Question

I have never seen this error message before

undefined method `new' for Book:Module

and was wondering if anyone knew why i am getting it, my first thought is naming conventions but am unsure

I have a module

  module Book::BookFinder

  BOOK_URL = 'https://itunes.apple.com/lookup?isbn='

  def book_search(search)
  response = HTTParty.get(BOOK_URL + "#{search}", :headers => { 'Content-Type' => 'application/json', 'Accept' => 'application/json' })
 results = JSON.parse(response.body)["results"]
end

end

and then include it within my controller

 class BookController < ApplicationController
 before_filter :authenticate_admin_user!
 include Book::BookFinder


 def results
 results = book_search(params[:search])
 @results = results
 @book = Book.new
 @book.author = results[0]["artistName"]

end

def create
@book = Book.new(params[:book])
 if @book.save
redirect_to @book, notice: 'Book was successfully saved'
 else
render action:new
end
end
end

has anyone come across this before and know how to fix it?

Thanks

Answer 1

The issue comes from your use of Book.new.

Book is a Module (Book::BookFinder) and that can’t be instanced.

The Methods inside Book::BookFinder are now mixed into your controller and any methods in Book::BookFinder can be called directly on the controller without having to instance Book::BookFinder.

If you really want this to be a object use class instead of Module.

Update:
You obviously can’t just replace module with class.
But if you want to have a object Book that you can new and set properties on you need to write a class for that (and remove the include Book::BookFinder you now used for the Module.

A sample calss would look like this:

class Book
  def initialize
    # put constructor logic here
  end

  def some_method
    # methods that can be called on the instance
    # eg:
    # @book = Book.new
    # @book.some_method
  end

  # defines a get/set property
  attr_accessor :author
  # allows assignment of the author property
end

Hope this helps, but I strongly suggest you check out some tutorials on Ruby classes and how these things work.