在Rails 5中添加評論文章（深度嵌套資源）

Question

我有一個Rails應用程序，它有三個主要模型：Qn，Ans和Comments。我一直在做1層深的嵌套資源，但這三個資源是深嵌套（評論是淺層嵌套），他們都顯示在單一視圖，這使得它很混亂。

在一個像這樣的網址：http://localhost:3000/questions/2，用戶可以看到所有使用循環顯示的問題：@ question.answers。在每個這些答案中，用戶可以看到使用循環顯示的answer.comments。在每個回答以下，用戶也可以提交新評論。

但嘗試多次實施1）循環顯示所有評論和2）形式的新評論後，我總是得到的線沿線的一些錯誤：

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

於是，我就在PARAMS通過@commentable而不是答案，或指向特定控制器和操作等，但這些方法都沒有工作。我猜測我的控制器有一個問題，但我似乎無法弄清楚。

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 

問題模型

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

答型號：

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，創建，銷燬中省略爲簡潔起見）

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（編輯，更新，破壞中省略爲簡潔起見）

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 

評論控制器

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 現在是相當混亂，所以我將只是張貼在那裏的意見是：提前爲幫助

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 

感謝。

更新：

爲了讓你對我有什麼企圖解決方案的更多信息： 1.傳遞兩個參數，如：

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

遞給我：

First argument in form cannot contain nil or be empty 

使用@commentable（這基本上是答案）給了我一個錯誤，說'@ commentable.id中的id不存在@commentable沒有'。

所以我覺得這個問題是答案或@commentable爲零。但是我也在循環和控制器中指定了它。那麼我還有什麼可以嘗試的？

Answer 1

form_for預計記錄爲第一個參數，你的情況應該是評論實例。此外new_question_answer_comment_path預計值question_id和answer_id鍵，因爲你是創建一個新的評論，則路線應question_answer_comments不new_question_answer_comment所以你form_for應該

<%= 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 %>