Add like handler (#804)

* Update class-comment.php

* Initial attempt

* Register like handler

* Add support for undoing likes

* add support for announce

and copied basic comment_type support handling from the Webmention plugin

* fix merge issues

* remove C&P issues

* add missing phpdoc

* Disable Announces and Likes by default.

* set ACTIVITYPUB_DISABLE_REACTIONS to false

* refactorings

* fix escaping

* add default object type

* deduplicate code

---------

Co-authored-by: Matthias Pfefferle <pfefferle@users.noreply.github.com>

activitypub.php

@@ -37,6 +37,8 @@ require_once __DIR__ . '/includes/functions.php';
 \defined( 'ACTIVITYPUB_AUTHORIZED_FETCH' ) || \define( 'ACTIVITYPUB_AUTHORIZED_FETCH', false );
 \defined( 'ACTIVITYPUB_DISABLE_REWRITES' ) || \define( 'ACTIVITYPUB_DISABLE_REWRITES', false );
 \defined( 'ACTIVITYPUB_DISABLE_INCOMING_INTERACTIONS' ) || \define( 'ACTIVITYPUB_DISABLE_INCOMING_INTERACTIONS', false );
+// Disable reactions like `Like` and `Accounce` by default
+\defined( 'ACTIVITYPUB_DISABLE_REACTIONS' ) || \define( 'ACTIVITYPUB_DISABLE_REACTIONS', true );
 \defined( 'ACTIVITYPUB_DISABLE_OUTGOING_INTERACTIONS' ) || \define( 'ACTIVITYPUB_DISABLE_OUTGOING_INTERACTIONS', false );
 \defined( 'ACTIVITYPUB_SHARED_INBOX_FEATURE' ) || \define( 'ACTIVITYPUB_SHARED_INBOX_FEATURE', false );
 \defined( 'ACTIVITYPUB_SEND_VARY_HEADER' ) || \define( 'ACTIVITYPUB_SEND_VARY_HEADER', false );

includes/class-comment.php

@@ -19,6 +19,8 @@ class Comment {
 	 * Initialize the class, registering WordPress hooks
 	 */
 	public static function init() {
+		self::register_comment_types();
+
 		\add_filter( 'comment_reply_link', array( self::class, 'comment_reply_link' ), 10, 3 );
 		\add_filter( 'comment_class', array( self::class, 'comment_class' ), 10, 3 );
 		\add_filter( 'get_comment_link', array( self::class, 'remote_comment_link' ), 11, 3 );
@@ -463,4 +465,115 @@ class Comment {
 			);
 		}
 	}
+
+	/**
+	 * Return the registered custom comment types.
+	 *
+	 * @return array The registered custom comment types
+	 */
+	public static function get_comment_types() {
+		global $activitypub_comment_types;
+
+		return $activitypub_comment_types;
+	}
+
+	/**
+	 * Is this a registered comment type
+	 *
+	 * @param string $slug The name of the type
+	 * @return boolean True if registered.
+	 */
+	public static function is_registered_comment_type( $slug ) {
+		$slug = strtolower( $slug );
+		$slug = sanitize_key( $slug );
+
+		return in_array( $slug, array_keys( self::get_comment_types() ), true );
+	}
+
+	/**
+	 * Return the registered custom comment types names.
+	 *
+	 * @return array The registered custom comment type names
+	 */
+	public static function get_comment_type_names() {
+		return array_values( wp_list_pluck( self::get_comment_types(), 'type' ) );
+	}
+
+	/**
+	 * Get a comment type
+	 *
+	 * @param string $type The comment type
+	 *
+	 * @return array The comment type
+	 */
+	public static function get_comment_type( $type ) {
+		$type  = strtolower( $type );
+		$type  = sanitize_key( $type );
+		$types = self::get_comment_types();
+
+		if ( in_array( $type, array_keys( $types ), true ) ) {
+			$type_array = $types[ $type ];
+		} else {
+			$type_array = array();
+		}
+
+		return apply_filters( "activitypub_comment_type_{$type}", $type_array );
+	}
+
+	/**
+	 * Get a comment type attribute
+	 *
+	 * @param string $type The comment type
+	 * @param string $attr The attribute to get
+	 *
+	 * @return mixed The value of the attribute
+	 */
+	public static function get_comment_type_attr( $type, $attr ) {
+		$type_array = self::get_comment_type( $type );
+
+		if ( $type_array && isset( $type_array[ $attr ] ) ) {
+			$value = $type_array[ $attr ];
+		} else {
+			$value = '';
+		}
+
+		return apply_filters( "activitypub_comment_type_{$attr}", $value, $type );
+	}
+
+
+
+	/**
+	 * Register the comment types used by the ActivityPub plugin
+	 *
+	 * @return void
+	 */
+	public static function register_comment_types() {
+		register_comment_type(
+			'announce',
+			array(
+				'label'       => __( 'Reposts', 'activitypub' ),
+				'singular'    => __( 'Repost', 'activitypub' ),
+				'description' => __( 'A repost on the indieweb is a post that is purely a 100% re-publication of another (typically someone else\'s) post.', 'activitypub' ),
+				'icon'        => '♻️',
+				'class'       => 'p-repost',
+				'type'        => 'repost',
+				// translators: %1$s username, %2$s opject format (post, audio, ...), %3$s URL, %4$s domain
+				'excerpt'     => __( '… reposted this!', 'activitypub' ),
+			)
+		);
+
+		register_comment_type(
+			'like',
+			array(
+				'label'       => __( 'Likes', 'activitypub' ),
+				'singular'    => __( 'Like', 'activitypub' ),
+				'description' => __( 'A like is a popular webaction button and in some cases post type on various silos such as Facebook and Instagram.', 'activitypub' ),
+				'icon'        => '👍',
+				'class'       => 'p-like',
+				'type'        => 'like',
+				// translators: %1$s username, %2$s opject format (post, audio, ...), %3$s URL, %4$s domain
+				'excerpt'     => __( '… liked this!', 'activitypub' ),
+			)
+		);
+	}
 }

