# Validation in a model that is not to be saved **URL:** \ **Category:** Rails\ **Created:** [December 20, 2006, 4:51pm UTC](https://www.ruby-forum.com/t/validation-in-a-model-that-is-not-to-be-saved/79906 "2006-12-20T16:51:11Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Jason1706](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e99b99/32.png) [@Jason1706](https://www.ruby-forum.com/u/Jason1706)\ **Post date:** [December 20, 2006, 4:51pm UTC](https://www.ruby-forum.com/t/validation-in-a-model-that-is-not-to-be-saved/79906/1 "2006-12-20T16:51:11Z")
Hi group, I built an input form that’s spread over multiple pages. I store the already given data (that match my models and my tables) in a cart-like object. That works so far. But since I dont save the data, when the user inputs it, validations don’t work. They may work on my last (submit) page, but that too late. Any way to make validations work even if they don’t pass the model? Thx in advance Jason ---
**Author:** ![Jason1706](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e99b99/32.png) [@Jason1706](https://www.ruby-forum.com/u/Jason1706)\ **Post date:** [December 20, 2006, 5:01pm UTC](https://www.ruby-forum.com/t/validation-in-a-model-that-is-not-to-be-saved/79906/2 "2006-12-20T17:01:15Z")
Hello Jason, 2006/12/20, Jason1706 [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid): > Any way to make validations work even if they don’t pass the model? If you have real ActiveRecord objects, you can call #valid? [http://api.rubyonrails.com/classes/ActiveRecord/Validations.html#M000800](http://api.rubyonrails.com/classes/ActiveRecord/Validations.html#M000800) ## Hope that helps ! François Beausoleil [http://blog.teksol.info/](http://blog.teksol.info/) [http://piston.rubyforge.org/](http://piston.rubyforge.org/) ---
**Author:** ![Jason1706](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e99b99/32.png) [@Jason1706](https://www.ruby-forum.com/u/Jason1706)\ **Post date:** [December 20, 2006, 5:03pm UTC](https://www.ruby-forum.com/t/validation-in-a-model-that-is-not-to-be-saved/79906/3 "2006-12-20T17:03:18Z")
I think you need to get the attributes of the object assigned like @object = Model.new(session[:cart]) @object.additional\_attribute = value @object.additional\_attribute = value if @object.valid? … end I _think_ something like that will work. Adam ---
**Author:** ![Jason1706](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e99b99/32.png) [@Jason1706](https://www.ruby-forum.com/u/Jason1706)\ **Post date:** [December 20, 2006, 8:15pm UTC](https://www.ruby-forum.com/t/validation-in-a-model-that-is-not-to-be-saved/79906/4 "2006-12-20T20:15:25Z")
Hi François, thx for your hint. So far, I was able to add basic validation to my model like that def validate errors.add\_on\_empty %w{ title description } end And in my controller where I temporarily store that object in my virtual cart I can probe on validity like that : def create @product = Product.new(params[:product]) if @product.valid? if @cart = find\_cart @cart.add\_product(@product) redirect\_to(:action =\> ‘display\_cart’) else render :action =\> ‘new’ end else redirect\_to(:action =\> ‘new’) end end But that great validation features for forms are still closed for me at that point. Anything I dont see? This way, I’d to to all that by hand … and I’m a lazy typist 🙂 Cheers Jason ---
**Author:** ![Jason1706](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e99b99/32.png) [@Jason1706](https://www.ruby-forum.com/u/Jason1706)\ **Post date:** [December 23, 2006, 8:24am UTC](https://www.ruby-forum.com/t/validation-in-a-model-that-is-not-to-be-saved/79906/5 "2006-12-23T08:24:30Z")
this will be your cup of tea: [http://www.realityforge.org/articles/2005/12/02/validations-for-non-activerecord-model-objects](http://www.realityforge.org/articles/2005/12/02/validations-for-non-activerecord-model-objects) ---
**Author:** ![Jason1706](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e99b99/32.png) [@Jason1706](https://www.ruby-forum.com/u/Jason1706)\ **Post date:** [December 23, 2006, 8:43am UTC](https://www.ruby-forum.com/t/validation-in-a-model-that-is-not-to-be-saved/79906/6 "2006-12-23T08:43:14Z")
I think the question Jason is asking is how does he validate the individual fields even though the model isn’t fully baked (because of the multi-page form). Is that correct? Validating for presence would be difficult in this situation because you have maybe three items that need to be present on the first page, two on the second, and two on the last. But the model instance won’t validate unless they’re all there. Here’s an idea. What if you store a ‘step’ attribute in the model, and only validate if you have reached the proper step? So the controller sets the step attribute to ‘2’ after step 2 and then you put in the model: validates\_presence\_of :foo, :if =\> Proc.new { |model| !model.step \>= 2 } Validating format would be similar. You can say something like: validates\_length\_of :foo, :within =\> 5…10, :if =\> Proc.new { |model| !model.foo.blank? } That way the validation won’t fire unless the field has data. Does that help? ---
**Author:** ![Jason1706](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e99b99/32.png) [@Jason1706](https://www.ruby-forum.com/u/Jason1706)\ **Post date:** [December 23, 2006, 8:46am UTC](https://www.ruby-forum.com/t/validation-in-a-model-that-is-not-to-be-saved/79906/7 "2006-12-23T08:46:46Z")
Adam B. wrote: > validates\_presence\_of :foo, :if =\> Proc.new { |model| !model.step \>= 2 } Whoops. No negation needed there. Should read: validates\_presence\_of :foo, :if =\> Proc.new { |model| model.step \>= 2 } And where I said ‘model’ I was being generic. To be consistent with your previous example, ‘model’ should be ‘product’ I guess: class Product validates\_presence\_of :foo, :if =\> Proc.new { |p| p.step \>= 2 } validates\_length\_of :foo, :within =\> 5…10, :if =\> Proc.new { |p| !p.foo.blank? } end /afb