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         const CACHEKEY_JUST_FETCHED   = 'processor:isJustFetched:';
  62         /**
  63          * Extracts the tag character (#, @, !) from mention links
  64          *
  65          * @param string $body
  66          * @return string
  67          */
  68         protected static function normalizeMentionLinks(string $body): string
  69         {
  70                 return preg_replace('%\[url=([^\[\]]*)]([#@!])(.*?)\[/url]%ism', '$2[url=$1]$3[/url]', $body);
  71         }
  72
  73         /**
  74          * Convert the language array into a language JSON
  75          *
  76          * @param array $languages
  77          * @return string language JSON
  78          */
  79         private static function processLanguages(array $languages): string
  80         {
  81                 $codes = array_keys($languages);
  82                 $lang = [];
  83                 foreach ($codes as $code) {
  84                         $lang[$code] = 1;
  85                 }
  86
  87                 if (empty($lang)) {
  88                         return '';
  89                 }
  90
  91                 return json_encode($lang);
  92         }
  93         /**
  94          * Replaces emojis in the body
  95          *
  96          * @param int $uri_id
  97          * @param string $body
  98          * @param array $emojis
  99          *
 100          * @return string with replaced emojis
 101          */
 102         private static function replaceEmojis(int $uri_id, string $body, array $emojis): string
 103         {
 104                 $body = strtr($body,
 105                         array_combine(
 106                                 array_column($emojis, 'name'),
 107                                 array_map(function ($emoji) {
 108                                         return '[emoji=' . $emoji['href'] . ']' . $emoji['name'] . '[/emoji]';
 109                                 }, $emojis)
 110                         )
 111                 );
 112
 113                 // We store the emoji here to be able to avoid storing it in the media
 114                 foreach ($emojis as $emoji) {
 115                         Post\Link::getByLink($uri_id, $emoji['href']);
 116                 }
 117                 return $body;
 118         }
 119
 120         /**
 121          * Store attached media files in the post-media table
 122          *
 123          * @param int $uriid
 124          * @param array $attachment
 125          * @return void
 126          */
 127         private static function storeAttachmentAsMedia(int $uriid, array $attachment)
 128         {
 129                 if (empty($attachment['url'])) {
 130                         return;
 131                 }
 132
 133                 $data = ['uri-id' => $uriid];
 134                 $data['type'] = Post\Media::UNKNOWN;
 135                 $data['url'] = $attachment['url'];
 136                 $data['mimetype'] = $attachment['mediaType'] ?? null;
 137                 $data['height'] = $attachment['height'] ?? null;
 138                 $data['width'] = $attachment['width'] ?? null;
 139                 $data['size'] = $attachment['size'] ?? null;
 140                 $data['preview'] = $attachment['image'] ?? null;
 141                 $data['description'] = $attachment['name'] ?? null;
 142
 143                 Post\Media::insert($data);
 144         }
 145
 146         /**
 147          * Stire attachment data
 148          *
 149          * @param array   $activity
 150          * @param array   $item
 151          */
 152         private static function storeAttachments(array $activity, array $item)
 153         {
 154                 if (empty($activity['attachments'])) {
 155                         return;
 156                 }
 157
 158                 foreach ($activity['attachments'] as $attach) {
 159                         self::storeAttachmentAsMedia($item['uri-id'], $attach);
 160                 }
 161         }
 162
 163         /**
 164          * Store attachment data
 165          *
 166          * @param array   $activity
 167          * @param array   $item
 168          */
 169         private static function storeQuestion(array $activity, array $item)
 170         {
 171                 if (empty($activity['question'])) {
 172                         return;
 173                 }
 174                 $question = ['multiple' => $activity['question']['multiple']];
 175
 176                 if (!empty($activity['question']['voters'])) {
 177                         $question['voters'] = $activity['question']['voters'];
 178                 }
 179
 180                 if (!empty($activity['question']['end-time'])) {
 181                         $question['end-time'] = DateTimeFormat::utc($activity['question']['end-time']);
 182                 }
 183
 184                 Post\Question::update($item['uri-id'], $question);
 185
 186                 foreach ($activity['question']['options'] as $key => $option) {
 187                         $option = ['name' => $option['name'], 'replies' => $option['replies']];
 188                         Post\QuestionOption::update($item['uri-id'], $key, $option);
 189                 }
 190
 191                 Logger::debug('Storing incoming question', ['type' => $activity['type'], 'uri-id' => $item['uri-id'], 'question' => $activity['question']]);
 192         }
 193
 194         /**
 195          * Updates a message
 196          *
 197          * @param array      $activity   Activity array
 198          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 199          * @throws \ImagickException
 200          */
 201         public static function updateItem(array $activity)
 202         {
 203                 $item = Post::selectFirst(['uri', 'uri-id', 'thr-parent', 'gravity', 'post-type'], ['uri' => $activity['id']]);
 204                 if (!DBA::isResult($item)) {
 205                         Logger::warning('No existing item, item will be created', ['uri' => $activity['id']]);
 206                         $item = self::createItem($activity);
 207                         if (empty($item)) {
 208                                 return;
 209                         }
 210
 211                         self::postItem($activity, $item);
 212                         return;
 213                 }
 214
 215                 $item['changed'] = DateTimeFormat::utcNow();
 216                 $item['edited'] = DateTimeFormat::utc($activity['updated']);
 217
 218                 $item = self::processContent($activity, $item);
 219                 if (empty($item)) {
 220                         return;
 221                 }
 222
 223                 self::storeAttachments($activity, $item);
 224                 self::storeQuestion($activity, $item);
 225
 226                 Post\History::add($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['author']) && empty($activity['actor'])) {
 304                         Logger::notice('Missing author and actor. We quit here.', ['activity' => $activity]);
 305                         return [];
 306                 }
 307
 308                 if (empty($activity['directmessage']) && ($activity['id'] != $activity['reply-to-id']) && !Post::exists(['uri' => $activity['reply-to-id']])) {
 309                         $result = self::fetchParent($activity);
 310                         if (!empty($result)) {
 311                                 if (($item['thr-parent'] != $result) && Post::exists(['uri' => $result])) {
 312                                         $item['thr-parent'] = $result;
 313                                 }
 314                         } elseif (empty($conversation)) {
 315                                 return [];
 316                         }
 317                 }
 318
 319                 $item['diaspora_signed_text'] = $activity['diaspora:comment'] ?? '';
 320
 321                 if (empty($conversation) && empty($activity['directmessage']) && ($item['gravity'] != GRAVITY_PARENT) && !Post::exists(['uri' => $item['thr-parent']])) {
 322                         Logger::info('Parent not found, message will be discarded.', ['thr-parent' => $item['thr-parent']]);
 323                         return [];
 324                 }
 325
 326                 $item['network'] = Protocol::ACTIVITYPUB;
 327                 $item['author-link'] = $activity['author'];
 328                 $item['author-id'] = Contact::getIdForURL($activity['author']);
 329                 $item['owner-link'] = $activity['actor'];
 330                 $item['owner-id'] = Contact::getIdForURL($activity['actor']);
 331
 332                 if (in_array(0, $activity['receiver']) && !empty($activity['unlisted'])) {
 333                         $item['private'] = Item::UNLISTED;
 334                 } elseif (in_array(0, $activity['receiver'])) {
 335                         $item['private'] = Item::PUBLIC;
 336                 } else {
 337                         $item['private'] = Item::PRIVATE;
 338                 }
 339
 340                 if (!empty($activity['raw'])) {
 341                         $item['source'] = $activity['raw'];
 342                 }
 343
 344                 $item['protocol'] = Conversation::PARCEL_ACTIVITYPUB;
 345
 346                 if (isset($activity['push'])) {
 347                         $item['direction'] = $activity['push'] ? Conversation::PUSH : Conversation::PULL;
 348                 }
 349
 350                 if (!empty($activity['from-relay'])) {
 351                         $item['direction'] = Conversation::RELAY;
 352                 }
 353
 354                 if ($activity['object_type'] == 'as:Article') {
 355                         $item['post-type'] = Item::PT_ARTICLE;
 356                 } elseif ($activity['object_type'] == 'as:Audio') {
 357                         $item['post-type'] = Item::PT_AUDIO;
 358                 } elseif ($activity['object_type'] == 'as:Document') {
 359                         $item['post-type'] = Item::PT_DOCUMENT;
 360                 } elseif ($activity['object_type'] == 'as:Event') {
 361                         $item['post-type'] = Item::PT_EVENT;
 362                 } elseif ($activity['object_type'] == 'as:Image') {
 363                         $item['post-type'] = Item::PT_IMAGE;
 364                 } elseif ($activity['object_type'] == 'as:Page') {
 365                         $item['post-type'] = Item::PT_PAGE;
 366                 } elseif ($activity['object_type'] == 'as:Question') {
 367                         $item['post-type'] = Item::PT_POLL;
 368                 } elseif ($activity['object_type'] == 'as:Video') {
