gist_quine.rb

require 'net/http'
require 'json'

# a simple wrapper to do an HTTP GET
def fetch_uri(uri, limit = 10)
  uri = URI(uri)
  request = Net::HTTP::Get.new(uri.request_uri)

  http = Net::HTTP.new(uri.hostname, uri.port)
  if uri.scheme == 'https'
    http.use_ssl = true
    http.verify_mode = OpenSSL::SSL::VERIFY_PEER
  end

  response = http.request(request)

  if response.is_a?(Net::HTTPRedirection) && limit > 0
    location = response['location']
    fetch_uri(location, limit - 1)
  else
    response
  end
end

# GETs the URI and returns a Ruby hash.
def fetch_json(uri)
  result = fetch_uri(uri)
  JSON.load(result.body)
end

def parse_uri_template(uri, thing)
  uri.gsub /\{(\/)?.*\}/, "\\1#{thing}"
end

# Let's begin!

json = fetch_json('https://api.github.com/')

# Could be cleaner!

gist_uri = parse_uri_template(json["gists_url"], "5283510")
gist_json = fetch_json(gist_uri)
gist_filename = gist_json["files"].keys.first
gist_raw_uri = gist_json["files"][gist_filename]["raw_url"]
gist = fetch_uri(gist_raw_uri)

# Quine!

puts gist.body