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Config for receiver / fix fatals
[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\Cache\Enum\Duration;
28 use Friendica\Core\Logger;
29 use Friendica\Core\Protocol;
30 use Friendica\Core\System;
31 use Friendica\Core\Worker;
32 use Friendica\Database\DBA;
33 use Friendica\DI;
34 use Friendica\Model\APContact;
35 use Friendica\Model\Contact;
36 use Friendica\Model\Conversation;
37 use Friendica\Model\Event;
38 use Friendica\Model\GServer;
39 use Friendica\Model\Item;
40 use Friendica\Model\ItemURI;
41 use Friendica\Model\Mail;
42 use Friendica\Model\Tag;
43 use Friendica\Model\User;
44 use Friendica\Model\Post;
45 use Friendica\Protocol\Activity;
46 use Friendica\Protocol\ActivityPub;
47 use Friendica\Protocol\Relay;
48 use Friendica\Util\DateTimeFormat;
49 use Friendica\Util\HTTPSignature;
50 use Friendica\Util\JsonLD;
51 use Friendica\Util\Network;
52 use Friendica\Util\Strings;
53 use Friendica\Worker\Delivery;
54
55 /**
56  * ActivityPub Processor Protocol class
57  */
58 class Processor
59 {
60         const CACHEKEY_FETCH_ACTIVITY = 'processor:fetchMissingActivity:';
61         /**
62          * Extracts the tag character (#, @, !) from mention links
63          *
64          * @param string $body
65          * @return string
66          */
67         protected static function normalizeMentionLinks(string $body): string
68         {
69                 return preg_replace('%\[url=([^\[\]]*)]([#@!])(.*?)\[/url]%ism', '$2[url=$1]$3[/url]', $body);
70         }
71
72         /**
73          * Convert the language array into a language JSON
74          *
75          * @param array $languages
76          * @return string language JSON
77          */
78         private static function processLanguages(array $languages): string
79         {
80                 $codes = array_keys($languages);
81                 $lang = [];
82                 foreach ($codes as $code) {
83                         $lang[$code] = 1;
84                 }
85
86                 if (empty($lang)) {
87                         return '';
88                 }
89
90                 return json_encode($lang);
91         }
92         /**
93          * Replaces emojis in the body
94          *
95          * @param int $uri_id
96          * @param string $body
97          * @param array $emojis
98          *
99          * @return string with replaced emojis
100          */
101         private static function replaceEmojis(int $uri_id, string $body, array $emojis): string
102         {
103                 $body = strtr($body,
104                         array_combine(
105                                 array_column($emojis, 'name'),
106                                 array_map(function ($emoji) {
107                                         return '[emoji=' . $emoji['href'] . ']' . $emoji['name'] . '[/emoji]';
108                                 }, $emojis)
109                         )
110                 );
111
112                 // We store the emoji here to be able to avoid storing it in the media
113                 foreach ($emojis as $emoji) {
114                         Post\Link::getByLink($uri_id, $emoji['href']);
115                 }
116                 return $body;
117         }
118
119         /**
120          * Store attached media files in the post-media table
121          *
122          * @param int $uriid
123          * @param array $attachment
124          * @return void
125          */
126         private static function storeAttachmentAsMedia(int $uriid, array $attachment)
127         {
128                 if (empty($attachment['url'])) {
129                         return;
130                 }
131
132                 $data = ['uri-id' => $uriid];
133                 $data['type'] = Post\Media::UNKNOWN;
134                 $data['url'] = $attachment['url'];
135                 $data['mimetype'] = $attachment['mediaType'] ?? null;
136                 $data['height'] = $attachment['height'] ?? null;
137                 $data['width'] = $attachment['width'] ?? null;
138                 $data['size'] = $attachment['size'] ?? null;
139                 $data['preview'] = $attachment['image'] ?? null;
140                 $data['description'] = $attachment['name'] ?? null;
141
142                 Post\Media::insert($data);
143         }
144
145         /**
146          * Stire attachment data
147          *
148          * @param array   $activity
149          * @param array   $item
150          */
151         private static function storeAttachments(array $activity, array $item)
152         {
153                 if (empty($activity['attachments'])) {
154                         return;
155                 }
156
157                 foreach ($activity['attachments'] as $attach) {
158                         self::storeAttachmentAsMedia($item['uri-id'], $attach);
159                 }
160         }
161
162         /**
163          * Store attachment data
164          *
165          * @param array   $activity
166          * @param array   $item
167          */
168         private static function storeQuestion(array $activity, array $item)
169         {
170                 if (empty($activity['question'])) {
171                         return;
172                 }
173                 $question = ['multiple' => $activity['question']['multiple']];
174
175                 if (!empty($activity['question']['voters'])) {
176                         $question['voters'] = $activity['question']['voters'];
177                 }
178
179                 if (!empty($activity['question']['end-time'])) {
180                         $question['end-time'] = DateTimeFormat::utc($activity['question']['end-time']);
181                 }
182
183                 Post\Question::update($item['uri-id'], $question);
184
185                 foreach ($activity['question']['options'] as $key => $option) {
186                         $option = ['name' => $option['name'], 'replies' => $option['replies']];
187                         Post\QuestionOption::update($item['uri-id'], $key, $option);
188                 }
189
190                 Logger::debug('Storing incoming question', ['type' => $activity['type'], 'uri-id' => $item['uri-id'], 'question' => $activity['question']]);
191         }
192
193         /**
194          * Updates a message
195          *
196          * @param array      $activity   Activity array
197          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
198          * @throws \ImagickException
199          */
200         public static function updateItem(array $activity)
201         {
202                 $item = Post::selectFirst(['uri', 'uri-id', 'thr-parent', 'gravity', 'post-type'], ['uri' => $activity['id']]);
203                 if (!DBA::isResult($item)) {
204                         Logger::warning('No existing item, item will be created', ['uri' => $activity['id']]);
205                         $item = self::createItem($activity);
206                         if (empty($item)) {
207                                 return;
208                         }
209
210                         self::postItem($activity, $item);
211                         return;
212                 }
213
214                 $item['changed'] = DateTimeFormat::utcNow();
215                 $item['edited'] = DateTimeFormat::utc($activity['updated']);
216
217                 $item = self::processContent($activity, $item);
218
219                 self::storeAttachments($activity, $item);
220                 self::storeQuestion($activity, $item);
221
222                 if (empty($item)) {
223                         return;
224                 }
225
226                 Post\History::add($item['uri-id'], $item);
227                 Item::update($item, ['uri' => $activity['id']]);
228
229                 Queue::remove($activity);
230
231                 if ($activity['object_type'] == 'as:Event') {
232                         $posts = Post::select(['event-id', 'uid'], ["`uri` = ? AND `event-id` > ?", $activity['id'], 0]);
233                         while ($post = DBA::fetch($posts)) {
234                                 self::updateEvent($post['event-id'], $activity);
235                         }
236                 }
237         }
238
239         /**
240          * Update an existing event
241          *
242          * @param int $event_id
243          * @param array $activity
244          */
245         private static function updateEvent(int $event_id, array $activity)
246         {
247                 $event = DBA::selectFirst('event', [], ['id' => $event_id]);
248
249                 $event['edited']   = DateTimeFormat::utc($activity['updated']);
250                 $event['summary']  = HTML::toBBCode($activity['name']);
251                 $event['desc']     = HTML::toBBCode($activity['content']);
252                 if (!empty($activity['start-time'])) {
253                         $event['start']  = DateTimeFormat::utc($activity['start-time']);
254                 }
255                 if (!empty($activity['end-time'])) {
256                         $event['finish'] = DateTimeFormat::utc($activity['end-time']);
257                 }
258                 $event['nofinish'] = empty($event['finish']);
259                 $event['location'] = $activity['location'];
260
261                 Logger::info('Updating event', ['uri' => $activity['id'], 'id' => $event_id]);
262                 Event::store($event);
263         }
264
265         /**
266          * Prepares data for a message
267          *
268          * @param array      $activity   Activity array
269          * @return array Internal item
270          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
271          * @throws \ImagickException
272          */
273         public static function createItem(array $activity): array
274         {
275                 $item = [];
276                 $item['verb'] = Activity::POST;
277                 $item['thr-parent'] = $activity['reply-to-id'];
278
279                 if ($activity['reply-to-id'] == $activity['id']) {
280                         $item['gravity'] = GRAVITY_PARENT;
281                         $item['object-type'] = Activity\ObjectType::NOTE;
282                 } else {
283                         $item['gravity'] = GRAVITY_COMMENT;
284                         $item['object-type'] = Activity\ObjectType::COMMENT;
285                 }
286
287                 if (!empty($activity['context'])) {
288                         $item['conversation'] = $activity['context'];
289                 } elseif (!empty($activity['conversation'])) {
290                         $item['conversation'] = $activity['conversation'];
