No route matches {:action=>"edit", :controller=>"comments", :article_id=>nil, :id=>nil} for editing comments for article in ruby on rails blog

Question

My app was working fine until I decided to add edit functionality for comments. Before it, I could view particular article but not now. Now I am getting routing error as No route matches {:action=>"edit", :controller=>"comments", :article_id=>nil, :id=>nil} when I try to access particular article(articles/show) which has some comments. Actually I was trying to implement comment editing functionality for article. For this,I have put "Edit" link for comments in comments/_comment.html.erb.It is noticeable that I do get this error only if article has comments and when article does not have comments , it does not get. I have separate views for articles and comments.

comments_controller.rb

    class CommentsController < ApplicationController
         before_filter :user_signed_in, except: [:create]
        def new
          @comment = Comment.new
        end

        def create
          @article = Article.find(params[:article_id])
          @comment = @article.comments.build(params[:comment])
          @comment.user_id = current_user.id
          @comment.save
            flash[:success] = "Comment created!"
            redirect_to article_path(@comment.article)
        end

        def edit
        @comment = Comment.find(params[:id])
        end

        def update
         @comment = Comment.find(params[:id])
         @article = @comment.article
         respond_to do |format|
          if @comment.update_attributes(params[:comment])
            redirect_to @article_path(@article)
          else
           render :action => "edit" 
          end
        end

        def destroy
         @comment = Comment.find(params[:id])
        @article = Article.find(params[:article_id])
        @comment.destroy
           redirect_to @article_path(@artilce) 
        end

    end

comments/edit.html.erb

    <h3>Editing comment</h3>
    <%= render :partial => 'comment_form' %>

comments/_comment_form.html.erb

    <%= form_for ([@article, @article.comments.build]), :required => true do |f| %>
    <%= f.hidden_field :article_id %> 
    <%= f.text_area :content, :style => "width:727px; height:100px; border: 1px solid #999999;margin-top:80px; background-color:#FFFFFF;margin-left:-33px" %>
        <div class="actions">
        <%= f.submit "Add Comment", :style => "margin-right:20px; margin-left:560px; background-color:#66C9Ef; color:#FFFFFF; border: 0px solid #82b548; border-radius: 3px 3px 3px 3px; font-size: 1.3rem;" %>
      </div>
    <% end %>

comments/comment.html.erb ( here i have given link for editing comments for an article)

    <% if @article.comments.count  >= 1 %>
      <div style="border: px solid #66c9ee;border-radius: 0px 0px 0px 0px;margin: 10px -30px 15px; padding:     10px 15px 25px; background: none repeat scroll 0 0 #F2F2F2; width:700px; font-size: 1.2em;border-bottom: 0px solid #DDDDDD;">
          <%= comment.content %>
             <div id="tabula"> 
                <ul id="tabula">
                 <li> <div style="color: #0077CC;margin-rigth:200px; font-size: 1.0em;margin-top:4px;background-color:#;"> <%= comment.user.username if comment.user %></div></li>
                 <li> <div style="color: #0077CC; background-color:; margin-top:4px; margin-left:25px;"> <p> <%= time_ago_in_words(comment.created_at.in_time_zone("Asia/Calcutta"))  unless comment.created_at.nil? %>  </p></div></li>
                 <li> <div style="color: #0077CC; background-color:; margin-top:4px; margin-left:25px;"> <%= link_to "edit", edit_article_comment_path(@article,comment) %> </div></li>
                </ul>
               </div>
              </div>
        <% else %>
            <div style="color:#0077CC;margin-left:25px;font-size:1.4em;"> be first to comment</div>
      <% end %>

rake routes result.(not complete)

            articles GET    /articles(.:format)                               articles#index
                     POST   /articles(.:format)                               articles#create
         new_article GET    /articles/new(.:format)                           articles#new
        edit_article GET    /articles/:id/edit(.:format)                      articles#edit
             article GET    /articles/:id(.:format)                           articles#show
                     PUT    /articles/:id(.:format)                           articles#update
                     DELETE /articles/:id(.:format)                           articles#destroy
     dashboard_index GET    /dashboard(.:format)                              dashboard#index
                     POST   /dashboard(.:format)                              dashboard#create
       new_dashboard GET    /dashboard/new(.:format)                          dashboard#new
      edit_dashboard GET    /dashboard/:id/edit(.:format)                     dashboard#edit
           dashboard GET    /dashboard/:id(.:format)                          dashboard#show
                     PUT    /dashboard/:id(.:format)                          dashboard#update
                     DELETE /dashboard/:id(.:format)                          dashboard#destroy


