Merge pull request #318 from Automattic/schedule

update scheduler for followers

activitypub.php

@@ -30,77 +30,73 @@ function init() {
 	\define( 'ACTIVITYPUB_PLUGIN_BASENAME', plugin_basename( __FILE__ ) );
 	\define( 'ACTIVITYPUB_PLUGIN_FILE', plugin_dir_path( __FILE__ ) . '/' . basename( __FILE__ ) );
 
-	\define( 'ACTIVITYPUB_OBJECT', 'ACTIVITYPUB_OBJECT' );
-
-	require_once \dirname( __FILE__ ) . '/includes/table/class-followers.php';
-	require_once \dirname( __FILE__ ) . '/includes/class-http.php';
-	require_once \dirname( __FILE__ ) . '/includes/class-signature.php';
-	require_once \dirname( __FILE__ ) . '/includes/class-webfinger.php';
-	require_once \dirname( __FILE__ ) . '/includes/peer/class-followers.php';
-	require_once \dirname( __FILE__ ) . '/includes/functions.php';
-
-	require_once \dirname( __FILE__ ) . '/includes/model/class-activity.php';
-	require_once \dirname( __FILE__ ) . '/includes/model/class-post.php';
-	require_once \dirname( __FILE__ ) . '/includes/model/class-follower.php';
-
-	require_once \dirname( __FILE__ ) . '/includes/class-migration.php';
 	Migration::init();
-
-	require_once \dirname( __FILE__ ) . '/includes/class-activity-dispatcher.php';
 	Activity_Dispatcher::init();
-
-	require_once \dirname( __FILE__ ) . '/includes/class-activitypub.php';
 	Activitypub::init();
-
-	require_once \dirname( __FILE__ ) . '/includes/collection/class-followers.php';
 	Collection\Followers::init();
 
 	// Configure the REST API route
-	require_once \dirname( __FILE__ ) . '/includes/rest/class-outbox.php';
 	Rest\Outbox::init();
-
-	require_once \dirname( __FILE__ ) . '/includes/rest/class-inbox.php';
 	Rest\Inbox::init();
-
-	require_once \dirname( __FILE__ ) . '/includes/rest/class-followers.php';
 	Rest\Followers::init();
-
-	require_once \dirname( __FILE__ ) . '/includes/rest/class-following.php';
 	Rest\Following::init();
-
-	require_once \dirname( __FILE__ ) . '/includes/rest/class-webfinger.php';
 	Rest\Webfinger::init();
 
-	// load NodeInfo endpoints only if blog is public
-	if ( true === (bool) \get_option( 'blog_public', 1 ) ) {
-		require_once \dirname( __FILE__ ) . '/includes/rest/class-nodeinfo.php';
-		Rest\NodeInfo::init();
-	}
-
-	require_once \dirname( __FILE__ ) . '/includes/class-admin.php';
 	Admin::init();
-
-	require_once \dirname( __FILE__ ) . '/includes/class-hashtag.php';
 	Hashtag::init();
-
-	require_once \dirname( __FILE__ ) . '/includes/class-shortcodes.php';
 	Shortcodes::init();
-
-	require_once \dirname( __FILE__ ) . '/includes/class-mention.php';
 	Mention::init();
-
-	require_once \dirname( __FILE__ ) . '/includes/class-debug.php';
 	Debug::init();
-
-	require_once \dirname( __FILE__ ) . '/includes/class-health-check.php';
 	Health_Check::init();
-
+	Scheduler::init();
-	if ( \WP_DEBUG ) {
-		require_once \dirname( __FILE__ ) . '/includes/debug.php';
-	}
 }
 \add_action( 'plugins_loaded', '\Activitypub\init' );
 
