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[friendica.git] / src / Protocol / ActivityPub / Processor.php
1 <?php
2 /**
3  * @copyright Copyright (C) 2010-2022, the Friendica project
4  *
5  * @license GNU AGPL version 3 or any later version
6  *
7  * This program is free software: you can redistribute it and/or modify
8  * it under the terms of the GNU Affero General Public License as
9  * published by the Free Software Foundation, either version 3 of the
10  * License, or (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU Affero General Public License for more details.
16  *
17  * You should have received a copy of the GNU Affero General Public License
18  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
19  *
20  */
21
22 namespace Friendica\Protocol\ActivityPub;
23
24 use Friendica\Content\Text\BBCode;
25 use Friendica\Content\Text\HTML;
26 use Friendica\Content\Text\Markdown;
27 use Friendica\Core\Logger;
28 use Friendica\Core\Protocol;
29 use Friendica\Core\System;
30 use Friendica\Core\Worker;
31 use Friendica\Database\DBA;
32 use Friendica\DI;
33 use Friendica\Model\APContact;
34 use Friendica\Model\Contact;
35 use Friendica\Model\Conversation;
36 use Friendica\Model\Event;
37 use Friendica\Model\GServer;
38 use Friendica\Model\Item;
39 use Friendica\Model\ItemURI;
40 use Friendica\Model\Mail;
41 use Friendica\Model\Tag;
42 use Friendica\Model\User;
43 use Friendica\Model\Post;
44 use Friendica\Protocol\Activity;
45 use Friendica\Protocol\ActivityPub;
46 use Friendica\Protocol\Relay;
47 use Friendica\Util\DateTimeFormat;
48 use Friendica\Util\JsonLD;
49 use Friendica\Util\Strings;
50 use Friendica\Worker\Delivery;
51
52 /**
53  * ActivityPub Processor Protocol class
54  */
55 class Processor
56 {
57         /**
58          * Extracts the tag character (#, @, !) from mention links
59          *
60          * @param string $body
61          * @return string
62          */
63         protected static function normalizeMentionLinks(string $body): string
64         {
65                 return preg_replace('%\[url=([^\[\]]*)]([#@!])(.*?)\[/url]%ism', '$2[url=$1]$3[/url]', $body);
66         }
67
68         /**
69          * Convert the language array into a language JSON
70          *
71          * @param array $languages
72          * @return string language JSON
73          */
74         private static function processLanguages(array $languages): string
75         {
76                 $codes = array_keys($languages);
77                 $lang = [];
78                 foreach ($codes as $code) {
79                         $lang[$code] = 1;
80                 }
81
82                 if (empty($lang)) {
83                         return '';
84                 }
85
86                 return json_encode($lang);
87         }
88         /**
89          * Replaces emojis in the body
90          *
91          * @param int $uri_id
92          * @param string $body
93          * @param array $emojis
94          *
95          * @return string with replaced emojis
96          */
97         private static function replaceEmojis(int $uri_id, string $body, array $emojis): string
98         {
99                 $body = strtr($body,
100                         array_combine(
101                                 array_column($emojis, 'name'),
102                                 array_map(function ($emoji) {
103                                         return '[emoji=' . $emoji['href'] . ']' . $emoji['name'] . '[/emoji]';
104                                 }, $emojis)
105                         )
106                 );
107
108                 // We store the emoji here to be able to avoid storing it in the media
109                 foreach ($emojis as $emoji) {
110                         Post\Link::getByLink($uri_id, $emoji['href']);
111                 }
112                 return $body;
113         }
114
115         /**
116          * Store attached media files in the post-media table
117          *
118          * @param int $uriid
119          * @param array $attachment
120          * @return void
121          */
122         private static function storeAttachmentAsMedia(int $uriid, array $attachment)
123         {
124                 if (empty($attachment['url'])) {
125                         return;
126                 }
127
128                 $data = ['uri-id' => $uriid];
129                 $data['type'] = Post\Media::UNKNOWN;
130                 $data['url'] = $attachment['url'];
131                 $data['mimetype'] = $attachment['mediaType'] ?? null;
132                 $data['height'] = $attachment['height'] ?? null;
133                 $data['width'] = $attachment['width'] ?? null;
134                 $data['size'] = $attachment['size'] ?? null;
135                 $data['preview'] = $attachment['image'] ?? null;
136                 $data['description'] = $attachment['name'] ?? null;
137
138                 Post\Media::insert($data);
139         }
140
141         /**
142          * Stire attachment data
143          *
144          * @param array   $activity
145          * @param array   $item
146          */
147         private static function storeAttachments(array $activity, array $item)
148         {
149                 if (empty($activity['attachments'])) {
150                         return;
151                 }
152
153                 foreach ($activity['attachments'] as $attach) {
154                         self::storeAttachmentAsMedia($item['uri-id'], $attach);
155                 }
156         }
157
158         /**
159          * Store attachment data
160          *
161          * @param array   $activity
162          * @param array   $item
163          */
164         private static function storeQuestion(array $activity, array $item)
165         {
166                 if (empty($activity['question'])) {
167                         return;
168                 }
169                 $question = ['multiple' => $activity['question']['multiple']];
170
171                 if (!empty($activity['question']['voters'])) {
172                         $question['voters'] = $activity['question']['voters'];
173                 }
174
175                 if (!empty($activity['question']['end-time'])) {
176                         $question['end-time'] = DateTimeFormat::utc($activity['question']['end-time']);
177                 }
178
179                 Post\Question::update($item['uri-id'], $question);
180
181                 foreach ($activity['question']['options'] as $key => $option) {
182                         $option = ['name' => $option['name'], 'replies' => $option['replies']];
183                         Post\QuestionOption::update($item['uri-id'], $key, $option);
184                 }
185
186                 Logger::debug('Storing incoming question', ['type' => $activity['type'], 'uri-id' => $item['uri-id'], 'question' => $activity['question']]);
187         }
188
189         /**
190          * Updates a message
191          *
192          * @param array $activity Activity array
193          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
194          */
195         public static function updateItem(array $activity)
196         {
197                 $item = Post::selectFirst(['uri', 'uri-id', 'thr-parent', 'gravity', 'post-type'], ['uri' => $activity['id']]);
198                 if (!DBA::isResult($item)) {
199                         Logger::warning('No existing item, item will be created', ['uri' => $activity['id']]);
200                         $item = self::createItem($activity);
201                         if (empty($item)) {
202                                 return;
203                         }
204
205                         self::postItem($activity, $item);
206                         return;
207                 }
208
209                 $item['changed'] = DateTimeFormat::utcNow();
210                 $item['edited'] = DateTimeFormat::utc($activity['updated']);
211
212                 $item = self::processContent($activity, $item);
213
214                 self::storeAttachments($activity, $item);
215                 self::storeQuestion($activity, $item);
216
217                 if (empty($item)) {
218                         return;
219                 }
220
221                 Post\History::add($item['uri-id'], $item);
222                 Item::update($item, ['uri' => $activity['id']]);
223
224                 if ($activity['object_type'] == 'as:Event') {
225                         $posts = Post::select(['event-id', 'uid'], ["`uri` = ? AND `event-id` > ?", $activity['id'], 0]);
226                         while ($post = DBA::fetch($posts)) {
227                                 self::updateEvent($post['event-id'], $activity);
228                         }
229                 }
230         }
231
232         /**
233          * Update an existing event
234          *
235          * @param int $event_id
236          * @param array $activity
237          */
238         private static function updateEvent(int $event_id, array $activity)
239         {
240                 $event = DBA::selectFirst('event', [], ['id' => $event_id]);
241
242                 $event['edited']   = DateTimeFormat::utc($activity['updated']);
243                 $event['summary']  = HTML::toBBCode($activity['name']);
244                 $event['desc']     = HTML::toBBCode($activity['content']);
245                 if (!empty($activity['start-time'])) {
246                         $event['start']  = DateTimeFormat::utc($activity['start-time']);
247                 }
248                 if (!empty($activity['end-time'])) {
249                         $event['finish'] = DateTimeFormat::utc($activity['end-time']);
250                 }
251                 $event['nofinish'] = empty($event['finish']);
252                 $event['location'] = $activity['location'];
253
254                 Logger::info('Updating event', ['uri' => $activity['id'], 'id' => $event_id]);
255                 Event::store($event);
256         }
257
258         /**
259          * Prepares data for a message
260          *
261          * @param array $activity Activity array
262          * @return array Internal item
263          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
264          * @throws \ImagickException
265          */
266         public static function createItem(array $activity): array
267         {
268                 $item = [];
269                 $item['verb'] = Activity::POST;
270                 $item['thr-parent'] = $activity['reply-to-id'];
271
272                 if ($activity['reply-to-id'] == $activity['id']) {
273                         $item['gravity'] = GRAVITY_PARENT;
274                         $item['object-type'] = Activity\ObjectType::NOTE;
275                 } else {
276                         $item['gravity'] = GRAVITY_COMMENT;
277                         $item['object-type'] = Activity\ObjectType::COMMENT;
278                 }
279
280                 if (empty($activity['directmessage']) && ($activity['id'] != $activity['reply-to-id']) && !Post::exists(['uri' => $activity['reply-to-id']])) {
281                         Logger::notice('Parent not found. Try to refetch it.', ['parent' => $activity['reply-to-id']]);
282                         self::fetchMissingActivity($activity['reply-to-id'], $activity, '', Receiver::COMPLETION_AUTO);
283                 }
284
285                 $item['diaspora_signed_text'] = $activity['diaspora:comment'] ?? '';
286
287                 /// @todo What to do with $activity['context']?
