Get a string that represents a user's CanCan abilities

Question

I want to cache a Post view, but the view depends on the permissions of the current user (e.g., I only show the \"edit\" link if current_user.can?(:edit, @pos

Answer 1

EDIT: revised for CanCanCan

As of version 1.12 of CanCanCan (the community continuation of CanCan), Ability.new(user).permissions returns a hash with all permissions for the given user.

Previous answer (CanCan):

This might be a little complex...but here it goes..

If you pass the specified User into the Ability model required by CanCan, you can access the definition of that users role using instance_variable_get, and then break it down into whatever string values you want from there..

>> u=User.new(:role=>"admin")
>> a=Ability.new(u)
>> a.instance_variable_get("@rules").collect{ 
      |rule| rule.instance_variable_get("@actions").to_s
   }
=> ["read", "manage", "update"]

if you want to know the models in which those rules are inflicted upon, you can access the @subjects instance variable to get its name..

here is the model layout for Ability from which I worked with (pp)

Ability:0x5b41dba @rules=[
  #, 
  #, 
  #4}, 
    @match_all=false, 
    @block=nil, 
    @subjects=[
      User(role: string)]>
]