控制器动作中的异步Web响应

Question

I have an MVC controller. In that controller I reference a WCF service that accesses a 3rd party request (through webrequest) which returns information which is then saved in the WCf service (very specifically, we're collection data about visits and saving them into a database so that we can target our page organization better).

The TL;DR is like this:

 private ActionResult CollectTrackingData(string campaign = "none")
    {
        VanityURLService.VanityURLConnector connector = new VanityURLService.VanityURLConnector();
        connector.SaveTrackingData(Request, campaign); 
        return View(someVarView);
    }

The SaveTrackingData does a bunch of stuff until it calls this method (edited to protect the not-so-innocent):

 private string TranslateGeolocation(string ipAddress)
    {
        WebRequest pageRequest = System.Net.WebRequest.Create("http://blahblah.com");
        WebResponse resp = pageRequest.GetResponse();

        System.IO.StreamReader sr = new System.IO.StreamReader(resp.GetResponseStream());
        string reqResp = sr.ReadToEnd().Trim();
        return reqResp.ToString();
    }

The part that is likely to cause problems is the WebResponse resp = pageRequest.GetResponse(); but I can't help thinking that the best way to do that is to make the call that cascades the entire process asynchoronous (that would be the controller code: connector.SaveTrackingData(Request, campaign);

But when I try to make the call async, it whines at me about a few things until, after much tweaking, it demands that I have it return a return type and then still doesn't work because I supposedly can't make that asynchronous at that stage of the page life cycle (which it then offers aspx code which is useless since I'm running with a Razor engine).

This all seems like it's being way more difficult than it needs to be. I feel like I should be able to make the CollectTrackingData() call async but it doesn't like that.

Can someone point me in the right direction?

Answer 1

Just change your action method to return Task<ActionResult> .

Everything will then work fine.

Answer 2

To convert your method to async, the correct method signature is:

private Task<string> TranslateGeolocation(string ipAddress)

Then to call it:

string str = await TranslateGeolocation(ipAddress);

The await keyword will unwrap the string from the Task<> for you.

If you were to want to convert a method that would normally not return a value, ie,

private void DoSomething()

the asynchronous signature would be:

private Task DoSomething()