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         /**
  64          * Add an object id to the list of processed ids
  65          *
  66          * @param string $id
  67          *
  68          * @return void
  69          */
  70         private static function addActivityId(string $id)
  71         {
  72                 DBA::delete('processed-activity', ["`received` < ?", DateTimeFormat::utc('now - 5 minutes')]);
  73                 DBA::insert('processed-activity', ['object-id' => $id, 'received' => DateTimeFormat::utcNow()]);
  74         }
  75
  76         /**
  77          * Checks if the given object id has just been processed
  78          *
  79          * @param string $id
  80          *
  81          * @return boolean
  82          */
  83         private static function isProcessed(string $id): bool
  84         {
  85                 return DBA::exists('processed-activity', ['object-id' => $id]);
  86         }
  87
  88         /**
  89          * Extracts the tag character (#, @, !) from mention links
  90          *
  91          * @param string $body
  92          * @return string
  93          */
  94         protected static function normalizeMentionLinks(string $body): string
  95         {
  96                 return preg_replace('%\[url=([^\[\]]*)]([#@!])(.*?)\[/url]%ism', '$2[url=$1]$3[/url]', $body);
  97         }
  98
  99         /**
 100          * Convert the language array into a language JSON
 101          *
 102          * @param array $languages
 103          * @return string language JSON
 104          */
 105         private static function processLanguages(array $languages): string
 106         {
 107                 $codes = array_keys($languages);
 108                 $lang = [];
 109                 foreach ($codes as $code) {
 110                         $lang[$code] = 1;
 111                 }
 112
 113                 if (empty($lang)) {
 114                         return '';
 115                 }
 116
 117                 return json_encode($lang);
 118         }
 119         /**
 120          * Replaces emojis in the body
 121          *
 122          * @param int $uri_id
 123          * @param string $body
 124          * @param array $emojis
 125          *
 126          * @return string with replaced emojis
 127          */
 128         private static function replaceEmojis(int $uri_id, string $body, array $emojis): string
 129         {
 130                 $body = strtr($body,
 131                         array_combine(
 132                                 array_column($emojis, 'name'),
 133                                 array_map(function ($emoji) {
 134                                         return '[emoji=' . $emoji['href'] . ']' . $emoji['name'] . '[/emoji]';
 135                                 }, $emojis)
 136                         )
 137                 );
 138
 139                 // We store the emoji here to be able to avoid storing it in the media
 140                 foreach ($emojis as $emoji) {
 141                         Post\Link::getByLink($uri_id, $emoji['href']);
 142                 }
 143                 return $body;
 144         }
 145
 146         /**
 147          * Store attached media files in the post-media table
 148          *
 149          * @param int $uriid
 150          * @param array $attachment
 151          * @return void
 152          */
 153         private static function storeAttachmentAsMedia(int $uriid, array $attachment)
 154         {
 155                 if (empty($attachment['url'])) {
 156                         return;
 157                 }
 158
 159                 $data = ['uri-id' => $uriid];
 160                 $data['type'] = Post\Media::UNKNOWN;
 161                 $data['url'] = $attachment['url'];
 162                 $data['mimetype'] = $attachment['mediaType'] ?? null;
 163                 $data['height'] = $attachment['height'] ?? null;
 164                 $data['width'] = $attachment['width'] ?? null;
 165                 $data['size'] = $attachment['size'] ?? null;
 166                 $data['preview'] = $attachment['image'] ?? null;
 167                 $data['description'] = $attachment['name'] ?? null;
 168
 169                 Post\Media::insert($data);
 170         }
 171
 172         /**
 173          * Stire attachment data
 174          *
 175          * @param array   $activity
 176          * @param array   $item
 177          */
 178         private static function storeAttachments(array $activity, array $item)
 179         {
 180                 if (empty($activity['attachments'])) {
 181                         return;
 182                 }
 183
 184                 foreach ($activity['attachments'] as $attach) {
 185                         self::storeAttachmentAsMedia($item['uri-id'], $attach);
 186                 }
 187         }
 188
 189         /**
 190          * Store attachment data
 191          *
 192          * @param array   $activity
 193          * @param array   $item
 194          */
 195         private static function storeQuestion(array $activity, array $item)
 196         {
 197                 if (empty($activity['question'])) {
 198                         return;
 199                 }
 200                 $question = ['multiple' => $activity['question']['multiple']];
 201
 202                 if (!empty($activity['question']['voters'])) {
 203                         $question['voters'] = $activity['question']['voters'];
 204                 }
 205
 206                 if (!empty($activity['question']['end-time'])) {
 207                         $question['end-time'] = DateTimeFormat::utc($activity['question']['end-time']);
 208                 }
 209
 210                 Post\Question::update($item['uri-id'], $question);
 211
 212                 foreach ($activity['question']['options'] as $key => $option) {
 213                         $option = ['name' => $option['name'], 'replies' => $option['replies']];
 214                         Post\QuestionOption::update($item['uri-id'], $key, $option);
 215                 }
 216
 217                 Logger::debug('Storing incoming question', ['type' => $activity['type'], 'uri-id' => $item['uri-id'], 'question' => $activity['question']]);
 218         }
 219
 220         /**
 221          * Updates a message
 222          *
 223          * @param array      $activity   Activity array
 224          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 225          * @throws \ImagickException
 226          */
 227         public static function updateItem(array $activity)
 228         {
 229                 $item = Post::selectFirst(['uri', 'uri-id', 'thr-parent', 'gravity', 'post-type', 'private'], ['uri' => $activity['id']]);
 230                 if (!DBA::isResult($item)) {
 231                         Logger::warning('No existing item, item will be created', ['uri' => $activity['id']]);
 232                         $item = self::createItem($activity, false);
 233                         if (empty($item)) {
 234                                 Queue::remove($activity);
 235                                 return;
 236                         }
 237
 238                         self::postItem($activity, $item);
 239                         return;
 240                 }
 241
 242                 $item['changed'] = DateTimeFormat::utcNow();
 243                 $item['edited'] = DateTimeFormat::utc($activity['updated']);
 244
 245                 $item = self::processContent($activity, $item);
 246                 if (empty($item)) {
 247                         Queue::remove($activity);
 248                         return;
 249                 }
 250
 251                 self::storeAttachments($activity, $item);
 252                 self::storeQuestion($activity, $item);
 253
 254                 Post\History::add($item['uri-id'], $item);
 255                 Item::update($item, ['uri' => $activity['id']]);
 256
 257                 Queue::remove($activity);
 258
 259                 if ($activity['object_type'] == 'as:Event') {
 260                         $posts = Post::select(['event-id', 'uid'], ["`uri` = ? AND `event-id` > ?", $activity['id'], 0]);
 261                         while ($post = DBA::fetch($posts)) {
 262                                 self::updateEvent($post['event-id'], $activity);
 263                         }
 264                 }
 265         }
 266
 267         /**
 268          * Update an existing event
 269          *
 270          * @param int $event_id
 271          * @param array $activity
 272          */
 273         private static function updateEvent(int $event_id, array $activity)
 274         {
 275                 $event = DBA::selectFirst('event', [], ['id' => $event_id]);
 276
 277                 $event['edited']   = DateTimeFormat::utc($activity['updated']);
 278                 $event['summary']  = HTML::toBBCode($activity['name']);
 279                 $event['desc']     = HTML::toBBCode($activity['content']);
 280                 if (!empty($activity['start-time'])) {
 281                         $event['start']  = DateTimeFormat::utc($activity['start-time']);
 282                 }
 283                 if (!empty($activity['end-time'])) {
 284                         $event['finish'] = DateTimeFormat::utc($activity['end-time']);
 285                 }
 286                 $event['nofinish'] = empty($event['finish']);
 287                 $event['location'] = $activity['location'];
 288
 289                 Logger::info('Updating event', ['uri' => $activity['id'], 'id' => $event_id]);
 290                 Event::store($event);
 291         }
 292
 293         /**
 294          * Prepares data for a message
 295          *
 296          * @param array $activity      Activity array
 297          * @param bool  $fetch_parents
 298          *
 299          * @return array Internal item
 300          *
 301          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 302          * @throws \ImagickException
 303          */
 304         public static function createItem(array $activity, bool $fetch_parents): array
 305         {
 306                 if (self::isProcessed($activity['id']) && !Post::exists(['uri' => $activity['id']])) {