288                 if (empty($activity['directmessage']) && ($item['gravity'] != GRAVITY_PARENT) && !Post::exists(['uri' => $item['thr-parent']])) {
289                         Logger::info('Parent not found, message will be discarded.', ['thr-parent' => $item['thr-parent']]);
290                         return [];
291                 }
292
293                 $item['network'] = Protocol::ACTIVITYPUB;
294                 $item['author-link'] = $activity['author'];
295                 $item['author-id'] = Contact::getIdForURL($activity['author']);
296                 $item['owner-link'] = $activity['actor'];
297                 $item['owner-id'] = Contact::getIdForURL($activity['actor']);
298
299                 if (in_array(0, $activity['receiver']) && !empty($activity['unlisted'])) {
300                         $item['private'] = Item::UNLISTED;
301                 } elseif (in_array(0, $activity['receiver'])) {
302                         $item['private'] = Item::PUBLIC;
303                 } else {
304                         $item['private'] = Item::PRIVATE;
305                 }
306
307                 if (!empty($activity['raw'])) {
308                         $item['source'] = $activity['raw'];
309                         $item['protocol'] = Conversation::PARCEL_ACTIVITYPUB;
310                         $item['conversation-href'] = $activity['context'] ?? '';
311                         $item['conversation-uri'] = $activity['conversation'] ?? '';
312
313                         if (isset($activity['push'])) {
314                                 $item['direction'] = $activity['push'] ? Conversation::PUSH : Conversation::PULL;
315                         }
316                 }
317
318                 if (!empty($activity['from-relay'])) {
319                         $item['direction'] = Conversation::RELAY;
320                 }
321
322                 if ($activity['object_type'] == 'as:Article') {
323                         $item['post-type'] = Item::PT_ARTICLE;
324                 } elseif ($activity['object_type'] == 'as:Audio') {
325                         $item['post-type'] = Item::PT_AUDIO;
326                 } elseif ($activity['object_type'] == 'as:Document') {
327                         $item['post-type'] = Item::PT_DOCUMENT;
328                 } elseif ($activity['object_type'] == 'as:Event') {
329                         $item['post-type'] = Item::PT_EVENT;
330                 } elseif ($activity['object_type'] == 'as:Image') {
331                         $item['post-type'] = Item::PT_IMAGE;
332                 } elseif ($activity['object_type'] == 'as:Page') {
333                         $item['post-type'] = Item::PT_PAGE;
334                 } elseif ($activity['object_type'] == 'as:Question') {
335                         $item['post-type'] = Item::PT_POLL;
336                 } elseif ($activity['object_type'] == 'as:Video') {
337                         $item['post-type'] = Item::PT_VIDEO;
338                 } else {
339                         $item['post-type'] = Item::PT_NOTE;
340                 }
341
342                 $item['isForum'] = false;
343
344                 if (!empty($activity['thread-completion'])) {
345                         if ($activity['thread-completion'] != $item['owner-id']) {
346                                 $actor = Contact::getById($activity['thread-completion'], ['url']);
347                                 $item['causer-link'] = $actor['url'];
348                                 $item['causer-id'] = $activity['thread-completion'];
349                                 Logger::info('Use inherited actor as causer.', ['id' => $item['owner-id'], 'activity' => $activity['thread-completion'], 'owner' => $item['owner-link'], 'actor' => $actor['url']]);
350                         } else {
351                                 // Store the original actor in the "causer" fields to enable the check for ignored or blocked contacts
352                                 $item['causer-link'] = $item['owner-link'];
353                                 $item['causer-id']   = $item['owner-id'];
354                                 Logger::info('Use actor as causer.', ['id' => $item['owner-id'], 'actor' => $item['owner-link']]);
355                         }
356
357                         $item['owner-link'] = $item['author-link'];
358                         $item['owner-id'] = $item['author-id'];
359                 } else {
360                         $actor = APContact::getByURL($item['owner-link'], false);
361                         $item['isForum'] = ($actor['type'] == 'Group');
362                 }
363
364                 $item['uri'] = $activity['id'];
365
366                 if (empty($activity['published']) || empty($activity['updated'])) {
367                         DI::logger()->notice('published or updated keys are empty for activity', ['activity' => $activity, 'callstack' => System::callstack(10)]);
368                 }
369
370                 $item['created'] = DateTimeFormat::utc($activity['published'] ?? 'now');
371                 $item['edited'] = DateTimeFormat::utc($activity['updated'] ?? 'now');
372                 $guid = $activity['sc:identifier'] ?: self::getGUIDByURL($item['uri']);
373                 $item['guid'] = $activity['diaspora:guid'] ?: $guid;
374
375                 $item['uri-id'] = ItemURI::insert(['uri' => $item['uri'], 'guid' => $item['guid']]);
376                 if (empty($item['uri-id'])) {
377                         Logger::warning('Unable to get a uri-id for an item uri', ['uri' => $item['uri'], 'guid' => $item['guid']]);
378                         return [];
379                 }
380
381                 $item = self::processContent($activity, $item);
382                 if (empty($item)) {
383                         Logger::info('Message was not processed');
384                         return [];
385                 }
386
387                 $item['plink'] = $activity['alternate-url'] ?? $item['uri'];
388
389                 self::storeAttachments($activity, $item);
390                 self::storeQuestion($activity, $item);
391
392                 // We received the post via AP, so we set the protocol of the server to AP
393                 $contact = Contact::getById($item['author-id'], ['gsid']);
394                 if (!empty($contact['gsid'])) {
395                         GServer::setProtocol($contact['gsid'], Post\DeliveryData::ACTIVITYPUB);
396                 }
397
398                 if ($item['author-id'] != $item['owner-id']) {
399                         $contact = Contact::getById($item['owner-id'], ['gsid']);
400                         if (!empty($contact['gsid'])) {
401                                 GServer::setProtocol($contact['gsid'], Post\DeliveryData::ACTIVITYPUB);
402                         }
403                 }
404
405                 return $item;
406         }
407
408         /**
409          * Delete items
410          *
411          * @param array $activity
412          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
413          * @throws \ImagickException
414          */
415         public static function deleteItem(array $activity)
416         {
417                 $owner = Contact::getIdForURL($activity['actor']);
418
419                 Logger::info('Deleting item', ['object' => $activity['object_id'], 'owner'  => $owner]);
420                 Item::markForDeletion(['uri' => $activity['object_id'], 'owner-id' => $owner]);
421         }
422
423         /**
424          * Prepare the item array for an activity
425          *
426          * @param array $activity Activity array
427          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
428          * @throws \ImagickException
429          */
430         public static function addTag(array $activity)
431         {
432                 if (empty($activity['object_content']) || empty($activity['object_id'])) {
433                         return;
434                 }
435
436                 foreach ($activity['receiver'] as $receiver) {
437                         $item = Post::selectFirst(['id', 'uri-id', 'origin', 'author-link'], ['uri' => $activity['target_id'], 'uid' => $receiver]);
438                         if (!DBA::isResult($item)) {
439                                 // We don't fetch missing content for this purpose
440                                 continue;
441                         }
442
443                         if (($item['author-link'] != $activity['actor']) && !$item['origin']) {
444                                 Logger::info('Not origin, not from the author, skipping update', ['id' => $item['id'], 'author' => $item['author-link'], 'actor' => $activity['actor']]);
445                                 continue;
446                         }
447
448                         Tag::store($item['uri-id'], Tag::HASHTAG, $activity['object_content'], $activity['object_id']);
449                         Logger::info('Tagged item', ['id' => $item['id'], 'tag' => $activity['object_content'], 'uri' => $activity['target_id'], 'actor' => $activity['actor']]);
450                 }
451         }
452
453         /**
454          * Prepare the item array for an activity
455          *
456          * @param array  $activity Activity array
457          * @param string $verb     Activity verb
458          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
459          * @throws \ImagickException
460          */
461         public static function createActivity(array $activity, string $verb)
462         {
463                 $item = self::createItem($activity);
464                 if (empty($item)) {
465                         return;
466                 }
467
468                 $item['verb'] = $verb;
469                 $item['thr-parent'] = $activity['object_id'];
470                 $item['gravity'] = GRAVITY_ACTIVITY;
