diff options
Diffstat (limited to 'app/services/activitypub/fetch_collection_items_service.rb')
-rw-r--r-- | app/services/activitypub/fetch_collection_items_service.rb | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/app/services/activitypub/fetch_collection_items_service.rb b/app/services/activitypub/fetch_collection_items_service.rb new file mode 100644 index 000000000..ef54321de --- /dev/null +++ b/app/services/activitypub/fetch_collection_items_service.rb @@ -0,0 +1,167 @@ +# frozen_string_literal: true + +class ActivityPub::FetchCollectionItemsService < BaseService + include JsonLdHelper + + COOLDOWN = 30.minutes + + # Fetches objects in a collection from a URI or hash and queues them for processing. + # @param collection [Hash, String] Collection hash or URI + # @param account [Account] Owner of the collection + # @param page_limit [Integer] (10) Maximum number of pages to fetch from the collection. + # @param item_limit [Integer] (100) Maximum number of items to fetch from the collection. + # @option options [Boolean] :every_page (false) Whether to fetch every page in the collection, + # even if its items have been previously fetched. By default, fetching will stop if all the + # items on any page have already been fetched. + # @option options [Boolean] :look_ahead (false) Whether to check the next page for unfetched + # items if the current page's items have been previously fetched. If there are unfetched + # items on the next page, fetching will continue. + # @option options [Boolean] :skip_cooldown (false) Skip the fetch cooldown period on the a + # collection URI (e.g., for account migration). + # @option options [Boolean] :include_boosts (false) Whether to skip boosts. Including these + # will cause a LOT of server traffic. + # @return [void] + # @raise [Mastodon::RaceConditionError] Collection is already being fetched. + # @raise [Mastodon::UnexpectedResponseError] Server returned an error while fetching a page. + def call(collection, account, page_limit: 10, item_limit: 100, **options) + uri = value_or_id(collection) + return if uri.blank? || ActivityPub::TagManager.instance.local_uri?(uri) + + uri = collection['partOf'] if collection.is_a?(Hash) && collection['partOf'].present? + + @account = account + @account = account_from_uri(uri) if @account.blank? + set_fetch_account + + return if !options[:skip_cooldown] && Redis.current.get("fetch_collection_cooldown:#{uri}") + + collection = fetch_collection(collection) + return if collection.blank? + + if @account.blank? + @account = account_from_uri(collection['partOf'].presence || collection['id']) + set_fetch_account + end + + fetch_collection_pages(collection, page_limit, item_limit, **options) + end + + private + + def lock_options(uri) + { redis: Redis.current, key: "fetch_collection:#{uri}" } + end + + def set_fetch_account + @on_behalf_of = @account.present? ? @account.followers.local.random.first : nil + end + + def account_from_uri(uri) + ActivityPub::TagManager.instance.uri_to_resource(uri, Account) + end + + def account_id_from_uri(uri) + return if uri.blank? + + Rails.cache.fetch("account_id_from_uri:#{uri}", expires_in: 10.minutes) do + account_from_uri(uri)&.id + end + end + + def valid_item?(item) + item.is_a?(Hash) && + !invalid_uri?(item['id']) && + (item['attributedTo'].present? || item['actor'].present?) && ( + item['object'].blank? || item['type'] == 'Create' && !invalid_uri?(value_or_id(item['object'])) + ) + end + + def uri_with_account_id(item) + object = item['object'].presence || item + [value_or_id(object), object.is_a?(Hash) ? account_id_from_uri(object['attributedTo']) : account_id_from_uri(item['actor'])] + end + + def invalid_uri?(uri) + unsupported_uri_scheme?(uri) || !uri_allowed?(uri) || ActivityPub::TagManager.instance.local_uri?(uri) + end + + def fetch_collection(collection_or_uri) + return (collection_or_uri['id'].present? ? collection_or_uri : nil) if collection_or_uri.is_a?(Hash) + return if !collection_or_uri.is_a?(String) || invalid_origin?(collection_or_uri) + + fetch_resource_without_id_validation(collection_or_uri, @on_behalf_of, true) + end + + def fetch_collection_pages(collection, page_limit, item_limit, **options) + uri = collection['partOf'].presence || collection['id'] + cooldown_key = "fetch_collection_cooldown:#{uri}" + + return if !options[:skip_cooldown] && Redis.current.get(cooldown_key) + + Redis.current.set(cooldown_key, 1, ex: COOLDOWN) + + RedisLock.acquire(lock_options(uri)) do |lock| + raise Mastodon::RaceConditionError unless lock.acquired? + + page = CollectionPage.find_or_create_by(uri: uri, account: @account) + every_page = options[:every_page] + + if page.next.present? + collection = fetch_collection(page.next) + fetch_collection_items(collection, page, page_limit, item_limit, **options) + every_page = false + end + + uri = collection['first'].presence || collection['id'] + page.update!(next: uri) + collection = fetch_collection(uri) if collection['id'] != uri + fetch_collection_items(collection, page, page_limit, item_limit, **options.merge({ every_page: every_page })) + end + end + + def fetch_collection_items(collection, page, page_limit, item_limit, **options) + page_count = 0 + item_count = 0 + seen_pages = Set[page.next] + have_items = false + + while collection.present? && collection['type'].present? + batch = case collection['type'] + when 'Collection', 'CollectionPage' + collection['items'] + when 'OrderedCollection', 'OrderedCollectionPage' + collection['orderedItems'] + end + + break unless batch.is_a?(Array) + + batch_size = [batch.count, item_limit - item_count].min + batch = batch.take(batch_size).select { |item| valid_item?(item) }.map { |item| uri_with_account_id(item) } + result = CollectionItem.import([:uri, :account_id], batch, validate: false, on_duplicate_key_ignore: true) + + if !options[:every_page] && result.ids.blank? + break if have_items || !options[:look_ahead] + + have_items = true + elsif have_items + have_items = false + end + + item_count += result.ids.count + page_count += 1 + + next_page = collection['next'] + break unless item_count < item_limit && page_count < page_limit && next_page.present? + break if seen_pages.include?(next_page) + + sleep [page_count.to_f / 5, 1].min + + seen_pages << next_page + page.update!(next: next_page) + collection = fetch_collection(next_page) + end + + page.delete + ActivityPub::ProcessCollectionItemsWorker.perform_async + end +end |