]> git.mxchange.org Git - friendica.git/blob - src/Protocol/ActivityPub/Processor.php
Merge pull request #8978 from annando/contact-update
[friendica.git] / src / Protocol / ActivityPub / Processor.php
1 <?php
2 /**
3  * @copyright Copyright (C) 2020, Friendica
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\PageInfo;
25 use Friendica\Content\Text\BBCode;
26 use Friendica\Content\Text\HTML;
27 use Friendica\Core\Logger;
28 use Friendica\Core\Protocol;
29 use Friendica\Database\DBA;
30 use Friendica\DI;
31 use Friendica\Model\APContact;
32 use Friendica\Model\Contact;
33 use Friendica\Model\Conversation;
34 use Friendica\Model\Event;
35 use Friendica\Model\Item;
36 use Friendica\Model\ItemURI;
37 use Friendica\Model\Mail;
38 use Friendica\Model\Tag;
39 use Friendica\Model\User;
40 use Friendica\Protocol\Activity;
41 use Friendica\Protocol\ActivityPub;
42 use Friendica\Util\DateTimeFormat;
43 use Friendica\Util\JsonLD;
44 use Friendica\Util\Strings;
45
46 /**
47  * ActivityPub Processor Protocol class
48  */
49 class Processor
50 {
51         /**
52          * Converts mentions from Pleroma into the Friendica format
53          *
54          * @param string $body
55          *
56          * @return string converted body
57          */
58         private static function convertMentions($body)
59         {
60                 $URLSearchString = "^\[\]";
61                 $body = preg_replace("/\[url\=([$URLSearchString]*)\]([#@!])(.*?)\[\/url\]/ism", '$2[url=$1]$3[/url]', $body);
62
63                 return $body;
64         }
65
66         /**
67          * Replaces emojis in the body
68          *
69          * @param array $emojis
70          * @param string $body
71          *
72          * @return string with replaced emojis
73          */
74         private static function replaceEmojis($body, array $emojis)
75         {
76                 foreach ($emojis as $emoji) {
77                         $replace = '[class=emoji mastodon][img=' . $emoji['href'] . ']' . $emoji['name'] . '[/img][/class]';
78                         $body = str_replace($emoji['name'], $replace, $body);
79                 }
80                 return $body;
81         }
82
83         /**
84          * Add attachment data to the item array
85          *
86          * @param array   $activity
87          * @param array   $item
88          *
89          * @return array array
90          */
91         private static function constructAttachList($activity, $item)
92         {
93                 if (empty($activity['attachments'])) {
94                         return $item;
95                 }
96
97                 foreach ($activity['attachments'] as $attach) {
98                         switch ($attach['type']) {
99                                 case 'link':
100                                         $data = [
101                                                 'url'      => $attach['url'],
102                                                 'type'     => $attach['type'],
103                                                 'title'    => $attach['title'] ?? '',
104                                                 'text'     => $attach['desc']  ?? '',
105                                                 'image'    => $attach['image'] ?? '',
106                                                 'images'   => [],
107                                                 'keywords' => [],
108                                         ];
109                                         $item['body'] = PageInfo::appendDataToBody($item['body'], $data);
110                                         break;
111                                 default:
112                                         $filetype = strtolower(substr($attach['mediaType'], 0, strpos($attach['mediaType'], '/')));
113                                         if ($filetype == 'image') {
114                                                 if (!empty($activity['source']) && strpos($activity['source'], $attach['url'])) {
115                                                         continue 2;
116                                                 }
117
118                                                 $item['body'] .= "\n";
119
120                                                 // image is the preview/thumbnail URL
121                                                 if (!empty($attach['image'])) {
122                                                         $item['body'] .= '[url=' . $attach['url'] . ']';
123                                                         $attach['url'] = $attach['image'];
124                                                 }
125
126                                                 if (empty($attach['name'])) {
127                                                         $item['body'] .= '[img]' . $attach['url'] . '[/img]';
128                                                 } else {
129                                                         $item['body'] .= '[img=' . $attach['url'] . ']' . $attach['name'] . '[/img]';
130                                                 }
131
132                                                 if (!empty($attach['image'])) {
133                                                         $item['body'] .= '[/url]';
134                                                 }
135                                         } elseif ($filetype == 'audio') {
136                                                 if (!empty($activity['source']) && strpos($activity['source'], $attach['url'])) {
137                                                         continue 2;
138                                                 }
139
140                                                 $item['body'] .= "\n[audio]" . $attach['url'] . '[/audio]';
141                                         } elseif ($filetype == 'video') {
142                                                 if (!empty($activity['source']) && strpos($activity['source'], $attach['url'])) {
143                                                         continue 2;
