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\Logger;
  28 use Friendica\Core\Protocol;
  29 use Friendica\Core\System;
  30 use Friendica\Database\DBA;
  31 use Friendica\DI;
  32 use Friendica\Model\APContact;
  33 use Friendica\Model\Contact;
  34 use Friendica\Model\Conversation;
  35 use Friendica\Model\Event;
  36 use Friendica\Model\GServer;
  37 use Friendica\Model\Item;
  38 use Friendica\Model\ItemURI;
  39 use Friendica\Model\Mail;
  40 use Friendica\Model\Tag;
  41 use Friendica\Model\User;
  42 use Friendica\Model\Post;
  43 use Friendica\Protocol\Activity;
  44 use Friendica\Protocol\ActivityPub;
  45 use Friendica\Protocol\Relay;
  46 use Friendica\Util\DateTimeFormat;
  47 use Friendica\Util\JsonLD;
  48 use Friendica\Util\Strings;
  49
  50 /**
  51  * ActivityPub Processor Protocol class
  52  */
  53 class Processor
  54 {
  55         /**
  56          * Extracts the tag character (#, @, !) from mention links
  57          *
  58          * @param string $body
  59          * @return string
  60          */
  61         protected static function normalizeMentionLinks(string $body): string
  62         {
  63                 return preg_replace('%\[url=([^\[\]]*)]([#@!])(.*?)\[/url]%ism', '$2[url=$1]$3[/url]', $body);
  64         }
  65
  66         /**
  67          * Convert the language array into a language JSON
  68          *
  69          * @param array $languages
  70          * @return string language JSON
  71          */
  72         private static function processLanguages(array $languages)
  73         {
  74                 $codes = array_keys($languages);
  75                 $lang = [];
  76                 foreach ($codes as $code) {
  77                         $lang[$code] = 1;
  78                 }
  79
  80                 if (empty($lang)) {
  81                         return '';
  82                 }
  83
  84                 return json_encode($lang);
  85         }
  86         /**
  87          * Replaces emojis in the body
  88          *
  89          * @param array $emojis
  90          * @param string $body
  91          *
  92          * @return string with replaced emojis
  93          */
  94         private static function replaceEmojis(int $uri_id, $body, array $emojis)
  95         {
  96                 $body = strtr($body,
  97                         array_combine(
  98                                 array_column($emojis, 'name'),
  99                                 array_map(function ($emoji) {
 100                                         return '[emoji=' . $emoji['href'] . ']' . $emoji['name'] . '[/emoji]';
 101                                 }, $emojis)
 102                         )
 103                 );
 104
 105                 // We store the emoji here to be able to avoid storing it in the media
 106                 foreach ($emojis as $emoji) {
 107                         Post\Link::getByLink($uri_id, $emoji['href']);
 108                 }
 109                 return $body;
 110         }
 111
 112         /**
 113          * Store attached media files in the post-media table
 114          *
 115          * @param int $uriid
 116          * @param array $attachment
 117          * @return void
 118          */
 119         private static function storeAttachmentAsMedia(int $uriid, array $attachment)
 120         {
 121                 if (empty($attachment['url'])) {
 122                         return;
 123                 }
 124
 125                 $data = ['uri-id' => $uriid];
 126                 $data['type'] = Post\Media::UNKNOWN;
 127                 $data['url'] = $attachment['url'];
 128                 $data['mimetype'] = $attachment['mediaType'] ?? null;
 129                 $data['height'] = $attachment['height'] ?? null;
 130                 $data['width'] = $attachment['width'] ?? null;
 131                 $data['size'] = $attachment['size'] ?? null;
 132                 $data['preview'] = $attachment['image'] ?? null;
 133                 $data['description'] = $attachment['name'] ?? null;
 134
 135                 Post\Media::insert($data);
 136         }
 137
 138         /**
 139          * Stire attachment data
 140          *
 141          * @param array   $activity
 142          * @param array   $item
 143          */
 144         private static function storeAttachments($activity, $item)
 145         {
 146                 if (empty($activity['attachments'])) {
 147                         return;
 148                 }
 149
 150                 foreach ($activity['attachments'] as $attach) {
 151                         self::storeAttachmentAsMedia($item['uri-id'], $attach);
 152                 }
 153         }
 154
 155         /**
 156          * Store attachment data
 157          *
 158          * @param array   $activity
 159          * @param array   $item
 160          */
 161         private static function storeQuestion($activity, $item)
 162         {
 163                 if (empty($activity['question'])) {
 164                         return;
 165                 }
 166                 $question = ['multiple' => $activity['question']['multiple']];
 167
 168                 if (!empty($activity['question']['voters'])) {
 169                         $question['voters'] = $activity['question']['voters'];
 170                 }
 171
 172                 if (!empty($activity['question']['end-time'])) {
 173                         $question['end-time'] = $activity['question']['end-time'];
 174                 }
 175
 176                 Post\Question::update($item['uri-id'], $question);
 177
 178                 foreach ($activity['question']['options'] as $key => $option) {
 179                         $option = ['name' => $option['name'], 'replies' => $option['replies']];
 180                         Post\QuestionOption::update($item['uri-id'], $key, $option);
 181                 }
 182
 183                 Logger::debug('Storing incoming question', ['type' => $activity['type'], 'uri-id' => $item['uri-id'], 'question' => $activity['question']]);
 184         }
 185
 186         /**
 187          * Updates a message
 188          *
 189          * @param array $activity Activity array
 190          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 191          */
 192         public static function updateItem($activity)
 193         {
 194                 $item = Post::selectFirst(['uri', 'uri-id', 'thr-parent', 'gravity', 'post-type'], ['uri' => $activity['id']]);
 195                 if (!DBA::isResult($item)) {
 196                         Logger::warning('No existing item, item will be created', ['uri' => $activity['id']]);
 197                         $item = self::createItem($activity);
 198                         if (empty($item)) {
 199                                 return;
 200                         }
 201
 202                         self::postItem($activity, $item);
 203                         return;
 204                 }
 205
 206                 $item['changed'] = DateTimeFormat::utcNow();
 207                 $item['edited'] = DateTimeFormat::utc($activity['updated']);
 208
 209                 $item = self::processContent($activity, $item);
 210
 211                 self::storeAttachments($activity, $item);
 212                 self::storeQuestion($activity, $item);
 213
 214                 if (empty($item)) {
 215                         return;
 216                 }
 217
 218                 Item::update($item, ['uri' => $activity['id']]);
 219
 220                 if ($activity['object_type'] == 'as:Event') {
 221                         $posts = Post::select(['event-id', 'uid'], ["`uri` = ? AND `event-id` > ?", $activity['id'], 0]);
 222                         while ($post = DBA::fetch($posts)) {
 223                                 self::updateEvent($post['event-id'], $activity);
 224                         }
 225                 }
 226         }
 227
 228         /**
 229          * Update an existing event
 230          *
 231          * @param int $event_id
 232          * @param array $activity
 233          */
 234         private static function updateEvent(int $event_id, array $activity)
 235         {
 236                 $event = DBA::selectFirst('event', [], ['id' => $event_id]);
 237
 238                 $event['edited']   = DateTimeFormat::utc($activity['updated']);
 239                 $event['summary']  = HTML::toBBCode($activity['name']);
 240                 $event['desc']     = HTML::toBBCode($activity['content']);
 241                 $event['start']    = $activity['start-time'];
 242                 $event['finish']   = $activity['end-time'];
 243                 $event['nofinish'] = empty($event['finish']);
 244                 $event['location'] = $activity['location'];
 245
 246                 Logger::info('Updating event', ['uri' => $activity['id'], 'id' => $event_id]);
 247                 Event::store($event);
 248         }
 249
 250         /**
 251          * Prepares data for a message
 252          *
 253          * @param array $activity Activity array
 254          * @return array Internal item
 255          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 256          * @throws \ImagickException
 257          */
 258         public static function createItem($activity)
 259         {
 260                 $item = [];
 261                 $item['verb'] = Activity::POST;
 262                 $item['thr-parent'] = $activity['reply-to-id'];
 263
 264                 if ($activity['reply-to-id'] == $activity['id']) {
 265                         $item['gravity'] = GRAVITY_PARENT;
 266                         $item['object-type'] = Activity\ObjectType::NOTE;
 267                 } else {
 268                         $item['gravity'] = GRAVITY_COMMENT;
 269                         $item['object-type'] = Activity\ObjectType::COMMENT;
 270                 }
 271
 272                 if (empty($activity['directmessage']) && ($activity['id'] != $activity['reply-to-id']) && !Post::exists(['uri' => $activity['reply-to-id']])) {
 273                         Logger::notice('Parent not found. Try to refetch it.', ['parent' => $activity['reply-to-id']]);
 274                         self::fetchMissingActivity($activity['reply-to-id'], $activity, '', Receiver::COMPLETION_AUTO);
 275                 }
 276
 277                 $item['diaspora_signed_text'] = $activity['diaspora:comment'] ?? '';
 278
 279                 /// @todo What to do with $activity['context']?
