Merge branch 'master' into add/activity-handler

README.md

@@ -2,8 +2,8 @@
 **Contributors:** [automattic](https://profiles.wordpress.org/automattic/), [pfefferle](https://profiles.wordpress.org/pfefferle/), [mediaformat](https://profiles.wordpress.org/mediaformat/), [mattwiebe](https://profiles.wordpress.org/mattwiebe/), [akirk](https://profiles.wordpress.org/akirk/), [jeherve](https://profiles.wordpress.org/jeherve/), [nuriapena](https://profiles.wordpress.org/nuriapena/), [cavalierlife](https://profiles.wordpress.org/cavalierlife/)  
 **Tags:** OStatus, fediverse, activitypub, activitystream  
 **Requires at least:** 4.7  
-**Tested up to:** 6.3  
+**Tested up to:** 6.4  
-**Stable tag:** 1.0.10  
+**Stable tag:** 1.1.0  
 **Requires PHP:** 5.6  
 **License:** MIT  
 **License URI:** http://opensource.org/licenses/MIT  
@@ -105,6 +105,16 @@ Where 'blog' is the path to the subdirectory at which your blog resides.
 
 Project maintained on GitHub at [automattic/wordpress-activitypub](https://github.com/automattic/wordpress-activitypub).
 
+### 1.1.0 ###
+
+* Improved: audio and video attachments are now supported!
+* Improved: better error messages if remote profile is not accessible
+* Improved: PHP 8.1 compatibility
+* Fixed: don't try to parse mentions or hashtags for very large (>1MB) posts to prevent timeouts
+* Fixed: better handling of ISO-639-1 locale codes
+* Improved: more reliable [ap_author], props @uk3
+* Improved: NodeInfo statistics
+
 ### 1.0.10 ###
 
 * Improved: better error messages if remote profile is not accessible

activitypub.php

@@ -3,7 +3,7 @@
  * Plugin Name: ActivityPub
  * Plugin URI: https://github.com/pfefferle/wordpress-activitypub/
  * Description: The ActivityPub protocol is a decentralized social networking protocol based upon the ActivityStreams 2.0 data format.
- * Version: 1.0.10
+ * Version: 1.1.0
  * Author: Matthias Pfefferle & Automattic
  * Author URI: https://automattic.com/
  * License: MIT

includes/class-hashtag.php

@@ -43,6 +43,10 @@ class Hashtag {
 	 * @return string the filtered post-content
 	 */
 	public static function the_content( $the_content ) {
+		// small protection against execution timeouts: limit to 1 MB
+		if ( mb_strlen( $the_content ) > MB_IN_BYTES ) {
+			return $the_content;
+		}
 		$tag_stack = array();
 		$protected_tags = array(
 			'pre',

includes/class-mention.php

@@ -26,6 +26,10 @@ class Mention {
 	 * @return string the filtered post-content
 	 */
 	public static function the_content( $the_content ) {
+		// small protection against execution timeouts: limit to 1 MB
+		if ( mb_strlen( $the_content ) > MB_IN_BYTES ) {
+			return $the_content;
+		}
 		$tag_stack = array();
 		$protected_tags = array(
 			'pre',

includes/class-shortcodes.php

@@ -390,7 +390,8 @@ class Shortcodes {
 			return '';
 		}
 
-		$name = \get_the_author_meta( 'display_name', $item->post_author );
+		$author_id = \get_post_field( 'post_author', $item->ID );
+		$name = \get_the_author_meta( 'display_name', $author_id );
 
 		if ( ! $name ) {
 			return '';
@@ -415,7 +416,8 @@ class Shortcodes {
 			return '';
 		}
 
-		$url = \get_the_author_meta( 'user_url', $item->post_author );
+		$author_id = \get_post_field( 'post_author', $item->ID );
+		$url = \get_the_author_meta( 'user_url', $author_id );
 
 		if ( ! $url ) {
 			return '';

includes/compat.php

@@ -35,3 +35,15 @@ if ( ! function_exists( 'get_self_link' ) ) {
 		return esc_url( apply_filters( 'self_link', set_url_scheme( 'http://' . $host['host'] . $path ) ) );
 	}
 }
+
+if ( ! function_exists( 'is_countable' ) ) {
+	/**
+	 * Polyfill for `is_countable()` function added in PHP 7.3.
+	 *
+	 * @param mixed $value The value to check.
+	 * @return bool True if `$value` is countable, otherwise false.
+	 */
+	function is_countable( $value ) {
+			return is_array( $value ) || $value instanceof \Countable;
+	}
+}

includes/functions.php

@@ -5,6 +5,7 @@ use WP_Error;
 use Activitypub\Http;
 use Activitypub\Activity\Activity;
 use Activitypub\Collection\Followers;
+use Activitypub\Collection\Users;
 
