ruby-on-rails – 在ActiveRecord中如何在before_save回调中使用

如果我创建一个新记录,如果我输入一个保存的摘要,如果我没有使用正文来生成摘要,这似乎工作正常.

但是,当我更新记录时,摘要总是被覆盖.从我的日志文件中我可以看到’generate_summary’被调用两次,第二次’changes’hash为空.

class Document << ActiveRecord::Base
  # Callbacks
  before_save  :generate_summary

private

  def generate_summary
    @counter ||= 1

    logger.debug '$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$'
    logger.debug @counter.to_s
    logger.debug 'changes: ' + self.changes.inspect
    self.summary = Sanitize.clean(self.body).to(255) if self.body && (!self.summary_changed? or self.summary.blank?)
    @counter = @counter + 1
end

登录更新：

$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$

1

更改：{“summary”=> [“asdasdasdasd”,“three.co.uk”]}

页面更新(0.7ms)更新文件SET meta_description =’three.co.uk’,summary =’three.co.uk’,updated_at =’2009-09-30 11:37:08’WHERE id = 77

SQL(0.6ms)COMMIT

SQL(0.1ms)BEGIN

$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$

2

变化： {}

页面更新(0.5ms)UPDATE文件设置meta_description =’asdasdasdasd’,summary =’asdasdasdasd’,updated_at =’2009-09-30 11:37:08’WHERE id = 77