SignalR 向特定客户端发送消息

Question

我有一个带有静态方法的集线器，该方法当前向所有用户广播通知。

public class NotificationHub : Hub
{
    private static string connString = ConfigurationManager.ConnectionStrings["DefaultConnection"].ToString();

    [HubMethodName("sendNotifications")]
    public static void SendNotifications()
    {
        IHubContext context = GlobalHost.ConnectionManager.GetHubContext<NotificationHub>();
        context.Clients.All.updateNotifications();
    }
}

我需要从前端 javascript 获取一些文本框输入，例如10038 是用户 ID，并将其发送到服务器类，例如

public class NotificationRepository
{
    private readonly string _connString = ConfigurationManager.ConnectionStrings["DefaultConnection"].ConnectionString;

    public IEnumerable<Notifications> GetNotifications(int userID)
    {
        var notifications = new List<Notifications>();

        using (var connection = new SqlConnection(_connString))
        {
            connection.Open();
            using (var command = new SqlCommand(String.Format(@"SELECT [ID], [UserID], [Message] FROM [dbo].[Notification] WHERE [UserID] = {0}", userID), connection))
            {
                command.Notification = null;

                var dependency = new SqlDependency(command);
                dependency.OnChange += new OnChangeEventHandler(dependency_OnChange);

                if (connection.State == ConnectionState.Closed)
                {
                    connection.Open();
                }

                var reader = command.ExecuteReader();

                while (reader.Read())
                {
                    notifications.Add(item: new Notifications { ID = (int)reader["ID"], UserID = (int)reader["UserID"], Message = (string)reader["Message"] });
                }
            }
        }
        return notifications;
    }

    private void dependency_OnChange(object sender, SqlNotificationEventArgs e)
    {
        if (e.Type == SqlNotificationType.Change)
        {
            NotificationHub.SendNotifications();
        }
    }
}

我返回一组由用户 ID 定义的特定用户的通知，但我似乎无法弄清楚我如何映射响应，因此我只在 signalR 中向该特定客户端返回通知。

如何将客户端的连接 ID 映射到输入的用户 ID？

我已阅读 signalR 文档，但内容非常模糊，其他在线解决方案似乎无法解决此特定问题。

任何帮助将不胜感激。

编辑

到目前为止，我已经尝试过使用 IUserIdProvider，这是我目前所拥有的，但这似乎不起作用。

在前端，我将我的 queryString 设置如下

$.connection.hub.qs = "userId=" + $('#userText').val();

这是我的自定义 IUserIdProvider

public class CustomUserIdProvider : IUserIdProvider
{
    public string GetUserId(IRequest request)
    {
         return request.QueryString["userId"];
     }
 }

这就是我的 NotificationRepository 的样子

public class NotificationRepository
{
    private readonly string _connString = ConfigurationManager.ConnectionStrings["DefaultConnection"].ConnectionString;

    public IEnumerable<Notifications> GetUserNotifications(string userID)
    {
        var notifications = new List<Notifications>();

        using (var connection = new SqlConnection(_connString))
        {
            connection.Open();
            using (var command = new SqlCommand(String.Format(@"SELECT [ID], [UserID], [Message] FROM [dbo].[Notification] WHERE [UserID] = {0}", userID), connection))
            {
                command.Notification = null;

                var dependency = new SqlDependency(command);
                dependency.OnChange += new OnChangeEventHandler((sender, e) => dependency_OnChange(sender, e, userID));

                if (connection.State == ConnectionState.Closed)
                {
                    connection.Open();
                }

                var reader = command.ExecuteReader();

                while (reader.Read())
                {
                    notifications.Add(item: new Notifications { ID = (int)reader["ID"], UserID = (int)reader["UserID"], Message = (string)reader["Message"] });
                }
            }
        }
        return notifications;
    }


    private void dependency_OnChange(object sender, SqlNotificationEventArgs e, string userID)
    {
        if (e.Type == SqlNotificationType.Change)
        {
            NotificationHub.SendNotifications(userID);
        }
    }
}

这是我的中心

public class NotificationHub : Hub
{
    private static string connString = ConfigurationManager.ConnectionStrings["DefaultConnection"].ToString();

    [HubMethodName("sendNotifications")]
    public static void SendNotifications(string userId)
    {
        IHubContext context = GlobalHost.ConnectionManager.GetHubContext<NotificationHub>();
        context.Clients.Client(userId).updateNotifications();
    }
}

Answer 1

所以我已经弄清楚了这种情况下的问题所在。什么时候 初始化查询字符串

$.connection.hub.qs = "userId=" + $('#userText').val();

您必须在开始连接到集线器之前执行此操作。