import requests, re, json
  get_captions = lambda content: [post['caption'] for post in content['response']['posts'] if 'caption' in post]
  get_domains = lambda captions: map(lambda caption: re.sub('<.*?>', '', caption.split('</p>')[0]), captions)

  def process(url):
    offset = 0
    domains = []
    while True:
      resp = requests.get(url.format(offset))
      if resp.status_code == 404:
        return domains
      domains.extend(get_domains(get_captions(json.loads(resp.content))))
      offset += 20

  
  domains = process('http://api.tumblr.com/v2/blog/plaintextoffenders.com/posts?notes_info=true&api_key=<mykey>&offset={0}')
  with open('/tmp/domains', 'w') as dfile:
    dfile.write('\n'.join(domains))