Class: Nondisposable::DisposableDomain

Inherits:
ApplicationRecord
  • Object
show all
Defined in:
app/models/nondisposable/disposable_domain.rb

Constant Summary collapse

PARENT_MATCH_DEPTH =

How many leading labels the parent-domain walk strips when check_parent_domains is enabled: user@a.b.c.tempmail.com is checked as a.b.c.tempmail.com, b.c.tempmail.com, c.tempmail.com and tempmail.com.

Trade-off (documented instead of pulling in a full public-suffix-list dependency): the walk never queries single-label suffixes (bare TLDs like "com"), but without a PSL it cannot tell that multi-label suffixes like "co.uk" are public — those candidates are harmless unless a public suffix is deliberately added to the list. Conversely, a throwaway address nested more than 3 labels below a listed domain escapes the walk; blocklisted domains are registrable domains, so 3 levels covers practical abuse.

3

Class Method Summary collapse

Class Method Details

.disposable?(domain) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'app/models/nondisposable/disposable_domain.rb', line 21

def disposable?(domain)
  return false if domain.blank?

  domain = domain.to_s.downcase
  config = Nondisposable.configuration
  candidates = match_candidates(domain)

  additional = config.additional_domains.map { |d| d.to_s.downcase }
  return true if (candidates & additional).any? # rubocop compat: Array#intersect? needs Ruby >= 3.1, gem supports 3.0

  excluded = config.excluded_domains.map { |d| d.to_s.downcase }
  # An exact exclusion always wins, so a specific subdomain can be
  # allowlisted even when a parent domain is on the list.
  return false if excluded.include?(domain)

  where(name: candidates - excluded).exists?
end

.match_candidates(domain) ⇒ Object

The exact domain plus up to PARENT_MATCH_DEPTH parent domains, never descending below two labels (bare TLDs are never candidates).



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# File 'app/models/nondisposable/disposable_domain.rb', line 41

def match_candidates(domain)
  return [domain] unless Nondisposable.configuration.check_parent_domains

  labels = domain.split('.')
  candidates = [domain]
  1.upto(PARENT_MATCH_DEPTH) do |depth|
    parent = labels.drop(depth)
    break if parent.size < 2

    candidates << parent.join('.')
  end
  candidates
end