144                                                 }
145
146                                                 $item['body'] .= "\n[video]" . $attach['url'] . '[/video]';
147                                         } else {
148                                                 if (!empty($item["attach"])) {
149                                                         $item["attach"] .= ',';
150                                                 } else {
151                                                         $item["attach"] = '';
152                                                 }
153
154                                                 $item["attach"] .= '[attach]href="' . $attach['url'] . '" length="' . ($attach['length'] ?? '0') . '" type="' . $attach['mediaType'] . '" title="' . ($attach['name'] ?? '') . '"[/attach]';
155                                         }
156                         }
157                 }
158
159                 return $item;
160         }
161
162         /**
163          * Updates a message
164          *
165          * @param array $activity Activity array
166          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
167          */
168         public static function updateItem($activity)
169         {
170                 $item = Item::selectFirst(['uri', 'uri-id', 'thr-parent', 'gravity'], ['uri' => $activity['id']]);
171                 if (!DBA::isResult($item)) {
172                         Logger::warning('No existing item, item will be created', ['uri' => $activity['id']]);
173                         $item = self::createItem($activity);
174                         self::postItem($activity, $item);
175                         return;
176                 }
177
178                 $item['changed'] = DateTimeFormat::utcNow();
179                 $item['edited'] = DateTimeFormat::utc($activity['updated']);
180
181                 $item = self::processContent($activity, $item);
182                 if (empty($item)) {
183                         return;
184                 }
185
186                 Item::update($item, ['uri' => $activity['id']]);
187         }
188
189         /**
190          * Prepares data for a message
191          *
192          * @param array $activity Activity array
193          * @return array Internal item
194          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
195          * @throws \ImagickException
196          */
197         public static function createItem($activity)
198         {
199                 $item = [];
200                 $item['verb'] = Activity::POST;
201                 $item['thr-parent'] = $activity['reply-to-id'];
202
203                 if ($activity['reply-to-id'] == $activity['id']) {
204                         $item['gravity'] = GRAVITY_PARENT;
205                         $item['object-type'] = Activity\ObjectType::NOTE;
206                 } else {
207                         $item['gravity'] = GRAVITY_COMMENT;
208                         $item['object-type'] = Activity\ObjectType::COMMENT;
209
210                         // Ensure that the comment reaches all receivers of the referring post
211                         $activity['receiver'] = self::addReceivers($activity);
212                 }
213
214                 if (empty($activity['directmessage']) && ($activity['id'] != $activity['reply-to-id']) && !Item::exists(['uri' => $activity['reply-to-id']])) {
215                         Logger::notice('Parent not found. Try to refetch it.', ['parent' => $activity['reply-to-id']]);
216                         self::fetchMissingActivity($activity['reply-to-id'], $activity);
217                 }
218
219                 $item['diaspora_signed_text'] = $activity['diaspora:comment'] ?? '';
220
221                 /// @todo What to do with $activity['context']?
222                 if (empty($activity['directmessage']) && ($item['gravity'] != GRAVITY_PARENT) && !Item::exists(['uri' => $item['thr-parent']])) {
223                         Logger::info('Parent not found, message will be discarded.', ['thr-parent' => $item['thr-parent']]);
224                         return [];
225                 }
226
227                 $item['network'] = Protocol::ACTIVITYPUB;
228                 $item['author-link'] = $activity['author'];
229                 $item['author-id'] = Contact::getIdForURL($activity['author'], 0, false);
230                 $item['owner-link'] = $activity['actor'];
231                 $item['owner-id'] = Contact::getIdForURL($activity['actor'], 0, false);
232
233                 if (in_array(0, $activity['receiver']) && !empty($activity['unlisted'])) {
234                         $item['private'] = Item::UNLISTED;
235                 } elseif (in_array(0, $activity['receiver'])) {
236                         $item['private'] = Item::PUBLIC;
237                 } else {
238                         $item['private'] = Item::PRIVATE;
239                 }
240
241                 if (!empty($activity['raw'])) {
242                         $item['source'] = $activity['raw'];
243                         $item['protocol'] = Conversation::PARCEL_ACTIVITYPUB;
244                         $item['conversation-href'] = $activity['context'] ?? '';
245                         $item['conversation-uri'] = $activity['conversation'] ?? '';
246
247                         if (isset($activity['push'])) {
248                                 $item['direction'] = $activity['push'] ? Conversation::PUSH : Conversation::PULL;
249                         }
250                 }
251
252                 $item['isForum'] = false;
253
254                 if (!empty($activity['thread-completion'])) {
255                         // Store the original actor in the "causer" fields to enable the check for ignored or blocked contacts
256                         $item['causer-link'] = $item['owner-link'];
257                         $item['causer-id'] = $item['owner-id'];
258
259                         Logger::info('Ignoring actor because of thread completion.', ['actor' => $item['owner-link']]);
