r.URL.Query().Get(\"username\")\n    \n    mu.Lock()\n    clients[conn] = username\n    mu.Unlock()\n    \n    broadcast <- UserJoinNotification{Username: username, Message: fmt.Sprintf(\"%s เข้าร่วมแชทแล้ว!\", username)}\n    \n    for {\n        _, _, err := conn.ReadMessage()\n        if err != nil {\n            mu.Lock()\n            delete(clients, conn)\n            mu.Unlock()\n            break\n        }\n    }\n}\n\nfunc handleMessages() {\n    for {\n        notification := <-broadcast\n        fmt.Printf(\"User Joined: %s\\n\", notification.Message)\n        \n        for client := range clients {\n            err := client.WriteJSON(notification)\n            if err != nil {\n                client.Close()\n                mu.Lock()\n                delete(clients, client)\n                mu.Unlock()\n            }\n        }\n    }\n}\n\nfunc main() {\n    http.HandleFunc(\"\u002Fws\", handleConnections)\n    go handleMessages()\n    fmt.Println(\"WebSocket Server Running on Port 8080\")\n    http.ListenAndServe(\":8080\", nil)\n}\u003C\u002Fcode>\u003C\u002Fpre>\u003Ch3>\u003Cspan>\u003Cstrong>2. Adding User Join Notification Functionality in the Frontend (Client-Side)\u003C\u002Fstrong>\u003C\u002Fspan>\u003C\u002Fh3>\u003Cp>\u003Cspan>File: \u003C\u002Fspan>\u003Ccode>\u003Cspan>client.js\u003C\u002Fspan>\u003C\u002Fcode>\u003C\u002Fp>\u003Cpre>\u003Ccode class=\"language-plaintext\">const username = prompt(\"Enter your username:\");\nconst socket = new WebSocket(`ws:\u002F\u002Flocalhost:8080\u002Fws?username=${username}`);\nconst notificationsContainer = document.getElementById(\"notifications\");\n\nsocket.onmessage = (event) => {\n    const data = JSON.parse(event.data);\n    showNotification(data.message);\n};\n\nfunction showNotification(message) {\n    const notificationElement = document.createElement(\"p\");\n    notificationElement.innerText = message;\n    notificationsContainer.appendChild(notificationElement);\n}\u003C\u002Fcode>\u003C\u002Fpre>\u003Ch3>\u003Cspan>\u003Cstrong>Displaying User Join Notification on the UI\u003C\u002Fstrong>\u003C\u002Fspan>\u003C\u002Fh3>\u003Cp>\u003Cspan>File: \u003C\u002Fspan>\u003Ccode>\u003Cspan>index.html\u003C\u002Fspan>\u003C\u002Fcode>\u003C\u002Fp>\u003Cpre>\u003Ccode class=\"language-plaintext\"><div id=\"notifications\"><\u002Fdiv>\u003C\u002Fcode>\u003C\u002Fpre>\u003Ch3>\u003Cspan>\u003Cstrong>3. Testing the System\u003C\u002Fstrong>\u003C\u002Fspan>\u003C\u002Fh3>\u003Col data-spread=\"false\">\u003Cli>\u003Cspan>\u003Cstrong>Run the WebSocket Server\u003C\u002Fstrong>\u003C\u002Fspan>\u003C\u002Fli>\u003C\u002Fol>\u003Cpre>\u003Ccode class=\"language-plaintext\">go run websocket_server.go\u003C\u002Fcode>\u003C\u002Fpre>\u003Col data-spread=\"false\" start=\"2\">\u003Cli>\u003Cspan>\u003Cstrong>Open Multiple Browser Tabs and Log in with different usernames\u003C\u002Fstrong>\u003C\u002Fspan>\u003C\u002Fli>\u003Cli>\u003Cspan>\u003Cstrong>Observe Results at WebSocket Server and UI\u003C\u002Fstrong>\u003C\u002Fspan>\u003C\u002Fli>\u003C\u002Fol>\u003Ch3>\u003Cspan>\u003Cstrong>Challenge!\u003C\u002Fstrong>\u003C\u002Fspan>\u003C\u002Fh3>\u003Cp>\u003Cspan>Try adding \u003Cstrong>a User Leave Notification\u003C\u002Fstrong> system to inform chat members when someone exits the chat room. This will enhance the user experience by keeping everyone updated on who is present.\u003C\u002Fspan>\u003C\u002Fp>\u003Chr>\u003Ch3>\u003Cspan>\u003Cstrong>Next EP\u003C\u002Fstrong>\u003C\u002Fspan>\u003C\u002Fh3>\u003Cp>\u003Cspan>In EP.46, we will add \u003Cstrong>a Custom User Status feature in the WebSocket Chat! 