291                 }
292
293                 if (!empty($item['conversation'])) {
294                         $conversation = Post::selectFirstThread(['uri'], ['conversation' => $item['conversation']]);
295                         if (!empty($conversation)) {
296                                 Logger::debug('Got conversation', ['conversation' => $item['conversation'], 'parent' => $conversation]);
297                                 $item['parent-uri'] = $conversation['uri'];
298                         }
299                 } else {
300                         $conversation = [];
301                 }
302
303                 if (empty($activity['directmessage']) && ($activity['id'] != $activity['reply-to-id']) && !Post::exists(['uri' => $activity['reply-to-id']])) {
304                         $recursion_depth = $activity['recursion-depth'] ?? 0;
305                         Logger::notice('Parent not found. Try to refetch it.', ['parent' => $activity['reply-to-id'], 'recursion-depth' => $recursion_depth]);
306                         if ($recursion_depth < DI::config()->get('system', 'max_recursion_depth')) {
307                                 $result = self::fetchMissingActivity($activity['reply-to-id'], $activity, '', Receiver::COMPLETION_AUTO);
308                                 if (empty($result) && self::isActivityGone($activity['reply-to-id'])) {
309                                         // Recursively delete this and all depending entries
310                                         Queue::deleteById($activity['entry-id']);
311                                         return [];
312                                 }
313                                 $fetch_by_worker = empty($result);
314                         } else {
315                                 Logger::notice('Recursion level is too high.', ['parent' => $activity['reply-to-id'], 'recursion-depth' => $recursion_depth]);
316                                 $fetch_by_worker = true;
317                         }
318
319                         if ($fetch_by_worker && Queue::hasWorker($activity)) {
320                                 Logger::notice('There is already a worker task to fetch the post.', ['id' => $activity['id'], 'parent' => $activity['reply-to-id']]);
321                                 $fetch_by_worker = false;
322                                 if (!empty($conversation)) {
323                                         return [];
324                                 }
325                         }
326
327                         if ($fetch_by_worker) {
328                                 Logger::notice('Fetching is done by worker.', ['parent' => $activity['reply-to-id'], 'recursion-depth' => $recursion_depth]);
329                                 $activity['recursion-depth'] = 0;
330                                 $wid = Worker::add(PRIORITY_HIGH, 'FetchMissingActivity', $activity['reply-to-id'], $activity, '', Receiver::COMPLETION_AUTO);
331                                 Queue::setWorkerId($activity, $wid);
332                                 if (!empty($conversation)) {
333                                         return [];
334                                 }
335                         } elseif (!empty($result)) {
336                                 if (($item['thr-parent'] != $result) && Post::exists(['uri' => $result])) {
337                                         $item['thr-parent'] = $result;
338                                 }
339                         }
340                 }
341
342                 $item['diaspora_signed_text'] = $activity['diaspora:comment'] ?? '';
343
344                 if (empty($conversation) && empty($activity['directmessage']) && ($item['gravity'] != GRAVITY_PARENT) && !Post::exists(['uri' => $item['thr-parent']])) {
345                         Logger::info('Parent not found, message will be discarded.', ['thr-parent' => $item['thr-parent']]);
346                         return [];
347                 }
348
349                 $item['network'] = Protocol::ACTIVITYPUB;
350                 $item['author-link'] = $activity['author'];
351                 $item['author-id'] = Contact::getIdForURL($activity['author']);
352                 $item['owner-link'] = $activity['actor'];
353                 $item['owner-id'] = Contact::getIdForURL($activity['actor']);
354
355                 if (in_array(0, $activity['receiver']) && !empty($activity['unlisted'])) {
356                         $item['private'] = Item::UNLISTED;
357                 } elseif (in_array(0, $activity['receiver'])) {
358                         $item['private'] = Item::PUBLIC;
359                 } else {
360                         $item['private'] = Item::PRIVATE;
361                 }
362
363                 if (!empty($activity['raw'])) {
364                         $item['source'] = $activity['raw'];
365                         $item['protocol'] = Conversation::PARCEL_ACTIVITYPUB;
366
367                         if (isset($activity['push'])) {
368                                 $item['direction'] = $activity['push'] ? Conversation::PUSH : Conversation::PULL;
369                         }
370                 }
371
372                 if (!empty($activity['from-relay'])) {
373                         $item['direction'] = Conversation::RELAY;
374                 }
375
376                 if ($activity['object_type'] == 'as:Article') {
377                         $item['post-type'] = Item::PT_ARTICLE;
378                 } elseif ($activity['object_type'] == 'as:Audio') {
379                         $item['post-type'] = Item::PT_AUDIO;
380                 } elseif ($activity['object_type'] == 'as:Document') {
381                         $item['post-type'] = Item::PT_DOCUMENT;
382                 } elseif ($activity['object_type'] == 'as:Event') {
383                         $item['post-type'] = Item::PT_EVENT;
384                 } elseif ($activity['object_type'] == 'as:Image') {
385                         $item['post-type'] = Item::PT_IMAGE;
386                 } elseif ($activity['object_type'] == 'as:Page') {
387                         $item['post-type'] = Item::PT_PAGE;
388                 } elseif ($activity['object_type'] == 'as:Question') {
389                         $item['post-type'] = Item::PT_POLL;
390                 } elseif ($activity['object_type'] == 'as:Video') {
391                         $item['post-type'] = Item::PT_VIDEO;
392                 } else {
393                         $item['post-type'] = Item::PT_NOTE;
394                 }
395
396                 $item['isForum'] = false;
397
398                 if (!empty($activity['thread-completion'])) {
399                         if ($activity['thread-completion'] != $item['owner-id']) {
400                                 $actor = Contact::getById($activity['thread-completion'], ['url']);
401                                 $item['causer-link'] = $actor['url'];
402                                 $item['causer-id'] = $activity['thread-completion'];
403                                 Logger::info('Use inherited actor as causer.', ['id' => $item['owner-id'], 'activity' => $activity['thread-completion'], 'owner' => $item['owner-link'], 'actor' => $actor['url']]);
404                         } else {
405                                 // Store the original actor in the "causer" fields to enable the check for ignored or blocked contacts
406                                 $item['causer-link'] = $item['owner-link'];
407                                 $item['causer-id']   = $item['owner-id'];
408                                 Logger::info('Use actor as causer.', ['id' => $item['owner-id'], 'actor' => $item['owner-link']]);
409                         }
410
411                         $item['owner-link'] = $item['author-link'];
412                         $item['owner-id'] = $item['author-id'];
413                 } else {
414                         $actor = APContact::getByURL($item['owner-link'], false);
415                         $item['isForum'] = ($actor['type'] == 'Group');
416                 }
417
418                 $item['uri'] = $activity['id'];
419
420                 if (empty($activity['published']) || empty($activity['updated'])) {
421                         DI::logger()->notice('published or updated keys are empty for activity', ['activity' => $activity, 'callstack' => System::callstack(10)]);
422                 }
423
424                 $item['created'] = DateTimeFormat::utc($activity['published'] ?? 'now');
425                 $item['edited'] = DateTimeFormat::utc($activity['updated'] ?? 'now');
426                 $guid = $activity['sc:identifier'] ?: self::getGUIDByURL($item['uri']);
427                 $item['guid'] = $activity['diaspora:guid'] ?: $guid;
428
429                 $item['uri-id'] = ItemURI::insert(['uri' => $item['uri'], 'guid' => $item['guid']]);
430                 if (empty($item['uri-id'])) {
431                         Logger::warning('Unable to get a uri-id for an item uri', ['uri' => $item['uri'], 'guid' => $item['guid']]);
432                         return [];
433                 }
434
435                 $item = self::processContent($activity, $item);
436                 if (empty($item)) {
437                         Logger::info('Message was not processed');
438                         return [];
439                 }
440
441                 $item['plink'] = $activity['alternate-url'] ?? $item['uri'];
442
443                 self::storeAttachments($activity, $item);
444                 self::storeQuestion($activity, $item);
445
446                 // We received the post via AP, so we set the protocol of the server to AP
447                 $contact = Contact::getById($item['author-id'], ['gsid']);
448                 if (!empty($contact['gsid'])) {
449                         GServer::setProtocol($contact['gsid'], Post\DeliveryData::ACTIVITYPUB);
450                 }
451
452                 if ($item['author-id'] != $item['owner-id']) {
453                         $contact = Contact::getById($item['owner-id'], ['gsid']);
454                         if (!empty($contact['gsid'])) {
455                                 GServer::setProtocol($contact['gsid'], Post\DeliveryData::ACTIVITYPUB);
456                         }
457                 }
458
459                 return $item;
460         }
461
462         /**
463          * Check if a given activity is no longer available
464          *
465          * @param string $url
466          *
467          * @return boolean
468          */
469         public static function isActivityGone(string $url): bool
470         {
471                 $curlResult = HTTPSignature::fetchRaw($url, 0);
