在后台运行异步操作方法

Question

Is there any way to call async action method in standard action method and not wait for the async method execution (keeping the same Request object)?

public class StandardController : Controller
{
    public ActionResult Save()
    {
        // call Background.Save, do not wait for it and go to the next line

        return View();
    }
}

public class BackgroundController : AsyncController
{
    public void SaveAsync()
    {
        // background work
    }
}

I've tried to use Task class to do the backround work, but when I was starting the task and the action method has returned the View, the Request was killed and my DependencyResolver instance was erased, so the background task started to throw exceptions.

The first idea was to execute the Standard.Save (without calling the background task) and return the View in which the Background.Save method could be called in ajax. So in other words: call the another request to the async controller, to start the background task.

The main problem is how to call the async method keeping the authorization information (in cookies) and dependency resolver (in my case: autofac).

Answer 1

You can run some async method in sync code:

public class StandardController : Controller
{
    public ActionResult Save()
    {
        //code...
        YourMethod();
        //code...
        return View();
    }
    public async void YourMethod()
    {
      await Task.Run(()=>{
      //your async code...
      });
    }
}

YourMethod() will be going before and after Save() is fully performed.

Answer 2

For me this is working great:

    public class PartnerController : Controller
    {
    public ActionResult Registration()
    {
        var model = new PartnerAdditional();
        model.ValidFrom = DateTime.Today;
        new Action<System.Web.HttpRequestBase>(MyAsync).BeginInvoke(this.HttpContext.Request, null, null);
        return View(model);
    }

    private void MyAsync(System.Web.HttpRequestBase req)
    {
        System.Threading.Thread.Sleep(5000);
        foreach (var item in req.Cookies)
        {
            System.Diagnostics.Debug.WriteLine(item);
        }
    }
}

The Page is posted back and aroud 10 seconds later Async appears in my Debug Output. Not sure how this would work with Cookies/Authentication infos but in doubt you can pass the values to the method.

Hope it helps.