Create an Epub of Works from Pottermore

potter.rb

require 'uri'
require 'erb'
require 'nokogiri'
require 'rpub'
require 'open-uri'

module Potter
  class Fetcher
    SITEMAP_URL = "https://www.pottermore.com/sitemap.xml"
    URL_MATCHER = /.*\/writing-by-jk-rowling\/(.+)/
    
    attr_reader :pages
    
    def fetch
      @pages = []
      doc = Nokogiri::HTML(open(SITEMAP_URL).read)
      puts "Fetching writing by JK Rowling"
      urls = doc.css('url loc').each do |url|
        next unless url.text =~ URL_MATCHER
        process(url.text)
      end
    end
    
    private
    
    def process(url)
      print '.'
      doc = Nokogiri::HTML(open(url).read)
      title = doc.css('h1').text
      body = doc.css(".jkr-writing-artefact__text").inner_html
      pages << { 
        url: url, title: title, body: body, doc: doc 
      }
    end
  end
  
  class Writer
    attr_reader :pages
  
    def initialize(pages)
      @pages = pages
               .select { |page| page[:body].to_s.length.nonzero? }
               .sort_by { |page| page[:title] }
    end
  
    def to_epub
      page_template = File.read('templates/page.md.erb')
      pages.each_with_index do |page, chapter|
        b = binding
        markdown = ERB.new(page_template).result(b)
        filename = "epub/#{chapter.to_s.rjust(5, '0')}.md"
        
        page[:body].gsub!(/></, ">\n\n<")
        File.open(filename, 'w') { |f| f.write(markdown) }
      end
  
      Dir.chdir('epub') do
        `rpub complie`
        `rm *.md`
        `mv *.epub ..`
      end
    end
  end
end

fetcher = Potter::Fetcher.new
fetcher.fetch
writer = Potter::Writer.new(fetcher.pages)
writer.to_epub