Question

I need to control the access to views based on users privilege levels (there are no roles, only privilege levels for CRUD operation levels assigned to users) in my MVC 4 application.

As an example; below the AuthorizeUser will be my custom attribute and I need to use it like this:

[AuthorizeUser(AccessLevels="Read Invoice, Update Invoice")]
public ActionResult UpdateInvoice(int invoiceId)
{
   // some code...
   return View();
}


[AuthorizeUser(AccessLevels="Create Invoice")]
public ActionResult CreateNewInvoice()
{
  // some code...
  return View();
}


[AuthorizeUser(AccessLevels="Delete Invoice")]
public ActionResult DeleteInvoice(int invoiceId)
{
  // some code...
  return View();
}

Is it possible to do it this way?

Answer 1

I could do this with a custom attribute as follows.

[AuthorizeUser(AccessLevel = "Create")]
public ActionResult CreateNewInvoice()
{
    //...
    return View();
}

Custom Attribute class as follows.

public class AuthorizeUserAttribute : AuthorizeAttribute
{
    // Custom property
    public string AccessLevel { get; set; }

    protected override bool AuthorizeCore(HttpContextBase httpContext)
    {
        var isAuthorized = base.AuthorizeCore(httpContext);
        if (!isAuthorized)
        {                
            return false;
        }

        string privilegeLevels = string.Join("", GetUserRights(httpContext.User.Identity.Name.ToString())); // Call another method to get rights of the user from DB

        return privilegeLevels.Contains(this.AccessLevel);           
    }
}

You can redirect an unauthorised user in your custom AuthorisationAttribute by overriding the HandleUnauthorizedRequest method:

protected override void HandleUnauthorizedRequest(AuthorizationContext filterContext)
{
    filterContext.Result = new RedirectToRouteResult(
                new RouteValueDictionary(
                    new
                        { 
                            controller = "Error", 
                            action = "Unauthorised" 
                        })
                );
}