src/Protocol/ActivityPub/Receiver.php

   1 <?php
   2 /**
   3  * @file src/Protocol/ActivityPub/Receiver.php
   4  */
   5 namespace Friendica\Protocol\ActivityPub;
   6
   7 use Friendica\Database\DBA;
   8 use Friendica\Util\HTTPSignature;
   9 use Friendica\Core\Protocol;
  10 use Friendica\Model\Contact;
  11 use Friendica\Model\APContact;
  12 use Friendica\Model\Item;
  13 use Friendica\Model\User;
  14 use Friendica\Util\JsonLD;
  15 use Friendica\Util\LDSignature;
  16 use Friendica\Protocol\ActivityPub;
  17
  18 /**
  19  * @brief ActivityPub Receiver Protocol class
  20  *
  21  * To-Do:
  22  * - Update (Image, Video, Article, Note)
  23  * - Event
  24  * - Undo Announce
  25  *
  26  * Check what this is meant to do:
  27  * - Add
  28  * - Block
  29  * - Flag
  30  * - Remove
  31  * - Undo Block
  32  * - Undo Accept (Problem: This could invert a contact accept or an event accept)
  33  *
  34  * General:
  35  * - Possibly using the LD-JSON parser
  36  */
  37 class Receiver
  38 {
  39         const PUBLIC_COLLECTION = 'as:Public';
  40         const ACCOUNT_TYPES = ['as:Person', 'as:Organization', 'as:Service', 'as:Group', 'as:Application'];
  41         const CONTENT_TYPES = ['as:Note', 'as:Article', 'as:Video', 'as:Image'];
  42         const ACTIVITY_TYPES = ['as:Like', 'as:Dislike', 'as:Accept', 'as:Reject', 'as:TentativeAccept'];
  43
  44         /**
  45          * Checks if the web request is done for the AP protocol
  46          *
  47          * @return is it AP?
  48          */
  49         public static function isRequest()
  50         {
  51                 return stristr(defaults($_SERVER, 'HTTP_ACCEPT', ''), 'application/activity+json') ||
  52                         stristr(defaults($_SERVER, 'HTTP_ACCEPT', ''), 'application/ld+json');
  53         }
  54
  55         /**
  56          * Checks incoming message from the inbox
  57          *
  58          * @param $body
  59          * @param $header
  60          * @param integer $uid User ID
  61          */
  62         public static function processInbox($body, $header, $uid)
  63         {
  64                 $http_signer = HTTPSignature::getSigner($body, $header);
  65                 if (empty($http_signer)) {
  66                         logger('Invalid HTTP signature, message will be discarded.', LOGGER_DEBUG);
  67                         return;
  68                 } else {
  69                         logger('HTTP signature is signed by ' . $http_signer, LOGGER_DEBUG);
  70                 }
  71
  72                 $activity = json_decode($body, true);
  73
  74                 if (empty($activity)) {
  75                         logger('Invalid body.', LOGGER_DEBUG);
  76                         return;
  77                 }
  78
  79                 $ldactivity = JsonLD::compact($activity);
  80
  81                 $actor = JsonLD::fetchElement($ldactivity, 'as:actor');
  82
  83                 logger('Message for user ' . $uid . ' is from actor ' . $actor, LOGGER_DEBUG);
  84
  85                 if (LDSignature::isSigned($activity)) {
  86                         $ld_signer = LDSignature::getSigner($activity);
  87                         if (empty($ld_signer)) {
  88                                 logger('Invalid JSON-LD signature from ' . $actor, LOGGER_DEBUG);
  89                         }
  90                         if (!empty($ld_signer && ($actor == $http_signer))) {
  91                                 logger('The HTTP and the JSON-LD signature belong to ' . $ld_signer, LOGGER_DEBUG);
  92                                 $trust_source = true;
  93                         } elseif (!empty($ld_signer)) {
  94                                 logger('JSON-LD signature is signed by ' . $ld_signer, LOGGER_DEBUG);
  95                                 $trust_source = true;
  96                         } elseif ($actor == $http_signer) {
  97                                 logger('Bad JSON-LD signature, but HTTP signer fits the actor.', LOGGER_DEBUG);
  98                                 $trust_source = true;
  99                         } else {
 100                                 logger('Invalid JSON-LD signature and the HTTP signer is different.', LOGGER_DEBUG);
 101                                 $trust_source = false;
 102                         }
 103                 } elseif ($actor == $http_signer) {
 104                         logger('Trusting post without JSON-LD signature, The actor fits the HTTP signer.', LOGGER_DEBUG);
 105                         $trust_source = true;
