Should my MVC controller really know about JSON?

Question

The JsonResult class is a very useful way to return Json as an action to the client via AJAX.

public JsonResult JoinMailingList(string txtEmail)
{
        // ...         


        

Answer 1

I generally try not to worry about it. The Asp.Net MVC is enough of a separation of concerns to keep leakage to a minimum. You're right though; there is a bit of a hurdle when testing.

Here's a test helper I use, and it's worked well:

protected static Dictionary GetJsonProps(JsonResult result)
{
    var properties = new Dictionary();
    if (result != null && result.Data != null)
    {
        object o = result.Data;
        foreach (PropertyDescriptor prop in TypeDescriptor.GetProperties(o))
            properties.Add(prop.Name, prop.GetValue(o) as string);
    }
    return properties;
}

You can use the Request.IsAjaxRequest() extension method to return different ActionResult types:

if (this.Request != null && this.Request.IsAjaxRequest())
    return Json(new { Message = "Success" });
else
    return RedirectToAction("Some Action");

Note: you'll need that Request != null to not break your tests.