 280                 if (empty($activity['directmessage']) && ($item['gravity'] != GRAVITY_PARENT) && !Post::exists(['uri' => $item['thr-parent']])) {
 281                         Logger::info('Parent not found, message will be discarded.', ['thr-parent' => $item['thr-parent']]);
 282                         return [];
 283                 }
 284
 285                 $item['network'] = Protocol::ACTIVITYPUB;
 286                 $item['author-link'] = $activity['author'];
 287                 $item['author-id'] = Contact::getIdForURL($activity['author']);
 288                 $item['owner-link'] = $activity['actor'];
 289                 $item['owner-id'] = Contact::getIdForURL($activity['actor']);
 290
 291                 if (in_array(0, $activity['receiver']) && !empty($activity['unlisted'])) {
 292                         $item['private'] = Item::UNLISTED;
 293                 } elseif (in_array(0, $activity['receiver'])) {
 294                         $item['private'] = Item::PUBLIC;
 295                 } else {
 296                         $item['private'] = Item::PRIVATE;
 297                 }
 298
 299                 if (!empty($activity['raw'])) {
 300                         $item['source'] = $activity['raw'];
 301                         $item['protocol'] = Conversation::PARCEL_ACTIVITYPUB;
 302                         $item['conversation-href'] = $activity['context'] ?? '';
 303                         $item['conversation-uri'] = $activity['conversation'] ?? '';
 304
 305                         if (isset($activity['push'])) {
 306                                 $item['direction'] = $activity['push'] ? Conversation::PUSH : Conversation::PULL;
 307                         }
 308                 }
 309
 310                 if (!empty($activity['from-relay'])) {
 311                         $item['direction'] = Conversation::RELAY;
 312                 }
 313
 314                 if ($activity['object_type'] == 'as:Article') {
 315                         $item['post-type'] = Item::PT_ARTICLE;
 316                 } elseif ($activity['object_type'] == 'as:Audio') {
 317                         $item['post-type'] = Item::PT_AUDIO;
 318                 } elseif ($activity['object_type'] == 'as:Document') {
 319                         $item['post-type'] = Item::PT_DOCUMENT;
 320                 } elseif ($activity['object_type'] == 'as:Event') {
 321                         $item['post-type'] = Item::PT_EVENT;
 322                 } elseif ($activity['object_type'] == 'as:Image') {
 323                         $item['post-type'] = Item::PT_IMAGE;
 324                 } elseif ($activity['object_type'] == 'as:Page') {
 325                         $item['post-type'] = Item::PT_PAGE;
 326                 } elseif ($activity['object_type'] == 'as:Question') {
 327                         $item['post-type'] = Item::PT_POLL;
 328                 } elseif ($activity['object_type'] == 'as:Video') {
 329                         $item['post-type'] = Item::PT_VIDEO;
 330                 } else {
 331                         $item['post-type'] = Item::PT_NOTE;
 332                 }
 333
 334                 $item['isForum'] = false;
 335
 336                 if (!empty($activity['thread-completion'])) {
 337                         if ($activity['thread-completion'] != $item['owner-id']) {
 338                                 $actor = Contact::getById($activity['thread-completion'], ['url']);
 339                                 $item['causer-link'] = $actor['url'];
 340                                 $item['causer-id'] = $activity['thread-completion'];
 341                                 Logger::info('Use inherited actor as causer.', ['id' => $item['owner-id'], 'activity' => $activity['thread-completion'], 'owner' => $item['owner-link'], 'actor' => $actor['url']]);
 342                         } else {
 343                                 // Store the original actor in the "causer" fields to enable the check for ignored or blocked contacts
 344                                 $item['causer-link'] = $item['owner-link'];
 345                                 $item['causer-id']   = $item['owner-id'];
 346                                 Logger::info('Use actor as causer.', ['id' => $item['owner-id'], 'actor' => $item['owner-link']]);
 347                         }
 348
 349                         $item['owner-link'] = $item['author-link'];
 350                         $item['owner-id'] = $item['author-id'];
 351                 } else {
 352                         $actor = APContact::getByURL($item['owner-link'], false);
 353                         $item['isForum'] = ($actor['type'] == 'Group');
 354                 }
 355
 356                 $item['uri'] = $activity['id'];
 357
 358                 if (empty($activity['published']) || empty($activity['updated'])) {
 359                         DI::logger()->notice('published or updated keys are empty for activity', ['activity' => $activity, 'callstack' => System::callstack(10)]);
 360                 }
 361
 362                 $item['created'] = DateTimeFormat::utc($activity['published'] ?? 'now');
 363                 $item['edited'] = DateTimeFormat::utc($activity['updated'] ?? 'now');
 364                 $guid = $activity['sc:identifier'] ?: self::getGUIDByURL($item['uri']);
 365                 $item['guid'] = $activity['diaspora:guid'] ?: $guid;
 366
 367                 $item['uri-id'] = ItemURI::insert(['uri' => $item['uri'], 'guid' => $item['guid']]);
 368                 if (empty($item['uri-id'])) {
 369                         Logger::warning('Unable to get a uri-id for an item uri', ['uri' => $item['uri'], 'guid' => $item['guid']]);
 370                         return [];
 371                 }
 372
 373                 $item = self::processContent($activity, $item);
 374                 if (empty($item)) {
 375                         Logger::info('Message was not processed');
 376                         return [];
 377                 }
 378
 379                 $item['plink'] = $activity['alternate-url'] ?? $item['uri'];
 380
 381                 self::storeAttachments($activity, $item);
 382                 self::storeQuestion($activity, $item);
 383
 384                 // We received the post via AP, so we set the protocol of the server to AP
 385                 $contact = Contact::getById($item['author-id'], ['gsid']);
 386                 if (!empty($contact['gsid'])) {
 387                         GServer::setProtocol($contact['gsid'], Post\DeliveryData::ACTIVITYPUB);
 388                 }
 389
 390                 if ($item['author-id'] != $item['owner-id']) {
 391                         $contact = Contact::getById($item['owner-id'], ['gsid']);
 392                         if (!empty($contact['gsid'])) {
 393                                 GServer::setProtocol($contact['gsid'], Post\DeliveryData::ACTIVITYPUB);
 394                         }
 395                 }
 396
 397                 return $item;
 398         }
 399
 400         /**
 401          * Delete items
 402          *
 403          * @param array $activity
 404          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 405          * @throws \ImagickException
 406          */
 407         public static function deleteItem($activity)
 408         {
 409                 $owner = Contact::getIdForURL($activity['actor']);
 410
 411                 Logger::info('Deleting item', ['object' => $activity['object_id'], 'owner'  => $owner]);
 412                 Item::markForDeletion(['uri' => $activity['object_id'], 'owner-id' => $owner]);
 413         }
 414
 415         /**
 416          * Prepare the item array for an activity
 417          *
 418          * @param array $activity Activity array
 419          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 420          * @throws \ImagickException
 421          */
 422         public static function addTag($activity)
 423         {
 424                 if (empty($activity['object_content']) || empty($activity['object_id'])) {
 425                         return;
 426                 }
 427
 428                 foreach ($activity['receiver'] as $receiver) {
 429                         $item = Post::selectFirst(['id', 'uri-id', 'origin', 'author-link'], ['uri' => $activity['target_id'], 'uid' => $receiver]);
 430                         if (!DBA::isResult($item)) {
 431                                 // We don't fetch missing content for this purpose
 432                                 continue;
 433                         }
 434
 435                         if (($item['author-link'] != $activity['actor']) && !$item['origin']) {
 436                                 Logger::info('Not origin, not from the author, skipping update', ['id' => $item['id'], 'author' => $item['author-link'], 'actor' => $activity['actor']]);
 437                                 continue;
 438                         }
 439
 440                         Tag::store($item['uri-id'], Tag::HASHTAG, $activity['object_content'], $activity['object_id']);
 441                         Logger::info('Tagged item', ['id' => $item['id'], 'tag' => $activity['object_content'], 'uri' => $activity['target_id'], 'actor' => $activity['actor']]);
 442                 }
 443         }
 444
 445         /**
