- # frozen_string_literal: true
-
- class ActivityPub::FetchRemoteActorService < BaseService
- include JsonLdHelper
- include DomainControlHelper
- include WebfingerHelper
-
- class Error < StandardError; end
-
- SUPPORTED_TYPES = %w(Application Group Organization Person Service).freeze
-
- # Does a WebFinger roundtrip on each call, unless `only_key` is true
- def call(uri, id: true, prefetched_body: nil, break_on_redirect: false, only_key: false, suppress_errors: true, request_id: nil)
- return if domain_not_allowed?(uri)
- return ActivityPub::TagManager.instance.uri_to_actor(uri) if ActivityPub::TagManager.instance.local_uri?(uri)
-
- @json = begin
- if prefetched_body.nil?
- fetch_resource(uri, id)
- else
- body_to_json(prefetched_body, compare_id: id ? uri : nil)
- end
- rescue Oj::ParseError
- raise Error, "Error parsing JSON-LD document #{uri}"
- end
-
- raise Error, "Error fetching actor JSON at #{uri}" if @json.nil?
- raise Error, "Unsupported JSON-LD context for document #{uri}" unless supported_context?
- raise Error, "Unexpected object type for actor #{uri} (expected any of: #{SUPPORTED_TYPES})" unless expected_type?
- raise Error, "Actor #{uri} has moved to #{@json['movedTo']}" if break_on_redirect && @json['movedTo'].present?
- raise Error, "Actor #{uri} has no 'preferredUsername', which is a requirement for Mastodon compatibility" unless @json['preferredUsername'].present?
-
- @uri = @json['id']
- @username = @json['preferredUsername']
- @domain = Addressable::URI.parse(@uri).normalized_host
-
- check_webfinger! unless only_key
-
- ActivityPub::ProcessAccountService.new.call(@username, @domain, @json, only_key: only_key, verified_webfinger: !only_key, request_id: request_id)
- rescue Error => e
- Rails.logger.debug { "Fetching actor #{uri} failed: #{e.message}" }
- raise unless suppress_errors
- end
-
- private
-
- def check_webfinger!
- webfinger = webfinger!("acct:#{@username}@#{@domain}")
- confirmed_username, confirmed_domain = split_acct(webfinger.subject)
-
- if @username.casecmp(confirmed_username).zero? && @domain.casecmp(confirmed_domain).zero?
- raise Error, "Webfinger response for #{@username}@#{@domain} does not loop back to #{@uri}" if webfinger.link('self', 'href') != @uri
-
- return
- end
-
- webfinger = webfinger!("acct:#{confirmed_username}@#{confirmed_domain}")
- @username, @domain = split_acct(webfinger.subject)
-
- raise Webfinger::RedirectError, "Too many webfinger redirects for URI #{@uri} (stopped at #{@username}@#{@domain})" unless confirmed_username.casecmp(@username).zero? && confirmed_domain.casecmp(@domain).zero?
-
- raise Error, "Webfinger response for #{@username}@#{@domain} does not loop back to #{@uri}" if webfinger.link('self', 'href') != @uri
- rescue Webfinger::RedirectError => e
- raise Error, e.message
- rescue Webfinger::Error => e
- raise Error, "Webfinger error when resolving #{@username}@#{@domain}: #{e.message}"
- end
-
- def split_acct(acct)
- acct.gsub(/\Aacct:/, '').split('@')
- end
-
- def supported_context?
- super(@json)
- end
-
- def expected_type?
- equals_or_includes_any?(@json['type'], SUPPORTED_TYPES)
- end
- end
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