Add in_reply_to Actor to Activity audience

.github/changelog/1711-from-description

@@ -0,0 +1,4 @@
+Significance: minor
+Type: added
+
+The actor of the replied-to post is now included in cc or to based on the post's visibility.

includes/class-http.php

@@ -235,6 +235,17 @@ public static function generate_cache_key( $url ) {
 	 * @return array|WP_Error The Object data as array or WP_Error on failure.
 	 */
 	public static function get_remote_object( $url_or_object, $cached = true ) {
+		/**
+		 * Filters the preemptive return value of a remote object request.
+		 *
+		 * @param array|string|null $response      The response.
+		 * @param array|string|null $url_or_object The Object or the Object URL.
+		 */
+		$response = apply_filters( 'activitypub_pre_http_get_remote_object', null, $url_or_object );
+		if ( null !== $response ) {
+			return $response;
+		}
+
 		$url = object_to_uri( $url_or_object );
 
 		if ( preg_match( '/^@?' . ACTIVITYPUB_USERNAME_REGEXP . '$/i', $url ) ) {

includes/transformer/class-base.php

@@ -7,10 +7,13 @@
 
 namespace Activitypub\Transformer;
 
+use Activitypub\Http;
 use Activitypub\Activity\Activity;
 use Activitypub\Collection\Actors;
 use Activitypub\Activity\Base_Object;
 
+use function Activitypub\object_to_uri;
+
 /**
  * WordPress Base Transformer.
  *
@@ -117,7 +120,7 @@ protected function transform_object_properties( $activity_object ) {
 	/**
 	 * Transform the item into an ActivityPub Object.
 	 *
-	 * @return Base_Object|object The Activity-Object.
+	 * @return Base_Object The Activity-Object.
 	 */
 	public function to_object() {
 		$activity_object = new Base_Object();
@@ -162,28 +165,40 @@ public function set_content_visibility( $content_visibility ) {
 	 * @return Base_Object The ActivityPub Object.
 	 */
 	protected function set_audience( $activity_object ) {
-		$public = 'https://www.w3.org/ns/activitystreams#Public';
-		$actor  = Actors::get_by_resource( $this->get_attributed_to() );
-		if ( ! $actor || is_wp_error( $actor ) ) {
-			$followers = null;
-		} else {
+		$public     = 'https://www.w3.org/ns/activitystreams#Public';
+		$followers  = null;
+		$replied_to = null;
+
+		$actor = Actors::get_by_resource( $this->get_attributed_to() );
+		if ( ! \is_wp_error( $actor ) ) {
 			$followers = $actor->get_followers();
 		}
+
 		$mentions = array_values( $this->get_mentions() );
 
+		if ( $this->get_in_reply_to() ) {
+			$object = Http::get_remote_object( $this->get_in_reply_to() );
+			if ( $object && ! \is_wp_error( $object ) && isset( $object['attributedTo'] ) ) {
+				$replied_to = array( object_to_uri( $object['attributedTo'] ) );
+			}
+		}
+
 		switch ( $this->get_content_visibility() ) {
 			case ACTIVITYPUB_CONTENT_VISIBILITY_PUBLIC:
 				$activity_object->add_to( $public );
 				$activity_object->add_cc( $followers );
 				$activity_object->add_cc( $mentions );
+				$activity_object->add_cc( $replied_to );
 				break;
 			case ACTIVITYPUB_CONTENT_VISIBILITY_QUIET_PUBLIC:
 				$activity_object->add_to( $followers );
 				$activity_object->add_to( $mentions );
+				$activity_object->add_to( $replied_to );
 				$activity_object->add_cc( $public );
 				break;
 			case ACTIVITYPUB_CONTENT_VISIBILITY_PRIVATE:
 				$activity_object->add_to( $mentions );
+				$activity_object->add_to( $replied_to );
 		}
 
 		return $activity_object;
@@ -379,4 +394,13 @@ protected function get_mentions() {
 			$this->item
 		);
 	}
+
+	/**
+	 * Returns the in reply to.
+	 *
+	 * @return string|array|null The in reply to.
+	 */
+	protected function get_in_reply_to() {
+		return null;
+	}
 }

includes/transformer/class-post.php

@@ -606,7 +606,7 @@ public function generate_reply_link( $block_content, $block ) {
 	 *
 	 * @see https://www.w3.org/TR/activitystreams-vocabulary/#dfn-inreplyto
 	 *
-	 * @return string|null The in-reply-to URL of the post.
+	 * @return string|array|null The in-reply-to URL of the post.
 	 */
 	protected function get_in_reply_to() {
 		if ( ! site_supports_blocks() ) {

tests/includes/transformer/class-test-base.php

@@ -7,9 +7,11 @@
 
 namespace Activitypub\Tests\Transformer;
 