includes/class-handler.php

@@ -5,6 +5,7 @@ use Activitypub\Handler\Announce;
 use Activitypub\Handler\Create;
 use Activitypub\Handler\Delete;
 use Activitypub\Handler\Follow;
+use Activitypub\Handler\Like;
 use Activitypub\Handler\Undo;
 use Activitypub\Handler\Update;
 
@@ -30,6 +31,10 @@ class Handler {
 		Undo::init();
 		Update::init();
 
+		if ( ! ACTIVITYPUB_DISABLE_REACTIONS ) {
+			Like::init();
+		}
+
 		do_action( 'activitypub_register_handlers' );
 	}
 }

includes/collection/class-interactions.php

@@ -3,6 +3,7 @@ namespace Activitypub\Collection;
 
 use WP_Error;
 use WP_Comment_Query;
+use Activitypub\Comment;
 
 use function Activitypub\object_to_uri;
 use function Activitypub\url_to_commentid;
@@ -13,6 +14,9 @@ use function Activitypub\get_remote_metadata_by_actor;
  * ActivityPub Interactions Collection
  */
 class Interactions {
+	const INSERT = 'insert';
+	const UPDATE = 'update';
+
 	/**
 	 * Add a comment to a post
 	 *
@@ -21,20 +25,15 @@ class Interactions {
 	 * @return array|false The commentdata or false on failure
 	 */
 	public static function add_comment( $activity ) {
-		if (
+		$commentdata = self::activity_to_comment( $activity );
-			! isset( $activity['object'] ) ||
+
-			! isset( $activity['object']['id'] )
+		if ( ! $commentdata || ! isset( $activity['object']['inReplyTo'] ) ) {
-		) {
 			return false;
 		}
 
-		if ( ! isset( $activity['object']['inReplyTo'] ) ) {
+		$in_reply_to       = \esc_url_raw( $activity['object']['inReplyTo'] );
-			return false;
+		$comment_post_id   = \url_to_postid( $in_reply_to );
-		}
+		$parent_comment_id = url_to_commentid( $in_reply_to );
-
-		$in_reply_to        = \esc_url_raw( $activity['object']['inReplyTo'] );
-		$comment_post_id    = \url_to_postid( $in_reply_to );
-		$parent_comment_id  = url_to_commentid( $in_reply_to );
 
 		// save only replys and reactions
 		if ( ! $comment_post_id && $parent_comment_id ) {
@@ -47,58 +46,10 @@ class Interactions {
 			return false;
 		}
 