 106                 } else {
 107                         logger('No JSON-LD signature, different actor.', LOGGER_DEBUG);
 108                         $trust_source = false;
 109                 }
 110
 111                 self::processActivity($ldactivity, $body, $uid, $trust_source);
 112         }
 113
 114         /**
 115          *
 116          *
 117          * @param array $activity
 118          * @param integer $uid User ID
 119          * @param $trust_source
 120          *
 121          * @return
 122          */
 123         private static function prepareObjectData($ldactivity, $uid, &$trust_source)
 124         {
 125                 $actor = JsonLD::fetchElement($ldactivity, 'as:actor');
 126                 if (empty($actor)) {
 127                         logger('Empty actor', LOGGER_DEBUG);
 128                         return [];
 129                 }
 130
 131                 $type = JsonLD::fetchElement($ldactivity, '@type');
 132
 133                 // Fetch all receivers from to, cc, bto and bcc
 134                 $receivers = self::getReceivers($ldactivity, $actor);
 135
 136                 // When it is a delivery to a personal inbox we add that user to the receivers
 137                 if (!empty($uid)) {
 138                         $owner = User::getOwnerDataById($uid);
 139                         $additional = ['uid:' . $uid => $uid];
 140                         $receivers = array_merge($receivers, $additional);
 141                 }
 142
 143                 logger('Receivers: ' . json_encode($receivers), LOGGER_DEBUG);
 144
 145                 $object_id = JsonLD::fetchElement($ldactivity, 'as:object');
 146                 if (empty($object_id)) {
 147                         logger('No object found', LOGGER_DEBUG);
 148                         return [];
 149                 }
 150
 151                 // Fetch the content only on activities where this matters
 152                 if (in_array($type, ['as:Create', 'as:Announce'])) {
 153                         if ($type == 'as:Announce') {
 154                                 $trust_source = false;
 155                         }
 156                         $object_data = self::fetchObject($object_id, $ldactivity['as:object'], $trust_source);
 157                         if (empty($object_data)) {
 158                                 logger("Object data couldn't be processed", LOGGER_DEBUG);
 159                                 return [];
 160                         }
 161                         // We had been able to retrieve the object data - so we can trust the source
 162                         $trust_source = true;
 163                 } elseif (in_array($type, ['as:Like', 'as:Dislike'])) {
 164                         // Create a mostly empty array out of the activity data (instead of the object).
 165                         // This way we later don't have to check for the existence of ech individual array element.
 166                         $object_data = self::processObject($ldactivity);
 167                         $object_data['name'] = $type;
 168                         $object_data['author'] = JsonLD::fetchElement($ldactivity, 'as:actor');
 169                         $object_data['object'] = $object_id;
 170                         $object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
 171                 } else {
 172                         $object_data = [];
 173                         $object_data['id'] = JsonLD::fetchElement($ldactivity, '@id');
 174                         $object_data['object'] = $ldactivity['as:object'];
 175                         $object_data['object_type'] = JsonLD::fetchElement($ldactivity, 'as:object', '@type');
 176                 }
 177
 178                 $object_data = self::addActivityFields($object_data, $ldactivity);
 179
 180                 $object_data['type'] = $type;
 181                 $object_data['owner'] = $actor;
 182                 $object_data['receiver'] = array_merge(defaults($object_data, 'receiver', []), $receivers);
 183
 184                 logger('Processing ' . $object_data['type'] . ' ' . $object_data['object_type'] . ' ' . $object_data['id'], LOGGER_DEBUG);
 185
 186                 return $object_data;
 187         }
 188
 189         /**
 190          * Processes the activity object
 191          *
 192          * @param array   $activity     Array with activity data
 193          * @param string  $body
 194          * @param integer $uid          User ID
 195          * @param boolean $trust_source Do we trust the source?