 446          * Prepare the item array for an activity
 447          *
 448          * @param array  $activity Activity array
 449          * @param string $verb     Activity verb
 450          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 451          * @throws \ImagickException
 452          */
 453         public static function createActivity($activity, $verb)
 454         {
 455                 $item = self::createItem($activity);
 456                 if (empty($item)) {
 457                         return;
 458                 }
 459
 460                 $item['verb'] = $verb;
 461                 $item['thr-parent'] = $activity['object_id'];
 462                 $item['gravity'] = GRAVITY_ACTIVITY;
 463                 unset($item['post-type']);
 464                 $item['object-type'] = Activity\ObjectType::NOTE;
 465
 466                 if (!empty($activity['content'])) {
 467                         $item['body'] = HTML::toBBCode($activity['content']);
 468                 }
 469
 470                 $item['diaspora_signed_text'] = $activity['diaspora:like'] ?? '';
 471
 472                 self::postItem($activity, $item);
 473         }
 474
 475         /**
 476          * Fetch the Uri-Id of a post for the "featured" collection
 477          *
 478          * @param array $activity
 479          * @return null|int
 480          */
 481         private static function getUriIdForFeaturedCollection(array $activity)
 482         {
 483                 $actor = APContact::getByURL($activity['actor']);
 484                 if (empty($actor)) {
 485                         return null;
 486                 }
 487
 488                 // Refetch the account when the "featured" collection is missing.
 489                 // This can be removed in a future version (end of 2022 should be good).
 490                 if (empty($actor['featured'])) {
 491                         $actor = APContact::getByURL($activity['actor'], true);
 492                         if (empty($actor)) {
 493                                 return null;
 494                         }
 495                 }
 496
 497                 if ($activity['target_id'] != $actor['featured']) {
 498                         return null;
 499                 }
 500
 501                 $id = Contact::getIdForURL($activity['actor']);
 502                 if (empty($id)) {
 503                         return null;
 504                 }
 505
 506                 $parent = Post::selectFirst(['uri-id'], ['uri' => $activity['object_id'], 'author-id' => $id]);
 507                 if (!empty($parent['uri-id'])) {
 508                         return $parent['uri-id'];
 509                 }
 510
 511                 return null;
 512         }
 513
 514         /**
 515          * Add a post to the "Featured" collection
 516          *
 517          * @param array $activity
 518          */
 519         public static function addToFeaturedCollection(array $activity)
 520         {
 521                 $uriid = self::getUriIdForFeaturedCollection($activity);
 522                 if (empty($uriid)) {
 523                         return;
 524                 }
 525
 526                 Logger::debug('Add post to featured collection', ['uri-id' => $uriid]);
 527
 528                 Post\Collection::add($uriid, Post\Collection::FEATURED);
 529         }
 530
 531         /**
 532          * Remove a post to the "Featured" collection
 533          *
 534          * @param array $activity
 535          */
 536         public static function removeFromFeaturedCollection(array $activity)
 537         {
 538                 $uriid = self::getUriIdForFeaturedCollection($activity);
 539                 if (empty($uriid)) {
 540                         return;
 541                 }
 542
 543                 Logger::debug('Remove post from featured collection', ['uri-id' => $uriid]);
 544
 545                 Post\Collection::remove($uriid, Post\Collection::FEATURED);
 546         }
 547
 548         /**
 549          * Create an event
 550          *
 551          * @param array $activity Activity array
 552          * @param array $item
 553          *
 554          * @return int event id
 555          * @throws \Exception
 556          */
 557         public static function createEvent($activity, $item)
 558         {
 559                 $event['summary']   = HTML::toBBCode($activity['name'] ?: $activity['summary']);
 560                 $event['desc']      = HTML::toBBCode($activity['content']);
 561                 $event['start']     = $activity['start-time'];
 562                 $event['finish']    = $activity['end-time'];
 563                 $event['nofinish']  = empty($event['finish']);
 564                 $event['location']  = $activity['location'];
 565                 $event['cid']       = $item['contact-id'];
 566                 $event['uid']       = $item['uid'];
 567                 $event['uri']       = $item['uri'];
 568                 $event['edited']    = $item['edited'];
 569                 $event['private']   = $item['private'];
 570                 $event['guid']      = $item['guid'];
 571                 $event['plink']     = $item['plink'];
 572                 $event['network']   = $item['network'];
 573                 $event['protocol']  = $item['protocol'];
 574                 $event['direction'] = $item['direction'];
 575                 $event['source']    = $item['source'];
 576
 577                 $ev = DBA::selectFirst('event', ['id'], ['uri' => $item['uri'], 'uid' => $item['uid']]);
 578                 if (DBA::isResult($ev)) {
 579                         $event['id'] = $ev['id'];
 580                 }
 581
 582                 $event_id = Event::store($event);
 583
 584                 Logger::info('Event was stored', ['id' => $event_id]);
 585
 586                 return $event_id;
 587         }
 588
 589         /**
 590          * Process the content
 591          *
 592          * @param array $activity Activity array
 593          * @param array $item
 594          * @return array|bool Returns the item array or false if there was an unexpected occurrence
 595          * @throws \Exception
 596          */
 597         private static function processContent($activity, $item)
 598         {
 599                 if (!empty($activity['mediatype']) && ($activity['mediatype'] == 'text/markdown')) {
 600                         $item['title'] = Markdown::toBBCode($activity['name']);
 601                         $content = Markdown::toBBCode($activity['content']);
 602                 } elseif (!empty($activity['mediatype']) && ($activity['mediatype'] == 'text/bbcode')) {
 603                         $item['title'] = $activity['name'];
 604                         $content = $activity['content'];
 605                 } else {
 606                         // By default assume "text/html"
 607                         $item['title'] = HTML::toBBCode($activity['name']);
 608                         $content = HTML::toBBCode($activity['content']);
 609                 }
 610
 611                 if (!empty($activity['languages'])) {
 612                         $item['language'] = self::processLanguages($activity['languages']);
 613                 }
 614
 615                 if (!empty($activity['emojis'])) {
 616                         $content = self::replaceEmojis($item['uri-id'], $content, $activity['emojis']);
 617                 }
 618
 619                 $content = self::addMentionLinks($content, $activity['tags']);
 620
 621                 if (!empty($activity['source'])) {
 622                         $item['body'] = $activity['source'];
 623                         $item['raw-body'] = $content;
 624                         $item['body'] = Item::improveSharedDataInBody($item);
 625                 } else {
 626                         if (empty($activity['directmessage']) && ($item['thr-parent'] != $item['uri']) && ($item['gravity'] == GRAVITY_COMMENT)) {
 627                                 $item_private = !in_array(0, $activity['item_receiver']);
 628                                 $parent = Post::selectFirst(['id', 'uri-id', 'private', 'author-link', 'alias'], ['uri' => $item['thr-parent']]);
 629                                 if (!DBA::isResult($parent)) {
 630                                         Logger::warning('Unknown parent item.', ['uri' => $item['thr-parent']]);
 631                                         return false;
 632                                 }
 633                                 if ($item_private && ($parent['private'] != Item::PRIVATE)) {
 634                                         Logger::warning('Item is private but the parent is not. Dropping.', ['item-uri' => $item['uri'], 'thr-parent' => $item['thr-parent']]);
 635                                         return false;
 636                                 }
 637
 638                                 $content = self::removeImplicitMentionsFromBody($content, $parent);
 639                         }
 640                         $item['content-warning'] = HTML::toBBCode($activity['summary']);
 641                         $item['raw-body'] = $item['body'] = $content;
 642                 }
 643
 644                 self::storeFromBody($item);
 645                 self::storeTags($item['uri-id'], $activity['tags']);