-		$actor = object_to_uri( $activity['actor'] );
+		$commentdata['comment_post_ID'] = $comment_post_id;
-		$meta  = get_remote_metadata_by_actor( $actor );
+		$commentdata['comment_parent']  = $parent_comment_id ? $parent_comment_id : 0;
 
-		if ( ! $meta || \is_wp_error( $meta ) ) {
+		return self::persist( $commentdata, self::INSERT );
-			return false;
-		}
-
-		$url = object_to_uri( $meta['url'] );
-
-		$commentdata = array(
-			'comment_post_ID' => $comment_post_id,
-			'comment_author' => isset( $meta['name'] ) ? \esc_attr( $meta['name'] ) : \esc_attr( $meta['preferredUsername'] ),
-			'comment_author_url' => \esc_url_raw( $url ),
-			'comment_content' => \addslashes( $activity['object']['content'] ),
-			'comment_type' => 'comment',
-			'comment_author_email' => '',
-			'comment_parent' => $parent_comment_id ? $parent_comment_id : 0,
-			'comment_meta' => array(
-				'source_id'  => \esc_url_raw( $activity['object']['id'] ),
-				'protocol'   => 'activitypub',
-			),
-		);
-
-		if ( isset( $meta['icon']['url'] ) ) {
-			$commentdata['comment_meta']['avatar_url'] = \esc_url_raw( $meta['icon']['url'] );
-		}
-
-		if ( isset( $activity['object']['url'] ) ) {
-			$commentdata['comment_meta']['source_url'] = \esc_url_raw( object_to_uri( $activity['object']['url'] ) );
-		}
-
-		// disable flood control
-		\remove_action( 'check_comment_flood', 'check_comment_flood_db', 10 );
-		// do not require email for AP entries
-		\add_filter( 'pre_option_require_name_email', '__return_false' );
-		// No nonce possible for this submission route
-		\add_filter(
-			'akismet_comment_nonce',
-			function () {
-				return 'inactive';
-			}
-		);
-		\add_filter( 'wp_kses_allowed_html', array( self::class, 'allowed_comment_html' ), 10, 2 );
-
-		$comment = \wp_new_comment( $commentdata, true );
-
-		\remove_filter( 'wp_kses_allowed_html', array( self::class, 'allowed_comment_html' ), 10 );
-		\remove_filter( 'pre_option_require_name_email', '__return_false' );
-		// re-add flood control
-		\add_action( 'check_comment_flood', 'check_comment_flood_db', 10, 4 );
-
-		return $comment;
 	}
 
 	/**
@@ -122,35 +73,54 @@ class Interactions {
 		//found a local comment id
 		$commentdata['comment_author'] = \esc_attr( $meta['name'] ? $meta['name'] : $meta['preferredUsername'] );
 		$commentdata['comment_content'] = \addslashes( $activity['object']['content'] );
-		if ( isset( $meta['icon']['url'] ) ) {
+
-			$commentdata['comment_meta']['avatar_url'] = \esc_url_raw( $meta['icon']['url'] );
+		return self::persist( $commentdata, self::UPDATE );
+	}
+
+	/**
+	 * Adds an incoming Like, Announce, ... as a comment to a post.
+	 *
+	 * @param array  $activity Activity array.
+	 *
+	 * @return array|false      Comment data or `false` on failure.
+	 */
+	public static function add_reaction( $activity ) {
+		$commentdata = self::activity_to_comment( $activity );
+
+		if ( ! $commentdata ) {
+			return false;
 		}
 
-		// disable flood control
+		$url               = object_to_uri( $activity['object'] );
-		\remove_action( 'check_comment_flood', 'check_comment_flood_db', 10 );
+		$comment_post_id   = url_to_postid( $url );
-		// do not require email for AP entries
+		$parent_comment_id = url_to_commentid( $url );
-		\add_filter( 'pre_option_require_name_email', '__return_false' );
-		// No nonce possible for this submission route
-		\add_filter(
-			'akismet_comment_nonce',
-			function () {
-				return 'inactive';
-			}
-		);
-		\add_filter( 'wp_kses_allowed_html', array( self::class, 'allowed_comment_html' ), 10, 2 );
 