 196          */
 197         public static function processActivity($ldactivity, $body = '', $uid = null, $trust_source = false)
 198         {
 199                 $type = JsonLD::fetchElement($ldactivity, '@type');
 200                 if (!$type) {
 201                         logger('Empty type', LOGGER_DEBUG);
 202                         return;
 203                 }
 204
 205                 if (!JsonLD::fetchElement($ldactivity, 'as:object')) {
 206                         logger('Empty object', LOGGER_DEBUG);
 207                         return;
 208                 }
 209
 210                 if (!JsonLD::fetchElement($ldactivity, 'as:actor')) {
 211                         logger('Empty actor', LOGGER_DEBUG);
 212                         return;
 213
 214                 }
 215
 216                 // $trust_source is called by reference and is set to true if the content was retrieved successfully
 217                 $object_data = self::prepareObjectData($ldactivity, $uid, $trust_source);
 218                 if (empty($object_data)) {
 219                         logger('No object data found', LOGGER_DEBUG);
 220                         return;
 221                 }
 222
 223                 if (!$trust_source) {
 224                         logger('No trust for activity type "' . $type . '", so we quit now.', LOGGER_DEBUG);
 225                         return;
 226                 }
 227
 228                 switch ($type) {
 229                         case 'as:Create':
 230                         case 'as:Announce':
 231                                 ActivityPub\Processor::createItem($object_data, $body);
 232                                 break;
 233
 234                         case 'as:Like':
 235                                 ActivityPub\Processor::likeItem($object_data, $body);
 236                                 break;
 237
 238                         case 'as:Dislike':
 239                                 ActivityPub\Processor::dislikeItem($object_data, $body);
 240                                 break;
 241
 242                         case 'as:Update':
 243                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 244                                         /// @todo
 245                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 246                                         ActivityPub\Processor::updatePerson($object_data, $body);
 247                                 }
 248                                 break;
 249
 250                         case 'as:Delete':
 251                                 if ($object_data['object_type'] == 'as:Tombstone') {
 252                                         ActivityPub\Processor::deleteItem($object_data, $body);
 253                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 254                                         ActivityPub\Processor::deletePerson($object_data, $body);
 255                                 }
 256                                 break;
 257
 258                         case 'as:Follow':
 259                                 ActivityPub\Processor::followUser($object_data);
 260                                 break;
 261
 262                         case 'as:Accept':
 263                                 if ($object_data['object_type'] == 'as:Follow') {
 264                                         ActivityPub\Processor::acceptFollowUser($object_data);
 265                                 }
 266                                 break;
 267
 268                         case 'as:Reject':
 269                                 if ($object_data['object_type'] == 'as:Follow') {
 270                                         ActivityPub\Processor::rejectFollowUser($object_data);
 271                                 }
 272                                 break;
 273
 274                         case 'as:Undo':
 275                                 if ($object_data['object_type'] == 'as:Follow') {
 276                                         ActivityPub\Processor::undoFollowUser($object_data);
 277                                 } elseif (in_array($object_data['object_type'], self::ACTIVITY_TYPES)) {
 278                                         ActivityPub\Processor::undoActivity($object_data);
 279                                 }
 280                                 break;
 281
 282                         default:
 283                                 logger('Unknown activity: ' . $type, LOGGER_DEBUG);
 284                                 break;
 285                 }
 286         }
 287
 288         /**
 289          * Fetch the receiver list from an activity array
 290          *
 291          * @param array $activity
 292          * @param string $actor
 293          *
 294          * @return array with receivers (user id)
 295          */
 296         private static function getReceivers($activity, $actor)
 297         {
 298                 $receivers = [];
 299
 300                 // When it is an answer, we inherite the receivers from the parent
 301                 $replyto = JsonLD::fetchElement($activity, 'as:inReplyTo');
 302                 if (!empty($replyto)) {
 303                         $parents = Item::select(['uid'], ['uri' => $replyto]);
 304                         while ($parent = Item::fetch($parents)) {
 305                                 $receivers['uid:' . $parent['uid']] = $parent['uid'];
 306                         }
 307                 }
 308
 309                 if (!empty($actor)) {
 310                         $profile = APContact::getByURL($actor);
 311                         $followers = defaults($profile, 'followers', '');
 312
 313                         logger('Actor: ' . $actor . ' - Followers: ' . $followers, LOGGER_DEBUG);
 314                 } else {
 315                         logger('Empty actor', LOGGER_DEBUG);
 316                         $followers = '';
 317                 }
 318
 319                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
 320                         $receiver_list = JsonLD::fetchElementArray($activity, $element);
 321                         if (empty($receiver_list)) {
 322                                 continue;
 323                         }
 324
 325                         foreach ($receiver_list as $receiver) {
 326                                 if ($receiver == self::PUBLIC_COLLECTION) {
 327                                         $receivers['uid:0'] = 0;
 328                                 }
 329
 330                                 if (($receiver == self::PUBLIC_COLLECTION) && !empty($actor)) {
 331                                         // This will most likely catch all OStatus connections to Mastodon
 332                                         $condition = ['alias' => [$actor, normalise_link($actor)], 'rel' => [Contact::SHARING, Contact::FRIEND]