+/**
+ * Class Autoloader
+ */
+spl_autoload_register(
+	function ( $full_class ) {
+		$base_dir = \dirname( __FILE__ ) . '/includes/';
+		$base     = 'activitypub';
+
+		$class = strtolower( $full_class );
+
+		if ( strncmp( $class, $base, strlen( $base ) ) === 0 ) {
+			$class = str_replace( 'activitypub\\', '', $class );
+
+			if ( false !== strpos( $class, '\\' ) ) {
+				$parts    = explode( '\\', $class );
+				$class    = array_pop( $parts );
+				$sub_dir  = implode( '/', $parts );
+				$base_dir = $base_dir . $sub_dir . '/';
+			}
+
+			$filename = 'class-' . strtr( $class, '_', '-' );
+			$file     = $base_dir . $filename . '.php';
+
+			if ( file_exists( $file ) && is_readable( $file ) ) {
+				require_once $file;
+			} else {
+				// translators: %s is the class name
+				\wp_die( sprintf( esc_html__( 'Required class not found or not readable: %s', 'activitypub' ), esc_html( $full_class ) ) );
+			}
+		}
+	}
+);
+
+require_once \dirname( __FILE__ ) . '/includes/functions.php';
+
+// load NodeInfo endpoints only if blog is public
+if ( \get_option( 'blog_public', 1 ) ) {
+	Rest\NodeInfo::init();
+}
+
+$debug_file = \dirname( __FILE__ ) . '/includes/debug.php';
+if ( \WP_DEBUG && file_exists( $debug_file ) && is_readable( $debug_file ) ) {
+	require_once $debug_file;
+}
+
 /**
  * Add plugin settings link
  */
@@ -113,34 +109,32 @@ function plugin_settings_link( $actions ) {
 
 	return \array_merge( $settings_link, $actions );
 }
-\add_filter( 'plugin_action_links_' . plugin_basename( __FILE__ ), '\Activitypub\plugin_settings_link' );
+\add_filter( 'plugin_action_links_' . plugin_basename( __FILE__ ), __NAMESPACE__ . '\plugin_settings_link' );
 
-/**
+\register_activation_hook(
- * Add rewrite rules
+	__FILE__,
- */
+	array(
-function add_rewrite_rules() {
+		__NAMESPACE__ . '\Activitypub',
-	if ( ! \class_exists( 'Webfinger' ) ) {
+		'activate',
-		\add_rewrite_rule( '^.well-known/webfinger', 'index.php?rest_route=/activitypub/1.0/webfinger', 'top' );
+	)
-	}
+);
 
-	if ( ! \class_exists( 'Nodeinfo' ) || ! (bool) \get_option( 'blog_public', 1 ) ) {
+\register_deactivation_hook(
-		\add_rewrite_rule( '^.well-known/nodeinfo', 'index.php?rest_route=/activitypub/1.0/nodeinfo/discovery', 'top' );
+	__FILE__,
-		\add_rewrite_rule( '^.well-known/x-nodeinfo2', 'index.php?rest_route=/activitypub/1.0/nodeinfo2', 'top' );
+	array(
-	}
+		__NAMESPACE__ . '\Activitypub',
+		'deactivate',
+	)
+);
 
-	\add_rewrite_endpoint( 'activitypub', EP_AUTHORS | EP_PERMALINK | EP_PAGES );
+register_uninstall_hook(
-}
+	__FILE__,
-\add_action( 'init', '\Activitypub\add_rewrite_rules', 1 );
+	array(
+		__NAMESPACE__ . '\Activitypub',
+		'uninstall',
+	)
+);
 
-/**
- * Flush rewrite rules;
- */
-function flush_rewrite_rules() {
-	\Activitypub\add_rewrite_rules();
-	\flush_rewrite_rules();
-}
-\register_activation_hook( __FILE__, '\Activitypub\flush_rewrite_rules' );
-\register_deactivation_hook( __FILE__, '\flush_rewrite_rules' );
 
 /**
  * Only load code that needs BuddyPress to run once BP is loaded and initialized.

includes/class-activitypub.php

@@ -22,9 +22,40 @@ class Activitypub {
 			\add_post_type_support( $post_type, 'activitypub' );
 		}
 