472
473                 if (Network::isUrlBlocked($url)) {
474                         return true;
475                 }
476
477                 // @todo To ensure that the remote system is working correctly, we can check if the "Content-Type" contains JSON
478                 if (in_array($curlResult->getReturnCode(), [404])) {
479                         return true;
480                 }
481
482                 $object = json_decode($curlResult->getBody(), true);
483                 if (!empty($object)) {
484                         $activity = JsonLD::compact($object);
485                         if (JsonLD::fetchElement($activity, '@type') == 'as:Tombstone') {
486                                 return true;
487                         }                       
488                 }
489
490                 return false;
491         }
492         /**
493          * Delete items
494          *
495          * @param array $activity
496          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
497          * @throws \ImagickException
498          */
499         public static function deleteItem(array $activity)
500         {
501                 $owner = Contact::getIdForURL($activity['actor']);
502
503                 Logger::info('Deleting item', ['object' => $activity['object_id'], 'owner'  => $owner]);
504                 Item::markForDeletion(['uri' => $activity['object_id'], 'owner-id' => $owner]);
505                 Queue::remove($activity);
506         }
507
508         /**
509          * Prepare the item array for an activity
510          *
511          * @param array $activity Activity array
512          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
513          * @throws \ImagickException
514          */
515         public static function addTag(array $activity)
516         {
517                 if (empty($activity['object_content']) || empty($activity['object_id'])) {
518                         return;
519                 }
520
521                 foreach ($activity['receiver'] as $receiver) {
522                         $item = Post::selectFirst(['id', 'uri-id', 'origin', 'author-link'], ['uri' => $activity['target_id'], 'uid' => $receiver]);
523                         if (!DBA::isResult($item)) {
524                                 // We don't fetch missing content for this purpose
525                                 continue;
526                         }
527
528                         if (($item['author-link'] != $activity['actor']) && !$item['origin']) {
529                                 Logger::info('Not origin, not from the author, skipping update', ['id' => $item['id'], 'author' => $item['author-link'], 'actor' => $activity['actor']]);
530                                 continue;
531                         }
532
533                         Tag::store($item['uri-id'], Tag::HASHTAG, $activity['object_content'], $activity['object_id']);
534                         Logger::info('Tagged item', ['id' => $item['id'], 'tag' => $activity['object_content'], 'uri' => $activity['target_id'], 'actor' => $activity['actor']]);
535                 }
536         }
537
538         /**
539          * Prepare the item array for an activity
540          *
541          * @param array      $activity   Activity array
542          * @param string     $verb       Activity verb
543          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
544          * @throws \ImagickException
545          */
546         public static function createActivity(array $activity, string $verb)
547         {
548                 $activity['reply-to-id'] = $activity['object_id'];
549                 $item = self::createItem($activity);
550                 if (empty($item)) {
551                         return;
552                 }
553
554                 $item['verb'] = $verb;
555                 $item['thr-parent'] = $activity['object_id'];
556                 $item['gravity'] = GRAVITY_ACTIVITY;
557                 unset($item['post-type']);
558                 $item['object-type'] = Activity\ObjectType::NOTE;
559
560                 if (!empty($activity['content'])) {
561                         $item['body'] = HTML::toBBCode($activity['content']);
562                 }
563
564                 $item['diaspora_signed_text'] = $activity['diaspora:like'] ?? '';
565
566                 self::postItem($activity, $item);
567         }
568
569         /**
570          * Fetch the Uri-Id of a post for the "featured" collection
571          *
572          * @param array $activity
573          * @return null|int
574          */
575         private static function getUriIdForFeaturedCollection(array $activity)
576         {
577                 $actor = APContact::getByURL($activity['actor']);
578                 if (empty($actor)) {
579                         return null;
580                 }
581
582                 // Refetch the account when the "featured" collection is missing.
583                 // This can be removed in a future version (end of 2022 should be good).
584                 if (empty($actor['featured'])) {
585                         $actor = APContact::getByURL($activity['actor'], true);
586                         if (empty($actor)) {
587                                 return null;
588                         }
589                 }
590
591                 $parent = Post::selectFirst(['uri-id'], ['uri' => $activity['object_id']]);
592                 if (empty($parent['uri-id'])) {
593                         if (self::fetchMissingActivity($activity['object_id'], $activity, '', Receiver::COMPLETION_AUTO)) {
594                                 $parent = Post::selectFirst(['uri-id'], ['uri' => $activity['object_id']]);
595                         }
596                 }
597
598                 if (!empty($parent['uri-id'])) {
599                         return $parent['uri-id'];
600                 }
601
602                 return null;
603         }
604
605         /**
606          * Add a post to the "Featured" collection
607          *
608          * @param array $activity
609          */
610         public static function addToFeaturedCollection(array $activity)
611         {
612                 $uriid = self::getUriIdForFeaturedCollection($activity);
613                 if (empty($uriid)) {
614                         return;
615                 }
616
617                 Logger::debug('Add post to featured collection', ['uri-id' => $uriid]);
618
619                 Post\Collection::add($uriid, Post\Collection::FEATURED);
620                 Queue::remove($activity);
621         }
622
623         /**
624          * Remove a post to the "Featured" collection
625          *
626          * @param array $activity
627          */
628         public static function removeFromFeaturedCollection(array $activity)
629         {
630                 $uriid = self::getUriIdForFeaturedCollection($activity);
631                 if (empty($uriid)) {
632                         return;
633                 }
634
635                 Logger::debug('Remove post from featured collection', ['uri-id' => $uriid]);
636
637                 Post\Collection::remove($uriid, Post\Collection::FEATURED);
638                 Queue::remove($activity);
639         }
640
641         /**
642          * Create an event
643          *
644          * @param array $activity Activity array
645          * @param array $item
646          *
647          * @return int event id
648          * @throws \Exception
649          */
650         public static function createEvent(array $activity, array $item): int
651         {
652                 $event['summary']   = HTML::toBBCode($activity['name'] ?: $activity['summary']);
653                 $event['desc']      = HTML::toBBCode($activity['content']);
654                 if (!empty($activity['start-time'])) {
655                         $event['start']  = DateTimeFormat::utc($activity['start-time']);
656                 }
657                 if (!empty($activity['end-time'])) {
658                         $event['finish'] = DateTimeFormat::utc($activity['end-time']);
659                 }
660                 $event['nofinish']  = empty($event['finish']);
661                 $event['location']  = $activity['location'];
662                 $event['cid']       = $item['contact-id'];
663                 $event['uid']       = $item['uid'];
664                 $event['uri']       = $item['uri'];
665                 $event['edited']    = $item['edited'];
666                 $event['private']   = $item['private'];
667                 $event['guid']      = $item['guid'];
668                 $event['plink']     = $item['plink'];
669                 $event['network']   = $item['network'];
670                 $event['protocol']  = $item['protocol'];
671                 $event['direction'] = $item['direction'];
672                 $event['source']    = $item['source'];
673
674                 $ev = DBA::selectFirst('event', ['id'], ['uri' => $item['uri'], 'uid' => $item['uid']]);
675                 if (DBA::isResult($ev)) {
676                         $event['id'] = $ev['id'];
677                 }
678
679                 $event_id = Event::store($event);
680
681                 Logger::info('Event was stored', ['id' => $event_id]);
682
683                 return $event_id;
684         }
685
686         /**
687          * Process the content
688          *
689          * @param array $activity Activity array
690          * @param array $item
691          * @return array|bool Returns the item array or false if there was an unexpected occurrence
692          * @throws \Exception
693          */
694         private static function processContent(array $activity, array $item)
695         {
696                 if (!empty($activity['mediatype']) && ($activity['mediatype'] == 'text/markdown')) {
697                         $item['title'] = strip_tags($activity['name']);
698                         $content = Markdown::toBBCode($activity['content']);
699                 } elseif (!empty($activity['mediatype']) && ($activity['mediatype'] == 'text/bbcode')) {
700                         $item['title'] = $activity['name'];
701                         $content = $activity['content'];
702                 } else {
703                         // By default assume "text/html"
704                         $item['title'] = HTML::toBBCode($activity['name'] ?? '');
705                         $content = HTML::toBBCode($activity['content'] ?? '');
706                 }
707
708                 $item['title'] = trim(BBCode::toPlaintext($item['title']));
709
710                 if (!empty($activity['languages'])) {
