在Rails 5中添加评论文章（深度嵌套资源）

Question

我有一个Rails应用程序，它有三个主要模型：Qn，Ans和Comments。我一直在做1层深的嵌套资源，但这三个资源是深嵌套（评论是浅层嵌套），他们都显示在单一视图，这使得它很混乱。

在一个像这样的网址：http://localhost:3000/questions/2，用户可以看到所有使用循环显示的问题：@ question.answers。在每个这些答案中，用户可以看到使用循环显示的answer.comments。在每个回答以下，用户也可以提交新评论。

但尝试多次实施1）循环显示所有评论和2）形式的新评论后，我总是得到的线沿线的一些错误：

undefined method `model_name' for {:url=>"https://stackoverflow.com/questions/4/answers/2/comments/new"}:Hash 

于是，我就在PARAMS通过@commentable而不是答案，或指向特定控制器和操作等，但这些方法都没有工作。我猜测我的控制器有一个问题，但我似乎无法弄清楚。

routes.rb中（上中省略）

# Resources 
resources :sessions 
resources :users 
resources :bookmarks # to be implemented later 

resources :questions do 
    resources :answers do 
    resources :comments, shallow: true 
    end 
end 

问题模型

class Question < ApplicationRecord  
    has_many :answers 
    has_many :bookmarks #later 
end 

答型号：

class Answer < ApplicationRecord 
    belongs_to :question 
    has_many :comments, as: :commentable 

    has_many :likes, as: :likeable 
    validates :answercontent, length: {minimum: 50} 
end 

Comment模型：

class Comment < ApplicationRecord 
    belongs_to :commentable, polymorphic: true 
end 

的show.html。ERB（的QuestionsController）

<% @question.answers.each do |answer| %> 
// ommited 
<!-- Comments --> 
<% answer.comments.each do |comment| %> 
    <%= comment.content %> 
    <br> 
<% end %> 

<!-- Submit new comment --> 
<%= form_for(url: new_question_answer_comment_path, comment: {answer_id: answer.id, question_id: @question.id}) do |f| %> 
    <%= f.text_area :content %> 
    <%= f.submit "Submit" %> 
<% end %> 
<% end %> 

QuestionsController（新，创建，销毁中省略为简洁起见）

class QuestionsController < ApplicationController 
def index 
    @questions = Question.all 
end 

def show 
    @question = Question.find(params[:id]) 
    @answers = Answer.all 

    # Delete only appears when num_ans is 0 
    @deletable = (current_user== User.find(@question.user_id)) && (@question.answers.all.size==0) 

end 

private 
    def question_params 
    params.require(:question).permit(:picture_url, :country, :educational_level, :topic) 
    end 

end 

AnswersController（编辑，更新，破坏中省略为简洁起见）

class AnswersController < ApplicationController 

def create 
    @question = Question.find(params[:question_id]) 
    @answer = @question.answers.create(answer_params) 
    @answer.question_id = @question.id 
    @answer.user_id = current_user.id 

    if @answer.save 
     redirect_to @question 
    else 
     render :new 
    end 
end 

private 
    def answer_params 
    params.require(:answer).permit(:user_id, :question_id, :answercontent) 
    end  
end 

评论控制器

class CommentsController < ApplicationController 
before_filter: load_commentable 

def index 
    @commentable = Answer.find(params[:answer_id]) 
    @comments = @commentable.comments 
end 

def new 
    @comment = @commentable.comments.new 
end 

def create 
    @comment = @commentable.comments.new(params[:comment]) 
    if @comment.save 
    redirect_to @commentable 
    else 
    render :new 
    end 
end 

# From RailsCast ep.154 
private 
def load_commentable 
    resource, id = request.path.split('/')[1,2] 
    @commentable = resource.singularize.classify.constantize.find(id) 
end 
end 

的路由 现在是相当混乱，所以我将只是张贴在那里的意见是：提前为帮助

question_answer_comments GET /questions/:question_id/answers/:answer_id/comments(.:format)  comments#index 
         POST /questions/:question_id/answers/:answer_id/comments(.:format)  comments#create 
new_question_answer_comment GET /questions/:question_id/answers/:answer_id/comments/new(.:format) comments#new 
      edit_comment GET /comments/:id/edit(.:format)          comments#edit 
       comment GET /comments/:id(.:format)           comments#show 
         PATCH /comments/:id(.:format)           comments#update 
         PUT /comments/:id(.:format)           comments#update 
         DELETE /comments/:id(.:format)           comments#destroy 

感谢。

更新：

为了让你对我有什么企图解决方案的更多信息： 1.传递两个参数，如：

<%= form_for([answer, @comment], url: new_question_answer_comment_path(answer.id, @question.id)) do |f| %> 

递给我：

First argument in form cannot contain nil or be empty 

使用@commentable（这基本上是答案）给了我一个错误，说'@ commentable.id中的id不存在@commentable没有'。

所以我觉得这个问题是答案或@commentable为零。但是我也在循环和控制器中指定了它。那么我还有什么可以尝试的？

Answer 1

form_for预计记录为第一个参数，你的情况应该是评论实例。此外new_question_answer_comment_path预计值question_id和answer_id键，因为你是创建一个新的评论，则路线应question_answer_comments不new_question_answer_comment所以你form_for应该

<%= form_for Comment.new,url: question_answer_comments_path(@question,answer) do |f| %> 
    <%= f.text_area :content %> 
    <%= f.submit "Submit" %> 
<% end %> 

或只是

<%= form_for [Comment.new,@question,answer] do |f| %> 
    <%= f.text_area :content %> 
    <%= f.submit "Submit" %> 
<% end %>