-		$state = \wp_update_comment( $commentdata, true );
+		if ( ! $comment_post_id && $parent_comment_id ) {
-
+			$parent_comment  = get_comment( $parent_comment_id );
-		\remove_filter( 'wp_kses_allowed_html', array( self::class, 'allowed_comment_html' ), 10 );
+			$comment_post_id = $parent_comment->comment_post_ID;
-		\remove_filter( 'pre_option_require_name_email', '__return_false' );
-		// re-add flood control
-		\add_action( 'check_comment_flood', 'check_comment_flood_db', 10, 4 );
-
-		if ( 1 === $state ) {
-			return $commentdata;
-		} else {
-			return $state; // Either `false` or a `WP_Error` instance or `0` or `1`!
 		}
+
+		if ( ! $comment_post_id ) {
+			// Not a reply to a post or comment.
+			return false;
+		}
+
+		$type = $activity['type'];
+
+		if ( ! Comment::is_registered_comment_type( $type ) ) {
+			// Not a valid comment type.
+			return false;
+		}
+
+		$comment_type    = Comment::get_comment_type( $type );
+		$comment_content = $comment_type['excerpt'];
+
+		$commentdata['comment_post_ID'] = $comment_post_id;
+		$commentdata['comment_content'] = esc_html( $comment_content );
+		$commentdata['comment_type']    = $comment_type['type'];
+		$commentdata['comment_parent']  = $parent_comment_id ? $parent_comment_id : 0;
+
+		return self::persist( $commentdata, self::INSERT );
 	}
 
 	/**
@@ -244,4 +214,103 @@ class Interactions {
 
 		return $allowed_tags;
 	}
+
+	/**
+	 * Convert an Activity to a WP_Comment
+	 *
+	 * @param array $activity The Activity array
+	 *
+	 * @return array|false The commentdata or false on failure
+	 */
+	public static function activity_to_comment( $activity ) {
+		$comment_content = null;
+		$actor           = object_to_uri( $activity['actor'] );
+		$actor           = get_remote_metadata_by_actor( $actor );
+
+		// check Actor-Meta
+		if ( ! $actor || is_wp_error( $actor ) ) {
+			return false;
+		}
+
+		// check Actor-Name
+		if ( isset( $actor['name'] ) ) {
+			$comment_author = $actor['name'];
+		} elseif ( isset( $actor['preferredUsername'] ) ) {
+			$comment_author = $actor['preferredUsername'];
+		} else {
+			return false;
+		}
+
+		$url = object_to_uri( $actor['url'] );
+
+		if ( ! $url ) {
+			object_to_uri( $actor['id'] );
+		}
+
+		if ( isset( $activity['object']['content'] ) ) {
+			$comment_content = \addslashes( $activity['object']['content'] );
+		}
+
+		$commentdata = array(
+			'comment_author' => \esc_attr( $comment_author ),
+			'comment_author_url' => \esc_url_raw( $url ),
+			'comment_content' => $comment_content,
+			'comment_type' => 'comment',
+			'comment_author_email' => '',
+			'comment_meta' => array(
+				'source_id'  => \esc_url_raw( object_to_uri( $activity['object'] ) ),
+				'protocol'   => 'activitypub',
+			),
+		);
+
+		if ( isset( $actor['icon']['url'] ) ) {
+			$commentdata['comment_meta']['avatar_url'] = \esc_url_raw( $actor['icon']['url'] );
+		}
+
+		if ( isset( $activity['object']['url'] ) ) {
+			$commentdata['comment_meta']['source_url'] = \esc_url_raw( object_to_uri( $activity['object']['url'] ) );
+		}
+
+		return $commentdata;
+	}
+
+	/**
+	 * Persist a comment
+	 *
+	 * @param array  $commentdata The commentdata array
+	 * @param string $action      Either 'insert' or 'update'
+	 *
+	 * @return array|string|int|\WP_Error|false The commentdata or false on failure
+	 */
+	public static function persist( $commentdata, $action = self::INSERT ) {
+		// disable flood control
+		\remove_action( 'check_comment_flood', 'check_comment_flood_db', 10 );
+		// do not require email for AP entries
+		\add_filter( 'pre_option_require_name_email', '__return_false' );
+		// No nonce possible for this submission route
+		\add_filter(
+			'akismet_comment_nonce',
+			function () {
+				return 'inactive';
+			}
+		);
+		\add_filter( 'wp_kses_allowed_html', array( self::class, 'allowed_comment_html' ), 10, 2 );
+
+		if ( self::INSERT === $action ) {
+			$state = \wp_new_comment( $commentdata, true );
+		} else {
+			$state = \wp_update_comment( $commentdata, true );
+		}
+
+		\remove_filter( 'wp_kses_allowed_html', array( self::class, 'allowed_comment_html' ), 10 );
+		\remove_filter( 'pre_option_require_name_email', '__return_false' );
+		// re-add flood control
+		\add_action( 'check_comment_flood', 'check_comment_flood_db', 10, 4 );
+
+		if ( 1 === $state ) {
+			return $commentdata;
+		} else {
+			return $state; // Either `WP_Comment`, `false` or a `WP_Error` instance or `0` or `1`!
+		}
+	}
 }