 /**
  * Returns the ActivityPub default JSON-context
@@ -549,3 +550,75 @@ function is_activity_public( $data ) {
 
 	return in_array( 'https://www.w3.org/ns/activitystreams#Public', $recipients, true );
 }
+
+/**
+ * Get active users based on a given duration
+ *
+ * @param int $duration The duration to check in month(s)
+ *
+ * @return int The number of active users
+ */
+function get_active_users( $duration = 1 ) {
+
+	$duration = intval( $duration );
+	$transient_key = sprintf( 'monthly_active_users_%d', $duration );
+	$count = get_transient( $transient_key );
+
+	if ( false === $count ) {
+		global $wpdb;
+		$query = "SELECT COUNT( DISTINCT post_author ) FROM {$wpdb->posts} WHERE post_type = 'post' AND post_status = 'publish' AND post_date <= DATE_SUB( NOW(), INTERVAL %d MONTH )";
+		$query = $wpdb->prepare( $query, $duration );
+		$count = $wpdb->get_var( $query ); // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery
+
+		set_transient( $transient_key, $count, DAY_IN_SECONDS );
+	}
+
+	// if 0 authors where active
+	if ( 0 === $count ) {
+		return 0;
+	}
+
+	// if single user mode
+	if ( is_single_user() ) {
+		return 1;
+	}
+
+	// if blog user is disabled
+	if ( is_user_disabled( Users::BLOG_USER_ID ) ) {
+		return $count;
+	}
+
+	// also count blog user
+	return $count + 1;
+}
+
+/**
+ * Get the total number of users
+ *
+ * @return int The total number of users
+ */
+function get_total_users() {
+	// if single user mode
+	if ( is_single_user() ) {
+		return 1;
+	}
+
+	$users = \get_users(
+		array(
+			'capability__in' => array( 'publish_posts' ),
+		)
+	);
+
+	if ( is_array( $users ) ) {
+		$users = count( $users );
+	} else {
+		$users = 1;
+	}
+
+	// if blog user is disabled
+	if ( is_user_disabled( Users::BLOG_USER_ID ) ) {
+		return $users;
+	}
+
+	return $users + 1;
+}

includes/rest/class-collection.php

@@ -105,7 +105,7 @@ class Collection {
 			'@context'   => Activity::CONTEXT,
 			'id'         => get_rest_url_by_path( sprintf( 'users/%d/collections/tags', $user->get__id() ) ),
 			'type'       => 'Collection',
-			'totalItems' => count( $tags ),
+			'totalItems' => is_countable( $tags ) ? count( $tags ) : 0,
 			'items'      => array(),
 		);
 
@@ -163,7 +163,7 @@ class Collection {
 			'@context'     => Activity::CONTEXT,
 			'id'           => get_rest_url_by_path( sprintf( 'users/%d/collections/featured', $user_id ) ),
 			'type'         => 'OrderedCollection',
-			'totalItems'   => count( $posts ),
+			'totalItems'   => is_countable( $posts ) ? count( $posts ) : 0,
 			'orderedItems' => array(),
 		);
 

includes/rest/class-following.php

@@ -75,7 +75,7 @@ class Following {
 
 		$items = apply_filters( 'activitypub_rest_following', array(), $user ); // phpcs:ignore
 
-		$json->totalItems = count( $items ); // phpcs:ignore
+		$json->totalItems = is_countable( $items ) ? count( $items ) : 0; // phpcs:ignore
 		$json->orderedItems = $items; // phpcs:ignore
 
 		$json->first = $json->partOf; // phpcs:ignore

includes/rest/class-nodeinfo.php

@@ -3,6 +3,8 @@ namespace Activitypub\Rest;
 
 use WP_REST_Response;
 
+use function Activitypub\get_total_users;
+use function Activitypub\get_active_users;
 use function Activitypub\get_rest_url_by_path;
 
 /**
@@ -82,24 +84,14 @@ class Nodeinfo {
 			'version' => \get_bloginfo( 'version' ),
 		);
 
-		$users = \get_users(
-			array(
-				'capability__in' => array( 'publish_posts' ),
-			)
-		);
-
-		if ( is_array( $users ) ) {
-			$users = count( $users );
-		} else {
-			$users = 1;
-		}
-
 		$posts = \wp_count_posts();
 		$comments = \wp_count_comments();
 
