轨道4哈希

Question

伪retrive模型协会（嵌套ATTRS）

model User 
    has_many :books 
model Book 
    belongs_to :user 

我想是

pseudo User.first.with(:books) 


result => Hash {user: {name: "john_doe", 
        books: {0: {title: "book"}}}} 

我怎样才能做到这一点？

EDIT 

我几乎没有：User.preload（：书籍）。首先 - > retrives嵌套， 但现在模型如何serialilze它上面的？ EDIT ve done it！

user = User.preload(:books).first 
hash = user.as_json 
books = user.books 
x = Hash[(0...books.size).zip books] 
hash[:books] = x 

Answer 1

应用程序/模型/ user.rb

class User < ActiveRecord::Base 
    has_many :books 

    def as_json(options = nil) 
    super({ only: [:id, :name], include: :books }) 
    end 
end 

这样，您可以使用as_json这样的：

>> User.first.as_json 
=> {"id"=>1, "name"=>"john_doe", "books"=>[ 
    {"user_id"=>1, "id"=>1, "title"=>"book", 
    "created_at"=>Fri, 06 Feb 2015 09:25:12 UTC +00:00, 
    "updated_at"=>Fri, 06 Feb 2015 09:25:12 UTC +00:00}]} 
>> 

也有一些宝石，其提供了类似的结果。有关更多信息，请参见http://robots.thoughtbot.com/better-serialization-less-as-json。