-		\add_action( 'transition_post_status', array( self::class, 'schedule_post_activity' ), 33, 3 );
 		\add_action( 'wp_trash_post', array( self::class, 'trash_post' ), 1 );
 		\add_action( 'untrash_post', array( self::class, 'untrash_post' ), 1 );
+
+		\add_action( 'init', array( self::class, 'add_rewrite_rules' ) );
+	}
+
+	/**
+	 * Activation Hook
+	 *
+	 * @return void
+	 */
+	public static function activate() {
+		self::flush_rewrite_rules();
+
+		Scheduler::register_schedules();
+	}
+
+	/**
+	 * Deactivation Hook
+	 *
+	 * @return void
+	 */
+	public static function deactivate() {
+		self::flush_rewrite_rules();
+
+		Scheduler::deregister_schedules();
+	}
+
+	/**
+	 * Uninstall Hook
+	 *
+	 * @return void
+	 */
+	public static function uninstall() {
 	}
 
 	/**
@@ -98,36 +129,6 @@ class Activitypub {
 		return $vars;
 	}
 
-	/**
-	 * Schedule Activities.
-	 *
-	 * @param string  $new_status New post status.
-	 * @param string  $old_status Old post status.
-	 * @param WP_Post $post       Post object.
-	 */
-	public static function schedule_post_activity( $new_status, $old_status, $post ) {
-		// Do not send activities if post is password protected.
-		if ( \post_password_required( $post ) ) {
-			return;
-		}
-
-		// Check if post-type supports ActivityPub.
-		$post_types = \get_post_types_by_support( 'activitypub' );
-		if ( ! \in_array( $post->post_type, $post_types, true ) ) {
-			return;
-		}
-
-		$activitypub_post = new \Activitypub\Model\Post( $post );
-
-		if ( 'publish' === $new_status && 'publish' !== $old_status ) {
-			\wp_schedule_single_event( \time(), 'activitypub_send_create_activity', array( $activitypub_post ) );
-		} elseif ( 'publish' === $new_status ) {
-			\wp_schedule_single_event( \time(), 'activitypub_send_update_activity', array( $activitypub_post ) );
-		} elseif ( 'trash' === $new_status ) {
-			\wp_schedule_single_event( \time(), 'activitypub_send_delete_activity', array( $activitypub_post ) );
-		}
-	}
-
 	/**
 	 * Replaces the default avatar.
 	 *
@@ -146,7 +147,14 @@ class Activitypub {
 		}
 
 		$allowed_comment_types = \apply_filters( 'get_avatar_comment_types', array( 'comment' ) );
-		if ( ! empty( $id_or_email->comment_type ) && ! \in_array( $id_or_email->comment_type, (array) $allowed_comment_types, true ) ) {
+		if (
+			! empty( $id_or_email->comment_type ) &&
+			! \in_array(
+				$id_or_email->comment_type,
+				(array) $allowed_comment_types,
+				true
+			)
+		) {
 			$args['url'] = false;
 			/** This filter is documented in wp-includes/link-template.php */
 			return \apply_filters( 'get_avatar_data', $args, $id_or_email );
@@ -191,7 +199,12 @@ class Activitypub {
 	 * @return void
 	 */
 	public static function trash_post( $post_id ) {
-		\add_post_meta( $post_id, 'activitypub_canonical_url', \get_permalink( $post_id ), true );
+		\add_post_meta(
+			$post_id,
+			'activitypub_canonical_url',
+			\get_permalink( $post_id ),
+			true
+		);
 	}
 
 	/**
@@ -204,4 +217,40 @@ class Activitypub {
 	public static function untrash_post( $post_id ) {
 		\delete_post_meta( $post_id, 'activitypub_canonical_url' );
 	}
+
+	/**
+	 * Add rewrite rules
+	 */
+	public static function add_rewrite_rules() {
+		if ( ! \class_exists( 'Webfinger' ) ) {
+			\add_rewrite_rule(
+				'^.well-known/webfinger',
+				'index.php?rest_route=/activitypub/1.0/webfinger',
+				'top'
+			);
+		}
+
+		if ( ! \class_exists( 'Nodeinfo' ) && true === (bool) \get_option( 'blog_public', 1 ) ) {
+			\add_rewrite_rule(
+				'^.well-known/nodeinfo',
+				'index.php?rest_route=/activitypub/1.0/nodeinfo/discovery',
+				'top'
+			);
+			\add_rewrite_rule(
+				'^.well-known/x-nodeinfo2',
+				'index.php?rest_route=/activitypub/1.0/nodeinfo2',
+				'top'
+			);
+		}
+
+		\add_rewrite_endpoint( 'activitypub', EP_AUTHORS | EP_PERMALINK | EP_PAGES );
+	}
+
+	/**
+	 * Flush rewrite rules;
+	 */
+	public static function flush_rewrite_rules() {
+		self::add_rewrite_rules();
+		\flush_rewrite_rules();
+	}
 }

includes/class-migration.php

@@ -1,9 +1,18 @@
 <?php
 namespace Activitypub;
 