260                         $item['owner-link'] = $item['author-link'];
261                         $item['owner-id'] = $item['author-id'];
262                 } else {
263                         $actor = APContact::getByURL($item['owner-link'], false);
264                         $item['isForum'] = ($actor['type'] == 'Group');
265                 }
266
267                 $item['uri'] = $activity['id'];
268
269                 $item['created'] = DateTimeFormat::utc($activity['published']);
270                 $item['edited'] = DateTimeFormat::utc($activity['updated']);
271                 $guid = $activity['sc:identifier'] ?: self::getGUIDByURL($item['uri']);
272                 $item['guid'] = $activity['diaspora:guid'] ?: $guid;
273
274                 $item['uri-id'] = ItemURI::insert(['uri' => $item['uri'], 'guid' => $item['guid']]);
275
276                 $item = self::processContent($activity, $item);
277                 if (empty($item)) {
278                         return [];
279                 }
280
281                 $item['plink'] = $activity['alternate-url'] ?? $item['uri'];
282
283                 $item = self::constructAttachList($activity, $item);
284
285                 return $item;
286         }
287
288         /**
289          * Delete items
290          *
291          * @param array $activity
292          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
293          * @throws \ImagickException
294          */
295         public static function deleteItem($activity)
296         {
297                 $owner = Contact::getIdForURL($activity['actor']);
298
299                 Logger::info('Deleting item', ['object' => $activity['object_id'], 'owner'  => $owner]);
300                 Item::markForDeletion(['uri' => $activity['object_id'], 'owner-id' => $owner]);
301         }
302
303         /**
304          * Prepare the item array for an activity
305          *
306          * @param array $activity Activity array
307          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
308          * @throws \ImagickException
309          */
310         public static function addTag($activity)
311         {
312                 if (empty($activity['object_content']) || empty($activity['object_id'])) {
313                         return;
314                 }
315
316                 foreach ($activity['receiver'] as $receiver) {
317                         $item = Item::selectFirst(['id', 'uri-id', 'tag', 'origin', 'author-link'], ['uri' => $activity['target_id'], 'uid' => $receiver]);
318                         if (!DBA::isResult($item)) {
319                                 // We don't fetch missing content for this purpose
320                                 continue;
321                         }
322
323                         if (($item['author-link'] != $activity['actor']) && !$item['origin']) {
324                                 Logger::info('Not origin, not from the author, skipping update', ['id' => $item['id'], 'author' => $item['author-link'], 'actor' => $activity['actor']]);
325                                 continue;
326                         }
327
328                         Tag::store($item['uri-id'], Tag::HASHTAG, $activity['object_content'], $activity['object_id']);
329                         Logger::info('Tagged item', ['id' => $item['id'], 'tag' => $activity['object_content'], 'uri' => $activity['target_id'], 'actor' => $activity['actor']]);
330                 }
331         }
332
333         /**
334          * Add users to the receiver list of the given public activity.
335          * This is used to ensure that the activity will be stored in every thread.
336          *
337          * @param array $activity Activity array
338          * @return array Modified receiver list
339          */
340         private static function addReceivers(array $activity)
341         {
342                 if (!in_array(0, $activity['receiver'])) {
343                         // Private activities will not be modified
344                         return $activity['receiver'];
345                 }
346
347                 // Add all owners of the referring item to the receivers
348                 $original = $receivers = $activity['receiver'];
349                 $items = Item::select(['uid'], ['uri' => $activity['object_id']]);
350                 while ($item = DBA::fetch($items)) {
351                         $receivers['uid:' . $item['uid']] = $item['uid'];
352                 }
353                 DBA::close($items);
354
355                 if (count($original) != count($receivers)) {
356                         Logger::info('Improved data', ['id' => $activity['id'], 'object' => $activity['object_id'], 'original' => $original, 'improved' => $receivers]);
357                 }
358
359                 return $receivers;
360         }
361
362         /**
363          * Prepare the item array for an activity
364          *
365          * @param array  $activity Activity array
366          * @param string $verb     Activity verb
367          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
368          * @throws \ImagickException
369          */
370         public static function createActivity($activity, $verb)
371         {
372                 $item = self::createItem($activity);
373                 $item['verb'] = $verb;
374                 $item['thr-parent'] = $activity['object_id'];
375                 $item['gravity'] = GRAVITY_ACTIVITY;
376                 $item['object-type'] = Activity\ObjectType::NOTE;
377
378                 $item['diaspora_signed_text'] = $activity['diaspora:like'] ?? '';
379
380                 $activity['receiver'] = self::addReceivers($activity);
381
382                 self::postItem($activity, $item);
383         }
384
385         /**
386          * Create an event
387          *
388          * @param array $activity Activity array
389          * @param array $item
390          * @throws \Exception
391          */
