AsyncDNS-cr  Check-in [baf27b579c]

require "./query"
require "./resolver"

# AsyncDNS is an asynchronous DNS resolver.
# It is a port of ObjFW's <https://objfw.nil.im> OFDNSResolver & friends.
module AsyncDNS
  VERSION = "0.1.0"
end

require "./dns_class"
require "./rr_type"

module AsyncDNS
  class Query
    getter :domain_name, :dns_class, :rr_type
    getter :name, :class, :type

    def initialize(@domain_name : String, @dns_class : DNSClass,
                   @rr_type : RRType)
    def initialize(@name : String, @class : DNSClass, @type : RRType)
    end
  end
end

require "./rr"
require "./settings"
require "./response"

module AsyncDNS
  class Resolver
    getter :settings
    setter :settings

    enum Error
      NO_NAME_SERVER
    end

    private struct Context
      def initialize(@id : UInt16, @settings : Settings,
                     @block : Response | Error ->)
      end
    end

    def initialize
      @settings = Settings.new
      @queries = Hash(UInt16, Context).new
      @tcp_queries = Hash(Socket, Context).new
    end

    def resolve(query, &block : Response | Error ->)
      id : UInt16
      while true
        id = Random::Secure.rand(UInt16::MIN..UInt16::MAX)
        break unless @queries.has_key?(id)
      end

      if @settings.nameservers.empty?
        yield Error::NO_NAME_SERVER
        return
      end

      send(Context.new(id, settings.dup, block))
    end

    def send(context : Context)
      @queries[context.@id] = context

      # TODO
    end

    def stop
      # TODO
    end
  end
end

module AsyncDNS
  class Settings
    @local_domain : String?

    property static_hosts, nameservers, local_domain, search_domains, uses_tcp
    getter timeout, max_attempts, abs_num_dots
    property :static_hosts, :nameservers, :local_domain, :search_domains,
      :uses_tcp, :reload_period
    getter :timeout, :max_attempts, :abs_num_dots

    def timeout=(timeout)
      if timeout < Time::Span.zero
      raise ArgumentError.new("timeout must be positive") if timeout < 0
        raise ArgumentError.new("timeout must be positive")
      end

      @timeout = timeout
    end

    def max_attempts=(max_attempts)
      if max_attempts < 0
        raise ArgumentError.new("max_attempts must be positive")

require "../src/asyncdns"

AsyncDNS::RR::A.new("crystal-lang.org", Socket::IPAddress.new("127.0.0.1", 0),
  1234)

AsyncDNS::Query.new("crystal-lang.org", AsyncDNS::DNSClass::IN,
query = AsyncDNS::Query.new("crystal-lang.org", AsyncDNS::DNSClass::IN,
  AsyncDNS::RRType::A)

resolver = AsyncDNS::Resolver.new

resolver.resolve(query) { |response| p response }
AsyncDNS::RR::A.new("crystal-lang.org", Socket::IPAddress.new("127.0.0.1", 0),
  1234)