Ruby DNS Check

dns_check.rb

require 'resolv'

class DnsCheck
  attr_reader :host
  def initialize(host)
    @host = host
  end

  def a
    @a ||= Resolv::DNS.new.getresources(host, Resolv::DNS::Resource::IN::A)
  end

  def a?
    a.any?
  end

  def mx
    @mx ||= Resolv::DNS.new.getresources(host, Resolv::DNS::Resource::IN::MX)
  end

  def mx?
    mx.any?
  end

  def ns
    @ns ||= Resolv::DNS.new.getresources(host, Resolv::DNS::Resource::IN::NS)
  end

  def ns?
    ns.any?
  end
end

test.rb

require 'testrocket'
require './dns_check'

!-> { 'It returns true / record sets for legit domains' }
+-> { DnsCheck.new('github.com').a? }
+-> { DnsCheck.new('github.com').a.any? }
+-> { DnsCheck.new('github.com').mx? }
+-> { DnsCheck.new('github.com').mx.any? }
+-> { DnsCheck.new('github.com').ns? }
+-> { DnsCheck.new('github.com').ns.any? }

!-> { 'It returns false / empty arrays for invalid domains' }
--> { DnsCheck.new('boomthisisinvalid.com').a? }
+-> { DnsCheck.new('boomthisisinvalid.com').a.empty? }
--> { DnsCheck.new('boomthisisinvalid.com').mx? }
+-> { DnsCheck.new('boomthisisinvalid.com').mx.empty? }
--> { DnsCheck.new('boomthisisinvalid.com').ns? }
+-> { DnsCheck.new('boomthisisinvalid.com').ns.empty? }

--> { DnsCheck.new('not even a domain 💩').a? }