activitypub / includes / functions-post.php

functions-post.php in ActivityPub trunk, at includes/functions-post.php

470 lines 14.9 KB

Raw Download Zip

1	<?php
2	/**
3	* Post functions.
4	*
5	* Functions for working with posts in ActivityPub context.
6	*
7	* @package Activitypub
8	*/
9
10	namespace Activitypub;
11
12	use Activitypub\Collection\Remote_Posts;
13
14	/**
15	* Check whether ActivityPub processing should be skipped for this post.
16	*
17	* Pipeline-level gate. Used by schedulers, transformers, and the outbox to
18	* decide whether a post participates in federation processing at all.
19	*
20	* Intentionally returns `false` for posts that are undergoing a federation
21	* lifecycle transition — e.g., a previously federated post whose visibility
22	* was changed to private, or a previously deleted post that was restored —
23	* so that the Delete or Create activity can still be emitted to notify
24	* remote servers.
25	*
26	* DO NOT use this as a content-exposure gate for REST metadata, block
27	* rendering, content-negotiated frontend JSON, or any other surface that
28	* reveals a post's current content or existence to unauthenticated readers.
29	* Use {@see is_post_publicly_queryable()} for those: it answers the simpler
30	* "is this post currently public?" question with no lifecycle escape hatch.
31	*
32	* @see is_post_publicly_queryable() For the current-visibility gate used by
33	* content-exposure surfaces.
34	*
35	* @param mixed $post The post object or ID.
36	*
37	* @return boolean True if ActivityPub processing should be skipped for this post, false otherwise.
38	*/
39	function is_post_disabled( $post ) {
40	// Refuse empty input so `get_post()` doesn't silently resolve to the global $post.
41	if ( empty( $post ) ) {
42	return true;
43	}
44
45	$post = \get_post( $post );
46
47	if ( ! $post ) {
48	return true;
49	}
50
51	$disabled = ! is_post_publicly_queryable( $post );
52
53	/*
54	* Lifecycle-transition override.
55	*
56	* A previously federated post that has since been moved to any non-
57	* publicly-queryable state (local/private visibility, non-public
58	* status, password-protected, or whose post type no longer supports
59	* federation) still needs the pipeline to run so it can emit a Delete
60	* activity. A post that was deleted but later restored needs the
61	* pipeline to emit Create. In both cases we flip the gate back open
62	* even though the post is not currently publicly queryable.
63	*/
64	$object_state = get_wp_object_state( $post );
65
66	if (
67	ACTIVITYPUB_OBJECT_STATE_DELETED === $object_state \|\|
68	( ACTIVITYPUB_OBJECT_STATE_FEDERATED === $object_state && $disabled )
69	) {
70	$disabled = false;
71	}
72
73	/**
74	* Allow plugins to disable posts for ActivityPub.
75	*
76	* @param boolean $disabled True if the post is disabled, false otherwise.
77	* @param \WP_Post $post The post object.
78	*/
79	return \apply_filters( 'activitypub_is_post_disabled', $disabled, $post );
80	}
81
82	/**
83	* Check whether a post's current content is publicly queryable via ActivityPub.
84	*
85	* Content-exposure gate. Use wherever a post's current content, metadata, or
86	* mere existence could leak to an unauthenticated request. Unlike
87	* {@see is_post_disabled()}, this function ignores the federation lifecycle
88	* state: a post that was federated publicly and has since been made private,
89	* local, trashed, or password-protected returns `false` here, even while its
90	* Delete activity is still pending in the outbox.
91	*
92	* Use for: per-post REST metadata routes (reactions, replies, context,
93	* remote-reply), block server-side render callbacks that expose post
94	* content, content-negotiated frontend JSON. Do NOT use for federation
95	* pipeline decisions — that's what {@see is_post_disabled()} is for.
96	*
97	* A post is publicly queryable when it satisfies ALL of the following:
98	* - `post_status` is `publish` (or a well-defined equivalent: published
99	* attachments inheriting from a public parent, or a preview requested
100	* by a user with edit capability).
101	* - Its `activitypub_content_visibility` meta is neither `local` nor
102	* `private`.
103	* - The post type supports the `activitypub` feature.
104	* - No `post_password` is set.
105	*
106	* @since 8.1.0
107	*
108	* @see is_post_disabled() For the pipeline-level federation gate.