 307                         Logger::info('Id is already processed', ['id' => $activity['id']]);
 308                         return [];
 309                 }
 310
 311                 self::addActivityId($activity['id']);
 312
 313                 $item = [];
 314                 $item['verb'] = Activity::POST;
 315                 $item['thr-parent'] = $activity['reply-to-id'];
 316
 317                 if ($activity['reply-to-id'] == $activity['id']) {
 318                         $item['gravity'] = GRAVITY_PARENT;
 319                         $item['object-type'] = Activity\ObjectType::NOTE;
 320                 } else {
 321                         $item['gravity'] = GRAVITY_COMMENT;
 322                         $item['object-type'] = Activity\ObjectType::COMMENT;
 323                 }
 324
 325                 if (!empty($activity['conversation'])) {
 326                         $item['conversation'] = $activity['conversation'];
 327                 } elseif (!empty($activity['context'])) {
 328                         $item['conversation'] = $activity['context'];
 329                 }
 330
 331                 if (!empty($item['conversation'])) {
 332                         $conversation = Post::selectFirstThread(['uri'], ['conversation' => $item['conversation']]);
 333                         if (!empty($conversation)) {
 334                                 Logger::debug('Got conversation', ['conversation' => $item['conversation'], 'parent' => $conversation]);
 335                                 $item['parent-uri'] = $conversation['uri'];
 336                         }
 337                 } else {
 338                         $conversation = [];
 339                 }
 340
 341                 Logger::debug('Create Item', ['id' => $activity['id'], 'conversation' => $item['conversation'] ?? '']);
 342                 if (empty($activity['author']) && empty($activity['actor'])) {
 343                         Logger::notice('Missing author and actor. We quit here.', ['activity' => $activity]);
 344                         Queue::remove($activity);
 345                         return [];
 346                 }
 347
 348                 if (!in_array(0, $activity['receiver']) || !DI::config()->get('system', 'fetch_parents')) {
 349                         $fetch_parents = false;
 350                 }
 351
 352                 if ($fetch_parents && empty($activity['directmessage']) && ($activity['id'] != $activity['reply-to-id']) && !Post::exists(['uri' => $activity['reply-to-id']])) {
 353                         $result = self::fetchParent($activity);
 354                         if (!empty($result)) {
 355                                 if (($item['thr-parent'] != $result) && Post::exists(['uri' => $result])) {
 356                                         $item['thr-parent'] = $result;
 357                                 }
 358                         } elseif (empty($conversation)) {
 359                                 return [];
 360                         }
 361                 }
 362
 363                 $item['diaspora_signed_text'] = $activity['diaspora:comment'] ?? '';
 364
 365                 if (empty($conversation) && empty($activity['directmessage']) && ($item['gravity'] != GRAVITY_PARENT) && !Post::exists(['uri' => $item['thr-parent']])) {
 366                         Logger::info('Parent not found, message will be discarded.', ['thr-parent' => $item['thr-parent']]);
 367                         if (!$fetch_parents) {
 368                                 Queue::remove($activity);
 369                         }
 370                         return [];
 371                 }
 372
 373                 $item['network'] = Protocol::ACTIVITYPUB;
 374                 $item['author-link'] = $activity['author'];
 375                 $item['author-id'] = Contact::getIdForURL($activity['author']);
 376                 $item['owner-link'] = $activity['actor'];
 377                 $item['owner-id'] = Contact::getIdForURL($activity['actor']);
 378
 379                 if (in_array(0, $activity['receiver']) && !empty($activity['unlisted'])) {
 380                         $item['private'] = Item::UNLISTED;
 381                 } elseif (in_array(0, $activity['receiver'])) {
 382                         $item['private'] = Item::PUBLIC;
 383                 } else {
 384                         $item['private'] = Item::PRIVATE;
 385                 }
 386
 387                 if (!empty($activity['raw'])) {
 388                         $item['source'] = $activity['raw'];
 389                 }
 390
 391                 $item['protocol'] = Conversation::PARCEL_ACTIVITYPUB;
 392
 393                 if (isset($activity['push'])) {
 394                         $item['direction'] = $activity['push'] ? Conversation::PUSH : Conversation::PULL;
 395                 }
 396
 397                 if (!empty($activity['from-relay'])) {
 398                         $item['direction'] = Conversation::RELAY;
 399                 }
 400
 401                 if ($activity['object_type'] == 'as:Article') {
 402                         $item['post-type'] = Item::PT_ARTICLE;
 403                 } elseif ($activity['object_type'] == 'as:Audio') {
 404                         $item['post-type'] = Item::PT_AUDIO;
 405                 } elseif ($activity['object_type'] == 'as:Document') {
 406                         $item['post-type'] = Item::PT_DOCUMENT;
 407                 } elseif ($activity['object_type'] == 'as:Event') {
 408                         $item['post-type'] = Item::PT_EVENT;
 409                 } elseif ($activity['object_type'] == 'as:Image') {
 410                         $item['post-type'] = Item::PT_IMAGE;
 411                 } elseif ($activity['object_type'] == 'as:Page') {
 412                         $item['post-type'] = Item::PT_PAGE;
 413                 } elseif ($activity['object_type'] == 'as:Question') {
 414                         $item['post-type'] = Item::PT_POLL;
 415                 } elseif ($activity['object_type'] == 'as:Video') {
 416                         $item['post-type'] = Item::PT_VIDEO;
 417                 } else {
 418                         $item['post-type'] = Item::PT_NOTE;
 419                 }
 420
 421                 $item['isForum'] = false;
 422
 423                 if (!empty($activity['thread-completion'])) {
 424                         if ($activity['thread-completion'] != $item['owner-id']) {
 425                                 $actor = Contact::getById($activity['thread-completion'], ['url']);
 426                                 $item['causer-link'] = $actor['url'];
 427                                 $item['causer-id'] = $activity['thread-completion'];
 428                                 Logger::info('Use inherited actor as causer.', ['id' => $item['owner-id'], 'activity' => $activity['thread-completion'], 'owner' => $item['owner-link'], 'actor' => $actor['url']]);
 429                         } else {
 430                                 // Store the original actor in the "causer" fields to enable the check for ignored or blocked contacts
 431                                 $item['causer-link'] = $item['owner-link'];
 432                                 $item['causer-id']   = $item['owner-id'];
 433                                 Logger::info('Use actor as causer.', ['id' => $item['owner-id'], 'actor' => $item['owner-link']]);
 434                         }
 435
 436                         $item['owner-link'] = $item['author-link'];
 437                         $item['owner-id'] = $item['author-id'];
 438                 } else {
 439                         $actor = APContact::getByURL($item['owner-link'], false);
 440                         $item['isForum'] = ($actor['type'] == 'Group');
 441                 }
 442
 443                 $item['uri'] = $activity['id'];
 444
 445                 if (empty($activity['published']) || empty($activity['updated'])) {
 446                         DI::logger()->notice('published or updated keys are empty for activity', ['activity' => $activity, 'callstack' => System::callstack(10)]);
 447                 }
 448
 449                 $item['created'] = DateTimeFormat::utc($activity['published'] ?? 'now');
 450                 $item['edited'] = DateTimeFormat::utc($activity['updated'] ?? 'now');
 451                 $guid = $activity['sc:identifier'] ?: self::getGUIDByURL($item['uri']);
 452                 $item['guid'] = $activity['diaspora:guid'] ?: $guid;
 453
 454                 $item['uri-id'] = ItemURI::insert(['uri' => $item['uri'], 'guid' => $item['guid']]);
 455                 if (empty($item['uri-id'])) {
 456                         Logger::warning('Unable to get a uri-id for an item uri', ['uri' => $item['uri'], 'guid' => $item['guid']]);
 457                         return [];
 458                 }
 459
 460                 $item = self::processContent($activity, $item);
 461                 if (empty($item)) {
 462                         Logger::info('Message was not processed');
 463                         Queue::remove($activity);
 464                         return [];
 465                 }
 466
 467                 $item['plink'] = $activity['alternate-url'] ?? $item['uri'];
 468
 469                 self::storeAttachments($activity, $item);
 470                 self::storeQuestion($activity, $item);
 471
 472                 // We received the post via AP, so we set the protocol of the server to AP
 473                 $contact = Contact::getById($item['author-id'], ['gsid']);
 474                 if (!empty($contact['gsid'])) {
 475                         GServer::setProtocol($contact['gsid'], Post\DeliveryData::ACTIVITYPUB);
 476                 }
 477
 478                 if ($item['author-id'] != $item['owner-id']) {
 479                         $contact = Contact::getById($item['owner-id'], ['gsid']);
 480                         if (!empty($contact['gsid'])) {
 481                                 GServer::setProtocol($contact['gsid'], Post\DeliveryData::ACTIVITYPUB);
 482                         }
 483                 }
 484
 485                 return $item;
 486         }
 487
 488         /**
 489          * Fetch and process parent posts for the given activity
 490          *
 491          * @param array $activity
 492          *
 493          * @return string
 494          */
 495         private static function fetchParent(array $activity): string
 496         {
 497                 $recursion_depth = $activity['recursion-depth'] ?? 0;
 498
 499                 if ($recursion_depth < DI::config()->get('system', 'max_recursion_depth')) {
 500                         Logger::notice('Parent not found. Try to refetch it.', ['parent' => $activity['reply-to-id'], 'recursion-depth' => $recursion_depth]);
 501                         $result = self::fetchMissingActivity($activity['reply-to-id'], $activity, '', Receiver::COMPLETION_AUTO);
 502                         if (empty($result) && self::isActivityGone($activity['reply-to-id'])) {
 503                                 Logger::notice('The activity is gone, the queue entry will be deleted', ['parent' => $activity['reply-to-id']]);
 504                                 if (!empty($activity['entry-id'])) {
 505                                         Queue::deleteById($activity['entry-id']);
 506                                 }
 507                                 return '';
 508                         } elseif (!empty($result)) {
 509                                 $exists = Post::exists(['uri' => [$result, $activity['reply-to-id']]]);
 510                                 if ($exists) {
 511                                         Logger::notice('The activity has been fetched and created.', ['parent' => $result]);
 512                                         return $result;
 513                                 } elseif (DI::config()->get('system', 'fetch_by_worker') || DI::config()->get('system', 'decoupled_receiver')) {
 514                                         Logger::notice('The activity has been fetched and will hopefully be created later.', ['parent' => $result]);
 515                                 } else {
 516                                         Logger::notice('The activity exists but has not been created, the queue entry will be deleted.', ['parent' => $result]);
 517                                         if (!empty($activity['entry-id'])) {
 518                                                 Queue::deleteById($activity['entry-id']);
 519                                         }
 520                                 }
 521                                 return '';
 522                         }
 523                         if (empty($result) && !DI::config()->get('system', 'fetch_by_worker')) {
 524                                 return '';
 525                         }
 526                 } elseif (self::isActivityGone($activity['reply-to-id'])) {
 527                         Logger::notice('The activity is gone. We will not spawn a worker. The queue entry will be deleted', ['parent' => $activity['reply-to-id']]);
 528                         if (!empty($activity['entry-id'])) {
 529                                 Queue::deleteById($activity['entry-id']);
 530                         }
 531                         return '';
 532                 } else {
 533                         Logger::notice('Recursion level is too high.', ['parent' => $activity['reply-to-id'], 'recursion-depth' => $recursion_depth]);
 534                 }
 535
 536                 if (Queue::hasWorker($activity['worker-id'] ?? 0)) {
 537                         Logger::notice('There is already a worker task to fetch the post.', ['id' => $activity['id'], 'parent' => $activity['reply-to-id']]);
 538                         return '';
 539                 }
 540
 541                 if (!Fetch::hasWorker($activity['reply-to-id'])) {
 542                         Logger::notice('Fetching is done by worker.', ['parent' => $activity['reply-to-id'], 'recursion-depth' => $recursion_depth]);
 543                         Fetch::add($activity['reply-to-id']);
 544                         $activity['recursion-depth'] = 0;
 545                         $wid = Worker::add(PRIORITY_HIGH, 'FetchMissingActivity', $activity['reply-to-id'], $activity, '', Receiver::COMPLETION_AUTO);
 546                         Fetch::setWorkerId($activity['reply-to-id'], $wid);
 547                 } else {
 548                         Logger::debug('Activity will already be fetched via a worker.', ['url' => $activity['reply-to-id']]);
 549                 }
 550
 551                 return '';
 552         }
 553
 554         /**
 555          * Check if a given activity is no longer available
 556          *
 557          * @param string $url
 558          *
 559          * @return boolean
 560          */
 561         public static function isActivityGone(string $url): bool
 562         {
 563                 $curlResult = HTTPSignature::fetchRaw($url, 0);
 564
 565                 if (Network::isUrlBlocked($url)) {
 566                         return true;
 567                 }
 568
 569                 // @todo To ensure that the remote system is working correctly, we can check if the "Content-Type" contains JSON
 570                 if (in_array($curlResult->getReturnCode(), [401, 404])) {
 571                         return true;
 572                 }
 573
 574                 if ($curlResult->isSuccess()) {
 575                         $object = json_decode($curlResult->getBody(), true);
 576                         if (!empty($object)) {
 577                                 $activity = JsonLD::compact($object);
 578                                 if (JsonLD::fetchElement($activity, '@type') == 'as:Tombstone') {
 579                                         return true;
 580                                 }
 581                         }
 582                 } elseif ($curlResult->getReturnCode() == 0) {
 583                         $host = parse_url($url, PHP_URL_HOST);
 584                         if (!(filter_var($host, FILTER_VALIDATE_IP) || @dns_get_record($host . '.', DNS_A + DNS_AAAA))) {
 585                                 return true;
 586                         }
 587                 }
 588
 589                 return false;
 590         }
 591         /**
 592          * Delete items
 593          *
 594          * @param array $activity
 595          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 596          * @throws \ImagickException
 597          */
 598         public static function deleteItem(array $activity)
 599         {
 600                 $owner = Contact::getIdForURL($activity['actor']);
 601
 602                 Logger::info('Deleting item', ['object' => $activity['object_id'], 'owner'  => $owner]);
 603                 Item::markForDeletion(['uri' => $activity['object_id'], 'owner-id' => $owner]);
 604                 Queue::remove($activity);
 605         }
 606
 607         /**
 608          * Prepare the item array for an activity
 609          *
 610          * @param array $activity Activity array
 611          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 612          * @throws \ImagickException
 613          */
 614         public static function addTag(array $activity)
 615         {
 616                 if (empty($activity['object_content']) || empty($activity['object_id'])) {
 617                         return;
 618                 }
 619
 620                 foreach ($activity['receiver'] as $receiver) {
 621                         $item = Post::selectFirst(['id', 'uri-id', 'origin', 'author-link'], ['uri' => $activity['target_id'], 'uid' => $receiver]);
 622                         if (!DBA::isResult($item)) {
 623                                 // We don't fetch missing content for this purpose
 624                                 continue;
 625                         }
 626
 627                         if (($item['author-link'] != $activity['actor']) && !$item['origin']) {
 628                                 Logger::info('Not origin, not from the author, skipping update', ['id' => $item['id'], 'author' => $item['author-link'], 'actor' => $activity['actor']]);
 629                                 continue;
 630                         }
 631
 632                         Tag::store($item['uri-id'], Tag::HASHTAG, $activity['object_content'], $activity['object_id']);
 633                         Logger::info('Tagged item', ['id' => $item['id'], 'tag' => $activity['object_content'], 'uri' => $activity['target_id'], 'actor' => $activity['actor']]);
 634                 }
 635         }
 636
 637         /**
 638          * Prepare the item array for an activity
 639          *
 640          * @param array      $activity   Activity array
 641          * @param string     $verb       Activity verb
 642          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 643          * @throws \ImagickException
 644          */
 645         public static function createActivity(array $activity, string $verb)
 646         {
 647                 $activity['reply-to-id'] = $activity['object_id'];
 648                 $item = self::createItem($activity, false);
 649                 if (empty($item)) {
 650                         return;
 651                 }
 652
 653                 $item['verb'] = $verb;
 654                 $item['thr-parent'] = $activity['object_id'];
 655                 $item['gravity'] = GRAVITY_ACTIVITY;
 656                 unset($item['post-type']);
 657                 $item['object-type'] = Activity\ObjectType::NOTE;
 658
 659                 if (!empty($activity['content'])) {
 660                         $item['body'] = HTML::toBBCode($activity['content']);
 661                 }
 662
 663                 $item['diaspora_signed_text'] = $activity['diaspora:like'] ?? '';
 664
 665                 self::postItem($activity, $item);
 666         }
 667
 668         /**
 669          * Fetch the Uri-Id of a post for the "featured" collection
 670          *
 671          * @param array $activity
 672          * @return null|int
 673          */
 674         private static function getUriIdForFeaturedCollection(array $activity)
 675         {
 676                 $actor = APContact::getByURL($activity['actor']);
 677                 if (empty($actor)) {
 678                         return null;
 679                 }
 680
 681                 // Refetch the account when the "featured" collection is missing.
 682                 // This can be removed in a future version (end of 2022 should be good).
 683                 if (empty($actor['featured'])) {
 684                         $actor = APContact::getByURL($activity['actor'], true);
 685                         if (empty($actor)) {
 686                                 return null;
 687                         }
 688                 }
 689
 690                 $parent = Post::selectFirst(['uri-id'], ['uri' => $activity['object_id']]);
 691                 if (empty($parent['uri-id'])) {
 692                         if (self::fetchMissingActivity($activity['object_id'], $activity, '', Receiver::COMPLETION_AUTO)) {
 693                                 $parent = Post::selectFirst(['uri-id'], ['uri' => $activity['object_id']]);
 694                         }
 695                 }
 696
 697                 if (!empty($parent['uri-id'])) {
 698                         return $parent['uri-id'];
 699                 }
 700
 701                 return null;
 702         }
 703
 704         /**
 705          * Add a post to the "Featured" collection
 706          *
 707          * @param array $activity
 708          */
 709         public static function addToFeaturedCollection(array $activity)
 710         {
 711                 $uriid = self::getUriIdForFeaturedCollection($activity);
 712                 if (empty($uriid)) {
 713                         return;
 714                 }
 715
 716                 Logger::debug('Add post to featured collection', ['uri-id' => $uriid]);
 717
 718                 Post\Collection::add($uriid, Post\Collection::FEATURED);
 719                 Queue::remove($activity);
 720         }
 721
 722         /**
 723          * Remove a post to the "Featured" collection
 724          *
 725          * @param array $activity
 726          */
 727         public static function removeFromFeaturedCollection(array $activity)
 728         {
 729                 $uriid = self::getUriIdForFeaturedCollection($activity);
 730                 if (empty($uriid)) {
 731                         return;
 732                 }
 733
 734                 Logger::debug('Remove post from featured collection', ['uri-id' => $uriid]);
 735
 736                 Post\Collection::remove($uriid, Post\Collection::FEATURED);
 737                 Queue::remove($activity);
 738         }
 739
 740         /**
 741          * Create an event
 742          *
 743          * @param array $activity Activity array
 744          * @param array $item
 745          *
 746          * @return int event id
 747          * @throws \Exception
 748          */
 749         public static function createEvent(array $activity, array $item): int
 750         {
 751                 $event['summary']   = HTML::toBBCode($activity['name'] ?: $activity['summary']);
 752                 $event['desc']      = HTML::toBBCode($activity['content']);
 753                 if (!empty($activity['start-time'])) {
 754                         $event['start']  = DateTimeFormat::utc($activity['start-time']);
 755                 }
 756                 if (!empty($activity['end-time'])) {
 757                         $event['finish'] = DateTimeFormat::utc($activity['end-time']);
 758                 }
 759                 $event['nofinish']  = empty($event['finish']);
 760                 $event['location']  = $activity['location'];
 761                 $event['cid']       = $item['contact-id'];
 762                 $event['uid']       = $item['uid'];
 763                 $event['uri']       = $item['uri'];
 764                 $event['edited']    = $item['edited'];
 765                 $event['private']   = $item['private'];
 766                 $event['guid']      = $item['guid'];
 767                 $event['plink']     = $item['plink'];
 768                 $event['network']   = $item['network'];
 769                 $event['protocol']  = $item['protocol'];
 770                 $event['direction'] = $item['direction'];
 771                 $event['source']    = $item['source'];
 772
 773                 $ev = DBA::selectFirst('event', ['id'], ['uri' => $item['uri'], 'uid' => $item['uid']]);
 774                 if (DBA::isResult($ev)) {
 775                         $event['id'] = $ev['id'];
 776                 }
 777
 778                 $event_id = Event::store($event);
 779
 780                 Logger::info('Event was stored', ['id' => $event_id]);
 781
 782                 return $event_id;
 783         }
 784
 785         /**
 786          * Process the content
 787          *
 788          * @param array $activity Activity array
 789          * @param array $item
 790          * @return array|bool Returns the item array or false if there was an unexpected occurrence
 791          * @throws \Exception
 792          */
 793         private static function processContent(array $activity, array $item)
 794         {
 795                 if (!empty($activity['mediatype']) && ($activity['mediatype'] == 'text/markdown')) {
 796                         $item['title'] = strip_tags($activity['name']);
 797                         $content = Markdown::toBBCode($activity['content']);
 798                 } elseif (!empty($activity['mediatype']) && ($activity['mediatype'] == 'text/bbcode')) {
 799                         $item['title'] = $activity['name'];
 800                         $content = $activity['content'];
 801                 } else {
 802                         // By default assume "text/html"
 803                         $item['title'] = HTML::toBBCode($activity['name'] ?? '');
 804                         $content = HTML::toBBCode($activity['content'] ?? '');
 805                 }
 806
 807                 $item['title'] = trim(BBCode::toPlaintext($item['title']));
 808
 809                 if (!empty($activity['languages'])) {
 810                         $item['language'] = self::processLanguages($activity['languages']);
 811                 }
 812
 813                 if (!empty($activity['emojis'])) {
 814                         $content = self::replaceEmojis($item['uri-id'], $content, $activity['emojis']);
 815                 }
 816
 817                 $content = self::addMentionLinks($content, $activity['tags']);
 818
 819                 if (!empty($activity['source'])) {
 820                         $item['body'] = $activity['source'];
 821                         $item['raw-body'] = $content;
 822                         $item['body'] = Item::improveSharedDataInBody($item);
 823                 } else {
 824                         $parent_uri = $item['parent-uri'] ?? $item['thr-parent'];
 825                         if (empty($activity['directmessage']) && ($parent_uri != $item['uri']) && ($item['gravity'] == GRAVITY_COMMENT)) {
 826                                 $parent = Post::selectFirst(['id', 'uri-id', 'private', 'author-link', 'alias'], ['uri' => $parent_uri]);
 827                                 if (!DBA::isResult($parent)) {
 828                                         Logger::warning('Unknown parent item.', ['uri' => $parent_uri]);
 829                                         return false;
 830                                 }
 831                                 if (!empty($activity['type']) && in_array($activity['type'], Receiver::CONTENT_TYPES) && ($item['private'] == Item::PRIVATE) && ($parent['private'] != Item::PRIVATE)) {
 832                                         Logger::warning('Item is private but the parent is not. Dropping.', ['item-uri' => $item['uri'], 'thr-parent' => $item['thr-parent']]);
 833                                         return false;
 834                                 }
 835
 836                                 $content = self::removeImplicitMentionsFromBody($content, $parent);
 837                         }
 838                         $item['content-warning'] = HTML::toBBCode($activity['summary'] ?? '');
 839                         $item['raw-body'] = $item['body'] = $content;
 840                 }
 841
 842                 self::storeFromBody($item);
 843                 self::storeTags($item['uri-id'], $activity['tags']);
 844
 845                 self::storeReceivers($item['uri-id'], $activity['receiver_urls'] ?? []);
 846
 847                 $item['location'] = $activity['location'];
 848
 849                 if (!empty($activity['latitude']) && !empty($activity['longitude'])) {
 850                         $item['coord'] = $activity['latitude'] . ' ' . $activity['longitude'];
 851                 }
 852
 853                 $item['app'] = $activity['generator'];
 854
 855                 return $item;
 856         }
 857
 858         /**
 859          * Store hashtags and mentions
 860          *
 861          * @param array $item
 862          */
 863         private static function storeFromBody(array $item)
 864         {
 865                 // Make sure to delete all existing tags (can happen when called via the update functionality)
 866                 DBA::delete('post-tag', ['uri-id' => $item['uri-id']]);
 867
 868                 Tag::storeFromBody($item['uri-id'], $item['body'], '@!');
 869         }
 870
 871         /**
 872          * Generate a GUID out of an URL of an ActivityPub post.
 873          *
 874          * @param string $url message URL
 875          * @return string with GUID
 876          */
 877         private static function getGUIDByURL(string $url): string
 878         {
 879                 $parsed = parse_url($url);
 880
 881                 $host_hash = hash('crc32', $parsed['host']);
 882
 883                 unset($parsed["scheme"]);
 884                 unset($parsed["host"]);
 885
 886                 $path = implode("/", $parsed);
 887
 888                 return $host_hash . '-'. hash('fnv164', $path) . '-'. hash('joaat', $path);
 889         }
 890
 891         /**
 892          * Checks if an incoming message is wanted
 893          *
 894          * @param array $activity
 895          * @param array $item
 896          * @return boolean Is the message wanted?
 897          */
 898         private static function isSolicitedMessage(array $activity, array $item): bool
 899         {
 900                 // The checks are split to improve the support when searching why a message was accepted.
 901                 if (count($activity['receiver']) != 1) {
 902                         // The message has more than one receiver, so it is wanted.
 903                         Logger::debug('Message has got several receivers - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 904                         return true;
 905                 }
 906
 907                 if ($item['private'] == Item::PRIVATE) {
 908                         // We only look at public posts here. Private posts are expected to be intentionally posted to the single receiver.
 909                         Logger::debug('Message is private - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 910                         return true;
 911                 }
 912
 913                 if (!empty($activity['from-relay'])) {
 914                         // We check relay posts at another place. When it arrived here, the message is already checked.
 915                         Logger::debug('Message is a relay post that is already checked - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 916                         return true;
 917                 }
 918
 919                 if (in_array($activity['completion-mode'] ?? Receiver::COMPLETION_NONE, [Receiver::COMPLETION_MANUAL, Receiver::COMPLETION_ANNOUCE])) {
 920                         // Manual completions and completions caused by reshares are allowed without any further checks.
 921                         Logger::debug('Message is in completion mode - accepted', ['mode' => $activity['completion-mode'], 'uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 922                         return true;
 923                 }
 924
 925                 if ($item['gravity'] != GRAVITY_PARENT) {
 926                         // We cannot reliably check at this point if a comment or activity belongs to an accepted post or needs to be fetched
 927                         // This can possibly be improved in the future.
 928                         Logger::debug('Message is no parent - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 929                         return true;
 930                 }
 931
 932                 $tags = array_column(Tag::getByURIId($item['uri-id'], [Tag::HASHTAG]), 'name');
 933                 if (Relay::isSolicitedPost($tags, $item['body'], $item['author-id'], $item['uri'], Protocol::ACTIVITYPUB)) {
 934                         Logger::debug('Post is accepted because of the relay settings', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 935                         return true;
 936                 } else {
 937                         return false;
 938                 }
 939         }
 940
 941         /**
 942          * Creates an item post
 943          *
 944          * @param array $activity Activity data
 945          * @param array $item     item array
 946          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 947          * @throws \ImagickException
 948          */
 949         public static function postItem(array $activity, array $item)
 950         {
 951                 if (empty($item)) {
 952                         return;
 953                 }
 954
 955                 $stored = false;
 956                 $success = false;
 957                 ksort($activity['receiver']);
 958
 959                 if (!self::isSolicitedMessage($activity, $item)) {
 960                         DBA::delete('item-uri', ['id' => $item['uri-id']]);
 961                         if (!empty($activity['entry-id'])) {
 962                                 Queue::deleteById($activity['entry-id']);
 963                         }
 964                         return;
 965                 }
 966
 967                 foreach ($activity['receiver'] as $receiver) {
 968                         if ($receiver == -1) {
 969                                 continue;
 970                         }
 971
 972                         $item['uid'] = $receiver;
 973
 974                         $type = $activity['reception_type'][$receiver] ?? Receiver::TARGET_UNKNOWN;
 975                         switch($type) {
 976                                 case Receiver::TARGET_TO:
 977                                         $item['post-reason'] = Item::PR_TO;
 978                                         break;
 979                                 case Receiver::TARGET_CC:
 980                                         $item['post-reason'] = Item::PR_CC;
 981                                         break;
 982                                 case Receiver::TARGET_BTO:
 983                                         $item['post-reason'] = Item::PR_BTO;
 984                                         break;
 985                                 case Receiver::TARGET_BCC:
 986                                         $item['post-reason'] = Item::PR_BCC;
 987                                         break;
 988                                 case Receiver::TARGET_FOLLOWER:
 989                                         $item['post-reason'] = Item::PR_FOLLOWER;
 990                                         break;
 991                                 case Receiver::TARGET_ANSWER:
 992                                         $item['post-reason'] = Item::PR_COMMENT;
 993                                         break;
 994                                 case Receiver::TARGET_GLOBAL:
 995                                         $item['post-reason'] = Item::PR_GLOBAL;
 996                                         break;
 997                                 default:
 998                                         $item['post-reason'] = Item::PR_NONE;
 999                         }
1000
1001                         $item['post-reason'] = Item::getPostReason($item);
1002
1003                         if (in_array($item['post-reason'], [Item::PR_GLOBAL, Item::PR_NONE])) {
1004                                 if (!empty($activity['from-relay'])) {
1005                                         $item['post-reason'] = Item::PR_RELAY;
1006                                 } elseif (!empty($activity['thread-completion'])) {
1007                                         $item['post-reason'] = Item::PR_FETCHED;
1008                                 } elseif (!empty($activity['push'])) {
1009                                         $item['post-reason'] = Item::PR_PUSHED;
1010                                 }
1011                         }
1012
1013                         if ($item['isForum'] ?? false) {
1014                                 $item['contact-id'] = Contact::getIdForURL($activity['actor'], $receiver);
1015                         } else {
1016                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver);
1017                         }
1018
1019                         if (($receiver != 0) && empty($item['contact-id'])) {
1020                                 $item['contact-id'] = Contact::getIdForURL($activity['author']);
1021                         }
1022
1023                         if (!empty($activity['directmessage'])) {
1024                                 self::postMail($activity, $item);
1025                                 continue;
1026                         }
1027
1028                         if (($receiver != 0) && ($item['gravity'] == GRAVITY_PARENT) && !in_array($item['post-reason'], [Item::PR_FOLLOWER, Item::PR_TAG, item::PR_TO, Item::PR_CC])) {
1029                                 if (!($item['isForum'] ?? false)) {
1030                                         if ($item['post-reason'] == Item::PR_BCC) {
1031                                                 Logger::info('Top level post via BCC from a non sharer, ignoring', ['uid' => $receiver, 'contact' => $item['contact-id'], 'url' => $item['uri']]);
1032                                                 continue;
1033                                         }
1034
1035                                         if ((DI::pConfig()->get($receiver, 'system', 'accept_only_sharer') != Item::COMPLETION_LIKE)
1036                                                 && in_array($activity['thread-children-type'] ?? '', Receiver::ACTIVITY_TYPES)) {
1037                                                 Logger::info('Top level post from thread completion from a non sharer had been initiated via an activity, ignoring',
1038                                                         ['type' => $activity['thread-children-type'], 'user' => $item['uid'], 'causer' => $item['causer-link'], 'author' => $activity['author'], 'url' => $item['uri']]);
1039                                                 continue;
1040                                         }
1041                                 }
1042
1043                                 $is_forum = false;
1044                                 $user = User::getById($receiver, ['account-type']);
1045                                 if (!empty($user['account-type'])) {
1046                                         $is_forum = ($user['account-type'] == User::ACCOUNT_TYPE_COMMUNITY);
1047                                 }
1048
1049                                 if ((DI::pConfig()->get($receiver, 'system', 'accept_only_sharer') == Item::COMPLETION_NONE)
1050                                         && ((!$is_forum && !($item['isForum'] ?? false) && ($activity['type'] != 'as:Announce'))
1051                                         || !Contact::isSharingByURL($activity['actor'], $receiver))) {
1052                                         Logger::info('Actor is a non sharer, is no forum or it is no announce', ['uid' => $receiver, 'actor' => $activity['actor'], 'url' => $item['uri'], 'type' => $activity['type']]);
1053                                         continue;
1054                                 }
1055
1056                                 Logger::info('Accepting post', ['uid' => $receiver, 'url' => $item['uri']]);
1057                         }
1058
1059                         if (($item['gravity'] != GRAVITY_ACTIVITY) && ($activity['object_type'] == 'as:Event')) {
1060                                 $event_id = self::createEvent($activity, $item);
1061
1062                                 $item = Event::getItemArrayForImportedId($event_id, $item);
1063                         }
1064
1065                         $item_id = Item::insert($item);
1066                         if ($item_id) {
1067                                 Logger::info('Item insertion successful', ['user' => $item['uid'], 'item_id' => $item_id]);
1068                                 $success = true;
1069                         } else {
1070                                 Logger::notice('Item insertion aborted', ['uri' => $item['uri'], 'uid' => $item['uid']]);
1071                                 if (($item['uid'] == 0) && (count($activity['receiver']) > 1)) {
1072                                         Logger::info('Public item was aborted. We skip for all users.', ['uri' => $item['uri']]);
1073                                         break;
1074                                 }
1075                         }
1076
1077                         if ($item['uid'] == 0) {
1078                                 $stored = $item_id;
1079                         }
1080                 }
1081
1082                 Queue::remove($activity);
1083
1084                 if ($success && Queue::hasChildren($item['uri']) && Post::exists(['uri' => $item['uri']])) {
1085                         Queue::processReplyByUri($item['uri']);
1086                 }
1087
1088                 // Store send a follow request for every reshare - but only when the item had been stored
1089                 if ($stored && ($item['private'] != Item::PRIVATE) && ($item['gravity'] == GRAVITY_PARENT) && !empty($item['author-link']) && ($item['author-link'] != $item['owner-link'])) {
1090                         $author = APContact::getByURL($item['owner-link'], false);
1091                         // We send automatic follow requests for reshared messages. (We don't need though for forum posts)
1092                         if ($author['type'] != 'Group') {
1093                                 Logger::info('Send follow request', ['uri' => $item['uri'], 'stored' => $stored, 'to' => $item['author-link']]);
1094                                 ActivityPub\Transmitter::sendFollowObject($item['uri'], $item['author-link']);
1095                         }
1096                 }
1097         }
1098
1099         /**
1100          * Store tags and mentions into the tag table
1101          *
1102          * @param integer $uriid
1103          * @param array $tags
1104          */
1105         private static function storeTags(int $uriid, array $tags = null)
1106         {
1107                 foreach ($tags as $tag) {
1108                         if (empty($tag['name']) || empty($tag['type']) || !in_array($tag['type'], ['Mention', 'Hashtag'])) {
1109                                 continue;
1110                         }
1111
1112                         $hash = substr($tag['name'], 0, 1);
1113
1114                         if ($tag['type'] == 'Mention') {
1115                                 if (in_array($hash, [Tag::TAG_CHARACTER[Tag::MENTION],
1116                                         Tag::TAG_CHARACTER[Tag::EXCLUSIVE_MENTION],
1117                                         Tag::TAG_CHARACTER[Tag::IMPLICIT_MENTION]])) {
1118                                         $tag['name'] = substr($tag['name'], 1);
1119                                 }
1120                                 $type = Tag::IMPLICIT_MENTION;
1121
1122                                 if (!empty($tag['href'])) {
1123                                         $apcontact = APContact::getByURL($tag['href']);
1124                                         if (!empty($apcontact['name']) || !empty($apcontact['nick'])) {
1125                                                 $tag['name'] = $apcontact['name'] ?: $apcontact['nick'];
1126                                         }
1127                                 }
1128                         } elseif ($tag['type'] == 'Hashtag') {
1129                                 if ($hash == Tag::TAG_CHARACTER[Tag::HASHTAG]) {
1130                                         $tag['name'] = substr($tag['name'], 1);
1131                                 }
1132                                 $type = Tag::HASHTAG;
1133                         }
1134
1135                         if (empty($tag['name'])) {
1136                                 continue;
1137                         }
1138
1139                         Tag::store($uriid, $type, $tag['name'], $tag['href']);
1140                 }
1141         }
1142
1143         public static function storeReceivers(int $uriid, array $receivers)
1144         {
1145                 foreach (['as:to' => Tag::TO, 'as:cc' => Tag::CC, 'as:bto' => Tag::BTO, 'as:bcc' => Tag::BCC] as $element => $type) {
1146                         if (!empty($receivers[$element])) {
1147                                 foreach ($receivers[$element] as $receiver) {
1148                                         if ($receiver == ActivityPub::PUBLIC_COLLECTION) {
1149                                                 $name = Receiver::PUBLIC_COLLECTION;
1150                                         } else {
1151                                                 $name = trim(parse_url($receiver, PHP_URL_PATH), '/');
1152                                         }
1153
1154                                         $target = Tag::getTargetType($receiver);
1155                                         Logger::debug('Got target type', ['type' => $target, 'url' => $receiver]);
1156                                         Tag::store($uriid, $type, $name, $receiver, $target);
1157                                 }
1158                         }
1159                 }
1160         }
1161
1162         /**
1163          * Creates an mail post
1164          *
1165          * @param array $activity Activity data
1166          * @param array $item     item array
1167          * @return int|bool New mail table row id or false on error
1168          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1169          */
1170         private static function postMail(array $activity, array $item)
1171         {
1172                 if (($item['gravity'] != GRAVITY_PARENT) && !DBA::exists('mail', ['uri' => $item['thr-parent'], 'uid' => $item['uid']])) {
1173                         Logger::info('Parent not found, mail will be discarded.', ['uid' => $item['uid'], 'uri' => $item['thr-parent']]);
1174                         return false;
1175                 }
1176
1177                 Logger::info('Direct Message', $item);
1178
1179                 $msg = [];
1180                 $msg['uid'] = $item['uid'];
1181
1182                 $msg['contact-id'] = $item['contact-id'];
1183
1184                 $contact = Contact::getById($item['contact-id'], ['name', 'url', 'photo']);
1185                 $msg['from-name'] = $contact['name'];
1186                 $msg['from-url'] = $contact['url'];
1187                 $msg['from-photo'] = $contact['photo'];
1188
1189                 $msg['uri'] = $item['uri'];
1190                 $msg['created'] = $item['created'];
1191
1192                 $parent = DBA::selectFirst('mail', ['parent-uri', 'title'], ['uri' => $item['thr-parent']]);
1193                 if (DBA::isResult($parent)) {
1194                         $msg['parent-uri'] = $parent['parent-uri'];
1195                         $msg['title'] = $parent['title'];
1196                 } else {
1197                         $msg['parent-uri'] = $item['thr-parent'];
1198
1199                         if (!empty($item['title'])) {
1200                                 $msg['title'] = $item['title'];
1201                         } elseif (!empty($item['content-warning'])) {
1202                                 $msg['title'] = $item['content-warning'];
1203                         } else {
1204                                 // Trying to generate a title out of the body
1205                                 $title = $item['body'];
1206
1207                                 while (preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $title, $matches)) {
1208                                         $title = $matches[3];
1209                                 }
1210
1211                                 $title = trim(BBCode::toPlaintext($title));
1212
1213                                 if (strlen($title) > 20) {
1214                                         $title = substr($title, 0, 20) . '...';
1215                                 }
1216
1217                                 $msg['title'] = $title;
1218                         }
1219                 }
1220                 $msg['body'] = $item['body'];
1221
1222                 return Mail::insert($msg);
1223         }
1224
1225         /**
1226          * Fetch featured posts from a contact with the given url
1227          *
1228          * @param string $url
1229          * @return void
1230          */
1231         public static function fetchFeaturedPosts(string $url)
1232         {
1233                 Logger::info('Fetch featured posts', ['contact' => $url]);
1234
1235                 $apcontact = APContact::getByURL($url);
1236                 if (empty($apcontact['featured'])) {
1237                         Logger::info('Contact does not have a featured collection', ['contact' => $url]);
1238                         return;
1239                 }
1240
1241                 $pcid = Contact::getIdForURL($url, 0, false);
1242                 if (empty($pcid)) {
1243                         Logger::info('Contact not found', ['contact' => $url]);
1244                         return;
1245                 }
1246
1247                 $posts = Post\Collection::selectToArrayForContact($pcid, Post\Collection::FEATURED);
1248                 if (!empty($posts)) {
1249                         $old_featured = array_column($posts, 'uri-id');
1250                 } else {
1251                         $old_featured = [];
1252                 }
1253
1254                 $featured = ActivityPub::fetchItems($apcontact['featured']);
1255                 if (empty($featured)) {
1256                         Logger::info('Contact does not have featured posts', ['contact' => $url]);
1257
1258                         foreach ($old_featured as $uri_id) {
1259                                 Post\Collection::remove($uri_id, Post\Collection::FEATURED);
1260                                 Logger::debug('Removed no longer featured post', ['uri-id' => $uri_id, 'contact' => $url]);
1261                         }
1262                         return;
1263                 }
1264
1265                 $new = 0;
1266                 $old = 0;
1267
1268                 foreach ($featured as $post) {
1269                         if (empty($post['id'])) {
1270                                 continue;
1271                         }
1272                         $id = Item::fetchByLink($post['id']);
1273                         if (!empty($id)) {
1274                                 $item = Post::selectFirst(['uri-id', 'featured'], ['id' => $id]);
1275                                 if (!empty($item['uri-id'])) {
1276                                         if (!$item['featured']) {
1277                                                 Post\Collection::add($item['uri-id'], Post\Collection::FEATURED);
1278                                                 Logger::debug('Added featured post', ['uri-id' => $item['uri-id'], 'contact' => $url]);
1279                                                 $new++;
1280                                         } else {
1281                                                 Logger::debug('Post already had been featured', ['uri-id' => $item['uri-id'], 'contact' => $url]);
1282                                                 $old++;
1283                                         }
1284
1285                                         $index = array_search($item['uri-id'], $old_featured);
1286                                         if (!($index === false)) {
1287                                                 unset($old_featured[$index]);
1288                                         }
1289                                 }
1290                         }
1291                 }
1292
1293                 foreach ($old_featured as $uri_id) {
1294                         Post\Collection::remove($uri_id, Post\Collection::FEATURED);
1295                         Logger::debug('Removed no longer featured post', ['uri-id' => $uri_id, 'contact' => $url]);
1296                 }
1297
1298                 Logger::info('Fetched featured posts', ['new' => $new, 'old' => $old, 'contact' => $url]);
1299         }
1300
1301         public static function fetchCachedActivity(string $url, int $uid): array
1302         {
1303                 $cachekey = self::CACHEKEY_FETCH_ACTIVITY . $uid . ':' . $url;
1304                 $object = DI::cache()->get($cachekey);
1305
1306                 if (!is_null($object)) {
1307                         if (!empty($object)) {
1308                                 Logger::debug('Fetch from cache', ['url' => $url, 'uid' => $uid]);
1309                         } else {
1310                                 Logger::debug('Fetch from negative cache', ['url' => $url, 'uid' => $uid]);
1311                         }
1312                         return $object;
1313                 }
1314
1315                 $object = ActivityPub::fetchContent($url, $uid);
1316                 if (empty($object)) {
1317                         Logger::notice('Activity was not fetchable, aborting.', ['url' => $url, 'uid' => $uid]);
1318                         // We perform negative caching.
1319                         DI::cache()->set($cachekey, [], Duration::FIVE_MINUTES);
1320                         return [];
1321                 }
1322
1323                 if (empty($object['id'])) {
1324                         Logger::notice('Activity has got not id, aborting. ', ['url' => $url, 'object' => $object]);
1325                         return [];
1326                 }
1327                 DI::cache()->set($cachekey, $object, Duration::FIVE_MINUTES);
1328
1329                 Logger::debug('Activity was fetched successfully', ['url' => $url, 'uid' => $uid]);
1330
1331                 return $object;
1332         }
1333
1334         /**
1335          * Fetches missing posts
1336          *
1337          * @param string     $url         message URL
1338          * @param array      $child       activity array with the child of this message
1339          * @param string     $relay_actor Relay actor
1340          * @param int        $completion  Completion mode, see Receiver::COMPLETION_*
1341          * @return string fetched message URL
1342          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1343          * @throws \ImagickException
1344          */
1345         public static function fetchMissingActivity(string $url, array $child = [], string $relay_actor = '', int $completion = Receiver::COMPLETION_MANUAL): string
1346         {
1347                 $object = self::fetchCachedActivity($url, 0);
1348                 if (empty($object)) {
1349                         return '';
1350                 }
1351
1352                 $signer = [];
1353
1354                 if (!empty($object['attributedTo'])) {
1355                         $attributed_to = $object['attributedTo'];
1356                         if (is_array($attributed_to)) {
1357                                 $compacted = JsonLD::compact($object);
1358                                 $attributed_to = JsonLD::fetchElement($compacted, 'as:attributedTo', '@id');
1359                         }
1360                         $signer[] = $attributed_to;
1361                 }
1362
1363                 if (!empty($object['actor'])) {
1364                         $object_actor = $object['actor'];
1365                 } elseif (!empty($attributed_to)) {
1366                         $object_actor = $attributed_to;
1367                 } else {
1368                         // Shouldn't happen
1369                         $object_actor = '';
1370                 }
1371
1372                 $signer[] = $object_actor;
1373
1374                 if (!empty($child['author'])) {
1375                         $actor = $child['author'];
1376                         $signer[] = $actor;
1377                 } else {
1378                         $actor = $object_actor;
1379                 }
1380
1381                 if (!empty($object['published'])) {
1382                         $published = $object['published'];
1383                 } elseif (!empty($child['published'])) {
1384                         $published = $child['published'];
1385                 } else {
1386                         $published = DateTimeFormat::utcNow();
1387                 }
1388
1389                 $activity = [];
1390                 $activity['@context'] = $object['@context'] ?? ActivityPub::CONTEXT;
1391                 unset($object['@context']);
1392                 $activity['id'] = $object['id'];
1393                 $activity['to'] = $object['to'] ?? [];
1394                 $activity['cc'] = $object['cc'] ?? [];
1395                 $activity['actor'] = $actor;
1396                 $activity['object'] = $object;
1397                 $activity['published'] = $published;
1398                 $activity['type'] = 'Create';
1399
1400                 $ldactivity = JsonLD::compact($activity);
1401
1402                 $ldactivity['recursion-depth'] = !empty($child['recursion-depth']) ? $child['recursion-depth'] + 1 : 0;
1403
1404                 if (!empty($relay_actor)) {
1405                         $ldactivity['thread-completion'] = $ldactivity['from-relay'] = Contact::getIdForURL($relay_actor);
1406                         $ldactivity['completion-mode']   = Receiver::COMPLETION_RELAY;
1407                 } elseif (!empty($child['thread-completion'])) {
1408                         $ldactivity['thread-completion'] = $child['thread-completion'];
1409                         $ldactivity['completion-mode']   = $child['completion-mode'] ?? Receiver::COMPLETION_NONE;
1410                 } else {
1411                         $ldactivity['thread-completion'] = Contact::getIdForURL($actor);
1412                         $ldactivity['completion-mode']   = $completion;
1413                 }
1414
1415                 if (!empty($child['thread-children-type'])) {
1416                         $ldactivity['thread-children-type'] = $child['thread-children-type'];
1417                 } elseif (!empty($child['type'])) {
1418                         $ldactivity['thread-children-type'] = $child['type'];
1419                 } else {
1420                         $ldactivity['thread-children-type'] = 'as:Create';
1421                 }
1422
1423                 if (!empty($relay_actor) && !self::acceptIncomingMessage($ldactivity, $object['id'])) {
1424                         return '';
1425                 }
1426
1427                 if (($completion == Receiver::COMPLETION_RELAY) && Queue::exists($url, 'as:Create')) {
1428                         Logger::notice('Activity has already been queued.', ['url' => $url, 'object' => $activity['id']]);
1429                 } elseif (ActivityPub\Receiver::processActivity($ldactivity, json_encode($activity), 0, true, false, $signer, '', $completion)) {
1430                         Logger::notice('Activity had been fetched and processed.', ['url' => $url, 'entry' => $child['entry-id'] ?? 0, 'completion' => $completion, 'object' => $activity['id']]);
1431                 } else {
1432                         Logger::notice('Activity had been fetched and will be processed later.', ['url' => $url, 'entry' => $child['entry-id'] ?? 0, 'completion' => $completion, 'object' => $activity['id']]);
1433                 }
1434
1435                 return $activity['id'];
1436         }
1437
1438         /**
1439          * Test if incoming relay messages should be accepted
1440          *
1441          * @param array $activity activity array
1442          * @param string $id      object ID
1443          * @return boolean true if message is accepted
1444          */
1445         private static function acceptIncomingMessage(array $activity, string $id): bool
1446         {
1447                 if (empty($activity['as:object'])) {
1448                         Logger::info('No object field in activity - accepted', ['id' => $id]);
1449                         return true;
1450                 }
1451
1452                 $replyto = JsonLD::fetchElement($activity['as:object'], 'as:inReplyTo', '@id');
1453                 $uriid = ItemURI::getIdByURI($replyto ?? '');
1454                 if (Post::exists(['uri-id' => $uriid])) {
1455                         Logger::info('Post is a reply to an existing post - accepted', ['id' => $id, 'uri-id' => $uriid, 'replyto' => $replyto]);
1456                         return true;
1457                 }
1458
1459                 $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
1460                 $authorid = Contact::getIdForURL($attributed_to);
1461
1462                 $body = HTML::toBBCode(JsonLD::fetchElement($activity['as:object'], 'as:content', '@value') ?? '');
1463
1464                 $messageTags = [];
1465                 $tags = Receiver::processTags(JsonLD::fetchElementArray($activity['as:object'], 'as:tag') ?? []);
1466                 if (!empty($tags)) {
1467                         foreach ($tags as $tag) {
1468                                 if ($tag['type'] != 'Hashtag') {
1469                                         continue;
1470                                 }
1471                                 $messageTags[] = ltrim(mb_strtolower($tag['name']), '#');
1472                         }
1473                 }
1474
1475                 return Relay::isSolicitedPost($messageTags, $body, $authorid, $id, Protocol::ACTIVITYPUB);
1476         }
1477
1478         /**
1479          * perform a "follow" request
1480          *
1481          * @param array $activity
1482          * @return void
1483          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1484          * @throws \ImagickException
1485          */
1486         public static function followUser(array $activity)
1487         {
1488                 $uid = User::getIdForURL($activity['object_id']);
1489                 if (empty($uid)) {
1490                         Queue::remove($activity);
1491                         return;
1492                 }
1493
1494                 $owner = User::getOwnerDataById($uid);
1495                 if (empty($owner)) {
1496                         return;
1497                 }
1498
1499                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1500                 if (!empty($cid)) {
1501                         self::switchContact($cid);
1502                         Contact::update(['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
1503                 }
1504
1505                 $item = [
1506                         'author-id' => Contact::getIdForURL($activity['actor']),
1507                         'author-link' => $activity['actor'],
1508                 ];
1509
1510                 // Ensure that the contact has got the right network type
1511                 self::switchContact($item['author-id']);
1512
1513                 $result = Contact::addRelationship($owner, [], $item, false, $activity['content'] ?? '');
1514                 if ($result === true) {
1515                         ActivityPub\Transmitter::sendContactAccept($item['author-link'], $activity['id'], $owner['uid']);
1516                 }
1517
1518                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1519                 if (empty($cid)) {
1520                         return;
1521                 }
1522
1523                 if ($result && DI::config()->get('system', 'transmit_pending_events') && ($owner['contact-type'] == Contact::TYPE_COMMUNITY)) {
1524                         self::transmitPendingEvents($cid, $owner['uid']);
1525                 }
1526
1527                 if (empty($contact)) {
1528                         Contact::update(['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
1529                 }
1530                 Logger::notice('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
1531                 Queue::remove($activity);
1532         }
1533
1534         /**
1535          * Transmit pending events to the new follower
1536          *
1537          * @param integer $cid Contact id
1538          * @param integer $uid User id
1539          * @return void
1540          */
1541         private static function transmitPendingEvents(int $cid, int $uid)
1542         {
1543                 $account = DBA::selectFirst('account-user-view', ['ap-inbox', 'ap-sharedinbox'], ['id' => $cid]);
1544                 $inbox = $account['ap-sharedinbox'] ?: $account['ap-inbox'];
1545
1546                 $events = DBA::select('event', ['id'], ["`uid` = ? AND `start` > ? AND `type` != ?", $uid, DateTimeFormat::utcNow(), 'birthday']);
1547                 while ($event = DBA::fetch($events)) {
1548                         $post = Post::selectFirst(['id', 'uri-id', 'created'], ['event-id' => $event['id']]);
1549                         if (empty($post)) {
1550                                 continue;
1551                         }
1552                         if (DI::config()->get('system', 'bulk_delivery')) {
1553                                 Post\Delivery::add($post['uri-id'], $uid, $inbox, $post['created'], Delivery::POST, [$cid]);
1554                                 Worker::add(PRIORITY_HIGH, 'APDelivery', '', 0, $inbox, 0);
1555                         } else {
1556                                 Worker::add(PRIORITY_HIGH, 'APDelivery', Delivery::POST, $post['id'], $inbox, $uid, [$cid], $post['uri-id']);
1557                         }
1558                 }
1559         }
1560
1561         /**
1562          * Update the given profile
1563          *
1564          * @param array $activity
1565          * @throws \Exception
1566          */
1567         public static function updatePerson(array $activity)
1568         {
1569                 if (empty($activity['object_id'])) {
1570                         return;
1571                 }
1572
1573                 Logger::info('Updating profile', ['object' => $activity['object_id']]);
1574                 Contact::updateFromProbeByURL($activity['object_id']);
1575                 Queue::remove($activity);
1576         }
1577
1578         /**
1579          * Delete the given profile
1580          *
1581          * @param array $activity
1582          * @return void
1583          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1584          */
1585         public static function deletePerson(array $activity)
1586         {
1587                 if (empty($activity['object_id']) || empty($activity['actor'])) {
1588                         Logger::info('Empty object id or actor.');
1589                         return;
1590                 }
1591
1592                 if ($activity['object_id'] != $activity['actor']) {
1593                         Logger::info('Object id does not match actor.');
1594                         return;
1595                 }
1596
1597                 $contacts = DBA::select('contact', ['id'], ['nurl' => Strings::normaliseLink($activity['object_id'])]);
1598                 while ($contact = DBA::fetch($contacts)) {
1599                         Contact::remove($contact['id']);
1600                 }
1601                 DBA::close($contacts);
1602
1603                 Logger::info('Deleted contact', ['object' => $activity['object_id']]);
1604                 Queue::remove($activity);
1605         }
1606
1607         /**
1608          * Blocks the user by the contact
1609          *
1610          * @param array $activity
1611          * @return void
1612          * @throws \Exception
1613          */
1614         public static function blockAccount(array $activity)
1615         {
1616                 $cid = Contact::getIdForURL($activity['actor']);
1617                 if (empty($cid)) {
1618                         return;
1619                 }
1620
1621                 $uid = User::getIdForURL($activity['object_id']);
1622                 if (empty($uid)) {
1623                         return;
1624                 }
1625
1626                 Contact\User::setIsBlocked($cid, $uid, true);
1627
1628                 Logger::info('Contact blocked user', ['contact' => $cid, 'user' => $uid]);
1629                 Queue::remove($activity);
1630         }
1631
1632         /**
1633          * Unblocks the user by the contact
1634          *
1635          * @param array $activity
1636          * @return void
1637          * @throws \Exception
1638          */
1639         public static function unblockAccount(array $activity)
1640         {
1641                 $cid = Contact::getIdForURL($activity['actor']);
1642                 if (empty($cid)) {
1643                         return;
1644                 }
1645
1646                 $uid = User::getIdForURL($activity['object_object']);
1647                 if (empty($uid)) {
1648                         return;
1649                 }
1650
1651                 Contact\User::setIsBlocked($cid, $uid, false);
1652
1653                 Logger::info('Contact unblocked user', ['contact' => $cid, 'user' => $uid]);
1654                 Queue::remove($activity);
1655         }
1656
1657         /**
1658          * Accept a follow request
1659          *
1660          * @param array $activity
1661          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1662          * @throws \ImagickException
1663          */
1664         public static function acceptFollowUser(array $activity)
1665         {
1666                 $uid = User::getIdForURL($activity['object_actor']);
1667                 if (empty($uid)) {
1668                         return;
1669                 }
1670
1671                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1672                 if (empty($cid)) {
1673                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1674                         return;
1675                 }
1676
1677                 self::switchContact($cid);
1678
1679                 $fields = ['pending' => false];
1680
1681                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
1682                 if ($contact['rel'] == Contact::FOLLOWER) {
1683                         $fields['rel'] = Contact::FRIEND;
1684                 }
1685
1686                 $condition = ['id' => $cid];
1687                 Contact::update($fields, $condition);
1688                 Logger::info('Accept contact request', ['contact' => $cid, 'user' => $uid]);
1689                 Queue::remove($activity);
1690         }
1691
1692         /**
1693          * Reject a follow request
1694          *
1695          * @param array $activity
1696          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1697          * @throws \ImagickException
1698          */
1699         public static function rejectFollowUser(array $activity)
1700         {
1701                 $uid = User::getIdForURL($activity['object_actor']);
1702                 if (empty($uid)) {
1703                         return;
1704                 }
1705
1706                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1707                 if (empty($cid)) {
1708                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1709                         return;
1710                 }
1711
1712                 self::switchContact($cid);
1713
1714                 $contact = Contact::getById($cid, ['rel']);
1715                 if ($contact['rel'] == Contact::SHARING) {
1716                         Contact::remove($cid);
1717                         Logger::info('Rejected contact request - contact removed', ['contact' => $cid, 'user' => $uid]);
1718                 } elseif ($contact['rel'] == Contact::FRIEND) {
1719                         Contact::update(['rel' => Contact::FOLLOWER], ['id' => $cid]);
1720                 } else {
1721                         Logger::info('Rejected contact request', ['contact' => $cid, 'user' => $uid]);
1722                 }
1723                 Queue::remove($activity);
1724         }
1725
1726         /**
1727          * Undo activity like "like" or "dislike"
1728          *
1729          * @param array $activity
1730          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1731          * @throws \ImagickException
1732          */
1733         public static function undoActivity(array $activity)
1734         {
1735                 if (empty($activity['object_id'])) {
1736                         return;
1737                 }
1738
1739                 if (empty($activity['object_actor'])) {
1740                         return;
1741                 }
1742
1743                 $author_id = Contact::getIdForURL($activity['object_actor']);
1744                 if (empty($author_id)) {
1745                         return;
1746                 }
1747
1748                 Item::markForDeletion(['uri' => $activity['object_id'], 'author-id' => $author_id, 'gravity' => GRAVITY_ACTIVITY]);
1749                 Queue::remove($activity);
1750         }
1751
1752         /**
1753          * Activity to remove a follower
1754          *
1755          * @param array $activity
1756          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1757          * @throws \ImagickException
1758          */
1759         public static function undoFollowUser(array $activity)
1760         {
1761                 $uid = User::getIdForURL($activity['object_object']);
1762                 if (empty($uid)) {
1763                         return;
1764                 }
1765
1766                 $owner = User::getOwnerDataById($uid);
1767                 if (empty($owner)) {
1768                         return;
1769                 }
1770
1771                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1772                 if (empty($cid)) {
1773                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1774                         return;
1775                 }
1776
1777                 self::switchContact($cid);
1778
1779                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1780                 if (!DBA::isResult($contact)) {
1781                         return;
1782                 }
1783
1784                 Contact::removeFollower($contact);
1785                 Logger::info('Undo following request', ['contact' => $cid, 'user' => $uid]);
1786                 Queue::remove($activity);
1787         }
1788
1789         /**
1790          * Switches a contact to AP if needed
1791          *
1792          * @param integer $cid Contact ID
1793          * @return void
1794          * @throws \Exception
1795          */
1796         private static function switchContact(int $cid)
1797         {
1798                 $contact = DBA::selectFirst('contact', ['network', 'url'], ['id' => $cid]);
1799                 if (!DBA::isResult($contact) || in_array($contact['network'], [Protocol::ACTIVITYPUB, Protocol::DFRN]) || Contact::isLocal($contact['url'])) {
1800                         return;
1801                 }
1802
1803                 Logger::info('Change existing contact', ['cid' => $cid, 'previous' => $contact['network']]);
1804                 Contact::updateFromProbe($cid);
1805         }
1806
1807         /**
1808          * Collects implicit mentions like:
1809          * - the author of the parent item
1810          * - all the mentioned conversants in the parent item
1811          *
1812          * @param array $parent Item array with at least ['id', 'author-link', 'alias']
1813          * @return array
1814          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1815          */
1816         private static function getImplicitMentionList(array $parent): array
1817         {
1818                 $parent_terms = Tag::getByURIId($parent['uri-id'], [Tag::MENTION, Tag::IMPLICIT_MENTION, Tag::EXCLUSIVE_MENTION]);
1819
1820                 $parent_author = Contact::getByURL($parent['author-link'], false, ['url', 'nurl', 'alias']);
1821
1822                 $implicit_mentions = [];
1823                 if (empty($parent_author['url'])) {
1824                         Logger::notice('Author public contact unknown.', ['author-link' => $parent['author-link'], 'parent-id' => $parent['id']]);
1825                 } else {
1826                         $implicit_mentions[] = $parent_author['url'];
1827                         $implicit_mentions[] = $parent_author['nurl'];
1828                         $implicit_mentions[] = $parent_author['alias'];
1829                 }
1830
1831                 if (!empty($parent['alias'])) {
1832                         $implicit_mentions[] = $parent['alias'];
1833                 }
1834
1835                 foreach ($parent_terms as $term) {
1836                         $contact = Contact::getByURL($term['url'], false, ['url', 'nurl', 'alias']);
1837                         if (!empty($contact['url'])) {
1838                                 $implicit_mentions[] = $contact['url'];
1839                                 $implicit_mentions[] = $contact['nurl'];
1840                                 $implicit_mentions[] = $contact['alias'];
1841                         }
1842                 }
1843
1844                 return $implicit_mentions;
1845         }
1846
1847         /**
1848          * Strips from the body prepended implicit mentions
1849          *
1850          * @param string $body
1851          * @param array $parent
1852          * @return string
1853          */
1854         private static function removeImplicitMentionsFromBody(string $body, array $parent): string
1855         {
1856                 if (DI::config()->get('system', 'disable_implicit_mentions')) {
1857                         return $body;
1858                 }
1859
1860                 $potential_mentions = self::getImplicitMentionList($parent);
1861
1862                 $kept_mentions = [];
1863
1864                 // Extract one prepended mention at a time from the body
1865                 while(preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $body, $matches)) {
1866                         if (!in_array($matches[2], $potential_mentions)) {
1867                                 $kept_mentions[] = $matches[1];
1868                         }
1869
1870                         $body = $matches[3];
1871                 }
1872
1873                 // Re-appending the kept mentions to the body after extraction
1874                 $kept_mentions[] = $body;
1875
1876                 return implode('', $kept_mentions);
1877         }
1878
1879         /**
1880          * Adds links to string mentions
1881          *
1882          * @param string $body
1883          * @param array  $tags
1884          * @return string
1885          */
1886         protected static function addMentionLinks(string $body, array $tags): string
1887         {
1888                 // This prevents links to be added again to Pleroma-style mention links
1889                 $body = self::normalizeMentionLinks($body);
1890
1891                 $body = BBCode::performWithEscapedTags($body, ['url'], function ($body) use ($tags) {
1892                         foreach ($tags as $tag) {
1893                                 if (empty($tag['name']) || empty($tag['type']) || empty($tag['href']) || !in_array($tag['type'], ['Mention', 'Hashtag'])) {
1894                                         continue;
1895                                 }
1896
1897                                 $hash = substr($tag['name'], 0, 1);
1898                                 $name = substr($tag['name'], 1);
1899                                 if (!in_array($hash, Tag::TAG_CHARACTER)) {
1900                                         $hash = '';
1901                                         $name = $tag['name'];
1902                                 }
1903
1904                                 $body = str_replace($tag['name'], $hash . '[url=' . $tag['href'] . ']' . $name . '[/url]', $body);
1905                         }
1906
1907                         return $body;
1908                 });
1909
1910                 return $body;
1911         }
1912 }