471                 unset($item['post-type']);
472                 $item['object-type'] = Activity\ObjectType::NOTE;
473
474                 if (!empty($activity['content'])) {
475                         $item['body'] = HTML::toBBCode($activity['content']);
476                 }
477
478                 $item['diaspora_signed_text'] = $activity['diaspora:like'] ?? '';
479
480                 self::postItem($activity, $item);
481         }
482
483         /**
484          * Fetch the Uri-Id of a post for the "featured" collection
485          *
486          * @param array $activity
487          * @return null|int
488          */
489         private static function getUriIdForFeaturedCollection(array $activity)
490         {
491                 $actor = APContact::getByURL($activity['actor']);
492                 if (empty($actor)) {
493                         return null;
494                 }
495
496                 // Refetch the account when the "featured" collection is missing.
497                 // This can be removed in a future version (end of 2022 should be good).
498                 if (empty($actor['featured'])) {
499                         $actor = APContact::getByURL($activity['actor'], true);
500                         if (empty($actor)) {
501                                 return null;
502                         }
503                 }
504
505                 if ($activity['target_id'] != $actor['featured']) {
506                         return null;
507                 }
508
509                 $id = Contact::getIdForURL($activity['actor']);
510                 if (empty($id)) {
511                         return null;
512                 }
513
514                 $parent = Post::selectFirst(['uri-id'], ['uri' => $activity['object_id'], 'author-id' => $id]);
515                 if (!empty($parent['uri-id'])) {
516                         return $parent['uri-id'];
517                 }
518
519                 return null;
520         }
521
522         /**
523          * Add a post to the "Featured" collection
524          *
525          * @param array $activity
526          */
527         public static function addToFeaturedCollection(array $activity)
528         {
529                 $uriid = self::getUriIdForFeaturedCollection($activity);
530                 if (empty($uriid)) {
531                         return;
532                 }
533
534                 Logger::debug('Add post to featured collection', ['uri-id' => $uriid]);
535
536                 Post\Collection::add($uriid, Post\Collection::FEATURED);
537         }
538
539         /**
540          * Remove a post to the "Featured" collection
541          *
542          * @param array $activity
543          */
544         public static function removeFromFeaturedCollection(array $activity)
545         {
546                 $uriid = self::getUriIdForFeaturedCollection($activity);
547                 if (empty($uriid)) {
548                         return;
549                 }
550
551                 Logger::debug('Remove post from featured collection', ['uri-id' => $uriid]);
552
553                 Post\Collection::remove($uriid, Post\Collection::FEATURED);
554         }
555
556         /**
557          * Create an event
558          *
559          * @param array $activity Activity array
560          * @param array $item
561          *
562          * @return int event id
563          * @throws \Exception
564          */
565         public static function createEvent(array $activity, array $item): int
566         {
567                 $event['summary']   = HTML::toBBCode($activity['name'] ?: $activity['summary']);
568                 $event['desc']      = HTML::toBBCode($activity['content']);
569                 if (!empty($activity['start-time'])) {
570                         $event['start']  = DateTimeFormat::utc($activity['start-time']);
571                 }
572                 if (!empty($activity['end-time'])) {
573                         $event['finish'] = DateTimeFormat::utc($activity['end-time']);
574                 }
575                 $event['nofinish']  = empty($event['finish']);
576                 $event['location']  = $activity['location'];
577                 $event['cid']       = $item['contact-id'];
578                 $event['uid']       = $item['uid'];
579                 $event['uri']       = $item['uri'];
580                 $event['edited']    = $item['edited'];
581                 $event['private']   = $item['private'];
582                 $event['guid']      = $item['guid'];
583                 $event['plink']     = $item['plink'];
584                 $event['network']   = $item['network'];
585                 $event['protocol']  = $item['protocol'];
586                 $event['direction'] = $item['direction'];
587                 $event['source']    = $item['source'];
588
589                 $ev = DBA::selectFirst('event', ['id'], ['uri' => $item['uri'], 'uid' => $item['uid']]);
590                 if (DBA::isResult($ev)) {
591                         $event['id'] = $ev['id'];
592                 }
593
594                 $event_id = Event::store($event);
595
596                 Logger::info('Event was stored', ['id' => $event_id]);
597
598                 return $event_id;
599         }
600
601         /**
602          * Process the content
603          *
604          * @param array $activity Activity array
605          * @param array $item
606          * @return array|bool Returns the item array or false if there was an unexpected occurrence
607          * @throws \Exception
608          */
609         private static function processContent(array $activity, array $item)
610         {
611                 if (!empty($activity['mediatype']) && ($activity['mediatype'] == 'text/markdown')) {
612                         $item['title'] = strip_tags($activity['name']);
613                         $content = Markdown::toBBCode($activity['content']);
614                 } elseif (!empty($activity['mediatype']) && ($activity['mediatype'] == 'text/bbcode')) {
615                         $item['title'] = $activity['name'];
616                         $content = $activity['content'];
617                 } else {
618                         // By default assume "text/html"
619                         $item['title'] = HTML::toBBCode($activity['name'] ?? '');
620                         $content = HTML::toBBCode($activity['content'] ?? '');
621                 }
622
623                 $item['title'] = trim(BBCode::toPlaintext($item['title']));
624
625                 if (!empty($activity['languages'])) {
626                         $item['language'] = self::processLanguages($activity['languages']);
627                 }
628
629                 if (!empty($activity['emojis'])) {
630                         $content = self::replaceEmojis($item['uri-id'], $content, $activity['emojis']);
631                 }
632
633                 $content = self::addMentionLinks($content, $activity['tags']);
634
635                 if (!empty($activity['source'])) {
636                         $item['body'] = $activity['source'];
637                         $item['raw-body'] = $content;
638                         $item['body'] = Item::improveSharedDataInBody($item);
639                 } else {
640                         if (empty($activity['directmessage']) && ($item['thr-parent'] != $item['uri']) && ($item['gravity'] == GRAVITY_COMMENT)) {
641                                 $item_private = !in_array(0, $activity['item_receiver']);
642                                 $parent = Post::selectFirst(['id', 'uri-id', 'private', 'author-link', 'alias'], ['uri' => $item['thr-parent']]);
643                                 if (!DBA::isResult($parent)) {
644                                         Logger::warning('Unknown parent item.', ['uri' => $item['thr-parent']]);
645                                         return false;
646                                 }
647                                 if ($item_private && ($parent['private'] != Item::PRIVATE)) {
648                                         Logger::warning('Item is private but the parent is not. Dropping.', ['item-uri' => $item['uri'], 'thr-parent' => $item['thr-parent']]);
649                                         return false;
650                                 }
651
652                                 $content = self::removeImplicitMentionsFromBody($content, $parent);
653                         }
654                         $item['content-warning'] = HTML::toBBCode($activity['summary'] ?? '');
655                         $item['raw-body'] = $item['body'] = $content;
656                 }
657
658                 self::storeFromBody($item);
659                 self::storeTags($item['uri-id'], $activity['tags']);
660
661                 self::storeReceivers($item['uri-id'], $activity['receiver_urls'] ?? []);
662
663                 $item['location'] = $activity['location'];
664
665                 if (!empty($activity['latitude']) && !empty($activity['longitude'])) {
666                         $item['coord'] = $activity['latitude'] . ' ' . $activity['longitude'];
667                 }
668
669                 $item['app'] = $activity['generator'];
670
671                 return $item;
672         }
673
674         /**
675          * Store hashtags and mentions
676          *
677          * @param array $item
678          */
679         private static function storeFromBody(array $item)
680         {
681                 // Make sure to delete all existing tags (can happen when called via the update functionality)
682                 DBA::delete('post-tag', ['uri-id' => $item['uri-id']]);
683
684                 Tag::storeFromBody($item['uri-id'], $item['body'], '@!');
685         }
686
687         /**
688          * Generate a GUID out of an URL of an ActivityPub post.
