Question

我在尝试匹配我正在开发的应用程序中的多态关联时遇到问题，在用户和食谱的膳食要求之间。在控制台中，我可以使用它 - 如果我将具有等于'[2]'的diet_requirement_ids的用户与具有相同孩子的食谱匹配，则可以正常工作。

然而，当我运行应用程序时，尽管调用了相同的用户和配方，但是将两个评估的方法比较为“false”。

希望很清楚，这里有一些代码可以解释这个：

在控制台中

one = User.first
two = Recipe.first
one.dietary_requirement_ids.any? && ((one.dietary_requirement_ids & two.dietary_requirement_ids) == one.dietary_requirement_ids)
# returns true, as it should

但是，在视图中......

我使用视图可访问的辅助方法，如下所示：

  def dietary_requirement_matcher(one, two)
    one.dietary_requirement_ids.any? && ((one.dietary_requirement_ids & two.dietary_requirement_ids) == one.dietary_requirement_ids)
  end

因此：

<% Recipe.all.each do |recipe| %>
    <li><%= dietary_requirement_matcher(@user, recipe) %></li>
  <% end %> 
<!-- which all return false, including those that shouldn't! -->

我不知道为什么它会在控制台中返回正确的结果而不是视图。我已经尝试了几件事来调试它，如下所示：

将辅助方法更改为以下方法可以正确评估配方（即为用户提供正确的diet_requirement_ids）：

def dietary_requirement_matcher(one, two)
  ([1, 2] & two.dietary_requirement_ids) == [1, 2]
end

@user.inspect拉出正确的用户。但是，@user.dietary_requirement_ids.inspect会拉出一个空数组（尽管仍在控制台中工作）。

我已经检查过用户，并且食谱都已在控制台中正确保存。

这里有一些额外的代码，可以很方便地解决这个问题：

模型

配方

has_many :dietary_requirements, as: :classifiable

用户

has_many :dietary_requirements, as: :classifiable

饮食要求

belongs_to :classifiable, polymorphic: true

控制器

@recipes = Recipe.all
@user = current_user #auth method - debug shows this picking up the correct user in the view, albeit not their dietary requirements

查看（不完整，我在修复时进行调试）

<ul>
  <% Recipe.all.each do |recipe| %>
    <li><%= recipe.name %> = <%= dietary_requirement_matcher(@user, recipe) %></li>
  <% end %>
</ul>

<p><%= dietary_requirement_matcher(@user, Recipe.first) %></p> <!-- returns false, when I'm after true -->
<p><%= @user.dietary_requirements.inspect %></p> <!-- returns '#<ActiveRecord::Associations::CollectionProxy []>' -->

我认为对此的修复可能真的简单，我只是没有发现这个，因为我是一个无知的新手。如果有人可以提供帮助，我会非常感激！史蒂夫。

修改

进行更多挖掘，我有一种感觉，这可能是应用程序在数据库中查找信息的方式的问题。我正在运行类似的逻辑与用户（通过冰箱）和食谱成分（有效！）的多次通过关系，日志显示访问这两个信息的不同路径。

我认为，因为多态关系在搜索数据库时会查找classifiable_id和（至关重要的）classifiable_type，这里可分类的类型变得混杂起来。我有一种感觉，SQLite正在寻找用户的膳食要求，但使用的是'Recipe'而不是'User'的classifiable_type。

