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 class Receiver
  35 {
  36         const PUBLIC_COLLECTION = 'as:Public';
  37         const ACCOUNT_TYPES = ['as:Person', 'as:Organization', 'as:Service', 'as:Group', 'as:Application'];
  38         const CONTENT_TYPES = ['as:Note', 'as:Article', 'as:Video', 'as:Image'];
  39         const ACTIVITY_TYPES = ['as:Like', 'as:Dislike', 'as:Accept', 'as:Reject', 'as:TentativeAccept'];
  40
  41         /**
  42          * Checks if the web request is done for the AP protocol
  43          *
  44          * @return is it AP?
  45          */
  46         public static function isRequest()
  47         {
  48                 return stristr(defaults($_SERVER, 'HTTP_ACCEPT', ''), 'application/activity+json') ||
  49                         stristr(defaults($_SERVER, 'HTTP_ACCEPT', ''), 'application/ld+json');
  50         }
  51
  52         /**
  53          * Checks incoming message from the inbox
  54          *
  55          * @param $body
  56          * @param $header
  57          * @param integer $uid User ID
  58          */
  59         public static function processInbox($body, $header, $uid)
  60         {
  61                 $http_signer = HTTPSignature::getSigner($body, $header);
  62                 if (empty($http_signer)) {
  63                         logger('Invalid HTTP signature, message will be discarded.', LOGGER_DEBUG);
  64                         return;
  65                 } else {
  66                         logger('HTTP signature is signed by ' . $http_signer, LOGGER_DEBUG);
  67                 }
  68
  69                 $activity = json_decode($body, true);
  70
  71                 if (empty($activity)) {
  72                         logger('Invalid body.', LOGGER_DEBUG);
  73                         return;
  74                 }
  75
  76                 $ldactivity = JsonLD::compact($activity);
  77
  78                 $actor = JsonLD::fetchElement($ldactivity, 'as:actor');
  79
  80                 logger('Message for user ' . $uid . ' is from actor ' . $actor, LOGGER_DEBUG);
  81
  82                 if (LDSignature::isSigned($activity)) {
  83                         $ld_signer = LDSignature::getSigner($activity);
  84                         if (empty($ld_signer)) {
  85                                 logger('Invalid JSON-LD signature from ' . $actor, LOGGER_DEBUG);
  86                         }
  87                         if (!empty($ld_signer && ($actor == $http_signer))) {
  88                                 logger('The HTTP and the JSON-LD signature belong to ' . $ld_signer, LOGGER_DEBUG);
  89                                 $trust_source = true;
  90                         } elseif (!empty($ld_signer)) {
  91                                 logger('JSON-LD signature is signed by ' . $ld_signer, LOGGER_DEBUG);
  92                                 $trust_source = true;
  93                         } elseif ($actor == $http_signer) {
  94                                 logger('Bad JSON-LD signature, but HTTP signer fits the actor.', LOGGER_DEBUG);
  95                                 $trust_source = true;
  96                         } else {
  97                                 logger('Invalid JSON-LD signature and the HTTP signer is different.', LOGGER_DEBUG);
  98                                 $trust_source = false;
  99                         }
 100                 } elseif ($actor == $http_signer) {
 101                         logger('Trusting post without JSON-LD signature, The actor fits the HTTP signer.', LOGGER_DEBUG);
 102                         $trust_source = true;
 103                 } else {
 104                         logger('No JSON-LD signature, different actor.', LOGGER_DEBUG);
 105                         $trust_source = false;
 106                 }
 107
 108                 self::processActivity($ldactivity, $body, $uid, $trust_source);
 109         }
 110
 111         /**
 112          * Fetches the object type for a given object id
 113          *
 114          * @param array  $activity
 115          * @param string $object_id Object ID of the the provided object
