我的 rails 嵌套模型无法识别 _destroy 属性

Question

我有一个父模型（鸡尾酒）和一个子模型（剂量）。

我有一个嵌套表单，我希望能够在其中 create/delete 随时随地添加对象。

创建部分在强参数中没有 _destroy 属性的情况下工作，但是当我将 _destroy 添加到属性散列以便能够删除时，我得到错误 unknown attribute '_destroy' for Dose.我不确定我哪里错了。

我还认为我的代码过于复杂，应该有一种比我正在做的更简单的方法来创建剂量（甚至需要 add_doses 方法吗？）。如果我能得到一些反馈，我将不胜感激。

鸡尾酒：

class Cocktail < ApplicationRecord
  validates :name, uniqueness: true, presence: true

  has_many :doses, dependent: :destroy
  has_many :ingredients, through: :doses
  accepts_nested_attributes_for :doses, allow_destroy: true
end

剂量：

class Dose < ApplicationRecord
  validates :description, presence: true
  belongs_to :cocktail
  belongs_to :ingredient
  validates :cocktail, uniqueness: { scope: :ingredient }
 end

控制器：

class CocktailsController < ApplicationController
  before_action :set_task, only: %i[show edit update]

  def index
    @cocktails = Cocktail.all
  end

  def show; end

  def new
    @cocktail = Cocktail.new
    @cocktail.doses.build
  end

  def create
    @cocktail = Cocktail.new(cocktail_params)
    @cocktail.save
    add_doses
    redirect_to cocktails_path
  end

  def edit; end

  def update
    @cocktail.update(cocktail_params)
    add_doses
    redirect_to cocktail_path(@cocktail)
  end

  private

  def set_task
    @cocktail = Cocktail.find(params[:id])
  end

  def cocktail_params
    params[:cocktail][:name] = params[:cocktail][:name].downcase.titleize
    params.require(:cocktail).permit(:name)
  end

  def add_doses
    @cocktail.doses.destroy_all
    strong_params = params.require(:cocktail).permit(doses_attributes: [:description, :ingredient_id, :_destroy, :id])
    params[:cocktail][:doses_attributes].each_key do |key|
      @cocktail.doses.create(strong_params[:doses_attributes][key])
    end
  end
end

我的主窗体视图：

<%= simple_form_for @cocktail do |f| %>
  <%= f.input :name, required: true %>
  <%= f.nested_fields_for :doses do |dose| %>
    <%= render '/cocktails/partials/doses_fields', f: dose %>
  <% end %>
  <div class="btn-group" role="group" aria-label="Basic example">
    <%= link_to_add_association 'add dose', f, :doses, partial: '/cocktails/partials/doses_fields', class: "btn btn-secondary" %>
    <%= f.button :submit, class: "btn btn-secondary" %>
  </div>
<% end %>

我对添加新剂量的部分看法：

<div class='nested-fields'>
  <div class="field">
    <%= f.text_field :description %>
  </div>
    <%= f.association :ingredient, collection: Ingredient.all %>
    <%= link_to_remove_association "remove dose", f %>
</div>

如果您还想指出我的代码的所有错误，请不要退缩，做最坏的;)

Answer 1

首先修复您的 #create 和 #update 方法，以便它们在您重定向之前检查记录是否实际保留！

然后将嵌套参数添加到白名单并取消 add_doses 方法，这是一种创造性但极其有缺陷的尝试，旨在复制嵌套属性提供的功能。

class CocktailsController < ApplicationController
  before_action :set_cocktail, only: %i[show edit update]

  def index
    @cocktails = Cocktail.all
  end

  def show; end

  def new
    @cocktail = Cocktail.new
    @cocktail.doses.build
  end

  def create
    @cocktail = Cocktail.new(cocktail_params)
    if @cocktail.save
      redirect_to cocktails_path
    else
      render :new
    end
  end

  def edit; end

  def update
    if @cocktail.update(cocktail_params)
      redirect_to @cocktail
    else
      render :edit
    end
  end

  private

  def set_cocktail
    @cocktail = Cocktail.find(params[:id])
  end

  def cocktail_params
    # this should be done in the model
    params[:cocktail][:name] = params[:cocktail][:name].downcase.titleize
    params.require(:cocktail)
          .permit(
             :name,
             doses_attributes: [
               :id,
               :_destroy,
               :description,
               :ingredient_id
             ]
          )
  end
end

如果您想让用户删除嵌套记录，只需创建一个复选框：

<div class='nested-fields'>
  <div class="field">
    <%= f.text_field :description %>
  </div>
    <%= f.association :ingredient, collection: Ingredient.all %>
    <%= f.input :_destroy, as: :boolean, label: 'Remove' %>
</div>

您还需要修复您的验证：

class Dose < ApplicationRecord
  validates :description, presence: true
  belongs_to :cocktail
  belongs_to :ingredient
  validates :cocktail_id, uniqueness: { scope: :ingredient_id }
end

创建唯一性验证时，您需要将其设置为验证实际列而非关联的唯一性。

我的 rails 嵌套模型无法识别 _destroy 属性

My rails nested model isn't recognizing _destroy attribute

ruby

ruby-on-rails

nested-forms

strong-parameters