 369                         $item['post-type'] = Item::PT_VIDEO;
 370                 } else {
 371                         $item['post-type'] = Item::PT_NOTE;
 372                 }
 373
 374                 $item['isForum'] = false;
 375
 376                 if (!empty($activity['thread-completion'])) {
 377                         if ($activity['thread-completion'] != $item['owner-id']) {
 378                                 $actor = Contact::getById($activity['thread-completion'], ['url']);
 379                                 $item['causer-link'] = $actor['url'];
 380                                 $item['causer-id'] = $activity['thread-completion'];
 381                                 Logger::info('Use inherited actor as causer.', ['id' => $item['owner-id'], 'activity' => $activity['thread-completion'], 'owner' => $item['owner-link'], 'actor' => $actor['url']]);
 382                         } else {
 383                                 // Store the original actor in the "causer" fields to enable the check for ignored or blocked contacts
 384                                 $item['causer-link'] = $item['owner-link'];
 385                                 $item['causer-id']   = $item['owner-id'];
 386                                 Logger::info('Use actor as causer.', ['id' => $item['owner-id'], 'actor' => $item['owner-link']]);
 387                         }
 388
 389                         $item['owner-link'] = $item['author-link'];
 390                         $item['owner-id'] = $item['author-id'];
 391                 } else {
 392                         $actor = APContact::getByURL($item['owner-link'], false);
 393                         $item['isForum'] = ($actor['type'] == 'Group');
 394                 }
 395
 396                 $item['uri'] = $activity['id'];
 397
 398                 if (empty($activity['published']) || empty($activity['updated'])) {
 399                         DI::logger()->notice('published or updated keys are empty for activity', ['activity' => $activity, 'callstack' => System::callstack(10)]);
 400                 }
 401
 402                 $item['created'] = DateTimeFormat::utc($activity['published'] ?? 'now');
 403                 $item['edited'] = DateTimeFormat::utc($activity['updated'] ?? 'now');
 404                 $guid = $activity['sc:identifier'] ?: self::getGUIDByURL($item['uri']);
 405                 $item['guid'] = $activity['diaspora:guid'] ?: $guid;
 406
 407                 $item['uri-id'] = ItemURI::insert(['uri' => $item['uri'], 'guid' => $item['guid']]);
 408                 if (empty($item['uri-id'])) {
 409                         Logger::warning('Unable to get a uri-id for an item uri', ['uri' => $item['uri'], 'guid' => $item['guid']]);
 410                         return [];
 411                 }
 412
 413                 $item = self::processContent($activity, $item);
 414                 if (empty($item)) {
 415                         Logger::info('Message was not processed');
 416                         return [];
 417                 }
 418
 419                 $item['plink'] = $activity['alternate-url'] ?? $item['uri'];
 420
 421                 self::storeAttachments($activity, $item);
 422                 self::storeQuestion($activity, $item);
 423
 424                 // We received the post via AP, so we set the protocol of the server to AP
 425                 $contact = Contact::getById($item['author-id'], ['gsid']);
 426                 if (!empty($contact['gsid'])) {
 427                         GServer::setProtocol($contact['gsid'], Post\DeliveryData::ACTIVITYPUB);
 428                 }
 429
 430                 if ($item['author-id'] != $item['owner-id']) {
 431                         $contact = Contact::getById($item['owner-id'], ['gsid']);
 432                         if (!empty($contact['gsid'])) {
 433                                 GServer::setProtocol($contact['gsid'], Post\DeliveryData::ACTIVITYPUB);
 434                         }
 435                 }
 436
 437                 return $item;
 438         }
 439
 440         /**
 441          * Fetch and process parent posts for the given activity
 442          *
 443          * @param array $activity
 444          *
 445          * @return string
 446          */
 447         private static function fetchParent(array $activity): string
 448         {
 449                 if (self::hasJustBeenFetched($activity['reply-to-id'])) {
 450                         Logger::notice('We just have tried to fetch this activity. We don\'t try it again.', ['parent' => $activity['reply-to-id']]);
 451                         return '';
 452                 }
 453
 454                 $recursion_depth = $activity['recursion-depth'] ?? 0;
 455
 456                 if ($recursion_depth < DI::config()->get('system', 'max_recursion_depth')) {
 457                         Logger::notice('Parent not found. Try to refetch it.', ['parent' => $activity['reply-to-id'], 'recursion-depth' => $recursion_depth]);
 458                         $result = self::fetchMissingActivity($activity['reply-to-id'], $activity, '', Receiver::COMPLETION_AUTO);
 459                         if (empty($result) && self::isActivityGone($activity['reply-to-id'])) {
 460                                 Logger::notice('The activity is gone, the queue entry will be deleted', ['parent' => $activity['reply-to-id']]);
 461                                 if (!empty($activity['entry-id'])) {
 462                                         Queue::deleteById($activity['entry-id']);
 463                                 }
 464                                 return '';
 465                         } elseif (!empty($result)) {
 466                                 $exists = Post::exists(['uri' => [$result, $activity['reply-to-id']]]);
 467                                 if ($exists) {
 468                                         Logger::notice('The activity has been fetched and created.', ['parent' => $result]);
 469                                         return $result;
 470                                 } elseif (DI::config()->get('system', 'fetch_by_worker') || DI::config()->get('system', 'decoupled_receiver')) {
 471                                         Logger::notice('The activity has been fetched and will hopefully be created later.', ['parent' => $result]);
 472                                 } else {
 473                                         Logger::notice('The activity exists but has not been created, the queue entry will be deleted.', ['parent' => $result]);
 474                                         if (!empty($activity['entry-id'])) {
 475                                                 Queue::deleteById($activity['entry-id']);
 476                                         }
 477                                 }
 478                                 return '';
 479                         }
 480                         if (empty($result) && !DI::config()->get('system', 'fetch_by_worker')) {
 481                                 return '';
 482                         }
 483                 } elseif (self::isActivityGone($activity['reply-to-id'])) {
 484                         Logger::notice('The activity is gone. We will not spawn a worker. The queue entry will be deleted', ['parent' => $activity['reply-to-id']]);
 485                         if (!empty($activity['entry-id'])) {
 486                                 Queue::deleteById($activity['entry-id']);
 487                         }
 488                         return '';
 489                 } else {
 490                         Logger::notice('Recursion level is too high.', ['parent' => $activity['reply-to-id'], 'recursion-depth' => $recursion_depth]);
 491                 }
 492
 493                 if (Queue::hasWorker($activity['worker-id'] ?? 0)) {
 494                         Logger::notice('There is already a worker task to fetch the post.', ['id' => $activity['id'], 'parent' => $activity['reply-to-id']]);
 495                         return '';
 496                 }
 497
 498                 if (!Fetch::hasWorker($activity['reply-to-id'])) {
 499                         Logger::notice('Fetching is done by worker.', ['parent' => $activity['reply-to-id'], 'recursion-depth' => $recursion_depth]);
 500                         Fetch::add($activity['reply-to-id']);
 501                         $activity['recursion-depth'] = 0;
 502                         $wid = Worker::add(PRIORITY_HIGH, 'FetchMissingActivity', $activity['reply-to-id'], $activity, '', Receiver::COMPLETION_AUTO);
 503                         Fetch::setWorkerId($activity['reply-to-id'], $wid);
 504                 } else {
 505                         Logger::debug('Activity will already be fetched via a worker.', ['url' => $activity['reply-to-id']]);
 506                 }
 507
 508                 return '';
 509         }
 510
 511         /**
 512          * Check if a given activity has recently been fetched
 513          *
 514          * @param string $url
 515          * @return boolean
 516          */
 517         private static function hasJustBeenFetched(string $url): bool
 518         {
 519                 $cachekey = self::CACHEKEY_JUST_FETCHED . $url;
 520                 $time = DI::cache()->get($cachekey);
 521                 if (is_null($time)) {
 522                         DI::cache()->set($cachekey, time(), Duration::FIVE_MINUTES);
 523                         return false;
 524                 }
 525                 return ($time + 300) > time();
 526         }
 527
 528         /**
 529          * Check if a given activity is no longer available
 530          *
 531          * @param string $url
 532          *
 533          * @return boolean
 534          */
 535         public static function isActivityGone(string $url): bool
 536         {
 537                 $curlResult = HTTPSignature::fetchRaw($url, 0);
 538
 539                 if (Network::isUrlBlocked($url)) {
 540                         return true;
 541                 }
 542
 543                 // @todo To ensure that the remote system is working correctly, we can check if the "Content-Type" contains JSON
 544                 if (in_array($curlResult->getReturnCode(), [404])) {
 545                         return true;
 546                 }
 547
 548                 $object = json_decode($curlResult->getBody(), true);
 549                 if (!empty($object)) {
 550                         $activity = JsonLD::compact($object);
 551                         if (JsonLD::fetchElement($activity, '@type') == 'as:Tombstone') {
 552                                 return true;
 553                         }
 554                 }
 555
 556                 return false;
