src/Protocol/ActivityPub/Receiver.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2020, Friendica
   4  *
   5  * @license GNU AGPL version 3 or any later version
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU Affero General Public License as
   9  * published by the Free Software Foundation, either version 3 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU Affero General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Affero General Public License
  18  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  19  *
  20  */
  21
  22 namespace Friendica\Protocol\ActivityPub;
  23
  24 use Friendica\Content\Text\BBCode;
  25 use Friendica\Database\DBA;
  26 use Friendica\Content\Text\HTML;
  27 use Friendica\Content\Text\Markdown;
  28 use Friendica\Core\Logger;
  29 use Friendica\Core\Protocol;
  30 use Friendica\Model\Contact;
  31 use Friendica\Model\APContact;
  32 use Friendica\Model\Item;
  33 use Friendica\Model\User;
  34 use Friendica\Protocol\Activity;
  35 use Friendica\Protocol\ActivityPub;
  36 use Friendica\Util\HTTPSignature;
  37 use Friendica\Util\JsonLD;
  38 use Friendica\Util\LDSignature;
  39 use Friendica\Util\Strings;
  40
  41 /**
  42  * ActivityPub Receiver Protocol class
  43  *
  44  * To-Do:
  45  * @todo Undo Announce
  46  *
  47  * Check what this is meant to do:
  48  * - Add
  49  * - Block
  50  * - Flag
  51  * - Remove
  52  * - Undo Block
  53  */
  54 class Receiver
  55 {
  56         const PUBLIC_COLLECTION = 'as:Public';
  57         const ACCOUNT_TYPES = ['as:Person', 'as:Organization', 'as:Service', 'as:Group', 'as:Application'];
  58         const CONTENT_TYPES = ['as:Note', 'as:Article', 'as:Video', 'as:Image', 'as:Event', 'as:Audio'];
  59         const ACTIVITY_TYPES = ['as:Like', 'as:Dislike', 'as:Accept', 'as:Reject', 'as:TentativeAccept'];
  60
  61         const TARGET_UNKNOWN = 0;
  62         const TARGET_TO = 1;
  63         const TARGET_CC = 2;
  64         const TARGET_BTO = 3;
  65         const TARGET_BCC = 4;
  66         const TARGET_FOLLOWER = 5;
  67
  68         /**
  69          * Checks if the web request is done for the AP protocol
  70          *
  71          * @return bool is it AP?
  72          */
  73         public static function isRequest()
  74         {
  75                 return stristr($_SERVER['HTTP_ACCEPT'] ?? '', 'application/activity+json') ||
  76                         stristr($_SERVER['HTTP_ACCEPT'] ?? '', 'application/ld+json');
  77         }
  78
  79         /**
  80          * Checks incoming message from the inbox
  81          *
  82          * @param         $body
  83          * @param         $header
  84          * @param integer $uid User ID
  85          * @throws \Exception
  86          */
  87         public static function processInbox($body, $header, $uid)
  88         {
  89                 $http_signer = HTTPSignature::getSigner($body, $header);
  90                 if (empty($http_signer)) {
  91                         Logger::warning('Invalid HTTP signature, message will be discarded.');
  92                         return;
  93                 } else {
  94                         Logger::info('Valid HTTP signature', ['signer' => $http_signer]);
  95                 }
  96
  97                 $signer = [$http_signer];
  98                 $activity = json_decode($body, true);
  99
 100                 if (empty($activity)) {
 101                         Logger::warning('Invalid body.');
 102                         return;
 103                 }
 104
 105                 $ldactivity = JsonLD::compact($activity);
 106
 107                 $actor = JsonLD::fetchElement($ldactivity, 'as:actor', '@id');
 108
 109                 Logger::info('Message for user ' . $uid . ' is from actor ' . $actor);
 110
 111                 if (LDSignature::isSigned($activity)) {
 112                         $ld_signer = LDSignature::getSigner($activity);
 113                         if (empty($ld_signer)) {
