title: How to send Parameter/Query in HubConnection SignalR Core 2.1
body: <p>I'm trying to send parameters into connection to <code>signalr</code></p>
  
  <pre><code>Connection = new HubConnectionBuilder()
                  .WithUrl("https://familyapp.azurewebsites.net/StoreHub?token=123")
                  .Build();
  
              await Connection.StartAsync();
  </code></pre>
  
  <p>In my server side i take this parameter from HttpContext:</p>
  
  <pre><code> public override async Task OnConnectedAsync()
          {
              var group = Context.GetHttpContext().Request.Query["token"];
  
              string value = !string.IsNullOrEmpty(group.ToString()) ? group.ToString() : "default";
  
              await Groups.AddToGroupAsync(Context.ConnectionId, value);
              await base.OnConnectedAsync();              
          }
  </code></pre>
  
  <p>but <code>GetHttpContext ().Request.Query["token"]</code> is null, because the group name receives "default" as indicated by the following code</p>
  
  <pre><code>string value = !string.IsNullOrEmpty(group.ToString()) ? group.ToString() : "default";
  </code></pre>
  
  <p>am I forgetting a step?
  I am using aspnetcore 2.1</p>