-use Acctivitypub\Model\Follower;
+use Activitypub\Model\Follower;
+use Activitypub\Collection\Followers;
 
+/**
+ * ActivityPub Migration Class
+ *
+ * @author Matthias Pfefferle
+ */
 class Migration {
+	/**
+	 * Initialize the class, registering WordPress hooks
+	 */
 	public static function init() {
 		\add_action( 'activitypub_schedule_migration', array( self::class, 'maybe_migrate' ) );
 	}
@@ -74,7 +83,7 @@ class Migration {
 
 					$follower->upsert();
 
-					$result = wp_set_object_terms( $user_id, $follower->get_actor(), self::TAXONOMY, true );
+					$result = wp_set_object_terms( $user_id, $follower->get_actor(), Followers::TAXONOMY, true );
 				}
 			}
 		}

includes/class-scheduler.php

@@ -0,0 +1,138 @@
+<?php
+
+namespace Activitypub;
+
+use Activitypub\Model\Post;
+use Activitypub\Collection\Followers;
+
+/**
+ * ActivityPub Scheduler Class
+ *
+ * @author Matthias Pfefferle
+ */
+class Scheduler {
+	/**
+	 * Initialize the class, registering WordPress hooks
+	 */
+	public static function init() {
+		\add_action( 'transition_post_status', array( self::class, 'schedule_post_activity' ), 33, 3 );
+
+		\add_action( 'activitypub_update_followers', array( self::class, 'update_followers' ) );
+		\add_action( 'activitypub_cleanup_followers', array( self::class, 'cleanup_followers' ) );
+	}
+
+	/**
+	 * Schedule all ActivityPub schedules.
+	 *
+	 * @return void
+	 */
+	public static function register_schedules() {
+		if ( ! \wp_next_scheduled( 'activitypub_update_followers' ) ) {
+			\wp_schedule_event( time(), 'hourly', 'activitypub_update_followers' );
+		}
+
+		if ( ! \wp_next_scheduled( 'activitypub_cleanup_followers' ) ) {
+			\wp_schedule_event( time(), 'daily', 'activitypub_cleanup_followers' );
+		}
+	}
+
+	/**
+	 * Unscedule all ActivityPub schedules.
+	 *
+	 * @return void
+	 */
+	public static function deregister_schedules() {
+		wp_unschedule_hook( 'activitypub_update_followers' );
+		wp_unschedule_hook( 'activitypub_cleanup_followers' );
+	}
+
+
+	/**
+	 * Schedule Activities.
+	 *
+	 * @param string  $new_status New post status.
+	 * @param string  $old_status Old post status.
+	 * @param WP_Post $post       Post object.
+	 */
+	public static function schedule_post_activity( $new_status, $old_status, $post ) {
+		// Do not send activities if post is password protected.
+		if ( \post_password_required( $post ) ) {
+			return;
+		}
+
+		// Check if post-type supports ActivityPub.
+		$post_types = \get_post_types_by_support( 'activitypub' );
+		if ( ! \in_array( $post->post_type, $post_types, true ) ) {
+			return;
+		}
+
+		$activitypub_post = new Post( $post );
+
+		if ( 'publish' === $new_status && 'publish' !== $old_status ) {
+			\wp_schedule_single_event(
+				\time(),
+				'activitypub_send_create_activity',
+				array( $activitypub_post )
+			);
+		} elseif ( 'publish' === $new_status ) {
+			\wp_schedule_single_event(
+				\time(),
+				'activitypub_send_update_activity',
+				array( $activitypub_post )
+			);
+		} elseif ( 'trash' === $new_status ) {
+			\wp_schedule_single_event(
+				\time(),
+				'activitypub_send_delete_activity',
+				array( $activitypub_post )
+			);
+		}
+	}
+
+	/**
+	 * Update followers
+	 *
+	 * @return void
+	 */
+	public static function update_followers() {
+		$followers = Followers::get_outdated_followers();
+
+		foreach ( $followers as $follower ) {
+			$meta = get_remote_metadata_by_actor( $follower->get_actor() );
+
+			if ( empty( $meta ) || ! is_array( $meta ) || is_wp_error( $meta ) ) {
+				$follower->set_error( $meta );
+			} else {
+				$follower->from_meta( $meta );
+			}
+
+			$follower->update();
+		}
+	}
+
+	/**
+	 * Cleanup followers
+	 *
+	 * @return void
+	 */
+	public static function cleanup_followers() {
+		$followers = Followers::get_faulty_followers();
+
+		foreach ( $followers as $follower ) {
+			$meta = get_remote_metadata_by_actor( $follower->get_actor() );
+
+			if ( is_tombstone( $meta ) ) {
+				$follower->delete();
+			} elseif ( empty( $meta ) || ! is_array( $meta ) || is_wp_error( $meta ) ) {
+				if ( 5 <= $follower->count_errors() ) {
+					$follower->delete();
+				} else {
+					$follower->set_error( $meta );
+					$follower->update();
+				}
+			} else {
+				$follower->reset_errors();
+			}
+		}
+	}
+}