 116          *
 117          * @return string with object type
 118          */
 119         private static function fetchObjectType($activity, $object_id)
 120         {
 121
 122                 $object_type = JsonLD::fetchElement($activity['as:object'], '@type');
 123                 if (!empty($object_type)) {
 124                         return $object_type;
 125                 }
 126
 127                 if (Item::exists(['uri' => $object_id, 'gravity' => [GRAVITY_PARENT, GRAVITY_COMMENT]])) {
 128                         // We just assume "note" since it doesn't make a difference for the further processing
 129                         return 'as:Note';
 130                 }
 131
 132                 $profile = APContact::getByURL($object_id);
 133                 if (!empty($profile['type'])) {
 134                         return 'as:' . $profile['type'];
 135                 }
 136
 137                 $data = ActivityPub::fetchContent($object_id);
 138                 if (!empty($data)) {
 139                         $object = JsonLD::compact($data);
 140                         $type = JsonLD::fetchElement($object, '@type');
 141                         if (!empty($type)) {
 142                                 return $type;
 143                         }
 144                 }
 145
 146                 return null;
 147         }
 148
 149         /**
 150          * Prepare the object array
 151          *
 152          * @param array $activity
 153          * @param integer $uid User ID
 154          * @param $trust_source
 155          *
 156          * @return array with object data
 157          */
 158         private static function prepareObjectData($activity, $uid, &$trust_source)
 159         {
 160                 $actor = JsonLD::fetchElement($activity, 'as:actor');
 161                 if (empty($actor)) {
 162                         logger('Empty actor', LOGGER_DEBUG);
 163                         return [];
 164                 }
 165
 166                 $type = JsonLD::fetchElement($activity, '@type');
 167
 168                 // Fetch all receivers from to, cc, bto and bcc
 169                 $receivers = self::getReceivers($activity, $actor);
 170
 171                 // When it is a delivery to a personal inbox we add that user to the receivers
 172                 if (!empty($uid)) {
 173                         $owner = User::getOwnerDataById($uid);
 174                         $additional = ['uid:' . $uid => $uid];
 175                         $receivers = array_merge($receivers, $additional);
 176                 }
 177
 178                 logger('Receivers: ' . json_encode($receivers), LOGGER_DEBUG);
 179
 180                 $object_id = JsonLD::fetchElement($activity, 'as:object');
 181                 if (empty($object_id)) {
 182                         logger('No object found', LOGGER_DEBUG);
 183                         return [];
 184                 }
 185
 186                 $object_type = self::fetchObjectType($activity, $object_id);
 187
 188                 // Fetch the content only on activities where this matters
 189                 if (in_array($type, ['as:Create', 'as:Announce'])) {
 190                         if ($type == 'as:Announce') {
 191                                 $trust_source = false;
 192                         }
 193                         $object_data = self::fetchObject($object_id, $activity['as:object'], $trust_source);
 194                         if (empty($object_data)) {
 195                                 logger("Object data couldn't be processed", LOGGER_DEBUG);
 196                                 return [];
 197                         }
 198                         // We had been able to retrieve the object data - so we can trust the source
 199                         $trust_source = true;
 200                 } elseif (in_array($type, ['as:Like', 'as:Dislike'])) {
 201                         // Create a mostly empty array out of the activity data (instead of the object).
 202                         // This way we later don't have to check for the existence of ech individual array element.