includes/functions.php

@@ -743,8 +743,13 @@ function object_to_uri( $object ) { // phpcs:ignore Universal.NamingConventions.
 		return $object;
 	}
 
+	$type = 'Object';
+	if ( isset( $object['type'] ) ) {
+		$type = $object['type'];
+	}
+
 	// return part of Object that makes most sense
-	switch ( $object['type'] ) {
+	switch ( $type ) {
 		case 'Link':
 			$object = $object['href'];
 			break;
@@ -1012,6 +1017,39 @@ function custom_large_numbers( $formatted, $number, $decimals ) {
 	return $formatted;
 }
 
+/**
+ * Registers a ActivityPub comment type.
+ *
+ *
+ * @param string $comment_type Key for comment type.
+ * @param array  $args         Arguments.
+ *
+ * @return array The registered Activitypub comment type.
+ */
+function register_comment_type( $comment_type, $args = array() ) {
+	global $activitypub_comment_types;
+
+	if ( ! is_array( $activitypub_comment_types ) ) {
+		$activitypub_comment_types = array();
+	}
+
+	// Sanitize comment type name.
+	$comment_type = sanitize_key( $comment_type );
+
+	$activitypub_comment_types[ $comment_type ] = $args;
+
+	/**
+	 * Fires after a ActivityPub comment type is registered.
+	 *
+	 *
+	 * @param string $comment_type Comment type.
+	 * @param array  $args         Arguments used to register the comment type.
+	 */
+	do_action( 'activitypub_registered_comment_type', $comment_type, $args );
+
+	return $args;
+}
+
 /**
  * Normalize a URL.
  *

includes/handler/class-announce.php

@@ -2,7 +2,10 @@
 namespace Activitypub\Handler;
 
 use Activitypub\Http;
+use Activitypub\Comment;
+use Activitypub\Collection\Interactions;
 
+use function Activitypub\object_to_uri;
 use function Activitypub\is_activity_public;
 
 /**
@@ -45,7 +48,9 @@ class Announce {
 			return;
 		}
 
-		// @todo save the `Announce`-Activity itself
+		if ( ! ACTIVITYPUB_DISABLE_REACTIONS ) {
+			self::maybe_save_announce( $array, $user_id, $activity );
+		}
 
 		if ( is_string( $array['object'] ) ) {
 			$object = Http::get_remote_object( $array['object'] );
@@ -66,4 +71,35 @@ class Announce {
 		\do_action( 'activitypub_inbox', $object, $user_id, $type, $activity );
 		\do_action( "activitypub_inbox_{$type}", $object, $user_id, $activity );
 	}
+
+	/**
+	 * Try to save the Announce
+	 *
+	 * @param array                $array    The activity-object
+	 * @param int                  $user_id  The id of the local blog-user
+	 * @param Activitypub\Activity $activity The activity object
+	 *
+	 * @return void
+	 */
+	public static function maybe_save_announce( $array, $user_id, $activity ) { // phpcs:ignore
+		$url = object_to_uri( $array['object'] );
+
+		if ( empty( $url ) ) {
+			return;
+		}
+
+		$exists = Comment::object_id_to_comment( esc_url_raw( $url ) );
+		if ( $exists ) {
+			return;
+		}
+
+		$state    = Interactions::add_reaction( $array );
+		$reaction = null;
+
+		if ( $state && ! is_wp_error( $state ) ) {
+			$reaction = get_comment( $state );
+		}
+
+		do_action( 'activitypub_handled_announce', $array, $user_id, $state, $reaction );
+	}
 }

