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         public 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'] = $content;
 851
 852                         if (!empty($activity['quote-url'])) {
 853                                 $item['body'] .= self::addSharedData($activity['quote-url']);
 854                         }
 855                 }
 856
 857                 self::storeFromBody($item);
 858                 self::storeTags($item['uri-id'], $activity['tags']);
 859
 860                 self::storeReceivers($item['uri-id'], $activity['receiver_urls'] ?? []);
 861
 862                 $item['location'] = $activity['location'];
 863
 864                 if (!empty($activity['latitude']) && !empty($activity['longitude'])) {
 865                         $item['coord'] = $activity['latitude'] . ' ' . $activity['longitude'];
 866                 }
 867
 868                 $item['app'] = $activity['generator'];
 869
 870                 return $item;
 871         }
 872
 873         /**
 874          * Add a share block for the given quote link
 875          *
 876          * @param string $url
 877          * @return string
 878          */
 879         private static function addSharedData(string $url): string
 880         {
 881                 $id = Item::fetchByLink($url);
 882                 if (empty($id)) {
 883                         return '';
 884                 }
 885
 886                 $shared_item = Post::selectFirst(['author-name', 'author-link', 'author-avatar', 'plink', 'created', 'guid', 'title', 'body'], ['id' => $id]);
 887                 if (!DBA::isResult($shared_item)) {
 888                         return '';
 889                 }
 890
 891                 $prefix = BBCode::getShareOpeningTag(
 892                         $shared_item['author-name'],
 893                         $shared_item['author-link'],
 894                         $shared_item['author-avatar'],
 895                         $shared_item['plink'],
 896                         $shared_item['created'],
 897                         $shared_item['guid']
 898                 );
 899
 900                 if (!empty($shared_item['title'])) {
 901                         $prefix .= '[h3]' . $shared_item['title'] . "[/h3]\n";
 902                 }
 903
 904                 return $prefix . $shared_item['body'] . '[/share]';
 905         }
 906
 907         /**
 908          * Store hashtags and mentions
 909          *
 910          * @param array $item
 911          */
 912         private static function storeFromBody(array $item)
 913         {
 914                 // Make sure to delete all existing tags (can happen when called via the update functionality)
 915                 DBA::delete('post-tag', ['uri-id' => $item['uri-id']]);
 916
 917                 Tag::storeFromBody($item['uri-id'], $item['body'], '@!');
 918         }
 919
 920         /**
 921          * Generate a GUID out of an URL of an ActivityPub post.
 922          *
 923          * @param string $url message URL
 924          * @return string with GUID
 925          */
 926         private static function getGUIDByURL(string $url): string
 927         {
 928                 $parsed = parse_url($url);
 929
 930                 $host_hash = hash('crc32', $parsed['host']);
 931
 932                 unset($parsed["scheme"]);
 933                 unset($parsed["host"]);
 934
 935                 $path = implode("/", $parsed);
 936
 937                 return $host_hash . '-'. hash('fnv164', $path) . '-'. hash('joaat', $path);
 938         }
 939
 940         /**
 941          * Checks if an incoming message is wanted
 942          *
 943          * @param array $activity
 944          * @param array $item
 945          * @return boolean Is the message wanted?
 946          */
 947         private static function isSolicitedMessage(array $activity, array $item): bool
 948         {
 949                 // The checks are split to improve the support when searching why a message was accepted.
 950                 if (count($activity['receiver']) != 1) {
 951                         // The message has more than one receiver, so it is wanted.
 952                         Logger::debug('Message has got several receivers - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 953                         return true;
 954                 }
 955
 956                 if ($item['private'] == Item::PRIVATE) {
 957                         // We only look at public posts here. Private posts are expected to be intentionally posted to the single receiver.
 958                         Logger::debug('Message is private - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 959                         return true;
 960                 }
 961
 962                 if (!empty($activity['from-relay'])) {
 963                         // We check relay posts at another place. When it arrived here, the message is already checked.
 964                         Logger::debug('Message is a relay post that is already checked - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 965                         return true;
 966                 }
 967
 968                 if (in_array($activity['completion-mode'] ?? Receiver::COMPLETION_NONE, [Receiver::COMPLETION_MANUAL, Receiver::COMPLETION_ANNOUCE])) {
 969                         // Manual completions and completions caused by reshares are allowed without any further checks.
 970                         Logger::debug('Message is in completion mode - accepted', ['mode' => $activity['completion-mode'], 'uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 971                         return true;
 972                 }
 973
 974                 if ($item['gravity'] != GRAVITY_PARENT) {
 975                         // We cannot reliably check at this point if a comment or activity belongs to an accepted post or needs to be fetched
 976                         // This can possibly be improved in the future.
