ChatController.cs - An Async Chat Controller for MVC 3

ChatController.cs

using System.Web.MVC

public class ChatController : AsyncController
{
    [AsyncTimeout(ChatServer.MaxWaitSeconds * 1002)]
    public void IndexAsync()
    {
        AsyncManager.OutstandingOperations.Increment();

        ChatServer.CheckForMessagesAsync(msgs =>
        {
            AsyncManager.Parameters["response"] = new ChatResponse
            {
                messages = msgs
            };
            AsyncManager.OutstandingOperations.Decrement();
        });
    }

    public ActionResult IndexCompleted(ChatResponse response)
    {
        return Json(response);
    }

    [HttpPost]
    public ActionResult New(string user, string msg)
    {
        ChatServer.AddMessage(user, msg);
        return Json(new
            {
                d = 1
            });
    }
}