wordpress-activitypub/includes/rest/class-collection.php

<?php
namespace Activitypub\Rest;

use WP_REST_Server;
use WP_REST_Response;
use Activitypub\Activity\Actor;
use Activitypub\Activity\Base_Object;
use Activitypub\Collection\Users as User_Collection;
use Activitypub\Collection\Replies;

use Activitypub\Transformer\Factory;
use WP_Error;

use function Activitypub\esc_hashtag;
use function Activitypub\is_single_user;
use function Activitypub\get_rest_url_by_path;

/**
 * ActivityPub Collections REST-Class
 *
 * @author Matthias Pfefferle
 *
 * @see https://docs.joinmastodon.org/spec/activitypub/#featured
 * @see https://docs.joinmastodon.org/spec/activitypub/#featuredTags
 */
class Collection {
	/**
	 * Initialize the class, registering WordPress hooks
	 */
	public static function init() {
		self::register_routes();
	}

	/**
	 * Register routes
	 */
	public static function register_routes() {
		\register_rest_route(
			ACTIVITYPUB_REST_NAMESPACE,
			'/(users|actors)/(?P<user_id>[\w\-\.]+)/collections/tags',
			array(
				array(
					'methods'             => WP_REST_Server::READABLE,
					'callback'            => array( self::class, 'tags_get' ),
					'args'                => self::request_parameters(),
					'permission_callback' => '__return_true',
				),
			)
		);

		\register_rest_route(
			ACTIVITYPUB_REST_NAMESPACE,
			'/(users|actors)/(?P<user_id>[\w\-\.]+)/collections/featured',
			array(
				array(
					'methods'             => WP_REST_Server::READABLE,
					'callback'            => array( self::class, 'featured_get' ),
					'args'                => self::request_parameters(),
					'permission_callback' => '__return_true',
				),
			)
		);

		\register_rest_route(
			ACTIVITYPUB_REST_NAMESPACE,
			'/collections/moderators',
			array(
				array(
					'methods'             => WP_REST_Server::READABLE,
					'callback'            => array( self::class, 'moderators_get' ),
					'permission_callback' => '__return_true',
				),
			)
		);

		\register_rest_route(
			ACTIVITYPUB_REST_NAMESPACE,
			'/(?P<type>[\w\-\.]+)s/(?P<id>[\w\-\.]+)/replies',
			array(
				array(
					'methods'             => WP_REST_Server::READABLE,
					'callback'            => array( self::class, 'replies_get' ),
					'args'                => self::request_parameters_for_replies(),
					'permission_callback' => '__return_true',
				),
			)
		);
	}

	/**
	 * The endpoint for replies collections
	 *
	 * @param WP_REST_Request $request The request object.
	 *
	 * @return WP_REST_Response The response object.
	 */
	public static function replies_get( $request ) {
		$type = $request->get_param( 'type' );

		// Get the WordPress object of that "owns" the requested replies.
		switch ( $type ) {
			case 'comment':
				$wp_object = \get_comment( $request->get_param( 'id' ) );
				break;
			case 'post':
			default:
				$wp_object = \get_post( $request->get_param( 'id' ) );
				break;
		}

		if ( ! isset( $wp_object ) || is_wp_error( $wp_object ) ) {
			return new WP_Error(
				'activitypub_replies_collection_does_not_exist',
				\sprintf(
					// translators: %s: The type (post, comment, etc.) for which no replies collection exists.
					\__( 'No reply collection exists for the type %s.', 'activitypub' ),
					$type
				)
			);
		}

		$page = intval( $request->get_param( 'page' ) );

		// If the request parameter page is present get the CollectionPage otherwise the replies collection.
		if ( isset( $page ) ) {
			$response = Replies::get_collection_page( $wp_object, $page );
		} else {
			$response = Replies::get_collection( $wp_object );
		}

		if ( is_wp_error( $response ) ) {
			return $response;
		}

		// Add ActivityPub Context.
		$response = array_merge(
			array( '@context' => Base_Object::JSON_LD_CONTEXT ),
			$response
		);

		return new WP_REST_Response( $response, 200 );
	}

	/**
	 * The Featured Tags endpoint
	 *
	 * @param WP_REST_Request $request The request object.
	 *
	 * @return WP_REST_Response The response object.
	 */
	public static function tags_get( $request ) {
		$user_id = $request->get_param( 'user_id' );
		$user    = User_Collection::get_by_various( $user_id );

		if ( is_wp_error( $user ) ) {
			return $user;
		}

		$number = 4;

		$tags = \get_terms(
			array(
				'taxonomy' => 'post_tag',
				'orderby'  => 'count',
				'order'    => 'DESC',
				'number'   => $number,
			)
		);

		if ( is_wp_error( $tags ) ) {
			$tags = array();
		}

		$response = array(
			'@context'   => Base_Object::JSON_LD_CONTEXT,
			'id'         => get_rest_url_by_path( sprintf( 'actors/%d/collections/tags', $user->get__id() ) ),
			'type'       => 'Collection',
			'totalItems' => is_countable( $tags ) ? count( $tags ) : 0,
			'items'      => array(),
		);

		foreach ( $tags as $tag ) {
			$response['items'][] = array(
				'type' => 'Hashtag',
				'href' => \esc_url( \get_tag_link( $tag ) ),
				'name' => esc_hashtag( $tag->name ),
			);
		}

		$rest_response = new WP_REST_Response( $response, 200 );
		$rest_response->header( 'Content-Type', 'application/activity+json; charset=' . get_option( 'blog_charset' ) );

		return $rest_response;
	}

	/**
	 * Featured posts endpoint
	 *
	 * @param WP_REST_Request $request The request object.
	 *
	 * @return WP_REST_Response The response object.
	 */
	public static function featured_get( $request ) {
		$user_id = $request->get_param( 'user_id' );
		$user    = User_Collection::get_by_various( $user_id );

		if ( is_wp_error( $user ) ) {
			return $user;
		}

		$sticky_posts = \get_option( 'sticky_posts' );

		if ( ! is_single_user() && User_Collection::BLOG_USER_ID === $user->get__id() ) {
			$posts = array();
		} elseif ( $sticky_posts ) {
			$args = array(
				'post__in'            => $sticky_posts,
				'ignore_sticky_posts' => 1,
				'orderby'             => 'date',
				'order'               => 'DESC',
			);

			if ( $user->get__id() > 0 ) {
				$args['author'] = $user->get__id();
			}

			$posts = \get_posts( $args );
		} else {
			$posts = array();
		}

		$response = array(
			'@context'     => Base_Object::JSON_LD_CONTEXT,
			'id'           => get_rest_url_by_path( sprintf( 'actors/%d/collections/featured', $user_id ) ),
			'type'         => 'OrderedCollection',
			'totalItems'   => is_countable( $posts ) ? count( $posts ) : 0,
			'orderedItems' => array(),
		);

		foreach ( $posts as $post ) {
			$transformer = Factory::get_transformer( $post );

			if ( \is_wp_error( $transformer ) ) {
				continue;
			}

			$response['orderedItems'][] = $transformer->to_object()->to_array( false );
		}

		$rest_response = new WP_REST_Response( $response, 200 );
		$rest_response->header( 'Content-Type', 'application/activity+json; charset=' . get_option( 'blog_charset' ) );

		return $rest_response;
	}

	/**
	 * Moderators endpoint
	 *
	 * @param WP_REST_Request $request The request object.
	 *
	 * @return WP_REST_Response The response object.
	 */
	public static function moderators_get( $request ) {
		$response = array(
			'@context'     => Actor::JSON_LD_CONTEXT,
			'id'           => get_rest_url_by_path( 'collections/moderators' ),
			'type'         => 'OrderedCollection',
			'orderedItems' => array(),
		);

		$users = User_Collection::get_collection();

		foreach ( $users as $user ) {
			$response['orderedItems'][] = $user->get_url();
		}

		$rest_response = new WP_REST_Response( $response, 200 );
		$rest_response->header( 'Content-Type', 'application/activity+json; charset=' . get_option( 'blog_charset' ) );

		return $rest_response;
	}

	/**
	 * The supported parameters
	 *
	 * @return array list of parameters
	 */
	public static function request_parameters() {
		$params = array();

		$params['user_id'] = array(
			'required' => true,
			'type'     => 'string',
		);

		return $params;
	}

	/**
	 * The supported parameters
	 *
	 * @return array list of parameters
	 */
	public static function request_parameters_for_replies() {
		$params = array();

		$params['type'] = array(
			'required' => true,
			'type'     => 'string',
			'enum'     => array( 'post', 'comment' ),
		);

		$params['id'] = array(
			'required' => true,
			'type'     => 'string',
		);

		return $params;
	}
}