src/Protocol/ActivityPub/Receiver.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2020, Friendica
   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\Database\DBA;
  26 use Friendica\Content\Text\HTML;
  27 use Friendica\Content\Text\Markdown;
  28 use Friendica\Core\Logger;
  29 use Friendica\Core\Protocol;
  30 use Friendica\Model\Contact;
  31 use Friendica\Model\APContact;
  32 use Friendica\Model\Item;
  33 use Friendica\Model\User;
  34 use Friendica\Protocol\Activity;
  35 use Friendica\Protocol\ActivityPub;
  36 use Friendica\Util\HTTPSignature;
  37 use Friendica\Util\JsonLD;
  38 use Friendica\Util\LDSignature;
  39 use Friendica\Util\Strings;
  40
  41 /**
  42  * ActivityPub Receiver Protocol class
  43  *
  44  * To-Do:
  45  * @todo Undo Announce
  46  *
  47  * Check what this is meant to do:
  48  * - Add
  49  * - Block
  50  * - Flag
  51  * - Remove
  52  * - Undo Block
  53  */
  54 class Receiver
  55 {
  56         const PUBLIC_COLLECTION = 'as:Public';
  57         const ACCOUNT_TYPES = ['as:Person', 'as:Organization', 'as:Service', 'as:Group', 'as:Application'];
  58         const CONTENT_TYPES = ['as:Note', 'as:Article', 'as:Video', 'as:Image', 'as:Event', 'as:Audio'];
  59         const ACTIVITY_TYPES = ['as:Like', 'as:Dislike', 'as:Accept', 'as:Reject', 'as:TentativeAccept'];
  60
  61         const TARGET_UNKNOWN = 0;
  62         const TARGET_TO = 1;
  63         const TARGET_CC = 2;
  64         const TARGET_BCC = 3;
  65         const TARGET_FOLLOWER = 4;
  66
  67         /**
  68          * Checks if the web request is done for the AP protocol
  69          *
  70          * @return bool is it AP?
  71          */
  72         public static function isRequest()
  73         {
  74                 return stristr($_SERVER['HTTP_ACCEPT'] ?? '', 'application/activity+json') ||
  75                         stristr($_SERVER['HTTP_ACCEPT'] ?? '', 'application/ld+json');
  76         }
  77
  78         /**
  79          * Checks incoming message from the inbox
  80          *
  81          * @param         $body
  82          * @param         $header
  83          * @param integer $uid User ID
  84          * @throws \Exception
  85          */
  86         public static function processInbox($body, $header, $uid)
  87         {
  88                 $http_signer = HTTPSignature::getSigner($body, $header);
  89                 if (empty($http_signer)) {
  90                         Logger::warning('Invalid HTTP signature, message will be discarded.');
  91                         return;
  92                 } else {
  93                         Logger::info('Valid HTTP signature', ['signer' => $http_signer]);
  94                 }
  95
  96                 $signer = [$http_signer];
  97                 $activity = json_decode($body, true);
  98
  99                 if (empty($activity)) {
 100                         Logger::warning('Invalid body.');
 101                         return;
 102                 }
 103
 104                 $ldactivity = JsonLD::compact($activity);
 105
 106                 $actor = JsonLD::fetchElement($ldactivity, 'as:actor', '@id');
 107
 108                 Logger::info('Message for user ' . $uid . ' is from actor ' . $actor);
 109
 110                 if (LDSignature::isSigned($activity)) {
 111                         $ld_signer = LDSignature::getSigner($activity);
 112                         if (empty($ld_signer)) {
 113                                 Logger::log('Invalid JSON-LD signature from ' . $actor, Logger::DEBUG);
 114                         } elseif ($ld_signer != $http_signer) {
 115                                 $signer[] = $ld_signer;
 116                         }
 117                         if (!empty($ld_signer && ($actor == $http_signer))) {
 118                                 Logger::log('The HTTP and the JSON-LD signature belong to ' . $ld_signer, Logger::DEBUG);
 119                                 $trust_source = true;
 120                         } elseif (!empty($ld_signer)) {
 121                                 Logger::log('JSON-LD signature is signed by ' . $ld_signer, Logger::DEBUG);
 122                                 $trust_source = true;
 123                         } elseif ($actor == $http_signer) {
 124                                 Logger::log('Bad JSON-LD signature, but HTTP signer fits the actor.', Logger::DEBUG);
 125                                 $trust_source = true;
 126                         } else {
 127                                 Logger::log('Invalid JSON-LD signature and the HTTP signer is different.', Logger::DEBUG);
 128                                 $trust_source = false;
 129                         }
 130                 } elseif ($actor == $http_signer) {
 131                         Logger::log('Trusting post without JSON-LD signature, The actor fits the HTTP signer.', Logger::DEBUG);
 132                         $trust_source = true;
 133                 } else {
 134                         Logger::log('No JSON-LD signature, different actor.', Logger::DEBUG);
 135                         $trust_source = false;
 136                 }
 137
 138                 self::processActivity($ldactivity, $body, $uid, $trust_source, true, $signer);
 139         }
 140
 141         /**
 142          * Fetches the object type for a given object id
 143          *
 144          * @param array   $activity
 145          * @param string  $object_id Object ID of the the provided object
 146          * @param integer $uid       User ID
 147          *
 148          * @return string with object type
 149          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 150          * @throws \ImagickException
 151          */
 152         private static function fetchObjectType($activity, $object_id, $uid = 0)
 153         {
 154                 if (!empty($activity['as:object'])) {
 155                         $object_type = JsonLD::fetchElement($activity['as:object'], '@type');
 156                         if (!empty($object_type)) {
 157                                 return $object_type;
 158                         }
 159                 }
 160
 161                 if (Item::exists(['uri' => $object_id, 'gravity' => [GRAVITY_PARENT, GRAVITY_COMMENT]])) {
 162                         // We just assume "note" since it doesn't make a difference for the further processing
 163                         return 'as:Note';
 164                 }
 165
 166                 $profile = APContact::getByURL($object_id);
 167                 if (!empty($profile['type'])) {
 168                         return 'as:' . $profile['type'];
 169                 }
 170
 171                 $data = ActivityPub::fetchContent($object_id, $uid);
 172                 if (!empty($data)) {
 173                         $object = JsonLD::compact($data);
 174                         $type = JsonLD::fetchElement($object, '@type');
 175                         if (!empty($type)) {
 176                                 return $type;
 177                         }
 178                 }
 179
 180                 return null;
 181         }
 182
 183         /**
 184          * Prepare the object array
 185          *
 186          * @param array   $activity     Array with activity data
 187          * @param integer $uid          User ID
 188          * @param boolean $push         Message had been pushed to our system
 189          * @param boolean $trust_source Do we trust the source?
