NoMethodError in Posts#show error in section 6.4 of RailsGuides

Question

I am trying to follow the RailsGuides, http://edgeguides.rubyonrails.org/getting_started.html

Now, in section 6.4 where I am supposed to be able to add comments in my blog site, I am encountering this error:

NoMethodError in Posts#show
Showing C:/Sites/blog/app/views/posts/show.html.erb where line #12 raised: </br>
undefined method `comments' for #<Post:0x3a99668

below is the snippet in my show.html.erb

<h2>Add a comment:</h2>
<%= form_for([@post, @post.comments.build]) do |f| %>
 <p>
   <%= f.label :commenter %><br>
   <%= f.text_field :commenter %>

Below is the snippet for my comments controller:

class CommentsController < ApplicationController  
  def create
    @post = Post.find(params[:post_id])
    @comment = @post.comments.create(comment_params)
    redirect_to post_path(@post)
  end

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

Below is my Posts controller:

class PostsController < ApplicationController
def new
     @post = Post.new
end

def create
    @post = Post.new(params[:post].permit(:title, :text))

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

def show
    @post = Post.find(params[:id])
end

def index
    @posts = Post.all
end

def edit
    @post = Post.find(params[:id])
end

def update
    @post = Post.find(params[:id])

    if @post.update(params[:post].permit(:title, :text))
        redirect_to @post
    else
        render 'edit'
    end
 end

 def destroy
      @post = Post.find(params[:id])
      @post.destroy

      redirect_to posts_path
     end

private
  def post_params
    params.require(:post).permit(:title, :text)
  end
end

Please help me thanks.

-aguds

Answer 1

It's saying

"line #12 raised: undefined method `comments' for #< Post:0x3a99668 >"

That means in line 12 of your show.html.erb you are calling comments method on an object of Post, but that method is not defined.

So you need to check in your Post class that following relation is there.

app/models/post.rb

has_many :comments

The server needs to restarted once you add a new Model. (You added Comment.)

The general rule of thumb here is making changes to anything outside of app/ or config/routes.rb will require a restart.

Refer: When do I need to restart server in Rails?