Accessing Rails Form Errors in rails 2.x

Is there a way to access form errors in the controller? In the view I can access form errors using

from.error_messages

I want to list errors in a flash message before may layout header, how do I 开发者_运维技巧go about accessing those errors in the controller so I can assign them to a flash message?

---

@model_instance.errors.full_messages.to_sentence

---

You may find error_messages_for and similar methods to be more convenient way to display errors in another place. More details here:
http://guides.rubyonrails.org/activerecord_validations_callbacks.html#displaying-validation-errors-in-the-view

What you want well may be already supported, as it's often the case with rails.