Swapping multi-bitrate HLS playlists with a single sub-playlist

changer.rb

require 'nokogiri'
require 'open-uri'
require 'httparty'
require 'pathname'

class CategoryItem
  attr_accessor :title, :description, :feed, :element
  
  def initialize(node)
    @element     = node
    @title       = node[:title]
    @description = node[:description]
    @feed        = node[:feed]
  end  
end

class Category
  attr_accessor :title, :description, :items, :sd_image, :hd_image, :element
  
  def initialize(node)
    @element     = node
    @title       = node[:title]
    @description = node[:description]
    @sd_image = node[:sd_image]
    @hd_image = node[:hd_image]
    
    @items = []
    node.children.each do |child|
      @items << CategoryItem.new(child) if child.element?
    end  
  end  
end  

class Playlist
  attr_reader :url, :file, :playlists
  
  def initialize(url)
    @file = HTTParty.get(url).body
    
    @playlists = []
    parse
  end
  
  def parse
    @file.each_line do |line|
      @playlists << line.strip if has_playlist?(line)
    end  
  end
  
  private
  
  def has_playlist?(str)
    true if /.m3u8/.match(str)
  end  
end  

class FeedItem
  attr_accessor :stream_url, :title, :description, :element, :playlist
  
  def initialize(node)
    @element = node
    
    @title       = node.at_xpath("title").content
    @description = node.at_xpath("description").content 
    @stream_url  = node.at_xpath("*/streamUrl").content
    @playlist    = Playlist.new(@stream_url)
  end  
  
  def playlists
    playlist.playlists
  end  
end  

class Feed
  attr_accessor :items, :element, :filename
  
  def initialize(node, filename)
    @element  = node
    @filename = filename
    
    @items = []    
    node.xpath("//item").each do |item|
      @items << FeedItem.new(item)
    end  
  end  
end  


# Original Feed Url
url = ""

# Where to save the modified files
output_path = ""

categories = []
feeds      = []

doc =  Nokogiri::XML(open(url))
doc.xpath("//category").each do |category|
  categories << Category.new(category)
end

categories.each do |cat|
  cat.items.each do |item|
    
    feeds << Feed.new(Nokogiri::XML(open(item.feed)), Pathname.new(item.feed).basename.to_s)
  end  
end  
  
feeds.each do |feed|
  feed.items.each do |item|
    item.element.at_xpath("*/streamUrl").content = item.playlists[0]
  end  
  
  puts "Saving #{feed.filename}"
  File.open(File.join(output_path, feed.filename), "w") do |f|
    f << feed.element.to_xml
  end  
end