在Rails 5.0.0.beta3，-api选项中使用accepts_nested_attributes_for时出现问题

我正在使用Rails 5.0.0.beta3，使用rails new上的-app选项构建一个仅限API的应用程序，而我在使用accepts_nested_attributes_for时遇到了问题。

在我的应用程序中，具有嵌套属性的对象的创建（或新的，然后保存！）失败，并显示父父对象必须存在的消息。

为了测试，我制作了一个新的应用程序，只使用了ANAF文档中的成员和post的测试用例：

class Member < ApplicationRecord has_many :posts accepts_nested_attributes_for :posts end 

和

 class Post < ApplicationRecord belongs_to :member end 

（这些类定义是由Rails脚手架生成器生成的，所以inheritance自ApplicationRecord，而不是ActiveRecord :: Base，但是根据这篇文章 ，这并不重要。）

对于已定义的类别，以及创建和运行的匹配迁移，我启动了Rails控制台并按照文档中的步骤操作：

 params = { member: { name: 'joe', posts_attributes: [ { title: 'Kari, the awesome Ruby documentation browser!' }, { title: 'The egalitarian assumption of the modern citizen' }, { title: '', _destroy: '1' } # this will be ignored ]}} {:member=>{:name=>"joe", :posts_attributes=>[{:title=>"Kari, the awesome Ruby documentation browser!"}, {:title=>"The egalitarian assumption of the modern citizen"}, {:title=>"", :_destroy=>"1"}]}} 

然后：

 >> member = Member.create(params[:member]) (0.2ms) BEGIN (0.4ms) ROLLBACK # 

没有快乐！

当我将create拆分为new，然后保存！时，我得到相同的结果，有一个更清晰的错误：

 >> member = Member.new(params[:member]) # 

member.save！
（15.0ms）BEGIN ActiveRecord :: RecordInvalid：validation失败：post成员必须存在
来自/Users/pauldavis/.rvm/gems/ruby-2.2.4/bundler/gems/rails-b785064958f9/activerecord/lib/active_record/validations.rb:78:in raise_validation_error'
from /Users/pauldavis/.rvm/gems/ruby-2.2.4/bundler/gems/rails-b785064958f9/activerecord/lib/active_record/validations.rb:50:in raise_validation_error'
from /Users/pauldavis/.rvm/gems/ruby-2.2.4/bundler/gems/rails-b785064958f9/activerecord/lib/active_record/validations.rb:50:in raise_validation_error'
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有关为什么文档中的示例代码有效的任何想法？ 我的环境可能有问题吗？ -api选项是否会破坏ActiveRecord中的某些内容？ 顺便说一下，我正在使用PostgreSQL

谢谢！

Answer 1

我也遇到了同样的问题。
似乎规范已经从Rails 5改变了。
通过选择，以及之前和相同的操作。

belongs_to应默认为required：true＃18233

 class Post < ApplicationRecord belongs_to :member, optional: true end 

我的笨拙可能会说英语，但......

Answer 2

这是一个回归报告为rails＃25198 。 正如所指出的，您可以使用inverse_of作为变通方法。

计划在5.0.1中修复。

Answer 3

我有同样的问题，我在https://github.com/rails/rails/issues/18233找到了解决方案

只需添加

 class Post < ApplicationRecord belongs_to :member, required: false end 

对于Rails 5中的accepts_nested_attributes_for似乎有问题，因此您需要向您的子模型添加required: false 。

Answer 4

我发现向关联添加inverse_of选项允许accepts_nested_attributes工作。 比猴子修补好，仍然允许validation关联

Answer 5

在我的Rails 5 beta 3应用程序中，我遇到了accepts_nested_attributes_for问题，看起来好像有问题。 理想情况下，应该提交错误报告，但我们没有时间正确地完成它。 我们有以下设置：

 accepts_nested_attributes_for :attachments, allow_destroy: true 

最终，我们不得不在模型中修补方法，如下所示：

  def attachments_attributes=(attributes) attributes.reject! do |_attachment| if _attachment = Attachment.find(_attachment['id']) if _attachment.drop_id.nil? attachments << _attachment next true end end next false end # assign_nested_attributes_for_collection_association(:attachments, attributes) end 

唯一的事情是，带有assign_nested_attributes_for_collection_association的最后一个（注释掉的行）有一些问题，但希望这会让你知道如何解决这个问题。