Update handler (#2381)

Author: pfefferle

.github/changelog/2381-from-description

@@ -0,0 +1,4 @@
+Significance: minor
+Type: changed
+
+Refactored activity handling to support multiple recipients per activity, allowing posts and interactions to be linked to several local users at once.

includes/collection/class-posts.php

@@ -28,14 +28,23 @@ class Posts {
 	/**
 	 * Add an object to the collection.
 	 *
-	 * @param array $activity The activity object data.
-	 * @param int   $user_id  The local user ID.
+	 * @param array     $activity   The activity object data.
+	 * @param int|int[] $recipients The id(s) of the local blog-user(s).
 	 *
 	 * @return \WP_Post|\WP_Error The object post or WP_Error on failure.
 	 */
-	public static function add( $activity, $user_id ) {
+	public static function add( $activity, $recipients ) {
+		$recipients      = (array) $recipients;
 		$activity_object = $activity['object'];
-		$actor           = Remote_Actors::fetch_by_uri( object_to_uri( $activity_object['attributedTo'] ) );
+
+		$existing = self::get_by_guid( $activity_object['id'] );
+		// If post exists, call update instead.
+		if ( ! \is_wp_error( $existing ) ) {
+			return self::update( $activity, $recipients );
+		}
+
+		// Post doesn't exist, create new post.
+		$actor = Remote_Actors::fetch_by_uri( object_to_uri( $activity_object['attributedTo'] ) );
 
 		if ( \is_wp_error( $actor ) ) {
 			return $actor;
@@ -49,7 +58,11 @@ public static function add( $activity, $user_id ) {
 		}
 
 		\add_post_meta( $post_id, '_activitypub_remote_actor_id', $actor->ID );
-		\add_post_meta( $post_id, '_activitypub_user_id', $user_id );
+
+		// Add recipients as separate meta entries after post is created.
+		foreach ( $recipients as $user_id ) {
+			self::add_recipient( $post_id, $user_id );
+		}
 
 		self::add_taxonomies( $post_id, $activity_object );
 
@@ -104,12 +117,14 @@ public static function get_by_guid( $guid ) {
 	/**
 	 * Update an object in the collection.
 	 *
-	 * @param array $activity The activity object data.
-	 * @param int   $user_id  The local user ID.
+	 * @param array     $activity   The activity object data.
+	 * @param int|int[] $recipients The id(s) of the local blog-user(s).
 	 *
 	 * @return \WP_Post|\WP_Error The updated object post or WP_Error on failure.
 	 */
-	public static function update( $activity, $user_id ) {
+	public static function update( $activity, $recipients ) {
+		$recipients = (array) $recipients;
+
 		$post = self::get_by_guid( $activity['object']['id'] );
 		if ( \is_wp_error( $post ) ) {
 			return $post;
@@ -123,9 +138,9 @@ public static function update( $activity, $user_id ) {
 			return $post_id;
 		}
 
-		$post_meta = \get_post_meta( $post_id, '_activitypub_user_id', false );
-		if ( \is_array( $post_meta ) && ! \in_array( (string) $user_id, $post_meta, true ) ) {
-			\add_post_meta( $post_id, '_activitypub_user_id', $user_id );
+		// Add new recipients using add_recipient (handles deduplication).
+		foreach ( $recipients as $user_id ) {
+			self::add_recipient( $post_id, $user_id );
 		}
 
 		self::add_taxonomies( $post_id, $activity['object'] );
@@ -250,4 +265,89 @@ public static function get_by_remote_actor_id( $actor_id ) {
 