392         public static function createEvent($activity, $item)
393         {
394                 $event['summary']  = HTML::toBBCode($activity['name']);
395                 $event['desc']     = HTML::toBBCode($activity['content']);
396                 $event['start']    = $activity['start-time'];
397                 $event['finish']   = $activity['end-time'];
398                 $event['nofinish'] = empty($event['finish']);
399                 $event['location'] = $activity['location'];
400                 $event['adjust']   = true;
401                 $event['cid']      = $item['contact-id'];
402                 $event['uid']      = $item['uid'];
403                 $event['uri']      = $item['uri'];
404                 $event['edited']   = $item['edited'];
405                 $event['private']  = $item['private'];
406                 $event['guid']     = $item['guid'];
407                 $event['plink']    = $item['plink'];
408
409                 $condition = ['uri' => $item['uri'], 'uid' => $item['uid']];
410                 $ev = DBA::selectFirst('event', ['id'], $condition);
411                 if (DBA::isResult($ev)) {
412                         $event['id'] = $ev['id'];
413                 }
414
415                 $event_id = Event::store($event);
416                 Logger::info('Event was stored', ['id' => $event_id]);
417         }
418
419         /**
420          * Process the content
421          *
422          * @param array $activity Activity array
423          * @param array $item
424          * @return array|bool Returns the item array or false if there was an unexpected occurrence
425          * @throws \Exception
426          */
427         private static function processContent($activity, $item)
428         {
429                 $item['title'] = HTML::toBBCode($activity['name']);
430
431                 if (!empty($activity['source'])) {
432                         $item['body'] = $activity['source'];
433                 } else {
434                         $content = HTML::toBBCode($activity['content']);
435
436                         if (!empty($activity['emojis'])) {
437                                 $content = self::replaceEmojis($content, $activity['emojis']);
438                         }
439
440                         $content = self::convertMentions($content);
441
442                         if (empty($activity['directmessage']) && ($item['thr-parent'] != $item['uri']) && ($item['gravity'] == GRAVITY_COMMENT)) {
443                                 $item_private = !in_array(0, $activity['item_receiver']);
444                                 $parent = Item::selectFirst(['id', 'uri-id', 'private', 'author-link', 'alias'], ['uri' => $item['thr-parent']]);
445                                 if (!DBA::isResult($parent)) {
446                                         Logger::warning('Unknown parent item.', ['uri' => $item['thr-parent']]);
447                                         return false;
448                                 }
449                                 if ($item_private && ($parent['private'] != Item::PRIVATE)) {
450                                         Logger::warning('Item is private but the parent is not. Dropping.', ['item-uri' => $item['uri'], 'thr-parent' => $item['thr-parent']]);
451                                         return false;
452                                 }
453
454                                 $content = self::removeImplicitMentionsFromBody($content, $parent);
455                         }
456                         $item['content-warning'] = HTML::toBBCode($activity['summary']);
457                         $item['body'] = $content;
458                 }
459
460                 self::storeFromBody($item);
461                 self::storeTags($item['uri-id'], $activity['tags']);
462
463                 $item['location'] = $activity['location'];
464
465                 if (!empty($activity['latitude']) && !empty($activity['longitude'])) {
466                         $item['coord'] = $activity['latitude'] . ' ' . $activity['longitude'];
467                 }
468
469                 $item['app'] = $activity['generator'];
470
471                 return $item;
472         }
473
474         /**
475          * Store hashtags and mentions
476          *
477          * @param array $item
478          */
479         private static function storeFromBody(array $item)
480         {
481                 // Make sure to delete all existing tags (can happen when called via the update functionality)
482                 DBA::delete('post-tag', ['uri-id' => $item['uri-id']]);
483
484                 Tag::storeFromBody($item['uri-id'], $item['body'], '@!');
485         }
486
487         /**
488          * Generate a GUID out of an URL
489          *
490          * @param string $url message URL
491          * @return string with GUID
492          */
493         private static function getGUIDByURL(string $url)
494         {
495                 $parsed = parse_url($url);
496
497                 $host_hash = hash('crc32', $parsed['host']);
498
499                 unset($parsed["scheme"]);
500                 unset($parsed["host"]);
501
502                 $path = implode("/", $parsed);
503
504                 return $host_hash . '-'. hash('fnv164', $path) . '-'. hash('joaat', $path);
505         }
506
507         /**
508          * Creates an item post
509          *
510          * @param array $activity Activity data
511          * @param array $item     item array
512          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
513          * @throws \ImagickException
514          */
515         public static function postItem(array $activity, array $item)
516         {
517                 if (empty($item)) {
518                         return;
519                 }
520
521                 $stored = false;
522
523                 foreach ($activity['receiver'] as $receiver) {
524                         if ($receiver == -1) {
525                                 continue;
526                         }
527