 190          *
 191          * @return array with object data
 192          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 193          * @throws \ImagickException
 194          */
 195         public static function prepareObjectData($activity, $uid, $push, &$trust_source)
 196         {
 197                 $id = JsonLD::fetchElement($activity, '@id');
 198                 if (!empty($id) && !$trust_source) {
 199                         $fetched_activity = ActivityPub::fetchContent($id, $uid ?? 0);
 200                         if (!empty($fetched_activity)) {
 201                                 $object = JsonLD::compact($fetched_activity);
 202                                 $fetched_id = JsonLD::fetchElement($object, '@id');
 203                                 if ($fetched_id == $id) {
 204                                         Logger::info('Activity had been fetched successfully', ['id' => $id]);
 205                                         $trust_source = true;
 206                                         $activity = $object;
 207                                 } else {
 208                                         Logger::info('Activity id is not equal', ['id' => $id, 'fetched' => $fetched_id]);
 209                                 }
 210                         } else {
 211                                 Logger::info('Activity could not been fetched', ['id' => $id]);
 212                         }
 213                 }
 214
 215                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 216                 if (empty($actor)) {
 217                         Logger::info('Empty actor', ['activity' => $activity]);
 218                         return [];
 219                 }
 220
 221                 $type = JsonLD::fetchElement($activity, '@type');
 222
 223                 // Fetch all receivers from to, cc, bto and bcc
 224                 $receivers = self::getReceivers($activity, $actor);
 225                 $reception_type = [];
 226
 227                 // When it is a delivery to a personal inbox we add that user to the receivers
 228                 if (!empty($uid)) {
 229                         $reception_type[$uid] = self::TARGET_BCC;
 230                         $additional = ['uid:' . $uid => $uid];
 231                         $receivers = array_merge($receivers, $additional);
 232                 } else {
 233                         // We possibly need some user to fetch private content,
 234                         // so we fetch the first out ot the list.
 235                         $uid = self::getFirstUserFromReceivers($receivers);
 236                 }
 237
 238                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 239                 if (empty($object_id)) {
 240                         Logger::log('No object found', Logger::DEBUG);
 241                         return [];
 242                 }
 243
 244                 if (!is_string($object_id)) {
 245                         Logger::info('Invalid object id', ['object' => $object_id]);
 246                         return [];
 247                 }
 248
 249                 $object_type = self::fetchObjectType($activity, $object_id, $uid);
 250
 251                 // Fetch the content only on activities where this matters
 252                 if (in_array($type, ['as:Create', 'as:Update', 'as:Announce'])) {
 253                         // Always fetch on "Announce"
 254                         $object_data = self::fetchObject($object_id, $activity['as:object'], $trust_source && ($type != 'as:Announce'), $uid);
 255                         if (empty($object_data)) {
 256                                 Logger::log("Object data couldn't be processed", Logger::DEBUG);
 257                                 return [];
 258                         }
 259
 260                         $object_data['object_id'] = $object_id;
 261
 262                         if ($type == 'as:Announce') {
 263                                 $object_data['push'] = false;
 264                         } else {
 265                                 $object_data['push'] = $push;
 266                         }
 267
 268                         // Test if it is an answer to a mail
 269                         if (DBA::exists('mail', ['uri' => $object_data['reply-to-id']])) {
 270                                 $object_data['directmessage'] = true;
 271                         } else {
 272                                 $object_data['directmessage'] = JsonLD::fetchElement($activity, 'litepub:directMessage');
 273                         }
 274                 } elseif (in_array($type, array_merge(self::ACTIVITY_TYPES, ['as:Follow'])) && in_array($object_type, self::CONTENT_TYPES)) {
 275                         // Create a mostly empty array out of the activity data (instead of the object).
 276                         // This way we later don't have to check for the existence of ech individual array element.
 277                         $object_data = self::processObject($activity);
 278                         $object_data['name'] = $type;
 279                         $object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 280                         $object_data['object_id'] = $object_id;
 281                         $object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
 282                 } elseif (in_array($type, ['as:Add'])) {
 283                         $object_data = [];
 284                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 285                         $object_data['target_id'] = JsonLD::fetchElement($activity, 'as:target', '@id');
 286                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 287                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 288                         $object_data['object_content'] = JsonLD::fetchElement($activity['as:object'], 'as:content', '@type');
 289                 } else {
 290                         $object_data = [];
 291                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 292                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 293                         $object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor', '@id');
 294                         $object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
 295                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 296
 297                         // An Undo is done on the object of an object, so we need that type as well
 298                         if (($type == 'as:Undo') && !empty($object_data['object_object'])) {
 299                                 $object_data['object_object_type'] = self::fetchObjectType([], $object_data['object_object'], $uid);
 300                         }
 301                 }
 302
 303                 $object_data = self::addActivityFields($object_data, $activity);
 304
 305                 if (empty($object_data['object_type'])) {
 306                         $object_data['object_type'] = $object_type;
 307                 }
 308
 309                 $object_data['type'] = $type;
 310                 $object_data['actor'] = $actor;
 311                 $object_data['item_receiver'] = $receivers;
 312                 $object_data['receiver'] = array_merge($object_data['receiver'] ?? [], $receivers);
 313                 $object_data['reception_type'] = $reception_type;
 314
 315                 $author = $object_data['author'] ?? $actor;
 316                 if (!empty($author) && !empty($object_data['id'])) {
 317                         $author_host = parse_url($author, PHP_URL_HOST);
 318                         $id_host = parse_url($object_data['id'], PHP_URL_HOST);
 319                         if ($author_host == $id_host) {
 320                                 Logger::info('Valid hosts', ['type' => $type, 'host' => $id_host]);
 321                         } else {
 322                                 Logger::notice('Differing hosts on author and id', ['type' => $type, 'author' => $author_host, 'id' => $id_host]);
 323                                 $trust_source = false;
 324                         }
 325                 }
 326
 327                 Logger::log('Processing ' . $object_data['type'] . ' ' . $object_data['object_type'] . ' ' . $object_data['id'], Logger::DEBUG);
 328
 329                 return $object_data;
 330         }
 331
 332         /**
 333          * Fetches the first user id from the receiver array
 334          *
 335          * @param array $receivers Array with receivers
 336          * @return integer user id;
 337          */
 338         public static function getFirstUserFromReceivers($receivers)
 339         {
 340                 foreach ($receivers as $receiver) {
 341                         if (!empty($receiver)) {
 342                                 return $receiver;
 343                         }
 344                 }
 345                 return 0;
 346         }
 347
 348         /**
 349          * Processes the activity object
 350          *
 351          * @param array   $activity     Array with activity data
 352          * @param string  $body
 353          * @param integer $uid          User ID
 354          * @param boolean $trust_source Do we trust the source?