includes/class-shortcodes.php

@@ -3,14 +3,12 @@ namespace Activitypub;
 
 class Shortcodes {
 	/**
-	 * Class constructor, registering WordPress then shortcodes
+	 * Initialize the class, registering WordPress hooks
-	 *
-	 * @param WP_Post  $post    A WordPress Post Object
 	 */
 	public static function init() {
-		foreach ( get_class_methods( 'Activitypub\Shortcodes' ) as $shortcode ) {
+		foreach ( get_class_methods( self::class ) as $shortcode ) {
 			if ( 'init' !== $shortcode ) {
-				add_shortcode( 'ap_' . $shortcode, array( 'Activitypub\Shortcodes', $shortcode ) );
+				add_shortcode( 'ap_' . $shortcode, array( self::class, $shortcode ) );
 			}
 		}
 	}

includes/collection/class-followers.php

@@ -143,7 +143,7 @@ class Followers {
 				'single'            => true,
 				'sanitize_callback' => function( $value ) {
 					if ( ! is_numeric( $value ) && (int) $value !== $value ) {
-						$value = strtotime( 'now' );
+						$value = \time();
 					}
 
 					return $value;
@@ -186,7 +186,7 @@ class Followers {
 	}
 
 	/**
-	 * Handles "Unfollow" requests
+	 * Handle "Unfollow" requests
 	 *
 	 * @param array $object  The JSON "Undo" Activity
 	 * @param int   $user_id The ID of the ID of the WordPress User
@@ -202,7 +202,7 @@ class Followers {
 	}
 
 	/**
-	 * Add a new Follower
+	 * Add new Follower
 	 *
 	 * @param int    $user_id The ID of the WordPress User
 	 * @param string $actor   The Actor URL
@@ -316,7 +316,7 @@ class Followers {
 	 *
 	 * @return array The Term list of Followers, the format depends on $output
 	 */
-	public static function get_followers( $user_id, $output = ARRAY_N, $number = null, $offset = null, $args = array() ) {
+	public static function get_followers( $user_id, $number = null, $offset = null, $args = array() ) {
 		$defaults = array(
 			'taxonomy'   => self::TAXONOMY,
 			'hide_empty' => false,
@@ -329,25 +329,13 @@ class Followers {
 
 		$args  = wp_parse_args( $args, $defaults );
 		$terms = new WP_Term_Query( $args );
-
 		$items = array();
 
