UriPathExtensionMapping to control response format in WebAPI

I am having a problem running UriPathExtensionMapping in ASP.NET WebAPI. My setup is like this:

My routes:

            config.Routes.MapHttpRoute(
                name: "Api UriPathExtension",
                routeTemplate: "api/{controller}.{extension}/{id}",
                defaults: new { id = RouteParameter.Optional }
            );

            config.Routes.MapHttpRoute(
               name: "Api UriPathExtension ID",
                routeTemplate: "api/{controller}/{id}.{extension}",
                defaults: new { id = RouteParameter.Optional }
            );

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

      

        
        
        
      

    

My global ASAX file:

    AreaRegistration.RegisterAllAreas();

    WebApiConfig.Register(GlobalConfiguration.Configuration);
    FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
    RouteConfig.RegisterRoutes(RouteTable.Routes);
    BundleConfig.RegisterBundles(BundleTable.Bundles);

      

        
        
        
      

    

My controller:

public IEnumerable<string> Get()
{
    return new string[] { "Box", "Rectangle" };
}

// GET /api/values/5
public string Get(int id)
{
    return "Box";
}

// POST /api/values
public void Post(string value)
{
}

// PUT /api/values/5
public void Put(int id, string value)
{
}

// DELETE /api/values/5
public void Delete(int id)
{
}

      

        
        
        
      

    

When making requests using curl, JSON is the default response, even when I explicitly request XML, I still get JSON:

curl http://localhost/eco/api/products/5.xml

      

        
        
        
      

    

Return:

"http://www.google.com"

      

        
        
        
      

    

Can anyone see the problem with my setup?

The following code displays the extensions in the Global.asax file after the routes have been configured:

    GlobalConfiguration.Configuration.Formatters.JsonFormatter.
        MediaTypeMappings.Add(
            new UriPathExtensionMapping(
                "json", "application/json"
        )
    );

    GlobalConfiguration.Configuration.Formatters.XmlFormatter.
        MediaTypeMappings.Add(
            new UriPathExtensionMapping(
                "xml", "application/xml"
        )
    );