activitypub / includes / class-webfinger.php

class-webfinger.php in ActivityPub 1.3.0, at includes/class-webfinger.php

209 lines 5.3 KB

Raw Download Zip

1	<?php
2	namespace Activitypub;
3
4	use WP_Error;
5	use Activitypub\Collection\Users;
6
7	/**
8	* ActivityPub WebFinger Class
9	*
10	* @author Matthias Pfefferle
11	*
12	* @see https://webfinger.net/
13	*/
14	class Webfinger {
15	/**
16	* Returns a users WebFinger "resource"
17	*
18	* @param int $user_id
19	*
20	* @return string The user-resource
21	*/
22	public static function get_user_resource( $user_id ) {
23	// use WebFinger plugin if installed
24	if ( \function_exists( '\get_webfinger_resource' ) ) {
25	return \get_webfinger_resource( $user_id, false );
26	}
27
28	$user = Users::get_by_id( $user_id );
29	if ( ! $user \|\| is_wp_error( $user ) ) {
30	return '';
31	}
32
33	return $user->get_resource();
34	}
35
36	/**
37	* Resolve a WebFinger resource
38	*
39	* @param string $resource The WebFinger resource
40	*
41	* @return string\|WP_Error The URL or WP_Error
42	*/
43	public static function resolve( $resource ) {
44	if ( ! $resource ) {
45	return null;
46	}
47
48	if ( ! preg_match( '/^@?' . ACTIVITYPUB_USERNAME_REGEXP . '$/i', $resource, $m ) ) {
49	return null;
50	}
51
52	$transient_key = 'activitypub_resolve_' . ltrim( $resource, '@' );
53
54	$link = \get_transient( $transient_key );
55	if ( $link ) {
56	return $link;
57	}
58
59	$url = \add_query_arg( 'resource', 'acct:' . ltrim( $resource, '@' ), 'https://' . $m[2] . '/.well-known/webfinger' );
60	if ( ! \wp_http_validate_url( $url ) ) {
61	$response = new WP_Error( 'invalid_webfinger_url', null, $url );
62	\set_transient( $transient_key, $response, HOUR_IN_SECONDS ); // Cache the error for a shorter period.
63	return $response;
64	}
65
66	// try to access author URL
67	$response = \wp_remote_get(
68	$url,
69	array(
70	'headers' => array( 'Accept' => 'application/jrd+json' ),
71	'redirection' => 2,
72	'timeout' => 2,
73	)
74	);
75
76	if ( \is_wp_error( $response ) ) {
77	$link = new WP_Error( 'webfinger_url_not_accessible', null, $url );
78	\set_transient( $transient_key, $link, HOUR_IN_SECONDS ); // Cache the error for a shorter period.
79	return $link;
80	}
81
82	$body = \wp_remote_retrieve_body( $response );
83	$body = \json_decode( $body, true );
84
85	if ( empty( $body['links'] ) ) {
86	$link = new WP_Error( 'webfinger_url_invalid_response', null, $url );
87	\set_transient( $transient_key, $link, HOUR_IN_SECONDS ); // Cache the error for a shorter period.
88	return $link;
89	}
90
91	foreach ( $body['links'] as $link ) {
92	if ( 'self' === $link['rel'] && 'application/activity+json' === $link['type'] ) {
93	\set_transient( $transient_key, $link['href'], WEEK_IN_SECONDS );
94	return $link['href'];
95	}
96	}
97
98	$link = new WP_Error( 'webfinger_url_no_activitypub', null, $body );
99	\set_transient( $transient_key, $link, HOUR_IN_SECONDS ); // Cache the error for a shorter period.
100	return $link;
101	}
102
103	/**
104	* Convert a URI string to an identifier and its host.
105	* Automatically adds acct: if it's missing.
106	*
107	* @param string $url The URI (acct:, mailto:, http:, https:)
108	*
109	* @return WP_Error\|array Error reaction or array with
110	* identifier and host as values
111	*/
112	public static function get_identifier_and_host( $url ) {
113	// remove leading @
114	$url = ltrim( $url, '@' );
115
116	if ( ! preg_match( '/^([a-zA-Z+]+):/', $url, $match ) ) {
117	$identifier = 'acct:' . $url;
118	$scheme = 'acct';
119	} else {
120	$identifier = $url;
121	$scheme = $match[1];
122	}
123
124	$host = null;
125
126	switch ( $scheme ) {
127	case 'acct':
128	case 'mailto':
129	case 'xmpp':
130	if ( strpos( $identifier, '@' ) !== false ) {
131	$host = substr( $identifier, strpos( $identifier, '@' ) + 1 );
132	}
133	break;
134	default:
135	$host = wp_parse_url( $identifier, PHP_URL_HOST );
136	break;
137	}
138
139	if ( empty( $host ) ) {
140	return new WP_Error( 'invalid_identifier', __( 'Invalid Identifier', 'activitypub' ) );
141	}
142
143	return array( $identifier, $host );
144	}
145
146	/**
147	* Get the WebFinger data for a given URI
148	*
149	* @param string $identifier The Identifier: <identifier>@<host>
150	* @param string $host The Host: <identifier>@<host>
151	*
152	* @return WP_Error\|array Error reaction or array with
153	* identifier and host as values
154	*/
155	public static function get_data( $identifier, $host ) {
156	$webfinger_url = 'https://' . $host . '/.well-known/webfinger?resource=' . rawurlencode( $identifier );
157
158	$response = wp_safe_remote_get(
159	$webfinger_url,
160	array(
161	'headers' => array( 'Accept' => 'application/jrd+json' ),
162	'redirection' => 0,
163	'timeout' => 2,
164	)
165	);
166
167	if ( is_wp_error( $response ) ) {
168	return new WP_Error( 'webfinger_url_not_accessible', null, $webfinger_url );
169	}
170
171	$body = wp_remote_retrieve_body( $response );
172
173	return json_decode( $body, true );
174	}
175
176	/**
177	* Undocumented function
178	*
179	* @return void
180	*/
181	public static function get_remote_follow_endpoint( $uri ) {
182	$identifier_and_host = self::get_identifier_and_host( $uri );
183
184	if ( is_wp_error( $identifier_and_host ) ) {
185	return $identifier_and_host;
186	}
187
188	list( $identifier, $host ) = $identifier_and_host;
189
190	$data = self::get_data( $identifier, $host );
191
192	if ( is_wp_error( $data ) ) {
193	return $data;
194	}
195
196	if ( empty( $data['links'] ) ) {
197	return new WP_Error( 'webfinger_url_invalid_response', null, $data );
198	}
199
200	foreach ( $data['links'] as $link ) {
201	if ( 'http://ostatus.org/schema/1.0/subscribe' === $link['rel'] ) {
202	return $link['template'];
203	}
204	}
205
206	return new WP_Error( 'webfinger_remote_follow_endpoint_invalid', $data, array( 'status' => 417 ) );
207	}
208	}
209