 646
 647                 self::storeReceivers($item['uri-id'], $activity['receiver_urls'] ?? []);
 648
 649                 $item['location'] = $activity['location'];
 650
 651                 if (!empty($activity['latitude']) && !empty($activity['longitude'])) {
 652                         $item['coord'] = $activity['latitude'] . ' ' . $activity['longitude'];
 653                 }
 654
 655                 $item['app'] = $activity['generator'];
 656
 657                 return $item;
 658         }
 659
 660         /**
 661          * Store hashtags and mentions
 662          *
 663          * @param array $item
 664          */
 665         private static function storeFromBody(array $item)
 666         {
 667                 // Make sure to delete all existing tags (can happen when called via the update functionality)
 668                 DBA::delete('post-tag', ['uri-id' => $item['uri-id']]);
 669
 670                 Tag::storeFromBody($item['uri-id'], $item['body'], '@!');
 671         }
 672
 673         /**
 674          * Generate a GUID out of an URL of an ActivityPub post.
 675          *
 676          * @param string $url message URL
 677          * @return string with GUID
 678          */
 679         private static function getGUIDByURL(string $url)
 680         {
 681                 $parsed = parse_url($url);
 682
 683                 $host_hash = hash('crc32', $parsed['host']);
 684
 685                 unset($parsed["scheme"]);
 686                 unset($parsed["host"]);
 687
 688                 $path = implode("/", $parsed);
 689
 690                 return $host_hash . '-'. hash('fnv164', $path) . '-'. hash('joaat', $path);
 691         }
 692
 693         /**
 694          * Checks if an incoming message is wanted
 695          *
 696          * @param array $activity
 697          * @param array $item
 698          * @return boolean Is the message wanted?
 699          */
 700         private static function isSolicitedMessage(array $activity, array $item)
 701         {
 702                 // The checks are split to improve the support when searching why a message was accepted.
 703                 if (count($activity['receiver']) != 1) {
 704                         // The message has more than one receiver, so it is wanted.
 705                         Logger::debug('Message has got several receivers - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 706                         return true;
 707                 }
 708
 709                 if ($item['private'] == Item::PRIVATE) {
 710                         // We only look at public posts here. Private posts are expected to be intentionally posted to the single receiver.
 711                         Logger::debug('Message is private - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 712                         return true;
 713                 }
 714
 715                 if (!empty($activity['from-relay'])) {
 716                         // We check relay posts at another place. When it arrived here, the message is already checked.
 717                         Logger::debug('Message is a relay post that is already checked - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 718                         return true;
 719                 }
 720
 721                 if (in_array($activity['completion-mode'] ?? Receiver::COMPLETION_NONE, [Receiver::COMPLETION_MANUAL, Receiver::COMPLETION_ANNOUCE])) {
 722                         // Manual completions and completions caused by reshares are allowed without any further checks.
 723                         Logger::debug('Message is in completion mode - accepted', ['mode' => $activity['completion-mode'], 'uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 724                         return true;
 725                 }
 726
 727                 if ($item['gravity'] != GRAVITY_PARENT) {
 728                         // We cannot reliably check at this point if a comment or activity belongs to an accepted post or needs to be fetched
 729                         // This can possibly be improved in the future.
 730                         Logger::debug('Message is no parent - accepted', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 731                         return true;
 732                 }
 733
 734                 $tags = array_column(Tag::getByURIId($item['uri-id'], [Tag::HASHTAG]), 'name');
 735                 if (Relay::isSolicitedPost($tags, $item['body'], $item['author-id'], $item['uri'], Protocol::ACTIVITYPUB)) {
 736                         Logger::debug('Post is accepted because of the relay settings', ['uri-id' => $item['uri-id'], 'guid' => $item['guid'], 'url' => $item['uri']]);
 737                         return true;
 738                 } else {
 739                         return false;
 740                 }
 741         }
 742
 743         /**
 744          * Creates an item post
 745          *
 746          * @param array $activity Activity data
 747          * @param array $item     item array
 748          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 749          * @throws \ImagickException
 750          */
 751         public static function postItem(array $activity, array $item)
 752         {
 753                 if (empty($item)) {
 754                         return;
 755                 }
 756
 757                 $stored = false;
 758                 ksort($activity['receiver']);
 759
 760                 if (!self::isSolicitedMessage($activity, $item)) {
 761                         DBA::delete('item-uri', ['id' => $item['uri-id']]);
 762                         return;
 763                 }
 764
 765                 foreach ($activity['receiver'] as $receiver) {
 766                         if ($receiver == -1) {
 767                                 continue;
 768                         }
 769
 770                         $item['uid'] = $receiver;
 771
 772                         $type = $activity['reception_type'][$receiver] ?? Receiver::TARGET_UNKNOWN;
 773                         switch($type) {
 774                                 case Receiver::TARGET_TO:
 775                                         $item['post-reason'] = Item::PR_TO;
 776                                         break;
 777                                 case Receiver::TARGET_CC:
 778                                         $item['post-reason'] = Item::PR_CC;
 779                                         break;
 780                                 case Receiver::TARGET_BTO:
 781                                         $item['post-reason'] = Item::PR_BTO;
 782                                         break;
 783                                 case Receiver::TARGET_BCC:
 784                                         $item['post-reason'] = Item::PR_BCC;
 785                                         break;
 786                                 case Receiver::TARGET_FOLLOWER:
 787                                         $item['post-reason'] = Item::PR_FOLLOWER;
 788                                         break;
 789                                 case Receiver::TARGET_ANSWER:
 790                                         $item['post-reason'] = Item::PR_COMMENT;
 791                                         break;
 792                                 case Receiver::TARGET_GLOBAL:
 793                                         $item['post-reason'] = Item::PR_GLOBAL;
 794                                         break;
 795                                 default:
 796                                         $item['post-reason'] = Item::PR_NONE;
 797                         }
 798
 799                         if (!empty($activity['from-relay'])) {
 800                                 $item['post-reason'] = Item::PR_RELAY;
 801                         } elseif (!empty($activity['thread-completion'])) {
 802                                 $item['post-reason'] = Item::PR_FETCHED;
 803                         }
 804
 805                         if ($item['isForum'] ?? false) {
 806                                 $item['contact-id'] = Contact::getIdForURL($activity['actor'], $receiver);
 807                         } else {
 808                                 $item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver);
 809                         }
 810
 811                         if (($receiver != 0) && empty($item['contact-id'])) {
 812                                 $item['contact-id'] = Contact::getIdForURL($activity['author']);
 813                         }
 814
 815                         if (!empty($activity['directmessage'])) {
 816                                 self::postMail($activity, $item);
 817                                 continue;
 818                         }
 819
 820                         if (!($item['isForum'] ?? false) && ($receiver != 0) && ($item['gravity'] == GRAVITY_PARENT) && !Contact::isSharingByURL($activity['author'], $receiver)) {
 821                                 if ($item['post-reason'] == Item::PR_BCC) {
 822                                         Logger::info('Top level post via BCC from a non sharer, ignoring', ['uid' => $receiver, 'contact' => $item['contact-id']]);
 823                                         continue;
 824                                 }
 825
