golang Websocket tutorial: How to develop online question and answer function

package main

import (
    "log"
    "net/http"

    "github.com/gorilla/websocket"
)

// 定义全局变量用于存储连接的客户端
var clients = make(map[*websocket.Conn]bool)

// 定义通道用于传递消息
var broadcast = make(chan Message)

// 定义消息结构体
type Message struct {
    Username string `json:"username"`
    Content  string `json:"content"`
}

// 定义升级HTTP请求为Websocket的方法
var upgrader = websocket.Upgrader{
    CheckOrigin: func(r *http.Request) bool {
        return true
    },
}

// 处理Websocket连接
func handleConnections(w http.ResponseWriter, r *http.Request) {
    conn, err := upgrader.Upgrade(w, r, nil)
    if err != nil {
        log.Fatal(err)
    }
    defer conn.Close()

    // 将连接的客户端添加到全局变量中
    clients[conn] = true

    for {
        var msg Message
        err := conn.ReadJSON(&msg)
        if err != nil {
            log.Printf("error: %v", err)
            delete(clients, conn)
            break
        }
        broadcast <- msg
    }
}

// 处理广播消息
func handleMessages() {
    for {
        msg := <-broadcast
        for client := range clients {
            err := client.WriteJSON(msg)
            if err != nil {
                log.Printf("error: %v", err)
                client.Close()
                delete(clients, client)
            }
        }
    }
}

func main() {
    http.HandleFunc("/ws", handleConnections)
    go handleMessages()
    log.Println("Server start on http://localhost:8000")
    log.Fatal(http.ListenAndServe(":8000", nil))
}

package main

import (
    "log"
    "net/url"
    "os"
    "os/signal"
    "time"

    "github.com/gorilla/websocket"
)

// 定义消息结构体
type Message struct {
    Username string
    Content  string
}

func main() {
    // 创建WebSocket连接
    u := url.URL{Scheme: "ws", Host: "localhost:8000", Path: "/ws"}
    c, _, err := websocket.DefaultDialer.Dial(u.String(), nil)
    if err != nil {
        log.Fatal("dial:", err)
    }
    defer c.Close()

    // 监听系统信号
    interrupt := make(chan os.Signal, 1)
    signal.Notify(interrupt, os.Interrupt)

    // 创建一个通道用于接收消息
    done := make(chan struct{})

    // 创建一个协程来监听用户输入并发送消息
    go func() {
        for {
            var msg Message
            err := c.ReadJSON(&msg)
            if err != nil {
                log.Println("read:", err)
                close(done)
                return
            }
            log.Printf("received: %v", msg)
        }
    }()

    // 创建一个协程来发送消息给服务器
    go func() {
        ticker := time.NewTicker(time.Second)
        defer ticker.Stop()

        for {
            select {
            case <-done:
                return
            case t := <-ticker.C:
                err := c.WriteJSON(Message{Username: "Alice", Content: "Hello, World!"})
                if err != nil {
                    log.Println("write:", err)
                    return
                }
                log.Printf("sent: %v", t.String())
            }
        }
    }()

    // 等待系统信号
    <-interrupt
    log.Println("interrupt")

    // 关闭连接
    err = c.WriteMessage(websocket.CloseMessage, websocket.FormatCloseMessage(websocket.CloseNormalClosure, ""))
    if err != nil {
        log.Println("write close:", err)
    }
    select {
    case <-done:
    case <-time.After(time.Second):
    }
    log.Println("server closed")
}