Download tags

Gemfile

source 'https://rubygems.org'

gem 'http'

Gemfile.lock

GEM
  remote: https://rubygems.org/
  specs:
    addressable (2.4.0)
    domain_name (0.5.20160128)
      unf (>= 0.0.5, < 1.0.0)
    http (1.0.2)
      addressable (~> 2.3)
      http-cookie (~> 1.0)
      http-form_data (~> 1.0.1)
      http_parser.rb (~> 0.6.0)
    http-cookie (1.0.2)
      domain_name (~> 0.5)
    http-form_data (1.0.1)
    http_parser.rb (0.6.0)
    unf (0.1.4)
      unf_ext
    unf_ext (0.0.7.2)

PLATFORMS
  ruby

DEPENDENCIES
  http

BUNDLED WITH
   1.11.2

get.rb

require 'http'

def get(url)
  # puts "Downloading: #{url}"
  JSON.parse(HTTP.get(url))
end

top_level = get('https://www.gov.uk/api/content/topic')

result = top_level.clone

result['links']['children'] = top_level['links']['children'].map do |not_expanded|
  second_level = get(not_expanded['api_url'])

  grand_children = second_level['links']['children'].map do |not_expanded|
    get(not_expanded['api_url'])
  end

  second_level['links']['children'] = grand_children
  second_level
end

puts JSON.pretty_generate(result)