 114                                 Logger::log('Invalid JSON-LD signature from ' . $actor, Logger::DEBUG);
 115                         } elseif ($ld_signer != $http_signer) {
 116                                 $signer[] = $ld_signer;
 117                         }
 118                         if (!empty($ld_signer && ($actor == $http_signer))) {
 119                                 Logger::log('The HTTP and the JSON-LD signature belong to ' . $ld_signer, Logger::DEBUG);
 120                                 $trust_source = true;
 121                         } elseif (!empty($ld_signer)) {
 122                                 Logger::log('JSON-LD signature is signed by ' . $ld_signer, Logger::DEBUG);
 123                                 $trust_source = true;
 124                         } elseif ($actor == $http_signer) {
 125                                 Logger::log('Bad JSON-LD signature, but HTTP signer fits the actor.', Logger::DEBUG);
 126                                 $trust_source = true;
 127                         } else {
 128                                 Logger::log('Invalid JSON-LD signature and the HTTP signer is different.', Logger::DEBUG);
 129                                 $trust_source = false;
 130                         }
 131                 } elseif ($actor == $http_signer) {
 132                         Logger::log('Trusting post without JSON-LD signature, The actor fits the HTTP signer.', Logger::DEBUG);
 133                         $trust_source = true;
 134                 } else {
 135                         Logger::log('No JSON-LD signature, different actor.', Logger::DEBUG);
 136                         $trust_source = false;
 137                 }
 138
 139                 self::processActivity($ldactivity, $body, $uid, $trust_source, true, $signer);
 140         }
 141
 142         /**
 143          * Fetches the object type for a given object id
 144          *
 145          * @param array   $activity
 146          * @param string  $object_id Object ID of the the provided object
 147          * @param integer $uid       User ID
 148          *
 149          * @return string with object type
 150          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 151          * @throws \ImagickException
 152          */
 153         private static function fetchObjectType($activity, $object_id, $uid = 0)
 154         {
 155                 if (!empty($activity['as:object'])) {
 156                         $object_type = JsonLD::fetchElement($activity['as:object'], '@type');
 157                         if (!empty($object_type)) {
 158                                 return $object_type;
 159                         }
 160                 }
 161
 162                 if (Item::exists(['uri' => $object_id, 'gravity' => [GRAVITY_PARENT, GRAVITY_COMMENT]])) {
 163                         // We just assume "note" since it doesn't make a difference for the further processing
 164                         return 'as:Note';
 165                 }
 166
 167                 $profile = APContact::getByURL($object_id);
 168                 if (!empty($profile['type'])) {
 169                         return 'as:' . $profile['type'];
 170                 }
 171
 172                 $data = ActivityPub::fetchContent($object_id, $uid);
 173                 if (!empty($data)) {
 174                         $object = JsonLD::compact($data);
 175                         $type = JsonLD::fetchElement($object, '@type');
 176                         if (!empty($type)) {
 177                                 return $type;
 178                         }
 179                 }
 180
 181                 return null;
 182         }
 183
 184         /**
 185          * Prepare the object array
 186          *
 187          * @param array   $activity     Array with activity data
 188          * @param integer $uid          User ID
 189          * @param boolean $push         Message had been pushed to our system
 190          * @param boolean $trust_source Do we trust the source?