109	*
110	* @param mixed $post The post object or ID.
111	*
112	* @return boolean True if the post is currently publicly queryable, false otherwise.
113	*/
114	function is_post_publicly_queryable( $post ) {
115	/*
116	* Refuse to resolve an empty/zero input through `get_post()`. A bare
117	* `get_post( null )` or `get_post( 0 )` falls back to the global
118	* `$post` during a WordPress loop, which would silently check the
119	* wrong post and potentially leak reactions/replies/metadata for a
120	* looped-over post instead of the one the caller intended.
121	*/
122	if ( empty( $post ) ) {
123	return false;
124	}
125
126	$post = \get_post( $post );
127
128	if ( ! $post ) {
129	return false;
130	}
131
132	$visibility = \get_post_meta( $post->ID, 'activitypub_content_visibility', true );
133	$is_local_or_private = \in_array( $visibility, array( ACTIVITYPUB_CONTENT_VISIBILITY_LOCAL, ACTIVITYPUB_CONTENT_VISIBILITY_PRIVATE ), true );
134
135	/*
136	* An attachment (`inherit` status) inherits its parent's visibility.
137	* Recurse into the parent so the attachment also picks up the parent's
138	* content-visibility meta, password protection, and post-type support,
139	* not just its post_status. Unattached attachments are allowed through.
140	*/
141	$is_attachment_public = 'inherit' === $post->post_status &&
142	'attachment' === $post->post_type &&
143	( ! $post->post_parent \|\| is_post_publicly_queryable( $post->post_parent ) );
144
145	// Draft, pending, and scheduled posts are allowed during preview requests so the Fediverse Preview works.
146	$is_preview = \in_array( $post->post_status, array( 'draft', 'pending', 'future' ), true ) &&
147	\get_query_var( 'preview' ) &&
148	\current_user_can( 'edit_post', $post->ID );
149
150	$is_public_status = 'publish' === $post->post_status \|\| $is_attachment_public \|\| $is_preview;
151
152	$queryable = $is_public_status &&
153	! $is_local_or_private &&
154	\post_type_supports( $post->post_type, 'activitypub' ) &&
155	empty( $post->post_password );
156
157	/**
158	* Filter whether a post is publicly queryable via ActivityPub.
159	*
160	* @since 8.1.0
161	*
162	* @param boolean $queryable True if the post is publicly queryable, false otherwise.
163	* @param \WP_Post $post The post object.
164	*/
165	return \apply_filters( 'activitypub_is_post_publicly_queryable', $queryable, $post );
166	}
167
168	/**
169	* Check whether a post is federated.
170	*
171	* A post is federated when it has been sent to the Fediverse (its federation
172	* state is "federated") AND it is still publicly queryable, i.e. its post type
173	* is enabled for ActivityPub, it has a public status, it is not password-
174	* protected, and its content visibility allows it (see `is_post_publicly_queryable()`).
175	*
176	* Re-checking the live queryability alongside the stored state guards against a
177	* stale "federated" status left behind when a post is moved to a private status,
178	* switched to local visibility, or its post type loses ActivityPub support.
179	*
180	* The federation-state check also keeps `is_post_publicly_queryable()`'s
181	* preview allowance inert here: a draft/pending/scheduled post is never in the
182	* federated state, so the preview branch can never make this return true.
183	*
184	* @since 9.0.0
185	*
186	* @param mixed $post The post ID or object.
187	*
188	* @return boolean True if the post is federated, false otherwise.
189	*/
190	function is_post_federated( $post ) {
191	if ( empty( $post ) ) {
192	return false;
193	}
194
195	$post = \get_post( $post );
196
197	if ( ! $post ) {
198	return false;
199	}
200
201	return ACTIVITYPUB_OBJECT_STATE_FEDERATED === get_wp_object_state( $post ) && is_post_publicly_queryable( $post );
202	}
203
204	/**
205	* Check if a post is an ActivityPub post.
206	*
207	* @param mixed $post The post object or ID.
208	*
209	* @return boolean True if the post is an ActivityPub post, false otherwise.
210	*/
211	function is_ap_post( $post ) {
212	$post = \get_post( $post );
213
214	if ( ! $post ) {
215	return false;
216	}
217
218	// Check for ap_post post type.
219	return Remote_Posts::POST_TYPE === $post->post_type;
220	}
221
222	/**
223	* Get the description of a post type.
