c# - SignalR(v2.2.0) OnDisconnected 设置用户离线

Question

我正在使用以下代码将用户添加到组中，并使用以下代码将用户保存到该特定组的数据库中。

服务器:

  public class ChatHub : Hub
{


    public async Task JoinRoom(string user_Id, string room_Id, string user_Name)
    {
        AddLoginUser(room_Id, this.Context.ConnectionId, user_Id);
        await this.Groups.Add(this.Context.ConnectionId, room_Id);
    }


    public void Connect(string user_Id, string room_Id, string user_Name)
    {
        var id = Context.ConnectionId;

        Clients.Caller.onConnected(id, user_Name, GetRoomUser(room_Id), GetRoomMessage(room_Id));

        // send to all in group to update user list
        Clients.OthersInGroup(room_Id).onNewUserConnected(id, user_Name);
    }
  public override System.Threading.Tasks.Task OnDisconnected(bool stopCalled)
    {

        using (DataContext dc = new DataContext())
        {
            var item = dc.LoggedInUsers.FirstOrDefault(x => x.ConnectionId == Context.ConnectionId);
            if (item != null)
            {
                item.Connected = false;
                dc.SubmitChanges();

                Clients.OthersInGroup(item.RoomID.ToString()).onUserDisconnected(Context.ConnectionId, item.UserMaster.User_Name);
            }

            return base.OnDisconnected(stopCalled);
        }
    }
   }

 private void AddLoginUser(string room_Id, string connection_Id, string user_Id)
    {
        using (DataContext dc = new DataContext())
        {
            var checkUserLogedIn = (from user in dc.LoggedInUsers
                                    where (user.RoomID == Convert.ToInt32(room_Id) && user.UserID == Convert.ToInt32(user_Id))
                                    select user).SingleOrDefault();
            if (checkUserLogedIn == null)
            {
                LoggedInUser objLoggedInUser = new LoggedInUser();
                objLoggedInUser.ConnectionId = connection_Id;
                objLoggedInUser.UserID = Convert.ToInt32(user_Id);
                objLoggedInUser.RoomID = Convert.ToInt32(room_Id);
                objLoggedInUser.Connected = true;
                dc.LoggedInUsers.InsertOnSubmit(objLoggedInUser);
                dc.SubmitChanges();
            }
            else
            {
                if (!checkUserLogedIn.Connected)
                {
                    checkUserLogedIn.Connected = true;
                    dc.SubmitChanges();
                }
            }
        }
    }

问题:

假设我使用 roomid=1 和 contextid=123asd 的 userid=1 登录。如果我刷新我的窗口然后 contextid 将更改，现在如果我关闭浏览器选项卡然后查询:

var item = dc.LoggedInUsers.FirstOrDefault(x => x.ConnectionId == Context.ConnectionId);

没有根据最新的 connectionid 找出用户，因为当我在连接上保存用户时 connectionid 是不同的。

如何在断开连接事件中为特定用户设置连接状态为 false。

提前致谢。

Answer 1

OnConnected 你应该保存所有 connectionIds(与用户映射)，connectionId 应该是唯一的，而不是用户。因为一个用户可以同时有多个连接到 signalr(新标签)。

每次你应该在 Onconnected 上映射用户和 connectionId。每次您应该只删除该 connectionId，而不是 OnDisconnected 上用户的所有 connectionId。如果用户不在列表中(如果未调用停止调用，即使用户未断开连接也可能发生断开连接)，您应该在 OnReconnected 上添加 connectionId。

您应该以此为基础重构您的代码库。首先，您应该删除 connectionId。然后，您可以检查；如果列表中没有此用户(与该connectionId映射)的记录，则可以发送消息。

检查 here

我已经稍微修改了你的代码，你可以根据这些知识改进这段代码。您还应该在 OnReconnected 上调用 AddLoginUser。

     public override System.Threading.Tasks.Task OnDisconnected(bool stopCalled)
                {
                    using (DataContext dc = new DataContext())
                    {
                        var item = dc.LoggedInUsers.FirstOrDefault(x => x.ConnectionId == Context.ConnectionId);
                        if (item != null)
                        {
                            dc.LoggedInUsers.Remove(item);
                            dc.SubmitChanges();
//If there is no other connection left with this user in this room send message.
                               if (!dc.LoggedInUsers.Any(x => x.RoomID==item.RoomID && x.userId==item.UserId)
                                   Clients.OthersInGrouproomId.ToString()).onUserDisconnected(Context.ConnectionId, item.UserMaster.User_Name);
                           }
                        return base.OnDisconnected(stopCalled);
                    }
                }
            }

            private void AddLoginUser(string room_Id, string connection_Id, string user_Id)
            {
                using (DataContext dc = new DataContext())
                {
//Just check connectionId uniqunes. You don't need connected field.
                    var checkUserLogedIn = (from user in dc.LoggedInUsers
                                            where user.ConnectionId == connection_Id
                                            select user).SingleOrDefault();
                    if (checkUserLogedIn == null)
                    {
                        LoggedInUser objLoggedInUser = new LoggedInUser();
                        objLoggedInUser.ConnectionId = connection_Id;
                        objLoggedInUser.UserID = Convert.ToInt32(user_Id);
                        objLoggedInUser.RoomID = Convert.ToInt32(room_Id);
                        dc.LoggedInUsers.InsertOnSubmit(objLoggedInUser);
                        dc.SubmitChanges();
                    }
                }
            }