added application example for using the javascript interface.

app/backend/go.mod

@@ -0,0 +1,7 @@
+module server
+
+go 1.19
+
+require github.com/gorilla/websocket v1.5.1
+
+require golang.org/x/net v0.17.0 // indirect

app/backend/go.sum

@@ -0,0 +1,4 @@
+github.com/gorilla/websocket v1.5.1 h1:gmztn0JnHVt9JZquRuzLw3g4wouNVzKL15iLr/zn/QY=
+github.com/gorilla/websocket v1.5.1/go.mod h1:x3kM2JMyaluk02fnUJpQuwD2dCS5NDG2ZHL0uE0tcaY=
+golang.org/x/net v0.17.0 h1:pVaXccu2ozPjCXewfr1S7xza/zcXTity9cCdXQYSjIM=
+golang.org/x/net v0.17.0/go.mod h1:NxSsAGuq816PNPmqtQdLE42eU2Fs7NoRIZrHJAlaCOE=

app/backend/main.go

@@ -0,0 +1,123 @@
+package main
+
+import (
+	"encoding/json"
+	"log"
+	"net/http"
+	"sync"
+	"time"
+
+	"github.com/gorilla/websocket"
+)
+
+type Message struct {
+	Type string `json:"type"`
+	Room string `json:"room"`
+	Text string `json:"text"`
+}
+
+type RoomManager struct {
+	rooms map[string]map[*websocket.Conn]bool
+	mutex sync.RWMutex
+}
+
+func NewRoomManager() *RoomManager {
+	return &RoomManager{
+		rooms: make(map[string]map[*websocket.Conn]bool),
+	}
+}
+
+func (rm *RoomManager) AddClientToRoom(room string, client *websocket.Conn) {
+	rm.mutex.Lock()
+	defer rm.mutex.Unlock()
+
+	if rm.rooms[room] == nil {
+		rm.rooms[room] = make(map[*websocket.Conn]bool)
+	}
+	rm.rooms[room][client] = true
+	log.Printf("[%s] client added to room %s\n", time.Now().UTC().Format(time.RFC3339), room)
+}
+
+func (rm *RoomManager) RemoveClientFromRoom(room string, client *websocket.Conn) {
+	rm.mutex.Lock()
+	defer rm.mutex.Unlock()
+
+	if rm.rooms[room] != nil {
+		delete(rm.rooms[room], client)
+		if len(rm.rooms[room]) == 0 {
+			delete(rm.rooms, room)
+			log.Printf("[%s] room %s is now empty and removed\n", time.Now().UTC().Format(time.RFC3339), room)
+		}
+	}
+}
+
+func (rm *RoomManager) BroadcastMessage(room string, message []byte, sender *websocket.Conn) {
+	rm.mutex.RLock()
+	defer rm.mutex.RUnlock()
+
+	if rm.rooms[room] != nil {
+		for client := range rm.rooms[room] {
+			if client != sender {
+				go func(c *websocket.Conn) {
+					if err := c.WriteMessage(websocket.TextMessage, message); err != nil {
+						log.Printf("[%s] error broadcasting message to client: %v\n", time.Now().UTC().Format(time.RFC3339), err)
+						rm.RemoveClientFromRoom(room, c)
+					}
+				}(client)
+			}
+		}
+		log.Printf("[%s] message broadcasted to room %s\n", time.Now().UTC().Format(time.RFC3339), room)
+	}
+}
+
+func wsHandler(rm *RoomManager, w http.ResponseWriter, r *http.Request) {
+	upgrader := websocket.Upgrader{
+		CheckOrigin: func(r *http.Request) bool {
+			// Allow all connections by default
+			return true
+		},
+	}
+
+	conn, err := upgrader.Upgrade(w, r, nil)
+	if err != nil {
+		log.Printf("[%s] error upgrading to websocket: %v\n", time.Now().UTC().Format(time.RFC3339), err)
+		return
+	}
+	defer conn.Close()
+
+	for {
+		_, message, err := conn.ReadMessage()
+		if err != nil {
+			log.Printf("[%s] error reading message: %v\n", time.Now().UTC().Format(time.RFC3339), err)
+			rm.RemoveClientFromRoom("", conn)
+			break
+		}
+
+		var msg Message
+		if err := json.Unmarshal(message, &msg); err != nil {
+			log.Printf("[%s] error unmarshalling message: %v\n", time.Now().UTC().Format(time.RFC3339), err)
+			continue
+		}
+
+		switch msg.Type {
+		case "join":
+			rm.AddClientToRoom(msg.Room, conn)
+		case "text":
+			go rm.BroadcastMessage(msg.Room, message, conn)
+		case "audio":
+			go rm.BroadcastMessage(msg.Room, message, conn)
+		default:
+			log.Printf("[%s] invalid message type: %s\n", time.Now().UTC().Format(time.RFC3339), msg.Type)
+		}
+	}
+}
+
+func main() {
+	rm := NewRoomManager()
+
+	http.HandleFunc("/ws", func(w http.ResponseWriter, r *http.Request) {
+		wsHandler(rm, w, r)
+	})
+	log.SetFlags(0)
+	log.Fatal(http.ListenAndServe(":8080", nil))
+}