 203                         $object_data = self::processObject($activity);
 204                         $object_data['name'] = $type;
 205                         $object_data['author'] = JsonLD::fetchElement($activity, 'as:actor');
 206                         $object_data['object_id'] = $object_id;
 207                         $object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
 208                 } else {
 209                         $object_data = [];
 210                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 211                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object');
 212                         $object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor');
 213                         $object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
 214                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 215                 }
 216
 217                 $object_data = self::addActivityFields($object_data, $activity);
 218
 219                 if (empty($object_data['object_type'])) {
 220                         $object_data['object_type'] = $object_type;
 221                 }
 222
 223                 $object_data['type'] = $type;
 224                 $object_data['actor'] = $actor;
 225                 $object_data['receiver'] = array_merge(defaults($object_data, 'receiver', []), $receivers);
 226
 227                 logger('Processing ' . $object_data['type'] . ' ' . $object_data['object_type'] . ' ' . $object_data['id'], LOGGER_DEBUG);
 228
 229                 return $object_data;
 230         }
 231
 232         /**
 233          * Processes the activity object
 234          *
 235          * @param array   $activity     Array with activity data
 236          * @param string  $body
 237          * @param integer $uid          User ID
 238          * @param boolean $trust_source Do we trust the source?
 239          */
 240         public static function processActivity($activity, $body = '', $uid = null, $trust_source = false)
 241         {
 242                 $type = JsonLD::fetchElement($activity, '@type');
 243                 if (!$type) {
 244                         logger('Empty type', LOGGER_DEBUG);
 245                         return;
 246                 }
 247
 248                 if (!JsonLD::fetchElement($activity, 'as:object')) {
 249                         logger('Empty object', LOGGER_DEBUG);
 250                         return;
 251                 }
 252
 253                 if (!JsonLD::fetchElement($activity, 'as:actor')) {
 254                         logger('Empty actor', LOGGER_DEBUG);
 255                         return;
 256
 257                 }
 258
 259                 // $trust_source is called by reference and is set to true if the content was retrieved successfully
 260                 $object_data = self::prepareObjectData($activity, $uid, $trust_source);
 261                 if (empty($object_data)) {
 262                         logger('No object data found', LOGGER_DEBUG);
 263                         return;
 264                 }
 265
 266                 if (!$trust_source) {
 267                         logger('No trust for activity type "' . $type . '", so we quit now.', LOGGER_DEBUG);
 268                         return;
 269                 }
 270
 271                 // Internal flag for thread completion. See Processor.php
 272                 if (!empty($activity['thread-completion'])) {
 273                         $object_data['thread-completion'] = $activity['thread-completion'];
 274                 }
 275
 276                 switch ($type) {
 277                         case 'as:Create':
 278                         case 'as:Announce':
 279                                 ActivityPub\Processor::createItem($object_data, $body);
 280                                 break;
 281
 282                         case 'as:Like':
 283                                 ActivityPub\Processor::likeItem($object_data, $body);
 284                                 break;
 285
 286                         case 'as:Dislike':
 287                                 ActivityPub\Processor::dislikeItem($object_data, $body);
 288                                 break;
 289
 290                         case 'as:Update':
 291                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 292                                         /// @todo
 293                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 294                                         ActivityPub\Processor::updatePerson($object_data, $body);
 295                                 }
 296                                 break;
 297
 298                         case 'as:Delete':
 299                                 if ($object_data['object_type'] == 'as:Tombstone') {
 300                                         ActivityPub\Processor::deleteItem($object_data, $body);
 301                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 302                                         ActivityPub\Processor::deletePerson($object_data, $body);
 303                                 }
 304                                 break;
 305
 306                         case 'as:Follow':
 307                                 ActivityPub\Processor::followUser($object_data);
 308                                 break;
 309