 977                         Logger::debug('Message is no parent - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 978                         return true;
 979                 }
 980
 981                 $tags = array_column(Tag::getByURIId($item['uri-id'], [Tag::HASHTAG]), 'name');
 982                 if (Relay::isSolicitedPost($tags, $item['body'], $item['author-id'], $item['uri'], Protocol::ACTIVITYPUB)) {
 983                         Logger::debug('Post is accepted because of the relay settings', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 984                         return true;
 985                 } else {
 986                         return false;
 987                 }
 988         }
 989
 990         /**
 991          * Creates an item post
 992          *
 993          * @param array $activity Activity data
 994          * @param array $item     item array
 995          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 996          * @throws \ImagickException
 997          */
 998         public static function postItem(array $activity, array $item)
 999         {
1000                 if (empty($item)) {
1001                         return;
1002                 }
1003
1004                 $stored = false;
1005                 $success = false;
1006                 ksort($activity['receiver']);
1007
1008                 if (!self::isSolicitedMessage($activity, $item)) {
1009                         DBA::delete('item-uri', ['id' => $item['uri-id']]);
1010                         if (!empty($activity['entry-id'])) {
1011                                 Queue::deleteById($activity['entry-id']);
1012                         }
1013                         return;
1014                 }
1015
1016                 foreach ($activity['receiver'] as $receiver) {
1017                         if ($receiver == -1) {
1018                                 continue;
1019                         }
1020
1021                         if (($receiver != 0) && empty($item['parent-uri-id']) && !empty($item['thr-parent-id'])) {
1022                                 $parent = Post::selectFirst(['parent-uri-id', 'parent-uri'], ['uri-id' => $item['thr-parent-id'], 'uid' => [0, $receiver]]);
1023                                 if (!empty($parent['parent-uri-id'])) {
1024                                         $item['parent-uri-id'] = $parent['parent-uri-id'];
1025                                         $item['parent-uri']    = $parent['parent-uri'];
1026                                 }
1027                         }
1028
1029                         $item['uid'] = $receiver;
1030
1031                         $type = $activity['reception_type'][$receiver] ?? Receiver::TARGET_UNKNOWN;
1032                         switch($type) {
1033                                 case Receiver::TARGET_TO:
1034                                         $item['post-reason'] = Item::PR_TO;
1035                                         break;
1036                                 case Receiver::TARGET_CC:
1037                                         $item['post-reason'] = Item::PR_CC;
1038                                         break;
1039                                 case Receiver::TARGET_BTO:
1040                                         $item['post-reason'] = Item::PR_BTO;
1041                                         break;
1042                                 case Receiver::TARGET_BCC:
1043                                         $item['post-reason'] = Item::PR_BCC;
1044                                         break;
1045                                 case Receiver::TARGET_FOLLOWER:
1046                                         $item['post-reason'] = Item::PR_FOLLOWER;
1047                                         break;
1048                                 case Receiver::TARGET_ANSWER:
1049                                         $item['post-reason'] = Item::PR_COMMENT;
1050                                         break;
1051                                 case Receiver::TARGET_GLOBAL:
1052                                         $item['post-reason'] = Item::PR_GLOBAL;
1053                                         break;
1054                                 default:
1055                                         $item['post-reason'] = Item::PR_NONE;
1056                         }
1057
1058                         $item['post-reason'] = Item::getPostReason($item);
1059
1060                         if (in_array($item['post-reason'], [Item::PR_GLOBAL, Item::PR_NONE])) {
1061                                 if (!empty($activity['from-relay'])) {
1062                                         $item['post-reason'] = Item::PR_RELAY;
1063                                 } elseif (!empty($activity['thread-completion'])) {
1064                                         $item['post-reason'] = Item::PR_FETCHED;
1065                                 } elseif (!empty($activity['push'])) {
1066                                         $item['post-reason'] = Item::PR_PUSHED;
1067                                 }
1068                         } elseif (($item['post-reason'] == Item::PR_FOLLOWER) && !empty($activity['from-relay'])) {
1069                                 // When a post arrives via a relay and we follow the author, we have to override the causer.
1070                                 // Otherwise the system assumes that we follow the relay. (See "addRowInformation")
1071                                 Logger::debug('Relay post for follower', ['receiver' => $receiver, 'guid' => $item['guid'], 'relay' => $activity['from-relay']]);
1072                                 $item['causer-id'] = ($item['gravity'] == GRAVITY_PARENT) ? $item['owner-id'] : $item['author-id'];
1073                         }
1074
1075                         if ($item['isForum'] ?? false) {
1076                                 $item['contact-id'] = Contact::getIdForURL($activity['actor'], $receiver);
1077                         } else {
1078                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver);
1079                         }
1080
1081                         if (($receiver != 0) && empty($item['contact-id'])) {
1082                                 $item['contact-id'] = Contact::getIdForURL($activity['author']);
1083                         }
1084
1085                         if (!empty($activity['directmessage'])) {
1086                                 self::postMail($activity, $item);
1087                                 continue;
1088                         }
1089
1090                         if (($receiver != 0) && ($item['gravity'] == GRAVITY_PARENT) && !in_array($item['post-reason'], [Item::PR_FOLLOWER, Item::PR_TAG, item::PR_TO, Item::PR_CC])) {
1091                                 if (!($item['isForum'] ?? false)) {
1092                                         if ($item['post-reason'] == Item::PR_BCC) {
1093                                                 Logger::info('Top level post via BCC from a non sharer, ignoring', ['uid' => $receiver, 'contact' => $item['contact-id'], 'url' => $item['uri']]);
1094                                                 continue;
1095                                         }
1096
1097                                         if ((DI::pConfig()->get($receiver, 'system', 'accept_only_sharer') != Item::COMPLETION_LIKE)
1098                                                 && in_array($activity['thread-children-type'] ?? '', Receiver::ACTIVITY_TYPES)) {
1099                                                 Logger::info('Top level post from thread completion from a non sharer had been initiated via an activity, ignoring',
1100                                                         ['type' => $activity['thread-children-type'], 'user' => $item['uid'], 'causer' => $item['causer-link'], 'author' => $activity['author'], 'url' => $item['uri']]);
1101                                                 continue;
1102                                         }
1103                                 }
1104
1105                                 $is_forum = false;
1106                                 $user = User::getById($receiver, ['account-type']);
1107                                 if (!empty($user['account-type'])) {
1108                                         $is_forum = ($user['account-type'] == User::ACCOUNT_TYPE_COMMUNITY);
1109                                 }
1110
1111                                 if ((DI::pConfig()->get($receiver, 'system', 'accept_only_sharer') == Item::COMPLETION_NONE)
1112                                         && ((!$is_forum && !($item['isForum'] ?? false) && ($activity['type'] != 'as:Announce'))
1113                                         || !Contact::isSharingByURL($activity['actor'], $receiver))) {
1114                                         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']]);
1115                                         continue;
1116                                 }
1117
1118                                 Logger::info('Accepting post', ['uid' => $receiver, 'url' => $item['uri']]);
1119                         }
1120
1121                         if (!self::hasParents($item, $receiver)) {
1122                                 continue;
1123                         }
1124
1125                         if (($item['gravity'] != GRAVITY_ACTIVITY) && ($activity['object_type'] == 'as:Event')) {
1126                                 $event_id = self::createEvent($activity, $item);
1127
1128                                 $item = Event::getItemArrayForImportedId($event_id, $item);
1129                         }
1130
1131                         $item_id = Item::insert($item);
1132                         if ($item_id) {
1133                                 Logger::info('Item insertion successful', ['user' => $item['uid'], 'item_id' => $item_id]);
1134                                 $success = true;
1135                         } else {
1136                                 Logger::notice('Item insertion aborted', ['uri' => $item['uri'], 'uid' => $item['uid']]);
1137                                 if (($item['uid'] == 0) && (count($activity['receiver']) > 1)) {
1138                                         Logger::info('Public item was aborted. We skip for all users.', ['uri' => $item['uri']]);
1139                                         break;
1140                                 }
1141                         }
1142
1143                         if ($item['uid'] == 0) {
1144                                 $stored = $item_id;
1145                         }
1146                 }
1147
1148                 Queue::remove($activity);
1149
1150                 if ($success && Queue::hasChildren($item['uri']) && Post::exists(['uri' => $item['uri']])) {
1151                         Queue::processReplyByUri($item['uri']);
1152                 }
1153
1154                 // Store send a follow request for every reshare - but only when the item had been stored
1155                 if ($stored && ($item['private'] != Item::PRIVATE) && ($item['gravity'] == GRAVITY_PARENT) && !empty($item['author-link']) && ($item['author-link'] != $item['owner-link'])) {
1156                         $author = APContact::getByURL($item['owner-link'], false);
1157                         // We send automatic follow requests for reshared messages. (We don't need though for forum posts)
1158                         if ($author['type'] != 'Group') {
1159                                 Logger::info('Send follow request', ['uri' => $item['uri'], 'stored' => $stored, 'to' => $item['author-link']]);
1160                                 ActivityPub\Transmitter::sendFollowObject($item['uri'], $item['author-link']);
1161                         }
1162                 }
1163         }
1164
1165         /**
1166          * Checks if there are parent posts for the given receiver.
