Trouble calling a ASP.NET MVC 4 WebApi from a Windows Store Application

Question

I've got the following code running in a Windows Store application that is supposed to call one of my WebApis:

using (var client = new HttpClient())
{
    var parms = new Dictionary<string, string>
        {
            {"vinNumber", vinNumber}, 
            {"pictureType", pictureType}, 
            {"blobUri", blobUri}
        };

    HttpResponseMessage response;

    using (HttpContent content = new FormUrlEncodedContent(parms))
    {
        const string url = "http://URL/api/vinbloburis";

        response = await client.PostAsync(url, content);
    }

    return response.StatusCode.ToString();
}

The WebApi code looks like this:

[HttpPost]
public HttpResponseMessage Post(string vinNumber, string pictureType, string blobUri)
{
    var vinEntity = new VinEntity
        {
            PartitionKey = vinNumber,
            RowKey = pictureType, 
            BlobUri = blobUri
        };

    _vinRepository.InsertOrUpdate(vinEntity);

    return new HttpResponseMessage { Content = new StringContent("Success"), StatusCode = HttpStatusCode.OK };
}

Using Fiddler, I've observed the following ... here's what the request looks like:

POST http://URL/api/vinbloburis HTTP/1.1
Content-Type: application/x-www-form-urlencoded
Host: URL
Content-Length: 113
Expect: 100-continue

vinNumber=vinNumber&pictureType=top&blobUri=https%3A%2F%2Fmystorage.blob.core.windows.net%2Fimages%2Fimage.png

But the response is an error with little/no information:

{"Message":"An error has occurred."}

I've even tried locally with the debugger attached to the WebApis and my Post method never catches.

Does anyone see something I've missed here? I feel like I'm looking right at it but not seeing it. I should add that I am able to call an HttpGet method while passing a parameter through the querystring. Right now the problem is only with this HttpPost.

Thanks!

UPDATE: Based on some good comments from folks I'm adding some more details.

I have the default routes configured for WebApis ...

public static void Register(HttpConfiguration config)
{
    config.Routes.MapHttpRoute(
        name: "DefaultApi",
        routeTemplate: "api/{controller}/{id}",
        defaults: new { id = RouteParameter.Optional }
    );
}

Consequently, I think /URL/api/vinbloburis should work. Additionally, as alluded above, I currently have this working with an HttpGet. Here's what's working in the Windows Store app to call the HttpGet WebApi ...

using (var client = new HttpClient())
{
    using (var response = await client.GetAsync(uri))
    {
        if (response.IsSuccessStatusCode)
        {
            var sasUrl = await response.Content.ReadAsStringAsync();
            sasUrl = sasUrl.Trim('"');

            return sasUrl;
        }
    }
}

... and it's calling the following WebApi ...

[HttpGet]
public HttpResponseMessage Get(string blobName)
{
    const string containerName = "images";
    const string containerPolicyName = "policyname";

    _helper.SetContainerPolicy(containerName, containerPolicyName);

    string sas = _helper.GenerateSharedAccessSignature(blobName, containerName, containerPolicyName);

    return new HttpResponseMessage
        {
            Content = new StringContent(sas),
            StatusCode = HttpStatusCode.OK
        };
}

I hope the additional information helps!

Answer 1

I copied your code, as is and I was getting a 404 error.

I changed the signature to

public HttpResponseMessage Post(FormDataCollection data)

and it worked.

You can also just do this,

public HttpResponseMessage Post(VinEntity vinEntity)

and the model binder will do the mapping work for you.

Rick Strahl has a post on the issue here http://www.west-wind.com/weblog/posts/2012/Sep/11/Passing-multiple-simple-POST-Values-to-ASPNET-Web-API