 355          * @param boolean $push         Message had been pushed to our system
 356          * @throws \Exception
 357          */
 358         public static function processActivity($activity, string $body = '', int $uid = null, bool $trust_source = false, bool $push = false, array $signer = [])
 359         {
 360                 $type = JsonLD::fetchElement($activity, '@type');
 361                 if (!$type) {
 362                         Logger::info('Empty type', ['activity' => $activity]);
 363                         return;
 364                 }
 365
 366                 if (!JsonLD::fetchElement($activity, 'as:object', '@id')) {
 367                         Logger::info('Empty object', ['activity' => $activity]);
 368                         return;
 369                 }
 370
 371                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 372                 if (empty($actor)) {
 373                         Logger::info('Empty actor', ['activity' => $activity]);
 374                         return;
 375                 }
 376
 377                 if (is_array($activity['as:object'])) {
 378                         $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
 379                 } else {
 380                         $attributed_to = '';
 381                 }
 382
 383                 // Test the provided signatures against the actor and "attributedTo"
 384                 if ($trust_source) {
 385                         if (!empty($attributed_to) && !empty($actor)) {
 386                                 $trust_source = (in_array($actor, $signer) && in_array($attributed_to, $signer));
 387                         } else {
 388                                 $trust_source = in_array($actor, $signer);
 389                         }
 390                 }
 391
 392                 // $trust_source is called by reference and is set to true if the content was retrieved successfully
 393                 $object_data = self::prepareObjectData($activity, $uid, $push, $trust_source);
 394                 if (empty($object_data)) {
 395                         Logger::info('No object data found', ['activity' => $activity]);
 396                         return;
 397                 }
 398
 399                 if (!$trust_source) {
 400                         Logger::info('Activity trust could not be achieved.',  ['id' => $object_data['object_id'], 'type' => $type, 'signer' => $signer, 'actor' => $actor, 'attributedTo' => $attributed_to]);
 401                         return;
 402                 }
 403
 404                 if (!empty($body) && empty($object_data['raw'])) {
 405                         $object_data['raw'] = $body;
 406                 }
 407
 408                 // Internal flag for thread completion. See Processor.php
 409                 if (!empty($activity['thread-completion'])) {
 410                         $object_data['thread-completion'] = $activity['thread-completion'];
 411                 }
 412
 413                 switch ($type) {
 414                         case 'as:Create':
 415                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 416                                         $item = ActivityPub\Processor::createItem($object_data);
 417                                         ActivityPub\Processor::postItem($object_data, $item);
 418                                 }
 419                                 break;
 420
 421                         case 'as:Add':
 422                                 if ($object_data['object_type'] == 'as:tag') {
 423                                         ActivityPub\Processor::addTag($object_data);
 424                                 }
 425                                 break;
 426
 427                         case 'as:Announce':
 428                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 429                                         $object_data['thread-completion'] = true;
 430
 431                                         $item = ActivityPub\Processor::createItem($object_data);
 432                                         ActivityPub\Processor::postItem($object_data, $item);
 433
 434                                         $announce_object_data = self::processObject($activity);
 435                                         $announce_object_data['name'] = $type;
 436                                         $announce_object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 437                                         $announce_object_data['object_id'] = $object_data['object_id'];
 438                                         $announce_object_data['object_type'] = $object_data['object_type'];
 439                                         $announce_object_data['push'] = $push;
 440
 441                                         if (!empty($body)) {
 442                                                 $announce_object_data['raw'] = $body;
 443                                         }
 444
 445                                         ActivityPub\Processor::createActivity($announce_object_data, Activity::ANNOUNCE);
 446                                 }
 447                                 break;
 448
 449                         case 'as:Like':
 450                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 451                                         ActivityPub\Processor::createActivity($object_data, Activity::LIKE);
 452                                 }
 453                                 break;
 454
 455                         case 'as:Dislike':
 456                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 457                                         ActivityPub\Processor::createActivity($object_data, Activity::DISLIKE);
 458                                 }
 459                                 break;
 460
 461                         case 'as:TentativeAccept':
 462                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 463                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDMAYBE);
 464                                 }
 465                                 break;
 466
 467                         case 'as:Update':
 468                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 469                                         ActivityPub\Processor::updateItem($object_data);
 470                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 471                                         ActivityPub\Processor::updatePerson($object_data);
 472                                 }
 473                                 break;
 474
 475                         case 'as:Delete':
 476                                 if ($object_data['object_type'] == 'as:Tombstone') {
 477                                         ActivityPub\Processor::deleteItem($object_data);
 478                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 479                                         ActivityPub\Processor::deletePerson($object_data);
 480                                 }
 481                                 break;
 482
 483                         case 'as:Follow':
 484                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 485                                         ActivityPub\Processor::followUser($object_data);
 486                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 487                                         $object_data['reply-to-id'] = $object_data['object_id'];
 488                                         ActivityPub\Processor::createActivity($object_data, Activity::FOLLOW);
 489                                 }
 490                                 break;
 491
 492                         case 'as:Accept':
 493                                 if ($object_data['object_type'] == 'as:Follow') {
 494                                         ActivityPub\Processor::acceptFollowUser($object_data);
 495                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 496                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTEND);
 497                                 }
 498                                 break;
 499
 500                         case 'as:Reject':
 501                                 if ($object_data['object_type'] == 'as:Follow') {
 502                                         ActivityPub\Processor::rejectFollowUser($object_data);
 503                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 504                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDNO);
 505                                 }
 506                                 break;
 507
 508                         case 'as:Undo':
 509                                 if (($object_data['object_type'] == 'as:Follow') &&
 510                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 511                                         ActivityPub\Processor::undoFollowUser($object_data);
 512                                 } elseif (($object_data['object_type'] == 'as:Accept') &&
