Disconnect client from IHubContext<THub>

Question

I can call InvokeAsync from server code using the IHubContext interface, but sometimes I want to force these clients to disconnect.

So, is there any way to disconnect clients from server code that references the IHubContext interface?

Answer 1

Step 1:

using Microsoft.AspNetCore.Connections.Features;
using System.Collections.Generic;
using Microsoft.AspNetCore.SignalR;

public class ErrorService
{
    readonly HashSet<string> PendingConnections = new HashSet<string>();
    readonly object PendingConnectionsLock = new object();

    public void KickClient(string ConnectionId)
    {
        //TODO: log
        if (!PendingConnections.Contains(ConnectionId))
        {
            lock (PendingConnectionsLock)
            {
                PendingConnections.Add(ConnectionId);
            }
        }
    }

    public void InitConnectionMonitoring(HubCallerContext Context)
    {
        var feature = Context.Features.Get<IConnectionHeartbeatFeature>();

        feature.OnHeartbeat(state =>
        {
            if (PendingConnections.Contains(Context.ConnectionId))
            {
                Context.Abort();
                lock (PendingConnectionsLock)
                {
                    PendingConnections.Remove(Context.ConnectionId);
                }
            }

        }, Context.ConnectionId);
    }
}

Step 2:

    public void ConfigureServices(IServiceCollection services)
    {
        ...
        services.AddSingleton<ErrorService>();
        ...
    }

Step 3:

[Authorize(Policy = "Client")]
public class ClientHub : Hub
{
    ErrorService errorService;

    public ClientHub(ErrorService errorService)
    {
        this.errorService = errorService;
    }

    public async override Task OnConnectedAsync()
    {
        errorService.InitConnectionMonitoring(Context);
        await base.OnConnectedAsync();
    }
....

Disconnecting without Abort() method:

public class TestService
{
    public TestService(..., ErrorService errorService)
    {
        string ConnectionId = ...;
        errorService.KickClient(ConnectionId);