services/api/lib/can_be_an_owner.rb

   1 # Protect
   2
   3 module CanBeAnOwner
   4
   5   def self.included(base)
   6     # Rails' "has_many" can prevent us from destroying the owner
   7     # record when other objects refer to it.
   8     ActiveRecord::Base.connection.tables.each do |t|
   9       next if t == base.table_name
  10       next if t == 'schema_migrations'
  11       klass = t.classify.constantize
  12       next unless klass and 'owner_uuid'.in?(klass.columns.collect(&:name))
  13       base.has_many(t.to_sym,
  14                     foreign_key: :owner_uuid,
  15                     primary_key: :uuid,
  16                     dependent: :restrict)
  17     end
  18     # We need custom protection for changing an owner's primary
  19     # key. (Apart from this restriction, admins are allowed to change
  20     # UUIDs.)
  21     base.validate :restrict_uuid_change_breaking_associations
  22   end
  23
  24   protected
  25
  26   def restrict_uuid_change_breaking_associations
  27     return true if new_record? or not uuid_changed?
  28
  29     # Check for objects that have my old uuid listed as their owner.
  30     self.class.reflect_on_all_associations(:has_many).each do |assoc|
  31       next unless assoc.foreign_key == :owner_uuid
  32       if assoc.klass.where(owner_uuid: uuid_was).any?
  33         errors.add(:uuid,
  34                    "cannot be changed on a #{self.class} that owns objects")
  35         return false
  36       end
  37     end
  38
  39     # if I owned myself before, I'll just continue to own myself with
  40     # my new uuid.
  41     if owner_uuid == uuid_was
  42       self.owner_uuid = uuid
  43     end
  44   end
  45
  46 end