ASP.NET MVC request intercept and get model value

Question

I have lots of controllers, which return data, based on parameters.

But users can fake the parameters they send to server, so I would like to intercept all requests, and if some parameter that come back with model is not valid, give warning/error.

the example header of controller is this

[Intercept<CarModel>] <-- I want something like this, <CarModel> because the interceptor knows what type to cast the model when intercepted
public object Cards(CarModel model) {

I would like to create this kind of attribute, that intercepts the controller, checks if model is valid.

How could I do this? I googled about it, but not found anything like this.

Answer 1

Just put your validation code in the action. Better yet, inherit from an IValidatable interface and implement HasPropertiesValid() on all your models. Then you just call model.HasPropertiesValid(); at the beginning of your action.

Validatable interface

interface IValidatable {
    bool IsPropertiesValid();
}

A model example

public class CarModel : IValidatable {
    public string ModelName {get;set;}
    public string ManufacturerName {get;set;}
    public bool IsPropertiesValid() {
        if(ManufacturerName == "Toyota") { 
            if(ModelName == "Prius") return true;
        }
        return false;
    }
}

Controller

public ActionResult ToyotaCar(CarModel model){
    if(!model.IsPropertiesValid()) return RedirectToAction("QuitMessingAround","CaughtYou");
}