 		$nodeinfo['usage'] = array(
 			'users' => array(
-				'total' => $users,
+				'total'          => get_total_users(),
+				'activeMonth'    => get_active_users( '1 month ago' ),
+				'activeHalfyear' => get_active_users( '6 month ago' ),
 			),
 			'localPosts' => (int) $posts->publish,
 			'localComments' => (int) $comments->approved,
@@ -139,24 +131,14 @@ class Nodeinfo {
 			'version' => \get_bloginfo( 'version' ),
 		);
 
-		$users = \get_users(
-			array(
-				'capability__in' => array( 'publish_posts' ),
-			)
-		);
-
-		if ( is_array( $users ) ) {
-			$users = count( $users );
-		} else {
-			$users = 1;
-		}
-
 		$posts = \wp_count_posts();
 		$comments = \wp_count_comments();
 
 		$nodeinfo['usage'] = array(
 			'users' => array(
-				'total' => (int) $users,
+				'total'          => get_total_users(),
+				'activeMonth'    => get_active_users( 1 ),
+				'activeHalfyear' => get_active_users( 6 ),
 			),
 			'localPosts' => (int) $posts->publish,
 			'localComments' => (int) $comments->approved,

includes/transformer/class-post.php

@@ -82,7 +82,7 @@ class Post {
 		$object->set_content( $this->get_content() );
 		$object->set_content_map(
 			array(
-				\strstr( \get_locale(), '_', true ) => $this->get_content(),
+				$this->get_locale() => $this->get_content(),
 			)
 		);
 		$path = sprintf( 'users/%d/followers', intval( $wp_post->post_author ) );
@@ -143,78 +143,65 @@ class Post {
 	}
 
 	/**
-	 * Returns the Image Attachments for this Post, parsed from blocks.
+	 * Generates all Media Attachments for a Post.
-	 * @param int $max_images The maximum number of images to return.
-	 * @param array $image_ids The image IDs to append new IDs to.
 	 *
-	 * @return array The image IDs.
+	 * @return array The Attachments.
-	 */
-	protected function get_block_image_ids( $max_images, $image_ids = [] ) {
-		$blocks = \parse_blocks( $this->wp_post->post_content );
-		return self::get_image_ids_from_blocks( $blocks, $image_ids, $max_images );
-	}
-
-	/**
-	 * Recursively get image IDs from blocks.
-	 * @param array $blocks The blocks to search for image IDs
-	 * @param array $image_ids The image IDs to append new IDs to
-	 * @param int $max_images The maximum number of images to return.
-	 *
-	 * @return array The image IDs.
-	 */
-	protected static function get_image_ids_from_blocks( $blocks, $image_ids, $max_images ) {
-		foreach ( $blocks as $block ) {
-			// recurse into inner blocks
-			if ( ! empty( $block['innerBlocks'] ) ) {
-				$image_ids = self::get_image_ids_from_blocks( $block['innerBlocks'], $image_ids, $max_images );
-			}
-
-			switch ( $block['blockName'] ) {
-				case 'core/image':
-				case 'core/cover':
-					if ( ! empty( $block['attrs']['id'] ) ) {
-						$image_ids[] = $block['attrs']['id'];
-					}
-					break;
-				case 'jetpack/slideshow':
-				case 'jetpack/tiled-gallery':
-					if ( ! empty( $block['attrs']['ids'] ) ) {
-						$image_ids = array_merge( $image_ids, $block['attrs']['ids'] );
-					}
-					break;
-				case 'jetpack/image-compare':
-					if ( ! empty( $block['attrs']['beforeImageId'] ) ) {
-						$image_ids[] = $block['attrs']['beforeImageId'];
-					}
-					if ( ! empty( $block['attrs']['afterImageId'] ) ) {
-						$image_ids[] = $block['attrs']['afterImageId'];
-					}
-					break;
-			}
-
-			// we could be at or over max, stop unneeded work
-			if ( count( $image_ids ) >= $max_images ) {
-				break;
-			}
-		}
-
-		// still need to slice it because one gallery could knock us over the limit
-		return \array_slice( $image_ids, 0, $max_images );
-	}
-
-	/**
-	 * Generates all Image Attachments for a Post.
-	 *
-	 * @return array The Image Attachments.
 	 */
 	protected function get_attachments() {
-		$max_images = intval( \apply_filters( 'activitypub_max_image_attachments', \get_option( 'activitypub_max_image_attachments', ACTIVITYPUB_MAX_IMAGE_ATTACHMENTS ) ) );
+		// Once upon a time we only supported images, but we now support audio/video as well.
+		// We maintain the image-centric naming for backwards compatibility.
+		$max_media = intval( \apply_filters( 'activitypub_max_image_attachments', \get_option( 'activitypub_max_image_attachments', ACTIVITYPUB_MAX_IMAGE_ATTACHMENTS ) ) );
 
