ruby-on-rails - 从 Rails 中保存的失败模型中恢复的最佳方法

Question

我有一些代码可以从 twitter API 获取一些推文:

initial_tweets = get_tweets_in_time_range self.name, (Time.now-1.weeks), Time.now 

initial_tweets.each do |tweet|
    new_tweet = Tweet.new

    new_tweet.favorite_count = tweet.favorite_count 
    new_tweet.filter_level = tweet.filter_level 
    new_tweet.retweet_count = tweet.retweet_count 
    new_tweet.text = tweet.text 
    new_tweet.tweeted_at = tweet.created_at 

    new_tweet.created_at = DateTime.strptime tweet.created_at.to_s, '%Y-%m-%d %H:%M:%S %z' 

    new_tweet.save 
    # What happens on a failed save
end

如果保存失败，正确的回退是什么？正如评论所在的位置所指出的那样。谢谢你的帮助。

Answer 1

save只返回true或false，可以使用save!，如果记录无效会抛出异常。如果引发异常，您可以捕获它。

begin
  ....
  new_tweet.save!
rescue exception => e
  puts e.inspect
  #you can continue the loop or exit
end

正如@Stefan 所说，您可以将代码包装在一个事务中，如果一条记录保存失败，所有保存的记录都会回滚。我不建议您这样做，除非您真的希望每条记录都成功保存。

Tweet.transaction do
   initial_tweets = get_tweets_in_time_range self.name, (Time.now-1.weeks), Time.now 
initial_tweets.each do |tweet|
    new_tweet = Tweet.new
    ..... 
    new_tweet.created_at = DateTime.strptime tweet.created_at.to_s, '%Y-%m-%d %H:%M:%S %z' 

    new_tweet.save! # you have to add '!', once save failed, it will trigger rolls back.
  end
end