 513                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 514                                         ActivityPub\Processor::rejectFollowUser($object_data);
 515                                 } elseif (in_array($object_data['object_type'], self::ACTIVITY_TYPES) &&
 516                                         in_array($object_data['object_object_type'], self::CONTENT_TYPES)) {
 517                                         ActivityPub\Processor::undoActivity($object_data);
 518                                 }
 519                                 break;
 520
 521                         default:
 522                                 Logger::log('Unknown activity: ' . $type . ' ' . $object_data['object_type'], Logger::DEBUG);
 523                                 break;
 524                 }
 525         }
 526
 527         /**
 528          * Fetch the receiver list from an activity array
 529          *
 530          * @param array   $activity
 531          * @param string  $actor
 532          * @param array   $tags
 533          * @param boolean $fetch_unlisted
 534          *
 535          * @return array with receivers (user id)
 536          * @throws \Exception
 537          */
 538         private static function getReceivers($activity, $actor, $tags = [], $fetch_unlisted = false)
 539         {
 540                 $receivers = [];
 541
 542                 // When it is an answer, we inherite the receivers from the parent
 543                 $replyto = JsonLD::fetchElement($activity, 'as:inReplyTo', '@id');
 544                 if (!empty($replyto)) {
 545                         // Fix possibly wrong item URI (could be an answer to a plink uri)
 546                         $fixedReplyTo = Item::getURIByLink($replyto);
 547                         $replyto = $fixedReplyTo ?: $replyto;
 548
 549                         $parents = Item::select(['uid'], ['uri' => $replyto]);
 550                         while ($parent = Item::fetch($parents)) {
 551                                 $receivers['uid:' . $parent['uid']] = $parent['uid'];
 552                         }
 553                 }
 554
 555                 if (!empty($actor)) {
 556                         $profile = APContact::getByURL($actor);
 557                         $followers = $profile['followers'] ?? '';
 558
 559                         Logger::log('Actor: ' . $actor . ' - Followers: ' . $followers, Logger::DEBUG);
 560                 } else {
 561                         Logger::info('Empty actor', ['activity' => $activity]);
 562                         $followers = '';
 563                 }
 564
 565                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
 566                         $receiver_list = JsonLD::fetchElementArray($activity, $element, '@id');
 567                         if (empty($receiver_list)) {
 568                                 continue;
 569                         }
 570
 571                         foreach ($receiver_list as $receiver) {
 572                                 if ($receiver == self::PUBLIC_COLLECTION) {
 573                                         $receivers['uid:0'] = 0;
 574                                 }
 575
 576                                 // Add receiver "-1" for unlisted posts
 577                                 if ($fetch_unlisted && ($receiver == self::PUBLIC_COLLECTION) && ($element == 'as:cc')) {
 578                                         $receivers['uid:-1'] = -1;
 579                                 }
 580
 581                                 // Fetch the receivers for the public and the followers collection
 582                                 if (in_array($receiver, [$followers, self::PUBLIC_COLLECTION]) && !empty($actor)) {
 583                                         $receivers = array_merge($receivers, self::getReceiverForActor($actor, $tags));
 584                                         continue;
 585                                 }
 586
 587                                 // Fetching all directly addressed receivers
 588                                 $condition = ['self' => true, 'nurl' => Strings::normaliseLink($receiver)];
 589                                 $contact = DBA::selectFirst('contact', ['uid', 'contact-type'], $condition);
 590                                 if (!DBA::isResult($contact)) {
 591                                         continue;
 592                                 }
 593
 594                                 // Check if the potential receiver is following the actor
 595                                 // Exception: The receiver is targetted via "to" or this is a comment
 596                                 if ((($element != 'as:to') && empty($replyto)) || ($contact['contact-type'] == Contact::TYPE_COMMUNITY)) {
 597                                         $networks = Protocol::FEDERATED;
 598                                         $condition = ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
 599                                                 'network' => $networks, 'archive' => false, 'pending' => false, 'uid' => $contact['uid']];
 600
 601                                         // Forum posts are only accepted from forum contacts
 602                                         if ($contact['contact-type'] == Contact::TYPE_COMMUNITY) {
 603                                                 $condition['rel'] = [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER];
 604                                         }
 605
 606                                         if (!DBA::exists('contact', $condition)) {
 607                                                 continue;
 608                                         }
 609                                 }
 610
 611                                 $receivers['uid:' . $contact['uid']] = $contact['uid'];
 612                         }
 613                 }
 614
 615                 self::switchContacts($receivers, $actor);
 616
 617                 return $receivers;
 618         }
 619
 620         /**
 621          * Fetch the receiver list of a given actor
 622          *
 623          * @param string $actor
 624          * @param array  $tags
 625          *
 626          * @return array with receivers (user id)
 627          * @throws \Exception
 628          */
 629         private static function getReceiverForActor($actor, $tags)
 630         {
 631                 $receivers = [];
 632                 $basecondition = ['rel' => [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER],
 633                         'network' => Protocol::FEDERATED, 'archive' => false, 'pending' => false];
 634
 635                 $condition = DBA::mergeConditions($basecondition, ['nurl' => Strings::normaliseLink($actor)]);
 636                 $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
 637                 while ($contact = DBA::fetch($contacts)) {
 638                         if (self::isValidReceiverForActor($contact, $actor, $tags)) {
 639                                 $receivers['uid:' . $contact['uid']] = $contact['uid'];
 640                         }
 641                 }
 642                 DBA::close($contacts);
 643
 644                 // The queries are split because of performance issues
 645                 $condition = DBA::mergeConditions($basecondition, ["`alias` IN (?, ?)", Strings::normaliseLink($actor), $actor]);
 646                 $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
 647                 while ($contact = DBA::fetch($contacts)) {
 648                         if (self::isValidReceiverForActor($contact, $actor, $tags)) {
 649                                 $receivers['uid:' . $contact['uid']] = $contact['uid'];
 650                         }
 651                 }
 652                 DBA::close($contacts);
 653                 return $receivers;
 654         }
 655
 656         /**
 657          * Tests if the contact is a valid receiver for this actor
 658          *
 659          * @param array  $contact
 660          * @param string $actor
 661          * @param array  $tags
 662          *
 663          * @return bool with receivers (user id)
 664          * @throws \Exception
 665          */
 666         private static function isValidReceiverForActor($contact, $actor, $tags)
 667         {
 668                 // Public contacts are no valid receiver
 669                 if ($contact['uid'] == 0) {
 670                         return false;
 671                 }
 672
 673                 // Are we following the contact? Then this is a valid receiver
 674                 if (in_array($contact['rel'], [Contact::SHARING, Contact::FRIEND])) {
 675                         return true;
 676                 }
 677
 678                 // When the possible receiver isn't a community, then it is no valid receiver
 679                 $owner = User::getOwnerDataById($contact['uid']);
 680                 if (empty($owner) || ($owner['contact-type'] != Contact::TYPE_COMMUNITY)) {
 681                         return false;
 682                 }
 683
 684                 // Is the community account tagged?