711                         $item['language'] = self::processLanguages($activity['languages']);
712                 }
713
714                 if (!empty($activity['emojis'])) {
715                         $content = self::replaceEmojis($item['uri-id'], $content, $activity['emojis']);
716                 }
717
718                 $content = self::addMentionLinks($content, $activity['tags']);
719
720                 if (!empty($activity['source'])) {
721                         $item['body'] = $activity['source'];
722                         $item['raw-body'] = $content;
723                         $item['body'] = Item::improveSharedDataInBody($item);
724                 } else {
725                         $parent_uri = $item['parent-uri'] ?? $item['thr-parent'];
726                         if (empty($activity['directmessage']) && ($parent_uri != $item['uri']) && ($item['gravity'] == GRAVITY_COMMENT)) {
727                                 $parent = Post::selectFirst(['id', 'uri-id', 'private', 'author-link', 'alias'], ['uri' => $parent_uri]);
728                                 if (!DBA::isResult($parent)) {
729                                         Logger::warning('Unknown parent item.', ['uri' => $parent_uri]);
730                                         return false;
731                                 }
732                                 if (($item['private'] == Item::PRIVATE) && ($parent['private'] != Item::PRIVATE)) {
733                                         Logger::warning('Item is private but the parent is not. Dropping.', ['item-uri' => $item['uri'], 'thr-parent' => $item['thr-parent']]);
734                                         return false;
735                                 }
736
737                                 $content = self::removeImplicitMentionsFromBody($content, $parent);
738                         }
739                         $item['content-warning'] = HTML::toBBCode($activity['summary'] ?? '');
740                         $item['raw-body'] = $item['body'] = $content;
741                 }
742
743                 self::storeFromBody($item);
744                 self::storeTags($item['uri-id'], $activity['tags']);
745
746                 self::storeReceivers($item['uri-id'], $activity['receiver_urls'] ?? []);
747
748                 $item['location'] = $activity['location'];
749
750                 if (!empty($activity['latitude']) && !empty($activity['longitude'])) {
751                         $item['coord'] = $activity['latitude'] . ' ' . $activity['longitude'];
752                 }
753
754                 $item['app'] = $activity['generator'];
755
756                 return $item;
757         }
758
759         /**
760          * Store hashtags and mentions
761          *
762          * @param array $item
763          */
764         private static function storeFromBody(array $item)
765         {
766                 // Make sure to delete all existing tags (can happen when called via the update functionality)
767                 DBA::delete('post-tag', ['uri-id' => $item['uri-id']]);
768
769                 Tag::storeFromBody($item['uri-id'], $item['body'], '@!');
770         }
771
772         /**
773          * Generate a GUID out of an URL of an ActivityPub post.
774          *
775          * @param string $url message URL
776          * @return string with GUID
777          */
778         private static function getGUIDByURL(string $url): string
779         {
780                 $parsed = parse_url($url);
781
782                 $host_hash = hash('crc32', $parsed['host']);
783
784                 unset($parsed["scheme"]);
785                 unset($parsed["host"]);
786
787                 $path = implode("/", $parsed);
788
789                 return $host_hash . '-'. hash('fnv164', $path) . '-'. hash('joaat', $path);
790         }
791
792         /**
793          * Checks if an incoming message is wanted
794          *
795          * @param array $activity
796          * @param array $item
797          * @return boolean Is the message wanted?
798          */
799         private static function isSolicitedMessage(array $activity, array $item): bool
800         {
801                 // The checks are split to improve the support when searching why a message was accepted.
802                 if (count($activity['receiver']) != 1) {
803                         // The message has more than one receiver, so it is wanted.
804                         Logger::debug('Message has got several receivers - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
805                         return true;
806                 }
807
808                 if ($item['private'] == Item::PRIVATE) {
809                         // We only look at public posts here. Private posts are expected to be intentionally posted to the single receiver.
810                         Logger::debug('Message is private - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
811                         return true;
812                 }
813
814                 if (!empty($activity['from-relay'])) {
815                         // We check relay posts at another place. When it arrived here, the message is already checked.
816                         Logger::debug('Message is a relay post that is already checked - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
817                         return true;
818                 }
819
820                 if (in_array($activity['completion-mode'] ?? Receiver::COMPLETION_NONE, [Receiver::COMPLETION_MANUAL, Receiver::COMPLETION_ANNOUCE])) {
821                         // Manual completions and completions caused by reshares are allowed without any further checks.
822                         Logger::debug('Message is in completion mode - accepted', ['mode' => $activity['completion-mode'], 'uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
823                         return true;
824                 }
825
826                 if ($item['gravity'] != GRAVITY_PARENT) {
827                         // We cannot reliably check at this point if a comment or activity belongs to an accepted post or needs to be fetched
828                         // This can possibly be improved in the future.
829                         Logger::debug('Message is no parent - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
830                         return true;
831                 }
832
833                 $tags = array_column(Tag::getByURIId($item['uri-id'], [Tag::HASHTAG]), 'name');
834                 if (Relay::isSolicitedPost($tags, $item['body'], $item['author-id'], $item['uri'], Protocol::ACTIVITYPUB)) {
835                         Logger::debug('Post is accepted because of the relay settings', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
836                         return true;
837                 } else {
838                         return false;
839                 }
840         }
841
842         /**
843          * Creates an item post
844          *
845          * @param array $activity Activity data
846          * @param array $item     item array
847          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
848          * @throws \ImagickException
849          */
850         public static function postItem(array $activity, array $item)
851         {
852                 if (empty($item)) {
853                         return;
854                 }
855
856                 $stored = false;
857                 $success = false;
858                 ksort($activity['receiver']);
859
860                 if (!self::isSolicitedMessage($activity, $item)) {
861                         DBA::delete('item-uri', ['id' => $item['uri-id']]);
862                         return;
863                 }
864
865                 foreach ($activity['receiver'] as $receiver) {
866                         if ($receiver == -1) {
867                                 continue;
868                         }
869
870                         $item['uid'] = $receiver;
871
872                         $type = $activity['reception_type'][$receiver] ?? Receiver::TARGET_UNKNOWN;
873                         switch($type) {
874                                 case Receiver::TARGET_TO:
875                                         $item['post-reason'] = Item::PR_TO;
876                                         break;
877                                 case Receiver::TARGET_CC:
878                                         $item['post-reason'] = Item::PR_CC;
879                                         break;
880                                 case Receiver::TARGET_BTO:
881                                         $item['post-reason'] = Item::PR_BTO;
882                                         break;
883                                 case Receiver::TARGET_BCC:
884                                         $item['post-reason'] = Item::PR_BCC;
885                                         break;
886                                 case Receiver::TARGET_FOLLOWER:
887                                         $item['post-reason'] = Item::PR_FOLLOWER;
888                                         break;
889                                 case Receiver::TARGET_ANSWER:
890                                         $item['post-reason'] = Item::PR_COMMENT;
891                                         break;
892                                 case Receiver::TARGET_GLOBAL:
893                                         $item['post-reason'] = Item::PR_GLOBAL;
894                                         break;
895                                 default:
896                                         $item['post-reason'] = Item::PR_NONE;
897                         }
898
899                         if (!empty($activity['from-relay'])) {
900                                 $item['post-reason'] = Item::PR_RELAY;
901                         } elseif (!empty($activity['thread-completion'])) {
902                                 $item['post-reason'] = Item::PR_FETCHED;
903                         }
904
905                         if ($item['isForum'] ?? false) {
906                                 $item['contact-id'] = Contact::getIdForURL($activity['actor'], $receiver);
907                         } else {
908                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver);
909                         }
910
911                         if (($receiver != 0) && empty($item['contact-id'])) {
912                                 $item['contact-id'] = Contact::getIdForURL($activity['author']);
913                         }
914
915                         if (!empty($activity['directmessage'])) {
916                                 self::postMail($activity, $item);
917                                 continue;