-		$images = array();
+		if ( site_supports_blocks() && \has_blocks( $this->wp_post->post_content ) ) {
+			return $this->get_block_attachments( $max_media );
+		}
 
+		return $this->get_classic_editor_images( $max_media );
+	}
+
+	/**
+	 * Get media attachments from blocks. They will be formatted as ActivityPub attachments, not as WP attachments.
+	 *
+	 * @param int $max_media The maximum number of attachments to return.
+	 *
+	 * @return array The attachments.
+	 */
+	protected function get_block_attachments( $max_media ) {
+		// max media can't be negative or zero
+		if ( $max_media <= 0 ) {
+			return array();
+		}
+
+		$id = $this->wp_post->ID;
+
+		$media_ids = array();
+
+		// list post thumbnail first if this post has one
+		if ( \function_exists( 'has_post_thumbnail' ) && \has_post_thumbnail( $id ) ) {
+			$media_ids[] = \get_post_thumbnail_id( $id );
+		}
+
+		if ( $max_media > 0 ) {
+			$blocks = \parse_blocks( $this->wp_post->post_content );
+			$media_ids = self::get_media_ids_from_blocks( $blocks, $media_ids, $max_media );
+		}
+		$media_ids = \array_unique( $media_ids );
+
+		return \array_filter( \array_map( array( self::class, 'wp_attachment_to_activity_attachment' ), $media_ids ) );
+	}
+
+	/**
+	 * Get image attachments from the classic editor.
+	 * Note that audio/video attachments are only supported in the block editor.
+	 *
+	 * @param int $max_images The maximum number of images to return.
+	 *
+	 * @return array The attachments.
+	 */
+	protected function get_classic_editor_images( $max_images ) {
 		// max images can't be negative or zero
 		if ( $max_images <= 0 ) {
-			return $images;
+			return array();
 		}
 
 		$id = $this->wp_post->ID;
@@ -228,12 +215,6 @@ class Post {
 		}
 
 		if ( $max_images > 0 ) {
-			// first try to get images that are actually in the post content
-			if ( site_supports_blocks() && \has_blocks( $this->wp_post->post_content ) ) {
-				$block_image_ids = $this->get_block_image_ids( $max_images, $image_ids );
-				$image_ids = \array_merge( $image_ids, $block_image_ids );
-			} else {
-				// fallback to images attached to the post
 			$query = new \WP_Query(
 				array(
 					'post_parent' => $id,
@@ -251,12 +232,77 @@ class Post {
 				}
 			}
 		}
-		}
-
 		$image_ids = \array_unique( $image_ids );
 
-		// get URLs for each image
+		return \array_filter( \array_map( array( self::class, 'wp_attachment_to_activity_attachment' ), $image_ids ) );
-		foreach ( $image_ids as $id ) {
+	}
+
+	/**
+	 * Recursively get media IDs from blocks.
+	 * @param array $blocks The blocks to search for media IDs
+	 * @param array $media_ids The media IDs to append new IDs to
+	 * @param int $max_media The maximum number of media to return.
+	 *
+	 * @return array The image IDs.
+	 */
+	protected static function get_media_ids_from_blocks( $blocks, $media_ids, $max_media ) {
+
+		foreach ( $blocks as $block ) {
+			// recurse into inner blocks
+			if ( ! empty( $block['innerBlocks'] ) ) {
+				$media_ids = self::get_media_ids_from_blocks( $block['innerBlocks'], $media_ids, $max_media );
+			}
+
+			switch ( $block['blockName'] ) {
+				case 'core/image':
+				case 'core/cover':
+				case 'core/audio':
+				case 'core/video':
+				case 'videopress/video':
+					if ( ! empty( $block['attrs']['id'] ) ) {
+						$media_ids[] = $block['attrs']['id'];
+					}
+					break;
+				case 'jetpack/slideshow':
+				case 'jetpack/tiled-gallery':
+					if ( ! empty( $block['attrs']['ids'] ) ) {
+						$media_ids = array_merge( $media_ids, $block['attrs']['ids'] );
+					}
+					break;
+				case 'jetpack/image-compare':
+					if ( ! empty( $block['attrs']['beforeImageId'] ) ) {
+						$media_ids[] = $block['attrs']['beforeImageId'];
+					}
+					if ( ! empty( $block['attrs']['afterImageId'] ) ) {
+						$media_ids[] = $block['attrs']['afterImageId'];
+					}
+					break;
+			}
+
+			// stop doing unneeded work
+			if ( count( $media_ids ) >= $max_media ) {
+				break;
+			}
+		}
+
+		// still need to slice it because one gallery could knock us over the limit
+		return array_slice( $media_ids, 0, $max_media );
+	}
+
+	/**
+	 * Converts a WordPress Attachment to an ActivityPub Attachment.
+	 *
+	 * @param int $id The Attachment ID.
+	 *
+	 * @return array The ActivityPub Attachment.
+	 */
+	public static function wp_attachment_to_activity_attachment( $id ) {
+		$attachment = array();
+		$mime_type = \get_post_mime_type( $id );
+		$mime_type_parts = \explode( '/', $mime_type );
+		// switching on image/audio/video
+		switch ( $mime_type_parts[0] ) {
+			case 'image':
 				$image_size = 'full';
 
