骨干和Rails协会：避免JSON HashWithIndifferentAccess错误 [英] Backbone and Rails associations: Avoiding JSON HashWithIndifferentAccess errors

问题描述

我试图让我的骨干协会一个Rails应用程序内的工作，并试图更新现有的模型，当我有困难。具体而言，导轨引发以下错误：

  

在2012-01-04二时36分14秒+1000结果开始PUT/职位/ 2127.0.0.1
  处理由PostsController＃更新为JSON参数：
  {后=> {内容=>Seconderona
  created_at=>2012-01-03T10：51：09Z，ID=> 2，标题=>二测
  后，的updated_at=>2012-01-03T10：51：09Z，意见=> [{}]}，
  ID=>2}后装载（在0.2ms）选择上岗。* FROM上岗WHERE
  上岗。ID=？ LIMIT 1 [ID，2]]警告：不能大规模分配
  受保护的属性：在15ms的ID已完成500内部服务器错误

  
  

的ActiveRecord :: AssociationTypeMismatch（点评（＃70104367824560）
  预计，得了
  ::的ActiveSupport HashWithIndifferentAccess（＃70104367278120））：结果
  应用程序/控制器/ posts_controller.rb：62：在更新中的块结果
  应用程序/控制器/ posts_controller.rb：61：在更新

有几件事情：

这是触发（例如）：

  C = window.router.comments.models [0]
c.save（{内容：更改的内容'}）
 

此外，是的，accepts_nested_attributes_for'是present在模型中。

在（违规）code以下是采取pretty多逐字从thougtbot的骨干在轨道上的电子书，并且我也试​​着为主干关系宝石的文档以下。双方提出这个错误。任何想法AP preciated，code以下

钢轨POST模型

 类帖子＆LT; ActiveRecord的::基地
  的has_many：评论  accepts_nested_attributes_for：评论  高清as_json（选项=无）
    超（。（选件|| {}）合并（包括：{注释：{只：[内容]}}））
  结束
结束
 

钢轨评论模型

 类注释和LT; ActiveRecord的::基地
  belongs_to的：岗位  accepts_nested_attributes_for：岗位  高清as_json（选项=无）
    超（。（选件|| {}）合并（包括：{岗位：{只：[：标题：内容]}}））
  结束
结束
 

BACKBONE POST控制器

 类Backbonerelationaldemo.Models.Post扩展Backbone.Model
  paramRoot：后  初始化：（） - ＆GT;
    评论=新Backbonerelationaldemo.Collections.CommentsCollection
    comments.reset（@get（意见））
    @setComments（评论）  setComments：（评论） -  GT;
    @comments =评论
类Backbonerelationaldemo.Collections.PostsCollection扩展Backbone.Collection
  型号：Backbonerelationaldemo.Models.Post
  网址：'/帖
 

BACKBONE评论控制器

 类Backbonerelationaldemo.Models.Comment扩展Backbone.Model
  paramRoot：评论  初始化：（） - ＆GT;
    如果（@has（'后'））
      @setPost（新Backbonerelationaldemo.Models.Post（@get（'后'）））  setPost：（后） -  GT;
    @post =岗位类Backbonerelationaldemo.Collections.CommentsCollection扩展Backbone.Collection
  型号：Backbonerelationaldemo.Models.Comment
  网址：'/评论
 

解决方案

最近我处理了同样的问题。它实际上不是一个HashWithIndifferentAccess错误：它与如何 accepts_nested_attributes_for 预计PARAMS做

在声明 accepts_nested_attributes_for：评论，Rails将一个参数调用 comments_attributes 对传入PARAMS

问题是，你的JSON重新presentation从骨干来有一个评论属性，而不是一个comments_attributes属性。

您可以通过添加的toJSON函数来发表您的模型修复它的主干端：

 ＃在发表你的模型
的toJSON： - ＆GT;
  ATTRS = _.clone（@属性）
  attrs.comments_attributes = _.clone（@ attributes.comments）
  删除attrs.comments
  ATTRS
 