 		return $query->posts;
 	}
+
+	/**
+	 * Get all recipients for a post.
+	 *
+	 * @param int $post_id The post ID.
+	 *
+	 * @return int[] Array of user IDs who are recipients.
+	 */
+	public static function get_recipients( $post_id ) {
+		// Get all meta values with key '_activitypub_user_id' (single => false).
+		$recipients = \get_post_meta( $post_id, '_activitypub_user_id', false );
+		$recipients = \array_map( 'intval', $recipients );
+
+		return $recipients;
+	}
+
+	/**
+	 * Check if a user is a recipient of a post.
+	 *
+	 * @param int $post_id The post ID.
+	 * @param int $user_id The user ID to check.
+	 *
+	 * @return bool True if user is a recipient, false otherwise.
+	 */
+	public static function has_recipient( $post_id, $user_id ) {
+		$recipients = self::get_recipients( $post_id );
+
+		return \in_array( (int) $user_id, $recipients, true );
+	}
+
+	/**
+	 * Add a recipient to an existing post.
+	 *
+	 * @param int $post_id The post ID.
+	 * @param int $user_id The user ID to add.
+	 *
+	 * @return bool True on success, false on failure.
+	 */
+	public static function add_recipient( $post_id, $user_id ) {
+		$user_id = (int) $user_id;
+		// Allow 0 for blog user, but reject negative values.
+		if ( $user_id < 0 ) {
+			return false;
+		}
+
+		// Check if already a recipient.
+		if ( self::has_recipient( $post_id, $user_id ) ) {
+			return true;
+		}
+
+		// Add new recipient as separate meta entry.
+		return (bool) \add_post_meta( $post_id, '_activitypub_user_id', $user_id, false );
+	}
+
+	/**
+	 * Add multiple recipients to an existing post.
+	 *
+	 * @param int   $post_id  The post ID.
+	 * @param int[] $user_ids The user ID or array of user IDs to add.
+	 */
+	public static function add_recipients( $post_id, $user_ids ) {
+		foreach ( $user_ids as $user_id ) {
+			self::add_recipient( $post_id, $user_id );
+		}
+	}
+
+	/**
+	 * Remove a recipient from a post.
+	 *
+	 * @param int $post_id The post ID.
+	 * @param int $user_id The user ID to remove.
+	 *
+	 * @return bool True on success, false on failure.
+	 */
+	public static function remove_recipient( $post_id, $user_id ) {
+		$user_id = (int) $user_id;
+
+		// Allow 0 for blog user, but reject negative values.
+		if ( $user_id < 0 ) {
+			return false;
+		}
+
+		// Delete the specific meta entry with this value.
+		return \delete_post_meta( $post_id, '_activitypub_user_id', $user_id );
+	}
 }

includes/handler/class-accept.php

@@ -28,10 +28,10 @@ public static function init() {
 	/**
 	 * Handles "Accept" requests.
 	 *
-	 * @param array $accept  The activity-object.
-	 * @param int   $user_id The id of the local blog-user.
+	 * @param array     $accept   The activity-object.
+	 * @param int|int[] $user_ids The id of the local blog-user.
 	 */
-	public static function handle_accept( $accept, $user_id ) {
+	public static function handle_accept( $accept, $user_ids ) {
 		// Validate that there is a Follow Activity.
 		$outbox_post = Outbox::get_by_guid( $accept['object']['id'] );
 
@@ -48,18 +48,19 @@ public static function handle_accept( $accept, $user_id ) {
 			return;
 		}
 
+		$user_id = is_array( $user_ids ) ? reset( $user_ids ) : $user_ids;
 		$result  = Following::accept( $actor_post, $user_id );
 		$success = ! \is_wp_error( $result );
 
 		/**
 		 * Fires after an ActivityPub Accept activity has been handled.
 		 *
-		 * @param array              $accept  The ActivityPub activity data.
-		 * @param int                $user_id The local user ID.
-		 * @param bool               $success True on success, false otherwise.
-		 * @param \WP_Post|\WP_Error $result  The remote actor post or error.
+		 * @param array              $accept   The ActivityPub activity data.
+		 * @param int[]              $user_ids The local user IDs.
+		 * @param bool               $success  True on success, false otherwise.
+		 * @param \WP_Post|\WP_Error $result   The remote actor post or error.
 		 */
-		\do_action( 'activitypub_handled_accept', $accept, $user_id, $success, $result );
+		\do_action( 'activitypub_handled_accept', $accept, (array) $user_ids, $success, $result );
 	}
 
 	/**

includes/handler/class-announce.php

@@ -30,10 +30,10 @@ public static function init() {
 	 * Handles "Announce" requests.
 	 *
 	 * @param array                          $announcement The activity-object.
-	 * @param int                            $user_id      The id of the local blog-user.
+	 * @param int|int[]                      $user_ids     The id(s) of the local blog-user(s).
 	 * @param \Activitypub\Activity\Activity $activity     The activity object.
 	 */
-	public static function handle_announce( $announcement, $user_id, $activity = null ) {
+	public static function handle_announce( $announcement, $user_ids, $activity = null ) {
 		// Check if Activity is public or not.
 		if ( ! is_activity_public( $announcement ) ) {
 			// @todo maybe send email
@@ -45,7 +45,7 @@ public static function handle_announce( $announcement, $user_id, $activity = nul
 			return;
 		}
 