689          *
690          * @param string $url message URL
691          * @return string with GUID
692          */
693         private static function getGUIDByURL(string $url): string
694         {
695                 $parsed = parse_url($url);
696
697                 $host_hash = hash('crc32', $parsed['host']);
698
699                 unset($parsed["scheme"]);
700                 unset($parsed["host"]);
701
702                 $path = implode("/", $parsed);
703
704                 return $host_hash . '-'. hash('fnv164', $path) . '-'. hash('joaat', $path);
705         }
706
707         /**
708          * Checks if an incoming message is wanted
709          *
710          * @param array $activity
711          * @param array $item
712          * @return boolean Is the message wanted?
713          */
714         private static function isSolicitedMessage(array $activity, array $item): bool
715         {
716                 // The checks are split to improve the support when searching why a message was accepted.
717                 if (count($activity['receiver']) != 1) {
718                         // The message has more than one receiver, so it is wanted.
719                         Logger::debug('Message has got several receivers - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
720                         return true;
721                 }
722
723                 if ($item['private'] == Item::PRIVATE) {
724                         // We only look at public posts here. Private posts are expected to be intentionally posted to the single receiver.
725                         Logger::debug('Message is private - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
726                         return true;
727                 }
728
729                 if (!empty($activity['from-relay'])) {
730                         // We check relay posts at another place. When it arrived here, the message is already checked.
731                         Logger::debug('Message is a relay post that is already checked - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
732                         return true;
733                 }
734
735                 if (in_array($activity['completion-mode'] ?? Receiver::COMPLETION_NONE, [Receiver::COMPLETION_MANUAL, Receiver::COMPLETION_ANNOUCE])) {
736                         // Manual completions and completions caused by reshares are allowed without any further checks.
737                         Logger::debug('Message is in completion mode - accepted', ['mode' => $activity['completion-mode'], 'uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
738                         return true;
739                 }
740
741                 if ($item['gravity'] != GRAVITY_PARENT) {
742                         // We cannot reliably check at this point if a comment or activity belongs to an accepted post or needs to be fetched
743                         // This can possibly be improved in the future.
744                         Logger::debug('Message is no parent - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
745                         return true;
746                 }
747
748                 $tags = array_column(Tag::getByURIId($item['uri-id'], [Tag::HASHTAG]), 'name');
749                 if (Relay::isSolicitedPost($tags, $item['body'], $item['author-id'], $item['uri'], Protocol::ACTIVITYPUB)) {
750                         Logger::debug('Post is accepted because of the relay settings', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
751                         return true;
752                 } else {
753                         return false;
754                 }
755         }
756
757         /**
758          * Creates an item post
759          *
760          * @param array $activity Activity data
761          * @param array $item     item array
762          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
763          * @throws \ImagickException
764          */
765         public static function postItem(array $activity, array $item)
766         {
767                 if (empty($item)) {
768                         return;
769                 }
770
771                 $stored = false;
772                 ksort($activity['receiver']);
773
774                 if (!self::isSolicitedMessage($activity, $item)) {
775                         DBA::delete('item-uri', ['id' => $item['uri-id']]);
776                         return;
777                 }
778
779                 foreach ($activity['receiver'] as $receiver) {
780                         if ($receiver == -1) {
781                                 continue;
782                         }
783
784                         $item['uid'] = $receiver;
785
786                         $type = $activity['reception_type'][$receiver] ?? Receiver::TARGET_UNKNOWN;
787                         switch($type) {
788                                 case Receiver::TARGET_TO:
789                                         $item['post-reason'] = Item::PR_TO;
790                                         break;
791                                 case Receiver::TARGET_CC:
792                                         $item['post-reason'] = Item::PR_CC;
793                                         break;
794                                 case Receiver::TARGET_BTO:
795                                         $item['post-reason'] = Item::PR_BTO;
796                                         break;
797                                 case Receiver::TARGET_BCC:
798                                         $item['post-reason'] = Item::PR_BCC;
799                                         break;
800                                 case Receiver::TARGET_FOLLOWER:
801                                         $item['post-reason'] = Item::PR_FOLLOWER;
802                                         break;
803                                 case Receiver::TARGET_ANSWER:
804                                         $item['post-reason'] = Item::PR_COMMENT;
805                                         break;
806                                 case Receiver::TARGET_GLOBAL:
807                                         $item['post-reason'] = Item::PR_GLOBAL;
808                                         break;
809                                 default:
810                                         $item['post-reason'] = Item::PR_NONE;
811                         }
812
813                         if (!empty($activity['from-relay'])) {
814                                 $item['post-reason'] = Item::PR_RELAY;
815                         } elseif (!empty($activity['thread-completion'])) {
816                                 $item['post-reason'] = Item::PR_FETCHED;
817                         }
818
819                         if ($item['isForum'] ?? false) {
820                                 $item['contact-id'] = Contact::getIdForURL($activity['actor'], $receiver);
821                         } else {
822                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver);
823                         }
824
825                         if (($receiver != 0) && empty($item['contact-id'])) {
826                                 $item['contact-id'] = Contact::getIdForURL($activity['author']);
827                         }
828
829                         if (!empty($activity['directmessage'])) {
830                                 self::postMail($activity, $item);
831                                 continue;
832                         }
833
834                         if (!($item['isForum'] ?? false) && ($receiver != 0) && ($item['gravity'] == GRAVITY_PARENT) && !Contact::isSharingByURL($activity['author'], $receiver)) {
835                                 if ($item['post-reason'] == Item::PR_BCC) {
836                                         Logger::info('Top level post via BCC from a non sharer, ignoring', ['uid' => $receiver, 'contact' => $item['contact-id']]);
837                                         continue;
838                                 }
839
840                                 if (
841                                         !empty($activity['thread-children-type'])
842                                         && in_array($activity['thread-children-type'], Receiver::ACTIVITY_TYPES)
843                                         && DI::pConfig()->get($receiver, 'system', 'accept_only_sharer') != Item::COMPLETION_LIKE
844                                 ) {
845                                         Logger::info('Top level post from thread completion from a non sharer had been initiated via an activity, ignoring',
846                                                 ['type' => $activity['thread-children-type'], 'user' => $item['uid'], 'causer' => $item['causer-link'], 'author' => $activity['author'], 'url' => $item['uri']]);
847                                         continue;
848                                 }
849                         }
850
851                         $is_forum = false;
852
853                         if ($receiver != 0) {
854                                 $user = User::getById($receiver, ['account-type']);
855                                 if (!empty($user['account-type'])) {
856                                         $is_forum = ($user['account-type'] == User::ACCOUNT_TYPE_COMMUNITY);
857                                 }
858                         }
859
