CODEWITHSUNDEEP
ruby-on-railsrubyruby-on-rails-4.2
Xeen
Xeen

Reputation: 7003

Ruby on Rails undefined method `title' for nil:NilClass

I have the following setup:

Product.rb

class Product < ActiveRecord::Base
  belongs_to :category
end

Category.rb

class Category < ActiveRecord::Base
  belongs_to :category
  has_many :categories
  has_many :products
end

categories_controller.rb

def show
end

private
  def set_category
    @category = Category.find(params[:id])
  end

  def category_params
    params.require(:category).permit(:title, :category_id)
  end

products_controller.rb

def product_params
   params.require(:product).permit(:title, :price, :text, :category_id, :avatar)
end

Category show

<% @category.products.each do |p| %>

   <article class="content-block">
      <h3><%= @p.title %></h3>
   </article>

<% end %>

And this returns the error in the title. What have I done wrong here?

Upvotes: 1

Views: 401

Answers (1)

Arup Rakshit
Arup Rakshit

Reputation: 118271

It should be :

<h3><%= p.title %></h3> # as, your block variable is p, not @p

NOT

<h3><%= @p.title %></h3>

One more suggestion, you could write your set_category method, as:

def set_category
  @category = Category.includes(:products).find(params[:id])
end

It will solve N + 1 problems using Eager Loading Associations technique.

Upvotes: 4

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