 310                         case 'as:Accept':
 311                                 if ($object_data['object_type'] == 'as:Follow') {
 312                                         ActivityPub\Processor::acceptFollowUser($object_data);
 313                                 }
 314                                 break;
 315
 316                         case 'as:Reject':
 317                                 if ($object_data['object_type'] == 'as:Follow') {
 318                                         ActivityPub\Processor::rejectFollowUser($object_data);
 319                                 }
 320                                 break;
 321
 322                         case 'as:Undo':
 323                                 if ($object_data['object_type'] == 'as:Follow') {
 324                                         ActivityPub\Processor::undoFollowUser($object_data);
 325                                 } elseif (in_array($object_data['object_type'], self::ACTIVITY_TYPES)) {
 326                                         ActivityPub\Processor::undoActivity($object_data);
 327                                 }
 328                                 break;
 329
 330                         default:
 331                                 logger('Unknown activity: ' . $type, LOGGER_DEBUG);
 332                                 break;
 333                 }
 334         }
 335
 336         /**
 337          * Fetch the receiver list from an activity array
 338          *
 339          * @param array $activity
 340          * @param string $actor
 341          *
 342          * @return array with receivers (user id)
 343          */
 344         private static function getReceivers($activity, $actor)
 345         {
 346                 $receivers = [];
 347
 348                 // When it is an answer, we inherite the receivers from the parent
 349                 $replyto = JsonLD::fetchElement($activity, 'as:inReplyTo');
 350                 if (!empty($replyto)) {
 351                         $parents = Item::select(['uid'], ['uri' => $replyto]);
 352                         while ($parent = Item::fetch($parents)) {
 353                                 $receivers['uid:' . $parent['uid']] = $parent['uid'];
 354                         }
 355                 }
 356
 357                 if (!empty($actor)) {
 358                         $profile = APContact::getByURL($actor);
 359                         $followers = defaults($profile, 'followers', '');
 360
 361                         logger('Actor: ' . $actor . ' - Followers: ' . $followers, LOGGER_DEBUG);
 362                 } else {
 363                         logger('Empty actor', LOGGER_DEBUG);
 364                         $followers = '';
 365                 }
 366
 367                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
 368                         $receiver_list = JsonLD::fetchElementArray($activity, $element);
 369                         if (empty($receiver_list)) {
 370                                 continue;
 371                         }
 372
 373                         foreach ($receiver_list as $receiver) {
 374                                 if ($receiver == self::PUBLIC_COLLECTION) {
 375                                         $receivers['uid:0'] = 0;
 376                                 }
 377
 378                                 if (($receiver == self::PUBLIC_COLLECTION) && !empty($actor)) {
 379                                         // This will most likely catch all OStatus connections to Mastodon
 380                                         $condition = ['alias' => [$actor, normalise_link($actor)], 'rel' => [Contact::SHARING, Contact::FRIEND]
 381                                                 , 'archive' => false, 'pending' => false];
 382                                         $contacts = DBA::select('contact', ['uid'], $condition);
 383                                         while ($contact = DBA::fetch($contacts)) {
 384                                                 if ($contact['uid'] != 0) {
 385                                                         $receivers['uid:' . $contact['uid']] = $contact['uid'];
 386                                                 }
 387                                         }
 388                                         DBA::close($contacts);
 389                                 }
 390
 391                                 if (in_array($receiver, [$followers, self::PUBLIC_COLLECTION]) && !empty($actor)) {
 392                                         $condition = ['nurl' => normalise_link($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
 393                                                 'network' => Protocol::ACTIVITYPUB, 'archive' => false, 'pending' => false];
 394                                         $contacts = DBA::select('contact', ['uid'], $condition);
 395                                         while ($contact = DBA::fetch($contacts)) {
 396                                                 if ($contact['uid'] != 0) {
 397                                                         $receivers['uid:' . $contact['uid']] = $contact['uid'];
 398                                                 }
 399                                         }
 400                                         DBA::close($contacts);
 401                                         continue;