任何人都能在这里阐明我的想法吗？那里有什么感觉还是狂人的狂言？这是页面加载时的日志：

Started GET "/fridges/meals" for 151.229.93.203 at 2015-02-17 16:26:42 +0000
Processing by FridgesController#meals as HTML
#code for matching User Ingredients to Recipe Ingredients      
User Load (0.7ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = ? LIMIT 1  [["id", 2]]
   (0.3ms)  SELECT COUNT(*) FROM "recipes"
  Recipe Load (0.3ms)  SELECT "recipes".* FROM "recipes"
  Ingredient Exists (0.2ms)  SELECT  1 AS one FROM "ingredients" INNER JOIN "recipe_ingredients" ON "ingredients"."id" = "recipe_ingredients"."ingredient_id" WHERE "recipe_ingredients"."recipe_id" = ? LIMIT 1  [["recipe_id", 1]]
  Fridge Load (0.2ms)  SELECT  "fridges".* FROM "fridges" WHERE "fridges"."user_id" = ? LIMIT 1  [["user_id", 2]]
   (0.2ms)  SELECT "ingredients".id FROM "ingredients" INNER JOIN "fridge_ingredients" ON "ingredients"."id" = "fridge_ingredients"."ingredient_id" WHERE "fridge_ingredients"."fridge_id" = ?  [["fridge_id", 5]]
   (0.2ms)  SELECT "ingredients".id FROM "ingredients" INNER JOIN "recipe_ingredients" ON "ingredients"."id" = "recipe_ingredients"."ingredient_id" WHERE "recipe_ingredients"."recipe_id" = ?  [["recipe_id", 1]]
  CACHE (0.0ms)  SELECT "ingredients".id FROM "ingredients" INNER JOIN "recipe_ingredients" ON "ingredients"."id" = "recipe_ingredients"."ingredient_id" WHERE "recipe_ingredients"."recipe_id" = ?  [["recipe_id", 1]]
   (0.2ms)  SELECT "dietary_requirements".id FROM "dietary_requirements" WHERE "dietary_requirements"."classifiable_id" = ? AND "dietary_requirements"."classifiable_type" = ?  [["classifiable_id", 2], ["classifiable_type", "User"]]
  Ingredient Load (0.2ms)  SELECT "ingredients".* FROM "ingredients" INNER JOIN "recipe_ingredients" ON "ingredients"."id" = "recipe_ingredients"."ingredient_id" WHERE "recipe_ingredients"."recipe_id" = ?  [["recipe_id", 1]]
  Ingredient Exists (0.1ms)  SELECT  1 AS one FROM "ingredients" INNER JOIN "recipe_ingredients" ON "ingredients"."id" = "recipe_ingredients"."ingredient_id" WHERE "recipe_ingredients"."recipe_id" = ? LIMIT 1  [["recipe_id", 2]]
  CACHE (0.0ms)  SELECT "ingredients".id FROM "ingredients" INNER JOIN "fridge_ingredients" ON "ingredients"."id" = "fridge_ingredients"."ingredient_id" WHERE "fridge_ingredients"."fridge_id" = ?  [["fridge_id", 5]]
   (0.1ms)  SELECT "ingredients".id FROM "ingredients" INNER JOIN "recipe_ingredients" ON "ingredients"."id" = "recipe_ingredients"."ingredient_id" WHERE "recipe_ingredients"."recipe_id" = ?  [["recipe_id", 2]]
  CACHE (0.0ms)  SELECT "ingredients".id FROM "ingredients" INNER JOIN "recipe_ingredients" ON "ingredients"."id" = "recipe_ingredients"."ingredient_id" WHERE "recipe_ingredients"."recipe_id" = ?  [["recipe_id", 2]]
  Ingredient Exists (0.1ms)  SELECT  1 AS one FROM "ingredients" INNER JOIN "recipe_ingredients" ON "ingredients"."id" = "recipe_ingredients"."ingredient_id" WHERE "recipe_ingredients"."recipe_id" = ? LIMIT 1  [["recipe_id", 3]]
  Ingredient Exists (0.1ms)  SELECT  1 AS one FROM "ingredients" INNER JOIN "recipe_ingredients" ON "ingredients"."id" = "recipe_ingredients"."ingredient_id" WHERE "recipe_ingredients"."recipe_id" = ? LIMIT 1  [["recipe_id", 4]]
  Rendered shared/_matcher.html.erb (21.3ms)
  CACHE (0.0ms)  SELECT "recipes".* FROM "recipes"
  CACHE (0.0ms)  SELECT  1 AS one FROM "ingredients" INNER JOIN "recipe_ingredients" ON "ingredients"."id" = "recipe_ingredients"."ingredient_id" WHERE "recipe_ingredients"."recipe_id" = ? LIMIT 1  [["recipe_id", 1]]
  CACHE (0.0ms)  SELECT "ingredients".id FROM "ingredients" INNER JOIN "fridge_ingredients" ON "ingredients"."id" = "fridge_ingredients"."ingredient_id" WHERE "fridge_ingredients"."fridge_id" = ?  [["fridge_id", 5]]
  CACHE (0.0ms)  SELECT "ingredients".id FROM "ingredients" INNER JOIN "recipe_ingredients" ON "ingredients"."id" = "recipe_ingredients"."ingredient_id" WHERE "recipe_ingredients"."recipe_id" = ?  [["recipe_id", 1]]