 				/**
@@ -268,28 +314,45 @@ class Post {
 				 */
 				$thumbnail = apply_filters(
 					'activitypub_get_image',
-				$this->get_image( $id, $image_size ),
+					self::get_image( $id, $image_size ),
 					$id,
 					$image_size
 				);
 
 				if ( $thumbnail ) {
-				$mimetype = \get_post_mime_type( $id );
 					$alt   = \get_post_meta( $id, '_wp_attachment_image_alt', true );
 					$image = array(
 						'type'      => 'Image',
 						'url'       => $thumbnail[0],
-					'mediaType' => $mimetype,
+						'mediaType' => $mime_type,
 					);
 
 					if ( $alt ) {
 						$image['name'] = $alt;
 					}
-				$images[] = $image;
+					$attachment = $image;
 				}
+				break;
+
+			case 'audio':
+			case 'video':
+				$attachment = array(
+					'type'      => 'Document',
+					'mediaType' => $mime_type,
+					'url'       => \wp_get_attachment_url( $id ),
+					'name'      => \get_the_title( $id ),
+				);
+				$meta = wp_get_attachment_metadata( $id );
+				// height and width for videos
+				if ( isset( $meta['width'] ) && isset( $meta['height'] ) ) {
+					$attachment['width'] = $meta['width'];
+					$attachment['height'] = $meta['height'];
+				}
+				// @todo: add `icon` support for audio/video attachments. Maybe use post thumbnail?
+				break;
 		}
 
-		return $images;
+		return \apply_filters( 'activitypub_attachment', $attachment, $id );
 	}
 
 	/**
@@ -300,7 +363,7 @@ class Post {
 	 *
 	 * @return array|false Array of image data, or boolean false if no image is available.
 	 */
-	protected function get_image( $id, $image_size = 'full' ) {
+	protected static function get_image( $id, $image_size = 'full' ) {
 		/**
 		 * Hook into the image retrieval process. Before image retrieval.
 		 *
@@ -309,7 +372,7 @@ class Post {
 		 */
 		do_action( 'activitypub_get_image_pre', $id, $image_size );
 
-		$thumbnail = \wp_get_attachment_image_src( $id, $image_size );
+		$image = \wp_get_attachment_image_src( $id, $image_size );
 
 		/**
 		 * Hook into the image retrieval process. After image retrieval.
@@ -319,7 +382,7 @@ class Post {
 		 */
 		do_action( 'activitypub_get_image_post', $id, $image_size );
 
-		return $thumbnail;
+		return $image;
 	}
 
 	/**
@@ -335,6 +398,8 @@ class Post {
 			return \ucfirst( \get_option( 'activitypub_object_type', 'note' ) );
 		}
 
