Simple IP Geolocation Serive

config.ru

require 'bundler/inline'
require 'json'

gemfile do
  source 'https://rubygems.org'
  gem 'sliver'
  gem 'maxminddb'
  gem 'rack'
  gem 'byebug'
end

class IPLookupAction
  include Sliver::Action
  DB = MaxMindDB.new('./GeoLite2-City.mmdb')
  
  def call
    result = DB.lookup(ip)
    response.headers['Content-Type'] = 'application/json'
    not_found unless result.found?

    response.status = 200
    response.body = [JSON.generate(result.to_hash)]
  end
  
  private

  def not_found
    response.status = 404
    response.body = ['{}']
  end
  
  def ip
    self.request.params['ip'] || '255.255.255.255'
  end
end

app = Sliver::API.new do |api|
  api.connect :get, '/lookup', IPLookupAction
end

run app