 685                 foreach ($tags as $tag) {
 686                         if ($tag['type'] != 'Mention') {
 687                                 continue;
 688                         }
 689
 690                         if ($tag['href'] == $owner['url']) {
 691                                 return true;
 692                         }
 693                 }
 694
 695                 return false;
 696         }
 697
 698         /**
 699          * Switches existing contacts to ActivityPub
 700          *
 701          * @param integer $cid Contact ID
 702          * @param integer $uid User ID
 703          * @param string  $url Profile URL
 704          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 705          * @throws \ImagickException
 706          */
 707         public static function switchContact($cid, $uid, $url)
 708         {
 709                 if (DBA::exists('contact', ['id' => $cid, 'network' => Protocol::ACTIVITYPUB])) {
 710                         Logger::info('Contact is already ActivityPub', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
 711                         return;
 712                 }
 713
 714                 if (Contact::updateFromProbe($cid)) {
 715                         Logger::info('Update was successful', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
 716                 }
 717
 718                 // Send a new follow request to be sure that the connection still exists
 719                 if (($uid != 0) && DBA::exists('contact', ['id' => $cid, 'rel' => [Contact::SHARING, Contact::FRIEND], 'network' => Protocol::ACTIVITYPUB])) {
 720                         Logger::info('Contact had been switched to ActivityPub. Sending a new follow request.', ['uid' => $uid, 'url' => $url]);
 721                         ActivityPub\Transmitter::sendActivity('Follow', $url, $uid);
 722                 }
 723         }
 724
 725         /**
 726          *
 727          *
 728          * @param $receivers
 729          * @param $actor
 730          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 731          * @throws \ImagickException
 732          */
 733         private static function switchContacts($receivers, $actor)
 734         {
 735                 if (empty($actor)) {
 736                         return;
 737                 }
 738
 739                 foreach ($receivers as $receiver) {
 740                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver, 'network' => Protocol::OSTATUS, 'nurl' => Strings::normaliseLink($actor)]);
 741                         if (DBA::isResult($contact)) {
 742                                 self::switchContact($contact['id'], $receiver, $actor);
 743                         }
 744
 745                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver, 'network' => Protocol::OSTATUS, 'alias' => [Strings::normaliseLink($actor), $actor]]);
 746                         if (DBA::isResult($contact)) {
 747                                 self::switchContact($contact['id'], $receiver, $actor);
 748                         }
 749                 }
 750         }
 751
 752         /**
 753          *
 754          *
 755          * @param       $object_data
 756          * @param array $activity
 757          *
 758          * @return mixed
 759          */
 760         private static function addActivityFields($object_data, $activity)
 761         {
 762                 if (!empty($activity['published']) && empty($object_data['published'])) {
 763                         $object_data['published'] = JsonLD::fetchElement($activity, 'as:published', '@value');
 764                 }
 765
 766                 if (!empty($activity['diaspora:guid']) && empty($object_data['diaspora:guid'])) {
 767                         $object_data['diaspora:guid'] = JsonLD::fetchElement($activity, 'diaspora:guid', '@value');
 768                 }
 769
 770                 $object_data['service'] = JsonLD::fetchElement($activity, 'as:instrument', 'as:name', '@type', 'as:Service');
 771                 $object_data['service'] = JsonLD::fetchElement($object_data, 'service', '@value');
 772
 773                 if (!empty($object_data['object_id'])) {
 774                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
 775                         $objectId = Item::getURIByLink($object_data['object_id']);
 776                         if (!empty($objectId) && ($object_data['object_id'] != $objectId)) {
 777                                 Logger::notice('Fix wrong object-id', ['received' => $object_data['object_id'], 'correct' => $objectId]);
 778                                 $object_data['object_id'] = $objectId;
 779                         }
 780                 }
 781
 782                 return $object_data;
 783         }
 784
 785         /**
 786          * Fetches the object data from external ressources if needed
 787          *
 788          * @param string  $object_id    Object ID of the the provided object
 789          * @param array   $object       The provided object array
 790          * @param boolean $trust_source Do we trust the provided object?
 791          * @param integer $uid          User ID for the signature that we use to fetch data
 792          *
 793          * @return array|false with trusted and valid object data
 794          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 795          * @throws \ImagickException
 796          */
 797         private static function fetchObject(string $object_id, array $object = [], bool $trust_source = false, int $uid = 0)
 798         {
 799                 // By fetching the type we check if the object is complete.