 333                                                 , 'archive' => false, 'pending' => false];
 334                                         $contacts = DBA::select('contact', ['uid'], $condition);
 335                                         while ($contact = DBA::fetch($contacts)) {
 336                                                 if ($contact['uid'] != 0) {
 337                                                         $receivers['uid:' . $contact['uid']] = $contact['uid'];
 338                                                 }
 339                                         }
 340                                         DBA::close($contacts);
 341                                 }
 342
 343                                 if (in_array($receiver, [$followers, self::PUBLIC_COLLECTION]) && !empty($actor)) {
 344                                         $condition = ['nurl' => normalise_link($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
 345                                                 'network' => Protocol::ACTIVITYPUB, 'archive' => false, 'pending' => false];
 346                                         $contacts = DBA::select('contact', ['uid'], $condition);
 347                                         while ($contact = DBA::fetch($contacts)) {
 348                                                 if ($contact['uid'] != 0) {
 349                                                         $receivers['uid:' . $contact['uid']] = $contact['uid'];
 350                                                 }
 351                                         }
 352                                         DBA::close($contacts);
 353                                         continue;
 354                                 }
 355
 356                                 $condition = ['self' => true, 'nurl' => normalise_link($receiver)];
 357                                 $contact = DBA::selectFirst('contact', ['uid'], $condition);
 358                                 if (!DBA::isResult($contact)) {
 359                                         continue;
 360                                 }
 361                                 $receivers['uid:' . $contact['uid']] = $contact['uid'];
 362                         }
 363                 }
 364
 365                 self::switchContacts($receivers, $actor);
 366
 367                 return $receivers;
 368         }
 369
 370         /**
 371          * Switches existing contacts to ActivityPub
 372          *
 373          * @param integer $cid Contact ID
 374          * @param integer $uid User ID
 375          * @param string $url Profile URL
 376          */
 377         private static function switchContact($cid, $uid, $url)
 378         {
 379                 $profile = ActivityPub::probeProfile($url);
 380                 if (empty($profile)) {
 381                         return;
 382                 }
 383
 384                 logger('Switch contact ' . $cid . ' (' . $profile['url'] . ') for user ' . $uid . ' to ActivityPub');
 385
 386                 $photo = $profile['photo'];
 387                 unset($profile['photo']);
 388                 unset($profile['baseurl']);
 389
 390                 $profile['nurl'] = normalise_link($profile['url']);
 391                 DBA::update('contact', $profile, ['id' => $cid]);
 392
 393                 Contact::updateAvatar($photo, $uid, $cid);
 394
 395                 // Send a new follow request to be sure that the connection still exists
 396                 if (($uid != 0) && DBA::exists('contact', ['id' => $cid, 'rel' => [Contact::SHARING, Contact::FRIEND]])) {
 397                         ActivityPub\Transmitter::sendActivity('Follow', $profile['url'], $uid);
 398                         logger('Send a new follow request to ' . $profile['url'] . ' for user ' . $uid, LOGGER_DEBUG);
 399                 }
 400         }
 401
 402         /**
 403          *
 404          *
 405          * @param $receivers
 406          * @param $actor
 407          */
 408         private static function switchContacts($receivers, $actor)
 409         {
 410                 if (empty($actor)) {
 411                         return;
 412                 }
 413
 414                 foreach ($receivers as $receiver) {
 415                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver, 'network' => Protocol::OSTATUS, 'nurl' => normalise_link($actor)]);
 416                         if (DBA::isResult($contact)) {
 417                                 self::switchContact($contact['id'], $receiver, $actor);
 418                         }
 419
 420                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver, 'network' => Protocol::OSTATUS, 'alias' => [normalise_link($actor), $actor]]);
 421                         if (DBA::isResult($contact)) {
 422                                 self::switchContact($contact['id'], $receiver, $actor);
 423                         }
 424                 }
 425         }
 426
 427         /**
 428          *
 429          *
 430          * @param $object_data
 431          * @param array $activity
 432          *
 433          * @return
 434          */
 435         private static function addActivityFields($object_data, $activity)
 436         {
 437                 if (!empty($activity['published']) && empty($object_data['published'])) {
 438                         $object_data['published'] = JsonLD::fetchElement($activity, 'published', '@value');
 439                 }
 440
 441                 if (!empty($activity['updated']) && empty($object_data['updated'])) {
 442                         $object_data['updated'] = JsonLD::fetchElement($activity, 'updated', '@value');
 443                 }
 444
 445                 if (!empty($activity['diaspora:guid']) && empty($object_data['diaspora:guid'])) {
 446                         $object_data['diaspora:guid'] = JsonLD::fetchElement($activity, 'diaspora:guid');
 447                 }
 448
 449                 if (!empty($activity['inReplyTo']) && empty($object_data['parent-uri'])) {
 450                         $object_data['parent-uri'] = JsonLD::fetchElement($activity, 'inReplyTo');
 451                 }
 452
 453                 if (!empty($activity['instrument'])) {
 454                         $object_data['service'] = JsonLD::fetchElement($activity, 'instrument', 'name', 'type', 'Service');
 455                 }
 456                 return $object_data;
 457         }
 458
 459         /**
 460          * Fetches the object data from external ressources if needed
 461          *
 462          * @param string  $object_id    Object ID of the the provided object
 463          * @param array   $object       The provided object array
 464          * @param boolean $trust_source Do we trust the provided object?
