Rails - How to declare attr_accessible for multiple roles without duplication - ruby-on-rails

Question

Is there a way to declare attr_accessible for multiple roles without a ton of duplication?
If I have several user roles, and each role is allowed to edit a different subset of attributes, here's what my attr_accessible declaration looks like:
attr_accessible :first_name, :last_name, :active, :as => :admin
attr_accessible :first_name, :last_name, :as => :manager
attr_accessible :first_name, :last_name, :as => :guest
I'd like to either
A) define an array of accessible attributes that can be shared among
different roles or
B) define an array of roles than can access the same
attributes
Is this possible?

Answer 1

I just spent a long time trying to figure out the best way to do this. It seemed strange that the rails folk would expect you to duplicate a whole bunch of code!
After some digging around in the rails source, it turns out you can simply pass an array to assign attributes to multiple roles at once (:default being the default Active Record role)
attr_accessible :name, :email, :as => [ :default, :admin ]
attr_accessible :featured, :as => :admin
No messy ruby arrays in your model!

Answer 2

All ruby code is still just ruby code... and is thus infinitely hackable. eg
ROLES = [:admin, :manager, :support, :user, :guest]
ACTIVE_ROLES = [:admin, :support]
ROLES.each do |role|
fields = [:first_name, :last_name]
fields += [:active] if ACTIVE_ROLES.include?(role)
attr_accessible *fields, :as => role
end

Answer 3

Did you try something like:
COMMON_FIELDS = [:first_name, :last_name]
attr_accessible COMMON_FIELDS | [:active, :as => :admin]
attr_accessible COMMON_FIELDS | [:as => :manager]
attr_accessible COMMON_FIELDS | [:as => :guest]
Another possible way (untested):
attr_accessible :first_name, :last_name
ADMIN_ACCESSIBLE = [:active]
MANAGER_ACCESSIBLE = []
GUEST_ACCESSIBLE = []
protected
def mass_assignment_authorizer
if role == :all
self.class.protected_attributes
else
super + (eval("#{role}_accessible".upcase) || [])
end
end