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，可以向当前所有用户广播通知。

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();
    }
}

我需要从前端获取一些文本框输入 javascript 例如10038 这是用户 ID 并将其发送到服务器 class 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 return 一组由用户 ID 定义的针对特定用户的通知，但我似乎无法弄清楚如何映射响应，因此我只能 return 通知signalR 中的特定客户端。

如何将客户端的连接 ID 映射到输入的用户 ID？

我已经阅读了 signalR 文档，但它非常模糊，其他在线解决方案似乎也没有解决这个特定问题。

如有任何帮助，我们将不胜感激。

编辑

So far I have tried using IUserIdProvider and this is what I have so far but this does not seem to work.

On the front end I have set my queryString as follows

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

This is my custom IUserIdProvider

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

This is what my NotificationRepository looks like

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);
        }
    }
}

And this is my hub

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

So I've figured out what the issue is in this scenario. When initialising the queryString
$.connection.hub.qs = "userId=" + $('#userText').val();
You must do this before you start the connection to the hub.

SignalR 向特定客户端发送消息

SignalR send message to specific client

c#

asp.net

signalr

signalr-hub

编辑