Class: MonoVM::Whois::Referral::Follower

Inherits:
Object
  • Object
show all
Defined in:
lib/monovm/whois/referral/follower.rb

Overview

Chases a thin registry's pointer to the registrar's own WHOIS server.

Verisign and the other thin registries hold almost nothing: query .com and the answer is a domain name, a status, nameservers, and a +Registrar WHOIS Server+ line pointing at whoever sold it. The registrant, the contact details and often the accurate expiry date are only on that second server. A client that stops at the first answer reports the thin record as the whole truth.

One deliberate constraint: a referral enriches the record, never the verdict. The registry is authoritative about whether a name exists, and a registrar's server that is down, rate-limiting or simply wrong must not be able to turn a registered domain into an available one.

Constant Summary collapse

SKIP_HOSTS =

Registrars that answer but say nothing useful, or point in a circle. Following these costs a round trip and a rate-limit slot for no data.

[
  "whois.iana.org",
  "whois.markmonitor.com",
  "not.applicable",
  "none"
].freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(transport_factory:, max_hops: 1) ⇒ Follower

Returns a new instance of Follower.

Parameters:

  • transport_factory (Transport::Factory)
  • max_hops (Integer) (defaults to: 1) —

    referral hops to follow; 1 is almost always right



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# File 'lib/monovm/whois/referral/follower.rb', line 35

def initialize(transport_factory:, max_hops: 1)
  @transport_factory = transport_factory
  @max_hops = max_hops
end

Instance Attribute Details

#max_hops ⇒ Object (readonly)

Returns the value of attribute max_hops.



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# File 'lib/monovm/whois/referral/follower.rb', line 31

def max_hops
  @max_hops
end

#transport_factory ⇒ Object (readonly)

Returns the value of attribute transport_factory.



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# File 'lib/monovm/whois/referral/follower.rb', line 31

def transport_factory
  @transport_factory
end

Instance Method Details

#follow(response:, record:, query:) ⇒ Response?

Returns the registrar's answer, or nil when there is no referral to follow or following it failed.

Parameters:

  • response (Response) —

    the registry's answer

  • record (Parser::Record) —

    parsed from that answer

  • query (String) —

    the name being looked up, in wire form

Returns:

  • (Response, nil) —

    the registrar's answer, or nil when there is no referral to follow or following it failed



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# File 'lib/monovm/whois/referral/follower.rb', line 45

def follow(response:, record:, query:)
  return nil unless max_hops.positive?
  return nil unless response.whois?

  host = referral_host(record, response)
  return nil if host.nil?

  fetch(Endpoint.parse("socket://#{host}"), query)
rescue DefinitionsError
  # The referral was not a usable host name; keep the registry's answer.
  nil
end