-		// change output format
-		switch ( $output ) {
-			case ACTIVITYPUB_OBJECT:
 		foreach ( $terms->get_terms() as $follower ) {
 			$items[] = new Follower( $follower->name ); // phpcs:ignore
 		}
+
 		return $items;
-			case OBJECT:
-				return $terms->get_terms();
-			case ARRAY_N:
-			default:
-				foreach ( $terms->get_terms() as $follower ) {
-					$items[] = $follower->name; // phpcs:ignore
-				}
-				return $items;
-		}
 	}
 
 	/**
@@ -404,4 +392,70 @@ class Followers {
 
 		return array_filter( $results );
 	}
+
+	/**
+	 * Get all Followers that have not been updated for a given time
+	 *
+	 * @param enum $output     The output format, supported ARRAY_N, OBJECT and ACTIVITYPUB_OBJECT.
+	 * @param int  $number     Limits the result.
+	 * @param int  $older_than The time in seconds.
+	 *
+	 * @return mixed The Term list of Followers, the format depends on $output.
+	 */
+	public static function get_outdated_followers( $number = 50, $older_than = 604800 ) {
+		$args = array(
+			'taxonomy'   => self::TAXONOMY,
+			'number'     => $number,
+			'meta_key'   => 'updated_at',
+			'orderby'    => 'meta_value_num',
+			'order'      => 'DESC',
+			'meta_query' => array(
+				array(
+					'key'        => 'updated_at',
+					'value'      => time() - $older_than,
+					'type'       => 'numeric',
+					'compare'    => '<=',
+				),
+			),
+		);
+
+		$terms = new WP_Term_Query( $args );
+		$items = array();
+
+		foreach ( $terms->get_terms() as $follower ) {
+			$items[] = new Follower( $follower->name ); // phpcs:ignore
+		}
+
+		return $items;
+	}
+
+	/**
+	 * Get all Followers that had errors
+	 *
+	 * @param enum    $output The output format, supported ARRAY_N, OBJECT and ACTIVITYPUB_OBJECT
+	 * @param integer $number The number of Followers to return.
+	 *
+	 * @return mixed The Term list of Followers, the format depends on $output.
+	 */
+	public static function get_faulty_followers( $number = 10 ) {
+		$args = array(
+			'taxonomy'   => self::TAXONOMY,
+			'number'     => $number,
+			'meta_query' => array(
+				array(
+					'key'        => 'errors',
+					'compare'    => 'EXISTS',
+				),
+			),
+		);
+
+		$terms = new WP_Term_Query( $args );
+		$items = array();
+
+		foreach ( $terms->get_terms() as $follower ) {
+			$items[] = new Follower( $follower->name ); // phpcs:ignore
+		}
+
+		return $items;
+	}
 }

includes/model/class-activity.php

@@ -97,7 +97,7 @@ class Activity {
 		}
 
 		$this->type = \ucfirst( $type );
-		$this->published = \gmdate( 'Y-m-d\TH:i:s\Z', \strtotime( 'now' ) );
+		$this->published = \gmdate( 'Y-m-d\TH:i:s\Z', \time() );
 	}
 
 	/**

includes/model/class-follower.php

@@ -139,8 +139,8 @@ class Follower {
 	/**
 	 * Magic function to implement getter and setter
 	 *
-	 * @param string $method
+	 * @param string $method The method name.
-	 * @param string $params
+	 * @param string $params The method params.
 	 *
 	 * @return void
 	 */
@@ -159,6 +159,22 @@ class Follower {
 		}
 	}
 
+	/**
+	 * Magic function to return the Actor-URL when the Object is used as a string
+	 *
+	 * @return string
+	 */
+	public function __toString() {
+		return $this->get_actor();
+	}
+
+	/**
+	 * Prefill the Object with the meta data.
+	 *
+	 * @param array $meta The meta data.
+	 *
+	 * @return void
+	 */
 	public function from_meta( $meta ) {
 		$this->meta = $meta;
 
@@ -178,9 +194,16 @@ class Follower {
 			$this->shared_inbox = $meta['inbox'];
 		}
 
