xPushService/Providers/XPushServiceUserNameProvider.cs

using Microsoft.AspNetCore.SignalR;

namespace xPushService.Providers {
    public class XPushServiceUserNameProvider : IUserIdProvider {
        public string GetUserId (HubConnectionContext connection) {
            //
            var result = connection.User?.Identity?.Name;
            return result;
        }
    }
}