services/api/lib/has_uuid.rb

   1 # Copyright (C) The Arvados Authors. All rights reserved.
   2 #
   3 # SPDX-License-Identifier: AGPL-3.0
   4
   5 module HasUuid
   6
   7   UUID_REGEX = /^[0-9a-z]{5}-([0-9a-z]{5})-[0-9a-z]{15}$/
   8
   9   def self.included(base)
  10     base.extend(ClassMethods)
  11     base.validate :validate_uuid
  12     base.before_create :assign_uuid
  13     base.before_destroy :destroy_permission_links
  14     base.has_many(:links_via_head,
  15                   -> { where("not (link_class = 'permission')") },
  16                   class_name: 'Link',
  17                   foreign_key: :head_uuid,
  18                   primary_key: :uuid,
  19                   dependent: :destroy)
  20     base.has_many(:links_via_tail,
  21                   -> { where("not (link_class = 'permission')") },
  22                   class_name: 'Link',
  23                   foreign_key: :tail_uuid,
  24                   primary_key: :uuid,
  25                   dependent: :destroy)
  26   end
  27
  28   module ClassMethods
  29     def uuid_prefix
  30       Digest::MD5.hexdigest(self.to_s).to_i(16).to_s(36)[-5..-1]
  31     end
  32     def generate_uuid
  33       [Server::Application.config.uuid_prefix,
  34        self.uuid_prefix,
  35        rand(2**256).to_s(36)[-15..-1]].
  36         join '-'
  37     end
  38   end
  39
  40   protected
  41
  42   def respond_to_uuid?
  43     self.respond_to? :uuid
  44   end
  45
  46   def validate_uuid
  47     if self.respond_to_uuid? and self.uuid_changed?
  48       if current_user.andand.is_admin and self.uuid.is_a?(String)
  49         if (re = self.uuid.match HasUuid::UUID_REGEX)
  50           if re[1] == self.class.uuid_prefix
  51             return true
  52           else
  53             self.errors.add(:uuid, "type field is '#{re[1]}', expected '#{self.class.uuid_prefix}'")
  54             return false
  55           end
  56         else
  57           self.errors.add(:uuid, "not a valid Arvados uuid '#{self.uuid}'")
  58           return false
  59         end
  60       else
  61         if self.new_record?
  62           self.errors.add(:uuid, "assignment not permitted")
  63         else
  64           self.errors.add(:uuid, "change not permitted")
  65         end
  66         return false
  67       end
  68     else
  69       return true
  70     end
  71   end
  72
  73   def assign_uuid
  74     if self.respond_to_uuid? and self.uuid.nil? or self.uuid.empty?
  75       self.uuid = self.class.generate_uuid
  76     end
  77     true
  78   end
  79
  80   def destroy_permission_links
  81     if uuid
  82       Link.destroy_all(['link_class=? and (head_uuid=? or tail_uuid=?)',
  83                         'permission', uuid, uuid])
  84     end
  85   end
  86 end