laipower/wp-content/plugins/activitypub/includes/class-webfinger.php

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<?php
namespace Activitypub;
use WP_Error;
use Activitypub\Collection\Users;
/**
* ActivityPub WebFinger Class
*
* @author Matthias Pfefferle
*
* @see https://webfinger.net/
*/
class Webfinger {
/**
* Returns a users WebFinger "resource"
*
* @param int $user_id The WordPress user id
*
* @return string The user-resource
*/
public static function get_user_resource( $user_id ) {
$user = Users::get_by_id( $user_id );
if ( ! $user || is_wp_error( $user ) ) {
return '';
}
return $user->get_webfinger();
}
/**
* Resolve a WebFinger resource
*
* @param string $uri The WebFinger Resource
*
* @return string|WP_Error The URL or WP_Error
*/
public static function resolve( $uri ) {
$data = self::get_data( $uri );
if ( \is_wp_error( $data ) ) {
return $data;
}
if ( ! is_array( $data ) || empty( $data['links'] ) ) {
return new WP_Error(
'webfinger_missing_links',
__( 'No valid Link elements found.', 'activitypub' ),
array(
'status' => 400,
'data' => $data,
)
);
}
foreach ( $data['links'] as $link ) {
if (
'self' === $link['rel'] &&
(
'application/activity+json' === $link['type'] ||
'application/ld+json; profile="https://www.w3.org/ns/activitystreams"' === $link['type']
)
) {
return $link['href'];
}
}
return new WP_Error(
'webfinger_url_no_activitypub',
__( 'The Site supports WebFinger but not ActivityPub', 'activitypub' ),
array(
'status' => 400,
'data' => $data,
)
);
}
/**
* Transform a URI to an acct <identifier>@<host>
*
* @param string $uri The URI (acct:, mailto:, http:, https:)
*
* @return string|WP_Error Error or acct URI
*/
public static function uri_to_acct( $uri ) {
$data = self::get_data( $uri );
if ( is_wp_error( $data ) ) {
return $data;
}
// check if subject is an acct URI
if (
isset( $data['subject'] ) &&
\str_starts_with( $data['subject'], 'acct:' )
) {
return $data['subject'];
}
// search for an acct URI in the aliases
if ( isset( $data['aliases'] ) ) {
foreach ( $data['aliases'] as $alias ) {
if ( \str_starts_with( $alias, 'acct:' ) ) {
return $alias;
}
}
}
return new WP_Error(
'webfinger_url_no_acct',
__( 'No acct URI found.', 'activitypub' ),
array(
'status' => 400,
'data' => $data,
)
);
}
/**
* Convert a URI string to an identifier and its host.
* Automatically adds acct: if it's missing.
*
* @param string $url The URI (acct:, mailto:, http:, https:)
*
* @return WP_Error|array Error reaction or array with
* identifier and host as values
*/
public static function get_identifier_and_host( $url ) {
if ( ! $url ) {
return new WP_Error(
'webfinger_invalid_identifier',
__( 'Invalid Identifier', 'activitypub' ),
array(
'status' => 400,
'data' => $url,
)
);
}
// remove leading @
$url = ltrim( $url, '@' );
if ( ! preg_match( '/^([a-zA-Z+]+):/', $url, $match ) ) {
$identifier = 'acct:' . $url;
$scheme = 'acct';
} else {
$identifier = $url;
$scheme = $match[1];
}
$host = null;
switch ( $scheme ) {
case 'acct':
case 'mailto':
case 'xmpp':
if ( strpos( $identifier, '@' ) !== false ) {
$host = substr( $identifier, strpos( $identifier, '@' ) + 1 );
}
break;
default:
$host = wp_parse_url( $identifier, PHP_URL_HOST );
break;
}
if ( empty( $host ) ) {
return new WP_Error(
'webfinger_invalid_identifier',
__( 'Invalid Identifier', 'activitypub' ),
array(
'status' => 400,
'data' => $url,
)
);
}
return array( $identifier, $host );
}
/**
* Get the WebFinger data for a given URI
*
* @param string $uri The Identifier: <identifier>@<host> or URI
*
* @return WP_Error|array Error reaction or array with
* identifier and host as values
*/
public static function get_data( $uri ) {
$identifier_and_host = self::get_identifier_and_host( $uri );
if ( is_wp_error( $identifier_and_host ) ) {
return $identifier_and_host;
}
$transient_key = self::generate_cache_key( $uri );
list( $identifier, $host ) = $identifier_and_host;
$data = \get_transient( $transient_key );
if ( $data ) {
return $data;
}
$webfinger_url = sprintf( 'https://%s/.well-known/webfinger?resource=%s', $host, rawurlencode( $identifier ) );
$response = wp_safe_remote_get(
$webfinger_url,
array(
'headers' => array( 'Accept' => 'application/jrd+json' ),
)
);
if ( is_wp_error( $response ) ) {
return new WP_Error(
'webfinger_url_not_accessible',
__( 'The WebFinger Resource is not accessible.', 'activitypub' ),
array(
'status' => 400,
'data' => $webfinger_url,
)
);
}
$body = wp_remote_retrieve_body( $response );
$data = json_decode( $body, true );
\set_transient( $transient_key, $data, WEEK_IN_SECONDS );
return $data;
}
/**
* Get the Remote-Follow endpoint for a given URI
*
* @return string|WP_Error Error or the Remote-Follow endpoint URI.
*/
public static function get_remote_follow_endpoint( $uri ) {
$data = self::get_data( $uri );
if ( is_wp_error( $data ) ) {
return $data;
}
if ( empty( $data['links'] ) ) {
return new WP_Error(
'webfinger_missing_links',
__( 'No valid Link elements found.', 'activitypub' ),
array(
'status' => 400,
'data' => $data,
)
);
}
foreach ( $data['links'] as $link ) {
if ( 'http://ostatus.org/schema/1.0/subscribe' === $link['rel'] ) {
return $link['template'];
}
}
return new WP_Error(
'webfinger_missing_remote_follow_endpoint',
__( 'No valid Remote-Follow endpoint found.', 'activitypub' ),
array(
'status' => 400,
'data' => $data,
)
);
}
/**
* Generate a cache key for a given URI
*
* @param string $uri A WebFinger Resource URI
*
* @return string The cache key
*/
public static function generate_cache_key( $uri ) {
$uri = ltrim( $uri, '@' );
if ( filter_var( $uri, FILTER_VALIDATE_EMAIL ) ) {
$uri = 'acct:' . $uri;
}
return 'webfinger_' . md5( $uri );
}
}