manage cart errors from module

[Franck K.]

Hello.

 

I have already override the preProcess method from the OrderController class so I can add new conditions to allow the order.

 

I'd like to add these conditions from a module. I think about a method running when the user is processing the order and blocking him if it does not respect some conditions (for exemple he's not a part of a specific group).

 

Do I have to use a specific hook ? I think so but can I access the errors[] array of the OrderController class from my module ?

 

Yes, I am pretty lost =).

 

I hope I have been clear.

 

Thank you very much for the help.