ASP.NET WebAPI fails from MVC4 controller - asp.net-mvc-4

Question

I'm new to ASP.NET Web API and I'm struggling with a very strange problem.
I have some code which calls a RESTful service and it executes fine from a console project, but I can't get it to run from an MVC4 project running under .NET 4.0
The code to call the service is very simple:
internal string Test()
{
using (var client = new HttpClient())
{
client.BaseAddress = new Uri("https://testserver");
var task = client.GetAsync("/someUri")
var response = task.Result;
response.EnsureSuccessStatusCode();
return response.Content.ReadAsStringAsync().Result;
}
}
As mentioned, called from a console project it works as expected and I get a response in milliseconds, however if I call the method from an action in my MVC4 controller after a few seconds I get a message stating that:
"A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to repond".
Weirdly, when debugging the MVC4 version, the task status always shows as WaitingForActivation.
Running fiddler doesn't show any request being made from the MVC4 version, but again does for the Console version.
After a fairly serious bit of googling I can't find anyone else who seems to have had this problem, so I'm guessing that I've fundamentally misunderstood something, but at the moment I'm not sure what!
Updated 16:55 BST, 11/09/2012
To make things even weirder, I've just created a new MVC4 site and I can call the method without any problems! I'm now trying to compare the sites, however one was an existing site that was upgraded to MVC4 and the other is a new blank site, so spotting the relevant difference could be tricky.
Updated 16:44 BST, 14/09/2012
This is now looking like some infrastructure / networking issue.
I upgraded the project to VS2012 with .NET 4.5 so that I could use async/await to try the suggested implementations to avoid a deadlock. This didn't change anything so I went back to square 1.
I created a new solution with a new MVC4 project, a new services library and a unit test project to run the service library outside of MVC.
In the service library I created one method to call a public "what's my IP" service, and another to call a company service that's exposed publicly but only responds properly to company IP addresses.
For some background, I connect in to the company LAN via a VPN.
When disconnected from the VPN, in both unit tests and MVC, the IP service responds HTTP 200, the company service responds HTTP 404 as expected.
When connected to the VPN, unit tests both respond HTTP 200, MVC both timeout.
Next I ran MS Soap Tool locally and used that to proxy calls to the company services. All calls (whether from unit tests or MVC) show a request and response, but the unit test registers the response whilst the MVC controller does not.
My only other thought is that it could be something to do with the size of the reply? All the "successes" have very small replies other than the unit test calling the company service?

Answer 1

The Microsoft recommended way to upgrade an MVC3 to MVC4 site is to start with a completely new MVC4 site a migrate your views, controllers & code over. So I think that your upgrade steps may be part of your issue, since you were able to get it to work in the new MVC4 site you created. If you need to manually upgrade your existing site, I would follow the steps outlined in Upgrading ASP.NET MVC 3 Project to ASP.NET MVC 4