Unpermitted parameters: author - ruby-on-rails

Question

My requirements
Basically I'm adding books to a database, and I want to store the Author in a separate table. So I have a table called authors which is referenced by the table books.
I want to create a rails form for adding a book, and I'd like it to be just a simple form for Author, Title, Publisher etc, and if it finds the author already in the authors table then it should just reference that record, and if it isn't in the authors table then it should add a new record and reference it.
while storing values i am getting in log file
Unpermitted parameters: author
Processing by BooksController#create as HTML
Parameters: {"utf8"=>"✓", "authenticity_token"=>"8sxeOVMVJucl5nN+kMpSaT1cB1yDPnk5gfKElWPiT5k=", "book"=>{"book_name"=>"life ", "price"=>"20", "author"=>{"author_name"=>"swamy", "title"=>"LIFE", "publisher"=>"cta"}}, "commit"=>"Submit"}
swamy
LIFE
cta
Author Load (1.6ms) SELECT "authors".* FROM "authors" WHERE "authors"."author_name" = 'swamy' AND "authors"."title" = 'LIFE' AND "authors"."publisher" = 'cta' LIMIT 1
(0.6ms) BEGIN
SQL (25.2ms) INSERT INTO "authors" ("author_name", "created_at", "publisher", "title", "updated_at") VALUES ($1, $2, $3, $4, $5) RETURNING "id" [["author_name", "swamy"], ["created_at", "2015-07-01 03:53:22.712401"], ["publisher", "cta"], ["title", "LIFE"], ["updated_at", "2015-07-01 03:53:22.712401"]]
(16.8ms) COMMIT
Unpermitted parameters: author
(0.7ms) BEGIN
SQL (1.0ms) INSERT INTO "books" ("Author_id", "book_name", "created_at", "price", "updated_at") VALUES ($1, $2, $3, $4, $5) RETURNING "id" [["Author_id", 8], ["book_name", "life "], ["created_at", "2015-07-01 03:53:22.865106"], ["price", 20], ["updated_at", "2015-07-01 03:53:22.865106"]]
(22.4ms) COMMIT
my code
books_Controller
class BooksController < ApplicationController
def new
end
def create
#a=params[:author_name]
puts #a
b=params[:book][:author][:author_name]
puts b
# #c = #b.authors
# #d = #c.author_name
c=params[:book][:author][:title]
d=params[:book][:author][:publisher]
puts c
puts d
#author = Author.find_or_create_by(author_name: b,title: c, publisher: d)
#book = Book.new(books_params)
#book.Author = #author
#book.save
redirect_to root_url
end
private
def books_params
params.require(:book).permit(:book_name, :price,:author_attributes => [:author_name, :title, :publisher])
end
end
model
class Author < ActiveRecord::Base
end
class Book < ActiveRecord::Base
belongs_to :Author
accepts_nested_attributes_for :Author
# def author_name=(author_name)
# self.author = Author.find_or_create_by_name author_name
#end
end
view
books.html.erb
<%= form_for Book.new do |f| %>
<p>
<%= f.label :book_name %><br />
<%= f.text_field :book_name %>
</p>
<p>
<%= f.label :price %><br />
<%= f.text_field :price %>
</p>
<%= f.fields_for :author do |b| %>
<p>
<%= b.label :author_name%><br />
<%= b.text_field :author_name %>
</p>
<p>
<%= b.label :title%><br />
<%= b.text_field :title %>
</p>
<p>
<%= b.label :publisher%><br />
<%= b.text_field :publisher%>
</p>
<% end %>
<p><%= f.submit "Submit" %></p>
<% end %>
~
Hi sir i am new to rails i know it looks simple but i unable it find solution
~
~

Answer 1

That is because your books_params has author_attributes when it should be author based on your parameters.
This should work:
def books_params
params.require(:book).permit(:book_name, :price, :author => [:author_name, :title, :publisher])
end

Answer 2

Your code is full of errors. Follow my changes.
#book.rb
class Book < ActiveRecord::Base
belongs_to :author
accepts_nested_attributes_for :author
end
#books_controller.rb
def new
#book = Book.new
#book.build_author
end
def create
#book = Book.new(books_params)
if #book.save
redirect_to root_url
end
end
Finally in your form change <%= form_for Book.new do |f| %> to <%= form_for #book do |f| %>

Answer 3

Change authore to author_attributes in view file, like this.
<%= f.fields_for :author_attributes do |b| %>
<p>
<%= b.label :author_name%><br />
<%= b.text_field :author_name %>
</p>
Also change respectively in controller also. I think, this much is enough.
def create
#book = Book.new(books_params)
#book.save
redirect_to root_url
end

Answer 4

I will Suggested you just debug your code
def books_params
byebug
params.require(:book).permit(:book_name, :price, :author => [:author_name, :title, :publisher])
end
1: check your requested params
2: kindly check params.require(:book)
Requested parameter would be like
Parameters: {"utf8"=>"✓", "authenticity_token"=>"8sxeOVMVJucl5nN+kMpSaT1cB1yDPnk5gfKElWPiT5k=", "book"=>{"book_name"=>"life ", "price"=>"20", "author_"=>{"author_name"=>"swamy", "title"=>"LIFE", "publisher"=>"cta"}}, "commit"=>"Submit"}
check with this link NestedAttributes
Your controller would be this
class BooksController < ApplicationController
def new
end
def create
#author = Author.create(params[:book])
redirect_to root_url
end
private
def books_params
params.require(:book).permit(:book_name, :price,:author_attributes => [:author_name, :title, :publisher])
end
end