ActiveModel destroy after calling new

I'm working with a controller that follows the resource_controller principle explained here.

As you can see, I don't have full control on the (new, create etc...) all of them preload data, which means if I want to create a new entity let's say @user the following code has already been called @user = User.new.

The only way I can include some validation is through callbacks, but once the callback decides to cancel the new method, I always end 开发者_开发百科up with a Hash frozen error. In other words, I can't say @user = User.new @user.destroy

The only hack I was able to come up with was @user = User.new @user.save @user.destroy

Does anyone know a better way, which doesn't involve saving things to the database? And btw what is the difference between active record and active model?

---

How about checking if it's been saved before destroying it?

@user.destroy unless (@user.new_record?)