860                         if (!$is_forum && DI::pConfig()->get($receiver, 'system', 'accept_only_sharer') == Item::COMPLETION_NONE && ($receiver != 0) && ($item['gravity'] == GRAVITY_PARENT)) {
861                                 $skip = !Contact::isSharingByURL($activity['author'], $receiver);
862
863                                 if ($skip && (($activity['type'] == 'as:Announce') || ($item['isForum'] ?? false))) {
864                                         $skip = !Contact::isSharingByURL($activity['actor'], $receiver);
865                                 }
866
867                                 if ($skip) {
868                                         Logger::info('Skipping post', ['uid' => $receiver, 'url' => $item['uri']]);
869                                         continue;
870                                 }
871
872                                 Logger::info('Accepting post', ['uid' => $receiver, 'url' => $item['uri']]);
873                         }
874
875                         if (($item['gravity'] != GRAVITY_ACTIVITY) && ($activity['object_type'] == 'as:Event')) {
876                                 $event_id = self::createEvent($activity, $item);
877
878                                 $item = Event::getItemArrayForImportedId($event_id, $item);
879                         }
880
881                         $item_id = Item::insert($item);
882                         if ($item_id) {
883                                 Logger::info('Item insertion successful', ['user' => $item['uid'], 'item_id' => $item_id]);
884                         } else {
885                                 Logger::notice('Item insertion aborted', ['user' => $item['uid']]);
886                         }
887
888                         if ($item['uid'] == 0) {
889                                 $stored = $item_id;
890                         }
891                 }
892
893                 // Store send a follow request for every reshare - but only when the item had been stored
894                 if ($stored && ($item['private'] != Item::PRIVATE) && ($item['gravity'] == GRAVITY_PARENT) && ($item['author-link'] != $item['owner-link'])) {
895                         $author = APContact::getByURL($item['owner-link'], false);
896                         // We send automatic follow requests for reshared messages. (We don't need though for forum posts)
897                         if ($author['type'] != 'Group') {
898                                 Logger::info('Send follow request', ['uri' => $item['uri'], 'stored' => $stored, 'to' => $item['author-link']]);
899                                 ActivityPub\Transmitter::sendFollowObject($item['uri'], $item['author-link']);
900                         }
901                 }
902         }
903
904         /**
905          * Store tags and mentions into the tag table
906          *
907          * @param integer $uriid
908          * @param array $tags
909          */
910         private static function storeTags(int $uriid, array $tags = null)
911         {
912                 foreach ($tags as $tag) {
913                         if (empty($tag['name']) || empty($tag['type']) || !in_array($tag['type'], ['Mention', 'Hashtag'])) {
914                                 continue;
915                         }
916
917                         $hash = substr($tag['name'], 0, 1);
918
919                         if ($tag['type'] == 'Mention') {
920                                 if (in_array($hash, [Tag::TAG_CHARACTER[Tag::MENTION],
921                                         Tag::TAG_CHARACTER[Tag::EXCLUSIVE_MENTION],
922                                         Tag::TAG_CHARACTER[Tag::IMPLICIT_MENTION]])) {
923                                         $tag['name'] = substr($tag['name'], 1);
924                                 }
925                                 $type = Tag::IMPLICIT_MENTION;
926
927                                 if (!empty($tag['href'])) {
928                                         $apcontact = APContact::getByURL($tag['href']);
929                                         if (!empty($apcontact['name']) || !empty($apcontact['nick'])) {
930                                                 $tag['name'] = $apcontact['name'] ?: $apcontact['nick'];
931                                         }
932                                 }
933                         } elseif ($tag['type'] == 'Hashtag') {
934                                 if ($hash == Tag::TAG_CHARACTER[Tag::HASHTAG]) {
935                                         $tag['name'] = substr($tag['name'], 1);
936                                 }
937                                 $type = Tag::HASHTAG;
938                         }
939
940                         if (empty($tag['name'])) {
941                                 continue;
942                         }
943
944                         Tag::store($uriid, $type, $tag['name'], $tag['href']);
945                 }
946         }
947
948         public static function storeReceivers(int $uriid, array $receivers)
949         {
950                 foreach (['as:to' => Tag::TO, 'as:cc' => Tag::CC, 'as:bto' => Tag::BTO, 'as:bcc' => Tag::BCC] as $element => $type) {
951                         if (!empty($receivers[$element])) {
952                                 foreach ($receivers[$element] as $receiver) {
953                                         if ($receiver == ActivityPub::PUBLIC_COLLECTION) {
954                                                 $name = Receiver::PUBLIC_COLLECTION;
955                                         } else {
956                                                 $name = trim(parse_url($receiver, PHP_URL_PATH), '/');
957                                         }
958
959                                         $target = Tag::getTargetType($receiver);
960                                         Logger::debug('Got target type', ['type' => $target, 'url' => $receiver]);
961                                         Tag::store($uriid, $type, $name, $receiver, $target);
962                                 }
963                         }
964                 }
965         }
966
967         /**
968          * Creates an mail post
969          *
970          * @param array $activity Activity data
971          * @param array $item     item array
972          * @return int|bool New mail table row id or false on error
973          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
974          */
975         private static function postMail(array $activity, array $item)
976         {
977                 if (($item['gravity'] != GRAVITY_PARENT) && !DBA::exists('mail', ['uri' => $item['thr-parent'], 'uid' => $item['uid']])) {
978                         Logger::info('Parent not found, mail will be discarded.', ['uid' => $item['uid'], 'uri' => $item['thr-parent']]);
979                         return false;
980                 }
981
982                 Logger::info('Direct Message', $item);
983
984                 $msg = [];
985                 $msg['uid'] = $item['uid'];
986
987                 $msg['contact-id'] = $item['contact-id'];
988
989                 $contact = Contact::getById($item['contact-id'], ['name', 'url', 'photo']);
990                 $msg['from-name'] = $contact['name'];
991                 $msg['from-url'] = $contact['url'];
992                 $msg['from-photo'] = $contact['photo'];
993
994                 $msg['uri'] = $item['uri'];
995                 $msg['created'] = $item['created'];
996
997                 $parent = DBA::selectFirst('mail', ['parent-uri', 'title'], ['uri' => $item['thr-parent']]);
998                 if (DBA::isResult($parent)) {
999                         $msg['parent-uri'] = $parent['parent-uri'];
1000                         $msg['title'] = $parent['title'];
1001                 } else {
1002                         $msg['parent-uri'] = $item['thr-parent'];
1003
1004                         if (!empty($item['title'])) {
1005                                 $msg['title'] = $item['title'];
1006                         } elseif (!empty($item['content-warning'])) {
1007                                 $msg['title'] = $item['content-warning'];
1008                         } else {
1009                                 // Trying to generate a title out of the body
1010                                 $title = $item['body'];
1011
1012                                 while (preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $title, $matches)) {
1013                                         $title = $matches[3];
1014                                 }
1015
1016                                 $title = trim(BBCode::toPlaintext($title));
1017
1018                                 if (strlen($title) > 20) {
1019                                         $title = substr($title, 0, 20) . '...';
1020                                 }
1021
1022                                 $msg['title'] = $title;
1023                         }
1024                 }
1025                 $msg['body'] = $item['body'];
1026
1027                 return Mail::insert($msg);
1028         }
1029
1030         /**
1031          * Fetch featured posts from a contact with the given url
1032          *
1033          * @param string $url
1034          * @return void
1035          */
1036         public static function fetchFeaturedPosts(string $url)
1037         {
1038                 Logger::info('Fetch featured posts', ['contact' => $url]);
1039
1040                 $apcontact = APContact::getByURL($url);
1041                 if (empty($apcontact['featured'])) {