 191          *
 192          * @return array with object data
 193          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 194          * @throws \ImagickException
 195          */
 196         public static function prepareObjectData($activity, $uid, $push, &$trust_source)
 197         {
 198                 $id = JsonLD::fetchElement($activity, '@id');
 199                 if (!empty($id) && !$trust_source) {
 200                         $fetched_activity = ActivityPub::fetchContent($id, $uid ?? 0);
 201                         if (!empty($fetched_activity)) {
 202                                 $object = JsonLD::compact($fetched_activity);
 203                                 $fetched_id = JsonLD::fetchElement($object, '@id');
 204                                 if ($fetched_id == $id) {
 205                                         Logger::info('Activity had been fetched successfully', ['id' => $id]);
 206                                         $trust_source = true;
 207                                         $activity = $object;
 208                                 } else {
 209                                         Logger::info('Activity id is not equal', ['id' => $id, 'fetched' => $fetched_id]);
 210                                 }
 211                         } else {
 212                                 Logger::info('Activity could not been fetched', ['id' => $id]);
 213                         }
 214                 }
 215
 216                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 217                 if (empty($actor)) {
 218                         Logger::info('Empty actor', ['activity' => $activity]);
 219                         return [];
 220                 }
 221
 222                 $type = JsonLD::fetchElement($activity, '@type');
 223
 224                 // Fetch all receivers from to, cc, bto and bcc
 225                 $receiverdata = self::getReceivers($activity, $actor);
 226                 $receivers = $reception_types = [];
 227                 foreach ($receiverdata as $key => $data) {
 228                         $receivers[$key] = $data['uid'];
 229                         $reception_types[$data['uid']] = $data['type'] ?? 0;
 230                 }
 231
 232                 // When it is a delivery to a personal inbox we add that user to the receivers
 233                 if (!empty($uid)) {
 234                         $additional = ['uid:' . $uid => $uid];
 235                         $receivers = array_merge($receivers, $additional);
 236                         if (empty($reception_types[$uid]) || in_array($reception_types[$uid], [self::TARGET_UNKNOWN, self::TARGET_FOLLOWER])) {
 237                                 $reception_types[$uid] = self::TARGET_BCC;
 238                         }
 239                 } else {
 240                         // We possibly need some user to fetch private content,
 241                         // so we fetch the first out ot the list.
 242                         $uid = self::getFirstUserFromReceivers($receivers);
 243                 }
 244
 245                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 246                 if (empty($object_id)) {
 247                         Logger::log('No object found', Logger::DEBUG);
 248                         return [];
 249                 }
 250
 251                 if (!is_string($object_id)) {
 252                         Logger::info('Invalid object id', ['object' => $object_id]);
 253                         return [];
 254                 }
 255
 256                 $object_type = self::fetchObjectType($activity, $object_id, $uid);
 257
 258                 // Fetch the content only on activities where this matters
 259                 if (in_array($type, ['as:Create', 'as:Update', 'as:Announce'])) {
 260                         // Always fetch on "Announce"
 261                         $object_data = self::fetchObject($object_id, $activity['as:object'], $trust_source && ($type != 'as:Announce'), $uid);
 262                         if (empty($object_data)) {
 263                                 Logger::log("Object data couldn't be processed", Logger::DEBUG);
 264                                 return [];
 265                         }
 266
 267                         $object_data['object_id'] = $object_id;
 268
 269                         if ($type == 'as:Announce') {
 270                                 $object_data['push'] = false;
 271                         } else {
 272                                 $object_data['push'] = $push;
 273                         }
 274
 275                         // Test if it is an answer to a mail
 276                         if (DBA::exists('mail', ['uri' => $object_data['reply-to-id']])) {
 277                                 $object_data['directmessage'] = true;
 278                         } else {
 279                                 $object_data['directmessage'] = JsonLD::fetchElement($activity, 'litepub:directMessage');
 280                         }
 281                 } elseif (in_array($type, array_merge(self::ACTIVITY_TYPES, ['as:Follow'])) && in_array($object_type, self::CONTENT_TYPES)) {
 282                         // Create a mostly empty array out of the activity data (instead of the object).
 283                         // This way we later don't have to check for the existence of ech individual array element.
