golang에서 WebSocket 양방향 통신을 구현하는 방법

import (
    "log"
    "net/http"

    "github.com/gorilla/websocket"
)

func websocketHandler(w http.ResponseWriter, r *http.Request) {
    // 将 HTTP 连接升级为 WebSocket 连接
    ws, err := upgrader.Upgrade(w, r, nil)
    if err != nil {
        log.Println("Error upgrading HTTP connection to WebSocket:", err)
        return
    }

    // 在连接结束时关闭 WebSocket
    defer ws.Close()

    // 循环处理客户端发来的消息
    for {
        // 读取客户端发来的消息
        messageType, message, err := ws.ReadMessage()
        if err != nil {
            log.Println("Error reading message from WebSocket:", err)
            break
        }

        // 打印收到的消息
        log.Printf("Received message: %s", message)

        // 回复客户端收到的消息
        if err = ws.WriteMessage(messageType, message); err != nil {
            log.Println("Error writing message to WebSocket:", err)
            break
        }
    }
}

var upgrader = websocket.Upgrader{
    // 允许跨域访问
    CheckOrigin: func(r *http.Request) bool {
        return true
    },
}

func main() {
    // 设置 WebSocket 处理函数
    http.HandleFunc("/", websocketHandler)

    // 启动 HTTP 服务器
    err := http.ListenAndServe(":8080", nil)
    if err != nil {
        log.Fatal("Error starting HTTP server:", err)
    }
}

const socket = new WebSocket("ws://localhost:8080/");

socket.addEventListener("open", (event) => {
    socket.send("Hello, server!");
});

socket.addEventListener("message", (event) => {
    console.log("Received message from server:", event.data);
});

socket.addEventListener("close", (event) => {
    console.log("Server connection closed:", event);
});