 557         }
 558         /**
 559          * Delete items
 560          *
 561          * @param array $activity
 562          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 563          * @throws \ImagickException
 564          */
 565         public static function deleteItem(array $activity)
 566         {
 567                 $owner = Contact::getIdForURL($activity['actor']);
 568
 569                 Logger::info('Deleting item', ['object' => $activity['object_id'], 'owner'  => $owner]);
 570                 Item::markForDeletion(['uri' => $activity['object_id'], 'owner-id' => $owner]);
 571                 Queue::remove($activity);
 572         }
 573
 574         /**
 575          * Prepare the item array for an activity
 576          *
 577          * @param array $activity Activity array
 578          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 579          * @throws \ImagickException
 580          */
 581         public static function addTag(array $activity)
 582         {
 583                 if (empty($activity['object_content']) || empty($activity['object_id'])) {
 584                         return;
 585                 }
 586
 587                 foreach ($activity['receiver'] as $receiver) {
 588                         $item = Post::selectFirst(['id', 'uri-id', 'origin', 'author-link'], ['uri' => $activity['target_id'], 'uid' => $receiver]);
 589                         if (!DBA::isResult($item)) {
 590                                 // We don't fetch missing content for this purpose
 591                                 continue;
 592                         }
 593
 594                         if (($item['author-link'] != $activity['actor']) && !$item['origin']) {
 595                                 Logger::info('Not origin, not from the author, skipping update', ['id' => $item['id'], 'author' => $item['author-link'], 'actor' => $activity['actor']]);
 596                                 continue;
 597                         }
 598
 599                         Tag::store($item['uri-id'], Tag::HASHTAG, $activity['object_content'], $activity['object_id']);
 600                         Logger::info('Tagged item', ['id' => $item['id'], 'tag' => $activity['object_content'], 'uri' => $activity['target_id'], 'actor' => $activity['actor']]);
 601                 }
 602         }
 603
 604         /**
 605          * Prepare the item array for an activity
 606          *
 607          * @param array      $activity   Activity array
 608          * @param string     $verb       Activity verb
 609          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 610          * @throws \ImagickException
 611          */
 612         public static function createActivity(array $activity, string $verb)
 613         {
 614                 $activity['reply-to-id'] = $activity['object_id'];
 615                 $item = self::createItem($activity);
 616                 if (empty($item)) {
 617                         return;
 618                 }
 619
 620                 $item['verb'] = $verb;
 621                 $item['thr-parent'] = $activity['object_id'];
 622                 $item['gravity'] = GRAVITY_ACTIVITY;
 623                 unset($item['post-type']);
 624                 $item['object-type'] = Activity\ObjectType::NOTE;
 625
 626                 if (!empty($activity['content'])) {
 627                         $item['body'] = HTML::toBBCode($activity['content']);
 628                 }
 629
 630                 $item['diaspora_signed_text'] = $activity['diaspora:like'] ?? '';
 631
 632                 self::postItem($activity, $item);
 633         }
 634
 635         /**
 636          * Fetch the Uri-Id of a post for the "featured" collection
 637          *
 638          * @param array $activity
 639          * @return null|int
 640          */
 641         private static function getUriIdForFeaturedCollection(array $activity)
 642         {
 643                 $actor = APContact::getByURL($activity['actor']);
 644                 if (empty($actor)) {
 645                         return null;
 646                 }
 647
 648                 // Refetch the account when the "featured" collection is missing.
 649                 // This can be removed in a future version (end of 2022 should be good).
 650                 if (empty($actor['featured'])) {
 651                         $actor = APContact::getByURL($activity['actor'], true);
 652                         if (empty($actor)) {
 653                                 return null;
 654                         }
 655                 }
 656
 657                 $parent = Post::selectFirst(['uri-id'], ['uri' => $activity['object_id']]);
 658                 if (empty($parent['uri-id'])) {
 659                         if (self::fetchMissingActivity($activity['object_id'], $activity, '', Receiver::COMPLETION_AUTO)) {
 660                                 $parent = Post::selectFirst(['uri-id'], ['uri' => $activity['object_id']]);
 661                         }
 662                 }
 663
 664                 if (!empty($parent['uri-id'])) {
 665                         return $parent['uri-id'];
 666                 }
 667
 668                 return null;
 669         }
 670
 671         /**
 672          * Add a post to the "Featured" collection
 673          *
 674          * @param array $activity
 675          */
 676         public static function addToFeaturedCollection(array $activity)
 677         {
 678                 $uriid = self::getUriIdForFeaturedCollection($activity);
 679                 if (empty($uriid)) {
 680                         return;
 681                 }
 682
 683                 Logger::debug('Add post to featured collection', ['uri-id' => $uriid]);
 684
 685                 Post\Collection::add($uriid, Post\Collection::FEATURED);
 686                 Queue::remove($activity);
 687         }
 688
 689         /**
 690          * Remove a post to the "Featured" collection
 691          *
 692          * @param array $activity
 693          */
 694         public static function removeFromFeaturedCollection(array $activity)
 695         {
 696                 $uriid = self::getUriIdForFeaturedCollection($activity);
 697                 if (empty($uriid)) {
 698                         return;
 699                 }
 700
 701                 Logger::debug('Remove post from featured collection', ['uri-id' => $uriid]);
 702
 703                 Post\Collection::remove($uriid, Post\Collection::FEATURED);
 704                 Queue::remove($activity);
 705         }
 706
 707         /**
 708          * Create an event
 709          *
 710          * @param array $activity Activity array
 711          * @param array $item
 712          *
 713          * @return int event id
 714          * @throws \Exception
 715          */
 716         public static function createEvent(array $activity, array $item): int
 717         {
 718                 $event['summary']   = HTML::toBBCode($activity['name'] ?: $activity['summary']);
 719                 $event['desc']      = HTML::toBBCode($activity['content']);
 720                 if (!empty($activity['start-time'])) {
 721                         $event['start']  = DateTimeFormat::utc($activity['start-time']);
 722                 }
 723                 if (!empty($activity['end-time'])) {
 724                         $event['finish'] = DateTimeFormat::utc($activity['end-time']);
 725                 }
 726                 $event['nofinish']  = empty($event['finish']);
 727                 $event['location']  = $activity['location'];
 728                 $event['cid']       = $item['contact-id'];
 729                 $event['uid']       = $item['uid'];
 730                 $event['uri']       = $item['uri'];
 731                 $event['edited']    = $item['edited'];
 732                 $event['private']   = $item['private'];
 733                 $event['guid']      = $item['guid'];
 734                 $event['plink']     = $item['plink'];
 735                 $event['network']   = $item['network'];
 736                 $event['protocol']  = $item['protocol'];
 737                 $event['direction'] = $item['direction'];
 738                 $event['source']    = $item['source'];
 739
 740                 $ev = DBA::selectFirst('event', ['id'], ['uri' => $item['uri'], 'uid' => $item['uid']]);
 741                 if (DBA::isResult($ev)) {
 742                         $event['id'] = $ev['id'];
 743                 }
 744
 745                 $event_id = Event::store($event);
 746
 747                 Logger::info('Event was stored', ['id' => $event_id]);
 748
 749                 return $event_id;
 750         }
 751
 752         /**
 753          * Process the content
 754          *
 755          * @param array $activity Activity array
 756          * @param array $item
 757          * @return array|bool Returns the item array or false if there was an unexpected occurrence
 758          * @throws \Exception
 759          */
 760         private static function processContent(array $activity, array $item)
 761         {
 762                 if (!empty($activity['mediatype']) && ($activity['mediatype'] == 'text/markdown')) {
 763                         $item['title'] = strip_tags($activity['name']);
 764                         $content = Markdown::toBBCode($activity['content']);
 765                 } elseif (!empty($activity['mediatype']) && ($activity['mediatype'] == 'text/bbcode')) {
 766                         $item['title'] = $activity['name'];
 767                         $content = $activity['content'];
 768                 } else {
 769                         // By default assume "text/html"
 770                         $item['title'] = HTML::toBBCode($activity['name'] ?? '');
 771                         $content = HTML::toBBCode($activity['content'] ?? '');
 772                 }
 773
 774                 $item['title'] = trim(BBCode::toPlaintext($item['title']));
 775
 776                 if (!empty($activity['languages'])) {
 777                         $item['language'] = self::processLanguages($activity['languages']);
 778                 }
 779
 780                 if (!empty($activity['emojis'])) {
 781                         $content = self::replaceEmojis($item['uri-id'], $content, $activity['emojis']);
 782                 }
 783
 784                 $content = self::addMentionLinks($content, $activity['tags']);
 785
 786                 if (!empty($activity['source'])) {
 787                         $item['body'] = $activity['source'];
 788                         $item['raw-body'] = $content;
 789                         $item['body'] = Item::improveSharedDataInBody($item);
 790                 } else {
