Random Generation of Items from Existing Model - ruby-on-rails

Question

I am fairly new to RoR and trying to get a basic app to work - I have a 'books' model and a 'genre' model. I wish to create a page that randomly generates books of different genre's for a user to select.
I have created a 'random_book' controller, but am unsure on how to proceed with the random selection and display.
Any help/pointers would be appreciated.
Edit:
Here's the work I've been doing in the random_book model:
" load 'user.rb'
class random_book < ActiveRecord::Base
belongs_to :book
belongs_to :genre
def get_random_book
find(:all).sample(5)
end
"
Thank you.

Answer 1

Based on discussion
4 models
Book
Genre
UserBook
User
They will look something like this:
class User < ActiveRecord::Base
has_many :user_books
has_many :books, through: :user_books
end
class Genre < ActiveRecord::Base
has_many :books
def fetch_random_books(qty)
#you want to make sure you don't error out by requesting a sample of an empty list of books so check first. The qty argument lets you control the number of books for the search
unless self.books.empty?
self.books.limit(qty).sample
end
end
end
class Book < ActiveRecord::Base
belongs_to :genre
has_many :user_books
end
class UserBook < ActiveRecord::Base
belongs_to :book
end
I would most likely use a different route for the random book section, because it's not very url-friendly to say code-descriptive things like user_book.
There are 4 things to do
Create a new route to get a list of genre_ids that a user chooses.
Create an action that correlates to the route you created that renders a list of boos and adds those books to a users list
Create a form in a view (any view, like a sidebar in an existing books view, doesn't matter) this form will post the route and action you just made
Create a view to render the book list (the easy / DRY way is to add a few elements to the existing books index to let users know its a random generated list of books based on their genre pics)
Add the route
post "/random-books", to: "books#random_books", as: :random_books
Create the action in the books_controler
def random_books
if params[:genre_ids]
genres = Genre.where(id: params[:genre_ids])
#books = []
genres.each do |genre|
#books << genre.fetch_random_books(10)
end
else
#books = nil
end
respond_to do |format|
format.html { render action: :index }
end
end
Then create a form that makes a post request to the index action of the books_controller -- You can parse the form and update the UserBook model inside that action, and then display list of books all at the same time.
<%= form_tag(random_books_path, method: :post) do %>
<ul>
<% Genre.all.each do |genre| %>
<li>
<label class='genre-select'>
<%= check_box_tag 'genre_ids[]', genre.id -%>
<%= genre.name %>
</label>
</li>
<% end %>
</ul>
<%= submit_tag "Fetch Book List"%>
<% end %>
-- The last one I'm sure you can do, it returns a books object list so parse it however works best for you. In the controller action you can automatically add the ids for the books to the UserBook model by adding this inside the controller action:
#books.each{ |book| book.user_books.create(user: user)}