| 1 |
<?php |
| 2 |
/** |
| 3 |
* WebFinger class file. |
| 4 |
* |
| 5 |
* @package Activitypub |
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*/ |
| 7 |
|
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namespace Activitypub; |
| 9 |
|
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use Activitypub\Activity\Actor; |
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use Activitypub\Collection\Actors; |
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use Activitypub\Collection\Remote_Actors; |
| 13 |
|
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/** |
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* ActivityPub WebFinger Class. |
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* |
| 17 |
* @author Matthias Pfefferle |
| 18 |
* |
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* @see https://webfinger.net/ |
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*/ |
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class Webfinger { |
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/** |
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* Check whether a value looks like an `acct` identifier. |
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* |
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* Accepts any of: |
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* |
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* - `user@host` — bare WebFinger handle. |
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* - `@user@host` — Mastodon display form with a leading `@`. |
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* - `acct:user@host` — full RFC 7565 URI form. |
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* |
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* The host/local-part pattern follows `ACTIVITYPUB_USERNAME_REGEXP`. |
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* |
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* @since 8.3.0 |
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* |
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* @param mixed $value The candidate value. |
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* @return bool True if the value matches the acct identifier pattern. |
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*/ |
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public static function is_acct( $value ) { |
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if ( ! \is_string( $value ) || '' === $value ) { |
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return false; |
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} |
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|
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return (bool) \preg_match( '/^(?:acct:)?@?' . ACTIVITYPUB_USERNAME_REGEXP . '$/i', $value ); |
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} |
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|
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/** |
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* Returns a users WebFinger "resource". |
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* |
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* @param int $user_id The WordPress user id. |
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* |
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* @return string The user-resource. |
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*/ |
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public static function get_user_resource( $user_id ) { |
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$user = Actors::get_by_id( $user_id ); |
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if ( ! $user || is_wp_error( $user ) ) { |
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return ''; |
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} |
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|
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return $user->get_webfinger(); |
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} |
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|
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/** |
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* Resolve a WebFinger resource. |
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* |
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* @param string $uri The WebFinger Resource. |
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* |
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* @return string|\WP_Error The URL or WP_Error. |
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*/ |
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public static function resolve( $uri ) { |
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$data = self::get_data( $uri ); |
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|
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if ( \is_wp_error( $data ) ) { |
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return $data; |
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} |
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|
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if ( ! is_array( $data ) || empty( $data['links'] ) ) { |
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return new \WP_Error( |
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'webfinger_missing_links', |
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__( 'No valid Link elements found.', 'activitypub' ), |
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array( |
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'status' => 400, |
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'data' => $data, |
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) |
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); |
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} |
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|
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foreach ( $data['links'] as $link ) { |
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if ( |
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'self' === $link['rel'] && |
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isset( $link['type'] ) && |
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( |
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'application/activity+json' === $link['type'] || |
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'application/ld+json; profile="https://www.w3.org/ns/activitystreams"' === $link['type'] |
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) |
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) { |
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return $link['href']; |
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} |
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} |
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|
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return new \WP_Error( |
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'webfinger_url_no_activitypub', |
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__( 'The Site supports WebFinger but not ActivityPub', 'activitypub' ), |
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array( |
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'status' => 400, |
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'data' => $data, |
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) |
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); |
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} |
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|
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/** |
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* Transform a URI to an acct <identifier>@<host>. |
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* |
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* @see https://swicg.github.io/activitypub-webfinger/#reverse-discovery |
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* |
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* @param string $uri The URI (acct:, mailto:, http:, https:). |
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* |
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* @return string|\WP_Error Error or acct URI. |
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*/ |
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public static function uri_to_acct( $uri ) { |
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$data = self::get_data( $uri ); |
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|
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if ( is_wp_error( $data ) ) { |
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return $data; |
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} |
