package localchat import ( "encoding/json" "fmt" "godo/libs" "log" "net" "os" "strings" "time" ) type UdpMessage struct { Type string `json:"type"` IP string `json:"ip"` Hostname string `json:"hostname"` Message interface{} `json:"message"` } var OnlineUsers = make(map[string]UdpMessage) // SendBroadcast 发送广播消息 func init() { go InitBroadcast() go ListenForBroadcast() } func InitBroadcast() { ticker := time.NewTicker(5 * time.Second) // 每 5 秒发送一次广播消息 defer ticker.Stop() for range ticker.C { hostname, err := os.Hostname() if err != nil { log.Printf("Failed to get hostname: %v", err) continue } message := UdpMessage{ Type: "online", Hostname: hostname, Message: "", } //发送多播消息 //broadcastAddr := GetBroadcastAddr() err = SendBroadcast("224.0.0.251:20249", message) if err != nil { log.Println("Failed to send broadcast message:", err) } err = SendBroadcast("255.255.255.255:20249", message) if err != nil { log.Println("Failed to send broadcast message:", err) } } } // SendToIP 向指定的 IP 地址发送 UDP 消息 func SendToIP(message UdpMessage) error { toIp := message.IP port := GetBroadcastPort() addr, err := net.ResolveUDPAddr("udp4", fmt.Sprintf("%s:%s", toIp, port)) if err != nil { log.Printf("Failed to resolve UDP address %s:%s: %v", toIp, port, err) return err } // 使用本地地址进行连接 localAddr, err := net.ResolveUDPAddr("udp4", "0.0.0.0:0") if err != nil { log.Printf("Failed to resolve local UDP address: %v", err) return err } conn, err := net.ListenUDP("udp4", localAddr) if err != nil { log.Printf("Failed to listen on UDP address %s: %v", toIp, err) return err } defer conn.Close() // 获取本地 IP 地址 localIP, err := GetLocalIP() if err != nil { log.Printf("Failed to get local IP address: %v", err) return err } message.IP = localIP data, err := json.Marshal(message) if err != nil { log.Printf("Failed to marshal JSON for %s: %v", toIp, err) return err } _, err = conn.WriteToUDP(data, addr) if err != nil { log.Printf("Failed to write to UDP address %s: %v", toIp, err) return err } log.Printf("发送 UDP 消息到 %s 成功", toIp) return nil } // 获取 OnlineUsers 的最新状态 func GetOnlineUsers() map[string]UdpMessage { return OnlineUsers } func GetLocalIP() (string, error) { return libs.GetIPAddress() } func GetBroadcastPort() string { addr := GetBroadcastAddr() return addr[strings.LastIndex(addr, ":")+1:] }