 826                                 if (
 827                                         !empty($activity['thread-children-type'])
 828                                         && in_array($activity['thread-children-type'], Receiver::ACTIVITY_TYPES)
 829                                         && DI::pConfig()->get($receiver, 'system', 'accept_only_sharer') != Item::COMPLETION_LIKE
 830                                 ) {
 831                                         Logger::info('Top level post from thread completion from a non sharer had been initiated via an activity, ignoring',
 832                                                 ['type' => $activity['thread-children-type'], 'user' => $item['uid'], 'causer' => $item['causer-link'], 'author' => $activity['author'], 'url' => $item['uri']]);
 833                                         continue;
 834                                 }
 835                         }
 836
 837                         $is_forum = false;
 838
 839                         if ($receiver != 0) {
 840                                 $user = User::getById($receiver, ['account-type']);
 841                                 if (!empty($user['account-type'])) {
 842                                         $is_forum = ($user['account-type'] == User::ACCOUNT_TYPE_COMMUNITY);
 843                                 }
 844                         }
 845
 846                         if (!$is_forum && DI::pConfig()->get($receiver, 'system', 'accept_only_sharer') == Item::COMPLETION_NONE && ($receiver != 0) && ($item['gravity'] == GRAVITY_PARENT)) {
 847                                 $skip = !Contact::isSharingByURL($activity['author'], $receiver);
 848
 849                                 if ($skip && (($activity['type'] == 'as:Announce') || ($item['isForum'] ?? false))) {
 850                                         $skip = !Contact::isSharingByURL($activity['actor'], $receiver);
 851                                 }
 852
 853                                 if ($skip) {
 854                                         Logger::info('Skipping post', ['uid' => $receiver, 'url' => $item['uri']]);
 855                                         continue;
 856                                 }
 857
 858                                 Logger::info('Accepting post', ['uid' => $receiver, 'url' => $item['uri']]);
 859                         }
 860
 861                         if (($item['gravity'] != GRAVITY_ACTIVITY) && ($activity['object_type'] == 'as:Event')) {
 862                                 $event_id = self::createEvent($activity, $item);
 863
 864                                 $item = Event::getItemArrayForImportedId($event_id, $item);
 865                         }
 866
 867                         $item_id = Item::insert($item);
 868                         if ($item_id) {
 869                                 Logger::info('Item insertion successful', ['user' => $item['uid'], 'item_id' => $item_id]);
 870                         } else {
 871                                 Logger::notice('Item insertion aborted', ['user' => $item['uid']]);
 872                         }
 873
 874                         if ($item['uid'] == 0) {
 875                                 $stored = $item_id;
 876                         }
 877                 }
 878
 879                 // Store send a follow request for every reshare - but only when the item had been stored
 880                 if ($stored && ($item['private'] != Item::PRIVATE) && ($item['gravity'] == GRAVITY_PARENT) && ($item['author-link'] != $item['owner-link'])) {
 881                         $author = APContact::getByURL($item['owner-link'], false);
 882                         // We send automatic follow requests for reshared messages. (We don't need though for forum posts)
 883                         if ($author['type'] != 'Group') {
 884                                 Logger::info('Send follow request', ['uri' => $item['uri'], 'stored' => $stored, 'to' => $item['author-link']]);
 885                                 ActivityPub\Transmitter::sendFollowObject($item['uri'], $item['author-link']);
 886                         }
 887                 }
 888         }
 889
 890         /**
 891          * Store tags and mentions into the tag table
 892          *
 893          * @param integer $uriid
 894          * @param array $tags
 895          */
 896         private static function storeTags(int $uriid, array $tags = null)
 897         {
 898                 foreach ($tags as $tag) {
 899                         if (empty($tag['name']) || empty($tag['type']) || !in_array($tag['type'], ['Mention', 'Hashtag'])) {
 900                                 continue;
 901                         }
 902
 903                         $hash = substr($tag['name'], 0, 1);
 904
 905                         if ($tag['type'] == 'Mention') {
 906                                 if (in_array($hash, [Tag::TAG_CHARACTER[Tag::MENTION],
 907                                         Tag::TAG_CHARACTER[Tag::EXCLUSIVE_MENTION],
 908                                         Tag::TAG_CHARACTER[Tag::IMPLICIT_MENTION]])) {
 909                                         $tag['name'] = substr($tag['name'], 1);
 910                                 }
 911                                 $type = Tag::IMPLICIT_MENTION;
 912
 913                                 if (!empty($tag['href'])) {
 914                                         $apcontact = APContact::getByURL($tag['href']);
 915                                         if (!empty($apcontact['name']) || !empty($apcontact['nick'])) {
 916                                                 $tag['name'] = $apcontact['name'] ?: $apcontact['nick'];
 917                                         }
 918                                 }
 919                         } elseif ($tag['type'] == 'Hashtag') {
 920                                 if ($hash == Tag::TAG_CHARACTER[Tag::HASHTAG]) {
 921                                         $tag['name'] = substr($tag['name'], 1);
 922                                 }
 923                                 $type = Tag::HASHTAG;
 924                         }
 925
 926                         if (empty($tag['name'])) {
 927                                 continue;
 928                         }
 929
 930                         Tag::store($uriid, $type, $tag['name'], $tag['href']);
 931                 }
 932         }
 933
 934         public static function storeReceivers(int $uriid, array $receivers)
 935         {
 936                 foreach (['as:to' => Tag::TO, 'as:cc' => Tag::CC, 'as:bto' => Tag::BTO, 'as:bcc' => Tag::BCC] as $element => $type) {
 937                         if (!empty($receivers[$element])) {
 938                                 foreach ($receivers[$element] as $receiver) {
 939                                         if ($receiver == ActivityPub::PUBLIC_COLLECTION) {
 940                                                 $name = Receiver::PUBLIC_COLLECTION;
 941                                         } else {
 942                                                 $name = trim(parse_url($receiver, PHP_URL_PATH), '/');
 943                                         }
 944                                         Tag::store($uriid, $type, $name, $receiver);
 945                                 }
 946                         }
 947                 }
 948         }
 949
 950         /**
 951          * Creates an mail post
 952          *
 953          * @param array $activity Activity data
 954          * @param array $item     item array
 955          * @return int|bool New mail table row id or false on error
 956          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 957          */
 958         private static function postMail($activity, $item)
 959         {
 960                 if (($item['gravity'] != GRAVITY_PARENT) && !DBA::exists('mail', ['uri' => $item['thr-parent'], 'uid' => $item['uid']])) {
 961                         Logger::info('Parent not found, mail will be discarded.', ['uid' => $item['uid'], 'uri' => $item['thr-parent']]);
 962                         return false;
 963                 }
 964
 965                 Logger::info('Direct Message', $item);
 966
 967                 $msg = [];
 968                 $msg['uid'] = $item['uid'];
 969
 970                 $msg['contact-id'] = $item['contact-id'];
 971
 972                 $contact = Contact::getById($item['contact-id'], ['name', 'url', 'photo']);
 973                 $msg['from-name'] = $contact['name'];
 974                 $msg['from-url'] = $contact['url'];
 975                 $msg['from-photo'] = $contact['photo'];
 976
 977                 $msg['uri'] = $item['uri'];
 978                 $msg['created'] = $item['created'];
 979
 980                 $parent = DBA::selectFirst('mail', ['parent-uri', 'title'], ['uri' => $item['thr-parent']]);
 981                 if (DBA::isResult($parent)) {
 982                         $msg['parent-uri'] = $parent['parent-uri'];
 983                         $msg['title'] = $parent['title'];
 984                 } else {
 985                         $msg['parent-uri'] = $item['thr-parent'];
 986
 987                         if (!empty($item['title'])) {
 988                                 $msg['title'] = $item['title'];