 465          *
 466          * @return array with trusted and valid object data
 467          */
 468         private static function fetchObject($object_id, $object = [], $trust_source = false)
 469         {
 470                 // By fetching the type we check if the object is complete.
 471                 $type = JsonLD::fetchElement($object, '@type');
 472
 473                 if (!$trust_source || empty($type)) {
 474                         $data = ActivityPub::fetchContent($object_id);
 475                         if (!empty($data)) {
 476                                 $object = JsonLD::compact($data);
 477                                 logger('Fetched content for ' . $object_id, LOGGER_DEBUG);
 478                         } else {
 479                                 logger('Empty content for ' . $object_id . ', check if content is available locally.', LOGGER_DEBUG);
 480
 481                                 $item = Item::selectFirst([], ['uri' => $object_id]);
 482                                 if (!DBA::isResult($item)) {
 483                                         logger('Object with url ' . $object_id . ' was not found locally.', LOGGER_DEBUG);
 484                                         return false;
 485                                 }
 486                                 logger('Using already stored item for url ' . $object_id, LOGGER_DEBUG);
 487                                 $data = ActivityPub\Transmitter::createNote($item);
 488                                 $object = JsonLD::compact($data);
 489                         }
 490                 } else {
 491                         logger('Using original object for url ' . $object_id, LOGGER_DEBUG);
 492                 }
 493
 494                 $type = JsonLD::fetchElement($object, '@type');
 495
 496                 if (empty($type)) {
 497                         logger('Empty type', LOGGER_DEBUG);
 498                         return false;
 499                 }
 500
 501                 if (in_array($type, self::CONTENT_TYPES)) {
 502                         return self::processObject($object);
 503                 }
 504
 505                 if ($type == 'as:Announce') {
 506                         $object_id = JsonLD::fetchElement($object, 'object');
 507                         if (empty($object_id)) {
 508                                 return false;
 509                         }
 510                         return self::fetchObject($object_id);
 511                 }
 512
 513                 logger('Unhandled object type: ' . $type, LOGGER_DEBUG);
 514         }
 515
 516         /**
 517          * Convert tags from JSON-LD format into a simplified format
 518          *
 519          * @param array $tags Tags in JSON-LD format
 520          *
 521          * @return array with tags in a simplified format
 522          */
 523         private static function processTags($tags)
 524         {
 525                 $taglist = [];
 526
 527                 if (empty($tags)) {
 528                         return [];
 529                 }
 530
 531                 foreach ($tags as $tag) {
 532                         if (empty($tag)) {
 533                                 continue;
 534                         }
 535
 536                         $taglist[] = ['type' => str_replace('as:', '', JsonLD::fetchElement($tag, '@type')),
 537                                 'href' => JsonLD::fetchElement($tag, 'as:href'),
 538                                 'name' => JsonLD::fetchElement($tag, 'as:name')];
 539                 }
 540                 return $taglist;
 541         }
 542
 543         /**
 544          * Convert attachments from JSON-LD format into a simplified format
 545          *
 546          * @param array $attachments Attachments in JSON-LD format
 547          *
 548          * @return array with attachmants in a simplified format
 549          */
 550         private static function processAttachments($attachments)
 551         {
 552                 $attachlist = [];
 553
 554                 if (empty($attachments)) {
 555                         return [];
 556                 }
 557
 558                 foreach ($attachments as $attachment) {
 559                         if (empty($attachment)) {
 560                                 continue;
 561                         }
 562
 563                         $attachlist[] = ['type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
 564                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType'),
 565                                 'name' => JsonLD::fetchElement($attachment, 'as:name'),
 566                                 'url' => JsonLD::fetchElement($attachment, 'as:url')];
 567                 }
 568                 return $attachlist;
 569         }
 570
 571         /**
