Asp.net-core – UserId in SignalR Core

asp.net-coreasp.net-core-signalr

I'm using SignalR with ASP.NET Core 2.0 and I'm trying to send a notification for a specific user like this:

_notification.Clients.User(id).InvokeAsync("SendMes");

where _notification is IHubContext.
But it doesn't work. When I send the notification for all users, everything is fine and all users get the notification. But when I send it to a specific user, nothing happens. In connections I have needed user but it seems as if he doesn't have userId. So how can I do this? By access to Identity and claims? If so, how to do this?

Best Answer

I was facing a similar problem and the following article helped me figure it out: https://docs.microsoft.com/en-us/aspnet/core/signalr/groups?view=aspnetcore-2.1

In the Hub (server-side), I checked Context.UserIdentifier and it was null, even though the user was authenticated. It turns out that SignalR relies on ClaimTypes.NameIdentifier and I was only setting ClaimTypes.Name. So, basically I added another claim and it worked out (Context.UserIdentifier is set correctly after that).

Below, I share part of the authentication code I have, just in case it helps:

var claims = userRoles.Split(',', ';').Select(p => new Claim(ClaimTypes.Role, p.Trim())).ToList();
claims.Insert(0, new Claim(ClaimTypes.Name, userName));
claims.Insert(1, new Claim(ClaimTypes.NameIdentifier, userName)); // this is the claim type that is used by SignalR
var userIdentity = new ClaimsIdentity(claims, CookieAuthenticationDefaults.AuthenticationScheme);
ClaimsPrincipal principal = new ClaimsPrincipal(userIdentity);

Be careful, SignalR users and groups are case-sensitive.

Related Solutions

Git push origin master: ERROR: Disconnected: No supported authentication methods available

I ran into the same error message trying to get Git, Git Extensions, and GitHub working with 64-bit Windows 7. I was able to solve the problem while continuing to use Putty.

I created a .profile file in C:\Users\MyUserName with the following contents:

GIT_SSH="/c/Program Files (x86)/Git/bin/ssh.exe"

Had to use "touch .profile" within git bash to create the file since Windows GUI chastises you for trying to create files starting with period.

Can't take credit. I just put a windows spin on the answer provided here.

C# – Call SignalR Core Hub method from Controller

Solution 1

Another possibility is to inject your HubContext into your controller like:

public VarDesignCommController(IHubContext<VarDesignHub> hubcontext)
{
    HubContext = hubcontext;
    ...
}

private IHubContext<VarDesignHub> HubContext
{ get; set; }

Then you can also call

await this.HubContext.Clients.All.InvokeAsync("Completed", id);

But then you will direct call methods on all clients.

Solution 2

You can also work with typed hubs: Simple create an interface where you define which methods your server can call on the clients:

public interface ITypedHubClient
{
    Task BroadcastMessage(string name, string message);
}

Inherit from Hub:

public class ChatHub : Hub<ITypedHubClient>
{
    public void Send(string name, string message)
    {
        Clients.All.BroadcastMessage(name, message);
    }
}

Inject your the typed hubcontext into your controller, and work with it:

[Route("api/demo")]
public class DemoController : Controller
{
    IHubContext<ChatHub, ITypedHubClient> _chatHubContext;
    public DemoController(IHubContext<ChatHub, ITypedHubClient> chatHubContext)
    {
        _chatHubContext = chatHubContext;
    }

    // GET: api/values
    [HttpGet]
    public IEnumerable<string> Get()
    {
        _chatHubContext.Clients.All.BroadcastMessage("test", "test");
        return new string[] { "value1", "value2" };
    }
}

Best Answer

Related Solutions

Git push origin master: ERROR: Disconnected: No supported authentication methods available

C# – Call SignalR Core Hub method from Controller

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