Accept Follower: Migrate to outbox

includes/class-dispatcher.php

@@ -67,11 +67,7 @@ public static function process_outbox( $id ) {
 		$activity->set_id( $outbox_item->guid );
 		// Pre-fill the Activity with data (for example cc and to).
 		$activity->from_json( $outbox_item->post_content );
-
-		// If the activity doesn't have an actor, set the actor to the post author.
-		if ( ! $activity->get_actor() ) {
-			$activity->set_actor( Actors::get_by_id( $outbox_item->post_author )->get_id() );
-		}
+		$activity->set_actor( Actors::get_by_id( $outbox_item->post_author )->get_id() );
 
 		// Use simple Object (only ID-URI) for Like and Announce.
 		if ( 'Like' === $type ) {

includes/functions.php

@@ -9,6 +9,7 @@
 
 use WP_Error;
 use Activitypub\Activity\Activity;
+use Activitypub\Activity\Base_Object;
 use Activitypub\Collection\Actors;
 use Activitypub\Collection\Outbox;
 use Activitypub\Collection\Followers;
@@ -1600,3 +1601,62 @@ function add_to_outbox( $data, $activity_type = 'Create', $user_id = 0, $content
 
 	return $outbox_activity_id;
 }
+
+/**
+ * Check if an object is an Activity.
+ *
+ * @param array|object $data The object to check.
+ *
+ * @see https://www.w3.org/ns/activitystreams#activities
+ *
+ * @return boolean True if the object is an Activity, false otherwise.
+ */
+function is_activity( $data ) {
+	/**
+	 * Filters the activity types.
+	 *
+	 * @param array $types The activity types.
+	 */
+	$types = apply_filters(
+		'activitypub_activity_types',
+		array(
+			'Accept',
+			'Add',
+			'Announce',
+			'Arrive',
+			'Block',
+			'Create',
+			'Delete',
+			'Dislike',
+			'Follow',
+			'Flag',
+			'Ignore',
+			'Invite',
+			'Join',
+			'Leave',
+			'Like',
+			'Listen',
+			'Move',
+			'Offer',
+			'Read',
+			'Reject',
+			'Remove',
+			'TentativeAccept',
+			'TentativeReject',
+			'Travel',
+			'Undo',
+			'Update',
+			'View',
+		)
+	);
+
+	if ( is_array( $data ) && isset( $data['type'] ) ) {
+		return in_array( $data['type'], $types, true );
+	}
+
+	if ( is_object( $data ) && $data instanceof Base_Object ) {
+		return in_array( $data->get_type(), $types, true );
+	}
+
+	return false;
+}

includes/handler/class-follow.php

@@ -13,6 +13,8 @@
 use Activitypub\Collection\Actors;
 use Activitypub\Collection\Followers;
 
+use function Activitypub\add_to_outbox;
+
 /**
  * Handle Follow requests.
  */
@@ -102,21 +104,9 @@ public static function send_follow_response( $actor, $activity_object, $user_id,
 			)
 		);
 
-		$user = Actors::get_by_id( $user_id );
-
-		// Get inbox.
-		$inbox = $follower->get_shared_inbox();
-
-		// Send "Accept" activity.
-		$activity = new Activity();
-		$activity->set_type( 'Accept' );
-		$activity->set_object( $activity_object );
-		$activity->set_actor( $user->get_id() );
-		$activity->set_to( $actor );
-		$activity->set_id( $user->get_id() . '#follow-' . \preg_replace( '~^https?://~', '', $actor ) . '-' . \time() );
-
-		$activity = $activity->to_json();
+		// Send response only to the Follower.
+		$activity_object['to'] = $actor;
 
-		Http::post( $inbox, $activity, $user_id );
+		add_to_outbox( $activity_object, 'Accept', $user_id, ACTIVITYPUB_CONTENT_VISIBILITY_PRIVATE );
 	}
 }

includes/transformer/class-json.php

@@ -9,6 +9,8 @@
 
 use Activitypub\Activity\Base_Object;
 
+use function Activitypub\is_activity;
+
 /**
  * String Transformer Class file.
  */
@@ -22,10 +24,17 @@ class Json extends Activity_Object {
 	public function __construct( $item ) {
 		$object = new Base_Object();
 