224	*
225	* Set some default descriptions for the default post types.
226	*
227	* @param \WP_Post_Type $post_type The post type object.
228	*
229	* @return string The description of the post type.
230	*/
231	function get_post_type_description( $post_type ) {
232	switch ( $post_type->name ) {
233	case 'post':
234	case 'page':
235	$description = '';
236	break;
237	case 'attachment':
238	$description = ' - ' . \__( 'Files uploaded to the media library (such as images, videos, documents, or other attachments). Note: This federates every file upload, not just published content.', 'activitypub' );
239	break;
240	default:
241	$description = '';
242	if ( ! empty( $post_type->description ) ) {
243	$description = ' - ' . $post_type->description;
244	}
245	}
246
247	/**
248	* Allow plugins to get the description of a post type.
249	*
250	* @param string $description The description of the post type.
251	* @param string $post_type_name The post type name.
252	* @param \WP_Post_Type $post_type The post type object.
253	*/
254	return \apply_filters( 'activitypub_post_type_description', $description, $post_type->name, $post_type );
255	}
256
257	/**
258	* Get the maximum number of media attachments a post may federate.
259	*
260	* A per-post limit wins over the site-wide setting, and the filter has the final say.
261	*
262	* @since 9.3.0
263	*
264	* @param int $post_id The post ID.
265	*
266	* @return int The maximum number of media attachments.
267	*/
268	function get_max_attachments( $post_id ) {
269	$max_media = \get_post_meta( $post_id, 'activitypub_max_image_attachments', true );
270
271	if ( ! \is_numeric( $max_media ) ) {
272	$max_media = \get_option( 'activitypub_max_image_attachments', ACTIVITYPUB_MAX_IMAGE_ATTACHMENTS );
273	}
274
275	/**
276	* Filters the maximum number of media attachments allowed in a post.
277	*
278	* Despite the name suggesting only images, this filter controls the maximum number
279	* of all media attachments (images, audio, and video) that can be included in an
280	* ActivityPub post. The name is maintained for backwards compatibility.
281	*
282	* @param int $max_media Maximum number of media attachments. Default ACTIVITYPUB_MAX_IMAGE_ATTACHMENTS.
283	*/
284	return (int) \apply_filters( 'activitypub_max_image_attachments', $max_media );
285	}
286
287	/**
288	* Get the enclosures of a post.
289	*
290	* @param int $post_id The post ID.
291	*
292	* @return array The enclosures.
293	*/
294	function get_enclosures( $post_id ) {
295	$enclosures = \get_post_meta( $post_id, 'enclosure', false );
296
297	if ( ! $enclosures ) {
298	return array();
299	}
300
301	$enclosures = \array_map(
302	static function ( $enclosure ) {
303	// Check if the enclosure is a string.
304	if ( ! $enclosure \|\| ! \is_string( $enclosure ) ) {
305	return false;
306	}
307
308	$attributes = \explode( "\n", $enclosure );
309
310	if ( ! isset( $attributes[0] ) \|\| ! \wp_http_validate_url( $attributes[0] ) ) {
311	return false;
312	}
313
314	return array(
315	'url' => $attributes[0],
316	'length' => $attributes[1] ?? null,
317	'mediaType' => $attributes[2] ?? 'application/octet-stream',
318	);
319	},
320	$enclosures
321	);
322
323	return \array_filter( $enclosures );
324	}
325
326	/**
327	* Generates a summary of a post.
328	*
329	* This function generates a summary based on the post's excerpt or content.
330	*
331	* @param int\|\WP_Post $post The post ID or post object.
332	* @param integer $length The maximum length of the summary.
333	* Default is 500. It will be ignored if the post excerpt
334	* and the content above the <!--more--> tag.
335	*
336	* @return string The generated post summary.
337	*/
338	function generate_post_summary( $post, $length = 500 ) {
339	$post = \get_post( $post );
340
341	if ( ! $post ) {
342	return '';
343	}
344
345	/**
346	* Filters the excerpt more value.
347	*
348	* @param string $excerpt_more The excerpt more.
349	*/
350	$excerpt_more = \apply_filters( 'activitypub_excerpt_more', '[…]' );
351	$length = $length - \mb_strlen( $excerpt_more, 'UTF-8' );
352
353	$content = \sanitize_post_field( 'post_excerpt', $post->post_excerpt, $post->ID );
354
355	if ( $content ) {
356	// Ignore length if excerpt is set.
