ASP.NET MVC 3 Redirect Requests to Root Page

When a PJAX request is sent, it is always supposed to include this header in the HTTP Request:

X-PJAX: true

You can redirect the different requests by adding a custom ActionMethodSelectorAttribute that checks if the X-PJAX header is present.

Add this custom Attribute class to your solution:

public class AcceptHeaderAttribute : ActionMethodSelectorAttribute
{
    public string HeaderName { get; set; }

    public string HeaderValue { get; set; }

    public AcceptHeaderAttribute(string headerName, string headerValue = null)
    {
        if (String.IsNullOrWhiteSpace(headerName))
            throw new ArgumentNullException("headerName");

        HeaderName = headerName;
        HeaderValue = headerValue;
    }

    public override bool IsValidForRequest(ControllerContext controllerContext, System.Reflection.MethodInfo methodInfo)
    {
        if (controllerContext == null)
            throw new ArgumentNullException("controllerContext");

        var incomingHeader = controllerContext.HttpContext.Request.Headers[HeaderName];

        var headerExists = String.IsNullOrWhiteSpace(incomingHeader);

        // NOTE: can optionally change this to Contains, or add a parameter for that.
        var valueCorrect = String.Equals(incomingHeader, HeaderValue, StringComparison.OrdinalIgnoreCase);

        return (String.IsNullOrWhiteSpace(HeaderValue)
            ? headerExists
            : valueCorrect);
    }
}

You can then set different Action for PJAX requests versus direct user requests:

[AcceptHeader("X-PJAX", "true")]
public ActionResult About(string myInput)
{
    ViewBag.Test = "This is a PJAX request";

    return View();
}

public ActionResult About()
{
    ViewBag.Test = "This is a normal request";

    return View();

    // or redirect them to root page
    return RedirectToAction("Index");
}

If you only care to check that the Header exists in the HTTP Request, and don't care that the value is correct, you can simplify the usage to just:

[AcceptHeader("X-PJAX")]