Disconnect client from IHubContext<THub> - asp.net-core-signalr

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);

Answer 2

In alpha 2 there is the Abort() on HubConnectionContext you could use to terminate a connection. I don't see, however, an easy way to access it from outside the hub.
Because you control the clients you could just invoke a client method and tell the client to disconnect. The advantage is that the client disconnect gracefully. The disadvantage is that it requires sending the message to the client instead of disconnecting the client solely on the server side.