+		// Default to Article.
+		$object_type = 'Article';
 		$post_type = \get_post_type( $this->wp_post );
 		switch ( $post_type ) {
 			case 'post':
@@ -515,4 +580,25 @@ class Post {
 	protected function get_mentions() {
 		return apply_filters( 'activitypub_extract_mentions', array(), $this->wp_post->post_content, $this->wp_post );
 	}
+
+	/**
+	 * Returns the locale of the post.
+	 *
+	 * @return string The locale of the post.
+	 */
+	public function get_locale() {
+		$post_id = $this->wp_post->ID;
+		$lang    = \strtolower( \strtok( \get_locale(), '_-' ) );
+
+		/**
+		 * Filter the locale of the post.
+		 *
+		 * @param string  $lang    The locale of the post.
+		 * @param int     $post_id The post ID.
+		 * @param WP_Post $post    The post object.
+		 *
+		 * @return string The filtered locale of the post.
+		 */
+		return apply_filters( 'activitypub_post_locale', $lang, $post_id, $this->wp_post );
+	}
 }

integration/class-nodeinfo.php

@@ -1,6 +1,9 @@
 <?php
 namespace Activitypub\Integration;
 
+use function Activitypub\get_total_users;
+use function Activitypub\get_active_users;
+
 /**
  * Compatibility with the NodeInfo plugin
  *
@@ -31,6 +34,12 @@ class Nodeinfo {
 			$nodeinfo['protocols']['outbound'][] = 'activitypub';
 		}
 
+		$nodeinfo['usage']['users'] = array(
+			'total'          => get_total_users(),
+			'activeMonth'    => get_active_users( '1 month ago' ),
+			'activeHalfyear' => get_active_users( '6 month ago' ),
+		);
+
 		return $nodeinfo;
 	}
 
@@ -44,6 +53,12 @@ class Nodeinfo {
 	public static function add_nodeinfo2_discovery( $nodeinfo ) {
 		$nodeinfo['protocols'][] = 'activitypub';
 
+		$nodeinfo['usage']['users'] = array(
+			'total'          => get_total_users(),
+			'activeMonth'    => get_active_users( '1 month ago' ),
+			'activeHalfyear' => get_active_users( '6 month ago' ),
+		);
+
 		return $nodeinfo;
 	}
 }

readme.txt

@@ -2,8 +2,8 @@
 Contributors: automattic, pfefferle, mediaformat, mattwiebe, akirk, jeherve, nuriapena, cavalierlife
 Tags: OStatus, fediverse, activitypub, activitystream
 Requires at least: 4.7
-Tested up to: 6.3
+Tested up to: 6.4
-Stable tag: 1.0.10
+Stable tag: 1.1.0
 Requires PHP: 5.6
 License: MIT
 License URI: http://opensource.org/licenses/MIT
@@ -105,6 +105,16 @@ Where 'blog' is the path to the subdirectory at which your blog resides.
 
 Project maintained on GitHub at [automattic/wordpress-activitypub](https://github.com/automattic/wordpress-activitypub).
 
+= 1.1.0 =
+
+* Improved: audio and video attachments are now supported!
+* Improved: better error messages if remote profile is not accessible
+* Improved: PHP 8.1 compatibility
+* Fixed: don't try to parse mentions or hashtags for very large (>1MB) posts to prevent timeouts
+* Fixed: better handling of ISO-639-1 locale codes
+* Improved: more reliable [ap_author], props @uk3
+* Improved: NodeInfo statistics
+
 = 1.0.10 =
 
 * Improved: better error messages if remote profile is not accessible

templates/settings.php

@@ -138,7 +138,7 @@
 					</tr>
 					<tr>
 						<th scope="row">
-							<?php \esc_html_e( 'Number of images', 'activitypub' ); ?>
+							<?php \esc_html_e( 'Media attachments', 'activitypub' ); ?>
 						</th>
 						<td>
 							<input value="<?php echo esc_attr( \get_option( 'activitypub_max_image_attachments', ACTIVITYPUB_MAX_IMAGE_ATTACHMENTS ) ); ?>" name="activitypub_max_image_attachments" id="activitypub_max_image_attachments" type="number" min="0" />
@@ -147,13 +147,20 @@
 								echo \wp_kses(
 									\sprintf(
 										// translators:
-										\__( 'The number of images to attach to posts. Default: <code>%s</code>', 'activitypub' ),
+										\__( 'The number of media (images, audio, video) to attach to posts. Default: <code>%s</code>', 'activitypub' ),
 										\esc_html( ACTIVITYPUB_MAX_IMAGE_ATTACHMENTS )
 									),
 									'default'
 								);
 								?>
 							</p>
+							<p class="description">
+								<em>
+									<?php
+										esc_html_e( 'Note: audio and video attachments are only supported from Block Editor.', 'activitypub' );
+									?>
+								</em>
+							</p>
 						</td>
 					</tr>
 					<tr>