+		// Check if the item is an Activity or an Object.
+		if ( is_activity( $item ) ) {
+			$class = '\Activitypub\Activity\Activity';
+		} else {
+			$class = '\Activitypub\Activity\Base_Object';
+		}
+
 		if ( is_array( $item ) ) {
-			$object = Base_Object::init_from_array( $item );
+			$object = $class::init_from_array( $item );
 		} elseif ( is_string( $item ) ) {
-			$object = Base_Object::init_from_json( $item );
+			$object = $class::init_from_json( $item );
 		}
 
 		parent::__construct( $object );

tests/includes/class-test-functions.php

@@ -216,4 +216,111 @@ public function object_to_uri_provider() {
 			),
 		);
 	}
+
+	/**
+	 * Test is_activity with array input.
+	 *
+	 * @covers ::is_activity
+	 */
+	public function test_is_activity_with_array() {
+		// Test valid activity types.
+		$valid_activities = array(
+			array( 'type' => 'Create' ),
+			array( 'type' => 'Update' ),
+			array( 'type' => 'Delete' ),
+			array( 'type' => 'Follow' ),
+			array( 'type' => 'Accept' ),
+			array( 'type' => 'Reject' ),
+			array( 'type' => 'Add' ),
+			array( 'type' => 'Remove' ),
+			array( 'type' => 'Like' ),
+			array( 'type' => 'Announce' ),
+			array( 'type' => 'Undo' ),
+		);
+
+		foreach ( $valid_activities as $activity ) {
+			$this->assertTrue(
+				\Activitypub\is_activity( $activity ),
+				sprintf( 'Activity type %s should be valid', $activity['type'] )
+			);
+		}
+
+		// Test invalid activity types.
+		$invalid_activities = array(
+			array( 'type' => 'Note' ),
+			array( 'type' => 'Article' ),
+			array( 'type' => 'Person' ),
+			array( 'type' => 'Image' ),
+			array( 'type' => 'Video' ),
+			array( 'type' => 'Audio' ),
+			array( 'type' => '' ),
+			array( 'type' => null ),
+			array(),
+		);
+
+		foreach ( $invalid_activities as $activity ) {
+			$this->assertFalse(
+				\Activitypub\is_activity( $activity ),
+				sprintf( 'Activity type %s should be invalid', isset( $activity['type'] ) ? $activity['type'] : 'null' )
+			);
+		}
+	}
+
+	/**
+	 * Test is_activity with object input.
+	 *
+	 * @covers ::is_activity
+	 */
+	public function test_is_activity_with_object() {
+		// Test Activity object.
+		$activity = new \Activitypub\Activity\Activity();
+		$activity->set_type( 'Create' );
+		$this->assertTrue( \Activitypub\is_activity( $activity ), 'Activity object should be valid' );
+
+		// Test Base_Object.
+		$object = new \Activitypub\Activity\Base_Object();
+		$object->set_type( 'Note' );
+		$this->assertFalse( \Activitypub\is_activity( $object ), 'Base_Object should be invalid' );
+
+		// Test with custom filter.
+		add_filter(
+			'activitypub_activity_types',
+			function ( $types ) {
+				$types[] = 'CustomActivity';
+				return $types;
+			}
+		);
+
+		$activity = new \Activitypub\Activity\Activity();
+		$activity->set_type( 'CustomActivity' );
+		$this->assertTrue(
+			\Activitypub\is_activity( $activity ),
+			'Custom activity type should be valid after filter'
+		);
+
+		remove_all_filters( 'activitypub_activity_types' );
+	}
+
+	/**
+	 * Test is_activity with invalid input.
+	 *
+	 * @covers ::is_activity
+	 */
+	public function test_is_activity_with_invalid_input() {
+		$invalid_inputs = array(
+			'string',
+			123,
+			true,
+			false,
+			null,
+			new \stdClass(),
+		);
+
+		foreach ( $invalid_inputs as $input ) {
+			$this->assertFalse(
+				\Activitypub\is_activity( $input ),
+				sprintf( 'Input of type %s should be invalid', gettype( $input ) )
+			);
+		}
+	}
 }

