Implement a proper Tombstone handling

.github/changelog/2066-from-description

@@ -0,0 +1,4 @@
+Significance: minor
+Type: added
+
+Improved handling of deleted content with a new unified system for better tracking and compatibility.

includes/class-activitypub.php

@@ -117,6 +117,11 @@ public static function render_activitypub_template( $template ) {
 			return $template;
 		}
 
+		if ( Tombstone::check_local_url( Query::get_instance()->get_request_url() ) ) {
+			\status_header( 410 );
+			return ACTIVITYPUB_PLUGIN_DIR . 'templates/tombstone-json.php';
+		}
+
 		$activitypub_template = false;
 		$activitypub_object   = Query::get_instance()->get_activitypub_object();
 

includes/class-http.php

@@ -182,27 +182,9 @@ public static function get( $url, $cached = false ) {
 	 * @return bool True if the URL is a tombstone.
 	 */
 	public static function is_tombstone( $url ) {
-		/**
-		 * Fires before checking if the URL is a tombstone.
-		 *
-		 * @param string $url The URL to check.
-		 */
-		\do_action( 'activitypub_pre_http_is_tombstone', $url );
-
-		$response = \wp_safe_remote_get( $url, array( 'headers' => array( 'Accept' => 'application/activity+json' ) ) );
-		$code     = \wp_remote_retrieve_response_code( $response );
-
-		if ( in_array( (int) $code, array( 404, 410 ), true ) ) {
-			return true;
-		}
-
-		$data = \wp_remote_retrieve_body( $response );
-		$data = \json_decode( $data, true );
-		if ( $data && isset( $data['type'] ) && 'Tombstone' === $data['type'] ) {
-			return true;
-		}
+		_deprecated_function( __METHOD__, 'unreleased', 'Activitypub\Tombstone::check_remote_url' );
 
-		return false;
+		return Tombstone::check_remote_url( $url );
 	}
 
 	/**

includes/class-query.php

@@ -248,7 +248,7 @@ protected function maybe_get_virtual_object() {
 	 *
 	 * @return string|null The request URL.
 	 */
-	protected function get_request_url() {
+	public function get_request_url() {
 		if ( ! isset( $_SERVER['REQUEST_URI'] ) ) {
 			return null;
 		}

includes/class-scheduler.php

@@ -194,7 +194,7 @@ public static function cleanup_remote_actors() {
 		foreach ( $actors as $actor ) {
 			$meta = get_remote_metadata_by_actor( $actor->guid, false );
 
-			if ( is_tombstone( $meta ) ) {
+			if ( Tombstone::check( $meta ) ) {
 				\wp_delete_post( $actor->ID );
 			} elseif ( empty( $meta ) || ! is_array( $meta ) || \is_wp_error( $meta ) ) {
 				if ( Actors::count_errors( $actor->ID ) >= 5 ) {

includes/class-tombstone.php

@@ -0,0 +1,167 @@
+<?php
+/**
+ * Tombstone class file.
+ *
+ * @package Activitypub
+ */
+
+namespace Activitypub;
+
+use Activitypub\Activity\Base_Object;
+
+/**
+ * ActivityPub Tombstone Class.
+ */
+class Tombstone {
+	/**
+	 * HTTP codes that indicate a tombstone.
+	 *
+	 * @var array
+	 */
+	private static $codes = array( 404, 410 );
+
+	/**
+	 * Check for Tombstone.
+	 *
+	 * @param string|\WP_Error|array|object $various The various data to check.
+	 *
+	 * @return bool True if the various data is a tombstone.
+	 */
+	public static function check( $various ) {
+		if ( \is_wp_error( $various ) ) {
+			return self::check_wp_error( $various );
+		}
+
+		if ( \is_string( $various ) ) {
+			if ( is_same_domain( $various ) ) {
+				return self::check_local_url( $various );
+			}
+			return self::check_remote_url( $various );
+		}
+
+		if ( \is_array( $various ) ) {
+			return self::check_array( $various );
+		}
+
+		if ( \is_object( $various ) ) {
+			return self::check_object( $various );
+		}
+
+		return false;
+	}
+
+	/**
+	 * Check for remote URL for Tombstone.
+	 *
+	 * @param string $url The URL to check.
+	 *
+	 * @return bool True if the URL is a tombstone.
+	 */
+	public static function check_remote_url( $url ) {
+		/**
+		 * Fires before checking if the URL is a tombstone.
+		 *
+		 * @param string $url The URL to check.
+		 */
+		\do_action( 'activitypub_pre_http_is_tombstone', $url );
+
+		$response = \wp_safe_remote_get( $url, array( 'headers' => array( 'Accept' => 'application/activity+json' ) ) );
+		$code     = \wp_remote_retrieve_response_code( $response );
+
+		if ( in_array( (int) $code, self::$codes, true ) ) {
+			return true;
+		}
+
+		$data = \wp_remote_retrieve_body( $response );
+		$data = \json_decode( $data, true );
+
+		return self::check_array( $data );
+	}
+
+	/**
+	 * Check for local URL for Tombstone.
+	 *
+	 * @param string $url The URL to check.
+	 *
+	 * @return bool True if the URL is a tombstone.
+	 */
+	public static function check_local_url( $url ) {
+		$urls = get_option( 'activitypub_tombstone_urls', array() );
+
+		return in_array( normalize_url( $url ), $urls, true );
+	}
+
+	/**
+	 * Check if the response is a WP_Error.
+	 *
+	 * @param WP_Error $wp_error The response to check.
+	 *
+	 * @return bool True if the response is a WP_Error, false otherwise.
+	 */
+	public static function check_wp_error( $wp_error ) {
+		if ( ! \is_wp_error( $wp_error ) ) {
+			return false;
+		}
+
+		if ( in_array( (int) $wp_error->get_error_code(), self::$codes, true ) ) {
+			return true;
+		}
+
+		return false;
+	}
+
+	/**
+	 * Check if the given array represents a tombstone.
+	 *
+	 * @param array $data The array to check.
+	 *
+	 * @return bool True if the array represents a tombstone, false otherwise.
+	 */
+	public static function check_array( $data ) {
+		if ( ! \is_array( $data ) ) {
+			return false;
+		}
+
+		if ( isset( $data['type'] ) && 'Tombstone' === $data['type'] ) {
+			return true;
+		}
+
+		return false;
+	}
+
+	/**
+	 * Check if the given object represents a tombstone.
+	 *
+	 * @param object $data The object to check.
+	 *
+	 * @return bool True if the object represents a tombstone, false otherwise.
+	 */
+	public static function check_object( $data ) {
+		if ( ! \is_object( $data ) ) {
+			return false;
+		}
+
+		if ( isset( $data->type ) && 'Tombstone' === $data->type ) {
+			return true;
+		}
+
+		if ( $data instanceof Base_Object && 'Tombstone' === $data->get_type() ) {
+			return true;
+		}
+
+		return false;
+	}
+
+	/**
+	 * Bury a URL.
+	 *
+	 * @param string $url The URL to bury.
+	 */
+	public static function bury( $url ) {
+		$urls   = \get_option( 'activitypub_tombstone_urls', array() );
+		$urls[] = normalize_url( $url );
+		$urls   = \array_unique( $urls );
+
+		\update_option( 'activitypub_tombstone_urls', $urls );
+	}
+}