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|
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// Check if subject is an acct URI. |
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if ( |
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isset( $data['subject'] ) && |
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\str_starts_with( $data['subject'], 'acct:' ) |
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) { |
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return $data['subject']; |
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} |
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|
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// Search for an acct URI in the aliases. |
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if ( isset( $data['aliases'] ) ) { |
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foreach ( $data['aliases'] as $alias ) { |
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if ( \str_starts_with( $alias, 'acct:' ) ) { |
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return $alias; |
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} |
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} |
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} |
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|
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return new \WP_Error( |
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'webfinger_url_no_acct', |
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__( 'No acct URI found.', 'activitypub' ), |
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array( |
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'status' => 400, |
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'data' => $data, |
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) |
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); |
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} |
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|
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/** |
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* Convert a URI string to an identifier and its host. |
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* Automatically adds acct: if it's missing. |
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* |
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* @param string $url The URI (acct:, mailto:, http:, https:). |
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* |
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* @return \WP_Error|array Error reaction or array with identifier and host as values. |
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*/ |
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public static function get_identifier_and_host( $url ) { |
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if ( ! $url ) { |
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return new \WP_Error( |
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'webfinger_invalid_identifier', |
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__( 'Invalid Identifier', 'activitypub' ), |
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array( |
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'status' => 400, |
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'data' => $url, |
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) |
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); |
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} |
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|
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// Remove leading @. |
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$url = ltrim( $url, '@' ); |
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|
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if ( ! preg_match( '/^([a-zA-Z+]+):/', $url, $match ) ) { |
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$identifier = 'acct:' . $url; |
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$scheme = 'acct'; |
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} else { |
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$identifier = $url; |
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$scheme = $match[1]; |
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} |
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|
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$host = null; |
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|
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switch ( $scheme ) { |
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case 'acct': |
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case 'mailto': |
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case 'xmpp': |
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if ( strpos( $identifier, '@' ) !== false ) { |
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$host = substr( $identifier, strpos( $identifier, '@' ) + 1 ); |
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} |
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break; |
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default: |
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$host = wp_parse_url( $identifier, PHP_URL_HOST ); |
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break; |
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} |
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|
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if ( empty( $host ) ) { |
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return new \WP_Error( |
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'webfinger_invalid_identifier', |
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__( 'Invalid Identifier', 'activitypub' ), |
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array( |
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'status' => 400, |
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'data' => $url, |
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) |
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); |
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} |
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|
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return array( $identifier, $host ); |
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} |
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|
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/** |
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* Get the WebFinger data for a given URI. |
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* |
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* @param string $uri The Identifier: <identifier>@<host> or URI. |
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* |
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* @return \WP_Error|array Error reaction or array with identifier and host as values. |
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*/ |
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public static function get_data( $uri ) { |
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$identifier_and_host = self::get_identifier_and_host( $uri ); |
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|
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if ( is_wp_error( $identifier_and_host ) ) { |
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return $identifier_and_host; |
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} |
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|
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list( $identifier, $host ) = $identifier_and_host; |
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|
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$webfinger_url = sprintf( |
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'https://%s/.well-known/webfinger?resource=%s', |
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$host, |
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\rawurlencode( $identifier ) |
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); |
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|
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// Use Http::get() which handles all caching (success and errors). |
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$response = Http::get( |
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$webfinger_url, |
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array( 'headers' => array( 'Accept' => 'application/jrd+json' ) ), |
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WEEK_IN_SECONDS |
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); |
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|
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if ( \is_wp_error( $response ) ) { |