 402                                 }
 403
 404                                 $condition = ['self' => true, 'nurl' => normalise_link($receiver)];
 405                                 $contact = DBA::selectFirst('contact', ['uid'], $condition);
 406                                 if (!DBA::isResult($contact)) {
 407                                         continue;
 408                                 }
 409                                 $receivers['uid:' . $contact['uid']] = $contact['uid'];
 410                         }
 411                 }
 412
 413                 self::switchContacts($receivers, $actor);
 414
 415                 return $receivers;
 416         }
 417
 418         /**
 419          * Switches existing contacts to ActivityPub
 420          *
 421          * @param integer $cid Contact ID
 422          * @param integer $uid User ID
 423          * @param string $url Profile URL
 424          */
 425         private static function switchContact($cid, $uid, $url)
 426         {
 427                 $profile = ActivityPub::probeProfile($url);
 428                 if (empty($profile)) {
 429                         return;
 430                 }
 431
 432                 logger('Switch contact ' . $cid . ' (' . $profile['url'] . ') for user ' . $uid . ' to ActivityPub');
 433
 434                 $photo = $profile['photo'];
 435                 unset($profile['photo']);
 436                 unset($profile['baseurl']);
 437
 438                 $profile['nurl'] = normalise_link($profile['url']);
 439                 DBA::update('contact', $profile, ['id' => $cid]);
 440
 441                 Contact::updateAvatar($photo, $uid, $cid);
 442
 443                 // Send a new follow request to be sure that the connection still exists
 444                 if (($uid != 0) && DBA::exists('contact', ['id' => $cid, 'rel' => [Contact::SHARING, Contact::FRIEND]])) {
 445                         ActivityPub\Transmitter::sendActivity('Follow', $profile['url'], $uid);
 446                         logger('Send a new follow request to ' . $profile['url'] . ' for user ' . $uid, LOGGER_DEBUG);
 447                 }
 448         }
 449
 450         /**
 451          *
 452          *
 453          * @param $receivers
 454          * @param $actor
 455          */
 456         private static function switchContacts($receivers, $actor)
 457         {
 458                 if (empty($actor)) {
 459                         return;
 460                 }
 461
 462                 foreach ($receivers as $receiver) {
 463                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver, 'network' => Protocol::OSTATUS, 'nurl' => normalise_link($actor)]);
 464                         if (DBA::isResult($contact)) {
 465                                 self::switchContact($contact['id'], $receiver, $actor);
 466                         }
 467
 468                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver, 'network' => Protocol::OSTATUS, 'alias' => [normalise_link($actor), $actor]]);
 469                         if (DBA::isResult($contact)) {
 470                                 self::switchContact($contact['id'], $receiver, $actor);
 471                         }
 472                 }
 473         }
 474
 475         /**
 476          *
 477          *
 478          * @param $object_data
 479          * @param array $activity
 480          *
 481          * @return
 482          */
 483         private static function addActivityFields($object_data, $activity)
 484         {
 485                 if (!empty($activity['published']) && empty($object_data['published'])) {
 486                         $object_data['published'] = JsonLD::fetchElement($activity, 'published', '@value');
 487                 }
 488
 489                 if (!empty($activity['updated']) && empty($object_data['updated'])) {
 490                         $object_data['updated'] = JsonLD::fetchElement($activity, 'updated', '@value');
 491                 }
 492
 493                 if (!empty($activity['diaspora:guid']) && empty($object_data['diaspora:guid'])) {
 494                         $object_data['diaspora:guid'] = JsonLD::fetchElement($activity, 'diaspora:guid');
 495                 }
 496
 497                 if (!empty($activity['inReplyTo']) && empty($object_data['parent-uri'])) {
 498                         $object_data['parent-uri'] = JsonLD::fetchElement($activity, 'inReplyTo');
 499                 }
 500
 501                 if (!empty($activity['instrument'])) {
 502                         $object_data['service'] = JsonLD::fetchElement($activity, 'instrument', 'name', 'type', 'Service');
 503                 }
 504                 return $object_data;
 505         }
 506
 507         /**
 508          * Fetches the object data from external ressources if needed
 509          *
 510          * @param string  $object_id    Object ID of the the provided object
 511          * @param array   $object       The provided object array
 512          * @param boolean $trust_source Do we trust the provided object?
 513          *
 514          * @return array with trusted and valid object data
 515          */
 516         private static function fetchObject($object_id, $object = [], $trust_source = false)
 517         {
 518                 // By fetching the type we check if the object is complete.