 284                         $object_data = self::processObject($activity);
 285                         $object_data['name'] = $type;
 286                         $object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 287                         $object_data['object_id'] = $object_id;
 288                         $object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
 289                 } elseif (in_array($type, ['as:Add'])) {
 290                         $object_data = [];
 291                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 292                         $object_data['target_id'] = JsonLD::fetchElement($activity, 'as:target', '@id');
 293                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 294                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 295                         $object_data['object_content'] = JsonLD::fetchElement($activity['as:object'], 'as:content', '@type');
 296                 } else {
 297                         $object_data = [];
 298                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 299                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 300                         $object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor', '@id');
 301                         $object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
 302                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 303
 304                         // An Undo is done on the object of an object, so we need that type as well
 305                         if (($type == 'as:Undo') && !empty($object_data['object_object'])) {
 306                                 $object_data['object_object_type'] = self::fetchObjectType([], $object_data['object_object'], $uid);
 307                         }
 308                 }
 309
 310                 $object_data = self::addActivityFields($object_data, $activity);
 311
 312                 if (empty($object_data['object_type'])) {
 313                         $object_data['object_type'] = $object_type;
 314                 }
 315
 316                 $object_data['type'] = $type;
 317                 $object_data['actor'] = $actor;
 318                 $object_data['item_receiver'] = $receivers;
 319                 $object_data['receiver'] = array_merge($object_data['receiver'] ?? [], $receivers);
 320                 $object_data['reception_type'] = $reception_types;
 321
 322                 $author = $object_data['author'] ?? $actor;
 323                 if (!empty($author) && !empty($object_data['id'])) {
 324                         $author_host = parse_url($author, PHP_URL_HOST);
 325                         $id_host = parse_url($object_data['id'], PHP_URL_HOST);
 326                         if ($author_host == $id_host) {
 327                                 Logger::info('Valid hosts', ['type' => $type, 'host' => $id_host]);
 328                         } else {
 329                                 Logger::notice('Differing hosts on author and id', ['type' => $type, 'author' => $author_host, 'id' => $id_host]);
 330                                 $trust_source = false;
 331                         }
 332                 }
 333
 334                 Logger::log('Processing ' . $object_data['type'] . ' ' . $object_data['object_type'] . ' ' . $object_data['id'], Logger::DEBUG);
 335
 336                 return $object_data;
 337         }
 338
 339         /**
 340          * Fetches the first user id from the receiver array
 341          *
 342          * @param array $receivers Array with receivers
 343          * @return integer user id;
 344          */
 345         public static function getFirstUserFromReceivers($receivers)
 346         {
 347                 foreach ($receivers as $receiver) {
 348                         if (!empty($receiver)) {
 349                                 return $receiver;
 350                         }
 351                 }
 352                 return 0;
 353         }
 354
 355         /**
 356          * Processes the activity object
 357          *
 358          * @param array   $activity     Array with activity data
 359          * @param string  $body
 360          * @param integer $uid          User ID
 361          * @param boolean $trust_source Do we trust the source?
 362          * @param boolean $push         Message had been pushed to our system
 363          * @throws \Exception
 364          */
 365         public static function processActivity($activity, string $body = '', int $uid = null, bool $trust_source = false, bool $push = false, array $signer = [])
 366         {
 367                 $type = JsonLD::fetchElement($activity, '@type');
 368                 if (!$type) {
 369                         Logger::info('Empty type', ['activity' => $activity]);
 370                         return;
 371                 }
 372
 373                 if (!JsonLD::fetchElement($activity, 'as:object', '@id')) {
 374                         Logger::info('Empty object', ['activity' => $activity]);
 375                         return;
 376                 }
 377
 378                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 379                 if (empty($actor)) {
 380                         Logger::info('Empty actor', ['activity' => $activity]);
 381                         return;
 382                 }
 383
 384                 if (is_array($activity['as:object'])) {
 385                         $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
 386                 } else {
 387                         $attributed_to = '';
 388                 }
 389
 390                 // Test the provided signatures against the actor and "attributedTo"
 391                 if ($trust_source) {
 392                         if (!empty($attributed_to) && !empty($actor)) {
 393                                 $trust_source = (in_array($actor, $signer) && in_array($attributed_to, $signer));
 394                         } else {
 395                                 $trust_source = in_array($actor, $signer);
 396                         }
 397                 }
 398
 399                 // $trust_source is called by reference and is set to true if the content was retrieved successfully
 400                 $object_data = self::prepareObjectData($activity, $uid, $push, $trust_source);
 401                 if (empty($object_data)) {
 402                         Logger::info('No object data found', ['activity' => $activity]);
 403                         return;
 404                 }
 405
 406                 if (!$trust_source) {