1167          * If not, then the system will try to add them.
1168          *
1169          * @param array $item
1170          * @param integer $receiver
1171          * @return boolean
1172          */
1173         private static function hasParents(array $item, int $receiver)
1174         {
1175                 if (($receiver == 0) || ($item['gravity'] == GRAVITY_PARENT)) {
1176                         return true;
1177                 }
1178
1179                 $fields = ['causer-id' => $item['causer-id'] ?? $item['author-id'], 'post-reason' => Item::PR_FETCHED];
1180
1181                 $add_parent = true;
1182
1183                 if ($item['verb'] != Activity::ANNOUNCE) {
1184                         switch (DI::pConfig()->get($receiver, 'system', 'accept_only_sharer')) {
1185                                 case Item::COMPLETION_COMMENT:
1186                                         $add_parent = ($item['gravity'] != GRAVITY_ACTIVITY);
1187                                         break;
1188
1189                                 case Item::COMPLETION_NONE:
1190                                         $add_parent = false;
1191                                         break;
1192                         }
1193                 }
1194
1195                 if ($add_parent) {
1196                         $add_parent = Contact::isSharing($fields['causer-id'], $receiver);
1197                         if (!$add_parent && ($item['author-id'] != $fields['causer-id'])) {
1198                                 $add_parent = Contact::isSharing($item['author-id'], $receiver);
1199                         }
1200                         if (!$add_parent && !in_array($item['owner-id'], [$fields['causer-id'], $item['author-id']])) {
1201                                 $add_parent = Contact::isSharing($item['owner-id'], $receiver);
1202                         }
1203                 }
1204
1205                 $has_parents = false;
1206
1207                 if (!empty($item['parent-uri-id'])) {
1208                         if (Post::exists(['uri-id' => $item['parent-uri-id'], 'uid' => $receiver])) {
1209                                 $has_parents = true;
1210                         } elseif ($add_parent && Post::exists(['uri-id' => $item['parent-uri'], 'uid' => 0])) {
1211                                 $stored = Item::storeForUserByUriId($item['parent-uri-id'], $receiver, $fields);
1212                                 $has_parents = (bool)$stored;
1213                                 if ($stored) {
1214                                         Logger::notice('Inserted missing parent post', ['stored' => $stored, 'uid' => $receiver, 'parent' => $item['parent-uri']]);
1215                                 } else {
1216                                         Logger::notice('Parent could not be added.', ['uid' => $receiver, 'uri' => $item['uri'], 'parent' => $item['parent-uri']]);
1217                                         return false;
1218                                 }
1219                         } elseif ($add_parent) {
1220                                 Logger::debug('Parent does not exist.', ['uid' => $receiver, 'uri' => $item['uri'], 'parent' => $item['parent-uri']]);
1221                         } else {
1222                                 Logger::debug('Parent should not be added.', ['uid' => $receiver, 'gravity' => $item['gravity'], 'verb' => $item['verb'], 'guid' => $item['guid'], 'uri' => $item['uri'], 'parent' => $item['parent-uri']]);
1223                         }
1224                 }
1225
1226                 if (empty($item['parent-uri-id']) || ($item['thr-parent-id'] != $item['parent-uri-id'])) {
1227                         if (Post::exists(['uri-id' => $item['thr-parent-id'], 'uid' => $receiver])) {
1228                                 $has_parents = true;
1229                         } elseif (($has_parents || $add_parent) && Post::exists(['uri-id' => $item['thr-parent-id'], 'uid' => 0])) {
1230                                 $stored = Item::storeForUserByUriId($item['thr-parent-id'], $receiver, $fields);
1231                                 $has_parents = $has_parents || (bool)$stored;
1232                                 if ($stored) {
1233                                         Logger::notice('Inserted missing thread parent post', ['stored' => $stored, 'uid' => $receiver, 'thread-parent' => $item['thr-parent']]);
1234                                 } else {
1235                                         Logger::notice('Thread parent could not be added.', ['uid' => $receiver, 'uri' => $item['uri'], 'thread-parent' => $item['thr-parent']]);
1236                                 }
1237                         } elseif ($add_parent) {
1238                                 Logger::debug('Thread parent does not exist.', ['uid' => $receiver, 'uri' => $item['uri'], 'thread-parent' => $item['thr-parent']]);
1239                         } else {
1240                                 Logger::debug('Thread parent should not be added.', ['uid' => $receiver, 'gravity' => $item['gravity'], 'verb' => $item['verb'], 'guid' => $item['guid'], 'uri' => $item['uri'], 'thread-parent' => $item['thr-parent']]);
1241                         }
1242                 }
1243
1244                 return $has_parents;
1245         }
1246
1247         /**
1248          * Store tags and mentions into the tag table
1249          *
1250          * @param integer $uriid
1251          * @param array $tags
1252          */
1253         private static function storeTags(int $uriid, array $tags = null)
1254         {
1255                 foreach ($tags as $tag) {
1256                         if (empty($tag['name']) || empty($tag['type']) || !in_array($tag['type'], ['Mention', 'Hashtag'])) {
1257                                 continue;
1258                         }
1259
1260                         $hash = substr($tag['name'], 0, 1);
1261
1262                         if ($tag['type'] == 'Mention') {
1263                                 if (in_array($hash, [Tag::TAG_CHARACTER[Tag::MENTION],
1264                                         Tag::TAG_CHARACTER[Tag::EXCLUSIVE_MENTION],
1265                                         Tag::TAG_CHARACTER[Tag::IMPLICIT_MENTION]])) {
1266                                         $tag['name'] = substr($tag['name'], 1);
1267                                 }
1268                                 $type = Tag::IMPLICIT_MENTION;
1269
1270                                 if (!empty($tag['href'])) {
1271                                         $apcontact = APContact::getByURL($tag['href']);
1272                                         if (!empty($apcontact['name']) || !empty($apcontact['nick'])) {
1273                                                 $tag['name'] = $apcontact['name'] ?: $apcontact['nick'];
1274                                         }
1275                                 }
1276                         } elseif ($tag['type'] == 'Hashtag') {
1277                                 if ($hash == Tag::TAG_CHARACTER[Tag::HASHTAG]) {
1278                                         $tag['name'] = substr($tag['name'], 1);
1279                                 }
1280                                 $type = Tag::HASHTAG;
1281                         }
1282