 989                         } elseif (!empty($item['content-warning'])) {
 990                                 $msg['title'] = $item['content-warning'];
 991                         } else {
 992                                 // Trying to generate a title out of the body
 993                                 $title = $item['body'];
 994
 995                                 while (preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $title, $matches)) {
 996                                         $title = $matches[3];
 997                                 }
 998
 999                                 $title = trim(BBCode::toPlaintext($title));
1000
1001                                 if (strlen($title) > 20) {
1002                                         $title = substr($title, 0, 20) . '...';
1003                                 }
1004
1005                                 $msg['title'] = $title;
1006                         }
1007                 }
1008                 $msg['body'] = $item['body'];
1009
1010                 return Mail::insert($msg);
1011         }
1012
1013         /**
1014          * Fetch featured posts from a contact with the given url
1015          *
1016          * @param string $url
1017          * @return void
1018          */
1019         public static function fetchFeaturedPosts(string $url)
1020         {
1021                 Logger::info('Fetch featured posts', ['contact' => $url]);
1022
1023                 $apcontact = APContact::getByURL($url);
1024                 if (empty($apcontact['featured'])) {
1025                         Logger::info('Contact does not have a featured collection', ['contact' => $url]);
1026                         return;
1027                 }
1028
1029                 $pcid = Contact::getIdForURL($url, 0, false);
1030                 if (empty($pcid)) {
1031                         Logger::info('Contact not found', ['contact' => $url]);
1032                         return;
1033                 }
1034
1035                 $posts = Post\Collection::selectToArrayForContact($pcid, Post\Collection::FEATURED);
1036                 if (!empty($posts)) {
1037                         $old_featured = array_column($posts, 'uri-id');
1038                 } else {
1039                         $old_featured = [];
1040                 }
1041
1042                 $featured = ActivityPub::fetchItems($apcontact['featured']);
1043                 if (empty($featured)) {
1044                         Logger::info('Contact does not have featured posts', ['contact' => $url]);
1045
1046                         foreach ($old_featured as $uri_id) {
1047                                 Post\Collection::remove($uri_id, Post\Collection::FEATURED);
1048                                 Logger::debug('Removed no longer featured post', ['uri-id' => $uri_id, 'contact' => $url]);
1049                         }
1050                         return;
1051                 }
1052
1053                 $new = 0;
1054                 $old = 0;
1055
1056                 foreach ($featured as $post) {
1057                         if (empty($post['id'])) {
1058                                 continue;
1059                         }
1060                         $id = Item::fetchByLink($post['id']);
1061                         if (!empty($id)) {
1062                                 $item = Post::selectFirst(['uri-id', 'featured'], ['id' => $id]);
1063                                 if (!empty($item['uri-id'])) {
1064                                         if (!$item['featured']) {
1065                                                 Post\Collection::add($item['uri-id'], Post\Collection::FEATURED);
1066                                                 Logger::debug('Added featured post', ['uri-id' => $item['uri-id'], 'contact' => $url]);
1067                                                 $new++;
1068                                         } else {
1069                                                 Logger::debug('Post already had been featured', ['uri-id' => $item['uri-id'], 'contact' => $url]);
1070                                                 $old++;
1071                                         }
1072
1073                                         $index = array_search($item['uri-id'], $old_featured);
1074                                         if (!($index === false)) {
1075                                                 unset($old_featured[$index]);
1076                                         }
1077                                 }
1078                         }
1079                 }
1080
1081                 foreach ($old_featured as $uri_id) {
1082                         Post\Collection::remove($uri_id, Post\Collection::FEATURED);
1083                         Logger::debug('Removed no longer featured post', ['uri-id' => $uri_id, 'contact' => $url]);
1084                 }
1085
1086                 Logger::info('Fetched featured posts', ['new' => $new, 'old' => $old, 'contact' => $url]);
1087         }
1088
1089         /**
1090          * Fetches missing posts
1091          *
1092          * @param string $url         message URL
1093          * @param array  $child       activity array with the child of this message
1094          * @param string $relay_actor Relay actor
1095          * @param int    $completion  Completion mode, see Receiver::COMPLETION_*
1096          * @return string fetched message URL
1097          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1098          */
1099         public static function fetchMissingActivity(string $url, array $child = [], string $relay_actor = '', int $completion = Receiver::COMPLETION_MANUAL)
1100         {
1101                 if (!empty($child['receiver'])) {
1102                         $uid = ActivityPub\Receiver::getFirstUserFromReceivers($child['receiver']);
1103                 } else {
1104                         $uid = 0;
1105                 }
1106
1107                 $object = ActivityPub::fetchContent($url, $uid);
1108                 if (empty($object)) {
1109                         Logger::notice('Activity was not fetchable, aborting.', ['url' => $url]);
1110                         return '';
1111                 }
1112
1113                 if (empty($object['id'])) {
1114                         Logger::notice('Activity has got not id, aborting. ', ['url' => $url, 'object' => $object]);
1115                         return '';
1116                 }
1117
1118                 if (!empty($object['actor'])) {
1119                         $object_actor = $object['actor'];
1120                 } elseif (!empty($object['attributedTo'])) {
1121                         $object_actor = $object['attributedTo'];
1122                         if (is_array($object_actor)) {
1123                                 $compacted = JsonLD::compact($object);
1124                                 $object_actor = JsonLD::fetchElement($compacted, 'as:attributedTo', '@id');
1125                         }
1126                 } else {
1127                         // Shouldn't happen
1128                         $object_actor = '';
1129                 }
1130
1131                 $signer = [$object_actor];
1132
1133                 if (!empty($child['author'])) {
1134                         $actor = $child['author'];
1135                         $signer[] = $actor;
1136                 } else {
1137                         $actor = $object_actor;
1138                 }
1139
1140                 if (!empty($object['published'])) {
1141                         $published = $object['published'];
1142                 } elseif (!empty($child['published'])) {
1143                         $published = $child['published'];
1144                 } else {
1145                         $published = DateTimeFormat::utcNow();
1146                 }
1147
1148                 $activity = [];
1149                 $activity['@context'] = $object['@context'] ?? ActivityPub::CONTEXT;
1150                 unset($object['@context']);
1151                 $activity['id'] = $object['id'];
1152                 $activity['to'] = $object['to'] ?? [];
1153                 $activity['cc'] = $object['cc'] ?? [];
1154                 $activity['actor'] = $actor;
1155                 $activity['object'] = $object;
1156                 $activity['published'] = $published;
1157                 $activity['type'] = 'Create';
1158
1159                 $ldactivity = JsonLD::compact($activity);
1160
1161                 if (!empty($relay_actor)) {
1162                         $ldactivity['thread-completion'] = $ldactivity['from-relay'] = Contact::getIdForURL($relay_actor);
1163                         $ldactivity['completion-mode']   = Receiver::COMPLETION_RELAY;
1164                 } elseif (!empty($child['thread-completion'])) {
1165                         $ldactivity['thread-completion'] = $child['thread-completion'];
1166                         $ldactivity['completion-mode']   = $child['completion-mode'] ?? Receiver::COMPLETION_NONE;
1167                 } else {
1168                         $ldactivity['thread-completion'] = Contact::getIdForURL($actor);
1169                         $ldactivity['completion-mode']   = $completion;
1170                 }
1171
1172                 if (!empty($child['type'])) {
1173                         $ldactivity['thread-children-type'] = $child['type'];
