First argument in form cannot contain nil or be empty - ruby-on-rails

Question

I receive this error with my Book form in rails:
First argument in form cannot contain nil or be empty
Form
<%= form_for #book, html: { multipart: true } do |f| %>
<% if #book.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(#book.errors.count, "error") %> prohibited this book from being saved:</h2>
<ul>
<% #book.errors.full_messages.each do |message| %>
<li><%= message %></li>
<% end %>
</ul>
</div>
<% end %>
<div class="field">
<%= f.label :title %><br>
<%= f.text_field :title %>
</div>
<div class="field">
<%= f.label :author %><br>
<%= f.text_field :author %>
</div>
<div class="field">
<%= f.label :language %><br>
<%= f.text_field :language %>
</div>
<div class="field">
<%= f.label :year %><br>
<%= f.text_field :year %>
</div>
<div class="field">
<%= f.label :description %><br>
<%= f.text_area :description %>
</div>
<div class="field">
<%= f.label :total_pages %><br>
<%= f.text_field :total_pages %>
</div>
<div class="field">
<%= f.label :rating %><br>
<%= f.text_field :rating %>
</div>
<div class="field">
<%= f.label :image %><br>
<%= f.file_field :image %>
</div>
<div class="actions">
<%= f.submit %>
</div>
<% end %>
Controller
class BooksController < ApplicationController
before_action :set_book, only: [:show, :edit, :update, :destroy]
before_action :authenticate_user!, except: [:index, :show]
def search
if params[:search].present?
#books = Book.search(params[:search])
else
#books = Book.all
end
end
def index
#books = Book.all
end
def show
#reviews = Review.where(book_id: #book.id).order("created_at DESC")
if #reviews.blank?
#avg_review = 0
else
#avg_review = #reviews.average(:rating).round(2)
end
end
end
def new
#book = current_user.books.build
end
def edit
end
def create
#book = current_user.books.build(book_params)
respond_to do |format|
if #book.save
format.html { redirect_to #book, notice: 'Book was successfully created.' }
format.json { render :show, status: :created, location: #book }
else
format.html { render :new }
format.json { render json: #book.errors, status: :unprocessable_entity }
end
end
end
def update
respond_to do |format|
if #book.update(book_params)
format.html { redirect_to #book, notice: 'Book was successfully updated.' }
format.json { render :show, status: :ok, location: #book }
else
format.html { render :edit }
format.json { render json: #book.errors, status: :unprocessable_entity }
end
end
end
def destroy
#book.destroy
respond_to do |format|
format.html { redirect_to books_url, notice: 'Book was successfully destroyed.' }
format.json { head :no_content }
end
end
private
def set_book
#book = Book.find(params[:id])
end
def book_params
params.require(:book).permit(:title, :author, :language, :year, :description, :total_pages, :rating, :image)
end
I got related errors, but none of the solutions seems to fit my particular issue. Any clues to what could be causing this?

Answer 1

You're getting the error because #book is nil.
Make sure that you have initialized #book using #book = Book.new in the corresponding controller action so that #book is available to the view containing the form.

Answer 2

initialized #book = Book.new in the controller action