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The action 'show' could not be found for CommentsController - Ruby Tutorial

I am trying to follow the following guide for starting Ruby on Rails. Everything went well until I try to destroy (delete comments).

I receive the following error:
The action 'show' could not be found for CommentsController

I will post my code below.

http://guides.rubyonrails.org/getting_started.html

comments_controller.rb

class CommentsController < ApplicationController

http_basic_authenticate_with name: "dhh", password: "secret", only: :destroy

def create
@article = Article.find(params[:article_id])
@comment = @article.comments.create(comment_params)
redirect_to article_path(@article)
end

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

private
def comment_params
params.require(:comment).permit(:commenter, :body)
end

end


articles_controller

class ArticlesController < ApplicationController

http_basic_authenticate_with name: "dhh", password: "secret", except: [:index, :show]

def index
@articles = Article.all
end

def show
@article = Article.find(params[:id])
end

def new
@article = Article.new
end

def edit
@article = Article.find(params[:id])
end

def create
@article = Article.new(article_params)

if @article.save
redirect_to @article
else
render 'new'
end
end

def update
@article = Article.find(params[:id])

if @article.update(article_params)
redirect_to @article
else
render 'edit'
end
end

def destroy
@article = Article.find(params[:id])
@article.destroy

redirect_to articles_path
end

private
def article_params
params.require(:article).permit(:title, :text)
end
end


routes.rb

Rails.application.routes.draw do

resources :articles do
resources :comments
end

root 'welcome#index'
end


article.rb

class Article < ActiveRecord::Base

has_many :comments, dependent: :destroy

validates :title, presence: true,
length: { minimum: 5}
end


comment.rb

class Comment < ActiveRecord::Base
belongs_to :article
end


articles/index.html.erb

<h1>Listing Articles</h1>

<%= link_to 'New article', new_article_path %>

<table>
<tr>
<th>Title</th>
<th>Text</th>
<th colspan="3"></th>
</tr>

<% @articles.each do |article| %>
<tr>
<td><%= article.title %></td>
<td><%= article.text %></td>
<td><%= link_to 'Show', article_path(article) %></td>
<td><%= link_to 'Edit', edit_article_path(article) %></td>
<td><%= link_to 'Destroy', article_path(article),
method: :delete,
data: { confirm: 'Are you sure?' } %></td>
</tr>
<% end %>
</table>


Just not sure what it can be. Please advise. I will supply more code if needed.

4 Answers
4

The answer will be in your routes.rb and in the URL you are trying to call.

The URL is probably /comment/123, and the routes.rb likely has something like get 'comment/:id' => 'comment#show' in it (or a resource statement for comments).

/comment/123

get 'comment/:id' => 'comment#show'

resource

So rails tries to show the page for a comment and you did not implement the function. The error message is saying exactly what it needs to say (you do indeed not have a .show method in your CommentsController).

.show

CommentsController

If my guesses were not correct, then please post your routes.rb and the URL you are requesting.

You can add

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


to your comments_controller.rb

comments_controller.rb

Actually these codes are identical to those in the def destroy

def destroy

I've been working through the same tutorial, and just today ran into the exact same issue as the original poster.

I didn't notice exactly when it started, but it seemed to have started somewhere in section 6, 7 or 8 (adding comments to blog, refactoring, or adding deletion of comments).

Furthermore, clicking links within the app (i.e. the 'Back' link) would spawn a new tab. Likewise, when clicking the 'Destroy' link, the browser's confirmation dialog would appear over the current tab (correct behavior), but at the same time a new browser tab would appear (incorrect) - I think this new tab behavior (a type of 'show'ing of the comment that the user is in process of deciding whether to go ahead and destroy) is what was causing the error.

After finishing the tutorial (one more section, basic authentication), I quit & re-launched Chrome, and then also quit & restarted the server (ctrl-c, then bin/rails server).

After doing this, all is well. Both the spawning extra tab behavior, as well as the spurious show action being triggered (thus causing the error) - when the destroy confirmation sheet appears - have stopped.

So it seems that this problem was simply some spurious noise - perhaps caused by something that's changed (in the rails environment?) between the time the tutorial was originally written, and when the original poster ran into this behavior (and still persisting today, July '18, with rails 5.2).

Update: As I mentioned earlier you dont have show method in your CommentsController so you wont be able to visit the show page for any comment.

show

CommentsController

show

comment

As you said you are trying to visit this url: localhost:3000/articles/2/comments/1 which is the show page for comment having id: 1 and the routes(resources :comments) is trying to take it to show action. Hence the error rightly thrown show could not be found for CommentsController.

localhost:3000/articles/2/comments/1

comment

id:

resources :comments

show

show could not be found for CommentsController

Please remove the url from your browser and try visiting again the article show page. It will work.

article

show

show

CommentsController

article_path(@article)

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