918                         }
919
920                         if (!($item['isForum'] ?? false) && ($receiver != 0) && ($item['gravity'] == GRAVITY_PARENT) && !Contact::isSharingByURL($activity['author'], $receiver)) {
921                                 if ($item['post-reason'] == Item::PR_BCC) {
922                                         Logger::info('Top level post via BCC from a non sharer, ignoring', ['uid' => $receiver, 'contact' => $item['contact-id']]);
923                                         continue;
924                                 }
925
926                                 if (
927                                         !empty($activity['thread-children-type'])
928                                         && in_array($activity['thread-children-type'], Receiver::ACTIVITY_TYPES)
929                                         && DI::pConfig()->get($receiver, 'system', 'accept_only_sharer') != Item::COMPLETION_LIKE
930                                 ) {
931                                         Logger::info('Top level post from thread completion from a non sharer had been initiated via an activity, ignoring',
932                                                 ['type' => $activity['thread-children-type'], 'user' => $item['uid'], 'causer' => $item['causer-link'], 'author' => $activity['author'], 'url' => $item['uri']]);
933                                         continue;
934                                 }
935                         }
936
937                         $is_forum = false;
938
939                         if ($receiver != 0) {
940                                 $user = User::getById($receiver, ['account-type']);
941                                 if (!empty($user['account-type'])) {
942                                         $is_forum = ($user['account-type'] == User::ACCOUNT_TYPE_COMMUNITY);
943                                 }
944                         }
945
946                         if (!$is_forum && DI::pConfig()->get($receiver, 'system', 'accept_only_sharer') == Item::COMPLETION_NONE && ($receiver != 0) && ($item['gravity'] == GRAVITY_PARENT)) {
947                                 $skip = !Contact::isSharingByURL($activity['author'], $receiver);
948
949                                 if ($skip && (($activity['type'] == 'as:Announce') || ($item['isForum'] ?? false))) {
950                                         $skip = !Contact::isSharingByURL($activity['actor'], $receiver);
951                                 }
952
953                                 if ($skip) {
954                                         Logger::info('Skipping post', ['uid' => $receiver, 'url' => $item['uri']]);
955                                         continue;
956                                 }
957
958                                 Logger::info('Accepting post', ['uid' => $receiver, 'url' => $item['uri']]);
959                         }
960
961                         if (($item['gravity'] != GRAVITY_ACTIVITY) && ($activity['object_type'] == 'as:Event')) {
962                                 $event_id = self::createEvent($activity, $item);
963
964                                 $item = Event::getItemArrayForImportedId($event_id, $item);
965                         }
966
967                         $item_id = Item::insert($item);
968                         if ($item_id) {
969                                 Logger::info('Item insertion successful', ['user' => $item['uid'], 'item_id' => $item_id]);
970                                 $success = true;
971                         } else {
972                                 Logger::notice('Item insertion aborted', ['uri' => $item['uri'], 'uid' => $item['uid']]);
973                                 if (Item::isTooOld($item) || !Item::isValid($item)) {
974                                         Queue::remove($activity);
975                                 }
976                         }
977
978                         if ($item['uid'] == 0) {
979                                 $stored = $item_id;
980                         }
981                 }
982
983                 if ($success) {
984                         Queue::remove($activity);
985
986                         if (Queue::hasChildren($item['uri'])) {
987                                 Worker::add(PRIORITY_HIGH, 'ProcessReplyByUri', $item['uri']);
988                         }
989                 }
990
991                 // Store send a follow request for every reshare - but only when the item had been stored
992                 if ($stored && ($item['private'] != Item::PRIVATE) && ($item['gravity'] == GRAVITY_PARENT) && !empty($item['author-link']) && ($item['author-link'] != $item['owner-link'])) {
993                         $author = APContact::getByURL($item['owner-link'], false);
994                         // We send automatic follow requests for reshared messages. (We don't need though for forum posts)
995                         if ($author['type'] != 'Group') {
996                                 Logger::info('Send follow request', ['uri' => $item['uri'], 'stored' => $stored, 'to' => $item['author-link']]);
997                                 ActivityPub\Transmitter::sendFollowObject($item['uri'], $item['author-link']);
998                         }
999                 }
1000         }
1001
1002         /**
1003          * Store tags and mentions into the tag table
1004          *
1005          * @param integer $uriid
1006          * @param array $tags
1007          */
1008         private static function storeTags(int $uriid, array $tags = null)
1009         {
1010                 foreach ($tags as $tag) {
1011                         if (empty($tag['name']) || empty($tag['type']) || !in_array($tag['type'], ['Mention', 'Hashtag'])) {
1012                                 continue;
1013                         }
1014
1015                         $hash = substr($tag['name'], 0, 1);
1016
1017                         if ($tag['type'] == 'Mention') {
1018                                 if (in_array($hash, [Tag::TAG_CHARACTER[Tag::MENTION],
1019                                         Tag::TAG_CHARACTER[Tag::EXCLUSIVE_MENTION],
1020                                         Tag::TAG_CHARACTER[Tag::IMPLICIT_MENTION]])) {
1021                                         $tag['name'] = substr($tag['name'], 1);
1022                                 }
1023                                 $type = Tag::IMPLICIT_MENTION;
1024
1025                                 if (!empty($tag['href'])) {
1026                                         $apcontact = APContact::getByURL($tag['href']);
1027                                         if (!empty($apcontact['name']) || !empty($apcontact['nick'])) {
1028                                                 $tag['name'] = $apcontact['name'] ?: $apcontact['nick'];
1029                                         }
1030                                 }
1031                         } elseif ($tag['type'] == 'Hashtag') {
1032                                 if ($hash == Tag::TAG_CHARACTER[Tag::HASHTAG]) {
1033                                         $tag['name'] = substr($tag['name'], 1);
1034                                 }
1035                                 $type = Tag::HASHTAG;
1036                         }
1037
1038                         if (empty($tag['name'])) {
1039                                 continue;
1040                         }
1041
1042                         Tag::store($uriid, $type, $tag['name'], $tag['href']);
1043                 }
1044         }
1045
1046         public static function storeReceivers(int $uriid, array $receivers)
1047         {
1048                 foreach (['as:to' => Tag::TO, 'as:cc' => Tag::CC, 'as:bto' => Tag::BTO, 'as:bcc' => Tag::BCC] as $element => $type) {
1049                         if (!empty($receivers[$element])) {
1050                                 foreach ($receivers[$element] as $receiver) {
1051                                         if ($receiver == ActivityPub::PUBLIC_COLLECTION) {
1052                                                 $name = Receiver::PUBLIC_COLLECTION;
1053                                         } else {
1054                                                 $name = trim(parse_url($receiver, PHP_URL_PATH), '/');
1055                                         }
1056
1057                                         $target = Tag::getTargetType($receiver);
1058                                         Logger::debug('Got target type', ['type' => $target, 'url' => $receiver]);
1059                                         Tag::store($uriid, $type, $name, $receiver, $target);
1060                                 }
1061                         }
1062                 }
1063         }
1064
1065         /**
1066          * Creates an mail post
1067          *
1068          * @param array $activity Activity data
1069          * @param array $item     item array
1070          * @return int|bool New mail table row id or false on error
1071          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1072          */
1073         private static function postMail(array $activity, array $item)
1074         {
1075                 if (($item['gravity'] != GRAVITY_PARENT) && !DBA::exists('mail', ['uri' => $item['thr-parent'], 'uid' => $item['uid']])) {
1076                         Logger::info('Parent not found, mail will be discarded.', ['uid' => $item['uid'], 'uri' => $item['thr-parent']]);
1077                         return false;
1078                 }
1079
1080                 Logger::info('Direct Message', $item);
1081
1082                 $msg = [];
1083                 $msg['uid'] = $item['uid'];
1084
1085                 $msg['contact-id'] = $item['contact-id'];
1086
1087                 $contact = Contact::getById($item['contact-id'], ['name', 'url', 'photo']);
1088                 $msg['from-name'] = $contact['name'];
1089                 $msg['from-url'] = $contact['url'];
1090                 $msg['from-photo'] = $contact['photo'];
1091
1092                 $msg['uri'] = $item['uri'];
1093                 $msg['created'] = $item['created'];
1094
1095                 $parent = DBA::selectFirst('mail', ['parent-uri', 'title'], ['uri' => $item['thr-parent']]);
1096                 if (DBA::isResult($parent)) {
1097                         $msg['parent-uri'] = $parent['parent-uri'];
1098                         $msg['title'] = $parent['title'];
1099                 } else {
1100                         $msg['parent-uri'] = $item['thr-parent'];
1101
1102                         if (!empty($item['title'])) {
1103                                 $msg['title'] = $item['title'];
1104                         } elseif (!empty($item['content-warning'])) {
