CloudKit server-to-server example in Ruby

CloudKit.rb

#!/usr/bin/env ruby

# CloudKit public database connection with server-to-server
# See https://developer.apple.com/library/archive/documentation/DataManagement/Conceptual/CloudKitWebServicesReference/SettingUpWebServices.html#//apple_ref/doc/uid/TP40015240-CH24-SW6

require 'time'
require 'openssl'
require 'digest'
require 'json'
require 'base64'
require 'uri'
require 'net/http'

# class Cloudkit

	CK_PEM_STRING = """
-----BEGIN EC PRIVATE KEY-----
YOUR PRIVATE KEY
-----END EC PRIVATE KEY-----
	"""
	CK_SERVICE_BASE = "https://api.apple-cloudkit.com"
	CK_KEY_ID = "YOUR_CLOUDKIT_KEY_ID"

	def signature_for_request(body_json, url, iso8601_date)
		puts "body_json: #{body_json}"
		body_sha_hash = Digest::SHA256.digest body_json

		payload_for_signature = [iso8601_date, Base64.strict_encode64(body_sha_hash), url].join(':')
		puts "payload_for_signature: #{payload_for_signature}"

		OpenSSL::PKey::EC.send(:alias_method, :private?, :private_key?)

		ec = OpenSSL::PKey::EC.new(CK_PEM_STRING)
		puts "ec: #{ec}"
		digest = OpenSSL::Digest::SHA256.new
		puts "digest: #{digest}"
		signature = ec.sign(digest, payload_for_signature)
		puts "signature: #{signature}"
		base64_signature = Base64.strict_encode64(signature)
		puts "base64_signature: #{base64_signature}"

		return base64_signature
	end

	def perform_request_for(body, url, iso8601_date)
		body = body.to_s
		signature = self.signature_for_request(body, url, iso8601_date)

		uri = URI.parse(CK_SERVICE_BASE + url)

		header = {
			"Content-Type": "text/plain",
			"X-Apple-CloudKit-Request-KeyID": CK_KEY_ID,
			"X-Apple-CloudKit-Request-ISO8601Date": iso8601_date,
			"X-Apple-CloudKit-Request-SignatureV1": signature
		}

		# Create HTTP objects
		http = Net::HTTP.new(uri.host, uri.port)
		http.use_ssl = true

		request = Net::HTTP::Post.new(uri.request_uri, header)
		request.body = body

		# Send the request
		response = http.request(request)

		return response
	end

# end


t = Time.now.utc.iso8601

# The path to the endpoint you want to query
# YOUR_CONTAINER_NAME = e.g. iCloud.com.your_app
# Swap development for production as needed
url = "/database/1/YOUR_CONTAINER_NAME/development/public/records/query"
body = """
{
	\"zoneID\": {
		\"zoneName\": \"_defaultZone\"
	},
	\"query\": {
		\"recordType\": \"CD_YourRecordType\"
	}
}
"""

puts perform_request_for(body, url, t).body