How to send message to specific group in asp.net core using signalr?

Question

In my asp.net core 3.1 application I am using signalr for sending messages and angular for UI. So for now Everyone can see messages, I would like to send message only for appropriate organizations can see. For ex: I have 2 organizations, org1 and org2. In org1 there are 4 users and in org2 it is 5 users. I would like to send messages for ex: org1 user loggedin and only 4 users should notified. I have getCurrentOrgId as well.

My NotificationHub Class looks like:

 public class NotificationHub : Hub
    {
        public async Task SendMessage(string user, string message)
        {
            await Clients.All.SendAsync("ReceiveMessage", user, message);
        }
    }

And I am using HubContext to send message:

  private readonly IHubContext<NotificationHub> _hubContext;

  await _hubContext.Clients.All.SendAsync("ReceiveMessage",$"{notificationToAdd.ActionMessage}", cancellationToken: cancellationToken);

// I would like some organizationGroup and send messages only loggedinuser orgId == getCurrentOrgId. Only users for appropriate organization can see notification orgId2 users should not see orgId1 users notification.

Does this answer your question? SignalR .Net client: How do I send a message to a Group? — Ali Dehqan
– Ali Dehqan, Commented Jul 15, 2020 at 13:04
@ArzuSuleymanov The code i posted doesn't answer you question ? — HMZ
– HMZ, Commented Jul 15, 2020 at 14:27
@ArzuSuleymanov if you want to send a message to a specific user you can use the UserId using Clients.User(userId).SendAsync(), you can use a static ConcurrentDictionary to store groups and users information like connection ids as keys and values, also you can cache the groups and connectionIds in the server cache using the OnConnected via a Dictionary and then access them outside the hub if you wish. — HMZ
– HMZ, Commented Jul 15, 2020 at 17:44

HMZ · Accepted Answer · 2020-07-15 11:29:48Z

This is a sample of what a hub with groups might look like :

    public class NotificationHub : Hub
    {
        private readonly UserManager<ApplicationUser> userManager;

        public NotificationHub(UserManager<ApplicationUser> userManager)
        {
            this.userManager = userManager;
        }

        public async override Task OnConnectedAsync()
        {
            var user = await userManager.FindByNameAsync(Context.User.Identity.Name);

            if (user != null)
            {
                if (user.UserType == UserType.Administrator)
                {
                    await AddToGroup("Administrators");
                }
                else if (user.UserType == UserType.Employee)
                {
                    await AddToGroup("Employees");
                }
            }
            else
            {
                await Clients.Caller.SendAsync("ReceiveNotification", "Connection Error", 0);
            }
        }


        public async Task SendNotification(string group, string message, int messageType)
        {
            await Clients.Group(group).SendAsync("ReceiveNotification", message, messageType);
        }

        public async Task AddToGroup(string groupName)
        {
            await Groups.AddToGroupAsync(Context.ConnectionId, groupName);
        }

        public async Task RemoveFromGroup(string groupName)
        {
            await Groups.RemoveFromGroupAsync(Context.ConnectionId, groupName);
        }
    }

I have an extra enum in ApplicationUser called UserType which i use to add users to groups on connect.

Collectives™ on Stack Overflow

How to send message to specific group in asp.net core using signalr?

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related