SignalR - How can I call Hub Method on server from server

Question

I have SignalR working between an ASP.NET (formerly MVC) server and a Windows Service client in the sense that the client can call methods on the Server Hub and then display to Browsers. The Hub code is:

  public class AlphaHub : Hub
        {
            public void Hello(string message)
            {
                // We got the string from the Windows Service 
                // using SignalR. Now need to send to the clients
                Clients.All.addNewMessageToPage(message);

                // Call Windows Service
                string message1 = System.Environment.MachineName;
                Clients.All.Notify(message1);


            }
     public void CallForReport(string reportName)
     {
          Clients.All.CallForReport(reportName);
     }

On the client (Windows Service) I have been calling methods on the Hub:

var hubConnection = new HubConnection("http://localhost/AlphaFrontEndService/signalr",
                    useDefaultUrl: false);
                IHubProxy alphaProxy = hubConnection.CreateHubProxy("AlphaHub");

                await hubConnection.Start();
                string cid = hubConnection.ConnectionId.ToString();
                eventLog1.WriteEntry("ConnectionID: " + cid);
                // Invoke method on hub

                await alphaProxy.Invoke("Hello", "Message from Service - ConnectionID: " + cid + " - " + System.Environment.MachineName.ToString() + " " + DateTime.Now.ToString());

Now, suppose this scenario: The user wll go a particular ASP.NET form like Insured.aspx on the server. In that I want to call CallForReport and then call this method on the client:

 public void CallFromReport(string reportName)
        {
            eventLog1.WriteEntry(reportName);
        }

How do I get a connection to my own Hub on the server and call the method. I tried the following things from Insured.aspx:

 protected void Page_Load(object sender, EventArgs e)
        {
            // Hubs.AlphaHub.CallForReport("Insured Report");
            // IHubContext hubContext = GlobalHost.ConnectionManager.GetHubContext<AlphaHub>();
            // hubContext.Clients.All.CallForReport("Insured Report");
        }

Answer 1

I don't see any calls to IHubProxy.On. That is the method you need to hook up your CallFromReport method to your AlphaHub IHubProxy on the client.

 var hubConnection = new HubConnection("http://localhost/AlphaFrontEndService/");
 IHubProxy alphaProxy = hubConnection.CreateHubProxy("AlphaHub");

 alphaProxy.On<string>("CallForReport", CallFromReport);

 await hubConnection.Start();

 // ...

Once you have that, the last two lines you have commented in Page_Load should work.

protected void Page_Load(object sender, EventArgs e)
{
    IHubContext hubContext = GlobalHost.ConnectionManager.GetHubContext<AlphaHub>();
    hubContext.Clients.All.CallForReport("Insured Report");
}