1042                         Logger::info('Contact does not have a featured collection', ['contact' => $url]);
1043                         return;
1044                 }
1045
1046                 $pcid = Contact::getIdForURL($url, 0, false);
1047                 if (empty($pcid)) {
1048                         Logger::info('Contact not found', ['contact' => $url]);
1049                         return;
1050                 }
1051
1052                 $posts = Post\Collection::selectToArrayForContact($pcid, Post\Collection::FEATURED);
1053                 if (!empty($posts)) {
1054                         $old_featured = array_column($posts, 'uri-id');
1055                 } else {
1056                         $old_featured = [];
1057                 }
1058
1059                 $featured = ActivityPub::fetchItems($apcontact['featured']);
1060                 if (empty($featured)) {
1061                         Logger::info('Contact does not have featured posts', ['contact' => $url]);
1062
1063                         foreach ($old_featured as $uri_id) {
1064                                 Post\Collection::remove($uri_id, Post\Collection::FEATURED);
1065                                 Logger::debug('Removed no longer featured post', ['uri-id' => $uri_id, 'contact' => $url]);
1066                         }
1067                         return;
1068                 }
1069
1070                 $new = 0;
1071                 $old = 0;
1072
1073                 foreach ($featured as $post) {
1074                         if (empty($post['id'])) {
1075                                 continue;
1076                         }
1077                         $id = Item::fetchByLink($post['id']);
1078                         if (!empty($id)) {
1079                                 $item = Post::selectFirst(['uri-id', 'featured'], ['id' => $id]);
1080                                 if (!empty($item['uri-id'])) {
1081                                         if (!$item['featured']) {
1082                                                 Post\Collection::add($item['uri-id'], Post\Collection::FEATURED);
1083                                                 Logger::debug('Added featured post', ['uri-id' => $item['uri-id'], 'contact' => $url]);
1084                                                 $new++;
1085                                         } else {
1086                                                 Logger::debug('Post already had been featured', ['uri-id' => $item['uri-id'], 'contact' => $url]);
1087                                                 $old++;
1088                                         }
1089
1090                                         $index = array_search($item['uri-id'], $old_featured);
1091                                         if (!($index === false)) {
1092                                                 unset($old_featured[$index]);
1093                                         }
1094                                 }
1095                         }
1096                 }
1097
1098                 foreach ($old_featured as $uri_id) {
1099                         Post\Collection::remove($uri_id, Post\Collection::FEATURED);
1100                         Logger::debug('Removed no longer featured post', ['uri-id' => $uri_id, 'contact' => $url]);
1101                 }
1102
1103                 Logger::info('Fetched featured posts', ['new' => $new, 'old' => $old, 'contact' => $url]);
1104         }
1105
1106         /**
1107          * Fetches missing posts
1108          *
1109          * @param string $url         message URL
1110          * @param array  $child       activity array with the child of this message
1111          * @param string $relay_actor Relay actor
1112          * @param int    $completion  Completion mode, see Receiver::COMPLETION_*
1113          * @return string fetched message URL
1114          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1115          */
1116         public static function fetchMissingActivity(string $url, array $child = [], string $relay_actor = '', int $completion = Receiver::COMPLETION_MANUAL): string
1117         {
1118                 if (!empty($child['receiver'])) {
1119                         $uid = ActivityPub\Receiver::getFirstUserFromReceivers($child['receiver']);
1120                 } else {
1121                         $uid = 0;
1122                 }
1123
1124                 $object = ActivityPub::fetchContent($url, $uid);
1125                 if (empty($object)) {
1126                         Logger::notice('Activity was not fetchable, aborting.', ['url' => $url]);
1127                         return '';
1128                 }
1129
1130                 if (empty($object['id'])) {
1131                         Logger::notice('Activity has got not id, aborting. ', ['url' => $url, 'object' => $object]);
1132                         return '';
1133                 }
1134
1135                 if (!empty($object['actor'])) {
1136                         $object_actor = $object['actor'];
1137                 } elseif (!empty($object['attributedTo'])) {
1138                         $object_actor = $object['attributedTo'];
1139                         if (is_array($object_actor)) {
1140                                 $compacted = JsonLD::compact($object);
1141                                 $object_actor = JsonLD::fetchElement($compacted, 'as:attributedTo', '@id');
1142                         }
1143                 } else {
1144                         // Shouldn't happen
1145                         $object_actor = '';
1146                 }
1147
1148                 $signer = [$object_actor];
1149
1150                 if (!empty($child['author'])) {
1151                         $actor = $child['author'];
1152                         $signer[] = $actor;
1153                 } else {
1154                         $actor = $object_actor;
1155                 }
1156
1157                 if (!empty($object['published'])) {
1158                         $published = $object['published'];
1159                 } elseif (!empty($child['published'])) {
1160                         $published = $child['published'];
1161                 } else {
1162                         $published = DateTimeFormat::utcNow();
1163                 }
1164
1165                 $activity = [];
1166                 $activity['@context'] = $object['@context'] ?? ActivityPub::CONTEXT;
1167                 unset($object['@context']);
1168                 $activity['id'] = $object['id'];
1169                 $activity['to'] = $object['to'] ?? [];
1170                 $activity['cc'] = $object['cc'] ?? [];
1171                 $activity['actor'] = $actor;
1172                 $activity['object'] = $object;
1173                 $activity['published'] = $published;
1174                 $activity['type'] = 'Create';
1175
1176                 $ldactivity = JsonLD::compact($activity);
1177
1178                 if (!empty($relay_actor)) {
1179                         $ldactivity['thread-completion'] = $ldactivity['from-relay'] = Contact::getIdForURL($relay_actor);
1180                         $ldactivity['completion-mode']   = Receiver::COMPLETION_RELAY;
1181                 } elseif (!empty($child['thread-completion'])) {
1182                         $ldactivity['thread-completion'] = $child['thread-completion'];
1183                         $ldactivity['completion-mode']   = $child['completion-mode'] ?? Receiver::COMPLETION_NONE;
1184                 } else {
1185                         $ldactivity['thread-completion'] = Contact::getIdForURL($actor);
1186                         $ldactivity['completion-mode']   = $completion;
1187                 }
1188
1189                 if (!empty($child['type'])) {
1190                         $ldactivity['thread-children-type'] = $child['type'];
1191                 }
1192
1193                 if (!empty($relay_actor) && !self::acceptIncomingMessage($ldactivity, $object['id'])) {
1194                         return '';
1195                 }
1196
1197                 ActivityPub\Receiver::processActivity($ldactivity, json_encode($activity), $uid, true, false, $signer);
1198
1199                 Logger::notice('Activity had been fetched and processed.', ['url' => $url, 'object' => $activity['id']]);
1200
1201                 return $activity['id'];
1202         }
1203
1204         /**
1205          * Test if incoming relay messages should be accepted
1206          *
1207          * @param array $activity activity array
1208          * @param string $id      object ID
1209          * @return boolean true if message is accepted
1210          */
1211         private static function acceptIncomingMessage(array $activity, string $id): bool
1212         {
1213                 if (empty($activity['as:object'])) {
1214                         Logger::info('No object field in activity - accepted', ['id' => $id]);
1215                         return true;
1216                 }
1217
1218                 $replyto = JsonLD::fetchElement($activity['as:object'], 'as:inReplyTo', '@id');
1219                 $uriid = ItemURI::getIdByURI($replyto ?? '');
1220                 if (Post::exists(['uri-id' => $uriid])) {
1221                         Logger::info('Post is a reply to an existing post - accepted', ['id' => $id, 'uri-id' => $uriid, 'replyto' => $replyto]);
1222                         return true;
1223                 }
1224