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return $response; |
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} |
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|
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$body = \wp_remote_retrieve_body( $response ); |
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|
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return \json_decode( $body, true ); |
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} |
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|
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/** |
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* Get the Remote-Follow endpoint for a given URI. |
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* |
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* @param string $uri The WebFinger Resource URI. |
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* |
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* @return string|\WP_Error Error or the Remote-Follow endpoint URI. |
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*/ |
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public static function get_remote_follow_endpoint( $uri ) { |
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return self::get_intent_endpoint( $uri, 'follow', true ); |
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} |
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|
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/** |
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* Generate a cache key for a given URI. |
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* |
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* @param string $uri A WebFinger Resource URI. |
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* |
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* @return string The cache key. |
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*/ |
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public static function generate_cache_key( $uri ) { |
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$uri = ltrim( $uri, '@' ); |
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|
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if ( filter_var( $uri, FILTER_VALIDATE_EMAIL ) ) { |
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$uri = 'acct:' . $uri; |
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} |
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|
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return 'webfinger_' . md5( $uri ); |
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} |
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|
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/** |
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* Infer a shortname from the Actor ID or URL. Used only for fallbacks, |
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* we will try to use what's supplied. |
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* |
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* @param Actor|string $actor_or_uri The Actor or URI. |
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* |
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* @return string Hopefully the name of the Follower. |
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*/ |
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public static function guess( $actor_or_uri ) { |
| 288 |
if ( ! $actor_or_uri instanceof Actor ) { |
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$actor = Remote_Actors::fetch_by_uri( $actor_or_uri ); |
| 290 |
if ( \is_wp_error( $actor ) ) { |
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return extract_name_from_uri( $actor_or_uri ) . '@' . \wp_parse_url( $actor_or_uri, PHP_URL_HOST ); |
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} |
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|
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$actor_or_uri = $actor; |
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} |
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|
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if ( $actor_or_uri->get_preferred_username() ) { |
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return $actor_or_uri->get_preferred_username() . '@' . \wp_parse_url( $actor_or_uri->get_id(), PHP_URL_HOST ); |
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} |
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|
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return extract_name_from_uri( $actor_or_uri->get_id() ) . '@' . \wp_parse_url( $actor_or_uri->get_id(), PHP_URL_HOST ); |
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} |
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|
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/** |
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* Get the Intent endpoint for a given URI and intent. |
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* |
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* @since 8.0.0 |
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* |
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* @see https://codeberg.org/fediverse/fep/src/branch/main/fep/3b86/fep-3b86.md |
| 310 |
* |
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* @param string $uri The WebFinger Resource URI. |
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* @param string $intent The intent to look for. |
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* @param bool $fallback Whether to fallback to the Remote-Follow endpoint. |
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* |
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* @return string|\WP_Error Error or the Intent endpoint URI (may contain `{uri}` placeholder). |
| 316 |
*/ |
| 317 |
public static function get_intent_endpoint( $uri, $intent, $fallback = false ) { |
| 318 |
$data = self::get_data( $uri ); |
| 319 |
|
| 320 |
if ( \is_wp_error( $data ) ) { |
| 321 |
return $data; |
| 322 |
} |
| 323 |
|
| 324 |
if ( empty( $data['links'] ) ) { |
| 325 |
return new \WP_Error( |
| 326 |
'webfinger_missing_links', |
| 327 |
\__( 'No valid Link elements found.', 'activitypub' ), |
| 328 |
array( |
| 329 |
'status' => 400, |
| 330 |
'data' => $data, |
| 331 |
) |
| 332 |
); |
| 333 |
} |
| 334 |
|
| 335 |
// Normalize the links with $rel as key. |
| 336 |
$links = array(); |
| 337 |
|
| 338 |
foreach ( $data['links'] as $link ) { |
| 339 |
if ( isset( $link['rel'] ) && isset( $link['template'] ) ) { |
| 340 |
$links[ \strtolower( $link['rel'] ) ] = $link['template']; |
| 341 |
} |
| 342 |
} |
| 343 |
|
| 344 |
$intent = \sanitize_text_field( $intent ); |
| 345 |
$intent = \strtolower( $intent ); |
| 346 |
|
| 347 |
if ( ! \filter_var( $intent, FILTER_VALIDATE_URL ) ) { |
| 348 |
$intent = 'https://w3id.org/fep/3b86/' . $intent; |
| 349 |
} |
| 350 |
|
| 351 |
if ( isset( $links[ $intent ] ) ) { |
| 352 |
return $links[ $intent ]; |
| 353 |
} |
| 354 |
|
| 355 |
if ( ! $fallback ) { |
| 356 |
return new \WP_Error( |
| 357 |
'webfinger_missing_intent_endpoint', |
| 358 |
\__( 'No valid Intent endpoint found.', 'activitypub' ), |
| 359 |
array( |
| 360 |
'status' => 400, |
| 361 |
'data' => $data, |
| 362 |
) |
| 363 |
); |
| 364 |
} |
| 365 |
|
| 366 |
/* |
| 367 |
* OStatus subscribe URL (deprecated but still widely supported) |
| 368 |
* |
| 369 |
* @see https://ostatus.github.io/spec/OStatus%201.0%20Draft%202.html#anchor10 |
| 370 |
*/ |
| 371 |
if ( isset( $links['http://ostatus.org/schema/1.0/subscribe'] ) ) { |
| 372 |
return $links['http://ostatus.org/schema/1.0/subscribe']; |
| 373 |
} |
| 374 |
|
| 375 |
/* |
| 376 |
* FEP-3b86 Object Intent — the generic "open this object on my home |
| 377 |
* server" link, equivalent to pasting the URL into the home server's |
| 378 |
* search box. Useful when no verb-specific intent is advertised. |
| 379 |
* |
| 380 |
* @see https://codeberg.org/fediverse/fep/src/branch/main/fep/3b86/fep-3b86.md#5-1-object-intent |
| 381 |
*/ |
| 382 |
if ( isset( $links['https://w3id.org/fep/3b86/object'] ) ) { |
| 383 |
return $links['https://w3id.org/fep/3b86/object']; |
| 384 |
} |
| 385 |
|
| 386 |
// Last-resort: construct a Mastodon-compatible authorize_interaction URL. |
| 387 |
$identifier_and_host = self::get_identifier_and_host( $uri ); |
| 388 |
|
| 389 |
if ( \is_wp_error( $identifier_and_host ) ) { |
| 390 |
return new \WP_Error( |
| 391 |
'webfinger_missing_intent_endpoint', |
| 392 |
\__( 'No valid Intent endpoint found.', 'activitypub' ), |
| 393 |
array( |
| 394 |
'status' => 400, |
| 395 |
'data' => $data, |
| 396 |
) |
| 397 |
); |
| 398 |
} |
| 399 |
|
| 400 |
return 'https://' . $identifier_and_host[1] . '/authorize_interaction?uri={uri}'; |
| 401 |
} |
| 402 |
} |
| 403 |
|