528                         $item['uid'] = $receiver;
529
530                         if ($item['isForum'] ?? false) {
531                                 $item['contact-id'] = Contact::getIdForURL($activity['actor'], $receiver, false);
532                         } else {
533                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver, false);
534                         }
535
536                         if (($receiver != 0) && empty($item['contact-id'])) {
537                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], 0, false);
538                         }
539
540                         if (!empty($activity['directmessage'])) {
541                                 self::postMail($activity, $item);
542                                 continue;
543                         }
544
545                         if (DI::pConfig()->get($receiver, 'system', 'accept_only_sharer', false) && ($receiver != 0) && ($item['gravity'] == GRAVITY_PARENT)) {
546                                 $skip = !Contact::isSharingByURL($activity['author'], $receiver);
547
548                                 if ($skip && (($activity['type'] == 'as:Announce') || ($item['isForum'] ?? false))) {
549                                         $skip = !Contact::isSharingByURL($activity['actor'], $receiver);
550                                 }
551
552                                 if ($skip) {
553                                         Logger::info('Skipping post', ['uid' => $receiver, 'url' => $item['uri']]);
554                                         continue;
555                                 }
556
557                                 Logger::info('Accepting post', ['uid' => $receiver, 'url' => $item['uri']]);
558                         }
559
560                         if (($item['gravity'] != GRAVITY_ACTIVITY) && ($activity['object_type'] == 'as:Event')) {
561                                 self::createEvent($activity, $item);
562                         }
563
564                         $item_id = Item::insert($item);
565                         if ($item_id) {
566                                 Logger::info('Item insertion successful', ['user' => $item['uid'], 'item_id' => $item_id]);
567                         } else {
568                                 Logger::notice('Item insertion aborted', ['user' => $item['uid']]);
569                         }
570
571                         if ($item['uid'] == 0) {
572                                 $stored = $item_id;
573                         }
574                 }
575
576                 // Store send a follow request for every reshare - but only when the item had been stored
577                 if ($stored && ($item['private'] != Item::PRIVATE) && ($item['gravity'] == GRAVITY_PARENT) && ($item['author-link'] != $item['owner-link'])) {
578                         $author = APContact::getByURL($item['owner-link'], false);
579                         // We send automatic follow requests for reshared messages. (We don't need though for forum posts)
580                         if ($author['type'] != 'Group') {
581                                 Logger::info('Send follow request', ['uri' => $item['uri'], 'stored' => $stored, 'to' => $item['author-link']]);
582                                 ActivityPub\Transmitter::sendFollowObject($item['uri'], $item['author-link']);
583                         }
584                 }
585         }
586
587         /**
588          * Store tags and mentions into the tag table
589          *
590          * @param integer $uriid
591          * @param array $tags
592          */
593         private static function storeTags(int $uriid, array $tags = null)
594         {
595                 foreach ($tags as $tag) {
596                         if (empty($tag['name']) || empty($tag['type']) || !in_array($tag['type'], ['Mention', 'Hashtag'])) {
597                                 continue;
598                         }
599
600                         $hash = substr($tag['name'], 0, 1);
601
602                         if ($tag['type'] == 'Mention') {
603                                 if (in_array($hash, [Tag::TAG_CHARACTER[Tag::MENTION],
604                                         Tag::TAG_CHARACTER[Tag::EXCLUSIVE_MENTION],
605                                         Tag::TAG_CHARACTER[Tag::IMPLICIT_MENTION]])) {
606                                         $tag['name'] = substr($tag['name'], 1);
607                                 }
608                                 $type = Tag::IMPLICIT_MENTION;
609
610                                 if (!empty($tag['href'])) {
611                                         $apcontact = APContact::getByURL($tag['href']);
612                                         if (!empty($apcontact['name']) || !empty($apcontact['nick'])) {
613                                                 $tag['name'] = $apcontact['name'] ?: $apcontact['nick'];
614                                         }
615                                 }
616                         } elseif ($tag['type'] == 'Hashtag') {
617                                 if ($hash == Tag::TAG_CHARACTER[Tag::HASHTAG]) {
618                                         $tag['name'] = substr($tag['name'], 1);
619                                 }
620                                 $type = Tag::HASHTAG;
621                         }
622
623                         if (empty($tag['name'])) {
624                                 continue;
625                         }
626
627                         Tag::store($uriid, $type, $tag['name'], $tag['href']);
628                 }
629         }
630
631         /**
632          * Creates an mail post
633          *
634          * @param array $activity Activity data
635          * @param array $item     item array
636          * @return int|bool New mail table row id or false on error
637          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
638          */
639         private static function postMail($activity, $item)
640         {
