services/api/lib/has_uuid.rb

   1 module HasUuid
   2
   3   UUID_REGEX = /^[0-9a-z]{5}-([0-9a-z]{5})-[0-9a-z]{15}$/
   4
   5   def self.included(base)
   6     base.extend(ClassMethods)
   7     base.validate :validate_uuid
   8     base.before_create :assign_uuid
   9     base.before_destroy :destroy_permission_links
  10     base.has_many :links_via_head, class_name: 'Link', foreign_key: :head_uuid, primary_key: :uuid, conditions: "not (link_class = 'permission')", dependent: :restrict
  11     base.has_many :links_via_tail, class_name: 'Link', foreign_key: :tail_uuid, primary_key: :uuid, conditions: "not (link_class = 'permission')", dependent: :restrict
  12   end
  13
  14   module ClassMethods
  15     def uuid_prefix
  16       Digest::MD5.hexdigest(self.to_s).to_i(16).to_s(36)[-5..-1]
  17     end
  18     def generate_uuid
  19       [Server::Application.config.uuid_prefix,
  20        self.uuid_prefix,
  21        rand(2**256).to_s(36)[-15..-1]].
  22         join '-'
  23     end
  24   end
  25
  26   protected
  27
  28   def respond_to_uuid?
  29     self.respond_to? :uuid
  30   end
  31
  32   def validate_uuid
  33     if self.respond_to_uuid? and self.uuid_changed?
  34       if current_user.andand.is_admin and self.uuid.is_a?(String)
  35         if (re = self.uuid.match HasUuid::UUID_REGEX)
  36           if re[1] == self.class.uuid_prefix
  37             return true
  38           else
  39             self.errors.add(:uuid, "type field is '#{re[1]}', expected '#{self.class.uuid_prefix}'")
  40             return false
  41           end
  42         else
  43           self.errors.add(:uuid, "not a valid Arvados uuid '#{self.uuid}'")
  44           return false
  45         end
  46       else
  47         if self.new_record?
  48           self.errors.add(:uuid, "assignment not permitted")
  49         else
  50           self.errors.add(:uuid, "change not permitted")
  51         end
  52         return false
  53       end
  54     else
  55       return true
  56     end
  57   end
  58
  59   def assign_uuid
  60     if self.respond_to_uuid? and self.uuid.nil? or self.uuid.empty?
  61       self.uuid = self.class.generate_uuid
  62     end
  63     true
  64   end
  65
  66   def destroy_permission_links
  67     if uuid
  68       Link.destroy_all(['link_class=? and (head_uuid=? or tail_uuid=?)',
  69                         'permission', uuid, uuid])
  70     end
  71   end
  72 end