Get Korean Pharmacy with OpenAPI

get_pharmacy.rb

require 'json'
require 'rest-client'

url = 'http://openapi.e-gen.or.kr/openapi/service/rest/ErmctInsttInfoInqireService/getParmacyListInfoInqire'.freeze
key = 'Your Secret key'
params = {pageNo: 1, numOfRows: 100, ServiceKey: key}

data = RestClient.get(url, {params: params, accept: :json})
total_count = (JSON.parse(data.body)['response']['body']['totalCount'] / 100.to_f).ceil
total_data = []

total_count.times do |count|
  params = {pageNo: count, numOfRows: 100, ServiceKey: key}
  data = RestClient.get(url, {params: params, accept: :json})
  total_data.concat(JSON.parse(data.body)['response']['body']['items']['item'])
  print "...#{count}/#{total_count}\r"
  $stdout.flush
end

File.write('night-pharmacy.json', total_data.to_json.gsub('\"', ''))

Your generated secret key will be encoded UTF-8. So before use it, you must decode your secret key or server can not recognize.