 791                         $parent_uri = $item['parent-uri'] ?? $item['thr-parent'];
 792                         if (empty($activity['directmessage']) && ($parent_uri != $item['uri']) && ($item['gravity'] == GRAVITY_COMMENT)) {
 793                                 $parent = Post::selectFirst(['id', 'uri-id', 'private', 'author-link', 'alias'], ['uri' => $parent_uri]);
 794                                 if (!DBA::isResult($parent)) {
 795                                         Logger::warning('Unknown parent item.', ['uri' => $parent_uri]);
 796                                         return false;
 797                                 }
 798                                 if (($item['private'] == Item::PRIVATE) && ($parent['private'] != Item::PRIVATE)) {
 799                                         Logger::warning('Item is private but the parent is not. Dropping.', ['item-uri' => $item['uri'], 'thr-parent' => $item['thr-parent']]);
 800                                         return false;
 801                                 }
 802
 803                                 $content = self::removeImplicitMentionsFromBody($content, $parent);
 804                         }
 805                         $item['content-warning'] = HTML::toBBCode($activity['summary'] ?? '');
 806                         $item['raw-body'] = $item['body'] = $content;
 807                 }
 808
 809                 self::storeFromBody($item);
 810                 self::storeTags($item['uri-id'], $activity['tags']);
 811
 812                 self::storeReceivers($item['uri-id'], $activity['receiver_urls'] ?? []);
 813
 814                 $item['location'] = $activity['location'];
 815
 816                 if (!empty($activity['latitude']) && !empty($activity['longitude'])) {
 817                         $item['coord'] = $activity['latitude'] . ' ' . $activity['longitude'];
 818                 }
 819
 820                 $item['app'] = $activity['generator'];
 821
 822                 return $item;
 823         }
 824
 825         /**
 826          * Store hashtags and mentions
 827          *
 828          * @param array $item
 829          */
 830         private static function storeFromBody(array $item)
 831         {
 832                 // Make sure to delete all existing tags (can happen when called via the update functionality)
 833                 DBA::delete('post-tag', ['uri-id' => $item['uri-id']]);
 834
 835                 Tag::storeFromBody($item['uri-id'], $item['body'], '@!');
 836         }
 837
 838         /**
 839          * Generate a GUID out of an URL of an ActivityPub post.
 840          *
 841          * @param string $url message URL
 842          * @return string with GUID
 843          */
 844         private static function getGUIDByURL(string $url): string
 845         {
 846                 $parsed = parse_url($url);
 847
 848                 $host_hash = hash('crc32', $parsed['host']);
 849
 850                 unset($parsed["scheme"]);
 851                 unset($parsed["host"]);
 852
 853                 $path = implode("/", $parsed);
 854
 855                 return $host_hash . '-'. hash('fnv164', $path) . '-'. hash('joaat', $path);
 856         }
 857
 858         /**
 859          * Checks if an incoming message is wanted
 860          *
 861          * @param array $activity
 862          * @param array $item
 863          * @return boolean Is the message wanted?
 864          */
 865         private static function isSolicitedMessage(array $activity, array $item): bool
 866         {
 867                 // The checks are split to improve the support when searching why a message was accepted.
 868                 if (count($activity['receiver']) != 1) {
 869                         // The message has more than one receiver, so it is wanted.
 870                         Logger::debug('Message has got several receivers - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 871                         return true;
 872                 }
 873
 874                 if ($item['private'] == Item::PRIVATE) {
 875                         // We only look at public posts here. Private posts are expected to be intentionally posted to the single receiver.
 876                         Logger::debug('Message is private - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 877                         return true;
 878                 }
 879
 880                 if (!empty($activity['from-relay'])) {
 881                         // We check relay posts at another place. When it arrived here, the message is already checked.
 882                         Logger::debug('Message is a relay post that is already checked - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 883                         return true;
 884                 }
 885
 886                 if (in_array($activity['completion-mode'] ?? Receiver::COMPLETION_NONE, [Receiver::COMPLETION_MANUAL, Receiver::COMPLETION_ANNOUCE])) {
 887                         // Manual completions and completions caused by reshares are allowed without any further checks.
 888                         Logger::debug('Message is in completion mode - accepted', ['mode' => $activity['completion-mode'], 'uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 889                         return true;
 890                 }
 891
 892                 if ($item['gravity'] != GRAVITY_PARENT) {
 893                         // We cannot reliably check at this point if a comment or activity belongs to an accepted post or needs to be fetched
 894                         // This can possibly be improved in the future.
 895                         Logger::debug('Message is no parent - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 896                         return true;
 897                 }
 898
 899                 $tags = array_column(Tag::getByURIId($item['uri-id'], [Tag::HASHTAG]), 'name');
 900                 if (Relay::isSolicitedPost($tags, $item['body'], $item['author-id'], $item['uri'], Protocol::ACTIVITYPUB)) {
 901                         Logger::debug('Post is accepted because of the relay settings', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 902                         return true;
 903                 } else {
 904                         return false;
 905                 }
 906         }
 907
 908         /**
 909          * Creates an item post
 910          *
 911          * @param array $activity Activity data
 912          * @param array $item     item array
 913          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 914          * @throws \ImagickException
 915          */
 916         public static function postItem(array $activity, array $item)
 917         {
 918                 if (empty($item)) {
 919                         return;
 920                 }
 921
 922                 $stored = false;
 923                 $success = false;
 924                 ksort($activity['receiver']);
 925
 926                 if (!self::isSolicitedMessage($activity, $item)) {
 927                         DBA::delete('item-uri', ['id' => $item['uri-id']]);
 928                         return;
 929                 }
 930
 931                 foreach ($activity['receiver'] as $receiver) {
 932                         if ($receiver == -1) {
 933                                 continue;
 934                         }
 935
 936                         $item['uid'] = $receiver;
 937
 938                         $type = $activity['reception_type'][$receiver] ?? Receiver::TARGET_UNKNOWN;
 939                         switch($type) {
 940                                 case Receiver::TARGET_TO:
 941                                         $item['post-reason'] = Item::PR_TO;
 942                                         break;
 943                                 case Receiver::TARGET_CC:
 944                                         $item['post-reason'] = Item::PR_CC;
 945                                         break;
 946                                 case Receiver::TARGET_BTO:
 947                                         $item['post-reason'] = Item::PR_BTO;
 948                                         break;
 949                                 case Receiver::TARGET_BCC:
 950                                         $item['post-reason'] = Item::PR_BCC;
 951                                         break;
 952                                 case Receiver::TARGET_FOLLOWER:
 953                                         $item['post-reason'] = Item::PR_FOLLOWER;
 954                                         break;
 955                                 case Receiver::TARGET_ANSWER:
 956                                         $item['post-reason'] = Item::PR_COMMENT;
 957                                         break;
 958                                 case Receiver::TARGET_GLOBAL:
 959                                         $item['post-reason'] = Item::PR_GLOBAL;
 960                                         break;
 961                                 default:
 962                                         $item['post-reason'] = Item::PR_NONE;
 963                         }
 964
 965                         if (!empty($activity['from-relay'])) {
 966                                 $item['post-reason'] = Item::PR_RELAY;
 967                         } elseif (!empty($activity['thread-completion'])) {
 968                                 $item['post-reason'] = Item::PR_FETCHED;
 969                         } elseif (in_array($item['post-reason'], [Item::PR_GLOBAL, Item::PR_NONE]) && !empty($activity['push'])) {
 970                                 $item['post-reason'] = Item::PR_PUSHED;
 971                         }
 972
 973                         if ($item['isForum'] ?? false) {
 974                                 $item['contact-id'] = Contact::getIdForURL($activity['actor'], $receiver);
 975                         } else {
 976                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver);
 977                         }
 978
 979                         if (($receiver != 0) && empty($item['contact-id'])) {
 980                                 $item['contact-id'] = Contact::getIdForURL($activity['author']);
 981                         }
 982
 983                         if (!empty($activity['directmessage'])) {
 984                                 self::postMail($activity, $item);
 985                                 continue;
 986                         }
 987
 988                         if (!($item['isForum'] ?? false) && ($receiver != 0) && ($item['gravity'] == GRAVITY_PARENT) && !Contact::isSharingByURL($activity['author'], $receiver)) {
 989                                 if ($item['post-reason'] == Item::PR_BCC) {