 800                 $type = JsonLD::fetchElement($object, '@type');
 801
 802                 if (!$trust_source || empty($type)) {
 803                         $data = ActivityPub::fetchContent($object_id, $uid);
 804                         if (!empty($data)) {
 805                                 $object = JsonLD::compact($data);
 806                                 Logger::log('Fetched content for ' . $object_id, Logger::DEBUG);
 807                         } else {
 808                                 Logger::log('Empty content for ' . $object_id . ', check if content is available locally.', Logger::DEBUG);
 809
 810                                 $item = Item::selectFirst([], ['uri' => $object_id]);
 811                                 if (!DBA::isResult($item)) {
 812                                         Logger::log('Object with url ' . $object_id . ' was not found locally.', Logger::DEBUG);
 813                                         return false;
 814                                 }
 815                                 Logger::log('Using already stored item for url ' . $object_id, Logger::DEBUG);
 816                                 $data = ActivityPub\Transmitter::createNote($item);
 817                                 $object = JsonLD::compact($data);
 818                         }
 819
 820                         $id = JsonLD::fetchElement($object, '@id');
 821                         if (empty($id)) {
 822                                 Logger::info('Empty id');
 823                                 return false;
 824                         }
 825
 826                         if ($id != $object_id) {
 827                                 Logger::info('Fetched id differs from provided id', ['provided' => $object_id, 'fetched' => $id]);
 828                                 return false;
 829                         }
 830                 } else {
 831                         Logger::log('Using original object for url ' . $object_id, Logger::DEBUG);
 832                 }
 833
 834                 $type = JsonLD::fetchElement($object, '@type');
 835                 if (empty($type)) {
 836                         Logger::info('Empty type');
 837                         return false;
 838                 }
 839
 840                 // We currently don't handle 'pt:CacheFile', but with this step we avoid logging
 841                 if (in_array($type, self::CONTENT_TYPES) || ($type == 'pt:CacheFile')) {
 842                         $object_data = self::processObject($object);
 843
 844                         if (!empty($data)) {
 845                                 $object_data['raw'] = json_encode($data);
 846                         }
 847                         return $object_data;
 848                 }
 849
 850                 if ($type == 'as:Announce') {
 851                         $object_id = JsonLD::fetchElement($object, 'object', '@id');
 852                         if (empty($object_id) || !is_string($object_id)) {
 853                                 return false;
 854                         }
 855                         return self::fetchObject($object_id, [], false, $uid);
 856                 }
 857
 858                 Logger::log('Unhandled object type: ' . $type, Logger::DEBUG);
 859                 return false;
 860         }
 861
 862         /**
 863          * Convert tags from JSON-LD format into a simplified format
 864          *
 865          * @param array $tags Tags in JSON-LD format
 866          *
 867          * @return array with tags in a simplified format
 868          */
 869         private static function processTags(array $tags)
 870         {
 871                 $taglist = [];
 872
 873                 foreach ($tags as $tag) {
 874                         if (empty($tag)) {
 875                                 continue;
 876                         }
 877
 878                         $element = ['type' => str_replace('as:', '', JsonLD::fetchElement($tag, '@type')),
 879                                 'href' => JsonLD::fetchElement($tag, 'as:href', '@id'),
 880                                 'name' => JsonLD::fetchElement($tag, 'as:name', '@value')];
 881
 882                         if (empty($element['type'])) {
 883                                 continue;
 884                         }
 885
 886                         if (empty($element['href'])) {
 887                                 $element['href'] = $element['name'];
 888                         }
 889
 890                         $taglist[] = $element;
 891                 }
 892                 return $taglist;
 893         }
 894
 895         /**
 896          * Convert emojis from JSON-LD format into a simplified format
 897          *
 898          * @param array $emojis
 899          * @return array with emojis in a simplified format
 900          */
 901         private static function processEmojis(array $emojis)
 902         {
 903                 $emojilist = [];
 904
 905                 foreach ($emojis as $emoji) {
 906                         if (empty($emoji) || (JsonLD::fetchElement($emoji, '@type') != 'toot:Emoji') || empty($emoji['as:icon'])) {
 907                                 continue;
 908                         }
 909
 910                         $url = JsonLD::fetchElement($emoji['as:icon'], 'as:url', '@id');
 911                         $element = ['name' => JsonLD::fetchElement($emoji, 'as:name', '@value'),
 912                                 'href' => $url];
 913
 914                         $emojilist[] = $element;
 915                 }
 916
 917                 return $emojilist;
 918         }
 919
 920         /**
 921          * Convert attachments from JSON-LD format into a simplified format
 922          *
 923          * @param array $attachments Attachments in JSON-LD format
 924          *
 925          * @return array Attachments in a simplified format
 926          */
 927         private static function processAttachments(array $attachments)
 928         {
 929                 $attachlist = [];
 930
 931                 // Removes empty values
 932                 $attachments = array_filter($attachments);
 933
 934                 foreach ($attachments as $attachment) {
 935                         switch (JsonLD::fetchElement($attachment, '@type')) {
 936                                 case 'as:Page':
 937                                         $pageUrl = null;
 938                                         $pageImage = null;
 939
 940                                         $urls = JsonLD::fetchElementArray($attachment, 'as:url');
 941                                         foreach ($urls as $url) {
 942                                                 // Single scalar URL case
 943                                                 if (is_string($url)) {
 944                                                         $pageUrl = $url;
 945                                                         continue;
 946                                                 }
 947
 948                                                 $href = JsonLD::fetchElement($url, 'as:href', '@id');
 949                                                 $mediaType = JsonLD::fetchElement($url, 'as:mediaType', '@value');
 950                                                 if (Strings::startsWith($mediaType, 'image')) {
 951                                                         $pageImage = $href;
 952                                                 } else {
 953                                                         $pageUrl = $href;
 954                                                 }
 955                                         }
 956
 957                                         $attachlist[] = [
 958                                                 'type'  => 'link',
 959                                                 'title' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
 960                                                 'desc'  => JsonLD::fetchElement($attachment, 'as:summary', '@value'),
 961                                                 'url'   => $pageUrl,
 962                                                 'image' => $pageImage,
 963                                         ];
 964                                         break;
 965                                 case 'as:Link':
 966                                         $attachlist[] = [
 967                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
 968                                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType', '@value'),
 969                                                 'name' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
 970                                                 'url' => JsonLD::fetchElement($attachment, 'as:href', '@id')
 971                                         ];
 972                                         break;
 973                                 case 'as:Image':
 974                                         $mediaType = JsonLD::fetchElement($attachment, 'as:mediaType', '@value');
 975                                         $imageFullUrl = JsonLD::fetchElement($attachment, 'as:url', '@id');
 976                                         $imagePreviewUrl = null;
 977                                         // Multiple URLs?