1105                                 $msg['title'] = $item['content-warning'];
1106                         } else {
1107                                 // Trying to generate a title out of the body
1108                                 $title = $item['body'];
1109
1110                                 while (preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $title, $matches)) {
1111                                         $title = $matches[3];
1112                                 }
1113
1114                                 $title = trim(BBCode::toPlaintext($title));
1115
1116                                 if (strlen($title) > 20) {
1117                                         $title = substr($title, 0, 20) . '...';
1118                                 }
1119
1120                                 $msg['title'] = $title;
1121                         }
1122                 }
1123                 $msg['body'] = $item['body'];
1124
1125                 return Mail::insert($msg);
1126         }
1127
1128         /**
1129          * Fetch featured posts from a contact with the given url
1130          *
1131          * @param string $url
1132          * @return void
1133          */
1134         public static function fetchFeaturedPosts(string $url)
1135         {
1136                 Logger::info('Fetch featured posts', ['contact' => $url]);
1137
1138                 $apcontact = APContact::getByURL($url);
1139                 if (empty($apcontact['featured'])) {
1140                         Logger::info('Contact does not have a featured collection', ['contact' => $url]);
1141                         return;
1142                 }
1143
1144                 $pcid = Contact::getIdForURL($url, 0, false);
1145                 if (empty($pcid)) {
1146                         Logger::info('Contact not found', ['contact' => $url]);
1147                         return;
1148                 }
1149
1150                 $posts = Post\Collection::selectToArrayForContact($pcid, Post\Collection::FEATURED);
1151                 if (!empty($posts)) {
1152                         $old_featured = array_column($posts, 'uri-id');
1153                 } else {
1154                         $old_featured = [];
1155                 }
1156
1157                 $featured = ActivityPub::fetchItems($apcontact['featured']);
1158                 if (empty($featured)) {
1159                         Logger::info('Contact does not have featured posts', ['contact' => $url]);
1160
1161                         foreach ($old_featured as $uri_id) {
1162                                 Post\Collection::remove($uri_id, Post\Collection::FEATURED);
1163                                 Logger::debug('Removed no longer featured post', ['uri-id' => $uri_id, 'contact' => $url]);
1164                         }
1165                         return;
1166                 }
1167
1168                 $new = 0;
1169                 $old = 0;
1170
1171                 foreach ($featured as $post) {
1172                         if (empty($post['id'])) {
1173                                 continue;
1174                         }
1175                         $id = Item::fetchByLink($post['id']);
1176                         if (!empty($id)) {
1177                                 $item = Post::selectFirst(['uri-id', 'featured'], ['id' => $id]);
1178                                 if (!empty($item['uri-id'])) {
1179                                         if (!$item['featured']) {
1180                                                 Post\Collection::add($item['uri-id'], Post\Collection::FEATURED);
1181                                                 Logger::debug('Added featured post', ['uri-id' => $item['uri-id'], 'contact' => $url]);
1182                                                 $new++;
1183                                         } else {
1184                                                 Logger::debug('Post already had been featured', ['uri-id' => $item['uri-id'], 'contact' => $url]);
1185                                                 $old++;
1186                                         }
1187
1188                                         $index = array_search($item['uri-id'], $old_featured);
1189                                         if (!($index === false)) {
1190                                                 unset($old_featured[$index]);
1191                                         }
1192                                 }
1193                         }
1194                 }
1195
1196                 foreach ($old_featured as $uri_id) {
1197                         Post\Collection::remove($uri_id, Post\Collection::FEATURED);
1198                         Logger::debug('Removed no longer featured post', ['uri-id' => $uri_id, 'contact' => $url]);
1199                 }
1200
1201                 Logger::info('Fetched featured posts', ['new' => $new, 'old' => $old, 'contact' => $url]);
1202         }
1203
1204         public static function fetchCachedActivity(string $url, int $uid): array
1205         {
1206                 $cachekey = self::CACHEKEY_FETCH_ACTIVITY . $uid . ':' . $url;
1207                 $object = DI::cache()->get($cachekey);
1208
1209                 if (!is_null($object)) {
1210                         if (!empty($object)) {
1211                                 Logger::debug('Fetch from cache', ['url' => $url, 'uid' => $uid]);
1212                         } else {
1213                                 Logger::debug('Fetch from negative cache', ['url' => $url, 'uid' => $uid]);
1214                         }
1215                         return $object;
1216                 }
1217
1218                 $object = ActivityPub::fetchContent($url, $uid);
1219                 if (empty($object)) {
1220                         Logger::notice('Activity was not fetchable, aborting.', ['url' => $url, 'uid' => $uid]);
1221                         // We perform negative caching.
1222                         DI::cache()->set($cachekey, [], Duration::FIVE_MINUTES);
1223                         return [];
1224                 }
1225
1226                 if (empty($object['id'])) {
1227                         Logger::notice('Activity has got not id, aborting. ', ['url' => $url, 'object' => $object]);
1228                         return [];
1229                 }
1230                 DI::cache()->set($cachekey, $object, Duration::FIVE_MINUTES);
1231
1232                 Logger::debug('Activity was fetched successfully', ['url' => $url, 'uid' => $uid]);
1233
1234                 return $object;
1235         }
1236
1237         /**
1238          * Fetches missing posts
1239          *
1240          * @param string     $url         message URL
1241          * @param array      $child       activity array with the child of this message
1242          * @param string     $relay_actor Relay actor
1243          * @param int        $completion  Completion mode, see Receiver::COMPLETION_*
1244          * @return string fetched message URL
1245          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1246          * @throws \ImagickException
1247          */
1248         public static function fetchMissingActivity(string $url, array $child = [], string $relay_actor = '', int $completion = Receiver::COMPLETION_MANUAL): string
1249         {
1250                 if (!empty($child['receiver'])) {
1251                         $uid = ActivityPub\Receiver::getFirstUserFromReceivers($child['receiver']);
1252                 } else {
1253                         $uid = 0;
1254                 }
1255
1256                 $object = self::fetchCachedActivity($url, $uid);
1257                 if (empty($object)) {
1258                         return '';
1259                 }
1260
1261                 $signer = [];
1262
1263                 if (!empty($object['attributedTo'])) {
1264                         $attributed_to = $object['attributedTo'];
1265                         if (is_array($attributed_to)) {
1266                                 $compacted = JsonLD::compact($object);
1267                                 $attributed_to = JsonLD::fetchElement($compacted, 'as:attributedTo', '@id');
1268                         }
1269                         $signer[] = $attributed_to;     
1270                 }
1271
1272                 if (!empty($object['actor'])) {
1273                         $object_actor = $object['actor'];
1274                 } elseif (!empty($attributed_to)) {
1275                         $object_actor = $attributed_to;
1276                 } else {
1277                         // Shouldn't happen
1278                         $object_actor = '';
1279                 }
1280
1281                 $signer[] = $object_actor;
1282
1283                 if (!empty($child['author'])) {
1284                         $actor = $child['author'];
1285                         $signer[] = $actor;
1286                 } else {
1287                         $actor = $object_actor;
1288                 }
1289
1290                 if (!empty($object['published'])) {
1291                         $published = $object['published'];
1292                 } elseif (!empty($child['published'])) {
1293                         $published = $child['published'];
1294                 } else {
1295                         $published = DateTimeFormat::utcNow();
1296                 }
1297
1298                 $activity = [];
1299                 $activity['@context'] = $object['@context'] ?? ActivityPub::CONTEXT;
1300                 unset($object['@context']);
1301                 $activity['id'] = $object['id'];
1302                 $activity['to'] = $object['to'] ?? [];
1303                 $activity['cc'] = $object['cc'] ?? [];
1304                 $activity['actor'] = $actor;
1305                 $activity['object'] = $object;
1306                 $activity['published'] = $published;
1307                 $activity['type'] = 'Create';
1308
1309                 $ldactivity = JsonLD::compact($activity);
1310
1311                 $ldactivity['recursion-depth'] = !empty($child['recursion-depth']) ? $child['recursion-depth'] + 1 : 1;
1312
1313                 if (!empty($relay_actor)) {
1314                         $ldactivity['thread-completion'] = $ldactivity['from-relay'] = Contact::getIdForURL($relay_actor);
1315                         $ldactivity['completion-mode']   = Receiver::COMPLETION_RELAY;
1316                 } elseif (!empty($child['thread-completion'])) {
1317                         $ldactivity['thread-completion'] = $child['thread-completion'];
1318                         $ldactivity['completion-mode']   = $child['completion-mode'] ?? Receiver::COMPLETION_NONE;