 572          * Fetches data from the object part of an activity
 573          *
 574          * @param array $object
 575          *
 576          * @return array
 577          */
 578         private static function processObject($object)
 579         {
 580                 if (!JsonLD::fetchElement($object, '@id')) {
 581                         return false;
 582                 }
 583
 584                 $object_data = [];
 585                 $object_data['object_type'] = JsonLD::fetchElement($object, '@type');
 586                 $object_data['id'] = JsonLD::fetchElement($object, '@id');
 587
 588                 $object_data['reply-to-id'] = JsonLD::fetchElement($object, 'as:inReplyTo');
 589
 590                 if (empty($object_data['reply-to-id'])) {
 591                         $object_data['reply-to-id'] = $object_data['id'];
 592                 }
 593
 594                 $object_data['published'] = JsonLD::fetchElement($object, 'as:published', '@value');
 595                 $object_data['updated'] = JsonLD::fetchElement($object, 'as:updated', '@value');
 596
 597                 if (empty($object_data['updated'])) {
 598                         $object_data['updated'] = $object_data['published'];
 599                 }
 600
 601                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
 602                         $object_data['published'] = $object_data['updated'];
 603                 }
 604
 605                 $actor = JsonLD::fetchElement($object, 'as:attributedTo');
 606                 if (empty($actor)) {
 607                         $actor = JsonLD::fetchElement($object, 'as:actor');
 608                 }
 609
 610                 $object_data['diaspora:guid'] = JsonLD::fetchElement($object, 'diaspora:guid');
 611                 $object_data['diaspora:comment'] = JsonLD::fetchElement($object, 'diaspora:comment');
 612                 $object_data['owner'] = $object_data['author'] = $actor;
 613                 $object_data['context'] = JsonLD::fetchElement($object, 'as:context');
 614                 $object_data['conversation'] = JsonLD::fetchElement($object, 'ostatus:conversation');
 615                 $object_data['sensitive'] = JsonLD::fetchElement($object, 'as:sensitive');
 616                 $object_data['name'] = JsonLD::fetchElement($object, 'as:name');
 617                 $object_data['summary'] = JsonLD::fetchElement($object, 'as:summary');
 618                 $object_data['content'] = JsonLD::fetchElement($object, 'as:content');
 619                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/bbcode');
 620                 $object_data['location'] = JsonLD::fetchElement($object, 'as:location', 'as:name', '@type', 'as:Place');
 621                 $object_data['attachments'] = self::processAttachments(JsonLD::fetchElementArray($object, 'as:attachment'));
 622                 $object_data['tags'] = self::processTags(JsonLD::fetchElementArray($object, 'as:tag'));
 623 //              $object_data['service'] = JsonLD::fetchElement($object, 'instrument', 'name', 'type', 'Service'); // todo
 624                 $object_data['service'] = null;
 625                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'as:url');
 626
 627                 // Special treatment for Hubzilla links
 628                 if (is_array($object_data['alternate-url'])) {
 629                         if (!empty($object['as:url'])) {
 630                                 $object_data['alternate-url'] = JsonLD::fetchElement($object['as:url'], 'as:href');
 631                         } else {
 632                                 $object_data['alternate-url'] = null;
 633                         }
 634                 }
 635
 636                 $object_data['receiver'] = self::getReceivers($object, $object_data['owner']);
 637
 638                 // Common object data:
 639
 640                 // Unhandled
 641                 // @context, type, actor, signature, mediaType, duration, replies, icon
 642
 643                 // Also missing: (Defined in the standard, but currently unused)
 644                 // audience, preview, endTime, startTime, generator, image
 645
 646                 // Data in Notes:
 647
 648                 // Unhandled
 649                 // contentMap, announcement_count, announcements, context_id, likes, like_count
 650                 // inReplyToStatusId, shares, quoteUrl, statusnetConversationId
 651
 652                 // Data in video:
 653
 654                 // To-Do?
 655                 // category, licence, language, commentsEnabled
 656
 657                 // Unhandled
 658                 // views, waitTranscoding, state, support, subtitleLanguage
 659                 // likes, dislikes, shares, comments
 660
 661                 return $object_data;
 662         }
 663 }