includes/collection/class-followers.php

@@ -7,7 +7,8 @@
 
 namespace Activitypub\Collection;
 
-use function Activitypub\is_tombstone;
+use Activitypub\Tombstone;
+
 use function Activitypub\get_remote_metadata_by_actor;
 
 /**
@@ -42,7 +43,7 @@ class Followers {
 	public static function add_follower( $user_id, $actor ) {
 		$meta = get_remote_metadata_by_actor( $actor );
 
-		if ( is_tombstone( $meta ) ) {
+		if ( Tombstone::check( $meta ) ) {
 			return $meta;
 		}
 

includes/functions.php

@@ -204,15 +204,9 @@ function is_comment() {
  * @return boolean True if HTTP-Code is 410 or 404.
  */
 function is_tombstone( $wp_error ) {
-	if ( ! is_wp_error( $wp_error ) ) {
-		return false;
-	}
-
-	if ( in_array( (int) $wp_error->get_error_code(), array( 404, 410 ), true ) ) {
-		return true;
-	}
+	_deprecated_function( __FUNCTION__, 'unreleased', 'Activitypub\Tombstone::check_wp_error' );
 
-	return false;
+	return Tombstone::check_wp_error( $wp_error );
 }
 
 /**

includes/handler/class-delete.php

@@ -7,7 +7,7 @@
 
 namespace Activitypub\Handler;
 
-use Activitypub\Http;
+use Activitypub\Tombstone;
 use Activitypub\Collection\Actors;
 use Activitypub\Collection\Interactions;
 
@@ -104,7 +104,7 @@ public static function maybe_delete_follower( $activity ) {
 		$follower = Actors::get_remote_by_uri( $activity['actor'] );
 
 		// Verify that Actor is deleted.
-		if ( ! is_wp_error( $follower ) && Http::is_tombstone( $activity['actor'] ) ) {
+		if ( ! is_wp_error( $follower ) && Tombstone::check( $activity['actor'] ) ) {
 			Actors::delete( $follower->ID );
 			self::maybe_delete_interactions( $activity );
 		}
@@ -117,7 +117,7 @@ public static function maybe_delete_follower( $activity ) {
 	 */
 	public static function maybe_delete_interactions( $activity ) {
 		// Verify that Actor is deleted.
-		if ( Http::is_tombstone( $activity['actor'] ) ) {
+		if ( Tombstone::check( $activity['actor'] ) ) {
 			\wp_schedule_single_event(
 				\time(),
 				'activitypub_delete_actor_interactions',
@@ -153,7 +153,7 @@ public static function maybe_delete_interaction( $activity ) {
 
 		$comments = Interactions::get_interaction_by_id( $id );
 
-		if ( $comments && Http::is_tombstone( $id ) ) {
+		if ( $comments && Tombstone::check( $id ) ) {
 			foreach ( $comments as $comment ) {
 				wp_delete_comment( $comment->comment_ID, true );
 			}

templates/tombstone-json.php

@@ -0,0 +1,27 @@
+<?php
+/**
+ * Tombstone JSON template.
+ *
+ * @package Activitypub
+ */
+
+$object = new \Activitypub\Activity\Base_Object();
+$object->set_id( \Activitypub\Query::get_instance()->get_request_url() );
+$object->set_type( 'Tombstone' );
+
+/**
+ * Fires before an ActivityPub object is generated and sent to the client.
+ *
+ * @param object $object The ActivityPub object.
+ */
+\do_action( 'activitypub_json_pre', $object );
+
+\header( 'Content-Type: application/activity+json' );
+echo $object->to_json(); // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
+
+/**
+ * Fires after an ActivityPub object is generated and sent to the client.
+ *
+ * @param object $object The ActivityPub object.
+ */
+\do_action( 'activitypub_json_post', $object );