1225                 $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
1226                 $authorid = Contact::getIdForURL($attributed_to);
1227
1228                 $body = HTML::toBBCode(JsonLD::fetchElement($activity['as:object'], 'as:content', '@value') ?? '');
1229
1230                 $messageTags = [];
1231                 $tags = Receiver::processTags(JsonLD::fetchElementArray($activity['as:object'], 'as:tag') ?? []);
1232                 if (!empty($tags)) {
1233                         foreach ($tags as $tag) {
1234                                 if ($tag['type'] != 'Hashtag') {
1235                                         continue;
1236                                 }
1237                                 $messageTags[] = ltrim(mb_strtolower($tag['name']), '#');
1238                         }
1239                 }
1240
1241                 return Relay::isSolicitedPost($messageTags, $body, $authorid, $id, Protocol::ACTIVITYPUB);
1242         }
1243
1244         /**
1245          * perform a "follow" request
1246          *
1247          * @param array $activity
1248          * @return void
1249          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1250          * @throws \ImagickException
1251          */
1252         public static function followUser(array $activity)
1253         {
1254                 $uid = User::getIdForURL($activity['object_id']);
1255                 if (empty($uid)) {
1256                         return;
1257                 }
1258
1259                 $owner = User::getOwnerDataById($uid);
1260                 if (empty($owner)) {
1261                         return;
1262                 }
1263
1264                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1265                 if (!empty($cid)) {
1266                         self::switchContact($cid);
1267                         Contact::update(['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
1268                 }
1269
1270                 $item = [
1271                         'author-id' => Contact::getIdForURL($activity['actor']),
1272                         'author-link' => $activity['actor'],
1273                 ];
1274
1275                 // Ensure that the contact has got the right network type
1276                 self::switchContact($item['author-id']);
1277
1278                 $result = Contact::addRelationship($owner, [], $item, false, $activity['content'] ?? '');
1279                 if ($result === true) {
1280                         ActivityPub\Transmitter::sendContactAccept($item['author-link'], $activity['id'], $owner['uid']);
1281                 }
1282
1283                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1284                 if (empty($cid)) {
1285                         return;
1286                 }
1287
1288                 if ($result && DI::config()->get('system', 'transmit_pending_events') && ($owner['contact-type'] == Contact::TYPE_COMMUNITY)) {
1289                         self::transmitPendingEvents($cid, $owner['uid']);
1290                 }
1291
1292                 if (empty($contact)) {
1293                         Contact::update(['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
1294                 }
1295
1296                 Logger::notice('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
1297         }
1298
1299         /**
1300          * Transmit pending events to the new follower
1301          *
1302          * @param integer $cid Contact id
1303          * @param integer $uid User id
1304          * @return void
1305          */
1306         private static function transmitPendingEvents(int $cid, int $uid)
1307         {
1308                 $account = DBA::selectFirst('account-user-view', ['ap-inbox', 'ap-sharedinbox'], ['id' => $cid]);
1309                 $inbox = $account['ap-sharedinbox'] ?: $account['ap-inbox'];
1310
1311                 $events = DBA::select('event', ['id'], ["`uid` = ? AND `start` > ? AND `type` != ?", $uid, DateTimeFormat::utcNow(), 'birthday']);
1312                 while ($event = DBA::fetch($events)) {
1313                         $post = Post::selectFirst(['id', 'uri-id', 'created'], ['event-id' => $event['id']]);
1314                         if (empty($post)) {
1315                                 continue;
1316                         }
1317                         if (DI::config()->get('system', 'bulk_delivery')) {
1318                                 Post\Delivery::add($post['uri-id'], $uid, $inbox, $post['created'], Delivery::POST, [$cid]);
1319                                 Worker::add(PRIORITY_HIGH, 'APDelivery', '', 0, $inbox, 0);
1320                         } else {
1321                                 Worker::add(PRIORITY_HIGH, 'APDelivery', Delivery::POST, $post['id'], $inbox, $uid, [$cid], $post['uri-id']);
1322                         }
1323                 }
1324         }
1325
1326         /**
1327          * Update the given profile
1328          *
1329          * @param array $activity
1330          * @throws \Exception
1331          */
1332         public static function updatePerson(array $activity)
1333         {
1334                 if (empty($activity['object_id'])) {
1335                         return;
1336                 }
1337
1338                 Logger::info('Updating profile', ['object' => $activity['object_id']]);
1339                 Contact::updateFromProbeByURL($activity['object_id']);
1340         }
1341
1342         /**
1343          * Delete the given profile
1344          *
1345          * @param array $activity
1346          * @return void
1347          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1348          */
1349         public static function deletePerson(array $activity)
1350         {
1351                 if (empty($activity['object_id']) || empty($activity['actor'])) {
1352                         Logger::info('Empty object id or actor.');
1353                         return;
1354                 }
1355
1356                 if ($activity['object_id'] != $activity['actor']) {
1357                         Logger::info('Object id does not match actor.');
1358                         return;
1359                 }
1360
1361                 $contacts = DBA::select('contact', ['id'], ['nurl' => Strings::normaliseLink($activity['object_id'])]);
1362                 while ($contact = DBA::fetch($contacts)) {
1363                         Contact::remove($contact['id']);
1364                 }
1365                 DBA::close($contacts);
1366
1367                 Logger::info('Deleted contact', ['object' => $activity['object_id']]);
1368         }
1369
1370         /**
1371          * Blocks the user by the contact
1372          *
1373          * @param array $activity
1374          * @return void
1375          * @throws \Exception
1376          */
1377         public static function blockAccount(array $activity)
1378         {
1379                 $cid = Contact::getIdForURL($activity['actor']);
1380                 if (empty($cid)) {
1381                         return;
1382                 }
1383
1384                 $uid = User::getIdForURL($activity['object_id']);
1385                 if (empty($uid)) {
1386                         return;
1387                 }
1388
1389                 Contact\User::setIsBlocked($cid, $uid, true);
1390
1391                 Logger::info('Contact blocked user', ['contact' => $cid, 'user' => $uid]);
1392         }
1393
1394         /**
1395          * Unblocks the user by the contact
1396          *
1397          * @param array $activity
1398          * @return void
1399          * @throws \Exception
1400          */
1401         public static function unblockAccount(array $activity)
1402         {
1403                 $cid = Contact::getIdForURL($activity['actor']);
1404                 if (empty($cid)) {
1405                         return;
1406                 }
1407
1408                 $uid = User::getIdForURL($activity['object_object']);
1409                 if (empty($uid)) {
1410                         return;
1411                 }
1412
1413                 Contact\User::setIsBlocked($cid, $uid, false);
1414
1415                 Logger::info('Contact unblocked user', ['contact' => $cid, 'user' => $uid]);
1416         }
1417
1418         /**
1419          * Accept a follow request
1420          *
1421          * @param array $activity
1422          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1423          * @throws \ImagickException
1424          */
1425         public static function acceptFollowUser(array $activity)
1426         {
1427                 $uid = User::getIdForURL($activity['object_actor']);
1428                 if (empty($uid)) {
1429                         return;
1430                 }
1431
1432                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1433                 if (empty($cid)) {
1434                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1435                         return;
1436                 }
1437
1438                 self::switchContact($cid);
1439
1440                 $fields = ['pending' => false];
1441
1442                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
1443                 if ($contact['rel'] == Contact::FOLLOWER) {
1444                         $fields['rel'] = Contact::FRIEND;
1445                 }
1446
1447                 $condition = ['id' => $cid];
1448                 Contact::update($fields, $condition);