1283                         if (empty($tag['name'])) {
1284                                 continue;
1285                         }
1286
1287                         Tag::store($uriid, $type, $tag['name'], $tag['href']);
1288                 }
1289         }
1290
1291         public static function storeReceivers(int $uriid, array $receivers)
1292         {
1293                 foreach (['as:to' => Tag::TO, 'as:cc' => Tag::CC, 'as:bto' => Tag::BTO, 'as:bcc' => Tag::BCC] as $element => $type) {
1294                         if (!empty($receivers[$element])) {
1295                                 foreach ($receivers[$element] as $receiver) {
1296                                         if ($receiver == ActivityPub::PUBLIC_COLLECTION) {
1297                                                 $name = Receiver::PUBLIC_COLLECTION;
1298                                         } else {
1299                                                 $name = trim(parse_url($receiver, PHP_URL_PATH), '/');
1300                                         }
1301
1302                                         $target = Tag::getTargetType($receiver);
1303                                         Logger::debug('Got target type', ['type' => $target, 'url' => $receiver]);
1304                                         Tag::store($uriid, $type, $name, $receiver, $target);
1305                                 }
1306                         }
1307                 }
1308         }
1309
1310         /**
1311          * Creates an mail post
1312          *
1313          * @param array $activity Activity data
1314          * @param array $item     item array
1315          * @return int|bool New mail table row id or false on error
1316          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1317          */
1318         private static function postMail(array $activity, array $item)
1319         {
1320                 if (($item['gravity'] != GRAVITY_PARENT) && !DBA::exists('mail', ['uri' => $item['thr-parent'], 'uid' => $item['uid']])) {
1321                         Logger::info('Parent not found, mail will be discarded.', ['uid' => $item['uid'], 'uri' => $item['thr-parent']]);
1322                         return false;
1323                 }
1324
1325                 Logger::info('Direct Message', $item);
1326
1327                 $msg = [];
1328                 $msg['uid'] = $item['uid'];
1329
1330                 $msg['contact-id'] = $item['contact-id'];
1331
1332                 $contact = Contact::getById($item['contact-id'], ['name', 'url', 'photo']);
1333                 $msg['from-name'] = $contact['name'];
1334                 $msg['from-url'] = $contact['url'];
1335                 $msg['from-photo'] = $contact['photo'];
1336
1337                 $msg['uri'] = $item['uri'];
1338                 $msg['created'] = $item['created'];
1339
1340                 $parent = DBA::selectFirst('mail', ['parent-uri', 'title'], ['uri' => $item['thr-parent']]);
1341                 if (DBA::isResult($parent)) {
1342                         $msg['parent-uri'] = $parent['parent-uri'];
1343                         $msg['title'] = $parent['title'];
1344                 } else {
1345                         $msg['parent-uri'] = $item['thr-parent'];
1346
1347                         if (!empty($item['title'])) {
1348                                 $msg['title'] = $item['title'];
1349                         } elseif (!empty($item['content-warning'])) {
1350                                 $msg['title'] = $item['content-warning'];
1351                         } else {
1352                                 // Trying to generate a title out of the body
1353                                 $title = $item['body'];
1354
1355                                 while (preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $title, $matches)) {
1356                                         $title = $matches[3];
1357                                 }
1358
1359                                 $title = trim(BBCode::toPlaintext($title));
1360
1361                                 if (strlen($title) > 20) {
1362                                         $title = substr($title, 0, 20) . '...';
1363                                 }
1364
1365                                 $msg['title'] = $title;
1366                         }
1367                 }
1368                 $msg['body'] = $item['body'];
1369
1370                 return Mail::insert($msg);
1371         }
1372
1373         /**
1374          * Fetch featured posts from a contact with the given url
1375          *
1376          * @param string $url
1377          * @return void
1378          */
1379         public static function fetchFeaturedPosts(string $url)
1380         {
1381                 Logger::info('Fetch featured posts', ['contact' => $url]);
1382
1383                 $apcontact = APContact::getByURL($url);
1384                 if (empty($apcontact['featured'])) {
1385                         Logger::info('Contact does not have a featured collection', ['contact' => $url]);
1386                         return;
1387                 }
1388
1389                 $pcid = Contact::getIdForURL($url, 0, false);
1390                 if (empty($pcid)) {
1391                         Logger::notice('Contact not found', ['contact' => $url]);
1392                         return;
1393                 }
1394
1395                 $posts = Post\Collection::selectToArrayForContact($pcid, Post\Collection::FEATURED);
1396                 if (!empty($posts)) {
1397                         $old_featured = array_column($posts, 'uri-id');
1398                 } else {
1399                         $old_featured = [];
1400                 }
1401
1402                 $featured = ActivityPub::fetchItems($apcontact['featured']);
1403                 if (empty($featured)) {
1404                         Logger::info('Contact does not have featured posts', ['contact' => $url]);
1405
1406                         foreach ($old_featured as $uri_id) {
1407                                 Post\Collection::remove($uri_id, Post\Collection::FEATURED);
1408                                 Logger::debug('Removed no longer featured post', ['uri-id' => $uri_id, 'contact' => $url]);
1409                         }
1410                         return;
1411                 }
1412
1413                 $new = 0;
1414                 $old = 0;
1415
1416                 foreach ($featured as $post) {
1417                         if (empty($post['id'])) {
1418                                 continue;
1419                         }
1420                         $id = Item::fetchByLink($post['id']);
1421                         if (!empty($id)) {
1422                                 $item = Post::selectFirst(['uri-id', 'featured', 'author-id'], ['id' => $id]);
1423                                 if (!empty($item['uri-id'])) {
1424                                         if (!$item['featured']) {
1425                                                 Post\Collection::add($item['uri-id'], Post\Collection::FEATURED, $item['author-id']);
1426                                                 Logger::debug('Added featured post', ['uri-id' => $item['uri-id'], 'contact' => $url]);
1427                                                 $new++;