641                 if (($item['gravity'] != GRAVITY_PARENT) && !DBA::exists('mail', ['uri' => $item['thr-parent'], 'uid' => $item['uid']])) {
642                         Logger::info('Parent not found, mail will be discarded.', ['uid' => $item['uid'], 'uri' => $item['thr-parent']]);
643                         return false;
644                 }
645
646                 Logger::info('Direct Message', $item);
647
648                 $msg = [];
649                 $msg['uid'] = $item['uid'];
650
651                 $msg['contact-id'] = $item['contact-id'];
652
653                 $contact = Contact::getById($item['contact-id'], ['name', 'url', 'photo']);
654                 $msg['from-name'] = $contact['name'];
655                 $msg['from-url'] = $contact['url'];
656                 $msg['from-photo'] = $contact['photo'];
657
658                 $msg['uri'] = $item['uri'];
659                 $msg['created'] = $item['created'];
660
661                 $parent = DBA::selectFirst('mail', ['parent-uri', 'title'], ['uri' => $item['thr-parent']]);
662                 if (DBA::isResult($parent)) {
663                         $msg['parent-uri'] = $parent['parent-uri'];
664                         $msg['title'] = $parent['title'];
665                 } else {
666                         $msg['parent-uri'] = $item['thr-parent'];
667
668                         if (!empty($item['title'])) {
669                                 $msg['title'] = $item['title'];
670                         } elseif (!empty($item['content-warning'])) {
671                                 $msg['title'] = $item['content-warning'];
672                         } else {
673                                 // Trying to generate a title out of the body
674                                 $title = $item['body'];
675
676                                 while (preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $title, $matches)) {
677                                         $title = $matches[3];
678                                 }
679
680                                 $title = trim(HTML::toPlaintext(BBCode::convert($title, false, BBCode::API, true), 0));
681
682                                 if (strlen($title) > 20) {
683                                         $title = substr($title, 0, 20) . '...';
684                                 }
685
686                                 $msg['title'] = $title;
687                         }
688                 }
689                 $msg['body'] = $item['body'];
690
691                 return Mail::insert($msg);
692         }
693
694         /**
695          * Fetches missing posts
696          *
697          * @param string $url message URL
698          * @param array $child activity array with the child of this message
699          * @return string fetched message URL
700          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
701          */
702         public static function fetchMissingActivity(string $url, array $child = [])
703         {
704                 if (!empty($child['receiver'])) {
705                         $uid = ActivityPub\Receiver::getFirstUserFromReceivers($child['receiver']);
706                 } else {
707                         $uid = 0;
708                 }
709
710                 $object = ActivityPub::fetchContent($url, $uid);
711                 if (empty($object)) {
712                         Logger::log('Activity ' . $url . ' was not fetchable, aborting.');
713                         return '';
714                 }
715
716                 if (empty($object['id'])) {
717                         Logger::log('Activity ' . $url . ' has got not id, aborting. ' . json_encode($object));
718                         return '';
719                 }
720
721                 if (!empty($child['author'])) {
722                         $actor = $child['author'];
723                 } elseif (!empty($object['actor'])) {
724                         $actor = $object['actor'];
725                 } elseif (!empty($object['attributedTo'])) {
726                         $actor = $object['attributedTo'];
727                 } else {
728                         // Shouldn't happen
729                         $actor = '';
730                 }
731
732                 if (!empty($object['published'])) {
733                         $published = $object['published'];
734                 } elseif (!empty($child['published'])) {
735                         $published = $child['published'];
736                 } else {
737                         $published = DateTimeFormat::utcNow();
738                 }
739
740                 $activity = [];
741                 $activity['@context'] = $object['@context'];
742                 unset($object['@context']);
743                 $activity['id'] = $object['id'];
744                 $activity['to'] = $object['to'] ?? [];
745                 $activity['cc'] = $object['cc'] ?? [];
746                 $activity['actor'] = $actor;
747                 $activity['object'] = $object;
748                 $activity['published'] = $published;
749                 $activity['type'] = 'Create';
750
751                 $ldactivity = JsonLD::compact($activity);
752
753                 $ldactivity['thread-completion'] = true;
754
755                 ActivityPub\Receiver::processActivity($ldactivity, json_encode($activity));
756
757                 Logger::notice('Activity had been fetched and processed.', ['url' => $url, 'object' => $activity['id']]);
758
759                 return $activity['id'];
760         }
761
762         /**
763          * perform a "follow" request
764          *
765          * @param array $activity
766          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
767          * @throws \ImagickException
768          */
769         public static function followUser($activity)
770         {
771                 $uid = User::getIdForURL($activity['object_id']);
772                 if (empty($uid)) {
773                         return;
774                 }
775
