mastodon/app/services/activitypub/fetch_replies_service.rb
2025-05-02 22:40:42 -07:00

36 lines
1.2 KiB
Ruby

# frozen_string_literal: true
class ActivityPub::FetchRepliesService < BaseService
include JsonLdHelper
# Limit of fetched replies
MAX_REPLIES = 5
def call(reference_uri, collection_or_uri, max_pages: 1, allow_synchronous_requests: true, request_id: nil)
@reference_uri = reference_uri
return if !allow_synchronous_requests && !collection_or_uri.is_a?(Hash)
# if given a prefetched collection while forbidding synchronous requests,
# process it and return without fetching additional pages
max_pages = 1 if !allow_synchronous_requests && collection_or_uri.is_a?(Hash)
@items, n_pages = collection_items(collection_or_uri, max_pages: max_pages, max_items: MAX_REPLIES, reference_uri: @reference_uri)
return if @items.nil?
@items = filter_replies(@items)
FetchReplyWorker.push_bulk(@items) { |reply_uri| [reply_uri, { 'request_id' => request_id }] }
[@items, n_pages]
end
private
def filter_replies(items)
# Only fetch replies to the same server as the original status to avoid
# amplification attacks.
# Also limit to 5 fetched replies to limit potential for DoS.
items.map { |item| value_or_id(item) }.reject { |uri| non_matching_uri_hosts?(@reference_uri, uri) }.take(MAX_REPLIES)
end
end