1428                                         } else {
1429                                                 Logger::debug('Post already had been featured', ['uri-id' => $item['uri-id'], 'contact' => $url]);
1430                                                 $old++;
1431                                         }
1432
1433                                         $index = array_search($item['uri-id'], $old_featured);
1434                                         if (!($index === false)) {
1435                                                 unset($old_featured[$index]);
1436                                         }
1437                                 }
1438                         }
1439                 }
1440
1441                 foreach ($old_featured as $uri_id) {
1442                         Post\Collection::remove($uri_id, Post\Collection::FEATURED);
1443                         Logger::debug('Removed no longer featured post', ['uri-id' => $uri_id, 'contact' => $url]);
1444                 }
1445
1446                 Logger::info('Fetched featured posts', ['new' => $new, 'old' => $old, 'contact' => $url]);
1447         }
1448
1449         public static function fetchCachedActivity(string $url, int $uid): array
1450         {
1451                 $cachekey = self::CACHEKEY_FETCH_ACTIVITY . $uid . ':' . hash('sha256', $url);
1452                 $object = DI::cache()->get($cachekey);
1453
1454                 if (!is_null($object)) {
1455                         if (!empty($object)) {
1456                                 Logger::debug('Fetch from cache', ['url' => $url, 'uid' => $uid]);
1457                         } else {
1458                                 Logger::debug('Fetch from negative cache', ['url' => $url, 'uid' => $uid]);
1459                         }
1460                         return $object;
1461                 }
1462
1463                 $object = ActivityPub::fetchContent($url, $uid);
1464                 if (empty($object)) {
1465                         Logger::notice('Activity was not fetchable, aborting.', ['url' => $url, 'uid' => $uid]);
1466                         // We perform negative caching.
1467                         DI::cache()->set($cachekey, [], Duration::FIVE_MINUTES);
1468                         return [];
1469                 }
1470
1471                 if (empty($object['id'])) {
1472                         Logger::notice('Activity has got not id, aborting. ', ['url' => $url, 'object' => $object]);
1473                         return [];
1474                 }
1475                 DI::cache()->set($cachekey, $object, Duration::FIVE_MINUTES);
1476
1477                 Logger::debug('Activity was fetched successfully', ['url' => $url, 'uid' => $uid]);
1478
1479                 return $object;
1480         }
1481
1482         /**
1483          * Fetches missing posts
1484          *
1485          * @param string     $url         message URL
1486          * @param array      $child       activity array with the child of this message
1487          * @param string     $relay_actor Relay actor
1488          * @param int        $completion  Completion mode, see Receiver::COMPLETION_*
1489          * @return string fetched message URL
1490          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1491          * @throws \ImagickException
1492          */
1493         public static function fetchMissingActivity(string $url, array $child = [], string $relay_actor = '', int $completion = Receiver::COMPLETION_MANUAL): string
1494         {
1495                 $object = self::fetchCachedActivity($url, 0);
1496                 if (empty($object)) {
1497                         return '';
1498                 }
1499
1500                 $signer = [];
1501
1502                 if (!empty($object['attributedTo'])) {
1503                         $attributed_to = $object['attributedTo'];
1504                         if (is_array($attributed_to)) {
1505                                 $compacted = JsonLD::compact($object);
1506                                 $attributed_to = JsonLD::fetchElement($compacted, 'as:attributedTo', '@id');
1507                         }
1508                         $signer[] = $attributed_to;
1509                 }
1510
1511                 if (!empty($object['actor'])) {
1512                         $object_actor = $object['actor'];
1513                 } elseif (!empty($attributed_to)) {
1514                         $object_actor = $attributed_to;
1515                 } else {
1516                         // Shouldn't happen
1517                         $object_actor = '';
1518                 }
1519
1520                 $signer[] = $object_actor;
1521
1522                 if (!empty($child['author'])) {
1523                         $actor = $child['author'];
1524                         $signer[] = $actor;
1525                 } else {
1526                         $actor = $object_actor;
1527                 }
1528
1529                 if (!empty($object['published'])) {
1530                         $published = $object['published'];
1531                 } elseif (!empty($child['published'])) {
1532                         $published = $child['published'];
1533                 } else {
1534                         $published = DateTimeFormat::utcNow();
1535                 }
1536
1537                 $activity = [];
1538                 $activity['@context'] = $object['@context'] ?? ActivityPub::CONTEXT;
1539                 unset($object['@context']);
1540                 $activity['id'] = $object['id'];
1541                 $activity['to'] = $object['to'] ?? [];
1542                 $activity['cc'] = $object['cc'] ?? [];
1543                 $activity['actor'] = $actor;
1544                 $activity['object'] = $object;
1545                 $activity['published'] = $published;
1546                 $activity['type'] = 'Create';
1547
1548                 $ldactivity = JsonLD::compact($activity);
1549
1550                 $ldactivity['recursion-depth'] = !empty($child['recursion-depth']) ? $child['recursion-depth'] + 1 : 0;
1551
1552                 if (!empty($relay_actor)) {
1553                         $ldactivity['thread-completion'] = $ldactivity['from-relay'] = Contact::getIdForURL($relay_actor);
1554                         $ldactivity['completion-mode']   = Receiver::COMPLETION_RELAY;
1555                 } elseif (!empty($child['thread-completion'])) {
1556                         $ldactivity['thread-completion'] = $child['thread-completion'];
1557                         $ldactivity['completion-mode']   = $child['completion-mode'] ?? Receiver::COMPLETION_NONE;
1558                 } else {
1559                         $ldactivity['thread-completion'] = Contact::getIdForURL($actor);
1560                         $ldactivity['completion-mode']   = $completion;
1561                 }
1562
1563                 if (!empty($child['thread-children-type'])) {
1564                         $ldactivity['thread-children-type'] = $child['thread-children-type'];
1565                 } elseif (!empty($child['type'])) {
1566                         $ldactivity['thread-children-type'] = $child['type'];
1567                 } else {
1568                         $ldactivity['thread-children-type'] = 'as:Create';