357	$length = null;
358	} else {
359	$content = \sanitize_post_field( 'post_content', $post->post_content, $post->ID );
360	$content_parts = \get_extended( $content );
361
362	// Check for the <!--more--> tag.
363	if (
364	! empty( $content_parts['extended'] ) &&
365	! empty( $content_parts['main'] )
366	) {
367	$content = \trim( $content_parts['main'] ) . ' ' . $excerpt_more;
368	$length = null;
369	}
370	}
371
372	$content = \strip_shortcodes( $content );
373	$content = \wp_strip_all_tags( $content );
374	$content = \html_entity_decode( $content, ENT_QUOTES, 'UTF-8' );
375	$content = \trim( $content );
376	$content = \preg_replace( '/\R+/mu', "\n\n", $content );
377	$content = \preg_replace( '/[\r\t]/u', '', $content );
378
379	if ( $length && \mb_strlen( $content, 'UTF-8' ) > $length ) {
380	$content = \wordwrap( $content, $length, '</activitypub-summary>' );
381	$content = \explode( '</activitypub-summary>', $content, 2 );
382	$content = $content[0] . ' ' . $excerpt_more;
383	}
384
385	/*
386	There is no proper support for HTML in ActivityPub summaries yet.
387	// This filter is documented in wp-includes/post-template.php.
388	return \apply_filters( 'the_excerpt', $content );
389	*/
390	return $content;
391	}
392
393	/**
394	* Get the content warning of a post.
395	*
396	* @param int\|\WP_Post $post_id The post ID or post object.
397	*
398	* @return string\|false The content warning or false if not found.
399	*/
400	function get_content_warning( $post_id ) {
401	$post = \get_post( $post_id );
402	if ( ! $post ) {
403	return false;
404	}
405
406	$warning = \get_post_meta( $post->ID, 'activitypub_content_warning', true );
407	if ( empty( $warning ) ) {
408	return false;
409	}
410
411	return $warning;
412	}
413
414	/**
415	* Get the ActivityPub ID of a Post by the WordPress Post ID.
416	*
417	* @param int $id The WordPress Post ID.
418	*
419	* @return string The ActivityPub ID (a URL) of the Post.
420	*/
421	function get_post_id( $id ) {
422	$last_legacy_id = (int) \get_option( 'activitypub_last_post_with_permalink_as_id', 0 );
423	$post_id = (int) $id;
424
425	if ( $post_id > $last_legacy_id ) {
426	// Generate URI based on post ID.
427	return \add_query_arg( 'p', $post_id, \home_url( '/' ) );
428	}
429
430	return \get_permalink( $post_id );
431	}
432
433	/**
434	* Get the visibility of a post.
435	*
436	* @param int $post_id The post ID.
437	*
438	* @return string\|false The visibility of the post or false if not found.
439	*/
440	function get_content_visibility( $post_id ) {
441	$post = \get_post( $post_id );
442	if ( ! $post ) {
443	return false;
444	}
445
446	$visibility = \get_post_meta( $post->ID, 'activitypub_content_visibility', true );
447	$_visibility = ACTIVITYPUB_CONTENT_VISIBILITY_PUBLIC;
448	$options = array(
449	ACTIVITYPUB_CONTENT_VISIBILITY_QUIET_PUBLIC,
450	ACTIVITYPUB_CONTENT_VISIBILITY_PRIVATE,
451	ACTIVITYPUB_CONTENT_VISIBILITY_LOCAL,
452	);
453
454	if ( \in_array( $visibility, $options, true ) ) {
455	$_visibility = $visibility;
456	}
457
458	/**
459	* Filters the visibility of a post.
460	*
461	* @param string $_visibility The visibility of the post. Possible values are:
462	* - ACTIVITYPUB_CONTENT_VISIBILITY_PUBLIC
463	* - ACTIVITYPUB_CONTENT_VISIBILITY_QUIET_PUBLIC
464	* - ACTIVITYPUB_CONTENT_VISIBILITY_PRIVATE
465	* - ACTIVITYPUB_CONTENT_VISIBILITY_LOCAL
466	* @param \WP_Post $post The post object.
467	*/
468	return \apply_filters( 'activitypub_content_visibility', $_visibility, $post );
469	}
470