1174                 }
1175
1176                 if (!empty($relay_actor) && !self::acceptIncomingMessage($ldactivity, $object['id'])) {
1177                         return '';
1178                 }
1179
1180                 ActivityPub\Receiver::processActivity($ldactivity, json_encode($activity), $uid, true, false, $signer);
1181
1182                 Logger::notice('Activity had been fetched and processed.', ['url' => $url, 'object' => $activity['id']]);
1183
1184                 return $activity['id'];
1185         }
1186
1187         /**
1188          * Test if incoming relay messages should be accepted
1189          *
1190          * @param array $activity activity array
1191          * @param string $id      object ID
1192          * @return boolean true if message is accepted
1193          */
1194         private static function acceptIncomingMessage(array $activity, string $id)
1195         {
1196                 if (empty($activity['as:object'])) {
1197                         Logger::info('No object field in activity - accepted', ['id' => $id]);
1198                         return true;
1199                 }
1200
1201                 $replyto = JsonLD::fetchElement($activity['as:object'], 'as:inReplyTo', '@id');
1202                 $uriid = ItemURI::getIdByURI($replyto);
1203                 if (Post::exists(['uri-id' => $uriid])) {
1204                         Logger::info('Post is a reply to an existing post - accepted', ['id' => $id, 'uri-id' => $uriid, 'replyto' => $replyto]);
1205                         return true;
1206                 }
1207
1208                 $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
1209                 $authorid = Contact::getIdForURL($attributed_to);
1210
1211                 $body = HTML::toBBCode(JsonLD::fetchElement($activity['as:object'], 'as:content', '@value'));
1212
1213                 $messageTags = [];
1214                 $tags = Receiver::processTags(JsonLD::fetchElementArray($activity['as:object'], 'as:tag') ?? []);
1215                 if (!empty($tags)) {
1216                         foreach ($tags as $tag) {
1217                                 if ($tag['type'] != 'Hashtag') {
1218                                         continue;
1219                                 }
1220                                 $messageTags[] = ltrim(mb_strtolower($tag['name']), '#');
1221                         }
1222                 }
1223
1224                 return Relay::isSolicitedPost($messageTags, $body, $authorid, $id, Protocol::ACTIVITYPUB);
1225         }
1226
1227         /**
1228          * perform a "follow" request
1229          *
1230          * @param array $activity
1231          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1232          * @throws \ImagickException
1233          */
1234         public static function followUser($activity)
1235         {
1236                 $uid = User::getIdForURL($activity['object_id']);
1237                 if (empty($uid)) {
1238                         return;
1239                 }
1240
1241                 $owner = User::getOwnerDataById($uid);
1242                 if (empty($owner)) {
1243                         return;
1244                 }
1245
1246                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1247                 if (!empty($cid)) {
1248                         self::switchContact($cid);
1249                         Contact::update(['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
1250                 }
1251
1252                 $item = ['author-id' => Contact::getIdForURL($activity['actor']),
1253                         'author-link' => $activity['actor']];
1254
1255                 // Ensure that the contact has got the right network type
1256                 self::switchContact($item['author-id']);
1257
1258                 $result = Contact::addRelationship($owner, [], $item, false, $activity['content'] ?? '');
1259                 if ($result === true) {
1260                         ActivityPub\Transmitter::sendContactAccept($item['author-link'], $activity['id'], $owner['uid']);
1261                 }
1262
1263                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1264                 if (empty($cid)) {
1265                         return;
1266                 }
1267
1268                 if (empty($contact)) {
1269                         Contact::update(['hub-verify' => $activity['id'], 'protocol' => Protocol::ACTIVITYPUB], ['id' => $cid]);
1270                 }
1271
1272                 Logger::notice('Follow user ' . $uid . ' from contact ' . $cid . ' with id ' . $activity['id']);
1273         }
1274
1275         /**
1276          * Update the given profile
1277          *
1278          * @param array $activity
1279          * @throws \Exception
1280          */
1281         public static function updatePerson($activity)
1282         {
1283                 if (empty($activity['object_id'])) {
1284                         return;
1285                 }
1286
1287                 Logger::info('Updating profile', ['object' => $activity['object_id']]);
1288                 Contact::updateFromProbeByURL($activity['object_id']);
1289         }
1290
1291         /**
1292          * Delete the given profile
1293          *
1294          * @param array $activity
1295          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1296          */
1297         public static function deletePerson($activity)
1298         {
1299                 if (empty($activity['object_id']) || empty($activity['actor'])) {
1300                         Logger::info('Empty object id or actor.');
1301                         return;
1302                 }
1303
1304                 if ($activity['object_id'] != $activity['actor']) {
1305                         Logger::info('Object id does not match actor.');
1306                         return;
1307                 }
1308
1309                 $contacts = DBA::select('contact', ['id'], ['nurl' => Strings::normaliseLink($activity['object_id'])]);
1310                 while ($contact = DBA::fetch($contacts)) {
1311                         Contact::remove($contact['id']);
1312                 }
1313                 DBA::close($contacts);
1314
1315                 Logger::info('Deleted contact', ['object' => $activity['object_id']]);
1316         }
1317
1318         /**
1319          * Blocks the user by the contact
1320          *
1321          * @param array $activity
1322          * @throws \Exception
1323          */
1324         public static function blockAccount($activity)
1325         {
1326                 $cid = Contact::getIdForURL($activity['actor']);
1327                 if (empty($cid)) {
1328                         return;
1329                 }
1330
1331                 $uid = User::getIdForURL($activity['object_id']);
1332                 if (empty($uid)) {
1333                         return;
1334                 }
1335
1336                 Contact\User::setIsBlocked($cid, $uid, true);
1337
1338                 Logger::info('Contact blocked user', ['contact' => $cid, 'user' => $uid]);
1339         }
1340
1341         /**
1342          * Unblocks the user by the contact
1343          *
1344          * @param array $activity
1345          * @throws \Exception
1346          */
1347         public static function unblockAccount($activity)
1348         {
1349                 $cid = Contact::getIdForURL($activity['actor']);
1350                 if (empty($cid)) {
1351                         return;
1352                 }
1353
1354                 $uid = User::getIdForURL($activity['object_object']);
1355                 if (empty($uid)) {
1356                         return;
1357                 }
1358
1359                 Contact\User::setIsBlocked($cid, $uid, false);
1360
1361                 Logger::info('Contact unblocked user', ['contact' => $cid, 'user' => $uid]);
1362         }
1363
1364         /**
1365          * Accept a follow request
1366          *
1367          * @param array $activity
1368          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1369          * @throws \ImagickException
1370          */
1371         public static function acceptFollowUser($activity)
1372         {
1373                 $uid = User::getIdForURL($activity['object_actor']);
1374                 if (empty($uid)) {
1375                         return;
1376                 }
1377
1378                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1379                 if (empty($cid)) {
1380                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1381                         return;
1382                 }
1383
1384                 self::switchContact($cid);
1385
1386                 $fields = ['pending' => false];
1387
1388                 $contact = DBA::selectFirst('contact', ['rel'], ['id' => $cid]);
1389                 if ($contact['rel'] == Contact::FOLLOWER) {
1390                         $fields['rel'] = Contact::FRIEND;
1391                 }
1392
1393                 $condition = ['id' => $cid];
1394                 Contact::update($fields, $condition);
1395                 Logger::info('Accept contact request', ['contact' => $cid, 'user' => $uid]);
1396         }
1397
1398         /**
1399          * Reject a follow request
