mastofe

fetch_remote_account_service.rb (1848B)

# frozen_string_literal: true
class ActivityPub::FetchRemoteAccountService < BaseService
  include JsonLdHelper
  SUPPORTED_TYPES = %w(Application Group Organization Person Service).freeze
  # Should be called when uri has already been checked for locality
  # Does a WebFinger roundtrip on each call
  def call(uri, id: true, prefetched_body: nil)
    @json = if prefetched_body.nil?
              fetch_resource(uri, id)
            else
              body_to_json(prefetched_body)
            end
    return unless supported_context? && expected_type?
    @uri      = @json['id']
    @username = @json['preferredUsername']
    @domain   = Addressable::URI.parse(@uri).normalized_host
    return unless verified_webfinger?
    ActivityPub::ProcessAccountService.new.call(@username, @domain, @json)
  rescue Oj::ParseError
    nil
  end
  private
  def verified_webfinger?
    webfinger                            = Goldfinger.finger("acct:#{@username}@#{@domain}")
    confirmed_username, confirmed_domain = split_acct(webfinger.subject)
    return webfinger.link('self')&.href == @uri if @username.casecmp(confirmed_username).zero? && @domain.casecmp(confirmed_domain).zero?
    webfinger                            = Goldfinger.finger("acct:#{confirmed_username}@#{confirmed_domain}")
    @username, @domain                   = split_acct(webfinger.subject)
    self_reference                       = webfinger.link('self')
    return false unless @username.casecmp(confirmed_username).zero? && @domain.casecmp(confirmed_domain).zero?
    return false if self_reference&.href != @uri
    true
  rescue Goldfinger::Error
    false
  end
  def split_acct(acct)
    acct.gsub(/\Aacct:/, '').split('@')
  end
  def supported_context?
    super(@json)
  end
  def expected_type?
    SUPPORTED_TYPES.include?(@json['type'])
  end
end