Add "Move Account" functionality

activitypub.php

@@ -72,6 +72,7 @@ function rest_init() {
  */
 function plugin_init() {
 	\add_action( 'init', array( __NAMESPACE__ . '\Migration', 'init' ) );
+	\add_action( 'init', array( __NAMESPACE__ . '\Move', 'init' ) );
 	\add_action( 'init', array( __NAMESPACE__ . '\Activitypub', 'init' ) );
 	\add_action( 'init', array( __NAMESPACE__ . '\Activity_Dispatcher', 'init' ) );
 	\add_action( 'init', array( __NAMESPACE__ . '\Handler', 'init' ) );

includes/activity/class-actor.php

@@ -42,6 +42,14 @@ class Actor extends Base_Object {
 				'@id' => 'lemmy:moderators',
 				'@type' => '@id',
 			),
+			'alsoKnownAs' => array(
+				'@id' => 'as:alsoKnownAs',
+				'@type' => '@id',
+			),
+			'movedTo' => array(
+				'@id' => 'as:movedTo',
+				'@type' => '@id',
+			),
 			'postingRestrictedToMods' => 'lemmy:postingRestrictedToMods',
 			'discoverable' => 'toot:discoverable',
 			'indexable' => 'toot:indexable',

includes/class-move.php

@@ -0,0 +1,96 @@
+<?php
+namespace Activitypub;
+
+/**
+ * ActivityPub (Account) Move Class
+ *
+ * @author Matthias Pfefferle
+ */
+class Move {
+	/**
+	 * Initialize the class, registering WordPress hooks
+	 */
+	public static function init() {
+		\add_filter( 'activitypub_activity_user_object_array', array( self::class, 'extend_actor_profiles' ), 10, 3 );
+	}
+
+	/**
+	 * Extend the actor profiles and add the "movedTo" and "alsoKnownAs" properties
+	 *
+	 * @param array $actor the actor profile
+	 *
+	 * @return array the extended actor profile
+	 */
+	public static function extend_actor_profiles( $actor, $id, $user ) {
+		// Check if the user is a valid user object
+		if ( ! $user instanceof \Activitypub\Model\User ) {
+			return $actor;
+		}
+
+		$move_to_host = apply_filters( 'activitypub_move_actor_to_host', false, $id, $user );
+
+		if ( $move_to_host && is_string( $move_to_host ) ) {
+			$actor['movedTo'] = self::normalize_host( $move_to_host, $user->get_id() );
+		}
+
+		$move_from_host = apply_filters( 'activitypub_move_actor_from_host', false, $id, $user );
+
+		if ( $move_from_host && is_array( $move_from_host ) ) {
+			$actor['alsoKnownAs'] = self::normalize_hosts( $move_from_host, $user->get_id() );
+		}
+
+		return $actor;
+	}
+
+	/**
+	 * Add settings to the admin interface
+	 *
+	 * @return void
+	 */
+	public static function add_settings() {
+
+	}
+
+	/**
+	 * Normalize the host
+	 *
+	 * Returns the host if it is a valid URL, otherwise it tries to replace
+	 * the host of the Actor-ID with the new host
+	 *
+	 * @param string $host_or_url the host or the url
+	 * @param string $id          the Actor-ID (URL)
+	 *
+	 * @return string the normalized host
+	 */
+	public static function normalize_host( $host_or_url, $id ) {
+		// if it is a valid URL use it
+		if ( filter_var( $host_or_url, FILTER_VALIDATE_URL ) ) {
+			return $host_or_url;
+		}
+
+		// otherwise try to replace the host of the Actor-ID with the new host
+		$id = str_replace( wp_parse_url( get_home_url(), PHP_URL_HOST ), $host_or_url, $id );
+
+		return $id;
+	}
+
+	/**
+	 * Normalize the hosts
+	 *
+	 * Returns an array of normalized hosts
+	 *
+	 * @param string $hosts_or_urls the host or the url
+	 * @param string $id            the Actor-ID (URL)
+	 *
+	 * @return array the normalized hosts
+	 */
+	public static function normalize_hosts( $hosts_or_urls, $id ) {
+		$normalized_hosts = array();
+
+		foreach ( $hosts_or_urls as $host_or_url ) {
+			$normalized_hosts[] = self::normalize_host( $host_or_url, $id );
+		}
+
+		return $normalized_hosts;
+	}
+}