Question

in my invite.rb model I have the following:

class Invite < ActiveRecord::Base
  before_create :assign_code
  validates_uniqueness_of :code, :case_sensitive => false, :message => "This invite code is taken!"

  protected

  # Create a safe random token and ensuring it's uniqueness for the model
  def assign_code
    begin
      code = SecureRandom.urlsafe_base64
    end while Invite.where(:code => code).exists?
    self.code = code
  end

Problem is in the logs I see the follow below. Why is rails doing a query for a code which is null, seems like a wasted query.

Invite Exists (0.5ms)  SELECT 1 AS one FROM "invites" WHERE "invites"."code" IS NULL LIMIT 1
Invite Exists (0.3ms)  SELECT 1 AS one FROM "invites" WHERE "invites"."code" = 'mTGCX0yCyTgplGfGQ5hGeA' LIMIT 1

Any ideas? Thanks

Answer 1

You probably want to use before_validation :assign_code instead, that way the code gets set before it’s validated.