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