PollingDuplexHttpBinding and app pool recycles

Question

I use a PollingDuplexHttpBinding so that clients can exchange messages in my application. Clients are registers via a RegisterClient() method that adds them to a static dictionary for future use.

The code looks like this:

[ServiceContract(Namespace = "...", CallbackContract = typeof(MyServiceCallback))]
public class MyService
{
    public static Dictionary<string, MyServiceCallback> Clients =
        new Dictionary<string, MyServiceCallback>();

    [OperationContract]
    public void RegisterClient(string name)
    {
        Clients[name] =
            OperationContext.Current.GetCallbackChannel<MyServiceCallback>();
    }

    public static void SendMessage(string name, string message)
    {
        Clients[name].SendMessage(message);
    }
}

[ServiceContract]
public interface MyServiceCallback
{
    [OperationContract(IsOneWay = true)]
    void SendMessage(string message);
}

Everything works well except when the application pool gets recycled.

Of course I realize that the static stuff is not ideal in that regard.

Where would be a good place to save my client references so that they survive an app pool recyle?

Answer 1

I don't think you can make themn survive an app pool recycle since for that you would need to persist and recreate the Channels...

A better approach would be IMHO to host your WCF service in a Windows Service (no app pool recycling) for this kind of stuff...