1569                 }
1570
1571                 if (!empty($relay_actor) && !self::acceptIncomingMessage($ldactivity, $object['id'])) {
1572                         return '';
1573                 }
1574
1575                 if (($completion == Receiver::COMPLETION_RELAY) && Queue::exists($url, 'as:Create')) {
1576                         Logger::notice('Activity has already been queued.', ['url' => $url, 'object' => $activity['id']]);
1577                 } elseif (ActivityPub\Receiver::processActivity($ldactivity, json_encode($activity), 0, true, false, $signer, '', $completion)) {
1578                         Logger::notice('Activity had been fetched and processed.', ['url' => $url, 'entry' => $child['entry-id'] ?? 0, 'completion' => $completion, 'object' => $activity['id']]);
1579                 } else {
1580                         Logger::notice('Activity had been fetched and will be processed later.', ['url' => $url, 'entry' => $child['entry-id'] ?? 0, 'completion' => $completion, 'object' => $activity['id']]);
1581                 }
1582
1583                 return $activity['id'];
1584         }
1585
1586         /**
1587          * Test if incoming relay messages should be accepted
1588          *
1589          * @param array $activity activity array
1590          * @param string $id      object ID
1591          * @return boolean true if message is accepted
1592          */
1593         private static function acceptIncomingMessage(array $activity, string $id): bool
1594         {
1595                 if (empty($activity['as:object'])) {
1596                         Logger::info('No object field in activity - accepted', ['id' => $id]);
1597                         return true;
1598                 }
1599
1600                 $replyto = JsonLD::fetchElement($activity['as:object'], 'as:inReplyTo', '@id');
1601                 $uriid = ItemURI::getIdByURI($replyto ?? '');
1602                 if (Post::exists(['uri-id' => $uriid])) {
1603                         Logger::info('Post is a reply to an existing post - accepted', ['id' => $id, 'uri-id' => $uriid, 'replyto' => $replyto]);
1604                         return true;
1605                 }
1606
1607                 $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
1608                 $authorid = Contact::getIdForURL($attributed_to);
1609
1610                 $body = HTML::toBBCode(JsonLD::fetchElement($activity['as:object'], 'as:content', '@value') ?? '');
1611
1612                 $messageTags = [];
1613                 $tags = Receiver::processTags(JsonLD::fetchElementArray($activity['as:object'], 'as:tag') ?? []);
1614                 if (!empty($tags)) {
1615                         foreach ($tags as $tag) {
1616                                 if ($tag['type'] != 'Hashtag') {
1617                                         continue;
1618                                 }
1619                                 $messageTags[] = ltrim(mb_strtolower($tag['name']), '#');
1620                         }
1621                 }
1622
1623                 return Relay::isSolicitedPost($messageTags, $body, $authorid, $id, Protocol::ACTIVITYPUB);
1624         }
1625
1626         /**
1627          * perform a "follow" request
1628          *
1629          * @param array $activity
1630          * @return void
1631          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1632          * @throws \ImagickException
1633          */
1634         public static function followUser(array $activity)
1635         {
1636                 $uid = User::getIdForURL($activity['object_id']);
1637                 if (empty($uid)) {
1638                         Queue::remove($activity);
1639                         return;
1640                 }
1641
1642                 $owner = User::getOwnerDataById($uid);
1643                 if (empty($owner)) {
1644                         return;
1645                 }
1646
1647                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1648                 if (!empty($cid)) {
1649                         self::switchContact($cid);
1650                         Contact::update(['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
1651                 }
1652
1653                 $item = [
1654                         'author-id' => Contact::getIdForURL($activity['actor']),
1655                         'author-link' => $activity['actor'],
1656                 ];
1657
1658                 // Ensure that the contact has got the right network type
1659                 self::switchContact($item['author-id']);
1660
1661                 $result = Contact::addRelationship($owner, [], $item, false, $activity['content'] ?? '');
1662                 if ($result === true) {
1663                         ActivityPub\Transmitter::sendContactAccept($item['author-link'], $activity['id'], $owner['uid']);
1664                 }
1665
1666                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1667                 if (empty($cid)) {
1668                         return;
1669                 }
1670
1671                 if ($result && DI::config()->get('system', 'transmit_pending_events') && ($owner['contact-type'] == Contact::TYPE_COMMUNITY)) {
1672                         self::transmitPendingEvents($cid, $owner['uid']);
1673                 }
1674
1675                 if (empty($contact)) {
1676                         Contact::update(['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
1677                 }
1678                 Logger::notice('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
1679                 Queue::remove($activity);
1680         }
1681
1682         /**
1683          * Transmit pending events to the new follower
1684          *
1685          * @param integer $cid Contact id
1686          * @param integer $uid User id
1687          * @return void
1688          */
1689         private static function transmitPendingEvents(int $cid, int $uid)
1690         {
1691                 $account = DBA::selectFirst('account-user-view', ['ap-inbox', 'ap-sharedinbox'], ['id' => $cid]);
1692                 $inbox = $account['ap-sharedinbox'] ?: $account['ap-inbox'];
1693
1694                 $events = DBA::select('event', ['id'], ["`uid` = ? AND `start` > ? AND `type` != ?", $uid, DateTimeFormat::utcNow(), 'birthday']);
1695                 while ($event = DBA::fetch($events)) {
1696                         $post = Post::selectFirst(['id', 'uri-id', 'created'], ['event-id' => $event['id']]);
1697                         if (empty($post)) {
1698                                 continue;
1699                         }
1700                         if (DI::config()->get('system', 'bulk_delivery')) {
1701                                 Post\Delivery::add($post['uri-id'], $uid, $inbox, $post['created'], Delivery::POST, [$cid]);
1702                                 Worker::add(PRIORITY_HIGH, 'APDelivery', '', 0, $inbox, 0);
1703                         } else {
1704                                 Worker::add(PRIORITY_HIGH, 'APDelivery', Delivery::POST, $post['id'], $inbox, $uid, [$cid], $post['uri-id']);
1705                         }
1706                 }
1707         }
1708
1709         /**
1710          * Update the given profile
