Gab Social. All are welcome.

app/lib/activitypub/activity.rb

@@ -0,0 +1,187 @@
+# frozen_string_literal: true
+
+class ActivityPub::Activity
+  include JsonLdHelper
+  include Redisable
+
+  SUPPORTED_TYPES = %w(Note Question).freeze
+  CONVERTED_TYPES = %w(Image Video Article Page).freeze
+
+  def initialize(json, account, **options)
+    @json    = json
+    @account = account
+    @object  = @json['object']
+    @options = options
+  end
+
+  def perform
+    raise NotImplementedError
+  end
+
+  class << self
+    def factory(json, account, **options)
+      @json = json
+      klass&.new(json, account, options)
+    end
+
+    private
+
+    def klass
+      case @json['type']
+      when 'Create'
+        ActivityPub::Activity::Create
+      when 'Announce'
+        ActivityPub::Activity::Announce
+      when 'Delete'
+        ActivityPub::Activity::Delete
+      when 'Follow'
+        ActivityPub::Activity::Follow
+      when 'Like'
+        ActivityPub::Activity::Like
+      when 'Block'
+        ActivityPub::Activity::Block
+      when 'Update'
+        ActivityPub::Activity::Update
+      when 'Undo'
+        ActivityPub::Activity::Undo
+      when 'Accept'
+        ActivityPub::Activity::Accept
+      when 'Reject'
+        ActivityPub::Activity::Reject
+      when 'Flag'
+        ActivityPub::Activity::Flag
+      when 'Add'
+        ActivityPub::Activity::Add
+      when 'Remove'
+        ActivityPub::Activity::Remove
+      when 'Move'
+        ActivityPub::Activity::Move
+      end
+    end
+  end
+
+  protected
+
+  def status_from_uri(uri)
+    ActivityPub::TagManager.instance.uri_to_resource(uri, Status)
+  end
+
+  def account_from_uri(uri)
+    ActivityPub::TagManager.instance.uri_to_resource(uri, Account)
+  end
+
+  def object_uri
+    @object_uri ||= value_or_id(@object)
+  end
+
+  def unsupported_object_type?
+    @object.is_a?(String) || !(supported_object_type? || converted_object_type?)
+  end
+
+  def supported_object_type?
+    equals_or_includes_any?(@object['type'], SUPPORTED_TYPES)
+  end
+
+  def converted_object_type?
+    equals_or_includes_any?(@object['type'], CONVERTED_TYPES)
+  end
+
+  def distribute(status)
+    crawl_links(status)
+
+    notify_about_reblog(status) if reblog_of_local_account?(status)
+    notify_about_mentions(status)
+
+    # Only continue if the status is supposed to have arrived in real-time.
+    # Note that if @options[:override_timestamps] isn't set, the status
+    # may have a lower snowflake id than other existing statuses, potentially
+    # "hiding" it from paginated API calls
+    return unless @options[:override_timestamps] || status.within_realtime_window?
+
+    distribute_to_followers(status)
+  end
+
+  def reblog_of_local_account?(status)
+    status.reblog? && status.reblog.account.local?
+  end
+
+  def notify_about_reblog(status)
+    NotifyService.new.call(status.reblog.account, status)
+  end
+
+  def notify_about_mentions(status)
+    status.active_mentions.includes(:account).each do |mention|
+      next unless mention.account.local? && audience_includes?(mention.account)
+      NotifyService.new.call(mention.account, mention)
+    end
+  end
+
+  def crawl_links(status)
+    return if status.spoiler_text?
+
+    # Spread out crawling randomly to avoid DDoSing the link
+    LinkCrawlWorker.perform_in(rand(1..59).seconds, status.id)
+  end
+
+  def distribute_to_followers(status)
+    ::DistributionWorker.perform_async(status.id)
+  end
+
+  def delete_arrived_first?(uri)
+    redis.exists("delete_upon_arrival:#{@account.id}:#{uri}")
+  end
+
+  def delete_later!(uri)
+    redis.setex("delete_upon_arrival:#{@account.id}:#{uri}", 6.hours.seconds, uri)
+  end
+
+  def status_from_object
+    # If the status is already known, return it
+    status = status_from_uri(object_uri)
+
+    return status unless status.nil?
+
+    # If the reposted gab is embedded and it is a self-repost, handle it like a Create
+    unless unsupported_object_type?
+      actor_id = value_or_id(first_of_value(@object['attributedTo'])) || @account.uri
+
+      if actor_id == @account.uri
+        return ActivityPub::Activity.factory({ 'type' => 'Create', 'actor' => actor_id, 'object' => @object }, @account).perform
+      end
+    end
+
+    fetch_remote_original_status
+  end
+
+  def fetch_remote_original_status
+    if object_uri.start_with?('http')
+      return if ActivityPub::TagManager.instance.local_uri?(object_uri)
+      ActivityPub::FetchRemoteStatusService.new.call(object_uri, id: true, on_behalf_of: @account.followers.local.first)
+    elsif @object['url'].present?
+      ::FetchRemoteStatusService.new.call(@object['url'])
+    end
+  end
+
+  def lock_or_return(key, expire_after = 7.days.seconds)
+    yield if redis.set(key, true, nx: true, ex: expire_after)
+  ensure
+    redis.del(key)
+  end
+
+  def fetch?
+    !@options[:delivery]
+  end
+
+  def followed_by_local_accounts?
+    @account.passive_relationships.exists?
+  end
+
+  def requested_through_relay?
+    @options[:relayed_through_account] && Relay.find_by(inbox_url: @options[:relayed_through_account].inbox_url)&.enabled?
+  end
+
+  def reject_payload!
+    Rails.logger.info("Rejected #{@json['type']} activity #{@json['id']} from #{@account.uri}#{@options[:relayed_through_account] && "via #{@options[:relayed_through_account].uri}"}")
+    nil
+  end
+end