Converts JSON to XML. Can use either filenames passed as arguments, or operates on standard input. Uses the 'xmlsimple' library for XML output.

json2xml.rb

require 'json'
require 'xmlsimple'

json_file, xml_file = ARGV

json_text = nil

unless json_file.nil?
  if File.exist?(json_file)
    json_text = File.new(json_file, 'r').read
  else
    puts "File #{json_file} does not exist!"
    exit
  end
else
  json_text = $stdin.read
end

data = JSON.parse(json_text)

xml_text = XmlSimple.xml_out(data)

unless xml_file.nil?
  f = File.new(xml_file, 'w+')
  f.write(xml_text)
  f.close
else
  $stdout.puts xml_text
end