mastodon/app/controllers/activitypub/inboxes_controller.rb

# frozen_string_literal: true

class ActivityPub::InboxesController < ActivityPub::BaseController
  include JsonLdHelper

  before_action :skip_large_payload
  before_action :decorate_trace
  before_action :skip_unknown_actor_activity
  before_action :require_actor_signature!
  skip_before_action :authenticate_user!

  def create
    upgrade_account
    process_collection_synchronization
    process_payload
    head 202
  end

  private

  def skip_large_payload
    head 413 if request.content_length > ActivityPub::Activity::MAX_JSON_SIZE
  end

  def decorate_trace
    ActivityPub::OpenTelemetry.decorate_current_span(payload: parsed_body)
  end

  def skip_unknown_actor_activity
    head 202 if unknown_affected_account?
  end

  def unknown_affected_account?
    json = parsed_body
    return false if json.nil?

    json.is_a?(Hash) && %w(Delete Update).include?(json['type']) && json['actor'].present? && json['actor'] == value_or_id(json['object']) && !Account.exists?(uri: json['actor'])
  end

  def account_required?
    params[:account_username].present?
  end

  def skip_temporary_suspension_response?
    true
  end

  def skip_pending_deletion_response?
    true
  end

  def body
    return @body if defined?(@body)

    @body = request.body.read
    @body.presence&.force_encoding('UTF-8')

    request.body.rewind if request.body.respond_to?(:rewind)

    @body
  end

  def parsed_body
    return @parsed_body if defined?(@parsed_body)

    @parsed_body = JSON.parse(body)
  rescue JSON::ParserError
    @parsed_body = nil
  end

  def upgrade_account
    if signed_request_account&.ostatus?
      signed_request_account.update(last_webfingered_at: nil)
      ResolveAccountWorker.perform_async(signed_request_account.acct)
    end

    DeliveryFailureTracker.reset!(signed_request_actor.inbox_url)
  end

  def process_collection_synchronization
    raw_params = request.headers['Collection-Synchronization']
    return if raw_params.blank? || ENV['DISABLE_FOLLOWERS_SYNCHRONIZATION'] == 'true' || signed_request_account.nil?

    # Re-using the syntax for signature parameters
    params = SignatureParser.parse(raw_params)

    ActivityPub::PrepareFollowersSynchronizationService.new.call(signed_request_account, params)
  rescue SignatureParser::ParsingError
    Rails.logger.warn 'Error parsing Collection-Synchronization header'
  end

  def process_payload
    ActivityPub::ProcessingWorker.perform_async(signed_request_actor.id, body, @account&.id, signed_request_actor.class.name)
  end
end