ruby-on-rails – Rails 4,双嵌套模型和强参数

2019年7月21日 138次阅读

我对
Ruby on Rails相当新,并立即开始使用rails 4.

我成功地嵌套了食谱和成分模型,以便可以以相同的形式添加它们.接下来我想在成分中嵌入数量,以便可以在同一形式中添加.一切似乎工作正常,直到成分的数量即将插入数据库中,并且从此我相信recipes_controller中的强params有问题.但我会在下面发布完整的代码.
我正在使用simple_form表单.

感谢任何帮助！

这是我的模特：

class Recipe < ActiveRecord::Base
  has_many :comments, dependent: :destroy
  has_many :ingredients, dependent: :destroy
  accepts_nested_attributes_for :ingredients, :reject_if => lambda { |a| a[:name].blank? }, :allow_destroy => true
  validates :title, presence: true
  validates :desc, presence: true
end


class Ingredient < ActiveRecord::Base
  belongs_to :recipe
  has_many :quantities, dependent: :destroy
  accepts_nested_attributes_for :quantities, :reject_if => lambda { |a| a[:name].blank? }, :allow_destroy => true
end

class Quantity < ActiveRecord::Base
  belongs_to :ingredient
end

这是recipes_controller

class RecipesController < ApplicationController

  def new
    @recipe = Recipe.new
    3.times do 
      ingredient = @recipe.ingredients.build
      1.times {ingredient.quantities.build }
    end
  end

  def create
    @recipe = Recipe.new(params[:recipe].permit(:title, :desc, ingredients_attributes: [:id, :recipe_id, :name, :_destroy, quantities_attributes: [:id, :ingredient_id, :amount, :unit, :_destroy]]))

    if @recipe.save
      redirect_to @recipe
    else
      render "new"
    end
  end

  def show
    @recipe = Recipe.find(params[:id])
  end


  def edit
    @recipe = Recipe.find(params[:id])
  end


  def update
    @recipe = Recipe.find(params[:id])

    if @recipe.update(params[:recipe].permit(:title, :desc))
      redirect_to @recipe
    else
      render 'edit'
    end
  end


  def destroy
    @recipe = Recipe.find(params[:id])
    @recipe.destroy

    redirect_to recipes_path
  end





  def index
    @recipes = Recipe.all
  end

  private
    def post_params
      params.require(:recipe).permit(:title, :desc, ingredients_attributes: [:id, :recipe_id, :name, :_destroy, quantities_attributes: [:id, :ingredient_id, :amount, :unit, :_destroy]])
    end
end

然后我使用简单的形式通过部分创建配方,成分和数量的表格.

_形成：

<%= simple_form_for @recipe do |f| %>
    <%= f.error_notification %>


    <%= f.input :title %>
    <%= f.input :desc %>



    <%= f.simple_fields_for :ingredients do |builder| %>

    <%= render "ingredient_fields", :f => builder %>


    <% end %>

    <p class="links">
    <%= link_to_add_association 'add ingredient', f, :ingredients %>
    <p class="links">
    <%= f.error :base%>
    <%= f.submit %>

<% end %>

从_ingredients_fields呈现的内容：

<div class="nested-fields">
    <%= f.input :name, label: "Ingredient" %>



    <%= f.simple_fields_for :quantities do |builder| %>

    <%= render "quantities_fields", :f => builder %>

    <% end %>

    <%= link_to_remove_association "remove", f %>
</div>

从_quantities_fields渲染：[EDITED]

<div class="nested-fields">
    <%= f.input :amount %>
    <%= f.input :unit %>
</div>

尝试添加新配方会产生以下日志语句：

Started POST "/recipes" for 127.0.0.1 at 2013-10-29 14:15:40 +0100
Processing by RecipesController#create as HTML
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"t6LKgDLwAxaU9xo2ipyCM+j1yfVF9WrI8AoGTX+gRkw=", "recipe"=>{"title"=>"Pancakes", "desc"=>"Tasty", "ingredients_attributes"=>{"0"=>{"name"=>"Milk", "quantities_attributes"=>{"0"=>{"amount"=>"1", "unit"=>"Cup"}}, "_destroy"=>"false"}}}, "commit"=>"Create Recipe"}
  [1m[35m (0.1ms)[0m  begin transaction
  [1m[36mSQL (3.5ms)[0m  [1mINSERT INTO "recipes" ("created_at", "desc", "title", "updated_at") VALUES (?, ?, ?, ?)[0m  [["created_at", Tue, 29 Oct 2013 13:15:40 UTC +00:00], ["desc", "Tasty"], ["title", "Pancakes"], ["updated_at", Tue, 29 Oct 2013 13:15:40 UTC +00:00]]
  [1m[35mSQL (0.4ms)[0m  INSERT INTO "ingredients" ("created_at", "name", "recipe_id", "updated_at") VALUES (?, ?, ?, ?)  [["created_at", Tue, 29 Oct 2013 13:15:40 UTC +00:00], ["name", "Milk"], ["recipe_id", 27], ["updated_at", Tue, 29 Oct 2013 13:15:40 UTC +00:00]]
  [1m[36m (7.8ms)[0m  [1mcommit transaction[0m
Redirected to http://www.projectcookbook.dev/recipes/27
Completed 302 Found in 22ms (ActiveRecord: 11.7ms)

最佳答案 你正在为_quantities和_ingredients partials使用类似的渲染,这是错误的.在_quantities_field中你不需要

<%= f.simple_fields_for :quantities do |builder| %>
<%= render "quantities_fields", :f => builder %>
<% end %>

和应该调整

<%= f.input :name, label: "Quantity" %>

在_quantities_fields中.

UPD

我认为问题在于：Ingredient模型中的reject_if-clause.它应该是

:reject_if => lambda { |a| a[:amount].blank? }

在这里你指定数量的条件,而不是成分

代码样式：
1)在控制器中,最好使用私有方法的相关名称作为强参数：recipe_params而不是post_params然后用它来创建新的Recipe @recipe = Recipe.new(recipe_params)

2)食谱,成分和数量之间的当前关联将导致成分重复,如果两个食谱使用类似的食谱.原因是belongs_to,它定义了单个关联.尝试另一种方法(下).

BTW.最近我回答了类似的问题.看看：How do I reference an existing instance of a model in a nested Rails form?

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