 990                                         Logger::info('Top level post via BCC from a non sharer, ignoring', ['uid' => $receiver, 'contact' => $item['contact-id']]);
 991                                         continue;
 992                                 }
 993
 994                                 if (
 995                                         !empty($activity['thread-children-type'])
 996                                         && in_array($activity['thread-children-type'], Receiver::ACTIVITY_TYPES)
 997                                         && DI::pConfig()->get($receiver, 'system', 'accept_only_sharer') != Item::COMPLETION_LIKE
 998                                 ) {
 999                                         Logger::info('Top level post from thread completion from a non sharer had been initiated via an activity, ignoring',
1000                                                 ['type' => $activity['thread-children-type'], 'user' => $item['uid'], 'causer' => $item['causer-link'], 'author' => $activity['author'], 'url' => $item['uri']]);
1001                                         continue;
1002                                 }
1003                         }
1004
1005                         $is_forum = false;
1006
1007                         if ($receiver != 0) {
1008                                 $user = User::getById($receiver, ['account-type']);
1009                                 if (!empty($user['account-type'])) {
1010                                         $is_forum = ($user['account-type'] == User::ACCOUNT_TYPE_COMMUNITY);
1011                                 }
1012                         }
1013
1014                         if (!$is_forum && DI::pConfig()->get($receiver, 'system', 'accept_only_sharer') == Item::COMPLETION_NONE && ($receiver != 0) && ($item['gravity'] == GRAVITY_PARENT)) {
1015                                 $skip = !Contact::isSharingByURL($activity['author'], $receiver);
1016
1017                                 if ($skip && (($activity['type'] == 'as:Announce') || ($item['isForum'] ?? false))) {
1018                                         $skip = !Contact::isSharingByURL($activity['actor'], $receiver);
1019                                 }
1020
1021                                 if ($skip) {
1022                                         Logger::info('Skipping post', ['uid' => $receiver, 'url' => $item['uri']]);
1023                                         continue;
1024                                 }
1025
1026                                 Logger::info('Accepting post', ['uid' => $receiver, 'url' => $item['uri']]);
1027                         }
1028
1029                         if (($item['gravity'] != GRAVITY_ACTIVITY) && ($activity['object_type'] == 'as:Event')) {
1030                                 $event_id = self::createEvent($activity, $item);
1031
1032                                 $item = Event::getItemArrayForImportedId($event_id, $item);
1033                         }
1034
1035                         $item_id = Item::insert($item);
1036                         if ($item_id) {
1037                                 Logger::info('Item insertion successful', ['user' => $item['uid'], 'item_id' => $item_id]);
1038                                 $success = true;
1039                         } else {
1040                                 Logger::notice('Item insertion aborted', ['uri' => $item['uri'], 'uid' => $item['uid']]);
1041                         }
1042
1043                         if ($item['uid'] == 0) {
1044                                 $stored = $item_id;
1045                         }
1046                 }
1047
1048                 Queue::remove($activity);
1049
1050                 if ($success && Queue::hasChildren($item['uri'])) {
1051                         Queue::processReplyByUri($item['uri']);
1052                 }
1053
1054                 // Store send a follow request for every reshare - but only when the item had been stored
1055                 if ($stored && ($item['private'] != Item::PRIVATE) && ($item['gravity'] == GRAVITY_PARENT) && !empty($item['author-link']) && ($item['author-link'] != $item['owner-link'])) {
1056                         $author = APContact::getByURL($item['owner-link'], false);
1057                         // We send automatic follow requests for reshared messages. (We don't need though for forum posts)
1058                         if ($author['type'] != 'Group') {
1059                                 Logger::info('Send follow request', ['uri' => $item['uri'], 'stored' => $stored, 'to' => $item['author-link']]);
1060                                 ActivityPub\Transmitter::sendFollowObject($item['uri'], $item['author-link']);
1061                         }
1062                 }
1063         }
1064
1065         /**
1066          * Store tags and mentions into the tag table
1067          *
1068          * @param integer $uriid
1069          * @param array $tags
1070          */
1071         private static function storeTags(int $uriid, array $tags = null)
1072         {
1073                 foreach ($tags as $tag) {
1074                         if (empty($tag['name']) || empty($tag['type']) || !in_array($tag['type'], ['Mention', 'Hashtag'])) {
1075                                 continue;
1076                         }
1077
1078                         $hash = substr($tag['name'], 0, 1);
1079
1080                         if ($tag['type'] == 'Mention') {
1081                                 if (in_array($hash, [Tag::TAG_CHARACTER[Tag::MENTION],
1082                                         Tag::TAG_CHARACTER[Tag::EXCLUSIVE_MENTION],
1083                                         Tag::TAG_CHARACTER[Tag::IMPLICIT_MENTION]])) {
1084                                         $tag['name'] = substr($tag['name'], 1);
1085                                 }
1086                                 $type = Tag::IMPLICIT_MENTION;
1087
1088                                 if (!empty($tag['href'])) {
1089                                         $apcontact = APContact::getByURL($tag['href']);
1090                                         if (!empty($apcontact['name']) || !empty($apcontact['nick'])) {
1091                                                 $tag['name'] = $apcontact['name'] ?: $apcontact['nick'];
1092                                         }
1093                                 }
1094                         } elseif ($tag['type'] == 'Hashtag') {
1095                                 if ($hash == Tag::TAG_CHARACTER[Tag::HASHTAG]) {
1096                                         $tag['name'] = substr($tag['name'], 1);
1097                                 }
1098                                 $type = Tag::HASHTAG;
1099                         }
1100
1101                         if (empty($tag['name'])) {
1102                                 continue;
1103                         }
1104
1105                         Tag::store($uriid, $type, $tag['name'], $tag['href']);
1106                 }
1107         }
1108
1109         public static function storeReceivers(int $uriid, array $receivers)
1110         {
1111                 foreach (['as:to' => Tag::TO, 'as:cc' => Tag::CC, 'as:bto' => Tag::BTO, 'as:bcc' => Tag::BCC] as $element => $type) {
1112                         if (!empty($receivers[$element])) {
1113                                 foreach ($receivers[$element] as $receiver) {
1114                                         if ($receiver == ActivityPub::PUBLIC_COLLECTION) {
1115                                                 $name = Receiver::PUBLIC_COLLECTION;
1116                                         } else {
1117                                                 $name = trim(parse_url($receiver, PHP_URL_PATH), '/');
1118                                         }
1119
1120                                         $target = Tag::getTargetType($receiver);
1121                                         Logger::debug('Got target type', ['type' => $target, 'url' => $receiver]);
1122                                         Tag::store($uriid, $type, $name, $receiver, $target);
1123                                 }
1124                         }
1125                 }
1126         }
1127
1128         /**
1129          * Creates an mail post
1130          *
1131          * @param array $activity Activity data
1132          * @param array $item     item array
1133          * @return int|bool New mail table row id or false on error
1134          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1135          */
1136         private static function postMail(array $activity, array $item)
1137         {
1138                 if (($item['gravity'] != GRAVITY_PARENT) && !DBA::exists('mail', ['uri' => $item['thr-parent'], 'uid' => $item['uid']])) {
1139                         Logger::info('Parent not found, mail will be discarded.', ['uid' => $item['uid'], 'uri' => $item['thr-parent']]);
1140                         return false;
1141                 }
1142
1143                 Logger::info('Direct Message', $item);
1144
1145                 $msg = [];
1146                 $msg['uid'] = $item['uid'];
1147
1148                 $msg['contact-id'] = $item['contact-id'];
1149
1150                 $contact = Contact::getById($item['contact-id'], ['name', 'url', 'photo']);
1151                 $msg['from-name'] = $contact['name'];
1152                 $msg['from-url'] = $contact['url'];
1153                 $msg['from-photo'] = $contact['photo'];
1154
1155                 $msg['uri'] = $item['uri'];
1156                 $msg['created'] = $item['created'];
1157
1158                 $parent = DBA::selectFirst('mail', ['parent-uri', 'title'], ['uri' => $item['thr-parent']]);
1159                 if (DBA::isResult($parent)) {
1160                         $msg['parent-uri'] = $parent['parent-uri'];
1161                         $msg['title'] = $parent['title'];
1162                 } else {
1163                         $msg['parent-uri'] = $item['thr-parent'];
1164
1165                         if (!empty($item['title'])) {
1166                                 $msg['title'] = $item['title'];
1167                         } elseif (!empty($item['content-warning'])) {
1168                                 $msg['title'] = $item['content-warning'];
1169                         } else {
1170                                 // Trying to generate a title out of the body
1171                                 $title = $item['body'];
1172
1173                                 while (preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $title, $matches)) {
1174                                         $title = $matches[3];
1175                                 }
1176
