用Gorilla Websocket 搞一个聊天室

// AliveList 当前在线列表
type AliveList struct {
	ConnList  map[string]*Client
	register  chan *Client
	destroy   chan *Client
	broadcast chan Message
	cancel    chan int
	Len       int
}

// Client socket客户端
type Client struct {
	ID     string
	conn   *websocket.Conn
	cancel chan int
}

// 启动监听
func (al *AliveList) run() {
	log.Println("开始监听注册事件")
	for {
		select {
		case client := <-al.register:
			log.Println("注册事件:", client.ID)
			al.ConnList[client.ID] = client
			al.Len++
			al.SysBroadcast(ConnectedMessage, Message{
				ID:      client.ID,
				Content: "connected",
				SentAt:  time.Now().Unix(),
			})

		case client := <-al.destroy:
			log.Println("销毁事件:", client.ID)
			err := client.conn.Close()
			if err != nil {
				log.Printf("destroy Error: %v \n", err)
			}
			delete(al.ConnList, client.ID)
			al.Len--

		case message := <-al.broadcast:
			log.Printf("广播事件: %s %s %d \n", message.ID, message.Content, message.Type)
			for id := range al.ConnList {
				if id != message.ID {

					err := al.sendMessage(id, message)
					if err != nil {
						log.Println("broadcastError: ", err)
					}
				}
			}

		case sign := <-al.cancel:
			log.Println("终止事件: ", sign)
			os.Exit(0)
		}
	}
}

const (
	// SystemMessage 系统消息
	SystemMessage = iota
	// BroadcastMessage 广播消息(正常的消息)
	BroadcastMessage
	// HeartBeatMessage 心跳消息
	HeartBeatMessage
	// ConnectedMessage 上线通知
	ConnectedMessage
	// DisconnectedMessage 下线通知
	DisconnectedMessage
)



// Message 消息体结构
type Message struct {
	ID      string
	Content string
	SentAt  int64
	Type    int     // <- SystemMessage 等类型就是这里了
}