activitypub / includes / class-embed.php

class-embed.php in ActivityPub 7.1.0, at includes/class-embed.php

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1	<?php
2	/**
3	* ActivityPub Embed Handler.
4	*
5	* @package Activitypub
6	*/
7
8	namespace Activitypub;
9
10	/**
11	* Class to handle embedding ActivityPub content
12	*/
13	class Embed {
14
15	/**
16	* Initialize the embed handler
17	*/
18	public static function init() {
19	\add_filter( 'pre_oembed_result', array( self::class, 'maybe_use_activitypub_embed' ), 10, 3 );
20	\add_filter( 'oembed_dataparse', array( self::class, 'handle_filtered_oembed_result' ), 11, 3 );
21	\add_filter( 'oembed_request_post_id', array( self::class, 'register_fallback_hook' ) );
22	}
23
24	/**
25	* Get an ActivityPub embed HTML for a URL.
26	*
27	* @param string $url The URL to get the embed for.
28	* @param boolean $inline_css Whether to inline CSS. Default true.
29	*
30	* @return string\|false The embed HTML or false if not found.
31	*/
32	public static function get_html( $url, $inline_css = true ) {
33	// Try to get ActivityPub representation.
34	$object = Http::get_remote_object( $url );
35
36	if ( \is_wp_error( $object ) \|\| ! is_activity_object( $object ) ) {
37	return false;
38	}
39
40	return self::get_html_for_object( $object, $inline_css );
41	}
42
43	/**
44	* Get an ActivityPub embed HTML for an ActivityPub object.
45	*
46	* @param array $activity_object The ActivityPub object to build the embed for.
47	* @param boolean $inline_css Whether to inline CSS. Default true.
48	*
49	* @return string The embed HTML.
50	*/
51	public static function get_html_for_object( $activity_object, $inline_css = true ) {
52	$author_name = $activity_object['attributedTo'] ?? '';
53	$avatar_url = $activity_object['icon']['url'] ?? '';
54	$author_url = $author_name;
55
56	// If we don't have an avatar URL, but we have an author URL, try to fetch it.
57	if ( ! $avatar_url && $author_url ) {
58	$author = Http::get_remote_object( $author_url );
59	if ( ! is_wp_error( $author ) ) {
60	$avatar_url = $author['icon']['url'] ?? '';
61	$author_name = $author['name'] ?? $author_name;
62	}
63	}
64
65	// Create Webfinger where not found.
66	if ( empty( $author['webfinger'] ) ) {
67	if ( ! empty( $author['preferredUsername'] ) && ! empty( $author['url'] ) ) {
68	// Construct webfinger-style identifier from username and domain.
69	$domain = wp_parse_url( $author['url'], PHP_URL_HOST );
70	$author['webfinger'] = '@' . $author['preferredUsername'] . '@' . $domain;
71	} else {
72	// Fallback to URL.
73	$author['webfinger'] = $author_url;
74	}
75	}
76
77	$title = $activity_object['name'] ?? '';
78	$content = $activity_object['content'] ?? '';
79	$published = isset( $activity_object['published'] ) ? gmdate( get_option( 'date_format' ) . ', ' . get_option( 'time_format' ), strtotime( $activity_object['published'] ) ) : '';
80	$boosts = isset( $activity_object['shares']['totalItems'] ) ? (int) $activity_object['shares']['totalItems'] : null;
81	$favorites = isset( $activity_object['likes']['totalItems'] ) ? (int) $activity_object['likes']['totalItems'] : null;
82
83	$audio = null;
84	$images = array();
85	$video = null;
86	if ( isset( $activity_object['image']['url'] ) ) {
87	$images = array(
88	array(
89	'type' => 'Image',
90	'url' => $activity_object['image']['url'],
91	'name' => $activity_object['image']['name'] ?? '',
92	),
93	);
94	} elseif ( isset( $activity_object['attachment'] ) ) {
95	foreach ( $activity_object['attachment'] as $attachment ) {
96	$type = isset( $attachment['mediaType'] ) ? strtok( $attachment['mediaType'], '/' ) : strtolower( $attachment['type'] );
97
98	switch ( $type ) {
99	case 'image':
100	$images[] = $attachment;
101	break;
102	case 'video':
103	$video = $attachment;
104	break 2;
105	case 'audio':
106	$audio = $attachment;
107	break 2;
108	}
109	}
110	$images = \array_slice( $images, 0, 4 );
111	}
112
113	ob_start();
114	load_template(
115	ACTIVITYPUB_PLUGIN_DIR . 'templates/embed.php',
116	false,
117	array(
118	'audio' => $audio,
119	'author_name' => $author_name,
120	'author_url' => $author_url,
121	'avatar_url' => $avatar_url,
122	'boosts' => $boosts,
123	'content' => $content,
124	'favorites' => $favorites,
125	'images' => $images,
126	'published' => $published,
127	'title' => $title,
128	'url' => $activity_object['id'],
129	'video' => $video,
130	'webfinger' => $author['webfinger'],
131	)
132	);
133
134	if ( $inline_css ) {
135	// Grab the CSS.
136	$css = \file_get_contents( ACTIVITYPUB_PLUGIN_DIR . 'assets/css/activitypub-embed.css' ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents
137	// We embed CSS directly because this may be in an iframe.
138	printf( '<style>%s</style>', $css ); // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
139	}
140
141	// A little light whitespace cleanup.
142	return preg_replace( '/\s+/', ' ', ob_get_clean() );
143	}
144
145	/**
146	* Check if a real oEmbed result exists for the given URL.