includes/handler/class-like.php

@@ -0,0 +1,59 @@
+<?php
+namespace Activitypub\Handler;
+
+use Activitypub\Comment;
+use Activitypub\Collection\Interactions;
+
+use function Activitypub\object_to_uri;
+
+/**
+ * Handle Like requests
+ */
+class Like {
+	/**
+	 * Initialize the class, registering WordPress hooks
+	 */
+	public static function init() {
+		\add_action(
+			'activitypub_inbox_like',
+			array( self::class, 'handle_like' ),
+			10,
+			3
+		);
+	}
+
+	/**
+	 * Handles "Like" requests
+	 *
+	 * @param array                 $array    The Activity array.
+	 * @param int                   $user_id  The ID of the local blog user.
+	 * @param \Activitypub\Activity $activity The Activity object.
+	 *
+	 * @return void
+	 */
+	public static function handle_like( $array, $user_id, $activity = null ) { // phpcs:ignore Universal.NamingConventions.NoReservedKeywordParameterNames.arrayFound,VariableAnalysis.CodeAnalysis.VariableAnalysis.UnusedVariable,Generic.CodeAnalysis.UnusedFunctionParameter.FoundAfterLastUsed
+		if ( ACTIVITYPUB_DISABLE_INCOMING_INTERACTIONS ) {
+			return;
+		}
+
+		$url = object_to_uri( $array['object'] );
+
+		if ( empty( $url ) ) {
+			return;
+		}
+
+		$exists = Comment::object_id_to_comment( esc_url_raw( $url ) );
+		if ( $exists ) {
+			return;
+		}
+
+		$state    = Interactions::add_reaction( $array );
+		$reaction = null;
+
+		if ( $state && ! is_wp_error( $state ) ) {
+			$reaction = get_comment( $state );
+		}
+
+		do_action( 'activitypub_handled_like', $array, $user_id, $state, $reaction );
+	}
+}

includes/handler/class-undo.php

@@ -3,6 +3,7 @@ namespace Activitypub\Handler;
 
 use Activitypub\Collection\Users;
 use Activitypub\Collection\Followers;
+use Activitypub\Comment;
 
 use function Activitypub\object_to_uri;
 
@@ -28,10 +29,16 @@ class Undo {
 	 */
 	public static function handle_undo( $activity ) {
 		if (
-			isset( $activity['object']['type'] ) &&
+			! isset( $activity['object']['type'] ) ||
-			'Follow' === $activity['object']['type'] &&
+			! isset( $activity['object']['object'] )
-			isset( $activity['object']['object'] )
 		) {
+			return;
+		}
+
+		$type = $activity['object']['type'];
+
+		// Handle "Unfollow" requests
+		if ( 'Follow' === $type ) {
 			$user_id = object_to_uri( $activity['object']['object'] );
 			$user = Users::get_by_resource( $user_id );
 
@@ -46,5 +53,23 @@ class Undo {
 
 			Followers::remove_follower( $user_id, $actor );
 		}
+
+		// Handle "Undo" requests for "Like" and "Create" activities
+		if ( in_array( $type, array( 'Like', 'Create', 'Announce' ), true ) ) {
+			if ( ACTIVITYPUB_DISABLE_INCOMING_INTERACTIONS ) {
+				return;
+			}
+
+			$object_id = object_to_uri( $activity['object'] );
+			$comment   = Comment::object_id_to_comment( esc_url_raw( $object_id ) );
+
+			if ( empty( $comment ) ) {
+				return;
+			}
+
+			$state = wp_trash_comment( $comment );
+
+			do_action( 'activitypub_handled_undo', $activity, $user_id, isset( $state ) ? $state : null, null );
+		}
 	}
 }

tests/bootstrap.php

@@ -1,4 +1,5 @@
 <?php
+\define( 'ACTIVITYPUB_DISABLE_REACTIONS', false );
 
 $_tests_dir = \getenv( 'WP_TESTS_DIR' );
 

tests/test-class-activitypub-create-handler.php

@@ -18,7 +18,12 @@ class Test_Activitypub_Create_Handler extends WP_UnitTestCase {
 		);
 		$this->post_permalink = \get_permalink( $this->post_id );
 