tests/includes/handler/class-test-follow.php

@@ -0,0 +1,124 @@
+<?php
+/**
+ * Test file for Follow handler.
+ *
+ * @package ActivityPub
+ */
+
+namespace Activitypub\Tests\Handler;
+
+use Activitypub\Handler\Follow;
+use Activitypub\Model\Follower;
+use Activitypub\Collection\Outbox;
+use WP_UnitTestCase;
+
+/**
+ * Test class for Follow handler.
+ *
+ * @coversDefaultClass \Activitypub\Handler\Follow
+ */
+class Test_Follow extends WP_UnitTestCase {
+	/**
+	 * Test user ID.
+	 *
+	 * @var int
+	 */
+	protected static $user_id;
+
+	/**
+	 * Create fake data before tests run.
+	 *
+	 * @param WP_UnitTest_Factory $factory Helper that creates fake data.
+	 */
+	public static function wpSetUpBeforeClass( $factory ) {
+		self::$user_id = $factory->user->create(
+			array(
+				'role' => 'author',
+			)
+		);
+	}
+
+	/**
+	 * Clean up after tests.
+	 */
+	public static function wpTearDownAfterClass() {
+		wp_delete_user( self::$user_id );
+	}
+
+	/**
+	 * Test send_follow_response method.
+	 *
+	 * @covers ::send_follow_response
+	 */
+	public function test_send_follow_response() {
+		$actor           = 'https://example.com/actor';
+		$activity_object = array(
+			'id'     => 'https://example.com/activity/123',
+			'type'   => 'Follow',
+			'actor'  => $actor,
+			'object' => 'https://example.com/user/1',
+		);
+
+		// Test with WP_Error follower - should not create outbox entry.
+		$wp_error = new \WP_Error( 'test_error', 'Test Error' );
+		Follow::send_follow_response( $actor, $activity_object, self::$user_id, $wp_error );
+
+		$outbox_posts = get_posts(
+			array(
+				'post_type'   => Outbox::POST_TYPE,
+				'author'      => self::$user_id,
+				'post_status' => 'pending',
+				// phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_query
+				'meta_query'  => array(
+					array(
+						'key'   => '_activitypub_activity_actor',
+						'value' => 'user',
+					),
+				),
+			)
+		);
+		$this->assertEmpty( $outbox_posts, 'No outbox entry should be created for WP_Error follower' );
+
+		// Test with valid follower.
+		$follower = new Follower();
+		$follower->set_actor( $actor );
+		$follower->set_type( 'Person' );
+		$follower->set_inbox( 'https://example.com/inbox' );
+
+		Follow::send_follow_response( $actor, $activity_object, self::$user_id, $follower );
+
+		$outbox_posts = get_posts(
+			array(
+				'post_type'   => Outbox::POST_TYPE,
+				'author'      => self::$user_id,
+				'post_status' => 'pending',
+				// phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_query
+				'meta_query'  => array(
+					array(
+						'key'   => '_activitypub_activity_actor',
+						'value' => 'user',
+					),
+				),
+			)
+		);
+
+		$this->assertCount( 1, $outbox_posts, 'One outbox entry should be created' );
+
+		$outbox_post   = $outbox_posts[0];
+		$activity_type = \get_post_meta( $outbox_post->ID, '_activitypub_activity_type', true );
+		$activity_json = \json_decode( $outbox_post->post_content, true );
+		$visibility    = \get_post_meta( $outbox_post->ID, 'activitypub_content_visibility', true );
+
+		// Verify outbox entry.
+		$this->assertEquals( 'Accept', $activity_type );
+		$this->assertEquals( ACTIVITYPUB_CONTENT_VISIBILITY_PRIVATE, $visibility );
+
+		$this->assertEquals( 'Follow', $activity_json['type'] );
+		$this->assertEquals( 'https://example.com/user/1', $activity_json['object'] );
+		$this->assertEquals( array( $actor ), $activity_json['to'] );
+		$this->assertEquals( $actor, $activity_json['actor'] );
+
+		// Clean up.
+		wp_delete_post( $outbox_post->ID, true );
+	}
+}