1177                                 $title = trim(BBCode::toPlaintext($title));
1178
1179                                 if (strlen($title) > 20) {
1180                                         $title = substr($title, 0, 20) . '...';
1181                                 }
1182
1183                                 $msg['title'] = $title;
1184                         }
1185                 }
1186                 $msg['body'] = $item['body'];
1187
1188                 return Mail::insert($msg);
1189         }
1190
1191         /**
1192          * Fetch featured posts from a contact with the given url
1193          *
1194          * @param string $url
1195          * @return void
1196          */
1197         public static function fetchFeaturedPosts(string $url)
1198         {
1199                 Logger::info('Fetch featured posts', ['contact' => $url]);
1200
1201                 $apcontact = APContact::getByURL($url);
1202                 if (empty($apcontact['featured'])) {
1203                         Logger::info('Contact does not have a featured collection', ['contact' => $url]);
1204                         return;
1205                 }
1206
1207                 $pcid = Contact::getIdForURL($url, 0, false);
1208                 if (empty($pcid)) {
1209                         Logger::info('Contact not found', ['contact' => $url]);
1210                         return;
1211                 }
1212
1213                 $posts = Post\Collection::selectToArrayForContact($pcid, Post\Collection::FEATURED);
1214                 if (!empty($posts)) {
1215                         $old_featured = array_column($posts, 'uri-id');
1216                 } else {
1217                         $old_featured = [];
1218                 }
1219
1220                 $featured = ActivityPub::fetchItems($apcontact['featured']);
1221                 if (empty($featured)) {
1222                         Logger::info('Contact does not have featured posts', ['contact' => $url]);
1223
1224                         foreach ($old_featured as $uri_id) {
1225                                 Post\Collection::remove($uri_id, Post\Collection::FEATURED);
1226                                 Logger::debug('Removed no longer featured post', ['uri-id' => $uri_id, 'contact' => $url]);
1227                         }
1228                         return;
1229                 }
1230
1231                 $new = 0;
1232                 $old = 0;
1233
1234                 foreach ($featured as $post) {
1235                         if (empty($post['id'])) {
1236                                 continue;
1237                         }
1238                         $id = Item::fetchByLink($post['id']);
1239                         if (!empty($id)) {
1240                                 $item = Post::selectFirst(['uri-id', 'featured'], ['id' => $id]);
1241                                 if (!empty($item['uri-id'])) {
1242                                         if (!$item['featured']) {
1243                                                 Post\Collection::add($item['uri-id'], Post\Collection::FEATURED);
1244                                                 Logger::debug('Added featured post', ['uri-id' => $item['uri-id'], 'contact' => $url]);
1245                                                 $new++;
1246                                         } else {
1247                                                 Logger::debug('Post already had been featured', ['uri-id' => $item['uri-id'], 'contact' => $url]);
1248                                                 $old++;
1249                                         }
1250
1251                                         $index = array_search($item['uri-id'], $old_featured);
1252                                         if (!($index === false)) {
1253                                                 unset($old_featured[$index]);
1254                                         }
1255                                 }
1256                         }
1257                 }
1258
1259                 foreach ($old_featured as $uri_id) {
1260                         Post\Collection::remove($uri_id, Post\Collection::FEATURED);
1261                         Logger::debug('Removed no longer featured post', ['uri-id' => $uri_id, 'contact' => $url]);
1262                 }
1263
1264                 Logger::info('Fetched featured posts', ['new' => $new, 'old' => $old, 'contact' => $url]);
1265         }
1266
1267         public static function fetchCachedActivity(string $url, int $uid): array
1268         {
1269                 $cachekey = self::CACHEKEY_FETCH_ACTIVITY . $uid . ':' . $url;
1270                 $object = DI::cache()->get($cachekey);
1271
1272                 if (!is_null($object)) {
1273                         if (!empty($object)) {
1274                                 Logger::debug('Fetch from cache', ['url' => $url, 'uid' => $uid]);
1275                         } else {
1276                                 Logger::debug('Fetch from negative cache', ['url' => $url, 'uid' => $uid]);
1277                         }
1278                         return $object;
1279                 }
1280
1281                 $object = ActivityPub::fetchContent($url, $uid);
1282                 if (empty($object)) {
1283                         Logger::notice('Activity was not fetchable, aborting.', ['url' => $url, 'uid' => $uid]);
1284                         // We perform negative caching.
1285                         DI::cache()->set($cachekey, [], Duration::FIVE_MINUTES);
1286                         return [];
1287                 }
1288
1289                 if (empty($object['id'])) {
1290                         Logger::notice('Activity has got not id, aborting. ', ['url' => $url, 'object' => $object]);
1291                         return [];
1292                 }
1293                 DI::cache()->set($cachekey, $object, Duration::FIVE_MINUTES);
1294
1295                 Logger::debug('Activity was fetched successfully', ['url' => $url, 'uid' => $uid]);
1296
1297                 return $object;
1298         }
1299
1300         /**
1301          * Fetches missing posts
1302          *
1303          * @param string     $url         message URL
1304          * @param array      $child       activity array with the child of this message
1305          * @param string     $relay_actor Relay actor
1306          * @param int        $completion  Completion mode, see Receiver::COMPLETION_*
1307          * @return string fetched message URL
1308          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1309          * @throws \ImagickException
1310          */
1311         public static function fetchMissingActivity(string $url, array $child = [], string $relay_actor = '', int $completion = Receiver::COMPLETION_MANUAL): string
1312         {
1313                 if (!empty($child['receiver'])) {
1314                         $uid = ActivityPub\Receiver::getFirstUserFromReceivers($child['receiver']);
1315                 } else {
1316                         $uid = 0;
1317                 }
1318
1319                 $object = self::fetchCachedActivity($url, $uid);
1320                 if (empty($object)) {
1321                         return '';
1322                 }
1323
1324                 $signer = [];
1325
1326                 if (!empty($object['attributedTo'])) {
1327                         $attributed_to = $object['attributedTo'];
1328                         if (is_array($attributed_to)) {
1329                                 $compacted = JsonLD::compact($object);
1330                                 $attributed_to = JsonLD::fetchElement($compacted, 'as:attributedTo', '@id');
1331                         }
1332                         $signer[] = $attributed_to;
1333                 }
1334
1335                 if (!empty($object['actor'])) {
1336                         $object_actor = $object['actor'];
1337                 } elseif (!empty($attributed_to)) {
1338                         $object_actor = $attributed_to;
1339                 } else {
1340                         // Shouldn't happen
1341                         $object_actor = '';
1342                 }
1343
1344                 $signer[] = $object_actor;
1345
1346                 if (!empty($child['author'])) {
1347                         $actor = $child['author'];
1348                         $signer[] = $actor;
1349                 } else {
1350                         $actor = $object_actor;
1351                 }
1352
1353                 if (!empty($object['published'])) {
1354                         $published = $object['published'];
1355                 } elseif (!empty($child['published'])) {
1356                         $published = $child['published'];
1357                 } else {
1358                         $published = DateTimeFormat::utcNow();
1359                 }
1360
1361                 $activity = [];
1362                 $activity['@context'] = $object['@context'] ?? ActivityPub::CONTEXT;
1363                 unset($object['@context']);
1364                 $activity['id'] = $object['id'];
1365                 $activity['to'] = $object['to'] ?? [];
1366                 $activity['cc'] = $object['cc'] ?? [];
1367                 $activity['actor'] = $actor;
1368                 $activity['object'] = $object;
1369                 $activity['published'] = $published;
1370                 $activity['type'] = 'Create';
1371
1372                 $ldactivity = JsonLD::compact($activity);
1373
1374                 $ldactivity['recursion-depth'] = !empty($child['recursion-depth']) ? $child['recursion-depth'] + 1 : 1;
1375
1376                 if (!empty($relay_actor)) {
1377                         $ldactivity['thread-completion'] = $ldactivity['from-relay'] = Contact::getIdForURL($relay_actor);
1378                         $ldactivity['completion-mode']   = Receiver::COMPLETION_RELAY;
1379                 } elseif (!empty($child['thread-completion'])) {
1380                         $ldactivity['thread-completion'] = $child['thread-completion'];
1381                         $ldactivity['completion-mode']   = $child['completion-mode'] ?? Receiver::COMPLETION_NONE;
1382                 } else {
1383                         $ldactivity['thread-completion'] = Contact::getIdForURL($actor);
1384                         $ldactivity['completion-mode']   = $completion;
1385                 }
1386
1387                 if (!empty($child['type'])) {
1388                         $ldactivity['thread-children-type'] = $child['type'];
1389                 }
1390
1391                 if (!empty($relay_actor) && !self::acceptIncomingMessage($ldactivity, $object['id'])) {
1392                         return '';
1393                 }
1394
1395                 if (($completion == Receiver::COMPLETION_RELAY) && Queue::exists($url, 'as:Create')) {
1396                         Logger::notice('Activity has already been queued.', ['url' => $url, 'object' => $activity['id']]);
1397                 } elseif (ActivityPub\Receiver::processActivity($ldactivity, json_encode($activity), $uid, true, false, $signer, '', $completion)) {
1398                         Logger::notice('Activity had been fetched and processed.', ['url' => $url, 'entry' => $child['entry-id'] ?? 0, 'completion' => $completion, 'object' => $activity['id']]);
1399                 } else {
1400                         Logger::notice('Activity had been fetched and will be processed later.', ['url' => $url, 'entry' => $child['entry-id'] ?? 0, 'completion' => $completion, 'object' => $activity['id']]);
1401                 }
1402
1403                 return $activity['id'];
1404         }
1405
1406         /**
1407          * Test if incoming relay messages should be accepted
1408          *
1409          * @param array $activity activity array
1410          * @param string $id      object ID
1411          * @return boolean true if message is accepted
1412          */
1413         private static function acceptIncomingMessage(array $activity, string $id): bool
1414         {
1415                 if (empty($activity['as:object'])) {
1416                         Logger::info('No object field in activity - accepted', ['id' => $id]);
1417                         return true;
1418                 }
1419
1420                 $replyto = JsonLD::fetchElement($activity['as:object'], 'as:inReplyTo', '@id');
1421                 $uriid = ItemURI::getIdByURI($replyto ?? '');
1422                 if (Post::exists(['uri-id' => $uriid])) {
1423                         Logger::info('Post is a reply to an existing post - accepted', ['id' => $id, 'uri-id' => $uriid, 'replyto' => $replyto]);
1424                         return true;
1425                 }
1426
1427                 $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
1428                 $authorid = Contact::getIdForURL($attributed_to);
1429
1430                 $body = HTML::toBBCode(JsonLD::fetchElement($activity['as:object'], 'as:content', '@value') ?? '');
1431
1432                 $messageTags = [];
1433                 $tags = Receiver::processTags(JsonLD::fetchElementArray($activity['as:object'], 'as:tag') ?? []);
1434                 if (!empty($tags)) {
1435                         foreach ($tags as $tag) {
1436                                 if ($tag['type'] != 'Hashtag') {
1437                                         continue;
1438                                 }
1439                                 $messageTags[] = ltrim(mb_strtolower($tag['name']), '#');
1440                         }
1441                 }
1442
1443                 return Relay::isSolicitedPost($messageTags, $body, $authorid, $id, Protocol::ACTIVITYPUB);
1444         }
1445
1446         /**
1447          * perform a "follow" request
1448          *
1449          * @param array $activity
1450          * @return void
1451          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1452          * @throws \ImagickException
1453          */
1454         public static function followUser(array $activity)
1455         {
1456                 $uid = User::getIdForURL($activity['object_id']);
1457                 if (empty($uid)) {
1458                         Queue::remove($activity);
1459                         return;
1460                 }
1461
1462                 $owner = User::getOwnerDataById($uid);
1463                 if (empty($owner)) {
1464                         return;
1465                 }
1466
1467                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1468                 if (!empty($cid)) {
1469                         self::switchContact($cid);
1470                         Contact::update(['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
1471                 }
1472
1473                 $item = [
1474                         'author-id' => Contact::getIdForURL($activity['actor']),
1475                         'author-link' => $activity['actor'],
1476                 ];
1477
1478                 // Ensure that the contact has got the right network type
1479                 self::switchContact($item['author-id']);
1480
1481                 $result = Contact::addRelationship($owner, [], $item, false, $activity['content'] ?? '');
1482                 if ($result === true) {
1483                         ActivityPub\Transmitter::sendContactAccept($item['author-link'], $activity['id'], $owner['uid']);
1484                 }
1485
1486                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1487                 if (empty($cid)) {
1488                         return;
1489                 }
1490
1491                 if ($result && DI::config()->get('system', 'transmit_pending_events') && ($owner['contact-type'] == Contact::TYPE_COMMUNITY)) {
1492                         self::transmitPendingEvents($cid, $owner['uid']);
1493                 }
1494
1495                 if (empty($contact)) {
1496                         Contact::update(['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
1497                 }
1498                 Logger::notice('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
1499                 Queue::remove($activity);
1500         }
1501
1502         /**
1503          * Transmit pending events to the new follower
1504          *
1505          * @param integer $cid Contact id
1506          * @param integer $uid User id
1507          * @return void
1508          */
1509         private static function transmitPendingEvents(int $cid, int $uid)
1510         {
1511                 $account = DBA::selectFirst('account-user-view', ['ap-inbox', 'ap-sharedinbox'], ['id' => $cid]);
1512                 $inbox = $account['ap-sharedinbox'] ?: $account['ap-inbox'];
1513
1514                 $events = DBA::select('event', ['id'], ["`uid` = ? AND `start` > ? AND `type` != ?", $uid, DateTimeFormat::utcNow(), 'birthday']);
1515                 while ($event = DBA::fetch($events)) {
1516                         $post = Post::selectFirst(['id', 'uri-id', 'created'], ['event-id' => $event['id']]);
1517                         if (empty($post)) {
1518                                 continue;
1519                         }
1520                         if (DI::config()->get('system', 'bulk_delivery')) {
1521                                 Post\Delivery::add($post['uri-id'], $uid, $inbox, $post['created'], Delivery::POST, [$cid]);
1522                                 Worker::add(PRIORITY_HIGH, 'APDelivery', '', 0, $inbox, 0);
1523                         } else {
1524                                 Worker::add(PRIORITY_HIGH, 'APDelivery', Delivery::POST, $post['id'], $inbox, $uid, [$cid], $post['uri-id']);
1525                         }
1526                 }
1527         }
1528
1529         /**
1530          * Update the given profile
1531          *
1532          * @param array $activity
1533          * @throws \Exception
1534          */
1535         public static function updatePerson(array $activity)
1536         {
1537                 if (empty($activity['object_id'])) {
1538                         return;
1539                 }
1540
1541                 Logger::info('Updating profile', ['object' => $activity['object_id']]);
1542                 Contact::updateFromProbeByURL($activity['object_id']);
1543                 Queue::remove($activity);
1544         }
1545
1546         /**
1547          * Delete the given profile
1548          *
1549          * @param array $activity
1550          * @return void
1551          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1552          */
1553         public static function deletePerson(array $activity)
1554         {
1555                 if (empty($activity['object_id']) || empty($activity['actor'])) {
1556                         Logger::info('Empty object id or actor.');
1557                         return;
1558                 }
1559
1560                 if ($activity['object_id'] != $activity['actor']) {
1561                         Logger::info('Object id does not match actor.');
1562                         return;
1563                 }
1564
1565                 $contacts = DBA::select('contact', ['id'], ['nurl' => Strings::normaliseLink($activity['object_id'])]);
1566                 while ($contact = DBA::fetch($contacts)) {
1567                         Contact::remove($contact['id']);
1568                 }
1569                 DBA::close($contacts);
1570
1571                 Logger::info('Deleted contact', ['object' => $activity['object_id']]);
1572                 Queue::remove($activity);
1573         }
1574
1575         /**
1576          * Blocks the user by the contact
1577          *
1578          * @param array $activity
1579          * @return void
1580          * @throws \Exception
1581          */
1582         public static function blockAccount(array $activity)
1583         {
1584                 $cid = Contact::getIdForURL($activity['actor']);
1585                 if (empty($cid)) {
1586                         return;
1587                 }
1588
1589                 $uid = User::getIdForURL($activity['object_id']);
1590                 if (empty($uid)) {
1591                         return;
1592                 }
1593
1594                 Contact\User::setIsBlocked($cid, $uid, true);
1595
1596                 Logger::info('Contact blocked user', ['contact' => $cid, 'user' => $uid]);
1597                 Queue::remove($activity);
1598         }
1599
1600         /**
1601          * Unblocks the user by the contact
1602          *
1603          * @param array $activity
1604          * @return void
1605          * @throws \Exception
1606          */
1607         public static function unblockAccount(array $activity)
1608         {
1609                 $cid = Contact::getIdForURL($activity['actor']);
1610                 if (empty($cid)) {
1611                         return;
1612                 }
1613
1614                 $uid = User::getIdForURL($activity['object_object']);
1615                 if (empty($uid)) {
1616                         return;
1617                 }
1618
1619                 Contact\User::setIsBlocked($cid, $uid, false);
1620
1621                 Logger::info('Contact unblocked user', ['contact' => $cid, 'user' => $uid]);
1622                 Queue::remove($activity);
1623         }
1624
1625         /**
1626          * Accept a follow request
1627          *
1628          * @param array $activity
1629          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1630          * @throws \ImagickException