-		self::maybe_save_announce( $announcement, $user_id );
+		self::maybe_save_announce( $announcement, $user_ids );
 
 		if ( is_string( $announcement['object'] ) ) {
 			$object = Http::get_remote_object( $announcement['object'] );
@@ -67,29 +67,29 @@ public static function handle_announce( $announcement, $user_id, $activity = nul
 		 * Fires after an Announce has been received.
 		 *
 		 * @param array                               $object   The object.
-		 * @param int                                 $user_id  The id of the local blog-user.
+		 * @param int[]                               $user_ids The ids of the local blog-users.
 		 * @param string                              $type     The type of the activity.
 		 * @param \Activitypub\Activity\Activity|null $activity The activity object.
 		 */
-		\do_action( 'activitypub_inbox', $object, $user_id, $type, $activity );
+		\do_action( 'activitypub_inbox', $object, (array) $user_ids, $type, $activity );
 
 		/**
 		 * Fires after an Announce of a specific type has been received.
 		 *
 		 * @param array                               $object   The object.
-		 * @param int                                 $user_id  The id of the local blog-user.
+		 * @param int[]                               $user_ids The ids of the local blog-users.
 		 * @param \Activitypub\Activity\Activity|null $activity The activity object.
 		 */
-		\do_action( "activitypub_inbox_{$type}", $object, $user_id, $activity );
+		\do_action( "activitypub_inbox_{$type}", $object, (array) $user_ids, $activity );
 	}
 
 	/**
 	 * Try to save the Announce.
 	 *
-	 * @param array $activity The activity-object.
-	 * @param int   $user_id  The id of the local blog-user.
+	 * @param array     $activity The activity-object.
+	 * @param int|int[] $user_ids The id of the local blog-user.
 	 */
-	public static function maybe_save_announce( $activity, $user_id ) {
+	public static function maybe_save_announce( $activity, $user_ids ) {
 		$url = object_to_uri( $activity );
 
 		if ( empty( $url ) ) {
@@ -118,10 +118,10 @@ public static function maybe_save_announce( $activity, $user_id ) {
 		 * Fires after an ActivityPub Announce activity has been handled.
 		 *
 		 * @param array                            $activity The ActivityPub activity data.
-		 * @param int                              $user_id  The local user ID.
+		 * @param int[]                            $user_ids The local user IDs.
 		 * @param bool                             $success  True on success, false otherwise.
 		 * @param array|string|int|\WP_Error|false $result   The WP_Comment object of the created announce/repost comment, or null if creation failed.
 		 */
-		\do_action( 'activitypub_handled_announce', $activity, $user_id, $success, $result );
+		\do_action( 'activitypub_handled_announce', $activity, (array) $user_ids, $success, $result );
 	}
 }

includes/handler/class-collection-sync.php

@@ -39,10 +39,10 @@ public static function init() {
 	 *
 	 * @see https://codeberg.org/fediverse/fep/src/branch/main/fep/8fcf/fep-8fcf.md
 	 *
-	 * @param array $data    The activity data.
-	 * @param int   $user_id The local user ID.
+	 * @param array     $data     The activity data.
+	 * @param int|int[] $user_ids The user ID(s).
 	 */
-	public static function handle_collection_synchronization( $data, $user_id ) {
+	public static function handle_collection_synchronization( $data, $user_ids ) {
 		if ( empty( $_SERVER['HTTP_COLLECTION_SYNCHRONIZATION'] ) ) {
 			return;
 		}
@@ -87,6 +87,8 @@ public static function handle_collection_synchronization( $data, $user_id ) {
 			return;
 		}
 
+		// Extract the user ID for cache key (collection sync is always for a single user).
+		$user_id   = \is_array( $user_ids ) ? \reset( $user_ids ) : $user_ids;
 		$cache_key = 'activitypub_collection_sync_received_' . $user_id . '_' . md5( $actor_url );
 		if ( false === \get_transient( $cache_key ) ) {
 			$frequency = self::get_frequency();
@@ -101,11 +103,11 @@ public static function handle_collection_synchronization( $data, $user_id ) {
 		 * This allows for async processing of the reconciliation.
 		 *
 		 * @param string $collection_type The collection type (e.g., 'followers', 'following', 'liked').
-		 * @param int    $user_id         The local user ID.
+		 * @param int[]  $user_ids        The local user IDs.
 		 * @param string $actor_url       The remote actor URL.
 		 * @param array  $params          The parsed Collection-Synchronization header parameters.
 		 */
-		\do_action( 'activitypub_collection_sync', $collection_type, $user_id, $actor_url, $params );
+		\do_action( 'activitypub_collection_sync', $collection_type, (array) $user_ids, $actor_url, $params );
 	}
 
 	/**