1711          *
1712          * @param array $activity
1713          * @throws \Exception
1714          */
1715         public static function updatePerson(array $activity)
1716         {
1717                 if (empty($activity['object_id'])) {
1718                         return;
1719                 }
1720
1721                 Logger::info('Updating profile', ['object' => $activity['object_id']]);
1722                 Contact::updateFromProbeByURL($activity['object_id']);
1723                 Queue::remove($activity);
1724         }
1725
1726         /**
1727          * Delete the given profile
1728          *
1729          * @param array $activity
1730          * @return void
1731          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1732          */
1733         public static function deletePerson(array $activity)
1734         {
1735                 if (empty($activity['object_id']) || empty($activity['actor'])) {
1736                         Logger::info('Empty object id or actor.');
1737                         return;
1738                 }
1739
1740                 if ($activity['object_id'] != $activity['actor']) {
1741                         Logger::info('Object id does not match actor.');
1742                         return;
1743                 }
1744
1745                 $contacts = DBA::select('contact', ['id'], ['nurl' => Strings::normaliseLink($activity['object_id'])]);
1746                 while ($contact = DBA::fetch($contacts)) {
1747                         Contact::remove($contact['id']);
1748                 }
1749                 DBA::close($contacts);
1750
1751                 Logger::info('Deleted contact', ['object' => $activity['object_id']]);
1752                 Queue::remove($activity);
1753         }
1754
1755         /**
1756          * Blocks the user by the contact
1757          *
1758          * @param array $activity
1759          * @return void
1760          * @throws \Exception
1761          */
1762         public static function blockAccount(array $activity)
1763         {
1764                 $cid = Contact::getIdForURL($activity['actor']);
1765                 if (empty($cid)) {
1766                         return;
1767                 }
1768
1769                 $uid = User::getIdForURL($activity['object_id']);
1770                 if (empty($uid)) {
1771                         return;
1772                 }
1773
1774                 Contact\User::setIsBlocked($cid, $uid, true);
1775
1776                 Logger::info('Contact blocked user', ['contact' => $cid, 'user' => $uid]);
1777                 Queue::remove($activity);
1778         }
1779
1780         /**
1781          * Unblocks the user by the contact
1782          *
1783          * @param array $activity
1784          * @return void
1785          * @throws \Exception
1786          */
1787         public static function unblockAccount(array $activity)
1788         {
1789                 $cid = Contact::getIdForURL($activity['actor']);
1790                 if (empty($cid)) {
1791                         return;
1792                 }
1793
1794                 $uid = User::getIdForURL($activity['object_object']);
1795                 if (empty($uid)) {
1796                         return;
1797                 }
1798
1799                 Contact\User::setIsBlocked($cid, $uid, false);
1800
1801                 Logger::info('Contact unblocked user', ['contact' => $cid, 'user' => $uid]);
1802                 Queue::remove($activity);
1803         }
1804
1805         /**
1806          * Accept a follow request
1807          *
1808          * @param array $activity
1809          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1810          * @throws \ImagickException
1811          */
1812         public static function acceptFollowUser(array $activity)
1813         {
1814                 $uid = User::getIdForURL($activity['object_actor']);
1815                 if (empty($uid)) {
1816                         return;
1817                 }
1818
1819                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1820                 if (empty($cid)) {
1821                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1822                         return;
1823                 }
1824
1825                 self::switchContact($cid);
1826
1827                 $fields = ['pending' => false];
1828
1829                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
1830                 if ($contact['rel'] == Contact::FOLLOWER) {
1831                         $fields['rel'] = Contact::FRIEND;
1832                 }
1833
1834                 $condition = ['id' => $cid];
1835                 Contact::update($fields, $condition);
1836                 Logger::info('Accept contact request', ['contact' => $cid, 'user' => $uid]);
1837                 Queue::remove($activity);
1838         }
1839
1840         /**
1841          * Reject a follow request
1842          *
1843          * @param array $activity
1844          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1845          * @throws \ImagickException
1846          */
1847         public static function rejectFollowUser(array $activity)
1848         {
1849                 $uid = User::getIdForURL($activity['object_actor']);
1850                 if (empty($uid)) {
1851                         return;
1852                 }
1853
1854                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1855                 if (empty($cid)) {
1856                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1857                         return;
1858                 }
1859
1860                 self::switchContact($cid);
1861
1862                 $contact = Contact::getById($cid, ['rel']);
1863                 if ($contact['rel'] == Contact::SHARING) {
1864                         Contact::remove($cid);
1865                         Logger::info('Rejected contact request - contact removed', ['contact' => $cid, 'user' => $uid]);
1866                 } elseif ($contact['rel'] == Contact::FRIEND) {
1867                         Contact::update(['rel' => Contact::FOLLOWER], ['id' => $cid]);
1868                 } else {
1869                         Logger::info('Rejected contact request', ['contact' => $cid, 'user' => $uid]);
1870                 }
1871                 Queue::remove($activity);
1872         }
1873
1874         /**
1875          * Undo activity like "like" or "dislike"
1876          *
1877          * @param array $activity
1878          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1879          * @throws \ImagickException
1880          */
1881         public static function undoActivity(array $activity)
1882         {
1883                 if (empty($activity['object_id'])) {
1884                         return;
1885                 }
1886
1887                 if (empty($activity['object_actor'])) {
1888                         return;
1889                 }
1890
1891                 $author_id = Contact::getIdForURL($activity['object_actor']);
1892                 if (empty($author_id)) {
1893                         return;
1894                 }
1895
1896                 Item::markForDeletion(['uri' => $activity['object_id'], 'author-id' => $author_id, 'gravity' => GRAVITY_ACTIVITY]);
