How to obtain connection ID of signalR client on the server side?

Question

I need to get the connection ID of a client. I know you can get it from the client side using $.connection.hub.id. What I need is to get in while in a web service I have which updates records in a database, in turn displaying the update on a web page. I am new to signalR and stackoverflow, so any advice would be appreciated. On my client web page I have this:

<script type="text/javascript">     $(function () {         // Declare a proxy to reference the hub.          var notify = $.connection.notificationHub;          // Create a function that the hub can call to broadcast messages.         notify.client.broadcastMessage = function (message) {             var encodedMsg = $('<div />').text(message).html();// Html encode display message.             $('#notificationMessageDisplay').append(encodedMsg);// Add the message to the page.         };//end broadcastMessage          // Start the connection.         $.connection.hub.start().done(function () {             $('#btnUpdate').click(function () {                 //call showNotification method on hub                 notify.server.showNotification($.connection.hub.id, "TEST status");             });         });       });//End Main function   </script> 

everything works up until I want to update the page using signalR. The show notification function in my hub is this:

//hub function public void showNotification(string connectionId, string newStatus){                    IHubContext context = GlobalHost.ConnectionManager.GetHubContext<notificationHub>();     string connection = "Your connection ID is : " + connectionId;//display for testing     string statusUpdate = "The current status of your request is: " + newStatus;//to be displayed     //for testing, you can display the connectionId in the broadcast message     context.Clients.Client(connectionId).broadcastMessage(connection + " " + statusUpdate); }//end show notification 

how can I send the connectionid to my web service?

Hopefully I'm not trying to do something impossible. Thanks in advance.

Answer 1

When a client invokes a function on the server side you can retrieve their connection ID via Context.ConnectionId. Now, if you'd like to access that connection Id via a mechanism outside of a hub, you could:

1. Just have the Hub invoke your external method passing in the connection id.
2. Manage a list of connected clients aka like public static ConcurrentDictionary<string, MyUserType>... by adding to the dictionary in OnConnected and removing from it in OnDisconnected. Once you have your list of users you can then query it via your external mechanism.

Ex 1:

public class MyHub : Hub {     public void AHubMethod(string message)     {         MyExternalSingleton.InvokeAMethod(Context.ConnectionId); // Send the current clients connection id to your external service     } } 

Ex 2:

public class MyHub : Hub {     public static ConcurrentDictionary<string, MyUserType> MyUsers = new ConcurrentDictionary<string, MyUserType>();      public override Task OnConnected()     {         MyUsers.TryAdd(Context.ConnectionId, new MyUserType() { ConnectionId = Context.ConnectionId });         return base.OnConnected();     }      public override Task OnDisconnected(bool stopCalled)     {         MyUserType garbage;          MyUsers.TryRemove(Context.ConnectionId, out garbage);          return base.OnDisconnected(stopCalled);     }      public void PushData(){         //Values is copy-on-read but Clients.Clients expects IList, hence ToList()         Clients.Clients(MyUsers.Keys.ToList()).ClientBoundEvent(data);     } }  public class MyUserType {     public string ConnectionId { get; set; }     // Can have whatever you want here }  // Your external procedure then has access to all users via MyHub.MyUsers 

Hope this helps!