type Client struct {
    conn *websocket.Conn
    send chan []byte
    username string
}
<p>type Message struct {
Type string <code>json:"type"</code> // "public", "private"
From string <code>json:"from"</code>
To   string <code>json:"to,omitempty"</code>
Body string <code>json:"body"</code>
}</p>

var clients = make(map[*Client]bool)
var mutex sync.Mutex
var broadcast = make(chan []byte)

func registerClient(client *Client) {
    mutex.Lock()
    defer mutex.Unlock()
    clients[client] = true
}

func handleMessages() {
    for message := range broadcast {
        var msg Message
        if err := json.Unmarshal(message, &msg); err != nil {
            continue
        }
<pre class='brush:php;toolbar:false;'>    if msg.Type == "private" {
        mutex.Lock()
        for client := range clients {
            if client.username == msg.To {
                select {
                case client.send <- message:
                default:
                    close(client.send)
                    delete(clients, client)
                }
            }
        }
        mutex.Unlock()
    } else {
        // 公聊广播给所有人
        mutex.Lock()
        for client := range clients {
            select {
            case client.send <- message:
            default:
                close(client.send)
                delete(clients, client)
            }
        }
        mutex.Unlock()
    }
}

}

{
  "type": "private",
  "from": "alice",
  "to": "bob",
  "body": "你好，这是私密消息"
}