activitypub / includes / class-mention.php

class-mention.php in ActivityPub 2.1.0, at includes/class-mention.php

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1	<?php
2	namespace Activitypub;
3
4	use WP_Error;
5	use Activitypub\Webfinger;
6
7	/**
8	* ActivityPub Mention Class
9	*
10	* @author Alex Kirk
11	*/
12	class Mention {
13	/**
14	* Initialize the class, registering WordPress hooks
15	*/
16	public static function init() {
17	\add_filter( 'the_content', array( self::class, 'the_content' ), 99, 1 );
18	\add_filter( 'comment_text', array( self::class, 'the_content' ), 10, 1 );
19	\add_filter( 'activitypub_extract_mentions', array( self::class, 'extract_mentions' ), 99, 2 );
20	}
21
22	/**
23	* Filter to replace the mentions in the content with links
24	*
25	* @param string $the_content the post-content
26	*
27	* @return string the filtered post-content
28	*/
29	public static function the_content( $the_content ) {
30	// small protection against execution timeouts: limit to 1 MB
31	if ( mb_strlen( $the_content ) > MB_IN_BYTES ) {
32	return $the_content;
33	}
34	$tag_stack = array();
35	$protected_tags = array(
36	'pre',
37	'code',
38	'textarea',
39	'style',
40	'a',
41	);
42	$content_with_links = '';
43	$in_protected_tag = false;
44	foreach ( wp_html_split( $the_content ) as $chunk ) {
45	if ( preg_match( '#^<!--[\s\S]*-->$#i', $chunk, $m ) ) {
46	$content_with_links .= $chunk;
47	continue;
48	}
49
50	if ( preg_match( '#^<(/)?([a-z-]+)\b[^>]*>$#i', $chunk, $m ) ) {
51	$tag = strtolower( $m[2] );
52	if ( '/' === $m[1] ) {
53	// Closing tag.
54	$i = array_search( $tag, $tag_stack );
55	// We can only remove the tag from the stack if it is in the stack.
56	if ( false !== $i ) {
57	$tag_stack = array_slice( $tag_stack, 0, $i );
58	}
59	} else {
60	// Opening tag, add it to the stack.
61	$tag_stack[] = $tag;
62	}
63
64	// If we're in a protected tag, the tag_stack contains at least one protected tag string.
65	// The protected tag state can only change when we encounter a start or end tag.
66	$in_protected_tag = array_intersect( $tag_stack, $protected_tags );
67
68	// Never inspect tags.
69	$content_with_links .= $chunk;
70	continue;
71	}
72
73	if ( $in_protected_tag ) {
74	// Don't inspect a chunk inside an inspected tag.
75	$content_with_links .= $chunk;
76	continue;
77	}
78
79	// Only reachable when there is no protected tag in the stack.
80	$content_with_links .= \preg_replace_callback( '/@' . ACTIVITYPUB_USERNAME_REGEXP . '/', array( self::class, 'replace_with_links' ), $chunk );
81	}
82
83	return $content_with_links;
84	}
85
86	/**
87	* A callback for preg_replace to build the user links
88	*
89	* @param array $result the preg_match results
90	*
91	* @return string the final string
92	*/
93	public static function replace_with_links( $result ) {
94	$metadata = get_remote_metadata_by_actor( $result[0] );
95
96	if ( ! empty( $metadata ) && ! is_wp_error( $metadata ) && ! empty( $metadata['url'] ) ) {
97	$username = ltrim( $result[0], '@' );
98	if ( ! empty( $metadata['name'] ) ) {
99	$username = $metadata['name'];
100	}
101	if ( ! empty( $metadata['preferredUsername'] ) ) {
102	$username = $metadata['preferredUsername'];
103	}
104
105	$url = isset( $metadata['url'] ) ? $metadata['url'] : $metadata['id'];
106
107	if ( \is_array( $url ) ) {
108	$url = $url[0];
109	}
110
111	return \sprintf( '<a rel="mention" class="u-url mention" href="%s">@<span>%s</span></a>', esc_url( $url ), esc_html( $username ) );
112	}
113
114	return $result[0];
115	}
116
117	/**
118	* Get the Inboxes for the mentioned Actors
119	*
120	* @param array $mentioned The list of Actors that were mentioned
121	*
122	* @return array The list of Inboxes
123	*/
124	public static function get_inboxes( $mentioned ) {
125	$inboxes = array();
126
127	foreach ( $mentioned as $actor ) {
128	$inbox = self::get_inbox_by_mentioned_actor( $actor );
129
130	if ( ! is_wp_error( $inbox ) && $inbox ) {
131	$inboxes[] = $inbox;
132	}
133	}
134
135	return $inboxes;
136	}
137
138	/**
139	* Get the inbox from the Remote-Profile of a mentioned Actor
140	*
141	* @param string $actor The Actor-URL
142	*
143	* @return string The Inbox-URL
144	*/
145	public static function get_inbox_by_mentioned_actor( $actor ) {
146	$metadata = get_remote_metadata_by_actor( $actor );
147
148	if ( \is_wp_error( $metadata ) ) {
149	return $metadata;
150	}
151
152	if ( isset( $metadata['endpoints'] ) && isset( $metadata['endpoints']['sharedInbox'] ) ) {
153	return $metadata['endpoints']['sharedInbox'];
154	}
155
156	if ( \array_key_exists( 'inbox', $metadata ) ) {
157	return $metadata['inbox'];
158	}
159
160	return new WP_Error( 'activitypub_no_inbox', \__( 'No "Inbox" found', 'activitypub' ), $metadata );
161	}
162
163	/**
164	* Extract the mentions from the post_content.
165	*
166	* @param array $mentions The already found mentions.
167	* @param string $post_content The post content.
168	*
169	* @return mixed The discovered mentions.
170	*/
171	public static function extract_mentions( $mentions, $post_content ) {
172	\preg_match_all( '/@' . ACTIVITYPUB_USERNAME_REGEXP . '/i', $post_content, $matches );
173	foreach ( $matches[0] as $match ) {
174	$link = Webfinger::resolve( $match );
175	if ( ! is_wp_error( $link ) ) {
176	$mentions[ $match ] = $link;
177	}
178	}
179	return $mentions;
180	}
181	}
182