 519                 $type = JsonLD::fetchElement($object, '@type');
 520
 521                 if (!$trust_source || empty($type)) {
 522                         $data = ActivityPub::fetchContent($object_id);
 523                         if (!empty($data)) {
 524                                 $object = JsonLD::compact($data);
 525                                 logger('Fetched content for ' . $object_id, LOGGER_DEBUG);
 526                         } else {
 527                                 logger('Empty content for ' . $object_id . ', check if content is available locally.', LOGGER_DEBUG);
 528
 529                                 $item = Item::selectFirst([], ['uri' => $object_id]);
 530                                 if (!DBA::isResult($item)) {
 531                                         logger('Object with url ' . $object_id . ' was not found locally.', LOGGER_DEBUG);
 532                                         return false;
 533                                 }
 534                                 logger('Using already stored item for url ' . $object_id, LOGGER_DEBUG);
 535                                 $data = ActivityPub\Transmitter::createNote($item);
 536                                 $object = JsonLD::compact($data);
 537                         }
 538                 } else {
 539                         logger('Using original object for url ' . $object_id, LOGGER_DEBUG);
 540                 }
 541
 542                 $type = JsonLD::fetchElement($object, '@type');
 543
 544                 if (empty($type)) {
 545                         logger('Empty type', LOGGER_DEBUG);
 546                         return false;
 547                 }
 548
 549                 if (in_array($type, self::CONTENT_TYPES)) {
 550                         return self::processObject($object);
 551                 }
 552
 553                 if ($type == 'as:Announce') {
 554                         $object_id = JsonLD::fetchElement($object, 'object');
 555                         if (empty($object_id)) {
 556                                 return false;
 557                         }
 558                         return self::fetchObject($object_id);
 559                 }
 560
 561                 logger('Unhandled object type: ' . $type, LOGGER_DEBUG);
 562         }
 563
 564         /**
 565          * Convert tags from JSON-LD format into a simplified format
 566          *
 567          * @param array $tags Tags in JSON-LD format
 568          *
 569          * @return array with tags in a simplified format
 570          */
 571         private static function processTags($tags)
 572         {
 573                 $taglist = [];
 574
 575                 if (empty($tags)) {
 576                         return [];
 577                 }
 578
 579                 foreach ($tags as $tag) {
 580                         if (empty($tag)) {
 581                                 continue;
 582                         }
 583
 584                         $taglist[] = ['type' => str_replace('as:', '', JsonLD::fetchElement($tag, '@type')),
 585                                 'href' => JsonLD::fetchElement($tag, 'as:href'),
 586                                 'name' => JsonLD::fetchElement($tag, 'as:name')];
 587                 }
 588                 return $taglist;
 589         }
 590
 591         /**
 592          * Convert attachments from JSON-LD format into a simplified format
 593          *
 594          * @param array $attachments Attachments in JSON-LD format
 595          *
 596          * @return array with attachmants in a simplified format
 597          */
 598         private static function processAttachments($attachments)
 599         {
 600                 $attachlist = [];
 601
 602                 if (empty($attachments)) {
 603                         return [];
 604                 }
 605
 606                 foreach ($attachments as $attachment) {
 607                         if (empty($attachment)) {
 608                                 continue;
 609                         }
 610
 611                         $attachlist[] = ['type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
 612                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType'),
 613                                 'name' => JsonLD::fetchElement($attachment, 'as:name'),
 614                                 'url' => JsonLD::fetchElement($attachment, 'as:url')];
 615                 }
 616                 return $attachlist;
 617         }
 618
 619         /**
 620          * Fetches data from the object part of an activity
 621          *
 622          * @param array $object
 623          *