776                 $owner = User::getOwnerDataById($uid);
777
778                 $cid = Contact::getIdForURL($activity['actor'], $uid);
779                 if (!empty($cid)) {
780                         self::switchContact($cid);
781                         DBA::update('contact', ['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
782                         $contact = DBA::selectFirst('contact', [], ['id' => $cid, 'network' => Protocol::NATIVE_SUPPORT]);
783                 } else {
784                         $contact = [];
785                 }
786
787                 $item = ['author-id' => Contact::getIdForURL($activity['actor']),
788                         'author-link' => $activity['actor']];
789
790                 $note = Strings::escapeTags(trim($activity['content'] ?? ''));
791
792                 // Ensure that the contact has got the right network type
793                 self::switchContact($item['author-id']);
794
795                 $result = Contact::addRelationship($owner, $contact, $item, false, $note);
796                 if ($result === true) {
797                         ActivityPub\Transmitter::sendContactAccept($item['author-link'], $activity['id'], $owner['uid']);
798                 }
799
800                 $cid = Contact::getIdForURL($activity['actor'], $uid);
801                 if (empty($cid)) {
802                         return;
803                 }
804
805                 if (empty($contact)) {
806                         DBA::update('contact', ['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
807                 }
808
809                 Logger::log('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
810         }
811
812         /**
813          * Update the given profile
814          *
815          * @param array $activity
816          * @throws \Exception
817          */
818         public static function updatePerson($activity)
819         {
820                 if (empty($activity['object_id'])) {
821                         return;
822                 }
823
824                 Logger::info('Updating profile', ['object' => $activity['object_id']]);
825                 Contact::updateFromProbeByURL($activity['object_id'], true);
826         }
827
828         /**
829          * Delete the given profile
830          *
831          * @param array $activity
832          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
833          */
834         public static function deletePerson($activity)
835         {
836                 if (empty($activity['object_id']) || empty($activity['actor'])) {
837                         Logger::info('Empty object id or actor.');
838                         return;
839                 }
840
841                 if ($activity['object_id'] != $activity['actor']) {
842                         Logger::info('Object id does not match actor.');
843                         return;
844                 }
845
846                 $contacts = DBA::select('contact', ['id'], ['nurl' => Strings::normaliseLink($activity['object_id'])]);
847                 while ($contact = DBA::fetch($contacts)) {
848                         Contact::remove($contact['id']);
849                 }
850                 DBA::close($contacts);
851
852                 Logger::info('Deleted contact', ['object' => $activity['object_id']]);
853         }
854
855         /**
856          * Accept a follow request
857          *
858          * @param array $activity
859          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
860          * @throws \ImagickException
861          */
862         public static function acceptFollowUser($activity)
863         {
864                 $uid = User::getIdForURL($activity['object_actor']);
865                 if (empty($uid)) {
866                         return;
867                 }
868
869                 $cid = Contact::getIdForURL($activity['actor'], $uid);
870                 if (empty($cid)) {
871                         Logger::info('No contact found', ['actor' => $activity['actor']]);
872                         return;
873                 }
874
875                 self::switchContact($cid);
876
877                 $fields = ['pending' => false];
878
879                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
880                 if ($contact['rel'] == Contact::FOLLOWER) {
881                         $fields['rel'] = Contact::FRIEND;
882                 }
883
884                 $condition = ['id' => $cid];
885                 DBA::update('contact', $fields, $condition);
886                 Logger::info('Accept contact request', ['contact' => $cid, 'user' => $uid]);
887         }
888
889         /**
890          * Reject a follow request
891          *
892          * @param array $activity
893          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
894          * @throws \ImagickException
895          */
896         public static function rejectFollowUser($activity)
897         {
898                 $uid = User::getIdForURL($activity['object_actor']);
899                 if (empty($uid)) {
900                         return;
901                 }
902
903                 $cid = Contact::getIdForURL($activity['actor'], $uid);
904                 if (empty($cid)) {
905                         Logger::info('No contact found', ['actor' => $activity['actor']]);
906                         return;
907                 }
908
909                 self::switchContact($cid);
910
911                 if (DBA::exists('contact', ['id' => $cid, 'rel' => Contact::SHARING])) {
912                         Contact::remove($cid);
913                         Logger::info('Rejected contact request - contact removed', ['contact' => $cid, 'user' => $uid]);
914                 } else {
915                         Logger::info('Rejected contact request', ['contact' => $cid, 'user' => $uid]);
916                 }
917         }
918
919         /**
920          * Undo activity like "like" or "dislike"
921          *
922          * @param array $activity