147	*
148	* @param string $url The URL to check.
149	* @param array $args Additional arguments passed to wp_oembed_get().
150	* @return bool True if a real oEmbed result exists, false otherwise.
151	*/
152	public static function has_real_oembed( $url, $args = array() ) {
153	// Temporarily remove our filter to avoid infinite loops.
154	\remove_filter( 'pre_oembed_result', array( self::class, 'maybe_use_activitypub_embed' ) );
155
156	// Try to get a "real" oEmbed result. If found, it'll be cached to avoid unnecessary HTTP requests in `wp_oembed_get`.
157	$oembed_result = \wp_oembed_get( $url, $args );
158
159	// Add our filter back.
160	\add_filter( 'pre_oembed_result', array( self::class, 'maybe_use_activitypub_embed' ), 10, 3 );
161
162	return false !== $oembed_result;
163	}
164
165	/**
166	* Filter the oembed result to handle ActivityPub content when no oEmbed is found.
167	* Implementation is a bit weird because there's no way to filter on a false result, we have to use `pre_oembed_result`.
168	*
169	* @param null\|string $result The UNSANITIZED (and potentially unsafe) HTML that should be used to embed.
170	* @param string $url The URL to the content that should be attempted to be embedded.
171	* @param array $args Additional arguments passed to wp_oembed_get().
172	* @return null\|string Return null to allow normal oEmbed processing, or string for ActivityPub embed.
173	*/
174	public static function maybe_use_activitypub_embed( $result, $url, $args ) {
175	// If we already have a result, return it.
176	if ( null !== $result ) {
177	return $result;
178	}
179
180	// If we found a real oEmbed, return null to allow normal processing.
181	if ( self::has_real_oembed( $url, $args ) ) {
182	return null;
183	}
184
185	// No oEmbed found, try to get ActivityPub representation.
186	$html = get_embed_html( $url );
187
188	// If we couldn't get an ActivityPub embed either, return null to allow normal processing.
189	if ( ! $html ) {
190	return null;
191	}
192
193	// Return the ActivityPub embed HTML.
194	return $html;
195	}
196
197	/**
198	* Handle cases where WordPress has filtered out the oEmbed result for security reasons,
199	* but we can provide a safe ActivityPub-specific markup.
200	*
201	* This runs after wp_filter_oembed_result has potentially nullified the result.
202	*
203	* @param string\|false $html The returned oEmbed HTML.
204	* @param object $data A data object result from an oEmbed provider.
205	* @param string $url The URL of the content to be embedded.
206	* @return string\|false The filtered oEmbed HTML or our ActivityPub embed.
207	*/
208	public static function handle_filtered_oembed_result( $html, $data, $url ) {
209	// If we already have valid HTML, return it.
210	if ( $html ) {
211	return $html;
212	}
213
214	// If this isn't a rich or video type, we can't help.
215	if ( ! isset( $data->type ) \|\| ! \in_array( $data->type, array( 'rich', 'video' ), true ) ) {
216	return $html;
217	}
218
219	// If there's no HTML in the data, we can't help.
220	if ( empty( $data->html ) \|\| ! \is_string( $data->html ) ) {
221	return $html;
222	}
223
224	// Try to get ActivityPub representation.
225	$activitypub_html = get_embed_html( $url );
226	if ( ! $activitypub_html ) {
227	return $html;
228	}
229
230	// Return our safer ActivityPub embed HTML.
231	return $activitypub_html;
232	}
233
234	/**
235	* Register the fallback hook for oEmbed requests.
236	*
237	* Avoids filtering every single API request.
238	*
239	* @param int $post_id The post ID.
240	* @return int The post ID.
241	*/
242	public static function register_fallback_hook( $post_id ) {
243	\add_filter( 'rest_request_after_callbacks', array( self::class, 'oembed_fediverse_fallback' ), 10, 3 );
244
245	return $post_id;
246	}
247
248	/**
249	* Fallback for oEmbed requests to the Fediverse.
250	*
251	* @param \WP_REST_Response\|\WP_Error $response Result to send to the client.
252	* @param array $handler Route handler used for the request.
253	* @param \WP_REST_Request $request Request used to generate the response.
254	*
255	* @return \WP_REST_Response\|\WP_Error The response to send to the client.
256	*/
257	public static function oembed_fediverse_fallback( $response, $handler, $request ) {
258	if ( is_wp_error( $response ) && 'oembed_invalid_url' === $response->get_error_code() ) {
259	$url = $request->get_param( 'url' );
260	$html = get_embed_html( $url );
261
262	if ( $html ) {
263	$args = $request->get_params();
264	$data = (object) array(
265	'provider_name' => 'Embed Handler',
266	'html' => $html,
267	'scripts' => array(),
268	);
269
270	/** This filter is documented in wp-includes/class-wp-oembed.php */
271	$data->html = apply_filters( 'oembed_result', $data->html, $url, $args );
272
273	/** This filter is documented in wp-includes/class-wp-oembed-controller.php */
274	$ttl = apply_filters( 'rest_oembed_ttl', DAY_IN_SECONDS, $url, $args );
275
276	set_transient( 'oembed_' . md5( serialize( $args ) ), $data, $ttl ); // phpcs:ignore WordPress.PHP.DiscouragedPHPFunctions.serialize_serialize
277
278	$response = new \WP_REST_Response( $data );
279	}
280	}
281
282	return $response;
283	}
284	}
285