1449                 Logger::info('Accept contact request', ['contact' => $cid, 'user' => $uid]);
1450         }
1451
1452         /**
1453          * Reject a follow request
1454          *
1455          * @param array $activity
1456          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1457          * @throws \ImagickException
1458          */
1459         public static function rejectFollowUser(array $activity)
1460         {
1461                 $uid = User::getIdForURL($activity['object_actor']);
1462                 if (empty($uid)) {
1463                         return;
1464                 }
1465
1466                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1467                 if (empty($cid)) {
1468                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1469                         return;
1470                 }
1471
1472                 self::switchContact($cid);
1473
1474                 $contact = Contact::getById($cid, ['rel']);
1475                 if ($contact['rel'] == Contact::SHARING) {
1476                         Contact::remove($cid);
1477                         Logger::info('Rejected contact request - contact removed', ['contact' => $cid, 'user' => $uid]);
1478                 } elseif ($contact['rel'] == Contact::FRIEND) {
1479                         Contact::update(['rel' => Contact::FOLLOWER], ['id' => $cid]);
1480                 } else {
1481                         Logger::info('Rejected contact request', ['contact' => $cid, 'user' => $uid]);
1482                 }
1483         }
1484
1485         /**
1486          * Undo activity like "like" or "dislike"
1487          *
1488          * @param array $activity
1489          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1490          * @throws \ImagickException
1491          */
1492         public static function undoActivity(array $activity)
1493         {
1494                 if (empty($activity['object_id'])) {
1495                         return;
1496                 }
1497
1498                 if (empty($activity['object_actor'])) {
1499                         return;
1500                 }
1501
1502                 $author_id = Contact::getIdForURL($activity['object_actor']);
1503                 if (empty($author_id)) {
1504                         return;
1505                 }
1506
1507                 Item::markForDeletion(['uri' => $activity['object_id'], 'author-id' => $author_id, 'gravity' => GRAVITY_ACTIVITY]);
1508         }
1509
1510         /**
1511          * Activity to remove a follower
1512          *
1513          * @param array $activity
1514          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1515          * @throws \ImagickException
1516          */
1517         public static function undoFollowUser(array $activity)
1518         {
1519                 $uid = User::getIdForURL($activity['object_object']);
1520                 if (empty($uid)) {
1521                         return;
1522                 }
1523
1524                 $owner = User::getOwnerDataById($uid);
1525                 if (empty($owner)) {
1526                         return;
1527                 }
1528
1529                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1530                 if (empty($cid)) {
1531                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1532                         return;
1533                 }
1534
1535                 self::switchContact($cid);
1536
1537                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1538                 if (!DBA::isResult($contact)) {
1539                         return;
1540                 }
1541
1542                 Contact::removeFollower($contact);
1543                 Logger::info('Undo following request', ['contact' => $cid, 'user' => $uid]);
1544         }
1545
1546         /**
1547          * Switches a contact to AP if needed
1548          *
1549          * @param integer $cid Contact ID
1550          * @throws \Exception
1551          */
1552         private static function switchContact(int $cid)
1553         {
1554                 $contact = DBA::selectFirst('contact', ['network', 'url'], ['id' => $cid]);
1555                 if (!DBA::isResult($contact) || in_array($contact['network'], [Protocol::ACTIVITYPUB, Protocol::DFRN]) || Contact::isLocal($contact['url'])) {
1556                         return;
1557                 }
1558
1559                 Logger::info('Change existing contact', ['cid' => $cid, 'previous' => $contact['network']]);
1560                 Contact::updateFromProbe($cid);
1561         }
1562
1563         /**
1564          * Collects implicit mentions like:
1565          * - the author of the parent item
1566          * - all the mentioned conversants in the parent item
1567          *
1568          * @param array $parent Item array with at least ['id', 'author-link', 'alias']
1569          * @return array
1570          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1571          */
1572         private static function getImplicitMentionList(array $parent): array
1573         {
1574                 $parent_terms = Tag::getByURIId($parent['uri-id'], [Tag::MENTION, Tag::IMPLICIT_MENTION, Tag::EXCLUSIVE_MENTION]);
1575
1576                 $parent_author = Contact::getByURL($parent['author-link'], false, ['url', 'nurl', 'alias']);
1577
1578                 $implicit_mentions = [];
1579                 if (empty($parent_author['url'])) {
1580                         Logger::notice('Author public contact unknown.', ['author-link' => $parent['author-link'], 'parent-id' => $parent['id']]);
1581                 } else {
1582                         $implicit_mentions[] = $parent_author['url'];
1583                         $implicit_mentions[] = $parent_author['nurl'];
1584                         $implicit_mentions[] = $parent_author['alias'];
1585                 }
1586
1587                 if (!empty($parent['alias'])) {
1588                         $implicit_mentions[] = $parent['alias'];
1589                 }
1590
1591                 foreach ($parent_terms as $term) {
1592                         $contact = Contact::getByURL($term['url'], false, ['url', 'nurl', 'alias']);
1593                         if (!empty($contact['url'])) {
1594                                 $implicit_mentions[] = $contact['url'];
1595                                 $implicit_mentions[] = $contact['nurl'];
1596                                 $implicit_mentions[] = $contact['alias'];
1597                         }
1598                 }
1599
1600                 return $implicit_mentions;
1601         }
1602
1603         /**
1604          * Strips from the body prepended implicit mentions
1605          *
1606          * @param string $body
1607          * @param array $parent
1608          * @return string
1609          */
1610         private static function removeImplicitMentionsFromBody(string $body, array $parent): string
1611         {
1612                 if (DI::config()->get('system', 'disable_implicit_mentions')) {
1613                         return $body;
1614                 }
1615
1616                 $potential_mentions = self::getImplicitMentionList($parent);
1617
1618                 $kept_mentions = [];
1619
1620                 // Extract one prepended mention at a time from the body
1621                 while(preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $body, $matches)) {
1622                         if (!in_array($matches[2], $potential_mentions)) {
1623                                 $kept_mentions[] = $matches[1];
1624                         }
1625
1626                         $body = $matches[3];
1627                 }
1628
1629                 // Re-appending the kept mentions to the body after extraction
1630                 $kept_mentions[] = $body;
1631
1632                 return implode('', $kept_mentions);
1633         }
1634
1635         /**
1636          * Adds links to string mentions
1637          *
1638          * @param string $body
1639          * @param array  $tags
1640          * @return string
1641          */
1642         protected static function addMentionLinks(string $body, array $tags): string
1643         {
1644                 // This prevents links to be added again to Pleroma-style mention links
1645                 $body = self::normalizeMentionLinks($body);
1646
1647                 $body = BBCode::performWithEscapedTags($body, ['url'], function ($body) use ($tags) {
1648                         foreach ($tags as $tag) {
1649                                 if (empty($tag['name']) || empty($tag['type']) || empty($tag['href']) || !in_array($tag['type'], ['Mention', 'Hashtag'])) {
1650                                         continue;
1651                                 }
1652
1653                                 $hash = substr($tag['name'], 0, 1);
1654                                 $name = substr($tag['name'], 1);
1655                                 if (!in_array($hash, Tag::TAG_CHARACTER)) {
1656                                         $hash = '';
1657                                         $name = $tag['name'];
1658                                 }
1659
1660                                 $body = str_replace($tag['name'], $hash . '[url=' . $tag['href'] . ']' . $name . '[/url]', $body);
1661                         }
1662
1663                         return $body;
1664                 });
1665
1666                 return $body;
1667         }
1668 }