Rails 中的多态关联问题
我正在尝试关注 Ryan Bates 截屏视频，但收到错误消息。我做了以下操作：
1）创建表
class CreateComments < ActiveRecord::Migration
def self.up
create_table :comments do |t|
t.references :commentable, :polymorphic => true
2）设置模型
class Comment < ActiveRecord::Base
belongs_to :commentable, :polymorphic => true
class Product < ActiveRecord::Base
has_and_belongs_to_many :categories
has_many :comments, :as => :commentable
class Category < ActiveRecord::Base
has_and_belongs_to_many :products
has_many :comments, :as => :commentable
3）更改控制器显示操作
class CategoriesController < ApplicationController
def show
@category = Category.find_by_permalink(params[:id])
@commentable = @category
@comment = Comment.new(:commentable => @category)
end
4）将表单添加到模板views/categories/show.html.erb
<% form_for [@commentable, Comment.new] do |f| %>
<p>
<%= f.label :name %><br />
<%= f.text_field :name %>
</p>
<p>
<%= f.label :content %><br />
<%= f.text_area :content %>
</p>
<p>
<%= f.submit 'Submit' %>
</p>
<% end %>
5）之后我通过访问/categories/my-收到错误消息 ？
NoMethodError in Categories#show
undefined method `category_comments_path' for #<ActionView::Base:0x69a9254>
你能帮我理解我做错了什么吗 在原始截屏视频中，Ryan 使用嵌套关联访问 /categories/permalink/comments 的评论，但我不需要。我想直接从我的多态对象编写注释。 谢谢
I am trying to follow Ryan Bates screencast but have an error message. I did the following:
1) Create table
class CreateComments < ActiveRecord::Migration
def self.up
create_table :comments do |t|
t.references :commentable, :polymorphic => true
2) Setup models
class Comment < ActiveRecord::Base
belongs_to :commentable, :polymorphic => true
class Product < ActiveRecord::Base
has_and_belongs_to_many :categories
has_many :comments, :as => :commentable
class Category < ActiveRecord::Base
has_and_belongs_to_many :products
has_many :comments, :as => :commentable
3) Change controller show action
class CategoriesController < ApplicationController
def show
@category = Category.find_by_permalink(params[:id])
@commentable = @category
@comment = Comment.new(:commentable => @category)
end
4) Add a form to template views/categories/show.html.erb
<% form_for [@commentable, Comment.new] do |f| %>
<p>
<%= f.label :name %><br />
<%= f.text_field :name %>
</p>
<p>
<%= f.label :content %><br />
<%= f.text_area :content %>
</p>
<p>
<%= f.submit 'Submit' %>
</p>
<% end %>
5) After that I get error message by accessing /categories/my-category-permalink
NoMethodError in Categories#show
undefined method `category_comments_path' for #<ActionView::Base:0x69a9254>
Could you help me to understand what I did wrong?
In the original screencast Ryan accesses comments by /categories/permalink/comments using nested associations, but I don't need that. I want to write comments directly from my polymorphic objects.
Thanks
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问题出在路线设置上。我认为由于我不使用嵌套资源，因此我可以保持路由不变。好吧，现在我知道我错了......:)添加这个来解决问题：
The problem was in routes settings. I thought that since I don't use nested resources, I can keep routes unchanged. Well, now I know that I was wrong... :) Add this to fix the problem: