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('fetched-activity', ["`received` < ?", DateTimeFormat::utc('now - 5 minutes')]);
  73                 DBA::insert('fetched-activity', ['object-id' => $id, 'received' => DateTimeFormat::utcNow()]);
  74         }
  75
  76         /**
  77          * Checks if the given object id has just been fetched
  78          *
  79          * @param string $id
  80          *
  81          * @return boolean
  82          */
  83         private static function isFetched(string $id): bool
  84         {
  85                 return DBA::exists('fetched-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::notice('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                 $item = [];
 307                 $item['verb'] = Activity::POST;
 308                 $item['thr-parent'] = $activity['reply-to-id'];
 309
 310                 if ($activity['reply-to-id'] == $activity['id']) {
 311                         $item['gravity'] = GRAVITY_PARENT;
 312                         $item['object-type'] = Activity\ObjectType::NOTE;
 313                 } else {
 314                         $item['gravity'] = GRAVITY_COMMENT;
 315                         $item['object-type'] = Activity\ObjectType::COMMENT;
 316                 }
 317
 318                 if (!empty($activity['conversation'])) {
 319                         $item['conversation'] = $activity['conversation'];
 320                 } elseif (!empty($activity['context'])) {
 321                         $item['conversation'] = $activity['context'];
 322                 }
 323
 324                 if (!empty($item['conversation'])) {
 325                         $conversation = Post::selectFirstThread(['uri'], ['conversation' => $item['conversation']]);
 326                         if (!empty($conversation)) {
 327                                 Logger::debug('Got conversation', ['conversation' => $item['conversation'], 'parent' => $conversation]);
 328                                 $item['parent-uri'] = $conversation['uri'];
 329                                 $item['parent-uri-id'] = ItemURI::getIdByURI($item['parent-uri']);
 330                         }
 331                 } else {
 332                         $conversation = [];
 333                 }
 334
 335                 Logger::debug('Create Item', ['id' => $activity['id'], 'conversation' => $item['conversation'] ?? '']);
 336                 if (empty($activity['author']) && empty($activity['actor'])) {
 337                         Logger::notice('Missing author and actor. We quit here.', ['activity' => $activity]);
 338                         Queue::remove($activity);
 339                         return [];
 340                 }
 341
 342                 if (!in_array(0, $activity['receiver']) || !DI::config()->get('system', 'fetch_parents')) {
 343                         $fetch_parents = false;
 344                 }
 345
 346                 if ($fetch_parents && empty($activity['directmessage']) && ($activity['id'] != $activity['reply-to-id']) && !Post::exists(['uri' => $activity['reply-to-id']])) {
 347                         $result = self::fetchParent($activity, !empty($conversation));
 348                         if (!empty($result)) {
 349                                 if (($item['thr-parent'] != $result) && Post::exists(['uri' => $result])) {
 350                                         $item['thr-parent'] = $result;
 351                                 }
 352                         } elseif (empty($conversation)) {
 353                                 return [];
 354                         }
 355                 }
 356
 357                 $item['diaspora_signed_text'] = $activity['diaspora:comment'] ?? '';
 358
 359                 if (empty($conversation) && empty($activity['directmessage']) && ($item['gravity'] != GRAVITY_PARENT) && !Post::exists(['uri' => $item['thr-parent']])) {
 360                         Logger::notice('Parent not found, message will be discarded.', ['thr-parent' => $item['thr-parent']]);
 361                         if (!$fetch_parents) {
 362                                 Queue::remove($activity);
 363                         }
 364                         return [];
 365                 }
 366
 367                 $item['network'] = Protocol::ACTIVITYPUB;
 368                 $item['author-link'] = $activity['author'];
 369                 $item['author-id'] = Contact::getIdForURL($activity['author']);
 370                 $item['owner-link'] = $activity['actor'];
 371                 $item['owner-id'] = Contact::getIdForURL($activity['actor']);
 372
 373                 if (in_array(0, $activity['receiver']) && !empty($activity['unlisted'])) {
 374                         $item['private'] = Item::UNLISTED;
 375                 } elseif (in_array(0, $activity['receiver'])) {
 376                         $item['private'] = Item::PUBLIC;
 377                 } else {
 378                         $item['private'] = Item::PRIVATE;
 379                 }
 380
 381                 if (!empty($activity['raw'])) {
 382                         $item['source'] = $activity['raw'];
 383                 }
 384
 385                 $item['protocol'] = Conversation::PARCEL_ACTIVITYPUB;
 386
 387                 if (isset($activity['push'])) {
 388                         $item['direction'] = $activity['push'] ? Conversation::PUSH : Conversation::PULL;
 389                 }
 390
 391                 if (!empty($activity['from-relay'])) {
 392                         $item['direction'] = Conversation::RELAY;
 393                 }
 394
 395                 if ($activity['object_type'] == 'as:Article') {
 396                         $item['post-type'] = Item::PT_ARTICLE;
 397                 } elseif ($activity['object_type'] == 'as:Audio') {
 398                         $item['post-type'] = Item::PT_AUDIO;
 399                 } elseif ($activity['object_type'] == 'as:Document') {
 400                         $item['post-type'] = Item::PT_DOCUMENT;
 401                 } elseif ($activity['object_type'] == 'as:Event') {
 402                         $item['post-type'] = Item::PT_EVENT;
 403                 } elseif ($activity['object_type'] == 'as:Image') {
 404                         $item['post-type'] = Item::PT_IMAGE;
 405                 } elseif ($activity['object_type'] == 'as:Page') {
 406                         $item['post-type'] = Item::PT_PAGE;
 407                 } elseif ($activity['object_type'] == 'as:Question') {
 408                         $item['post-type'] = Item::PT_POLL;
 409                 } elseif ($activity['object_type'] == 'as:Video') {
 410                         $item['post-type'] = Item::PT_VIDEO;
 411                 } else {
 412                         $item['post-type'] = Item::PT_NOTE;
 413                 }
 414
 415                 $item['isForum'] = false;
 416
 417                 if (!empty($activity['thread-completion'])) {
 418                         if ($activity['thread-completion'] != $item['owner-id']) {
 419                                 $actor = Contact::getById($activity['thread-completion'], ['url']);
 420                                 $item['causer-link'] = $actor['url'];
 421                                 $item['causer-id'] = $activity['thread-completion'];
 422                                 Logger::info('Use inherited actor as causer.', ['id' => $item['owner-id'], 'activity' => $activity['thread-completion'], 'owner' => $item['owner-link'], 'actor' => $actor['url']]);
 423                         } else {
 424                                 // Store the original actor in the "causer" fields to enable the check for ignored or blocked contacts
 425                                 $item['causer-link'] = $item['owner-link'];
 426                                 $item['causer-id']   = $item['owner-id'];
 427                                 Logger::info('Use actor as causer.', ['id' => $item['owner-id'], 'actor' => $item['owner-link']]);
 428                         }
 429
 430                         $item['owner-link'] = $item['author-link'];
 431                         $item['owner-id'] = $item['author-id'];
 432                 } else {
 433                         $actor = APContact::getByURL($item['owner-link'], false);
 434                         $item['isForum'] = ($actor['type'] == 'Group');
 435                 }
 436
 437                 $item['uri'] = $activity['id'];
 438
 439                 if (empty($activity['published']) || empty($activity['updated'])) {
 440                         DI::logger()->notice('published or updated keys are empty for activity', ['activity' => $activity, 'callstack' => System::callstack(10)]);
 441                 }
 442
 443                 $item['created'] = DateTimeFormat::utc($activity['published'] ?? 'now');
 444                 $item['edited'] = DateTimeFormat::utc($activity['updated'] ?? 'now');
 445                 $guid = $activity['sc:identifier'] ?: self::getGUIDByURL($item['uri']);
 446                 $item['guid'] = $activity['diaspora:guid'] ?: $guid;
 447
 448                 $item['uri-id'] = ItemURI::insert(['uri' => $item['uri'], 'guid' => $item['guid']]);
 449                 if (empty($item['uri-id'])) {
 450                         Logger::warning('Unable to get a uri-id for an item uri', ['uri' => $item['uri'], 'guid' => $item['guid']]);
 451                         return [];
 452                 }
 453
 454                 $item['thr-parent-id'] = ItemURI::getIdByURI($item['thr-parent']);
 455
 456                 $item = self::processContent($activity, $item);
 457                 if (empty($item)) {
 458                         Logger::info('Message was not processed');
 459                         Queue::remove($activity);
 460                         return [];
 461                 }
 462
 463                 $item['plink'] = $activity['alternate-url'] ?? $item['uri'];
 464
 465                 self::storeAttachments($activity, $item);
 466                 self::storeQuestion($activity, $item);
 467
 468                 // We received the post via AP, so we set the protocol of the server to AP
 469                 $contact = Contact::getById($item['author-id'], ['gsid']);
 470                 if (!empty($contact['gsid'])) {
 471                         GServer::setProtocol($contact['gsid'], Post\DeliveryData::ACTIVITYPUB);
 472                 }
 473
 474                 if ($item['author-id'] != $item['owner-id']) {
 475                         $contact = Contact::getById($item['owner-id'], ['gsid']);
 476                         if (!empty($contact['gsid'])) {
 477                                 GServer::setProtocol($contact['gsid'], Post\DeliveryData::ACTIVITYPUB);
 478                         }
 479                 }
 480
 481                 return $item;
 482         }
 483
 484         /**
 485          * Fetch and process parent posts for the given activity
 486          *
 487          * @param array $activity
 488          * @param bool  $in_background
 489          *
 490          * @return string
 491          */
 492         private static function fetchParent(array $activity, bool $in_background = false): string
 493         {
 494                 if (self::isFetched($activity['reply-to-id'])) {
 495                         Logger::info('Id is already fetched', ['id' => $activity['reply-to-id']]);
 496                         return '';
 497                 }
 498
 499                 self::addActivityId($activity['reply-to-id']);
 500
 501                 if (!DI::config()->get('system', 'fetch_by_worker')) {
 502                         $in_background = false;
 503                 }
 504
 505                 $recursion_depth = $activity['recursion-depth'] ?? 0;
 506
 507                 if (!$in_background && ($recursion_depth < DI::config()->get('system', 'max_recursion_depth'))) {
 508                         Logger::notice('Parent not found. Try to refetch it.', ['parent' => $activity['reply-to-id'], 'recursion-depth' => $recursion_depth]);
 509                         $result = self::fetchMissingActivity($activity['reply-to-id'], $activity, '', Receiver::COMPLETION_AUTO);
 510                         if (empty($result) && self::isActivityGone($activity['reply-to-id'])) {
 511                                 Logger::notice('The activity is gone, the queue entry will be deleted', ['parent' => $activity['reply-to-id']]);
 512                                 if (!empty($activity['entry-id'])) {
 513                                         Queue::deleteById($activity['entry-id']);
 514                                 }
 515                                 return '';
 516                         } elseif (!empty($result)) {
 517                                 $exists = Post::exists(['uri' => [$result, $activity['reply-to-id']]]);
 518                                 if ($exists) {
 519                                         Logger::notice('The activity has been fetched and created.', ['parent' => $result]);
 520                                         return $result;
 521                                 } elseif (DI::config()->get('system', 'fetch_by_worker') || DI::config()->get('system', 'decoupled_receiver')) {
 522                                         Logger::notice('The activity has been fetched and will hopefully be created later.', ['parent' => $result]);
 523                                 } else {
 524                                         Logger::notice('The activity exists but has not been created, the queue entry will be deleted.', ['parent' => $result]);
 525                                         if (!empty($activity['entry-id'])) {
 526                                                 Queue::deleteById($activity['entry-id']);
 527                                         }
 528                                 }
 529                                 return '';
 530                         }
 531                         if (empty($result) && !DI::config()->get('system', 'fetch_by_worker')) {
 532                                 return '';
 533                         }
 534                 } elseif (self::isActivityGone($activity['reply-to-id'])) {
 535                         Logger::notice('The activity is gone. We will not spawn a worker. The queue entry will be deleted', ['parent' => $activity['reply-to-id']]);
 536                         if ($in_background) {
 537                                 // fetching in background is done for all activities where we have got the conversation
 538                                 // There we only delete the single activity and not the whole thread since we can store the
 539                                 // other posts in the thread even with missing posts.
 540                                 Queue::remove($activity);
 541                         } elseif (!empty($activity['entry-id'])) {
 542                                 Queue::deleteById($activity['entry-id']);
 543                         }
 544                         return '';
 545                 } elseif ($in_background) {
 546                         Logger::notice('Fetching is done in the background.', ['parent' => $activity['reply-to-id']]);
 547                 } else {
 548                         Logger::notice('Recursion level is too high.', ['parent' => $activity['reply-to-id'], 'recursion-depth' => $recursion_depth]);
 549                 }
 550
 551                 if (!Fetch::hasWorker($activity['reply-to-id'])) {
 552                         Logger::notice('Fetching is done by worker.', ['parent' => $activity['reply-to-id'], 'recursion-depth' => $recursion_depth]);
 553                         Fetch::add($activity['reply-to-id']);
 554                         $activity['recursion-depth'] = 0;
 555                         $wid = Worker::add(PRIORITY_HIGH, 'FetchMissingActivity', $activity['reply-to-id'], $activity, '', Receiver::COMPLETION_AUTO);
 556                         Fetch::setWorkerId($activity['reply-to-id'], $wid);
 557                 } else {
 558                         Logger::debug('Activity will already be fetched via a worker.', ['url' => $activity['reply-to-id']]);
 559                 }
 560
 561                 return '';
 562         }
 563
 564         /**
 565          * Check if a given activity is no longer available
 566          *
 567          * @param string $url
 568          *
 569          * @return boolean
 570          */
 571         public static function isActivityGone(string $url): bool
 572         {
 573                 $curlResult = HTTPSignature::fetchRaw($url, 0);
 574
 575                 if (Network::isUrlBlocked($url)) {
 576                         return true;
 577                 }
 578
 579                 // @todo To ensure that the remote system is working correctly, we can check if the "Content-Type" contains JSON
 580                 if (in_array($curlResult->getReturnCode(), [401, 404])) {
 581                         return true;
 582                 }
 583
 584                 if ($curlResult->isSuccess()) {
 585                         $object = json_decode($curlResult->getBody(), true);
 586                         if (!empty($object)) {
 587                                 $activity = JsonLD::compact($object);
 588                                 if (JsonLD::fetchElement($activity, '@type') == 'as:Tombstone') {
 589                                         return true;
 590                                 }
 591                         }
 592                 } elseif ($curlResult->getReturnCode() == 0) {
 593                         $host = parse_url($url, PHP_URL_HOST);
 594                         if (!(filter_var($host, FILTER_VALIDATE_IP) || @dns_get_record($host . '.', DNS_A + DNS_AAAA))) {
 595                                 return true;
 596                         }
 597                 }
 598
 599                 return false;
 600         }
 601         /**
 602          * Delete items
 603          *
 604          * @param array $activity
 605          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 606          * @throws \ImagickException
 607          */
 608         public static function deleteItem(array $activity)
 609         {
 610                 $owner = Contact::getIdForURL($activity['actor']);
 611
 612                 Logger::info('Deleting item', ['object' => $activity['object_id'], 'owner'  => $owner]);
 613                 Item::markForDeletion(['uri' => $activity['object_id'], 'owner-id' => $owner]);
 614                 Queue::remove($activity);
 615         }
 616
 617         /**
 618          * Prepare the item array for an activity
 619          *
 620          * @param array $activity Activity array
 621          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 622          * @throws \ImagickException
 623          */
 624         public static function addTag(array $activity)
 625         {
 626                 if (empty($activity['object_content']) || empty($activity['object_id'])) {
 627                         return;
 628                 }
 629
 630                 foreach ($activity['receiver'] as $receiver) {
 631                         $item = Post::selectFirst(['id', 'uri-id', 'origin', 'author-link'], ['uri' => $activity['target_id'], 'uid' => $receiver]);
 632                         if (!DBA::isResult($item)) {
 633                                 // We don't fetch missing content for this purpose
 634                                 continue;
 635                         }
 636
 637                         if (($item['author-link'] != $activity['actor']) && !$item['origin']) {
 638                                 Logger::info('Not origin, not from the author, skipping update', ['id' => $item['id'], 'author' => $item['author-link'], 'actor' => $activity['actor']]);
 639                                 continue;
 640                         }
 641
 642                         Tag::store($item['uri-id'], Tag::HASHTAG, $activity['object_content'], $activity['object_id']);
 643                         Logger::info('Tagged item', ['id' => $item['id'], 'tag' => $activity['object_content'], 'uri' => $activity['target_id'], 'actor' => $activity['actor']]);
 644                 }
 645         }
 646
 647         /**
 648          * Prepare the item array for an activity
 649          *
 650          * @param array      $activity   Activity array
 651          * @param string     $verb       Activity verb
 652          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 653          * @throws \ImagickException
 654          */
 655         public static function createActivity(array $activity, string $verb)
 656         {
 657                 $activity['reply-to-id'] = $activity['object_id'];
 658                 $item = self::createItem($activity, false);
 659                 if (empty($item)) {
 660                         Logger::debug('Activity was not prepared', ['id' => $activity['object_id']]);
 661                         return;
 662                 }
 663
 664                 $item['verb'] = $verb;
 665                 $item['thr-parent'] = $activity['object_id'];
 666                 $item['gravity'] = GRAVITY_ACTIVITY;
 667                 unset($item['post-type']);
 668                 $item['object-type'] = Activity\ObjectType::NOTE;
 669
 670                 if (!empty($activity['content'])) {
 671                         $item['body'] = HTML::toBBCode($activity['content']);
 672                 }
 673
 674                 $item['diaspora_signed_text'] = $activity['diaspora:like'] ?? '';
 675
 676                 self::postItem($activity, $item);
 677         }
 678
 679         /**
 680          * Fetch the Uri-Id of a post for the "featured" collection
 681          *
 682          * @param array $activity
 683          * @return null|array
 684          */
 685         private static function getUriIdForFeaturedCollection(array $activity)
 686         {
 687                 $actor = APContact::getByURL($activity['actor']);
 688                 if (empty($actor)) {
 689                         return null;
 690                 }
 691
 692                 // Refetch the account when the "featured" collection is missing.
 693                 // This can be removed in a future version (end of 2022 should be good).
 694                 if (empty($actor['featured'])) {
 695                         $actor = APContact::getByURL($activity['actor'], true);
 696                         if (empty($actor)) {
 697                                 return null;
 698                         }
 699                 }
 700
 701                 $parent = Post::selectFirst(['uri-id', 'author-id'], ['uri' => $activity['object_id']]);
 702                 if (empty($parent['uri-id'])) {
 703                         if (self::fetchMissingActivity($activity['object_id'], $activity, '', Receiver::COMPLETION_AUTO)) {
 704                                 $parent = Post::selectFirst(['uri-id'], ['uri' => $activity['object_id']]);
 705                         }
 706                 }
 707
 708                 if (!empty($parent['uri-id'])) {
 709                         $parent;
 710                 }
 711
 712                 return null;
 713         }
 714
 715         /**
 716          * Add a post to the "Featured" collection
 717          *
 718          * @param array $activity
 719          */
 720         public static function addToFeaturedCollection(array $activity)
 721         {
 722                 $post = self::getUriIdForFeaturedCollection($activity);
 723                 if (empty($post)) {
 724                         return;
 725                 }
 726
 727                 Logger::debug('Add post to featured collection', ['post' => $post]);
 728
 729                 Post\Collection::add($post['uri-id'], Post\Collection::FEATURED, $post['author-id']);
 730                 Queue::remove($activity);
 731         }
 732
 733         /**
 734          * Remove a post to the "Featured" collection
 735          *
 736          * @param array $activity
 737          */
 738         public static function removeFromFeaturedCollection(array $activity)
 739         {
 740                 $post = self::getUriIdForFeaturedCollection($activity);
 741                 if (empty($post)) {
 742                         return;
 743                 }
 744
 745                 Logger::debug('Remove post from featured collection', ['post' => $post]);
 746
 747                 Post\Collection::remove($post['uri-id'], Post\Collection::FEATURED);
 748                 Queue::remove($activity);
 749         }
 750
 751         /**
 752          * Create an event
 753          *
 754          * @param array $activity Activity array
 755          * @param array $item
 756          *
 757          * @return int event id
 758          * @throws \Exception
 759          */
 760         public static function createEvent(array $activity, array $item): int
 761         {
 762                 $event['summary']   = HTML::toBBCode($activity['name'] ?: $activity['summary']);
 763                 $event['desc']      = HTML::toBBCode($activity['content'] ?? '');
 764                 if (!empty($activity['start-time'])) {
 765                         $event['start']  = DateTimeFormat::utc($activity['start-time']);
 766                 }
 767                 if (!empty($activity['end-time'])) {
 768                         $event['finish'] = DateTimeFormat::utc($activity['end-time']);
 769                 }
 770                 $event['nofinish']  = empty($event['finish']);
 771                 $event['location']  = $activity['location'];
 772                 $event['cid']       = $item['contact-id'];
 773                 $event['uid']       = $item['uid'];
 774                 $event['uri']       = $item['uri'];
 775                 $event['edited']    = $item['edited'];
 776                 $event['private']   = $item['private'];
 777                 $event['guid']      = $item['guid'];
 778                 $event['plink']     = $item['plink'];
 779                 $event['network']   = $item['network'];
 780                 $event['protocol']  = $item['protocol'];
 781                 $event['direction'] = $item['direction'];
 782                 $event['source']    = $item['source'];
 783
 784                 $ev = DBA::selectFirst('event', ['id'], ['uri' => $item['uri'], 'uid' => $item['uid']]);
 785                 if (DBA::isResult($ev)) {
 786                         $event['id'] = $ev['id'];
 787                 }
 788
 789                 $event_id = Event::store($event);
 790
 791                 Logger::info('Event was stored', ['id' => $event_id]);
 792
 793                 return $event_id;
 794         }
 795
 796         /**
 797          * Process the content
 798          *
 799          * @param array $activity Activity array
 800          * @param array $item
 801          * @return array|bool Returns the item array or false if there was an unexpected occurrence
 802          * @throws \Exception
 803          */
 804         private static function processContent(array $activity, array $item)
 805         {
 806                 if (!empty($activity['mediatype']) && ($activity['mediatype'] == 'text/markdown')) {
 807                         $item['title'] = strip_tags($activity['name']);
 808                         $content = Markdown::toBBCode($activity['content']);
 809                 } elseif (!empty($activity['mediatype']) && ($activity['mediatype'] == 'text/bbcode')) {
 810                         $item['title'] = $activity['name'];
 811                         $content = $activity['content'];
 812                 } else {
 813                         // By default assume "text/html"
 814                         $item['title'] = HTML::toBBCode($activity['name'] ?? '');
 815                         $content = HTML::toBBCode($activity['content'] ?? '');
 816                 }
 817
 818                 $item['title'] = trim(BBCode::toPlaintext($item['title']));
 819
 820                 if (!empty($activity['languages'])) {
 821                         $item['language'] = self::processLanguages($activity['languages']);
 822                 }
 823
 824                 if (!empty($activity['emojis'])) {
 825                         $content = self::replaceEmojis($item['uri-id'], $content, $activity['emojis']);
 826                 }
 827
 828                 $content = self::addMentionLinks($content, $activity['tags']);
 829
 830                 if (!empty($activity['source'])) {
 831                         $item['body'] = $activity['source'];
 832                         $item['raw-body'] = $content;
 833                         $item['body'] = Item::improveSharedDataInBody($item);
 834                 } else {
 835                         $parent_uri = $item['parent-uri'] ?? $item['thr-parent'];
 836                         if (empty($activity['directmessage']) && ($parent_uri != $item['uri']) && ($item['gravity'] == GRAVITY_COMMENT)) {
 837                                 $parent = Post::selectFirst(['id', 'uri-id', 'private', 'author-link', 'alias'], ['uri' => $parent_uri]);
 838                                 if (!DBA::isResult($parent)) {
 839                                         Logger::warning('Unknown parent item.', ['uri' => $parent_uri]);
 840                                         return false;
 841                                 }
 842                                 if (!empty($activity['type']) && in_array($activity['type'], Receiver::CONTENT_TYPES) && ($item['private'] == Item::PRIVATE) && ($parent['private'] != Item::PRIVATE)) {
 843                                         Logger::warning('Item is private but the parent is not. Dropping.', ['item-uri' => $item['uri'], 'thr-parent' => $item['thr-parent']]);
 844                                         return false;
 845                                 }
 846
 847                                 $content = self::removeImplicitMentionsFromBody($content, $parent);
 848                         }
 849                         $item['content-warning'] = HTML::toBBCode($activity['summary'] ?? '');
 850                         $item['raw-body'] = $item['body'] = $content;
 851                 }
 852
 853                 self::storeFromBody($item);
 854                 self::storeTags($item['uri-id'], $activity['tags']);
 855
 856                 self::storeReceivers($item['uri-id'], $activity['receiver_urls'] ?? []);
 857
 858                 $item['location'] = $activity['location'];
 859
 860                 if (!empty($activity['latitude']) && !empty($activity['longitude'])) {
 861                         $item['coord'] = $activity['latitude'] . ' ' . $activity['longitude'];
 862                 }
 863
 864                 $item['app'] = $activity['generator'];
 865
 866                 return $item;
 867         }
 868
 869         /**
 870          * Store hashtags and mentions
 871          *
 872          * @param array $item
 873          */
 874         private static function storeFromBody(array $item)
 875         {
 876                 // Make sure to delete all existing tags (can happen when called via the update functionality)
 877                 DBA::delete('post-tag', ['uri-id' => $item['uri-id']]);
 878
 879                 Tag::storeFromBody($item['uri-id'], $item['body'], '@!');
 880         }
 881
 882         /**
 883          * Generate a GUID out of an URL of an ActivityPub post.
 884          *
 885          * @param string $url message URL
 886          * @return string with GUID
 887          */
 888         private static function getGUIDByURL(string $url): string
 889         {
 890                 $parsed = parse_url($url);
 891
 892                 $host_hash = hash('crc32', $parsed['host']);
 893
 894                 unset($parsed["scheme"]);
 895                 unset($parsed["host"]);
 896
 897                 $path = implode("/", $parsed);
 898
 899                 return $host_hash . '-'. hash('fnv164', $path) . '-'. hash('joaat', $path);
 900         }
 901
 902         /**
 903          * Checks if an incoming message is wanted
 904          *
 905          * @param array $activity
 906          * @param array $item
 907          * @return boolean Is the message wanted?
 908          */
 909         private static function isSolicitedMessage(array $activity, array $item): bool
 910         {
 911                 // The checks are split to improve the support when searching why a message was accepted.
 912                 if (count($activity['receiver']) != 1) {
 913                         // The message has more than one receiver, so it is wanted.
 914                         Logger::debug('Message has got several receivers - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 915                         return true;
 916                 }
 917
 918                 if ($item['private'] == Item::PRIVATE) {
 919                         // We only look at public posts here. Private posts are expected to be intentionally posted to the single receiver.
 920                         Logger::debug('Message is private - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 921                         return true;
 922                 }
 923
 924                 if (!empty($activity['from-relay'])) {
 925                         // We check relay posts at another place. When it arrived here, the message is already checked.
 926                         Logger::debug('Message is a relay post that is already checked - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 927                         return true;
 928                 }
 929
 930                 if (in_array($activity['completion-mode'] ?? Receiver::COMPLETION_NONE, [Receiver::COMPLETION_MANUAL, Receiver::COMPLETION_ANNOUCE])) {
 931                         // Manual completions and completions caused by reshares are allowed without any further checks.
 932                         Logger::debug('Message is in completion mode - accepted', ['mode' => $activity['completion-mode'], 'uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 933                         return true;
 934                 }
 935
 936                 if ($item['gravity'] != GRAVITY_PARENT) {
 937                         // We cannot reliably check at this point if a comment or activity belongs to an accepted post or needs to be fetched
 938                         // This can possibly be improved in the future.
 939                         Logger::debug('Message is no parent - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 940                         return true;
 941                 }
 942
 943                 $tags = array_column(Tag::getByURIId($item['uri-id'], [Tag::HASHTAG]), 'name');
 944                 if (Relay::isSolicitedPost($tags, $item['body'], $item['author-id'], $item['uri'], Protocol::ACTIVITYPUB)) {
 945                         Logger::debug('Post is accepted because of the relay settings', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 946                         return true;
 947                 } else {
 948                         return false;
 949                 }
 950         }
 951
 952         /**
 953          * Creates an item post
 954          *
 955          * @param array $activity Activity data
 956          * @param array $item     item array
 957          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 958          * @throws \ImagickException
 959          */
 960         public static function postItem(array $activity, array $item)
 961         {
 962                 if (empty($item)) {
 963                         return;
 964                 }
 965
 966                 $stored = false;
 967                 $success = false;
 968                 ksort($activity['receiver']);
 969
 970                 if (!self::isSolicitedMessage($activity, $item)) {
 971                         DBA::delete('item-uri', ['id' => $item['uri-id']]);
 972                         if (!empty($activity['entry-id'])) {
 973                                 Queue::deleteById($activity['entry-id']);
 974                         }
 975                         return;
 976                 }
 977
 978                 foreach ($activity['receiver'] as $receiver) {
 979                         if ($receiver == -1) {
 980                                 continue;
 981                         }
 982
 983                         $item['uid'] = $receiver;
 984
 985                         $type = $activity['reception_type'][$receiver] ?? Receiver::TARGET_UNKNOWN;
 986                         switch($type) {
 987                                 case Receiver::TARGET_TO:
 988                                         $item['post-reason'] = Item::PR_TO;
 989                                         break;
 990                                 case Receiver::TARGET_CC:
 991                                         $item['post-reason'] = Item::PR_CC;
 992                                         break;
 993                                 case Receiver::TARGET_BTO:
 994                                         $item['post-reason'] = Item::PR_BTO;
 995                                         break;
 996                                 case Receiver::TARGET_BCC:
 997                                         $item['post-reason'] = Item::PR_BCC;
 998                                         break;
 999                                 case Receiver::TARGET_FOLLOWER:
1000                                         $item['post-reason'] = Item::PR_FOLLOWER;
1001                                         break;
1002                                 case Receiver::TARGET_ANSWER:
1003                                         $item['post-reason'] = Item::PR_COMMENT;
1004                                         break;
1005                                 case Receiver::TARGET_GLOBAL:
1006                                         $item['post-reason'] = Item::PR_GLOBAL;
1007                                         break;
1008                                 default:
1009                                         $item['post-reason'] = Item::PR_NONE;
1010                         }
1011
1012                         $item['post-reason'] = Item::getPostReason($item);
1013
1014                         if (in_array($item['post-reason'], [Item::PR_GLOBAL, Item::PR_NONE])) {
1015                                 if (!empty($activity['from-relay'])) {
1016                                         $item['post-reason'] = Item::PR_RELAY;
1017                                 } elseif (!empty($activity['thread-completion'])) {
1018                                         $item['post-reason'] = Item::PR_FETCHED;
1019                                 } elseif (!empty($activity['push'])) {
1020                                         $item['post-reason'] = Item::PR_PUSHED;
1021                                 }
1022                         }
1023
1024                         if ($item['isForum'] ?? false) {
1025                                 $item['contact-id'] = Contact::getIdForURL($activity['actor'], $receiver);
1026                         } else {
1027                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver);
1028                         }
1029
1030                         if (($receiver != 0) && empty($item['contact-id'])) {
1031                                 $item['contact-id'] = Contact::getIdForURL($activity['author']);
1032                         }
1033
1034                         if (!empty($activity['directmessage'])) {
1035                                 self::postMail($activity, $item);
1036                                 continue;
1037                         }
1038
1039                         if (($receiver != 0) && ($item['gravity'] == GRAVITY_PARENT) && !in_array($item['post-reason'], [Item::PR_FOLLOWER, Item::PR_TAG, item::PR_TO, Item::PR_CC])) {
1040                                 if (!($item['isForum'] ?? false)) {
1041                                         if ($item['post-reason'] == Item::PR_BCC) {
1042                                                 Logger::info('Top level post via BCC from a non sharer, ignoring', ['uid' => $receiver, 'contact' => $item['contact-id'], 'url' => $item['uri']]);
1043                                                 continue;
1044                                         }
1045
1046                                         if ((DI::pConfig()->get($receiver, 'system', 'accept_only_sharer') != Item::COMPLETION_LIKE)
1047                                                 && in_array($activity['thread-children-type'] ?? '', Receiver::ACTIVITY_TYPES)) {
1048                                                 Logger::info('Top level post from thread completion from a non sharer had been initiated via an activity, ignoring',
1049                                                         ['type' => $activity['thread-children-type'], 'user' => $item['uid'], 'causer' => $item['causer-link'], 'author' => $activity['author'], 'url' => $item['uri']]);
1050                                                 continue;
1051                                         }
1052                                 }
1053
1054                                 $is_forum = false;
1055                                 $user = User::getById($receiver, ['account-type']);
1056                                 if (!empty($user['account-type'])) {
1057                                         $is_forum = ($user['account-type'] == User::ACCOUNT_TYPE_COMMUNITY);
1058                                 }
1059
1060                                 if ((DI::pConfig()->get($receiver, 'system', 'accept_only_sharer') == Item::COMPLETION_NONE)
1061                                         && ((!$is_forum && !($item['isForum'] ?? false) && ($activity['type'] != 'as:Announce'))
1062                                         || !Contact::isSharingByURL($activity['actor'], $receiver))) {
1063                                         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']]);
1064                                         continue;
1065                                 }
1066
1067                                 Logger::info('Accepting post', ['uid' => $receiver, 'url' => $item['uri']]);
1068                         }
1069
1070                         if (!self::hasParents($item, $receiver)) {
1071                                 continue;
1072                         }
1073
1074                         if (($item['gravity'] != GRAVITY_ACTIVITY) && ($activity['object_type'] == 'as:Event')) {
1075                                 $event_id = self::createEvent($activity, $item);
1076
1077                                 $item = Event::getItemArrayForImportedId($event_id, $item);
1078                         }
1079
1080                         $item_id = Item::insert($item);
1081                         if ($item_id) {
1082                                 Logger::info('Item insertion successful', ['user' => $item['uid'], 'item_id' => $item_id]);
1083                                 $success = true;
1084                         } else {
1085                                 Logger::notice('Item insertion aborted', ['uri' => $item['uri'], 'uid' => $item['uid']]);
1086                                 if (($item['uid'] == 0) && (count($activity['receiver']) > 1)) {
1087                                         Logger::info('Public item was aborted. We skip for all users.', ['uri' => $item['uri']]);
1088                                         break;
1089                                 }
1090                         }
1091
1092                         if ($item['uid'] == 0) {
1093                                 $stored = $item_id;
1094                         }
1095                 }
1096
1097                 Queue::remove($activity);
1098
1099                 if ($success && Queue::hasChildren($item['uri']) && Post::exists(['uri' => $item['uri']])) {
1100                         Queue::processReplyByUri($item['uri']);
1101                 }
1102
1103                 // Store send a follow request for every reshare - but only when the item had been stored
1104                 if ($stored && ($item['private'] != Item::PRIVATE) && ($item['gravity'] == GRAVITY_PARENT) && !empty($item['author-link']) && ($item['author-link'] != $item['owner-link'])) {
1105                         $author = APContact::getByURL($item['owner-link'], false);
1106                         // We send automatic follow requests for reshared messages. (We don't need though for forum posts)
1107                         if ($author['type'] != 'Group') {
1108                                 Logger::info('Send follow request', ['uri' => $item['uri'], 'stored' => $stored, 'to' => $item['author-link']]);
1109                                 ActivityPub\Transmitter::sendFollowObject($item['uri'], $item['author-link']);
1110                         }
1111                 }
1112         }
1113
1114         /**
1115          * Checks if there are parent posts for the given receiver.
1116          * If not, then the system will try to add them.
1117          *
1118          * @param array $item
1119          * @param integer $receiver
1120          * @return boolean
1121          */
1122         private static function hasParents(array $item, int $receiver)
1123         {
1124                 if (($receiver == 0) || ($item['gravity'] == GRAVITY_PARENT)) {
1125                         return true;
1126                 }
1127
1128                 $fields = ['causer-id' => $item['causer-id'] ?? $item['author-id'], 'post-reason' => Item::PR_FETCHED];
1129
1130                 $has_parents = false;
1131
1132                 if (!empty($item['parent-uri-id'])) {
1133                         if (Post::exists(['uri-id' => $item['parent-uri-id'], 'uid' => $receiver])) {
1134                                 $has_parents = true;
1135                         } elseif (Post::exists(['uri-id' => $item['parent-uri'], 'uid' => 0])) {
1136                                 $stored = Item::storeForUserByUriId($item['parent-uri-id'], $receiver, $fields);
1137                                 $has_parents = (bool)$stored;
1138                                 if ($stored) {
1139                                         Logger::notice('Inserted missing parent post', ['stored' => $stored, 'uid' => $receiver, 'parent' => $item['parent-uri']]);
1140                                 } else {
1141                                         Logger::notice('Parent could not be added.', ['uid' => $receiver, 'uri' => $item['uri'], 'parent' => $item['parent-uri']]);
1142                                         return false;
1143                                 }
1144                         }
1145                 }
1146
1147                 if (empty($item['parent-uri-id']) || ($item['thr-parent-id'] != $item['parent-uri-id'])) {
1148                         if (Post::exists(['uri-id' => $item['thr-parent-id'], 'uid' => $receiver])) {
1149                                 $has_parents = true;
1150                         } elseif (Post::exists(['uri-id' => $item['thr-parent-id'], 'uid' => 0])) {
1151                                 $stored = Item::storeForUserByUriId($item['thr-parent-id'], $receiver, $fields);
1152                                 $has_parents = $has_parents || (bool)$stored;
1153                                 if ($stored) {
1154                                         Logger::notice('Inserted missing thread parent post', ['stored' => $stored, 'uid' => $receiver, 'thread-parent' => $item['thr-parent']]);
1155                                 } else {
1156                                         Logger::notice('Thread parent could not be added.', ['uid' => $receiver, 'uri' => $item['uri'], 'thread-parent' => $item['thr-parent']]);
1157                                 }
1158                         }
1159                 }
1160
1161                 return $has_parents;
1162         }
1163
1164         /**
1165          * Store tags and mentions into the tag table
1166          *
1167          * @param integer $uriid
1168          * @param array $tags
1169          */
1170         private static function storeTags(int $uriid, array $tags = null)
1171         {
1172                 foreach ($tags as $tag) {
1173                         if (empty($tag['name']) || empty($tag['type']) || !in_array($tag['type'], ['Mention', 'Hashtag'])) {
1174                                 continue;
1175                         }
1176
1177                         $hash = substr($tag['name'], 0, 1);
1178
1179                         if ($tag['type'] == 'Mention') {
1180                                 if (in_array($hash, [Tag::TAG_CHARACTER[Tag::MENTION],
1181                                         Tag::TAG_CHARACTER[Tag::EXCLUSIVE_MENTION],
1182                                         Tag::TAG_CHARACTER[Tag::IMPLICIT_MENTION]])) {
1183                                         $tag['name'] = substr($tag['name'], 1);
1184                                 }
1185                                 $type = Tag::IMPLICIT_MENTION;
1186
1187                                 if (!empty($tag['href'])) {
1188                                         $apcontact = APContact::getByURL($tag['href']);
1189                                         if (!empty($apcontact['name']) || !empty($apcontact['nick'])) {
1190                                                 $tag['name'] = $apcontact['name'] ?: $apcontact['nick'];
1191                                         }
1192                                 }
1193                         } elseif ($tag['type'] == 'Hashtag') {
1194                                 if ($hash == Tag::TAG_CHARACTER[Tag::HASHTAG]) {
1195                                         $tag['name'] = substr($tag['name'], 1);
1196                                 }
1197                                 $type = Tag::HASHTAG;
1198                         }
1199
1200                         if (empty($tag['name'])) {
1201                                 continue;
1202                         }
1203
1204                         Tag::store($uriid, $type, $tag['name'], $tag['href']);
1205                 }
1206         }
1207
1208         public static function storeReceivers(int $uriid, array $receivers)
1209         {
1210                 foreach (['as:to' => Tag::TO, 'as:cc' => Tag::CC, 'as:bto' => Tag::BTO, 'as:bcc' => Tag::BCC] as $element => $type) {
1211                         if (!empty($receivers[$element])) {
1212                                 foreach ($receivers[$element] as $receiver) {
1213                                         if ($receiver == ActivityPub::PUBLIC_COLLECTION) {
1214                                                 $name = Receiver::PUBLIC_COLLECTION;
1215                                         } else {
1216                                                 $name = trim(parse_url($receiver, PHP_URL_PATH), '/');
1217                                         }
1218
1219                                         $target = Tag::getTargetType($receiver);
1220                                         Logger::debug('Got target type', ['type' => $target, 'url' => $receiver]);
1221                                         Tag::store($uriid, $type, $name, $receiver, $target);
1222                                 }
1223                         }
1224                 }
1225         }
1226
1227         /**
1228          * Creates an mail post
1229          *
1230          * @param array $activity Activity data
1231          * @param array $item     item array
1232          * @return int|bool New mail table row id or false on error
1233          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1234          */
1235         private static function postMail(array $activity, array $item)
1236         {
1237                 if (($item['gravity'] != GRAVITY_PARENT) && !DBA::exists('mail', ['uri' => $item['thr-parent'], 'uid' => $item['uid']])) {
1238                         Logger::info('Parent not found, mail will be discarded.', ['uid' => $item['uid'], 'uri' => $item['thr-parent']]);
1239                         return false;
1240                 }
1241
1242                 Logger::info('Direct Message', $item);
1243
1244                 $msg = [];
1245                 $msg['uid'] = $item['uid'];
1246
1247                 $msg['contact-id'] = $item['contact-id'];
1248
1249                 $contact = Contact::getById($item['contact-id'], ['name', 'url', 'photo']);
1250                 $msg['from-name'] = $contact['name'];
1251                 $msg['from-url'] = $contact['url'];
1252                 $msg['from-photo'] = $contact['photo'];
1253
1254                 $msg['uri'] = $item['uri'];
1255                 $msg['created'] = $item['created'];
1256
1257                 $parent = DBA::selectFirst('mail', ['parent-uri', 'title'], ['uri' => $item['thr-parent']]);
1258                 if (DBA::isResult($parent)) {
1259                         $msg['parent-uri'] = $parent['parent-uri'];
1260                         $msg['title'] = $parent['title'];
1261                 } else {
1262                         $msg['parent-uri'] = $item['thr-parent'];
1263
1264                         if (!empty($item['title'])) {
1265                                 $msg['title'] = $item['title'];
1266                         } elseif (!empty($item['content-warning'])) {
1267                                 $msg['title'] = $item['content-warning'];
1268                         } else {
1269                                 // Trying to generate a title out of the body
1270                                 $title = $item['body'];
1271
1272                                 while (preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $title, $matches)) {
1273                                         $title = $matches[3];
1274                                 }
1275
1276                                 $title = trim(BBCode::toPlaintext($title));
1277
1278                                 if (strlen($title) > 20) {
1279                                         $title = substr($title, 0, 20) . '...';
1280                                 }
1281
1282                                 $msg['title'] = $title;
1283                         }
1284                 }
1285                 $msg['body'] = $item['body'];
1286
1287                 return Mail::insert($msg);
1288         }
1289
1290         /**
1291          * Fetch featured posts from a contact with the given url
1292          *
1293          * @param string $url
1294          * @return void
1295          */
1296         public static function fetchFeaturedPosts(string $url)
1297         {
1298                 Logger::info('Fetch featured posts', ['contact' => $url]);
1299
1300                 $apcontact = APContact::getByURL($url);
1301                 if (empty($apcontact['featured'])) {
1302                         Logger::info('Contact does not have a featured collection', ['contact' => $url]);
1303                         return;
1304                 }
1305
1306                 $pcid = Contact::getIdForURL($url, 0, false);
1307                 if (empty($pcid)) {
1308                         Logger::notice('Contact not found', ['contact' => $url]);
1309                         return;
1310                 }
1311
1312                 $posts = Post\Collection::selectToArrayForContact($pcid, Post\Collection::FEATURED);
1313                 if (!empty($posts)) {
1314                         $old_featured = array_column($posts, 'uri-id');
1315                 } else {
1316                         $old_featured = [];
1317                 }
1318
1319                 $featured = ActivityPub::fetchItems($apcontact['featured']);
1320                 if (empty($featured)) {
1321                         Logger::info('Contact does not have featured posts', ['contact' => $url]);
1322
1323                         foreach ($old_featured as $uri_id) {
1324                                 Post\Collection::remove($uri_id, Post\Collection::FEATURED);
1325                                 Logger::debug('Removed no longer featured post', ['uri-id' => $uri_id, 'contact' => $url]);
1326                         }
1327                         return;
1328                 }
1329
1330                 $new = 0;
1331                 $old = 0;
1332
1333                 foreach ($featured as $post) {
1334                         if (empty($post['id'])) {
1335                                 continue;
1336                         }
1337                         $id = Item::fetchByLink($post['id']);
1338                         if (!empty($id)) {
1339                                 $item = Post::selectFirst(['uri-id', 'featured', 'author-id'], ['id' => $id]);
1340                                 if (!empty($item['uri-id'])) {
1341                                         if (!$item['featured']) {
1342                                                 Post\Collection::add($item['uri-id'], Post\Collection::FEATURED, $item['author-id']);
1343                                                 Logger::debug('Added featured post', ['uri-id' => $item['uri-id'], 'contact' => $url]);
1344                                                 $new++;
1345                                         } else {
1346                                                 Logger::debug('Post already had been featured', ['uri-id' => $item['uri-id'], 'contact' => $url]);
1347                                                 $old++;
1348                                         }
1349
1350                                         $index = array_search($item['uri-id'], $old_featured);
1351                                         if (!($index === false)) {
1352                                                 unset($old_featured[$index]);
1353                                         }
1354                                 }
1355                         }
1356                 }
1357
1358                 foreach ($old_featured as $uri_id) {
1359                         Post\Collection::remove($uri_id, Post\Collection::FEATURED);
1360                         Logger::debug('Removed no longer featured post', ['uri-id' => $uri_id, 'contact' => $url]);
1361                 }
1362
1363                 Logger::info('Fetched featured posts', ['new' => $new, 'old' => $old, 'contact' => $url]);
1364         }
1365
1366         public static function fetchCachedActivity(string $url, int $uid): array
1367         {
1368                 $cachekey = self::CACHEKEY_FETCH_ACTIVITY . $uid . ':' . hash('sha256', $url);
1369                 $object = DI::cache()->get($cachekey);
1370
1371                 if (!is_null($object)) {
1372                         if (!empty($object)) {
1373                                 Logger::debug('Fetch from cache', ['url' => $url, 'uid' => $uid]);
1374                         } else {
1375                                 Logger::debug('Fetch from negative cache', ['url' => $url, 'uid' => $uid]);
1376                         }
1377                         return $object;
1378                 }
1379
1380                 $object = ActivityPub::fetchContent($url, $uid);
1381                 if (empty($object)) {
1382                         Logger::notice('Activity was not fetchable, aborting.', ['url' => $url, 'uid' => $uid]);
1383                         // We perform negative caching.
1384                         DI::cache()->set($cachekey, [], Duration::FIVE_MINUTES);
1385                         return [];
1386                 }
1387
1388                 if (empty($object['id'])) {
1389                         Logger::notice('Activity has got not id, aborting. ', ['url' => $url, 'object' => $object]);
1390                         return [];
1391                 }
1392                 DI::cache()->set($cachekey, $object, Duration::FIVE_MINUTES);
1393
1394                 Logger::debug('Activity was fetched successfully', ['url' => $url, 'uid' => $uid]);
1395
1396                 return $object;
1397         }
1398
1399         /**
1400          * Fetches missing posts
1401          *
1402          * @param string     $url         message URL
1403          * @param array      $child       activity array with the child of this message
1404          * @param string     $relay_actor Relay actor
1405          * @param int        $completion  Completion mode, see Receiver::COMPLETION_*
1406          * @return string fetched message URL
1407          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1408          * @throws \ImagickException
1409          */
1410         public static function fetchMissingActivity(string $url, array $child = [], string $relay_actor = '', int $completion = Receiver::COMPLETION_MANUAL): string
1411         {
1412                 $object = self::fetchCachedActivity($url, 0);
1413                 if (empty($object)) {
1414                         return '';
1415                 }
1416
1417                 $signer = [];
1418
1419                 if (!empty($object['attributedTo'])) {
1420                         $attributed_to = $object['attributedTo'];
1421                         if (is_array($attributed_to)) {
1422                                 $compacted = JsonLD::compact($object);
1423                                 $attributed_to = JsonLD::fetchElement($compacted, 'as:attributedTo', '@id');
1424                         }
1425                         $signer[] = $attributed_to;
1426                 }
1427
1428                 if (!empty($object['actor'])) {
1429                         $object_actor = $object['actor'];
1430                 } elseif (!empty($attributed_to)) {
1431                         $object_actor = $attributed_to;
1432                 } else {
1433                         // Shouldn't happen
1434                         $object_actor = '';
1435                 }
1436
1437                 $signer[] = $object_actor;
1438
1439                 if (!empty($child['author'])) {
1440                         $actor = $child['author'];
1441                         $signer[] = $actor;
1442                 } else {
1443                         $actor = $object_actor;
1444                 }
1445
1446                 if (!empty($object['published'])) {
1447                         $published = $object['published'];
1448                 } elseif (!empty($child['published'])) {
1449                         $published = $child['published'];
1450                 } else {
1451                         $published = DateTimeFormat::utcNow();
1452                 }
1453
1454                 $activity = [];
1455                 $activity['@context'] = $object['@context'] ?? ActivityPub::CONTEXT;
1456                 unset($object['@context']);
1457                 $activity['id'] = $object['id'];
1458                 $activity['to'] = $object['to'] ?? [];
1459                 $activity['cc'] = $object['cc'] ?? [];
1460                 $activity['actor'] = $actor;
1461                 $activity['object'] = $object;
1462                 $activity['published'] = $published;
1463                 $activity['type'] = 'Create';
1464
1465                 $ldactivity = JsonLD::compact($activity);
1466
1467                 $ldactivity['recursion-depth'] = !empty($child['recursion-depth']) ? $child['recursion-depth'] + 1 : 0;
1468
1469                 if (!empty($relay_actor)) {
1470                         $ldactivity['thread-completion'] = $ldactivity['from-relay'] = Contact::getIdForURL($relay_actor);
1471                         $ldactivity['completion-mode']   = Receiver::COMPLETION_RELAY;
1472                 } elseif (!empty($child['thread-completion'])) {
1473                         $ldactivity['thread-completion'] = $child['thread-completion'];
1474                         $ldactivity['completion-mode']   = $child['completion-mode'] ?? Receiver::COMPLETION_NONE;
1475                 } else {
1476                         $ldactivity['thread-completion'] = Contact::getIdForURL($actor);
1477                         $ldactivity['completion-mode']   = $completion;
1478                 }
1479
1480                 if (!empty($child['thread-children-type'])) {
1481                         $ldactivity['thread-children-type'] = $child['thread-children-type'];
1482                 } elseif (!empty($child['type'])) {
1483                         $ldactivity['thread-children-type'] = $child['type'];
1484                 } else {
1485                         $ldactivity['thread-children-type'] = 'as:Create';
1486                 }
1487
1488                 if (!empty($relay_actor) && !self::acceptIncomingMessage($ldactivity, $object['id'])) {
1489                         return '';
1490                 }
1491
1492                 if (($completion == Receiver::COMPLETION_RELAY) && Queue::exists($url, 'as:Create')) {
1493                         Logger::notice('Activity has already been queued.', ['url' => $url, 'object' => $activity['id']]);
1494                 } elseif (ActivityPub\Receiver::processActivity($ldactivity, json_encode($activity), 0, true, false, $signer, '', $completion)) {
1495                         Logger::notice('Activity had been fetched and processed.', ['url' => $url, 'entry' => $child['entry-id'] ?? 0, 'completion' => $completion, 'object' => $activity['id']]);
1496                 } else {
1497                         Logger::notice('Activity had been fetched and will be processed later.', ['url' => $url, 'entry' => $child['entry-id'] ?? 0, 'completion' => $completion, 'object' => $activity['id']]);
1498                 }
1499
1500                 return $activity['id'];
1501         }
1502
1503         /**
1504          * Test if incoming relay messages should be accepted
1505          *
1506          * @param array $activity activity array
1507          * @param string $id      object ID
1508          * @return boolean true if message is accepted
1509          */
1510         private static function acceptIncomingMessage(array $activity, string $id): bool
1511         {
1512                 if (empty($activity['as:object'])) {
1513                         Logger::info('No object field in activity - accepted', ['id' => $id]);
1514                         return true;
1515                 }
1516
1517                 $replyto = JsonLD::fetchElement($activity['as:object'], 'as:inReplyTo', '@id');
1518                 $uriid = ItemURI::getIdByURI($replyto ?? '');
1519                 if (Post::exists(['uri-id' => $uriid])) {
1520                         Logger::info('Post is a reply to an existing post - accepted', ['id' => $id, 'uri-id' => $uriid, 'replyto' => $replyto]);
1521                         return true;
1522                 }
1523
1524                 $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
1525                 $authorid = Contact::getIdForURL($attributed_to);
1526
1527                 $body = HTML::toBBCode(JsonLD::fetchElement($activity['as:object'], 'as:content', '@value') ?? '');
1528
1529                 $messageTags = [];
1530                 $tags = Receiver::processTags(JsonLD::fetchElementArray($activity['as:object'], 'as:tag') ?? []);
1531                 if (!empty($tags)) {
1532                         foreach ($tags as $tag) {
1533                                 if ($tag['type'] != 'Hashtag') {
1534                                         continue;
1535                                 }
1536                                 $messageTags[] = ltrim(mb_strtolower($tag['name']), '#');
1537                         }
1538                 }
1539
1540                 return Relay::isSolicitedPost($messageTags, $body, $authorid, $id, Protocol::ACTIVITYPUB);
1541         }
1542
1543         /**
1544          * perform a "follow" request
1545          *
1546          * @param array $activity
1547          * @return void
1548          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1549          * @throws \ImagickException
1550          */
1551         public static function followUser(array $activity)
1552         {
1553                 $uid = User::getIdForURL($activity['object_id']);
1554                 if (empty($uid)) {
1555                         Queue::remove($activity);
1556                         return;
1557                 }
1558
1559                 $owner = User::getOwnerDataById($uid);
1560                 if (empty($owner)) {
1561                         return;
1562                 }
1563
1564                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1565                 if (!empty($cid)) {
1566                         self::switchContact($cid);
1567                         Contact::update(['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
1568                 }
1569
1570                 $item = [
1571                         'author-id' => Contact::getIdForURL($activity['actor']),
1572                         'author-link' => $activity['actor'],
1573                 ];
1574
1575                 // Ensure that the contact has got the right network type
1576                 self::switchContact($item['author-id']);
1577
1578                 $result = Contact::addRelationship($owner, [], $item, false, $activity['content'] ?? '');
1579                 if ($result === true) {
1580                         ActivityPub\Transmitter::sendContactAccept($item['author-link'], $activity['id'], $owner['uid']);
1581                 }
1582
1583                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1584                 if (empty($cid)) {
1585                         return;
1586                 }
1587
1588                 if ($result && DI::config()->get('system', 'transmit_pending_events') && ($owner['contact-type'] == Contact::TYPE_COMMUNITY)) {
1589                         self::transmitPendingEvents($cid, $owner['uid']);
1590                 }
1591
1592                 if (empty($contact)) {
1593                         Contact::update(['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
1594                 }
1595                 Logger::notice('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
1596                 Queue::remove($activity);
1597         }
1598
1599         /**
1600          * Transmit pending events to the new follower
1601          *
1602          * @param integer $cid Contact id
1603          * @param integer $uid User id
1604          * @return void
1605          */
1606         private static function transmitPendingEvents(int $cid, int $uid)
1607         {
1608                 $account = DBA::selectFirst('account-user-view', ['ap-inbox', 'ap-sharedinbox'], ['id' => $cid]);
1609                 $inbox = $account['ap-sharedinbox'] ?: $account['ap-inbox'];
1610
1611                 $events = DBA::select('event', ['id'], ["`uid` = ? AND `start` > ? AND `type` != ?", $uid, DateTimeFormat::utcNow(), 'birthday']);
1612                 while ($event = DBA::fetch($events)) {
1613                         $post = Post::selectFirst(['id', 'uri-id', 'created'], ['event-id' => $event['id']]);
1614                         if (empty($post)) {
1615                                 continue;
1616                         }
1617                         if (DI::config()->get('system', 'bulk_delivery')) {
1618                                 Post\Delivery::add($post['uri-id'], $uid, $inbox, $post['created'], Delivery::POST, [$cid]);
1619                                 Worker::add(PRIORITY_HIGH, 'APDelivery', '', 0, $inbox, 0);
1620                         } else {
1621                                 Worker::add(PRIORITY_HIGH, 'APDelivery', Delivery::POST, $post['id'], $inbox, $uid, [$cid], $post['uri-id']);
1622                         }
1623                 }
1624         }
1625
1626         /**
1627          * Update the given profile
1628          *
1629          * @param array $activity
1630          * @throws \Exception
1631          */
1632         public static function updatePerson(array $activity)
1633         {
1634                 if (empty($activity['object_id'])) {
1635                         return;
1636                 }
1637
1638                 Logger::info('Updating profile', ['object' => $activity['object_id']]);
1639                 Contact::updateFromProbeByURL($activity['object_id']);
1640                 Queue::remove($activity);
1641         }
1642
1643         /**
1644          * Delete the given profile
1645          *
1646          * @param array $activity
1647          * @return void
1648          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1649          */
1650         public static function deletePerson(array $activity)
1651         {
1652                 if (empty($activity['object_id']) || empty($activity['actor'])) {
1653                         Logger::info('Empty object id or actor.');
1654                         return;
1655                 }
1656
1657                 if ($activity['object_id'] != $activity['actor']) {
1658                         Logger::info('Object id does not match actor.');
1659                         return;
1660                 }
1661
1662                 $contacts = DBA::select('contact', ['id'], ['nurl' => Strings::normaliseLink($activity['object_id'])]);
1663                 while ($contact = DBA::fetch($contacts)) {
1664                         Contact::remove($contact['id']);
1665                 }
1666                 DBA::close($contacts);
1667
1668                 Logger::info('Deleted contact', ['object' => $activity['object_id']]);
1669                 Queue::remove($activity);
1670         }
1671
1672         /**
1673          * Blocks the user by the contact
1674          *
1675          * @param array $activity
1676          * @return void
1677          * @throws \Exception
1678          */
1679         public static function blockAccount(array $activity)
1680         {
1681                 $cid = Contact::getIdForURL($activity['actor']);
1682                 if (empty($cid)) {
1683                         return;
1684                 }
1685
1686                 $uid = User::getIdForURL($activity['object_id']);
1687                 if (empty($uid)) {
1688                         return;
1689                 }
1690
1691                 Contact\User::setIsBlocked($cid, $uid, true);
1692
1693                 Logger::info('Contact blocked user', ['contact' => $cid, 'user' => $uid]);
1694                 Queue::remove($activity);
1695         }
1696
1697         /**
1698          * Unblocks the user by the contact
1699          *
1700          * @param array $activity
1701          * @return void
1702          * @throws \Exception
1703          */
1704         public static function unblockAccount(array $activity)
1705         {
1706                 $cid = Contact::getIdForURL($activity['actor']);
1707                 if (empty($cid)) {
1708                         return;
1709                 }
1710
1711                 $uid = User::getIdForURL($activity['object_object']);
1712                 if (empty($uid)) {
1713                         return;
1714                 }
1715
1716                 Contact\User::setIsBlocked($cid, $uid, false);
1717
1718                 Logger::info('Contact unblocked user', ['contact' => $cid, 'user' => $uid]);
1719                 Queue::remove($activity);
1720         }
1721
1722         /**
1723          * Accept a follow request
1724          *
1725          * @param array $activity
1726          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1727          * @throws \ImagickException
1728          */
1729         public static function acceptFollowUser(array $activity)
1730         {
1731                 $uid = User::getIdForURL($activity['object_actor']);
1732                 if (empty($uid)) {
1733                         return;
1734                 }
1735
1736                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1737                 if (empty($cid)) {
1738                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1739                         return;
1740                 }
1741
1742                 self::switchContact($cid);
1743
1744                 $fields = ['pending' => false];
1745
1746                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
1747                 if ($contact['rel'] == Contact::FOLLOWER) {
1748                         $fields['rel'] = Contact::FRIEND;
1749                 }
1750
1751                 $condition = ['id' => $cid];
1752                 Contact::update($fields, $condition);
1753                 Logger::info('Accept contact request', ['contact' => $cid, 'user' => $uid]);
1754                 Queue::remove($activity);
1755         }
1756
1757         /**
1758          * Reject a follow request
1759          *
1760          * @param array $activity
1761          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1762          * @throws \ImagickException
1763          */
1764         public static function rejectFollowUser(array $activity)
1765         {
1766                 $uid = User::getIdForURL($activity['object_actor']);
1767                 if (empty($uid)) {
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                 $contact = Contact::getById($cid, ['rel']);
1780                 if ($contact['rel'] == Contact::SHARING) {
1781                         Contact::remove($cid);
1782                         Logger::info('Rejected contact request - contact removed', ['contact' => $cid, 'user' => $uid]);
1783                 } elseif ($contact['rel'] == Contact::FRIEND) {
1784                         Contact::update(['rel' => Contact::FOLLOWER], ['id' => $cid]);
1785                 } else {
1786                         Logger::info('Rejected contact request', ['contact' => $cid, 'user' => $uid]);
1787                 }
1788                 Queue::remove($activity);
1789         }
1790
1791         /**
1792          * Undo activity like "like" or "dislike"
1793          *
1794          * @param array $activity
1795          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1796          * @throws \ImagickException
1797          */
1798         public static function undoActivity(array $activity)
1799         {
1800                 if (empty($activity['object_id'])) {
1801                         return;
1802                 }
1803
1804                 if (empty($activity['object_actor'])) {
1805                         return;
1806                 }
1807
1808                 $author_id = Contact::getIdForURL($activity['object_actor']);
1809                 if (empty($author_id)) {
1810                         return;
1811                 }
1812
1813                 Item::markForDeletion(['uri' => $activity['object_id'], 'author-id' => $author_id, 'gravity' => GRAVITY_ACTIVITY]);
1814                 Queue::remove($activity);
1815         }
1816
1817         /**
1818          * Activity to remove a follower
1819          *
1820          * @param array $activity
1821          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1822          * @throws \ImagickException
1823          */
1824         public static function undoFollowUser(array $activity)
1825         {
1826                 $uid = User::getIdForURL($activity['object_object']);
1827                 if (empty($uid)) {
1828                         return;
1829                 }
1830
1831                 $owner = User::getOwnerDataById($uid);
1832                 if (empty($owner)) {
1833                         return;
1834                 }
1835
1836                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1837                 if (empty($cid)) {
1838                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1839                         return;
1840                 }
1841
1842                 self::switchContact($cid);
1843
1844                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1845                 if (!DBA::isResult($contact)) {
1846                         return;
1847                 }
1848
1849                 Contact::removeFollower($contact);
1850                 Logger::info('Undo following request', ['contact' => $cid, 'user' => $uid]);
1851                 Queue::remove($activity);
1852         }
1853
1854         /**
1855          * Switches a contact to AP if needed
1856          *
1857          * @param integer $cid Contact ID
1858          * @return void
1859          * @throws \Exception
1860          */
1861         private static function switchContact(int $cid)
1862         {
1863                 $contact = DBA::selectFirst('contact', ['network', 'url'], ['id' => $cid]);
1864                 if (!DBA::isResult($contact) || in_array($contact['network'], [Protocol::ACTIVITYPUB, Protocol::DFRN]) || Contact::isLocal($contact['url'])) {
1865                         return;
1866                 }
1867
1868                 Logger::info('Change existing contact', ['cid' => $cid, 'previous' => $contact['network']]);
1869                 Contact::updateFromProbe($cid);
1870         }
1871
1872         /**
1873          * Collects implicit mentions like:
1874          * - the author of the parent item
1875          * - all the mentioned conversants in the parent item
1876          *
1877          * @param array $parent Item array with at least ['id', 'author-link', 'alias']
1878          * @return array
1879          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1880          */
1881         private static function getImplicitMentionList(array $parent): array
1882         {
1883                 $parent_terms = Tag::getByURIId($parent['uri-id'], [Tag::MENTION, Tag::IMPLICIT_MENTION, Tag::EXCLUSIVE_MENTION]);
1884
1885                 $parent_author = Contact::getByURL($parent['author-link'], false, ['url', 'nurl', 'alias']);
1886
1887                 $implicit_mentions = [];
1888                 if (empty($parent_author['url'])) {
1889                         Logger::notice('Author public contact unknown.', ['author-link' => $parent['author-link'], 'parent-id' => $parent['id']]);
1890                 } else {
1891                         $implicit_mentions[] = $parent_author['url'];
1892                         $implicit_mentions[] = $parent_author['nurl'];
1893                         $implicit_mentions[] = $parent_author['alias'];
1894                 }
1895
1896                 if (!empty($parent['alias'])) {
1897                         $implicit_mentions[] = $parent['alias'];
1898                 }
1899
1900                 foreach ($parent_terms as $term) {
1901                         $contact = Contact::getByURL($term['url'], false, ['url', 'nurl', 'alias']);
1902                         if (!empty($contact['url'])) {
1903                                 $implicit_mentions[] = $contact['url'];
1904                                 $implicit_mentions[] = $contact['nurl'];
1905                                 $implicit_mentions[] = $contact['alias'];
1906                         }
1907                 }
1908
1909                 return $implicit_mentions;
1910         }
1911
1912         /**
1913          * Strips from the body prepended implicit mentions
1914          *
1915          * @param string $body
1916          * @param array $parent
1917          * @return string
1918          */
1919         private static function removeImplicitMentionsFromBody(string $body, array $parent): string
1920         {
1921                 if (DI::config()->get('system', 'disable_implicit_mentions')) {
1922                         return $body;
1923                 }
1924
1925                 $potential_mentions = self::getImplicitMentionList($parent);
1926
1927                 $kept_mentions = [];
1928
1929                 // Extract one prepended mention at a time from the body
1930                 while(preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $body, $matches)) {
1931                         if (!in_array($matches[2], $potential_mentions)) {
1932                                 $kept_mentions[] = $matches[1];
1933                         }
1934
1935                         $body = $matches[3];
1936                 }
1937
1938                 // Re-appending the kept mentions to the body after extraction
1939                 $kept_mentions[] = $body;
1940
1941                 return implode('', $kept_mentions);
1942         }
1943
1944         /**
1945          * Adds links to string mentions
1946          *
1947          * @param string $body
1948          * @param array  $tags
1949          * @return string
1950          */
1951         protected static function addMentionLinks(string $body, array $tags): string
1952         {
1953                 // This prevents links to be added again to Pleroma-style mention links
1954                 $body = self::normalizeMentionLinks($body);
1955
1956                 $body = BBCode::performWithEscapedTags($body, ['url'], function ($body) use ($tags) {
1957                         foreach ($tags as $tag) {
1958                                 if (empty($tag['name']) || empty($tag['type']) || empty($tag['href']) || !in_array($tag['type'], ['Mention', 'Hashtag'])) {
1959                                         continue;
1960                                 }
1961
1962                                 $hash = substr($tag['name'], 0, 1);
1963                                 $name = substr($tag['name'], 1);
1964                                 if (!in_array($hash, Tag::TAG_CHARACTER)) {
1965                                         $hash = '';
1966                                         $name = $tag['name'];
1967                                 }
1968
1969                                 $body = str_replace($tag['name'], $hash . '[url=' . $tag['href'] . ']' . $name . '[/url]', $body);
1970                         }
1971
1972                         return $body;
1973                 });
1974
1975                 return $body;
1976         }
1977 }