Easy to use Ruby script to register and authorize new domains on Let's Encrypt and getting certificates for them. Call 'ruby le-new.rb' and follow the instructions. Install OpenSSL and the ACMEClient gem before!

le-cert.rb

#!/usr/bin/env ruby

begin
	require 'acme-client'
rescue LoadError
	abort 'MISSING GEM! You haven\'t installed the ACME client. Install the gem with the command \'gem install acme-client\'.'
end

require 'openssl'
require 'resolv'

print 'Path to Let\'s Encrypt private key (path/to/key.pem): '
private_key_path = gets.chomp
unregistered_private_key = private_key_path == ''

session_dir = Time.now.to_i.to_s
Dir.mkdir session_dir

endpoint = 'https://acme-v01.api.letsencrypt.org/' # 'https://acme-staging.api.letsencrypt.org/'
private_key = begin
	if private_key_path != ''
		OpenSSL::PKey::RSA.new File.read(private_key_path)
	else
		key = OpenSSL::PKey::RSA.new 4096
		File.write "#{session_dir}/client_key.pem", key.to_pem
		key
	end
end
client = Acme::Client.new(private_key: private_key, endpoint: endpoint)

if unregistered_private_key
	email = ''

	while email == ''
		print 'Your email address: '
		email = gets.chomp

		if email == ''
			puts 'Email address is required!'
		end
	end

	registration = client.register(contact: "mailto:#{email}")

	agree_status = ''
	
	while true
		print 'Agree service terms (Y/n) ? '
		agree_status = gets.chomp

		break if agree_status == 'Y' || agree_status == 'y' || agree_status == 'N' || agree_status == 'n'

		puts 'Invalid input!'
	end

	if agree_status == 'Y' || agree_status == 'y'
		registration.agree_terms
	else
		raise
	end
end

domains = {}

puts 'Enter your domains you want to register. Leave empty if you are finished.'

while true
	print 'Domain: '
	domain = gets.chomp

	break if domain == ''

	unless unregistered_private_key
		authorization_status = ''

		while true
			print 'Are you already authorized for this key (Y/n)? '
			authorization_status = gets.chomp

			break if authorization_status == 'Y' || authorization_status == 'y' || authorization_status == 'N' || authorization_status == 'n'

			puts 'Invalid input!'
		end

		domains[domain] = { authorized: authorization_status == 'Y' || authorization_status == 'y' }
	else
		domains[domain] = { authorized: false }
	end
end

domains.each do |domain, value|
	unless value[:authorized]
		authorization = client.authorize domain: domain
		challenge  = authorization.dns01

		domains[domain][:authorization] = authorization
		domains[domain][:challenge] = challenge
	end
end





puts
puts 'Add the following DNS records to your domain names.'
puts

domains.each do |domain, value|
	next if value[:authorized]

	authorization = value[:authorization]
	challenge = value[:challenge]

	puts "==============================================="
	puts
	puts "Domain: #{domain}"
	puts
	puts 'DNS Record:'
	puts
	puts "Name:    #{challenge.record_name}.#{domain}"
	puts "Type:    #{challenge.record_type}"
	puts "Content: #{challenge.record_content}"
	puts "TTL:     Shortest possible time-to-live"
	puts
end

general_dns = Resolv::DNS.new(nameserver: ['8.8.8.8', '8.8.4.4'])

puts "It's automatically checking if you have set the records and continues when you are authorized for all domains..."

dns_records_found = false

while not dns_records_found

	domains.each do |domain, value|
		next if value[:authorized]
		next if value[:dns_record_found]

		begin
			dns_challenge = general_dns.getresource("_acme-challenge.#{domain}", Resolv::DNS::Resource::IN::TXT)
		rescue Resolv::ResolvError
			next
		end

		domains[domain][:dns_record_found] = dns_challenge.data == value[:challenge].record_content

		if domains[domain][:dns_record_found]
			puts "Record for domain \"#{domain}\" found."
		end
	end

	dns_records_found = true

	domains.each do |domain, value|
		dns_records_found = false unless value[:dns_record_found]
	end

	break if dns_records_found

	sleep(2)

end

puts
puts "Let's Encrypt verification:"
puts "==========================="
domains.each do |domain, value|
	next if value[:authorized]

	authorization = value[:authorization]
	challenge = value[:challenge]

	challenge.request_verification
	sleep 1

	puts "#{authorization.domain} : #{challenge.verify_status}"
end







csr = Acme::Client::CertificateRequest.new(names: domains.keys)
certificate = client.new_certificate(csr)

File.write("#{session_dir}/privkey.pem", certificate.request.private_key.to_pem)
File.write("#{session_dir}/cert.pem", certificate.to_pem)
File.write("#{session_dir}/chain.pem", certificate.chain_to_pem)
File.write("#{session_dir}/fullchain.pem", certificate.fullchain_to_pem)

puts
puts 'Here is your new certificate:'
puts
puts 'Private Key:'
puts
puts certificate.request.private_key.to_pem
puts
puts 'Certificate:'
puts
puts certificate.to_pem
puts
puts 'Chain:'
puts
puts certificate.chain_to_pem
puts
puts
puts
puts "You will find the certificates also in the session directory. This is in the same path as the script and the folder has the name #{session_dir}."
puts
puts 'Have fun with your new certificates ^^.'
puts