CanCanCan可以授权相关对象(CanCanCan authorize associated objects)

 我的Routes.rb： 
 
resources :users
resources :clients do
  resources :branches
end
 
 我在Ability.rb中有这个。 用户只能更新自己的客户。 
 
  can [:update], Client, :id => user.clients.pluck(:id)
 
 用户还应该能够：create，：update，：显示属于客户端的分支。 它可能看起来像这样： 
 
  can [:create, :update, :show], Branch, :client => { :id => user.clients.pluck(:id) }
 
 它适用于：update，：show，但不适用于：create。 这是因为new Branch在创建之前没有client_id。 我如何使其工作：创建？ 

My Routes.rb:
 
resources :users
resources :clients do
  resources :branches
end
 
I have this in Ability.rb. User can update only his own clients. 
 
  can [:update], Client, :id => user.clients.pluck(:id)
 
User should be also able to :create, :update, :show branches which belong to client. It might look somehting like this:
 
  can [:create, :update, :show], Branch, :client => { :id => user.clients.pluck(:id) }
 
It works for :update, :show, but not for :create. It's because new Branch doesn't have client_id before create. How do I make it work for :create?

原文：https://stackoverflow.com/questions/28624916