 978                                         if (!$imageFullUrl && ($urls = JsonLD::fetchElementArray($attachment, 'as:url'))) {
 979                                                 $imageVariants = [];
 980                                                 $previewVariants = [];
 981                                                 foreach ($urls as $url) {
 982                                                         // Scalar URL, no discrimination possible
 983                                                         if (is_string($url)) {
 984                                                                 $imageFullUrl = $url;
 985                                                                 continue;
 986                                                         }
 987
 988                                                         // Not sure what to do with a different Link media type than the base Image, we skip
 989                                                         if ($mediaType != JsonLD::fetchElement($url, 'as:mediaType', '@value')) {
 990                                                                 continue;
 991                                                         }
 992
 993                                                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
 994
 995                                                         // Default URL choice if no discriminating width is provided
 996                                                         $imageFullUrl = $href ?? $imageFullUrl;
 997
 998                                                         $width = intval(JsonLD::fetchElement($url, 'as:width', '@value') ?? 1);
 999
1000                                                         if ($href && $width) {
1001                                                                 $imageVariants[$width] = $href;
1002                                                                 // 632 is the ideal width for full screen frio posts, we compute the absolute distance to it
1003                                                                 $previewVariants[abs(632 - $width)] = $href;
1004                                                         }
1005                                                 }
1006
1007                                                 if ($imageVariants) {
1008                                                         // Taking the maximum size image
1009                                                         ksort($imageVariants);
1010                                                         $imageFullUrl = array_pop($imageVariants);
1011
1012                                                         // Taking the minimum number distance to the target distance
1013                                                         ksort($previewVariants);
1014                                                         $imagePreviewUrl = array_shift($previewVariants);
1015                                                 }
1016
1017                                                 unset($imageVariants);
1018                                                 unset($previewVariants);
1019                                         }
1020
1021                                         $attachlist[] = [
1022                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1023                                                 'mediaType' => $mediaType,
1024                                                 'name'  => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1025                                                 'url'   => $imageFullUrl,
1026                                                 'image' => $imagePreviewUrl !== $imageFullUrl ? $imagePreviewUrl : null,
1027                                         ];
1028                                         break;
1029                                 default:
1030                                         $attachlist[] = [
1031                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1032                                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType', '@value'),
1033                                                 'name' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1034                                                 'url' => JsonLD::fetchElement($attachment, 'as:url', '@id')
1035                                         ];
1036                         }
1037                 }
1038
1039                 return $attachlist;
1040         }
1041
1042         /**
1043          * Fetch the original source or content with the "language" Markdown or HTML
1044          *
1045          * @param array $object
1046          * @param array $object_data
1047          *
1048          * @return array
1049          * @throws \Exception
1050          */
1051         private static function getSource($object, $object_data)
1052         {
1053                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/bbcode');
1054                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1055                 if (!empty($object_data['source'])) {
1056                         return $object_data;
1057                 }
1058
1059                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/markdown');
1060                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1061                 if (!empty($object_data['source'])) {
1062                         $object_data['source'] = Markdown::toBBCode($object_data['source']);
1063                         return $object_data;
1064                 }
1065
1066                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/html');
1067                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1068                 if (!empty($object_data['source'])) {
1069                         $object_data['source'] = HTML::toBBCode($object_data['source']);
1070                         return $object_data;
1071                 }
1072
1073                 return $object_data;
1074         }
1075
1076         /**
1077          * Check if the "as:url" element is an array with multiple links
1078          * This is the case with audio and video posts.
1079          * Then the links are added as attachments
1080          *
1081          * @param array $object      The raw object
1082          * @param array $object_data The parsed object data for later processing
1083          * @return array the object data
1084          */
1085         private static function processAttachmentUrls(array $object, array $object_data) {
1086                 // Check if this is some url with multiple links
1087                 if (empty($object['as:url'])) {
1088                         return $object_data;
1089                 }
1090
1091                 $urls = $object['as:url'];
1092                 $keys = array_keys($urls);
1093                 if (!is_numeric(array_pop($keys))) {
1094                         return $object_data;
1095                 }
1096
1097                 $attachments = [];
1098
1099                 foreach ($urls as $url) {
1100                         if (empty($url['@type']) || ($url['@type'] != 'as:Link')) {
1101                                 continue;
1102                         }
1103
1104                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1105                         if (empty($href)) {
1106                                 continue;
1107                         }
1108
1109                         $mediatype = JsonLD::fetchElement($url, 'as:mediaType');
1110                         if (empty($mediatype)) {
1111                                 continue;
1112                         }
1113
1114                         if ($mediatype == 'text/html') {
1115                                 $object_data['alternate-url'] = $href;
1116                         }
1117
1118                         $filetype = strtolower(substr($mediatype, 0, strpos($mediatype, '/')));
1119
1120                         if ($filetype == 'audio') {
1121                                 $attachments[$filetype] = ['type' => $mediatype, 'url' => $href];
1122                         } elseif ($filetype == 'video') {
1123                                 $height = (int)JsonLD::fetchElement($url, 'as:height', '@value');
1124
1125                                 // We save bandwidth by using a moderate height
1126                                 // Peertube normally uses these heights: 240, 360, 480, 720, 1080
1127                                 if (!empty($attachments[$filetype]['height']) &&
1128                                         (($height > 480) || $height < $attachments[$filetype]['height'])) {
1129                                         continue;
1130                                 }
1131
1132                                 $attachments[$filetype] = ['type' => $mediatype, 'url' => $href, 'height' => $height];
1133                         }
1134                 }
1135
1136                 foreach ($attachments as $type => $attachment) {
1137                         $object_data['attachments'][] = ['type' => $type,
1138                                 'mediaType' => $attachment['type'],
1139                                 'name' => '',
1140                                 'url' => $attachment['url']];
1141                 }
1142                 return $object_data;
1143         }
1144
1145         /**
1146          * Fetches data from the object part of an activity
1147          *
1148          * @param array $object
1149          *
1150          * @return array
1151          * @throws \Exception
1152          */
1153         private static function processObject($object)
1154         {
1155                 if (!JsonLD::fetchElement($object, '@id')) {
1156                         return false;
1157                 }
1158
1159                 $object_data = [];
1160                 $object_data['object_type'] = JsonLD::fetchElement($object, '@type');
1161                 $object_data['id'] = JsonLD::fetchElement($object, '@id');
1162                 $object_data['reply-to-id'] = JsonLD::fetchElement($object, 'as:inReplyTo', '@id');
1163
1164                 // An empty "id" field is translated to "./" by the compactor, so we have to check for this content
1165                 if (empty($object_data['reply-to-id']) || ($object_data['reply-to-id'] == './')) {
1166                         $object_data['reply-to-id'] = $object_data['id'];
1167                 } else {
1168                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
1169                         $replyToId = Item::getURIByLink($object_data['reply-to-id']);
1170                         if (!empty($replyToId) && ($object_data['reply-to-id'] != $replyToId)) {
1171                                 Logger::notice('Fix wrong reply-to', ['received' => $object_data['reply-to-id'], 'correct' => $replyToId]);
1172                                 $object_data['reply-to-id'] = $replyToId;
1173                         }
1174                 }
1175
1176                 $object_data['published'] = JsonLD::fetchElement($object, 'as:published', '@value');
1177                 $object_data['updated'] = JsonLD::fetchElement($object, 'as:updated', '@value');
1178
1179                 if (empty($object_data['updated'])) {
1180                         $object_data['updated'] = $object_data['published'];
1181                 }
1182
1183                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
1184                         $object_data['published'] = $object_data['updated'];
1185                 }
1186
1187                 $actor = JsonLD::fetchElement($object, 'as:attributedTo', '@id');
1188                 if (empty($actor)) {
1189                         $actor = JsonLD::fetchElement($object, 'as:actor', '@id');
1190                 }
1191
1192                 $location = JsonLD::fetchElement($object, 'as:location', 'as:name', '@type', 'as:Place');
1193                 $location = JsonLD::fetchElement($location, 'location', '@value');
1194                 if ($location) {
1195                         // Some AP software allow formatted text in post location, so we run all the text converters we have to boil
1196                         // down to HTML and then finally format to plaintext.
