Golang长连接如何维护 使用心跳机制保持TCP连接存活

type Connection struct {
    conn    net.Conn
    lastActive time.Time
    mu      sync.Mutex
}

func (c *Connection) updateLastActive() {
    c.mu.Lock()
    defer c.mu.Unlock()
    c.lastActive = time.Now()
}

func (c *Connection) isTimeout(timeout time.Duration) bool {
    c.mu.Lock()
    defer c.mu.Unlock()
    return time.Since(c.lastActive) > timeout
}

func (c *Connection) startHeartbeat(interval, timeout time.Duration) {
    ticker := time.NewTicker(interval)
    defer ticker.Stop()

    for {
        select {
        case <-ticker.C:
            // 发送 ping 消息
            if _, err := c.conn.Write([]byte("ping\n")); err != nil {
                log.Println("心跳发送失败:", err)
                c.conn.Close()
                return
            }
            c.updateLastActive()

        case <-time.After(timeout): // 等待响应超时处理（可结合 pong 回复）
            // 如果期望服务端回复 pong，这里可以增加等待逻辑
            // 实际中可用 context 或 channel 控制
        }
    }
}

func handleConnection(conn net.Conn) {
    client := &Connection{conn: conn, lastActive: time.Now()}

    go client.startHeartbeat(30*time.Second, 10*time.Second) // 客户端每30秒发一次

    buffer := make([]byte, 1024)
    for {
        conn.SetReadDeadline(time.Now().Add(60 * time.Second)) // 设置读超时
        n, err := conn.Read(buffer)
        if err != nil {
            log.Println("连接读取错误:", err)
            conn.Close()
            return
        }

        msg := string(buffer[:n])
        if strings.TrimSpace(msg) == "ping" {
            conn.Write([]byte("pong\n"))
            client.updateLastActive()
        } else if strings.TrimSpace(msg) == "pong" {
            // 客户端收到服务端的 pong 回应（如果是双向心跳）
        }
    }
}

func (s *Server) cleanupConnections() {
    ticker := time.NewTicker(60 * time.Second)
    defer ticker.Stop()

    for range ticker.C {
        now := time.Now()
        s.mu.Lock()
        for id, conn := range s.conns {
            if conn.isTimeout(90 * time.Second) { // 比如 90 秒未活动
                log.Printf("关闭超时连接: %s", id)
                conn.conn.Close()
                delete(s.conns, id)
            }
        }
        s.mu.Unlock()
    }
}

tcpConn, _ := net.Dial("tcp", "localhost:8080")
if tcp, ok := tcpConn.(*net.TCPConn); ok {
    tcp.SetKeepAlive(true)
    tcp.SetKeepAlivePeriod(30 * time.Second)
}