1897                 Queue::remove($activity);
1898         }
1899
1900         /**
1901          * Activity to remove a follower
1902          *
1903          * @param array $activity
1904          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1905          * @throws \ImagickException
1906          */
1907         public static function undoFollowUser(array $activity)
1908         {
1909                 $uid = User::getIdForURL($activity['object_object']);
1910                 if (empty($uid)) {
1911                         return;
1912                 }
1913
1914                 $owner = User::getOwnerDataById($uid);
1915                 if (empty($owner)) {
1916                         return;
1917                 }
1918
1919                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1920                 if (empty($cid)) {
1921                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1922                         return;
1923                 }
1924
1925                 self::switchContact($cid);
1926
1927                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1928                 if (!DBA::isResult($contact)) {
1929                         return;
1930                 }
1931
1932                 Contact::removeFollower($contact);
1933                 Logger::info('Undo following request', ['contact' => $cid, 'user' => $uid]);
1934                 Queue::remove($activity);
1935         }
1936
1937         /**
1938          * Switches a contact to AP if needed
1939          *
1940          * @param integer $cid Contact ID
1941          * @return void
1942          * @throws \Exception
1943          */
1944         private static function switchContact(int $cid)
1945         {
1946                 $contact = DBA::selectFirst('contact', ['network', 'url'], ['id' => $cid]);
1947                 if (!DBA::isResult($contact) || in_array($contact['network'], [Protocol::ACTIVITYPUB, Protocol::DFRN]) || Contact::isLocal($contact['url'])) {
1948                         return;
1949                 }
1950
1951                 Logger::info('Change existing contact', ['cid' => $cid, 'previous' => $contact['network']]);
1952                 Contact::updateFromProbe($cid);
1953         }
1954
1955         /**
1956          * Collects implicit mentions like:
1957          * - the author of the parent item
1958          * - all the mentioned conversants in the parent item
1959          *
1960          * @param array $parent Item array with at least ['id', 'author-link', 'alias']
1961          * @return array
1962          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1963          */
1964         private static function getImplicitMentionList(array $parent): array
1965         {
1966                 $parent_terms = Tag::getByURIId($parent['uri-id'], [Tag::MENTION, Tag::IMPLICIT_MENTION, Tag::EXCLUSIVE_MENTION]);
1967
1968                 $parent_author = Contact::getByURL($parent['author-link'], false, ['url', 'nurl', 'alias']);
1969
1970                 $implicit_mentions = [];
1971                 if (empty($parent_author['url'])) {
1972                         Logger::notice('Author public contact unknown.', ['author-link' => $parent['author-link'], 'parent-id' => $parent['id']]);
1973                 } else {
1974                         $implicit_mentions[] = $parent_author['url'];
1975                         $implicit_mentions[] = $parent_author['nurl'];
1976                         $implicit_mentions[] = $parent_author['alias'];
1977                 }
1978
1979                 if (!empty($parent['alias'])) {
1980                         $implicit_mentions[] = $parent['alias'];
1981                 }
1982
1983                 foreach ($parent_terms as $term) {
1984                         $contact = Contact::getByURL($term['url'], false, ['url', 'nurl', 'alias']);
1985                         if (!empty($contact['url'])) {
1986                                 $implicit_mentions[] = $contact['url'];
1987                                 $implicit_mentions[] = $contact['nurl'];
1988                                 $implicit_mentions[] = $contact['alias'];
1989                         }
1990                 }
1991
1992                 return $implicit_mentions;
1993         }
1994
1995         /**
1996          * Strips from the body prepended implicit mentions
1997          *
1998          * @param string $body
1999          * @param array $parent
2000          * @return string
2001          */
2002         private static function removeImplicitMentionsFromBody(string $body, array $parent): string
2003         {
2004                 if (DI::config()->get('system', 'disable_implicit_mentions')) {
2005                         return $body;
2006                 }
2007
2008                 $potential_mentions = self::getImplicitMentionList($parent);
2009
2010                 $kept_mentions = [];
2011
2012                 // Extract one prepended mention at a time from the body
2013                 while(preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $body, $matches)) {
2014                         if (!in_array($matches[2], $potential_mentions)) {
2015                                 $kept_mentions[] = $matches[1];
2016                         }
2017
2018                         $body = $matches[3];
2019                 }
2020
2021                 // Re-appending the kept mentions to the body after extraction
2022                 $kept_mentions[] = $body;
2023
2024                 return implode('', $kept_mentions);
2025         }
2026
2027         /**
2028          * Adds links to string mentions
2029          *
2030          * @param string $body
2031          * @param array  $tags
2032          * @return string
2033          */
2034         protected static function addMentionLinks(string $body, array $tags): string
2035         {
2036                 // This prevents links to be added again to Pleroma-style mention links
2037                 $body = self::normalizeMentionLinks($body);
2038
2039                 $body = BBCode::performWithEscapedTags($body, ['url'], function ($body) use ($tags) {
2040                         foreach ($tags as $tag) {
2041                                 if (empty($tag['name']) || empty($tag['type']) || empty($tag['href']) || !in_array($tag['type'], ['Mention', 'Hashtag'])) {
2042                                         continue;
2043                                 }
2044
2045                                 $hash = substr($tag['name'], 0, 1);
2046                                 $name = substr($tag['name'], 1);
2047                                 if (!in_array($hash, Tag::TAG_CHARACTER)) {
2048                                         $hash = '';
2049                                         $name = $tag['name'];
2050                                 }
2051
2052                                 if (Network::isValidHttpUrl($tag['href'])) {
2053                                         $body = str_replace($tag['name'], $hash . '[url=' . $tag['href'] . ']' . $name . '[/url]', $body);
2054                                 }
2055                         }
2056
2057                         return $body;
2058                 });
2059
2060                 return $body;
2061         }
2062 }