1197                         $location = Markdown::convert($location);
1198                         $location = BBCode::convert($location);
1199                         $location = HTML::toPlaintext($location);
1200                 }
1201
1202                 $object_data['sc:identifier'] = JsonLD::fetchElement($object, 'sc:identifier', '@value');
1203                 $object_data['diaspora:guid'] = JsonLD::fetchElement($object, 'diaspora:guid', '@value');
1204                 $object_data['diaspora:comment'] = JsonLD::fetchElement($object, 'diaspora:comment', '@value');
1205                 $object_data['diaspora:like'] = JsonLD::fetchElement($object, 'diaspora:like', '@value');
1206                 $object_data['actor'] = $object_data['author'] = $actor;
1207                 $object_data['context'] = JsonLD::fetchElement($object, 'as:context', '@id');
1208                 $object_data['conversation'] = JsonLD::fetchElement($object, 'ostatus:conversation', '@id');
1209                 $object_data['sensitive'] = JsonLD::fetchElement($object, 'as:sensitive');
1210                 $object_data['name'] = JsonLD::fetchElement($object, 'as:name', '@value');
1211                 $object_data['summary'] = JsonLD::fetchElement($object, 'as:summary', '@value');
1212                 $object_data['content'] = JsonLD::fetchElement($object, 'as:content', '@value');
1213                 $object_data = self::getSource($object, $object_data);
1214                 $object_data['start-time'] = JsonLD::fetchElement($object, 'as:startTime', '@value');
1215                 $object_data['end-time'] = JsonLD::fetchElement($object, 'as:endTime', '@value');
1216                 $object_data['location'] = $location;
1217                 $object_data['latitude'] = JsonLD::fetchElement($object, 'as:location', 'as:latitude', '@type', 'as:Place');
1218                 $object_data['latitude'] = JsonLD::fetchElement($object_data, 'latitude', '@value');
1219                 $object_data['longitude'] = JsonLD::fetchElement($object, 'as:location', 'as:longitude', '@type', 'as:Place');
1220                 $object_data['longitude'] = JsonLD::fetchElement($object_data, 'longitude', '@value');
1221                 $object_data['attachments'] = self::processAttachments(JsonLD::fetchElementArray($object, 'as:attachment') ?? []);
1222                 $object_data['tags'] = self::processTags(JsonLD::fetchElementArray($object, 'as:tag') ?? []);
1223                 $object_data['emojis'] = self::processEmojis(JsonLD::fetchElementArray($object, 'as:tag', 'toot:Emoji') ?? []);
1224                 $object_data['generator'] = JsonLD::fetchElement($object, 'as:generator', 'as:name', '@type', 'as:Application');
1225                 $object_data['generator'] = JsonLD::fetchElement($object_data, 'generator', '@value');
1226                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'as:url', '@id');
1227
1228                 // Special treatment for Hubzilla links
1229                 if (is_array($object_data['alternate-url'])) {
1230                         $object_data['alternate-url'] = JsonLD::fetchElement($object_data['alternate-url'], 'as:href', '@id');
1231
1232                         if (!is_string($object_data['alternate-url'])) {
1233                                 $object_data['alternate-url'] = JsonLD::fetchElement($object['as:url'], 'as:href', '@id');
1234                         }
1235                 }
1236
1237                 if (in_array($object_data['object_type'], ['as:Audio', 'as:Video'])) {
1238                         $object_data = self::processAttachmentUrls($object, $object_data);
1239                 }
1240
1241                 $object_data['receiver'] = self::getReceivers($object, $object_data['actor'], $object_data['tags'], true);
1242                 $object_data['unlisted'] = in_array(-1, $object_data['receiver']);
1243                 unset($object_data['receiver']['uid:-1']);
1244
1245                 // Common object data:
1246
1247                 // Unhandled
1248                 // @context, type, actor, signature, mediaType, duration, replies, icon
1249
1250                 // Also missing: (Defined in the standard, but currently unused)
1251                 // audience, preview, endTime, startTime, image
1252
1253                 // Data in Notes:
1254
1255                 // Unhandled
1256                 // contentMap, announcement_count, announcements, context_id, likes, like_count
1257                 // inReplyToStatusId, shares, quoteUrl, statusnetConversationId
1258
1259                 // Data in video:
1260
1261                 // To-Do?
1262                 // category, licence, language, commentsEnabled
1263
1264                 // Unhandled
1265                 // views, waitTranscoding, state, support, subtitleLanguage
1266                 // likes, dislikes, shares, comments
1267
1268                 return $object_data;
1269         }
1270 }