1319                 } else {
1320                         $ldactivity['thread-completion'] = Contact::getIdForURL($actor);
1321                         $ldactivity['completion-mode']   = $completion;
1322                 }
1323
1324                 if (!empty($child['type'])) {
1325                         $ldactivity['thread-children-type'] = $child['type'];
1326                 }
1327
1328                 if (!empty($relay_actor) && !self::acceptIncomingMessage($ldactivity, $object['id'])) {
1329                         return '';
1330                 }
1331
1332                 ActivityPub\Receiver::processActivity($ldactivity, json_encode($activity), $uid, true, false, $signer);
1333
1334                 Logger::notice('Activity had been fetched and processed.', ['url' => $url, 'object' => $activity['id']]);
1335
1336                 return $activity['id'];
1337         }
1338
1339         /**
1340          * Test if incoming relay messages should be accepted
1341          *
1342          * @param array $activity activity array
1343          * @param string $id      object ID
1344          * @return boolean true if message is accepted
1345          */
1346         private static function acceptIncomingMessage(array $activity, string $id): bool
1347         {
1348                 if (empty($activity['as:object'])) {
1349                         Logger::info('No object field in activity - accepted', ['id' => $id]);
1350                         return true;
1351                 }
1352
1353                 $replyto = JsonLD::fetchElement($activity['as:object'], 'as:inReplyTo', '@id');
1354                 $uriid = ItemURI::getIdByURI($replyto ?? '');
1355                 if (Post::exists(['uri-id' => $uriid])) {
1356                         Logger::info('Post is a reply to an existing post - accepted', ['id' => $id, 'uri-id' => $uriid, 'replyto' => $replyto]);
1357                         return true;
1358                 }
1359
1360                 $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
1361                 $authorid = Contact::getIdForURL($attributed_to);
1362
1363                 $body = HTML::toBBCode(JsonLD::fetchElement($activity['as:object'], 'as:content', '@value') ?? '');
1364
1365                 $messageTags = [];
1366                 $tags = Receiver::processTags(JsonLD::fetchElementArray($activity['as:object'], 'as:tag') ?? []);
1367                 if (!empty($tags)) {
1368                         foreach ($tags as $tag) {
1369                                 if ($tag['type'] != 'Hashtag') {
1370                                         continue;
1371                                 }
1372                                 $messageTags[] = ltrim(mb_strtolower($tag['name']), '#');
1373                         }
1374                 }
1375
1376                 return Relay::isSolicitedPost($messageTags, $body, $authorid, $id, Protocol::ACTIVITYPUB);
1377         }
1378
1379         /**
1380          * perform a "follow" request
1381          *
1382          * @param array $activity
1383          * @return void
1384          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1385          * @throws \ImagickException
1386          */
1387         public static function followUser(array $activity)
1388         {
1389                 $uid = User::getIdForURL($activity['object_id']);
1390                 if (empty($uid)) {
1391                         Queue::remove($activity);
1392                         return;
1393                 }
1394
1395                 $owner = User::getOwnerDataById($uid);
1396                 if (empty($owner)) {
1397                         return;
1398                 }
1399
1400                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1401                 if (!empty($cid)) {
1402                         self::switchContact($cid);
1403                         Contact::update(['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
1404                 }
1405
1406                 $item = [
1407                         'author-id' => Contact::getIdForURL($activity['actor']),
1408                         'author-link' => $activity['actor'],
1409                 ];
1410
1411                 // Ensure that the contact has got the right network type
1412                 self::switchContact($item['author-id']);
1413
1414                 $result = Contact::addRelationship($owner, [], $item, false, $activity['content'] ?? '');
1415                 if ($result === true) {
1416                         ActivityPub\Transmitter::sendContactAccept($item['author-link'], $activity['id'], $owner['uid']);
1417                 }
1418
1419                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1420                 if (empty($cid)) {
1421                         return;
1422                 }
1423
1424                 if ($result && DI::config()->get('system', 'transmit_pending_events') && ($owner['contact-type'] == Contact::TYPE_COMMUNITY)) {
1425                         self::transmitPendingEvents($cid, $owner['uid']);
1426                 }
1427
1428                 if (empty($contact)) {
1429                         Contact::update(['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
1430                 }
1431                 Logger::notice('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
1432                 Queue::remove($activity);
1433         }
1434
1435         /**
1436          * Transmit pending events to the new follower
1437          *
1438          * @param integer $cid Contact id
1439          * @param integer $uid User id
1440          * @return void
1441          */
1442         private static function transmitPendingEvents(int $cid, int $uid)
1443         {
1444                 $account = DBA::selectFirst('account-user-view', ['ap-inbox', 'ap-sharedinbox'], ['id' => $cid]);
1445                 $inbox = $account['ap-sharedinbox'] ?: $account['ap-inbox'];
1446
1447                 $events = DBA::select('event', ['id'], ["`uid` = ? AND `start` > ? AND `type` != ?", $uid, DateTimeFormat::utcNow(), 'birthday']);
1448                 while ($event = DBA::fetch($events)) {
1449                         $post = Post::selectFirst(['id', 'uri-id', 'created'], ['event-id' => $event['id']]);
1450                         if (empty($post)) {
1451                                 continue;
1452                         }
1453                         if (DI::config()->get('system', 'bulk_delivery')) {
1454                                 Post\Delivery::add($post['uri-id'], $uid, $inbox, $post['created'], Delivery::POST, [$cid]);
1455                                 Worker::add(PRIORITY_HIGH, 'APDelivery', '', 0, $inbox, 0);
1456                         } else {
1457                                 Worker::add(PRIORITY_HIGH, 'APDelivery', Delivery::POST, $post['id'], $inbox, $uid, [$cid], $post['uri-id']);
1458                         }
1459                 }
1460         }
1461
1462         /**
1463          * Update the given profile
1464          *
1465          * @param array $activity
1466          * @throws \Exception
1467          */
1468         public static function updatePerson(array $activity)
1469         {
1470                 if (empty($activity['object_id'])) {
1471                         return;
1472                 }
1473
1474                 Logger::info('Updating profile', ['object' => $activity['object_id']]);
1475                 Contact::updateFromProbeByURL($activity['object_id']);
1476                 Queue::remove($activity);
1477         }
1478
1479         /**
1480          * Delete the given profile
1481          *
1482          * @param array $activity
1483          * @return void
1484          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1485          */
1486         public static function deletePerson(array $activity)
1487         {
1488                 if (empty($activity['object_id']) || empty($activity['actor'])) {
1489                         Logger::info('Empty object id or actor.');
1490                         return;
1491                 }
1492
1493                 if ($activity['object_id'] != $activity['actor']) {
1494                         Logger::info('Object id does not match actor.');
1495                         return;
1496                 }
1497
1498                 $contacts = DBA::select('contact', ['id'], ['nurl' => Strings::normaliseLink($activity['object_id'])]);
1499                 while ($contact = DBA::fetch($contacts)) {
1500                         Contact::remove($contact['id']);
1501                 }
1502                 DBA::close($contacts);
1503
1504                 Logger::info('Deleted contact', ['object' => $activity['object_id']]);
1505                 Queue::remove($activity);
1506         }
1507
1508         /**
1509          * Blocks the user by the contact
1510          *
1511          * @param array $activity
1512          * @return void
1513          * @throws \Exception
1514          */
1515         public static function blockAccount(array $activity)
1516         {
1517                 $cid = Contact::getIdForURL($activity['actor']);
1518                 if (empty($cid)) {
1519                         return;
1520                 }
1521
1522                 $uid = User::getIdForURL($activity['object_id']);
1523                 if (empty($uid)) {
1524                         return;
1525                 }
1526
1527                 Contact\User::setIsBlocked($cid, $uid, true);
1528
1529                 Logger::info('Contact blocked user', ['contact' => $cid, 'user' => $uid]);
1530                 Queue::remove($activity);
1531         }
1532
1533         /**
1534          * Unblocks the user by the contact
1535          *
1536          * @param array $activity
1537          * @return void
1538          * @throws \Exception
1539          */
1540         public static function unblockAccount(array $activity)
1541         {
1542                 $cid = Contact::getIdForURL($activity['actor']);
1543                 if (empty($cid)) {
1544                         return;
1545                 }
1546
1547                 $uid = User::getIdForURL($activity['object_object']);
1548                 if (empty($uid)) {
1549                         return;
1550                 }
1551
1552                 Contact\User::setIsBlocked($cid, $uid, false);
1553
1554                 Logger::info('Contact unblocked user', ['contact' => $cid, 'user' => $uid]);
1555                 Queue::remove($activity);
1556         }
1557
1558         /**
1559          * Accept a follow request
1560          *
1561          * @param array $activity
1562          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1563          * @throws \ImagickException
