DJ Tiësto's podcast download/sync script

tiestoSync.rb

#!/usr/bin/ruby
#-------------------------------------------------------------------------------
# File:       tiestoSync.rb
# Purpose:    Syncs a directory of DJ Tiësto's podcasts with the current Web list
# Arguments:  [0] Directory containing podcast files to sync
# Returns:    N/A
# Example:    tiestoSync.rb ~/podcasts
# Author(s):  Abe Voelker (http://abevoelker.com)
# Created:    2011-01-09
# License:    Released into the public domain.
#-------------------------------------------------------------------------------

PODCAST_URL = 'http://www.radio538.nl/clublife/podcast.xml'

require 'net/http'
require 'rubygems'
require 'xmlsimple'

#Just a few checks for good measure
dir = ARGV[0]
if !File::exists?(dir) then
    $stderr.puts("'" + dir + "' doesn't exist!")
    exit
end
if !File::directory?(dir) then
    $stderr.puts("'" + dir + "' isn't a directory!!")
    exit
end
if !File::writable?(dir) then
    $stderr.puts("Directory '" + dir + "' isn't writable!")
    exit
end

xml_data = Net::HTTP.get_response(URI.parse(PODCAST_URL)).body
data = XmlSimple.xml_in(xml_data)

data['channel'][0]['item'].each do |item|
    podcast = item['enclosure'][0]['url']
    file = podcast.split("/").last
    
    puts "Checking for file '" + file + "'"
    if File::exists?(dir + '/' + file) then
        puts "Skipping existing file '" + file + "'"
    else
        puts "Downloading non-existent file '" + file + "'..."
        file = dir + '/' + file
        Net::HTTP.start(URI.parse(podcast).host) do |http|
            resp = http.get(podcast)
            open(file, "wb") do |file|
                puts "Writing file to disk..."
                file.write(resp.body)
            end
        end
    end
end