-		$this->updated_at = \strtotime( 'now' );
+		$this->updated_at = \time();
 	}
 
+	/**
+	 * Get the data by the given attribute
+	 *
+	 * @param string $attribute The attribute name.
+	 *
+	 * @return mixed The attribute value.
+	 */
 	public function get( $attribute ) {
 		if ( $this->$attribute ) {
 			return $this->$attribute;
@@ -201,6 +224,23 @@ class Follower {
 		return null;
 	}
 
+	/**
+	 * Set new Error
+	 *
+	 * @param mixed $error The latest HTTP-Error.
+	 *
+	 * @return void
+	 */
+	public function set_error( $error ) {
+		$this->errors = array();
+		$this->error  = $error;
+	}
+
+	/**
+	 * Get the errors.
+	 *
+	 * @return mixed
+	 */
 	public function get_errors() {
 		if ( $this->errors ) {
 			return $this->errors;
@@ -210,6 +250,20 @@ class Follower {
 		return $this->errors;
 	}
 
+	/**
+	 * Reset (delete) all errors.
+	 *
+	 * @return void
+	 */
+	public function reset_errors() {
+		delete_term_meta( $this->id, 'errors' );
+	}
+
+	/**
+	 * Count the errors.
+	 *
+	 * @return int The number of errors.
+	 */
 	public function count_errors() {
 		$errors = $this->get_errors();
 
@@ -220,6 +274,11 @@ class Follower {
 		return 0;
 	}
 
+	/**
+	 * Return the latest error message.
+	 *
+	 * @return string The error message.
+	 */
 	public function get_latest_error_message() {
 		$errors = $this->get_errors();
 
@@ -230,6 +289,13 @@ class Follower {
 		return '';
 	}
 
+	/**
+	 * Get the meta data by the given attribute.
+	 *
+	 * @param string $attribute The attribute name.
+	 *
+	 * @return mixed $attribute The attribute value.
+	 */
 	public function get_meta_by( $attribute ) {
 		$meta = $this->get_meta();
 
@@ -248,6 +314,11 @@ class Follower {
 		return null;
 	}
 
+	/**
+	 * Get the meta data.
+	 *
+	 * @return array $meta The meta data.
+	 */
 	public function get_meta() {
 		if ( $this->meta ) {
 			return $this->meta;
@@ -256,6 +327,11 @@ class Follower {
 		return null;
 	}
 
+	/**
+	 * Update the current Follower-Object.
+	 *
+	 * @return void
+	 */
 	public function update() {
 		$term = wp_update_term(
 			$this->id,
@@ -265,10 +341,15 @@ class Follower {
 			)
 		);
 
-		$this->updated_at = \strtotime( 'now' );
+		$this->updated_at = \time();
 		$this->update_term_meta();
 	}
 
+	/**
+	 * Save the current Follower-Object.
+	 *
+	 * @return void
+	 */
 	public function save() {
 		$term = wp_insert_term(
 			$this->actor,
@@ -284,6 +365,11 @@ class Follower {
 		$this->update_term_meta();
 	}
 
+	/**
+	 * Upsert the current Follower-Object.
+	 *
+	 * @return void
+	 */
 	public function upsert() {
 		if ( $this->id ) {
 			$this->update();
@@ -292,6 +378,20 @@ class Follower {
 		}
 	}
 
+	/**
+	 * Delete the current Follower-Object.
+	 *
+	 * @return void
+	 */
+	public function delete() {
+		wp_delete_term( $this->id, Followers::TAXONOMY );
+	}
+
+	/**
+	 * Update the term meta.
+	 *
+	 * @return void
+	 */
 	protected function update_term_meta() {
 		$attributes = array( 'inbox', 'shared_inbox', 'avatar', 'updated_at', 'name', 'username' );
 
@@ -312,6 +412,5 @@ class Follower {
 
 			add_term_meta( $this->id, 'errors', $error );
 		}
-
 	}
 }

includes/rest/class-followers.php

@@ -81,7 +81,13 @@ class Followers {
 		$json->partOf = \get_rest_url( null, "/activitypub/1.0/users/$user_id/followers" ); // phpcs:ignore
 		$json->first = $json->partOf; // phpcs:ignore
 		$json->totalItems = FollowerCollection::count_followers( $user_id ); // phpcs:ignore
-		$json->orderedItems = FollowerCollection::get_followers( $user_id, ARRAY_N ); // phpcs:ignore
+		// phpcs:ignore
+		$json->orderedItems = array_map(
+			function( $item ) {
+				return $item->get_actor();
+			},
+			FollowerCollection::get_followers( $user_id )
+		);
 