923          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
924          * @throws \ImagickException
925          */
926         public static function undoActivity($activity)
927         {
928                 if (empty($activity['object_id'])) {
929                         return;
930                 }
931
932                 if (empty($activity['object_actor'])) {
933                         return;
934                 }
935
936                 $author_id = Contact::getIdForURL($activity['object_actor']);
937                 if (empty($author_id)) {
938                         return;
939                 }
940
941                 Item::markForDeletion(['uri' => $activity['object_id'], 'author-id' => $author_id, 'gravity' => GRAVITY_ACTIVITY]);
942         }
943
944         /**
945          * Activity to remove a follower
946          *
947          * @param array $activity
948          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
949          * @throws \ImagickException
950          */
951         public static function undoFollowUser($activity)
952         {
953                 $uid = User::getIdForURL($activity['object_object']);
954                 if (empty($uid)) {
955                         return;
956                 }
957
958                 $owner = User::getOwnerDataById($uid);
959
960                 $cid = Contact::getIdForURL($activity['actor'], $uid);
961                 if (empty($cid)) {
962                         Logger::info('No contact found', ['actor' => $activity['actor']]);
963                         return;
964                 }
965
966                 self::switchContact($cid);
967
968                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
969                 if (!DBA::isResult($contact)) {
970                         return;
971                 }
972
973                 Contact::removeFollower($owner, $contact);
974                 Logger::info('Undo following request', ['contact' => $cid, 'user' => $uid]);
975         }
976
977         /**
978          * Switches a contact to AP if needed
979          *
980          * @param integer $cid Contact ID
981          * @throws \Exception
982          */
983         private static function switchContact($cid)
984         {
985                 $contact = DBA::selectFirst('contact', ['network', 'url'], ['id' => $cid]);
986                 if (!DBA::isResult($contact) || in_array($contact['network'], [Protocol::ACTIVITYPUB, Protocol::DFRN]) || Contact::isLocal($contact['url'])) {
987                         return;
988                 }
989
990                 Logger::info('Change existing contact', ['cid' => $cid, 'previous' => $contact['network']]);
991                 Contact::updateFromProbe($cid);
992         }
993
994         /**
995          * Collects implicit mentions like:
996          * - the author of the parent item
997          * - all the mentioned conversants in the parent item
998          *
999          * @param array $parent Item array with at least ['id', 'author-link', 'alias']
1000          * @return array
1001          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1002          */
1003         private static function getImplicitMentionList(array $parent)
1004         {
1005                 $parent_terms = Tag::getByURIId($parent['uri-id'], [Tag::MENTION, Tag::IMPLICIT_MENTION, Tag::EXCLUSIVE_MENTION]);
1006
1007                 $parent_author = Contact::getByURL($parent['author-link'], false, ['url', 'nurl', 'alias']);
1008
1009                 $implicit_mentions = [];
1010                 if (empty($parent_author['url'])) {
1011                         Logger::notice('Author public contact unknown.', ['author-link' => $parent['author-link'], 'item-id' => $parent['id']]);
1012                 } else {
1013                         $implicit_mentions[] = $parent_author['url'];
1014                         $implicit_mentions[] = $parent_author['nurl'];
1015                         $implicit_mentions[] = $parent_author['alias'];
1016                 }
1017
1018                 if (!empty($parent['alias'])) {
1019                         $implicit_mentions[] = $parent['alias'];
1020                 }
1021
1022                 foreach ($parent_terms as $term) {
1023                         $contact = Contact::getByURL($term['url'], false, ['url', 'nurl', 'alias']);
1024                         if (!empty($contact['url'])) {
1025                                 $implicit_mentions[] = $contact['url'];
1026                                 $implicit_mentions[] = $contact['nurl'];
1027                                 $implicit_mentions[] = $contact['alias'];
1028                         }
1029                 }
1030
1031                 return $implicit_mentions;
1032         }
1033
1034         /**
1035          * Strips from the body prepended implicit mentions
1036          *
1037          * @param string $body
1038          * @param array $parent
1039          * @return string
1040          */
1041         private static function removeImplicitMentionsFromBody(string $body, array $parent)
1042         {
1043                 if (DI::config()->get('system', 'disable_implicit_mentions')) {
1044                         return $body;
1045                 }
1046
1047                 $potential_mentions = self::getImplicitMentionList($parent);
1048
1049                 $kept_mentions = [];
1050
1051                 // Extract one prepended mention at a time from the body
1052                 while(preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $body, $matches)) {
1053                         if (!in_array($matches[2], $potential_mentions)) {
1054                                 $kept_mentions[] = $matches[1];
1055                         }
1056
1057                         $body = $matches[3];
1058                 }
1059
1060                 // Re-appending the kept mentions to the body after extraction
1061                 $kept_mentions[] = $body;
1062
1063                 return implode('', $kept_mentions);
1064         }
1065 }