ruby-on-rails – Rails：渴望加载as_json包含

发布时间：2020-12-17 04:30:55 所属栏目：百科来源：网络整理

导读：render :json = { "playlist" = playlist_description,"songs" = @playlist.songs.as_json(:include = {:playlist_songs = {:only = [:id,:position]}}) } 上面的代码导致对数据库的1 N个查询,一个用于加载每首歌曲的playlist_songs. 播放列表预装在@playlis

render :json => {
    "playlist" => playlist_description,"songs" => @playlist.songs.as_json(:include => {:playlist_songs => {:only => [:id,:position]}})
  }

上面的代码导致对数据库的1 N个查询,一个用于加载每首歌曲的playlist_songs.
播放列表预装在@playlist中.

这太慢了,我该如何优化？

解决方法

我猜：你现在不急于加载playlist_songs.您当前正在等待as_json调用 – 之后所有歌曲都已加载 – 然后代码必须迭代每首歌曲然后获取playlist_songs.

我的猜测(这是完全未经测试的,可能包含错误)

@playlist.songs.all(:include => :playlist_songs).as_json(:include => {:playlist_songs => {:only => [:id,:position]}})

AFAICT,这应该首先加载所有歌曲和playlist_songs …然后渲染为json.

（编辑：李大同）

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