Question

So I’m trying to create a form for users to leave a review about a movie but Rails keeps throwing an undefined method error at me. My app allows users to review movies. So I want the form to allow the user to create a review in the context of that movie. My code is below, any help would be much appreciated. My only confusion is, I’m not sure whether I should nest the resources or I’m just using specifying the wrong value for form_for

My routes file looks like this:

  resources :users
  resources :movies
  resources :reviews
  resources :sessions, only: [:new, :create, :destroy]

I have a Reviews controller which looks like this:

class ReviewsController < ApplicationController

    def create
        movie_id = params[:review].delete(:movie_id)

        @review = Review.new(params[:review])
        @review.movie_id = movie_id

        @review.save

        redirect_to movie_path(@review.movie)
    end
end

And my form looks like this:

<h2>Leave a Review</h2>

<%= form_for(@review) do |f| %>
  <%= f.hidden_field :movie_id %>
  <div class="field">
    <%= f.text_area :content, placeholder: "Write a new review..." %>
  </div>
  <%= f.submit "Submit", class: "btn btn-large btn-primary" %>
<% end %>

I have three models:

User:

class User < ActiveRecord::Base

  has_secure_password
  has_many :reviews, dependent: :destroy
  has_many :movies, through: :reviews

end

Movie:

class Movie < ActiveRecord::Base

  has_many :reviews
  has_many :users, through: :reviews


end

Review:

class Review < ActiveRecord::Base

  attr_accessible :content, :movie_id
  belongs_to :user
  belongs_to :anime

end

Here is the error:

NoMethodError in Movies#show

Showing /Users/david/Sites/Rails/Chirp/app/views/movies/show.html.erb where line #32 raised:

undefined method `model_name' for NilClass:Class
Extracted source (around line #32):

29: 
30: <h2>Leave a Review</h2>
31: 
32: <%= form_for(@review) do |f| %>
33:   <%= f.hidden_field :movie_id %>
34:   <div class="field">
35:     <%= f.text_area :content, placeholder: "Write a new review..." %>

Answer 1

Your @review instance variable is actually a Movie. @review.movie will be undefined

EDIT

Ok, you edited your question to fix your @review variable.

So what’s happening now is that your Review controller sets up the @review instance variable, and then does a redirects to Movies#show. The redirect request effectively throws out all the instance variables you setup in your Review controller.

So from the point of view of Movies#show, @review doesn’t exist.

Either share your code for your Movies controller show action so we can see what’s going on, or just try redefining @review in Movies#show

@movie = Movie.find params[:id]
@review = current_user.reviews.build(movie: @movie)