1564          */
1565         public static function acceptFollowUser(array $activity)
1566         {
1567                 $uid = User::getIdForURL($activity['object_actor']);
1568                 if (empty($uid)) {
1569                         return;
1570                 }
1571
1572                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1573                 if (empty($cid)) {
1574                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1575                         return;
1576                 }
1577
1578                 self::switchContact($cid);
1579
1580                 $fields = ['pending' => false];
1581
1582                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
1583                 if ($contact['rel'] == Contact::FOLLOWER) {
1584                         $fields['rel'] = Contact::FRIEND;
1585                 }
1586
1587                 $condition = ['id' => $cid];
1588                 Contact::update($fields, $condition);
1589                 Logger::info('Accept contact request', ['contact' => $cid, 'user' => $uid]);
1590                 Queue::remove($activity);
1591         }
1592
1593         /**
1594          * Reject a follow request
1595          *
1596          * @param array $activity
1597          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1598          * @throws \ImagickException
1599          */
1600         public static function rejectFollowUser(array $activity)
1601         {
1602                 $uid = User::getIdForURL($activity['object_actor']);
1603                 if (empty($uid)) {
1604                         return;
1605                 }
1606
1607                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1608                 if (empty($cid)) {
1609                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1610                         return;
1611                 }
1612
1613                 self::switchContact($cid);
1614
1615                 $contact = Contact::getById($cid, ['rel']);
1616                 if ($contact['rel'] == Contact::SHARING) {
1617                         Contact::remove($cid);
1618                         Logger::info('Rejected contact request - contact removed', ['contact' => $cid, 'user' => $uid]);
1619                 } elseif ($contact['rel'] == Contact::FRIEND) {
1620                         Contact::update(['rel' => Contact::FOLLOWER], ['id' => $cid]);
1621                 } else {
1622                         Logger::info('Rejected contact request', ['contact' => $cid, 'user' => $uid]);
1623                 }
1624                 Queue::remove($activity);
1625         }
1626
1627         /**
1628          * Undo activity like "like" or "dislike"
1629          *
1630          * @param array $activity
1631          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1632          * @throws \ImagickException
1633          */
1634         public static function undoActivity(array $activity)
1635         {
1636                 if (empty($activity['object_id'])) {
1637                         return;
1638                 }
1639
1640                 if (empty($activity['object_actor'])) {
1641                         return;
1642                 }
1643
1644                 $author_id = Contact::getIdForURL($activity['object_actor']);
1645                 if (empty($author_id)) {
1646                         return;
1647                 }
1648
1649                 Item::markForDeletion(['uri' => $activity['object_id'], 'author-id' => $author_id, 'gravity' => GRAVITY_ACTIVITY]);
1650                 Queue::remove($activity);
1651         }
1652
1653         /**
1654          * Activity to remove a follower
1655          *
1656          * @param array $activity
1657          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1658          * @throws \ImagickException
1659          */
1660         public static function undoFollowUser(array $activity)
1661         {
1662                 $uid = User::getIdForURL($activity['object_object']);
1663                 if (empty($uid)) {
1664                         return;
1665                 }
1666
1667                 $owner = User::getOwnerDataById($uid);
1668                 if (empty($owner)) {
1669                         return;
1670                 }
1671
1672                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1673                 if (empty($cid)) {
1674                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1675                         return;
1676                 }
1677
1678                 self::switchContact($cid);
1679
1680                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1681                 if (!DBA::isResult($contact)) {
1682                         return;
1683                 }
1684
1685                 Contact::removeFollower($contact);
1686                 Logger::info('Undo following request', ['contact' => $cid, 'user' => $uid]);
1687                 Queue::remove($activity);
1688         }
1689
1690         /**
1691          * Switches a contact to AP if needed
1692          *
1693          * @param integer $cid Contact ID
1694          * @return void
1695          * @throws \Exception
1696          */
1697         private static function switchContact(int $cid)
1698         {
1699                 $contact = DBA::selectFirst('contact', ['network', 'url'], ['id' => $cid]);
1700                 if (!DBA::isResult($contact) || in_array($contact['network'], [Protocol::ACTIVITYPUB, Protocol::DFRN]) || Contact::isLocal($contact['url'])) {
1701                         return;
1702                 }
1703
1704                 Logger::info('Change existing contact', ['cid' => $cid, 'previous' => $contact['network']]);
1705                 Contact::updateFromProbe($cid);
1706         }
1707
1708         /**
1709          * Collects implicit mentions like:
1710          * - the author of the parent item
1711          * - all the mentioned conversants in the parent item
1712          *
1713          * @param array $parent Item array with at least ['id', 'author-link', 'alias']
1714          * @return array
1715          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1716          */
1717         private static function getImplicitMentionList(array $parent): array
1718         {
1719                 $parent_terms = Tag::getByURIId($parent['uri-id'], [Tag::MENTION, Tag::IMPLICIT_MENTION, Tag::EXCLUSIVE_MENTION]);
1720
1721                 $parent_author = Contact::getByURL($parent['author-link'], false, ['url', 'nurl', 'alias']);
1722
1723                 $implicit_mentions = [];
1724                 if (empty($parent_author['url'])) {
1725                         Logger::notice('Author public contact unknown.', ['author-link' => $parent['author-link'], 'parent-id' => $parent['id']]);
1726                 } else {
1727                         $implicit_mentions[] = $parent_author['url'];
1728                         $implicit_mentions[] = $parent_author['nurl'];
1729                         $implicit_mentions[] = $parent_author['alias'];
1730                 }
1731
1732                 if (!empty($parent['alias'])) {
1733                         $implicit_mentions[] = $parent['alias'];
1734                 }
1735
1736                 foreach ($parent_terms as $term) {
1737                         $contact = Contact::getByURL($term['url'], false, ['url', 'nurl', 'alias']);
1738                         if (!empty($contact['url'])) {
1739                                 $implicit_mentions[] = $contact['url'];
1740                                 $implicit_mentions[] = $contact['nurl'];
1741                                 $implicit_mentions[] = $contact['alias'];
1742                         }
1743                 }
1744
1745                 return $implicit_mentions;
1746         }
1747
1748         /**
1749          * Strips from the body prepended implicit mentions
1750          *
1751          * @param string $body
1752          * @param array $parent
1753          * @return string
1754          */
1755         private static function removeImplicitMentionsFromBody(string $body, array $parent): string
1756         {
1757                 if (DI::config()->get('system', 'disable_implicit_mentions')) {
1758                         return $body;
1759                 }
1760
1761                 $potential_mentions = self::getImplicitMentionList($parent);
1762
1763                 $kept_mentions = [];
1764
1765                 // Extract one prepended mention at a time from the body
1766                 while(preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $body, $matches)) {
1767                         if (!in_array($matches[2], $potential_mentions)) {
1768                                 $kept_mentions[] = $matches[1];
1769                         }
1770
1771                         $body = $matches[3];
1772                 }
1773
1774                 // Re-appending the kept mentions to the body after extraction
1775                 $kept_mentions[] = $body;
1776
1777                 return implode('', $kept_mentions);
1778         }
1779
1780         /**
1781          * Adds links to string mentions
1782          *
1783          * @param string $body
1784          * @param array  $tags
1785          * @return string
1786          */
1787         protected static function addMentionLinks(string $body, array $tags): string
1788         {
1789                 // This prevents links to be added again to Pleroma-style mention links
1790                 $body = self::normalizeMentionLinks($body);
1791
1792                 $body = BBCode::performWithEscapedTags($body, ['url'], function ($body) use ($tags) {
1793                         foreach ($tags as $tag) {
1794                                 if (empty($tag['name']) || empty($tag['type']) || empty($tag['href']) || !in_array($tag['type'], ['Mention', 'Hashtag'])) {
1795                                         continue;
1796                                 }
1797
1798                                 $hash = substr($tag['name'], 0, 1);
1799                                 $name = substr($tag['name'], 1);
1800                                 if (!in_array($hash, Tag::TAG_CHARACTER)) {
1801                                         $hash = '';
1802                                         $name = $tag['name'];
1803                                 }
1804
1805                                 $body = str_replace($tag['name'], $hash . '[url=' . $tag['href'] . ']' . $name . '[/url]', $body);
1806                         }
1807
1808                         return $body;
1809                 });
1810
1811                 return $body;
1812         }
1813 }