-		\add_filter( 'pre_get_remote_metadata_by_actor', array( '\Test_Activitypub_Create_Handler', 'get_remote_metadata_by_actor' ), 0, 2 );
+		\add_filter( 'pre_get_remote_metadata_by_actor', array( get_called_class(), 'get_remote_metadata_by_actor' ), 0, 2 );
+	}
+
+	public function tear_down() {
+		\remove_filter( 'pre_get_remote_metadata_by_actor', array( get_called_class(), 'get_remote_metadata_by_actor' ) );
+		parent::tear_down();
 	}
 
 	public static function get_remote_metadata_by_actor( $value, $actor ) {

tests/test-class-activitypub-followers.php

@@ -52,12 +52,12 @@ class Test_Activitypub_Followers extends WP_UnitTestCase {
 
 	public function set_up() {
 		parent::set_up();
-		add_filter( 'pre_get_remote_metadata_by_actor', array( get_called_class(), 'pre_get_remote_metadata_by_actor' ), 10, 2 );
+		\add_filter( 'pre_get_remote_metadata_by_actor', array( get_called_class(), 'pre_get_remote_metadata_by_actor' ), 10, 2 );
 		_delete_all_posts();
 	}
 
 	public function tear_down() {
-		remove_filter( 'pre_get_remote_metadata_by_actor', array( get_called_class(), 'pre_get_remote_metadata_by_actor' ) );
+		\remove_filter( 'pre_get_remote_metadata_by_actor', array( get_called_class(), 'pre_get_remote_metadata_by_actor' ) );
 		parent::tear_down();
 	}
 

tests/test-class-activitypub-reaction-handler.php

@@ -0,0 +1,83 @@
+<?php
+class Test_Activitypub_Reaction_Handler extends WP_UnitTestCase {
+	public $user_id;
+	public $user_url;
+	public $post_id;
+	public $post_permalink;
+
+	public function set_up() {
+		parent::set_up();
+		$this->user_id = 1;
+		$authordata = \get_userdata( $this->user_id );
+		$this->user_url = $authordata->user_url;
+
+		$this->post_id = \wp_insert_post(
+			array(
+				'post_author' => $this->user_id,
+				'post_content' => 'test',
+			)
+		);
+		$this->post_permalink = \get_permalink( $this->post_id );
+
+		\add_filter( 'pre_get_remote_metadata_by_actor', array( get_called_class(), 'get_remote_metadata_by_actor' ), 0, 2 );
+	}
+
+	public function tear_down() {
+		\remove_filter( 'pre_get_remote_metadata_by_actor', array( get_called_class(), 'get_remote_metadata_by_actor' ) );
+		parent::tear_down();
+	}
+
+	public static function get_remote_metadata_by_actor( $value, $actor ) {
+		return array(
+			'name' => 'Example User',
+			'icon' => array(
+				'url' => 'https://example.com/icon',
+			),
+			'url'  => $actor,
+			'id'   => 'http://example.org/users/example',
+		);
+	}
+
+	public function create_test_object() {
+		return array(
+			'actor' => $this->user_url,
+			'type' => 'Like',
+			'id' => 'https://example.com/id/' . microtime( true ),
+			'to' => [ $this->user_url ],
+			'cc' => [ 'https://www.w3.org/ns/activitystreams#Public' ],
+			'object' => $this->post_permalink,
+		);
+	}
+
+	public function test_handle_like() {
+		$object = $this->create_test_object();
+		Activitypub\Handler\Like::handle_like( $object, $this->user_id );
+
+		$args = array(
+			'type'    => 'like',
+			'post_id' => $this->post_id,
+		);
+
+		$query = new \WP_Comment_Query( $args );
+		$result = $query->comments;
+
+		$this->assertInstanceOf( 'WP_Comment', $result[0] );
+	}
+
+	public function test_handle_announce() {
+		$object = $this->create_test_object();
+		$object['type'] = 'Announce';
+
+		Activitypub\Handler\Announce::handle_announce( $object, $this->user_id );
+
+		$args = array(
+			'type'    => 'repost',
+			'post_id' => $this->post_id,
+		);
+
+		$query = new \WP_Comment_Query( $args );
+		$result = $query->comments;
+
+		$this->assertInstanceOf( 'WP_Comment', $result[0] );
+	}
+}