ClientApiPoC/Shared/SignalR/TunnelServerBase.cs

using Microsoft.AspNetCore.SignalR;

namespace ClientApiPoC.Shared.SignalR {
    public abstract class TunnelServerBase {
        protected IHubContext<TunnelHub> HubContext { get; private set; }

        protected ClientTracker Clients { get; private set; }

        public TunnelServerBase(IHubContext<TunnelHub> hubContext, ClientTracker clientTracker) {
            if (hubContext == null) throw new ArgumentNullException(nameof(hubContext));
            if (clientTracker == null) throw new ArgumentNullException(nameof(clientTracker));
            this.HubContext = hubContext;
            this.Clients = clientTracker;
        }

        protected ISingleClientProxy? TryGetClient(string clientId) {
            ISingleClientProxy? client;
            try {
                client = this.HubContext.Clients.Client(clientId);
            } catch {
                client = null;
            }
            return client;
        }

        protected IDictionary<string, ISingleClientProxy> GetAllClients() {
            var results = new Dictionary<string, ISingleClientProxy>();
            var allClientIds = this.Clients.CurrentClientIds;
            foreach (var clientId in allClientIds) {
                var client = TryGetClient(clientId);
                if (client != null) results.Add(clientId, client);
            }
            return results;
        }
    }
}