text: ## Shorty
  ## Copyright 2012 Andrea Stagi
  ## See LICENSE
  
  ## @url git.io
  class Github(Service):
  
      def shrink(self, bigurl):
          gitio_pattern = 'http(s)?://((gist|raw|develop(er)?)\.)?github\.com'
          gitio_re = re.compile(gitio_pattern)
          if not gitio_re.search(bigurl):
              raise ShortyError('URL must match %s' % gitio_pattern)
          resp = request('http://git.io', post_data="url=%s" % bigurl)
          for header in resp.info().headers:
              if header.startswith("Location:"):
                  return header[10:].strip('\n\r')
          raise ShortyError('Failed to shrink url')
  