All we know that Rails Admin give us capability to restrict records through authorization, I have made a heavy use this feature, but sometimes we need to restrict a few fields in a given model through roles or something else. How could we get it?

Let's suppose we have a field called product_type in Product model, in our rails_admin initializer file we would have something like that:

config.model Product do
  # ...
  create do
    field :name
    field :product_type do
      label 'Product Type'
    end
  end
end

This way, all users could be changing the product type, let's restrict this field now in order to just users with role master can be changing it:

config.model Product do
  # ...
  create do
    field :name
    field :product_type do
      label do
        if bindings[:view]._current_user.has_role? :master
          'Product Type'
        else
          false
        end
      end
      help false
      render do
        if bindings[:view]._current_user.has_role? :master
          bindings[:view].render :partial => "rails_admin/main/#{partial}", :locals => {:field => self, :form => bindings[:form] }
        else
          ''
        end
      end
    end
  end
end

In the render block is where the magic happens, if the condition is satisfied then we call the default behavior from Rails Admin that is here, otherwise we just return an empty string.

See you.