1631          */
1632         public static function acceptFollowUser(array $activity)
1633         {
1634                 $uid = User::getIdForURL($activity['object_actor']);
1635                 if (empty($uid)) {
1636                         return;
1637                 }
1638
1639                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1640                 if (empty($cid)) {
1641                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1642                         return;
1643                 }
1644
1645                 self::switchContact($cid);
1646
1647                 $fields = ['pending' => false];
1648
1649                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
1650                 if ($contact['rel'] == Contact::FOLLOWER) {
1651                         $fields['rel'] = Contact::FRIEND;
1652                 }
1653
1654                 $condition = ['id' => $cid];
1655                 Contact::update($fields, $condition);
1656                 Logger::info('Accept contact request', ['contact' => $cid, 'user' => $uid]);
1657                 Queue::remove($activity);
1658         }
1659
1660         /**
1661          * Reject a follow request
1662          *
1663          * @param array $activity
1664          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1665          * @throws \ImagickException
1666          */
1667         public static function rejectFollowUser(array $activity)
1668         {
1669                 $uid = User::getIdForURL($activity['object_actor']);
1670                 if (empty($uid)) {
1671                         return;
1672                 }
1673
1674                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1675                 if (empty($cid)) {
1676                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1677                         return;
1678                 }
1679
1680                 self::switchContact($cid);
1681
1682                 $contact = Contact::getById($cid, ['rel']);
1683                 if ($contact['rel'] == Contact::SHARING) {
1684                         Contact::remove($cid);
1685                         Logger::info('Rejected contact request - contact removed', ['contact' => $cid, 'user' => $uid]);
1686                 } elseif ($contact['rel'] == Contact::FRIEND) {
1687                         Contact::update(['rel' => Contact::FOLLOWER], ['id' => $cid]);
1688                 } else {
1689                         Logger::info('Rejected contact request', ['contact' => $cid, 'user' => $uid]);
1690                 }
1691                 Queue::remove($activity);
1692         }
1693
1694         /**
1695          * Undo activity like "like" or "dislike"
1696          *
1697          * @param array $activity
1698          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1699          * @throws \ImagickException
1700          */
1701         public static function undoActivity(array $activity)
1702         {
1703                 if (empty($activity['object_id'])) {
1704                         return;
1705                 }
1706
1707                 if (empty($activity['object_actor'])) {
1708                         return;
1709                 }
1710
1711                 $author_id = Contact::getIdForURL($activity['object_actor']);
1712                 if (empty($author_id)) {
1713                         return;
1714                 }
1715
1716                 Item::markForDeletion(['uri' => $activity['object_id'], 'author-id' => $author_id, 'gravity' => GRAVITY_ACTIVITY]);
1717                 Queue::remove($activity);
1718         }
1719
1720         /**
1721          * Activity to remove a follower
1722          *
1723          * @param array $activity
1724          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1725          * @throws \ImagickException
1726          */
1727         public static function undoFollowUser(array $activity)
1728         {
1729                 $uid = User::getIdForURL($activity['object_object']);
1730                 if (empty($uid)) {
1731                         return;
1732                 }
1733
1734                 $owner = User::getOwnerDataById($uid);
1735                 if (empty($owner)) {
1736                         return;
1737                 }
1738
1739                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1740                 if (empty($cid)) {
1741                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1742                         return;
1743                 }
1744
1745                 self::switchContact($cid);
1746
1747                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1748                 if (!DBA::isResult($contact)) {
1749                         return;
1750                 }
1751
1752                 Contact::removeFollower($contact);
1753                 Logger::info('Undo following request', ['contact' => $cid, 'user' => $uid]);
1754                 Queue::remove($activity);
1755         }
1756
1757         /**
1758          * Switches a contact to AP if needed
1759          *
1760          * @param integer $cid Contact ID
1761          * @return void
1762          * @throws \Exception
1763          */
1764         private static function switchContact(int $cid)
1765         {
1766                 $contact = DBA::selectFirst('contact', ['network', 'url'], ['id' => $cid]);
1767                 if (!DBA::isResult($contact) || in_array($contact['network'], [Protocol::ACTIVITYPUB, Protocol::DFRN]) || Contact::isLocal($contact['url'])) {
1768                         return;
1769                 }
1770
1771                 Logger::info('Change existing contact', ['cid' => $cid, 'previous' => $contact['network']]);
1772                 Contact::updateFromProbe($cid);
1773         }
1774
1775         /**
1776          * Collects implicit mentions like:
1777          * - the author of the parent item
1778          * - all the mentioned conversants in the parent item
1779          *
1780          * @param array $parent Item array with at least ['id', 'author-link', 'alias']
1781          * @return array
1782          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1783          */
1784         private static function getImplicitMentionList(array $parent): array
1785         {
1786                 $parent_terms = Tag::getByURIId($parent['uri-id'], [Tag::MENTION, Tag::IMPLICIT_MENTION, Tag::EXCLUSIVE_MENTION]);
1787
1788                 $parent_author = Contact::getByURL($parent['author-link'], false, ['url', 'nurl', 'alias']);
1789
1790                 $implicit_mentions = [];
1791                 if (empty($parent_author['url'])) {
1792                         Logger::notice('Author public contact unknown.', ['author-link' => $parent['author-link'], 'parent-id' => $parent['id']]);
1793                 } else {
1794                         $implicit_mentions[] = $parent_author['url'];
1795                         $implicit_mentions[] = $parent_author['nurl'];
1796                         $implicit_mentions[] = $parent_author['alias'];
1797                 }
1798
1799                 if (!empty($parent['alias'])) {
1800                         $implicit_mentions[] = $parent['alias'];
1801                 }
1802
1803                 foreach ($parent_terms as $term) {
1804                         $contact = Contact::getByURL($term['url'], false, ['url', 'nurl', 'alias']);
1805                         if (!empty($contact['url'])) {
1806                                 $implicit_mentions[] = $contact['url'];
1807                                 $implicit_mentions[] = $contact['nurl'];
1808                                 $implicit_mentions[] = $contact['alias'];
1809                         }
1810                 }
1811
1812                 return $implicit_mentions;
1813         }
1814
1815         /**
1816          * Strips from the body prepended implicit mentions
1817          *
1818          * @param string $body
1819          * @param array $parent
1820          * @return string
1821          */
1822         private static function removeImplicitMentionsFromBody(string $body, array $parent): string
1823         {
1824                 if (DI::config()->get('system', 'disable_implicit_mentions')) {
1825                         return $body;
1826                 }
1827
1828                 $potential_mentions = self::getImplicitMentionList($parent);
1829
1830                 $kept_mentions = [];
1831
1832                 // Extract one prepended mention at a time from the body
1833                 while(preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $body, $matches)) {
1834                         if (!in_array($matches[2], $potential_mentions)) {
1835                                 $kept_mentions[] = $matches[1];
1836                         }
1837
1838                         $body = $matches[3];
1839                 }
1840
1841                 // Re-appending the kept mentions to the body after extraction
1842                 $kept_mentions[] = $body;
1843
1844                 return implode('', $kept_mentions);
1845         }
1846
1847         /**
1848          * Adds links to string mentions
1849          *
1850          * @param string $body
1851          * @param array  $tags
1852          * @return string
1853          */
1854         protected static function addMentionLinks(string $body, array $tags): string
1855         {
1856                 // This prevents links to be added again to Pleroma-style mention links
1857                 $body = self::normalizeMentionLinks($body);
1858
1859                 $body = BBCode::performWithEscapedTags($body, ['url'], function ($body) use ($tags) {
1860                         foreach ($tags as $tag) {
1861                                 if (empty($tag['name']) || empty($tag['type']) || empty($tag['href']) || !in_array($tag['type'], ['Mention', 'Hashtag'])) {
1862                                         continue;
1863                                 }
1864
1865                                 $hash = substr($tag['name'], 0, 1);
1866                                 $name = substr($tag['name'], 1);
1867                                 if (!in_array($hash, Tag::TAG_CHARACTER)) {
1868                                         $hash = '';
1869                                         $name = $tag['name'];
1870                                 }
1871
1872                                 $body = str_replace($tag['name'], $hash . '[url=' . $tag['href'] . ']' . $name . '[/url]', $body);
1873                         }
1874
1875                         return $body;
1876                 });
1877
1878                 return $body;
1879         }
1880 }