Adapter Pattern

google_books_adapter.rb

# How to think about the Single Responsibility Principle in your application...
# What part of your app has the responsibility of making the request to the API
# and turning the response into Ruby Objects & records in your database...?

# Not really the Models...
# ...And you may not want all the code that does this just intertwined within the logic of your app
# ... so where to put this code?


# That's what the Adapter Pattern is for.
# Make a class who's only responsibility is to get the data from the API
# and turn it into the format you want for your application

# Below is an example


module GoogleBooks

  class Adapter
    attr_reader :term

    BASE_URL = "www.googleapis.com/books/v1/volumes"

    def initialize(term = 'ruby programming')
      @term = term
    end

    def create_books_and_authors

      # make a request to the API
      response = RestClient.get("#{BASE_URL}?q=#{self.term}")
      data = JSON.parse(response.body)
      #iterate over all the books in that response
      data['items'].each do |book_data|
        
        book = Book.find_or_initialize_by(title: book_data['volumeInfo']['title'], description: book_data['volumeInfo']['description'])
        
        if  book_data['volumeInfo']['authors']
          author_name =  book_data['volumeInfo']['authors'].first
          author = Author.find_or_create_by(name: author_name)
        end
        
        # create and save the book objects and associated authors
        book.author = author
        book.save

      end

    end

  end


end


# The code above could be used in your application like so:

# puts "Welcome to the Library Searcher"
# puts "Please Enter a search term:"
# query = gets.chomp

# GoogleBooks::Adapter.new(query).create_books_and_authors


# Here is a great blogpost on the Adapter Pattern, though it's in the context of Ruby on Rails
# http://www.thegreatcodeadventure.com/rails-refactoring-part-i-the-adapter-pattern/
# Ignore the parts you don't know (the Controller) and focus on the parts about the refactoring