1400          *
1401          * @param array $activity
1402          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1403          * @throws \ImagickException
1404          */
1405         public static function rejectFollowUser($activity)
1406         {
1407                 $uid = User::getIdForURL($activity['object_actor']);
1408                 if (empty($uid)) {
1409                         return;
1410                 }
1411
1412                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1413                 if (empty($cid)) {
1414                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1415                         return;
1416                 }
1417
1418                 self::switchContact($cid);
1419
1420                 $contact = Contact::getById($cid, ['rel']);
1421                 if ($contact['rel'] == Contact::SHARING) {
1422                         Contact::remove($cid);
1423                         Logger::info('Rejected contact request - contact removed', ['contact' => $cid, 'user' => $uid]);
1424                 } elseif ($contact['rel'] == Contact::FRIEND) {
1425                         Contact::update(['rel' => Contact::FOLLOWER], ['id' => $cid]);
1426                 } else {
1427                         Logger::info('Rejected contact request', ['contact' => $cid, 'user' => $uid]);
1428                 }
1429         }
1430
1431         /**
1432          * Undo activity like "like" or "dislike"
1433          *
1434          * @param array $activity
1435          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1436          * @throws \ImagickException
1437          */
1438         public static function undoActivity($activity)
1439         {
1440                 if (empty($activity['object_id'])) {
1441                         return;
1442                 }
1443
1444                 if (empty($activity['object_actor'])) {
1445                         return;
1446                 }
1447
1448                 $author_id = Contact::getIdForURL($activity['object_actor']);
1449                 if (empty($author_id)) {
1450                         return;
1451                 }
1452
1453                 Item::markForDeletion(['uri' => $activity['object_id'], 'author-id' => $author_id, 'gravity' => GRAVITY_ACTIVITY]);
1454         }
1455
1456         /**
1457          * Activity to remove a follower
1458          *
1459          * @param array $activity
1460          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1461          * @throws \ImagickException
1462          */
1463         public static function undoFollowUser($activity)
1464         {
1465                 $uid = User::getIdForURL($activity['object_object']);
1466                 if (empty($uid)) {
1467                         return;
1468                 }
1469
1470                 $owner = User::getOwnerDataById($uid);
1471                 if (empty($owner)) {
1472                         return;
1473                 }
1474
1475                 $cid = Contact::getIdForURL($activity['actor'], $uid);
1476                 if (empty($cid)) {
1477                         Logger::info('No contact found', ['actor' => $activity['actor']]);
1478                         return;
1479                 }
1480
1481                 self::switchContact($cid);
1482
1483                 $contact = DBA::selectFirst('contact', [], ['id' => $cid]);
1484                 if (!DBA::isResult($contact)) {
1485                         return;
1486                 }
1487
1488                 Contact::removeFollower($contact);
1489                 Logger::info('Undo following request', ['contact' => $cid, 'user' => $uid]);
1490         }
1491
1492         /**
1493          * Switches a contact to AP if needed
1494          *
1495          * @param integer $cid Contact ID
1496          * @throws \Exception
1497          */
1498         private static function switchContact($cid)
1499         {
1500                 $contact = DBA::selectFirst('contact', ['network', 'url'], ['id' => $cid]);
1501                 if (!DBA::isResult($contact) || in_array($contact['network'], [Protocol::ACTIVITYPUB, Protocol::DFRN]) || Contact::isLocal($contact['url'])) {
1502                         return;
1503                 }
1504
1505                 Logger::info('Change existing contact', ['cid' => $cid, 'previous' => $contact['network']]);
1506                 Contact::updateFromProbe($cid);
1507         }
1508
1509         /**
1510          * Collects implicit mentions like:
1511          * - the author of the parent item
1512          * - all the mentioned conversants in the parent item
1513          *
1514          * @param array $parent Item array with at least ['id', 'author-link', 'alias']
1515          * @return array
1516          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1517          */
1518         private static function getImplicitMentionList(array $parent)
1519         {
1520                 $parent_terms = Tag::getByURIId($parent['uri-id'], [Tag::MENTION, Tag::IMPLICIT_MENTION, Tag::EXCLUSIVE_MENTION]);
1521
1522                 $parent_author = Contact::getByURL($parent['author-link'], false, ['url', 'nurl', 'alias']);
1523
1524                 $implicit_mentions = [];
1525                 if (empty($parent_author['url'])) {
1526                         Logger::notice('Author public contact unknown.', ['author-link' => $parent['author-link'], 'parent-id' => $parent['id']]);
1527                 } else {
1528                         $implicit_mentions[] = $parent_author['url'];
1529                         $implicit_mentions[] = $parent_author['nurl'];
1530                         $implicit_mentions[] = $parent_author['alias'];
1531                 }
1532
1533                 if (!empty($parent['alias'])) {
1534                         $implicit_mentions[] = $parent['alias'];
1535                 }
1536
1537                 foreach ($parent_terms as $term) {
1538                         $contact = Contact::getByURL($term['url'], false, ['url', 'nurl', 'alias']);
1539                         if (!empty($contact['url'])) {
1540                                 $implicit_mentions[] = $contact['url'];
1541                                 $implicit_mentions[] = $contact['nurl'];
1542                                 $implicit_mentions[] = $contact['alias'];
1543                         }
1544                 }
1545
1546                 return $implicit_mentions;
1547         }
1548
1549         /**
1550          * Strips from the body prepended implicit mentions
1551          *
1552          * @param string $body
1553          * @param array $parent
1554          * @return string
1555          */
1556         private static function removeImplicitMentionsFromBody(string $body, array $parent)
1557         {
1558                 if (DI::config()->get('system', 'disable_implicit_mentions')) {
1559                         return $body;
1560                 }
1561
1562                 $potential_mentions = self::getImplicitMentionList($parent);
1563
1564                 $kept_mentions = [];
1565
1566                 // Extract one prepended mention at a time from the body
1567                 while(preg_match('#^(@\[url=([^\]]+)].*?\[\/url]\s)(.*)#is', $body, $matches)) {
1568                         if (!in_array($matches[2], $potential_mentions)) {
1569                                 $kept_mentions[] = $matches[1];
1570                         }
1571
1572                         $body = $matches[3];
1573                 }
1574
1575                 // Re-appending the kept mentions to the body after extraction
1576                 $kept_mentions[] = $body;
1577
1578                 return implode('', $kept_mentions);
1579         }
1580
1581         /**
1582          * Adds links to string mentions
1583          *
1584          * @param string $body
1585          * @param array  $tags
1586          * @return string
1587          */
1588         protected static function addMentionLinks(string $body, array $tags): string
1589         {
1590                 // This prevents links to be added again to Pleroma-style mention links
1591                 $body = self::normalizeMentionLinks($body);
1592
1593                 $body = BBCode::performWithEscapedTags($body, ['url'], function ($body) use ($tags) {
1594                         foreach ($tags as $tag) {
1595                                 if (empty($tag['name']) || empty($tag['type']) || empty($tag['href']) || !in_array($tag['type'], ['Mention', 'Hashtag'])) {
1596                                         continue;
1597                                 }
1598
1599                                 $hash = substr($tag['name'], 0, 1);
1600                                 $name = substr($tag['name'], 1);
1601                                 if (!in_array($hash, Tag::TAG_CHARACTER)) {
1602                                         $hash = '';
1603                                         $name = $tag['name'];
1604                                 }
1605
1606                                 $body = str_replace($tag['name'], $hash . '[url=' . $tag['href'] . ']' . $name . '[/url]', $body);
1607                         }
1608
1609                         return $body;
1610                 });
1611
1612                 return $body;
1613         }
1614 }