Question

I currently have a MVC 3 Web Application with around 50 Views.

Is it somehow possible to provide some kind of API next to my Views so everything still works fine and dandy?

My kinda perfect world idea:

Server is running and every request gets to its view. The user can decide in his get request if he wants the raw data in lets say JSON. Additional to the raw data also the Structure/Names of the Viewmodel will be parsed so the Modelbinder can do his stuff.

or another approach might be to somehow deactivate my Views to have only the API available (again with raw data and structure).

Is this even possible (the modelbinder is kinda a big concern) and maybe even without much effort/trouble to do?

Answer 1

If you don’t want to do everything all over again with WebAPI, you can implement some ActionFilterAttribute to change the ActionResult based on some querystring f.i.
Something like this:

public class ResultSwitcherAttribute: ActionFilterAttribute
{
    public override void OnActionExecuted(ActionExecutedContext filterContext)
    {
        if (filterContext.HttpContext.Request["data"] != null && filterContext.HttpContext.Request["data"] == "json")
        {
            filterContext.Result = new JsonResult
                {
                    Data = (filterContext.Result as ViewResult).Model,
                    JsonRequestBehavior = JsonRequestBehavior.AllowGet
                };
        }
    }
}

Then, you’ll register that either in application_start or per controller/action like this:

[ResultSwitcherAttribute]
public class HomeController : Controller
{
    public ActionResult Index()
    {

        return View(new TestModel()
            {
                Web = "http://www.mywebpage.com", Name = "Yngve"
            });
    }
}

When you now access your url with ?data=json you’ll get a JSON-representation of the Model, instead of the view.

EDIT: Code sample updated