 		$response = new WP_REST_Response( $json, 200 );
 		$response->header( 'Content-Type', 'application/activity+json' );

includes/table/class-followers.php

@@ -35,7 +35,7 @@ class Followers extends WP_List_Table {
 		$page_num = $this->get_pagenum();
 		$per_page = 20;
 
-		$follower = FollowerCollection::get_followers( \get_current_user_id(), ACTIVITYPUB_OBJECT, $per_page, ( $page_num - 1 ) * $per_page );
+		$follower = FollowerCollection::get_followers( \get_current_user_id(), $per_page, ( $page_num - 1 ) * $per_page );
 		$counter  = FollowerCollection::count_followers( \get_current_user_id() );
 
 		$this->items = array();

tests/test-class-db-activitypub-followers.php

@@ -58,6 +58,13 @@ class Test_Db_Activitypub_Followers extends WP_UnitTestCase {
 
 		$this->assertEquals( 3, \count( $db_followers ) );
 
+		$db_followers = array_map(
+			function( $item ) {
+				return $item->get_actor();
+			},
+			$db_followers
+		);
+
 		$this->assertSame( array( 'https://example.com/author/jon', 'https://example.org/author/doe', 'http://sally.example.org' ), $db_followers );
 	}
 
@@ -90,6 +97,60 @@ class Test_Db_Activitypub_Followers extends WP_UnitTestCase {
 		$this->assertNull( $follower );
 	}
 
+	public function test_get_outdated_followers() {
+		$followers = array( 'https://example.com/author/jon', 'https://example.org/author/doe', 'http://sally.example.org' );
+
+		$pre_http_request = new MockAction();
+		add_filter( 'pre_http_request', array( $pre_http_request, 'filter' ), 10, 3 );
+
+		foreach ( $followers as $follower ) {
+			\Activitypub\Collection\Followers::add_follower( 1, $follower );
+		}
+
+		$follower = new \Activitypub\Model\Follower( 'https://example.com/author/jon' );
+
+		update_term_meta( $follower->get_id(), 'updated_at', \time() - 804800 );
+
+		$followers = \Activitypub\Collection\Followers::get_outdated_followers();
+		$this->assertEquals( 1, count( $followers ) );
+		$this->assertEquals( 'https://example.com/author/jon', $followers[0] );
+	}
+
+	public function test_get_faulty_followers() {
+		$followers = array( 'https://example.com/author/jon', 'https://example.org/author/doe', 'http://sally.example.org' );
+
+		$pre_http_request = new MockAction();
+		add_filter( 'pre_http_request', array( $pre_http_request, 'filter' ), 10, 3 );
+
+		foreach ( $followers as $follower ) {
+			\Activitypub\Collection\Followers::add_follower( 1, $follower );
+		}
+
+		$follower = new \Activitypub\Model\Follower( 'http://sally.example.org' );
+
+		for ( $i = 1; $i <= 15; $i++ ) {
+			add_term_meta( $follower->get_id(), 'errors', 'error ' . $i );
+		}
+
+		$follower = new \Activitypub\Model\Follower( 'http://sally.example.org' );
+		$count = $follower->count_errors();
+
+		$followers = \Activitypub\Collection\Followers::get_faulty_followers();
+
+		$this->assertEquals( 1, count( $followers ) );
+		$this->assertEquals( 'http://sally.example.org', $followers[0] );
+
+		$follower->reset_errors();
+
+		$follower = new \Activitypub\Model\Follower( 'http://sally.example.org' );
+		$count = $follower->count_errors();
+
+		$followers = \Activitypub\Collection\Followers::get_faulty_followers();
+
+		$this->assertEquals( 0, count( $followers ) );
+	}
+
+
 	public static function http_request_host_is_external( $in, $host ) {
 		if ( in_array( $host, array( 'example.com', 'example.org' ), true ) ) {
 			return true;