 624          * @return array
 625          */
 626         private static function processObject($object)
 627         {
 628                 if (!JsonLD::fetchElement($object, '@id')) {
 629                         return false;
 630                 }
 631
 632                 $object_data = [];
 633                 $object_data['object_type'] = JsonLD::fetchElement($object, '@type');
 634                 $object_data['id'] = JsonLD::fetchElement($object, '@id');
 635
 636                 $object_data['reply-to-id'] = JsonLD::fetchElement($object, 'as:inReplyTo');
 637
 638                 if (empty($object_data['reply-to-id'])) {
 639                         $object_data['reply-to-id'] = $object_data['id'];
 640                 }
 641
 642                 $object_data['published'] = JsonLD::fetchElement($object, 'as:published', '@value');
 643                 $object_data['updated'] = JsonLD::fetchElement($object, 'as:updated', '@value');
 644
 645                 if (empty($object_data['updated'])) {
 646                         $object_data['updated'] = $object_data['published'];
 647                 }
 648
 649                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
 650                         $object_data['published'] = $object_data['updated'];
 651                 }
 652
 653                 $actor = JsonLD::fetchElement($object, 'as:attributedTo');
 654                 if (empty($actor)) {
 655                         $actor = JsonLD::fetchElement($object, 'as:actor');
 656                 }
 657
 658                 $object_data['diaspora:guid'] = JsonLD::fetchElement($object, 'diaspora:guid');
 659                 $object_data['diaspora:comment'] = JsonLD::fetchElement($object, 'diaspora:comment');
 660                 $object_data['actor'] = $object_data['author'] = $actor;
 661                 $object_data['context'] = JsonLD::fetchElement($object, 'as:context');
 662                 $object_data['conversation'] = JsonLD::fetchElement($object, 'ostatus:conversation');
 663                 $object_data['sensitive'] = JsonLD::fetchElement($object, 'as:sensitive');
 664                 $object_data['name'] = JsonLD::fetchElement($object, 'as:name');
 665                 $object_data['summary'] = JsonLD::fetchElement($object, 'as:summary');
 666                 $object_data['content'] = JsonLD::fetchElement($object, 'as:content');
 667                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/bbcode');
 668                 $object_data['location'] = JsonLD::fetchElement($object, 'as:location', 'as:name', '@type', 'as:Place');
 669                 $object_data['attachments'] = self::processAttachments(JsonLD::fetchElementArray($object, 'as:attachment'));
 670                 $object_data['tags'] = self::processTags(JsonLD::fetchElementArray($object, 'as:tag'));
 671 //              $object_data['service'] = JsonLD::fetchElement($object, 'instrument', 'name', 'type', 'Service'); // todo
 672                 $object_data['service'] = null;
 673                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'as:url');
 674
 675                 // Special treatment for Hubzilla links
 676                 if (is_array($object_data['alternate-url'])) {
 677                         if (!empty($object['as:url'])) {
 678                                 $object_data['alternate-url'] = JsonLD::fetchElement($object['as:url'], 'as:href');
 679                         } else {
 680                                 $object_data['alternate-url'] = null;
 681                         }
 682                 }
 683
 684                 $object_data['receiver'] = self::getReceivers($object, $object_data['actor']);
 685
 686                 // Common object data:
 687
 688                 // Unhandled
 689                 // @context, type, actor, signature, mediaType, duration, replies, icon
 690
 691                 // Also missing: (Defined in the standard, but currently unused)
 692                 // audience, preview, endTime, startTime, generator, image
 693
 694                 // Data in Notes:
 695
 696                 // Unhandled
 697                 // contentMap, announcement_count, announcements, context_id, likes, like_count
 698                 // inReplyToStatusId, shares, quoteUrl, statusnetConversationId
 699
 700                 // Data in video:
 701
 702                 // To-Do?
 703                 // category, licence, language, commentsEnabled
 704
 705                 // Unhandled
 706                 // views, waitTranscoding, state, support, subtitleLanguage
 707                 // likes, dislikes, shares, comments
 708
 709                 return $object_data;
 710         }
 711 }