Fix outbox not using object types other than Base_Object

CHANGELOG.md

@@ -22,6 +22,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * Negotiation of ActivityPub requests for custom post types when queried by the ActivityPub ID.
 * Avoid PHP warnings when using Debug mode and when the `actor` is not set.
 * No longer creates Outbox items when importing content/users.
+* Outbox is now capable of sending other object types that are not Base_Object.
 
 ## [5.0.0] - 2025-02-03
 

includes/activity/class-activity.php

@@ -151,14 +151,16 @@ class Activity extends Base_Object {
 	 * @see https://www.w3.org/TR/activitypub/#object-without-create
 	 *
 	 * @param array|string|Base_Object|Link|null $data Activity object.
+	 * @param string|null                        $object_class The full class path to a child of Base_Object.
 	 *
 	 * @return void
 	 */
-	public function set_object( $data ) {
+	public function set_object( $data, $object_class = null ) {
 		// Convert array to object.
 		if ( is_array( $data ) ) {
-			// Check if the item is an Activity or an Object.
-			if ( is_activity( $data ) ) {
+			if ( $object_class && class_exists( $object_class ) ) {
+				$data = $object_class::init_from_array( $data );
+			} elseif ( is_activity( $data ) ) { // Check if the item is an Activity or an Object.
 				$data = self::init_from_array( $data );
 			} elseif ( is_actor( $data ) ) {
 				$data = Actor::init_from_array( $data );

includes/class-activitypub.php

@@ -594,6 +594,28 @@ private static function register_post_types() {
 			)
 		);
 
+		/**
+		 * Register ActivityPub object class for Outbox items.
+		 *
+		 * @see https://www.w3.org/TR/activitystreams-vocabulary/#object-types
+		 */
+		\register_post_meta(
+			Outbox::POST_TYPE,
+			'_activitypub_object_class',
+			array(
+				'type'              => 'string',
+				'description'       => 'The full class name of the object class',
+				'single'            => true,
+				'sanitize_callback' => function ( $value ) {
+					if ( class_exists( $value ) ) {
+						return $value;
+					}
+
+					return \Activitypub\Activity\Base_Object::class;
+				},
+			)
+		);
+
 		\register_post_meta(
 			Outbox::POST_TYPE,
 			'_activitypub_activity_actor',

includes/class-dispatcher.php

@@ -60,12 +60,13 @@ public static function process_outbox( $id ) {
 				break;
 		}
 
-		$type     = \get_post_meta( $outbox_item->ID, '_activitypub_activity_type', true );
-		$activity = new Activity();
+		$type         = \get_post_meta( $outbox_item->ID, '_activitypub_activity_type', true );
+		$object_class = \get_post_meta( $outbox_item->ID, '_activitypub_object_class', true );
+		$activity     = new Activity();
 		$activity->set_type( $type );
 		$activity->set_id( $outbox_item->guid );
 		// Pre-fill the Activity with data (for example cc and to).
-		$activity->set_object( \json_decode( $outbox_item->post_content, true ) );
+		$activity->set_object( \json_decode( $outbox_item->post_content, true ), $object_class );
 		$activity->set_actor( Actors::get_by_id( $outbox_item->post_author )->get_id() );
 
 		// Use simple Object (only ID-URI) for Like and Announce.

includes/collection/class-outbox.php

@@ -7,6 +7,8 @@
 
 namespace Activitypub\Collection;
 
+use Activitypub\Activity\Base_Object;
+
 /**
  * ActivityPub Outbox Collection
  *
@@ -52,6 +54,12 @@ public static function add( $activity_object, $activity_type, $user_id, $content
 			),
 		);
 
+		$object_class = get_class( $activity_object );
+
+		if (  Base_Object::class !== $object_class ) {
+			$outbox_item['meta_input']['_activitypub_object_class'] = str_replace( '\\', '\\\\', $object_class );
+		}
+
 		$has_kses = false !== \has_filter( 'content_save_pre', 'wp_filter_post_kses' );
 		if ( $has_kses ) {
 			// Prevent KSES from corrupting JSON in post_content.

readme.txt

@@ -140,6 +140,7 @@ For reasons of data protection, it is not possible to see the followers of other
 * Fixed: Negotiation of ActivityPub requests for custom post types when queried by the ActivityPub ID.
 * Fixed: Avoid PHP warnings when using Debug mode and when the `actor` is not set.
 * Fixed: No longer creates Outbox items when importing content/users.
+* Fixed: Outbox is now capable of sending other object types that are not Base_Object.
 
 = 5.0.0 =