  CACHE (0.0ms)  SELECT "ingredients".id FROM "ingredients" INNER JOIN "recipe_ingredients" ON "ingredients"."id" = "recipe_ingredients"."ingredient_id" WHERE "recipe_ingredients"."recipe_id" = ?  [["recipe_id", 1]]
  CACHE (0.0ms)  SELECT  1 AS one FROM "ingredients" INNER JOIN "recipe_ingredients" ON "ingredients"."id" = "recipe_ingredients"."ingredient_id" WHERE "recipe_ingredients"."recipe_id" = ? LIMIT 1  [["recipe_id", 2]]
  CACHE (0.0ms)  SELECT "ingredients".id FROM "ingredients" INNER JOIN "fridge_ingredients" ON "ingredients"."id" = "fridge_ingredients"."ingredient_id" WHERE "fridge_ingredients"."fridge_id" = ?  [["fridge_id", 5]]
  CACHE (0.0ms)  SELECT "ingredients".id FROM "ingredients" INNER JOIN "recipe_ingredients" ON "ingredients"."id" = "recipe_ingredients"."ingredient_id" WHERE "recipe_ingredients"."recipe_id" = ?  [["recipe_id", 2]]
  CACHE (0.0ms)  SELECT "ingredients".id FROM "ingredients" INNER JOIN "recipe_ingredients" ON "ingredients"."id" = "recipe_ingredients"."ingredient_id" WHERE "recipe_ingredients"."recipe_id" = ?  [["recipe_id", 2]]
  CACHE (0.0ms)  SELECT  1 AS one FROM "ingredients" INNER JOIN "recipe_ingredients" ON "ingredients"."id" = "recipe_ingredients"."ingredient_id" WHERE "recipe_ingredients"."recipe_id" = ? LIMIT 1  [["recipe_id", 3]]
  CACHE (0.0ms)  SELECT  1 AS one FROM "ingredients" INNER JOIN "recipe_ingredients" ON "ingredients"."id" = "recipe_ingredients"."ingredient_id" WHERE "recipe_ingredients"."recipe_id" = ? LIMIT 1  [["recipe_id", 4]]
#code for matching the User and Recipe Dietary Requirements
  CACHE (0.0ms)  SELECT "recipes".* FROM "recipes"
  CACHE (0.0ms)  SELECT "dietary_requirements".id FROM "dietary_requirements" WHERE "dietary_requirements"."classifiable_id" = ? AND "dietary_requirements"."classifiable_type" = ?  [["classifiable_id", 2], ["classifiable_type", "User"]]
  CACHE (0.0ms)  SELECT "dietary_requirements".id FROM "dietary_requirements" WHERE "dietary_requirements"."classifiable_id" = ? AND "dietary_requirements"."classifiable_type" = ?  [["classifiable_id", 2], ["classifiable_type", "User"]]
  CACHE (0.0ms)  SELECT "dietary_requirements".id FROM "dietary_requirements" WHERE "dietary_requirements"."classifiable_id" = ? AND "dietary_requirements"."classifiable_type" = ?  [["classifiable_id", 2], ["classifiable_type", "User"]]
  CACHE (0.0ms)  SELECT "dietary_requirements".id FROM "dietary_requirements" WHERE "dietary_requirements"."classifiable_id" = ? AND "dietary_requirements"."classifiable_type" = ?  [["classifiable_id", 2], ["classifiable_type", "User"]]
  Recipe Load (0.4ms)  SELECT  "recipes".* FROM "recipes"  ORDER BY "recipes"."id" ASC LIMIT 1
  CACHE (0.0ms)  SELECT "dietary_requirements".id FROM "dietary_requirements" WHERE "dietary_requirements"."classifiable_id" = ? AND "dietary_requirements"."classifiable_type" = ?  [["classifiable_id", 2], ["classifiable_type", "User"]]
  DietaryRequirement Load (0.2ms)  SELECT "dietary_requirements".* FROM "dietary_requirements" WHERE "dietary_requirements"."classifiable_id" = ? AND "dietary_requirements"."classifiable_type" = ?  [["classifiable_id", 2], ["classifiable_type", "User"]]
  Rendered fridges/meals.html.erb within layouts/application (42.3ms)
  Cuisine Load (0.3ms)  SELECT "cuisines".* FROM "cuisines"
  Category Load (0.2ms)  SELECT "categories".* FROM "categories"
  Rendered shared/_header.html.erb (3.3ms)
Completed 200 OK in 593ms (Views: 579.3ms | ActiveRecord: 4.2ms)

Answer 1

我在想，这可能是您的多态关联设置的方式：膳食要求可以属于User或Recipe，因为您使用的是:classifiable参考列双方。我遇到了类似的问题，我的解决方案是将两个单独的引用列添加到多态类中，如下所示：

DietaryRequirement belongs to :owner, polymorphic: true，belongs to :processor, polymorphic: true。然后将以下列添加到Dietary_Requirements表：owner_id, owner_type, processor_id, processor_type。
<强>配方即可。 has_many :dietary_requirements, as: :processor
用户即可。 has_many :dietary_requirements, as: :owner

Rails多态关联显示在控制台中但不在视图中

1 个答案: