wordpress-activitypub/integration/class-friends-feed-parser-activitypub.php
2022-11-25 11:05:34 +01:00

295 lines
9.2 KiB
PHP

<?php
/**
* This is the class for integrating ActivityPub into the Friends Plugin.
*
* @since 0.14
*
* @package ActivityPub
* @author Alex Kirk
*/
namespace Activitypub;
class Friends_Feed_Parser_ActivityPub extends \Friends\Feed_Parser {
const SLUG = 'activitypub';
const NAME = 'ActivityPub';
const URL = 'https://www.w3.org/TR/activitypub/';
private $friends_feed;
/**
* Constructor.
*
* @param \Friends\Feed $friends_feed The friends feed
*/
public function __construct( \Friends\Feed $friends_feed ) {
$this->friends_feed = $friends_feed;
\add_action( 'activitypub_inbox_create', array( $this, 'handle_received_activity' ), 10, 2 );
\add_action( 'activitypub_inbox_accept', array( $this, 'handle_received_activity' ), 10, 2 );
\add_action( 'friends_user_feed_activated', array( $this, 'queue_follow_user' ), 10 );
\add_action( 'friends_user_feed_deactivated', array( $this, 'queue_unfollow_user' ), 10 );
\add_action( 'friends_feed_parser_activitypub_follow', array( $this, 'follow_user' ), 10, 2 );
\add_action( 'friends_feed_parser_activitypub_unfollow', array( $this, 'unfollow_user' ), 10, 2 );
\add_filter( 'friends_rewrite_incoming_url', array( $this, 'friends_rewrite_incoming_url' ), 10, 2 );
}
/**
* Determines if this is a supported feed and to what degree we feel it's supported.
*
* @param string $url The url.
* @param string $mime_type The mime type.
* @param string $title The title.
* @param string|null $content The content, it can't be assumed that it's always available.
*
* @return int Return 0 if unsupported, a positive value representing the confidence for the feed, use 10 if you're reasonably confident.
*/
public function feed_support_confidence( $url, $mime_type, $title, $content = null ) {
if ( preg_match( '/^@?[^@]+@((?:[a-z0-9-]+\.)+[a-z]+)$/i', $url ) ) {
return 10;
}
return 0;
}
/**
* Format the feed title and autoselect the posts feed.
*
* @param array $feed_details The feed details.
*
* @return array The (potentially) modified feed details.
*/
public function update_feed_details( $feed_details ) {
$meta = \Activitypub\get_remote_metadata_by_actor( $feed_details['url'] );
if ( ! $meta && is_wp_error( $meta ) ) {
return $meta;
}
if ( isset( $meta['name'] ) ) {
$feed_details['title'] = $meta['name'];
} elseif ( isset( $meta['preferredUsername'] ) ) {
$feed_details['title'] = $meta['preferredUsername'];
}
if ( isset( $meta['id'] ) ) {
$feed_details['url'] = $meta['id'];
}
return $feed_details;
}
/**
* Rewrite a Mastodon style URL @username@server to a URL via webfinger.
*
* @param string $url The URL to filter.
* @param string $incoming_url Potentially a mastodon identifier.
*
* @return <type> ( description_of_the_return_value )
*/
public function friends_rewrite_incoming_url( $url, $incoming_url ) {
if ( preg_match( '/^@?[^@]+@((?:[a-z0-9-]+\.)+[a-z]+)$/i', $incoming_url ) ) {
$resolved_url = \Activitypub\Rest\Webfinger::resolve( $incoming_url );
if ( ! is_wp_error( $resolved_url ) ) {
return $resolved_url;
}
}
return $url;
}
/**
* Discover the feeds available at the URL specified.
*
* @param string $content The content for the URL is already provided here.
* @param string $url The url to search.
*
* @return array A list of supported feeds at the URL.
*/
public function discover_available_feeds( $content, $url ) {
$discovered_feeds = array();
$meta = \Activitypub\get_remote_metadata_by_actor( $url );
if ( $meta && ! is_wp_error( $meta ) ) {
$discovered_feeds[ $meta['id'] ] = array(
'type' => 'application/activity+json',
'rel' => 'self',
'post-format' => 'status',
'parser' => self::SLUG,
'autoselect' => true,
);
}
return $discovered_feeds;
}
/**
* Fetches a feed and returns the processed items.
*
* @param string $url The url.
*
* @return array An array of feed items.
*/
public function fetch_feed( $url ) {
// There is no feed to fetch, we'll receive items via ActivityPub.
return array();
}
/**
* Handles "Create" requests
*
* @param array $object The activity-object
* @param int $user_id The id of the local blog-user
*/
public function handle_received_activity( $object, $user_id ) {
$user_feed = $this->friends_feed->get_user_feed_by_url( $object['actor'] );
if ( is_wp_error( $user_feed ) ) {
$meta = \Activitypub\get_remote_metadata_by_actor( $object['actor'] );
$user_feed = $this->friends_feed->get_user_feed_by_url( $meta['url'] );
if ( is_wp_error( $user_feed ) ) {
// We're not following this user.
return false;
}
}
switch ( $object['type'] ) {
case 'Accept':
// nothing to do.
break;
case 'Create':
$this->handle_incoming_post( $object['object'], $user_feed );
}
return true;
}
/**
* Map the Activity type to a post fomat.
*
* @param string $type The type.
*
* @return string The determined post format.
*/
private function map_type_to_post_format( $type ) {
return 'status';
}
/**
* We received a post for a feed, handle it.
*
* @param array $object The object from ActivityPub.
* @param \Friends\User_Feed $user_feed The user feed.
*/
private function handle_incoming_post( $object, \Friends\User_Feed $user_feed ) {
$item = new \Friends\Feed_Item(
array(
'permalink' => $object['url'],
'content' => $object['content'],
'post_format' => $this->map_type_to_post_format( $object['type'] ),
'date' => $object['published'],
)
);
$this->friends_feed->process_incoming_feed_items( array( $item ), $user_feed );
}
/**
* Prepare to follow the user via a scheduled event.
*
* @param \Friends\User_Feed $user_feed The user feed.
*
* @return bool|WP_Error Whether the event was queued.
*/
public function queue_follow_user( \Friends\User_Feed $user_feed ) {
if ( self::SLUG !== $user_feed->get_parser() ) {
return;
}
$args = array( $user_feed->get_url(), get_current_user_id() );
$unfollow_timestamp = wp_next_scheduled( 'friends_feed_parser_activitypub_unfollow', $args );
if ( $unfollow_timestamp ) {
// If we just unfollowed, we don't want the event to potentially be executed after our follow event.
wp_unschedule_event( $unfollow_timestamp, $args );
}
if ( wp_next_scheduled( 'friends_feed_parser_activitypub_follow', $args ) ) {
return;
}
return \wp_schedule_single_event( \time(), 'friends_feed_parser_activitypub_follow', $args );
}
/**
* Follow a user via ActivityPub at a URL.
*
* @param string $url The url.
* @param int $user_id The current user id.
*/
public function follow_user( $url, $user_id ) {
$meta = \Activitypub\get_remote_metadata_by_actor( $url );
$to = $meta['id'];
$inbox = \Activitypub\get_inbox_by_actor( $to );
$actor = \get_author_posts_url( $user_id );
$activity = new \Activitypub\Model\Activity( 'Follow', \Activitypub\Model\Activity::TYPE_SIMPLE );
$activity->set_to( null );
$activity->set_cc( null );
$activity->set_actor( $actor );
$activity->set_object( $to );
$activity->set_id( $actor . '#follow-' . \preg_replace( '~^https?://~', '', $to ) );
$activity = $activity->to_json();
\Activitypub\safe_remote_post( $inbox, $activity, $user_id );
}
/**
* Prepare to unfollow the user via a scheduled event.
*
* @param \Friends\User_Feed $user_feed The user feed.
*
* @return bool|WP_Error Whether the event was queued.
*/
public function queue_unfollow_user( \Friends\User_Feed $user_feed ) {
if ( self::SLUG !== $user_feed->get_parser() ) {
return false;
}
$args = array( $user_feed->get_url(), get_current_user_id() );
$follow_timestamp = wp_next_scheduled( 'friends_feed_parser_activitypub_follow', $args );
if ( $follow_timestamp ) {
// If we just followed, we don't want the event to potentially be executed after our unfollow event.
wp_unschedule_event( $follow_timestamp, $args );
}
if ( wp_next_scheduled( 'friends_feed_parser_activitypub_unfollow', $args ) ) {
return true;
}
return \wp_schedule_single_event( \time(), 'friends_feed_parser_activitypub_unfollow', $args );
}
/**
* Unfllow a user via ActivityPub at a URL.
*
* @param string $url The url.
* @param int $user_id The current user id.
*/
public function unfollow_user( $url, $user_id ) {
$meta = \Activitypub\get_remote_metadata_by_actor( $url );
$to = $meta['id'];
$inbox = \Activitypub\get_inbox_by_actor( $to );
$actor = \get_author_posts_url( $user_id );
$activity = new \Activitypub\Model\Activity( 'Undo', \Activitypub\Model\Activity::TYPE_SIMPLE );
$activity->set_to( null );
$activity->set_cc( null );
$activity->set_actor( $actor );
$activity->set_object(
array(
'type' => 'Follow',
'actor' => $actor,
'object' => $to,
'id' => $to,
)
);
$activity->set_id( $actor . '#unfollow-' . \preg_replace( '~^https?://~', '', $to ) );
$activity = $activity->to_json();
\Activitypub\safe_remote_post( $inbox, $activity, $user_id );
}
}