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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:]
}