在Rails电子商务Web应用程序上评论ruby时出现错误400

Question

I'm actually making an ecommerce web app which has a User , Category , Book and Comment models. Everything is working nice, but when I try to comment in one of the book, it gives a 400 error. I really need you to help me out. https://github.com/felixpro/Book-app this is my repository.

This is my CommentsController

class CommentsController < ApplicationController

  before_action :authenticate_user!

  def create
    book = Book.find(params[:comment][:book_id])
    comment = book.comments.build(comment_params)
    comment.user = current_user
  ​
    if comment.save
      redirect_to book_path(@book)
    end
  end

  private

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

end

This is the comment view partial,

<% if signed_in? %>
  <div class="card bg-light new-comment">
    <div class="card-body">
      <p class="font-weight-bold">Deja tu comentario:</p>
      <%= form_for @book.comments.build do |f| %>
        <%= f.hidden_field :book_id, value: @book.id %>
        <div class="form-group">
          <%= f.text_area :body, rows: 4, class: "form-control" %>
        </div>
​
        <div class="text-right">
          <%= f.submit "Comentar", class: "btn btn-primary" %>
        </div>
      <% end %>
    </div>
  </div>
<% else %>
  <div class="card bg-light mt-5">
    <div class="card-body">
      <p class="card-text text-center lead"><%= link_to "Regístrate", new_user_registration_path %> o <%= link_to "Ingresa", new_user_session_path %> para comentar</p>
    </div>
  </div>
<% end %>

Here are the routes

Rails.application.routes.draw do
  devise_for :users
  root 'books#index'
   resources :books

   resources :comments, only: [:create]

 end

The error say

This is a pictures showing the error message

Answer 1

The error you mentioned is linked to the fact that you have a special invisible character (non-breaking space) at line 9 and 14 in your CommentsController. This is why you get the

NameError (undefined local variable or method `​' for ...)

This often happens when you hit an additional key at the same time you hit the space bar (cmd + space bar on MacOS). Delete those empty lines and type the enter key again to clear the character.

Then the other answer is right, you'll have have to update your book variable name.

Answer 2

You have referred to @book when the variable is a local book . Use @ at the beginning of the line 6:

@book = Book.find(params[:comment][:book_id])