opinion-export.rb

#!/usr/bin/env ruby

require 'tempfile'
require 'open-uri'

# Settings
SUBDOMAIN       = "mypodcast"
DOWNLOAD_DIR    = "downloads"

# Opinion urls
PODCAST_URL     = "http://#{SUBDOMAIN}.madewithopinion.com"
FEED_URL        = "http://madewithopinion.com/feeds/#{SUBDOMAIN}/rss/"

# New urls
NEW_FEED_FILE   = "feed.rss"
NEW_ASSETS_URL  = "https://my-podcast.s3.amazonaws.com/assets"
NEW_PODCAST_URL = "http://my-domain.se/my-podcast"
NEW_FEED_URL    = "https://my-podcast.s3.amazonaws.com/feed.rss"

MATCH_ASSETS_RE = %r{
  (
  https?://
  [^"< ]+?/
  ([^/]+
  \.(?:m4a|jpg)
  ))
}x

def create_download_dir
  puts "Creating download dir"
  Dir.mkdir(File.join(__dir__, DOWNLOAD_DIR))
rescue Errno::EEXIST
  # All good
end

def download_assets(contents)
  urls = contents.scan(MATCH_ASSETS_RE).to_a.map { |e| e[0] }.join("\n")
  file = Tempfile.new('urls')

  begin
    file.write(urls)
    puts "Downloading all audio and image files. This might take a while…"
    puts "You can watch the progress using the \`watch\` command in another Terminal window, like:"
    puts "\`watch 'ls #{DOWNLOAD_DIR} | wc -l\`"
    Dir.chdir(DOWNLOAD_DIR) do
      `xargs -P 10 -n 1 curl -sOL < #{file.path}`
    end
    puts "Done, all downloaded"
  ensure
    file.close
    file.unlink
  end
end

def create_new_feed_file(contents)
  new_feed = contents
    .sub(FEED_URL, NEW_FEED_URL)
    .gsub(PODCAST_URL, NEW_PODCAST_URL)
    .gsub(MATCH_ASSETS_RE, NEW_ASSETS_URL + '/\2')

  puts "Writing new feed file"
  File.write(NEW_FEED_FILE, new_feed)
end

open(FEED_URL) do |f|
  contents = f.read()
  create_download_dir()
  download_assets(contents)
  create_new_feed_file(contents)
end

puts "Done"