🚀\u003C\u002Fstrong>\u003C\u002Fspan>\u003C\u002Fp>","62ei07st4388_aixa9bmjs6.webp","https:\u002F\u002Ftwsme-r2.tumwebsme.com\u002Fsclblg987654321\u002Fh2ge7fk12heb1gb\u002F62ei07st4388_aixa9bmjs6.webp","2026-03-04 08:50:56.881Z","",{"keywords":15,"locale":63,"school_blog":73},[16,23,28,33,38,43,48,53,58],{"collectionId":17,"collectionName":18,"created":19,"created_by":13,"id":20,"name":21,"updated":22,"updated_by":13},"sclkey987654321","school_keywords","2026-03-04 08:50:55.786Z","bn9tuj0554z99gg","Active Users","2026-04-10 16:14:30.249Z",{"collectionId":17,"collectionName":18,"created":24,"created_by":13,"id":25,"name":26,"updated":27,"updated_by":13},"2026-03-04 08:50:53.623Z","k6w6fyr98usbg2e","Chat Notifications","2026-04-10 16:14:29.576Z",{"collectionId":17,"collectionName":18,"created":29,"created_by":13,"id":30,"name":31,"updated":32,"updated_by":13},"2026-03-04 08:50:49.558Z","8lxakhujb04wz6u","Chat UX","2026-04-10 16:14:28.724Z",{"collectionId":17,"collectionName":18,"created":34,"created_by":13,"id":35,"name":36,"updated":37,"updated_by":13},"2026-03-04 08:48:07.088Z","brfbypclggbbkcx","WebSocket API","2026-04-10 16:13:40.594Z",{"collectionId":17,"collectionName":18,"created":39,"created_by":13,"id":40,"name":41,"updated":42,"updated_by":13},"2026-03-04 08:47:05.949Z","caufix9o52uw4bh","Real-Time Chat","2026-04-10 16:13:23.517Z",{"collectionId":17,"collectionName":18,"created":44,"created_by":13,"id":45,"name":46,"updated":47,"updated_by":13},"2026-03-04 08:20:14.253Z","ah6lvy4x8qe08l5","Golang","2026-04-10 16:07:26.172Z",{"collectionId":17,"collectionName":18,"created":49,"created_by":13,"id":50,"name":51,"updated":52,"updated_by":13},"2026-03-04 08:20:11.547Z","ey3puyme01a9bsw","Go","2026-04-10 16:07:25.893Z",{"collectionId":17,"collectionName":18,"created":54,"created_by":13,"id":55,"name":56,"updated":57,"updated_by":13},"2026-03-04 08:34:00.920Z","ecac9y661or1xka","WebSocket","2026-04-10 16:08:05.227Z",{"collectionId":17,"collectionName":18,"created":59,"created_by":13,"id":60,"name":61,"updated":62,"updated_by":13},"2026-03-04 08:50:56.096Z","pqk2xruvmm497x0","User Join Notification","2026-04-10 16:14:30.405Z",{"code":64,"collectionId":65,"collectionName":66,"created":67,"flag":68,"id":69,"is_default":70,"label":71,"updated":72},"en","pbc_1989393366","locales","2026-01-22 11:00:02.726Z","twemoji:flag-united-states","qv9c1llfov2d88z",false,"English","2026-04-10 15:42:46.825Z",{"category":74,"collectionId":75,"collectionName":76,"created":13,"expand":77,"id":91,"slug":92,"updated":13,"views":93},"wqxt7ag2gn7xcmk","pbc_2105096300","school_blogs",{"category":78},{"blogIds":79,"collectionId":80,"collectionName":81,"created":82,"created_by":13,"id":74,"image":83,"image_alt":13,"image_path":84,"label":85,"name":86,"priority":87,"publish_at":88,"scheduled_at":13,"status":89,"updated":90,"updated_by":13},[],"sclcatblg987654321","school_category_blogs","2026-03-04 08:33:53.210Z","59ty92ns80w_15oc1implw.png","https:\u002F\u002Ftwsme-r2.tumwebsme.com\u002Fsclcatblg987654321\u002Fwqxt7ag2gn7xcmk\u002F59ty92ns80w_15oc1implw.png",{"en":86,"th":86},"Golang The Series",1,"2026-03-16 04:39:38.440Z","published","2026-04-25 02:32:15.470Z","ifugg17ps3z64cx","user-join-notification-websocket-chat",233,"h2ge7fk12heb1gb",[20,25,30,35,40,45,50,55,60],"2025-03-24 01:51:51.004Z","Learn how to implement a User Join Notification system in WebSocket Chat that notifies all users in real-time when a new user joins the chat.","2026-05-06 08:38:37.394Z",{"th":92,"en":92}]