ruby - 一次定义类和实例方法 - Ruby

Question

我愿意:

module MyLog

  def log
    unless @log
      @log = Logger.new(log_path)
      @log.formatter =  proc do |severity, datetime, progname, msg|
        "#{datetime} #{msg}\n"
      end
    end
    @log
  end

end

像这样在其他类之间重用:

Class A
  def self.log_path; 'log/a.log' end
  def log_path; 'log/a.log' end
  include MyLog
  extend  MyLog

  def some_method
    log.debug 'some thing'
  end

  def self.some_class_method
    log.debug 'in a class method'
  end

end

有没有比A类开始的那四条线更短的路呢？

另一件事

我想批量登录:

def expire
  expired_ids = []
  failed_ids  = []

  all.each do |event|
    if event.expire # saves record
      expired_ids << event.id
    else
      failed_ids << event.id
    end
  end

  log.debug "These ids were expired: #{ expired_ids }"
  log.debug "These ids failed to expire: #{ failed_ids }"
end

有没有办法让我干净地做到这一点？将日志记录与方法逻辑分开？

Answer 1

这就是我最近在遇到像您这样的问题时一直在做的事情:

class A
  class << self
    include MyLog

    def log_path
      'log/a.log'
    end
  end

  delegate :log_path, :log, to: "self.class"
end

否则，选择最佳编程方法取决于您的情况、您将重用脚本的频率、在其生命周期内需要重构脚本的次数等等。但无论如何，请不要试图节省代码的行，尽量省去自己下次阅读代码时的麻烦。

关于你的第二个问题，你面临的主要困境是，是否值得你引入 Events 类:

class Events < Array
  def foobar
    each_with_object [[], []] do |event, (expired_ids, failed_ids)| 
      ( event.expire ? expired_ids : failed_ids ) << event.id
    end
  end
end

然后当时间到来时:

def expire
  expired_ids, failed_ids = Events[ all ].foobar
  log.debug "These ids were expired: #{ expired_ids }"
  log.debug "These ids failed to expire: #{ failed_ids }"
end