+use Activitypub\Http;
 use Activitypub\Activity\Base_Object;
+use Activitypub\Activity\Generic_Object;
 use Activitypub\Transformer\Base;
-
+use Activitypub\Transformer\Post;
 /**
  * Test class for Base Transformer.
  *
@@ -70,4 +72,146 @@ public function get_object_var_keys() {
 		// Assert that the sensitive property could be set to false.
 		$this->assertFalse( $transformed_object->get_sensitive(), 'The sensitive property should be set to false.' );
 	}
+
+	/**
+	 * Test that the audience is set correctly.
+	 *
+	 * @dataProvider data_provider_set_audience
+	 *
+	 * @covers ::set_audience
+	 *
+	 * @param string $content_visibility The content visibility.
+	 * @param array  $object_attributes  The object attributes.
+	 * @param array  $expected_audience  The expected audience.
+	 */
+	public function test_set_audience( $content_visibility, $object_attributes, $expected_audience ) {
+		$post_id = $this->factory->post->create(
+			array(
+				'post_title'   => 'Test Post',
+				'post_content' => 'Test content that is longer than the note length limit',
+			)
+		);
+		$post    = \get_post( $post_id );
+
+		$function = function ( $response, $url_or_object ) {
+			if ( ! str_contains( $url_or_object, 'reply' ) ) {
+				return null;
+			}
+
+			return array(
+				'attributedTo' => $url_or_object,
+			);
+		};
+		\add_filter( 'activitypub_pre_http_get_remote_object', $function, 10, 2 );
+
+		$getter_methods = array_map(
+			function ( $k ) {
+				return 'get_' . $k;
+			},
+			array_keys( $object_attributes )
+		);
+
+		$transformer = $this->getMockBuilder( Post::class )
+			->setConstructorArgs( array( $post ) )
+			->onlyMethods( $getter_methods )
+			->getMock();
+
+		$transformer->set_content_visibility( $content_visibility );
+
+		foreach ( $object_attributes as $key => $value ) {
+			$transformer->method( 'get_' . $key )->willReturn( $value );
+		}
+
+		$reflection = new \ReflectionObject( $transformer );
+		$method     = $reflection->getMethod( 'set_audience' );
+		$method->setAccessible( true );
+
+		$transformed_object = $method->invoke( $transformer, new Generic_Object() );
+
+		$this->assertEquals( $expected_audience['to'], $transformed_object->get_to() );
+		$this->assertEquals( $expected_audience['cc'], $transformed_object->get_cc() );
+
+		\wp_delete_post( $post_id );
+		\remove_filter( 'activitypub_pre_http_get_remote_object', $function );
+	}
+
+	/**
+	 * Data provider for test_set_audience.
+	 *
+	 * @return array[]
+	 */
+	public function data_provider_set_audience() {
+		return array(
+			array(
+				ACTIVITYPUB_CONTENT_VISIBILITY_PUBLIC,
+				array(
+					'in_reply_to' => 'https://example.com/in-reply-to',
+					'mentions'    => array(
+						'https://example.com/mentions' => 'https://example.com/mentions',
+					),
+				),
+				array(
+					'to' => array(
+						'https://www.w3.org/ns/activitystreams#Public',
+					),
+					'cc' => array(
+						'https://example.com/mentions',
+						'https://example.com/in-reply-to',
+					),
+				),
+			),
+			array(
+				ACTIVITYPUB_CONTENT_VISIBILITY_PUBLIC,
+				array(
+					'in_reply_to' => 'https://example.com/in-reply-to',
+					'mentions'    => array(
+						'https://example.com/mentions' => 'https://example.com/mentions',
+					),
+				),
+				array(
+					'to' => array(
+						'https://www.w3.org/ns/activitystreams#Public',
+					),
+					'cc' => array(
+						'https://example.com/mentions',
+						'https://example.com/in-reply-to',
+					),
+				),
+			),
+			array(
+				ACTIVITYPUB_CONTENT_VISIBILITY_QUIET_PUBLIC,
+				array(
+					'in_reply_to' => 'https://example.com/in-reply-to',
+					'mentions'    => array(
+						'https://example.com/mentions' => 'https://example.com/mentions',
+					),
+				),
+				array(
+					'cc' => array(
+						'https://www.w3.org/ns/activitystreams#Public',
+					),
+					'to' => array(
+						'https://example.com/mentions',
+						'https://example.com/in-reply-to',
+					),
+				),
+			),
+			array(
+				ACTIVITYPUB_CONTENT_VISIBILITY_PRIVATE,
+				array(
+					'in_reply_to' => 'https://example.com/in-reply-to',
+					'mentions'    => array(
+						'https://example.com/mentions' => 'https://example.com/mentions',
+					),
+				),
+				array(
+					'to' => array(
+						'https://example.com/mentions',
+						'https://example.com/in-reply-to',
+					),
+					'cc' => null,
+				),
+			),
+		);
+	}
 }