                   tags GET    /tags(.:format)                                   tags#index
                         POST   /tags(.:format)                                   tags#create
                 new_tag GET    /tags/new(.:format)                               tags#new
                edit_tag GET    /tags/:id/edit(.:format)                          tags#edit
                     tag GET    /tags/:id(.:format)                               tags#show
                         PUT    /tags/:id(.:format)                               tags#update
                         DELETE /tags/:id(.:format)                               tags#destroy
        article_comments GET    /articles/:article_id/comments(.:format)          comments#index
                         POST   /articles/:article_id/comments(.:format)          comments#create
     new_article_comment GET    /articles/:article_id/comments/new(.:format)      comments#new
    edit_article_comment GET    /articles/:article_id/comments/:id/edit(.:format) comments#edit
         article_comment GET    /articles/:article_id/comments/:id(.:format)      comments#show
                         PUT    /articles/:article_id/comments/:id(.:format)      comments#update
                         DELETE /articles/:article_id/comments/:id(.:format)      comments#destroy
                         GET    /articles(.:format)                               articles#index
                         POST   /articles(.:format)                               articles#create
                         GET    /articles/new(.:format)                           articles#new
                         GET    /articles/:id/edit(.:format)                      articles#edit
                         GET    /articles/:id(.:format)                           articles#show
                         PUT    /articles/:id(.:format)                           articles#update
                         DELETE /articles/:id(.:format)                           articles#destroy

routes.rb

    Mau::Application.routes.draw do
      devise_for :users
      root :to => 'articles#index'
      resources :articles
      resources :dashboard
      resources :tags
      resources :articles do
      resources :comments
    end
    end

comments_comment.html.erb

<% if @article.comments.count  >= 1 %>
  <div style="border: px solid #66c9ee;border-radius: 0px 0px 0px 0px;margin: 10px -30px 15px; padding:     10px 15px 25px; background: none repeat scroll 0 0 #F2F2F2; width:700px; font-size: 1.2em;border-bottom: 0px solid #DDDDDD;">
      <%= comment.content %>
         <div id="tabula"> 
            <ul id="tabula">
             <li> <div style="color: #0077CC;margin-rigth:200px; font-size: 1.0em;margin-top:4px;background-color:#;"> <%= comment.user.username if comment.user %></div></li>
             <li> <div style="color: #0077CC; background-color:; margin-top:4px; margin-left:25px;"> <p> <%= time_ago_in_words(comment.created_at.in_time_zone("Asia/Calcutta"))  unless comment.created_at.nil? %>  </p></div></li>
             <li> <div style="color: #0077CC; background-color:; margin-top:4px; margin-left:25px;"> <%= link_to "edit", edit_article_comment_path(@article ,@comment) %> </div></li>
            </ul>
           </div>
          </div>
    <% else %>
        <div style="color:#0077CC;margin-left:25px;font-size:1.4em;"> be first to comment</div>
  <% end %>

Answer 1

<% if @article.comments.count  >= 1 %>
  <div "...">
    <%= comment.content %> # <-- This.

I am putting my suspicions on <%= comment.content %> and other comment variables found in comments_comment.html.erb and comments/comment.html.erb.

Seems plausible to me, since you don't receive errors if the article in question has no comments, as @article.comments.count >= 1 returns false.

To have a working comment variable, insert a loop after the if statement:

<% if @article.comments.count  >= 1 %>
  <div "...">
    <% @article.comments.each do |comment| %> # <-- This.
      <%= comment.content %>
      ...
    <% end %> # Remember to close the loop.
  </div>
<% else %>
...

Also, take note to use comment instead of @comment in edit_article_comment_path in comment/_comment.html.erb.

Answer 2

You are only showing the comments if the method #count returns 1 or greater. When you call the method count it count directly on the database, in the the case of an article without any comments, it will render nothing, so that's because you can see an article without comments.

But, when a comment exists, you are building a new comment to show up in the form and also trying to create a edit link for it.

So my solution is, change your form_for, since you dont need to resend all of your comments again, pass a new comment as parameter, instead of build one on the comments collection. Then on the other view, you can create a edit link for each of the persisted comments.