或者你可以在你的Rails控制器处理：

 ＃在你的帖子控制器
DEF更新
  PARAMS [：comments_attributes] = params.delete（：评论）如果params.has_key？ ：注释
  ＃调用update_attributes方法和其他任何你需要做的
 结束
 

希望这有助于。

I'm trying to get my backbone associations working inside a rails app , and I'm having difficulty when trying to update existing models. Specifically, Rails throws the following error:

Started PUT "/posts/2" for 127.0.0.1 at 2012-01-04 02:36:14 +1000
Processing by PostsController#update as JSON Parameters: {"post"=>{"content"=>"Seconderona", "created_at"=>"2012-01-03T10:51:09Z", "id"=>2, "title"=>"Second test post", "updated_at"=>"2012-01-03T10:51:09Z", "comments"=>[{}]}, "id"=>"2"} Post Load (0.2ms) SELECT "posts".* FROM "posts" WHERE "posts"."id" = ? LIMIT 1 [["id", "2"]] WARNING: Can't mass-assign protected attributes: id Completed 500 Internal Server Error in 15ms

ActiveRecord::AssociationTypeMismatch (Comment(#70104367824560) expected, got ActiveSupport::HashWithIndifferentAccess(#70104367278120)):
app/controllers/posts_controller.rb:62:in block in update'
app/controllers/posts_controller.rb:61:inupdate'

A few things:

This is triggered on (for example):

c = window.router.comments.models[0]
c.save({content: 'Changed content'})

Also, yes, 'accepts_nested_attributes_for' is present in the model.

The (offending) code below is taken pretty much verbatim from thougtbot's "backbone on rails" ebook, and I've also tried following the documentation for the backbone-relational gem. Both raise this error. Any ideas appreciated, code below

RAILS 'POST' MODEL

class Post < ActiveRecord::Base
  has_many :comments

  accepts_nested_attributes_for :comments

  def as_json(options = nil)
    super((options || {}).merge(include: { comments: { only: [content] } } ))
  end
end

RAILS 'COMMENT' MODEL

class Comment < ActiveRecord::Base
  belongs_to :post

  accepts_nested_attributes_for :post

  def as_json(options = nil)
    super((options || {}).merge(include: { post: { only: [:title, :content]}}))
  end
end

BACKBONE POST CONTROLLER

class Backbonerelationaldemo.Models.Post extends Backbone.Model
  paramRoot: 'post'

  initialize: () ->
    comments = new Backbonerelationaldemo.Collections.CommentsCollection
    comments.reset(@get('comments'))
    @setComments(comments)

  setComments: (comments) ->
    @comments = comments


class Backbonerelationaldemo.Collections.PostsCollection extends Backbone.Collection
  model: Backbonerelationaldemo.Models.Post
  url: '/posts'

BACKBONE COMMENTS CONTROLLER

class Backbonerelationaldemo.Models.Comment extends Backbone.Model
  paramRoot: 'comment'

  initialize: () ->
    if (@has('post')) 
      @setPost(new Backbonerelationaldemo.Models.Post(@get('post')))

  setPost: (post) ->
    @post = post

class Backbonerelationaldemo.Collections.CommentsCollection extends Backbone.Collection
  model: Backbonerelationaldemo.Models.Comment
  url: '/comments'

解决方案

I dealt with the same issue recently. It's actually not a HashWithIndifferentAccess error: it has to do with how accepts_nested_attributes_for expects params.

When you declare accepts_nested_attributes_for :comments, Rails looks for a parameter call comments_attributes on the incoming params.

The problem is that your JSON representation coming from Backbone has a "comments" property instead of a "comments_attributes" property.

You could fix it on the Backbone side by adding a toJSON function to your Post model:

# in your Post model
toJSON: ->
  attrs = _.clone(@attributes)
  attrs.comments_attributes = _.clone(@attributes.comments)
  delete attrs.comments
  attrs

Or you could handle it in your Rails controller:

# in your Posts controller
def update
  params[:comments_attributes] = params.delete(:comments) if params.has_key? :comments
  # call to update_attributes and whatever else you need to do
 end

Hopefully this helps.

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