mastodon/app/services/activitypub/fetch_remote_status_service.rb
2025-05-02 22:16:04 -07:00

103 lines
3.8 KiB
Ruby

# frozen_string_literal: true
class ActivityPub::FetchRemoteStatusService < BaseService
include JsonLdHelper
include DomainControlHelper
include Redisable
DISCOVERIES_PER_REQUEST = 1000
# Should be called when uri has already been checked for locality
def call(uri, prefetched_body: nil, on_behalf_of: nil, expected_actor_uri: nil, request_id: nil)
return if domain_not_allowed?(uri)
# load the account if given as an ID
on_behalf_of = Account.find(on_behalf_of) unless on_behalf_of.nil? || on_behalf_of.is_a?(Account)
@request_id = request_id || "#{Time.now.utc.to_i}-status-#{uri}"
@json = if prefetched_body.nil?
fetch_status(uri, true, on_behalf_of)
else
body_to_json(prefetched_body, compare_id: uri)
end
return unless supported_context?
actor_uri = nil
activity_json = nil
object_uri = nil
if expected_object_type?
actor_uri = value_or_id(first_of_value(@json['attributedTo']))
activity_json = { 'type' => 'Create', 'actor' => actor_uri, 'object' => @json }
object_uri = uri_from_bearcap(@json['id'])
elsif expected_activity_type?
actor_uri = value_or_id(first_of_value(@json['actor']))
activity_json = @json
object_uri = uri_from_bearcap(value_or_id(@json['object']))
end
return if activity_json.nil? || object_uri.nil? || !trustworthy_attribution?(@json['id'], actor_uri)
return if expected_actor_uri.present? && actor_uri != expected_actor_uri
return ActivityPub::TagManager.instance.uri_to_resource(object_uri, Status) if ActivityPub::TagManager.instance.local_uri?(object_uri)
actor = account_from_uri(actor_uri)
return if actor.nil? || actor.suspended?
# If we fetched a status that already exists, then we need to treat the
# activity as an update rather than create
activity_json['type'] = 'Update' if equals_or_includes_any?(activity_json['type'], %w(Create)) && Status.exists?(uri: object_uri, account_id: actor.id)
with_redis do |redis|
discoveries = redis.incr("status_discovery_per_request:#{@request_id}")
redis.expire("status_discovery_per_request:#{@request_id}", 5.minutes.seconds)
return nil if discoveries > DISCOVERIES_PER_REQUEST
end
ActivityPub::Activity.factory(activity_json, actor, request_id: @request_id).perform
end
private
def trustworthy_attribution?(uri, attributed_to)
return false if uri.nil? || attributed_to.nil?
Addressable::URI.parse(uri).normalized_host.casecmp(Addressable::URI.parse(attributed_to).normalized_host).zero?
end
def account_from_uri(uri)
actor = ActivityPub::TagManager.instance.uri_to_resource(uri, Account)
actor = ActivityPub::FetchRemoteAccountService.new.call(uri, request_id: @request_id) if actor.nil? || actor.possibly_stale?
actor
end
def supported_context?
super(@json)
end
def expected_activity_type?
equals_or_includes_any?(@json['type'], %w(Create Announce))
end
def expected_object_type?
equals_or_includes_any?(@json['type'], ActivityPub::Activity::Create::SUPPORTED_TYPES + ActivityPub::Activity::Create::CONVERTED_TYPES)
end
def fetch_status(uri, id_is_known, on_behalf_of = nil)
begin
fetch_resource(uri, id_is_known, on_behalf_of, raise_on_error: :all)
rescue Mastodon::UnexpectedResponseError => e
return unless e.response.code == 404
# If this is a 404 from a public status from a remote account, delete it
existing_status = Status.remote.find_by(uri: uri)
if existing_status&.distributable?
Rails.logger.debug { "FetchRemoteStatusService - Got 404 for orphaned status with URI #{uri}, deleting" }
Tombstone.find_or_create_by(uri: uri, account: existing_status.account)
RemoveStatusService.new.call(existing_status, redraft: false)
end
end
end
end