 407                         Logger::info('Activity trust could not be achieved.',  ['id' => $object_data['object_id'], 'type' => $type, 'signer' => $signer, 'actor' => $actor, 'attributedTo' => $attributed_to]);
 408                         return;
 409                 }
 410
 411                 if (!empty($body) && empty($object_data['raw'])) {
 412                         $object_data['raw'] = $body;
 413                 }
 414
 415                 // Internal flag for thread completion. See Processor.php
 416                 if (!empty($activity['thread-completion'])) {
 417                         $object_data['thread-completion'] = $activity['thread-completion'];
 418                 }
 419
 420                 switch ($type) {
 421                         case 'as:Create':
 422                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 423                                         $item = ActivityPub\Processor::createItem($object_data);
 424                                         ActivityPub\Processor::postItem($object_data, $item);
 425                                 }
 426                                 break;
 427
 428                         case 'as:Add':
 429                                 if ($object_data['object_type'] == 'as:tag') {
 430                                         ActivityPub\Processor::addTag($object_data);
 431                                 }
 432                                 break;
 433
 434                         case 'as:Announce':
 435                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 436                                         $object_data['thread-completion'] = true;
 437
 438                                         $item = ActivityPub\Processor::createItem($object_data);
 439                                         ActivityPub\Processor::postItem($object_data, $item);
 440
 441                                         $announce_object_data = self::processObject($activity);
 442                                         $announce_object_data['name'] = $type;
 443                                         $announce_object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 444                                         $announce_object_data['object_id'] = $object_data['object_id'];
 445                                         $announce_object_data['object_type'] = $object_data['object_type'];
 446                                         $announce_object_data['push'] = $push;
 447
 448                                         if (!empty($body)) {
 449                                                 $announce_object_data['raw'] = $body;
 450                                         }
 451
 452                                         ActivityPub\Processor::createActivity($announce_object_data, Activity::ANNOUNCE);
 453                                 }
 454                                 break;
 455
 456                         case 'as:Like':
 457                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 458                                         ActivityPub\Processor::createActivity($object_data, Activity::LIKE);
 459                                 }
 460                                 break;
 461
 462                         case 'as:Dislike':
 463                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 464                                         ActivityPub\Processor::createActivity($object_data, Activity::DISLIKE);
 465                                 }
 466                                 break;
 467
 468                         case 'as:TentativeAccept':
 469                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 470                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDMAYBE);
 471                                 }
 472                                 break;
 473
 474                         case 'as:Update':
 475                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 476                                         ActivityPub\Processor::updateItem($object_data);
 477                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 478                                         ActivityPub\Processor::updatePerson($object_data);
 479                                 }
 480                                 break;
 481
 482                         case 'as:Delete':
 483                                 if ($object_data['object_type'] == 'as:Tombstone') {
 484                                         ActivityPub\Processor::deleteItem($object_data);
 485                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 486                                         ActivityPub\Processor::deletePerson($object_data);
 487                                 }
 488                                 break;
 489
 490                         case 'as:Follow':
 491                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 492                                         ActivityPub\Processor::followUser($object_data);
 493                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 494                                         $object_data['reply-to-id'] = $object_data['object_id'];
 495                                         ActivityPub\Processor::createActivity($object_data, Activity::FOLLOW);
 496                                 }
 497                                 break;
 498
 499                         case 'as:Accept':
 500                                 if ($object_data['object_type'] == 'as:Follow') {
 501                                         ActivityPub\Processor::acceptFollowUser($object_data);
 502                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 503                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTEND);
 504                                 }
 505                                 break;
 506
 507                         case 'as:Reject':
 508                                 if ($object_data['object_type'] == 'as:Follow') {
 509                                         ActivityPub\Processor::rejectFollowUser($object_data);
 510                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 511                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDNO);
 512                                 }
 513                                 break;
 514
 515                         case 'as:Undo':
 516                                 if (($object_data['object_type'] == 'as:Follow') &&
 517                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 518                                         ActivityPub\Processor::undoFollowUser($object_data);
 519                                 } elseif (($object_data['object_type'] == 'as:Accept') &&
 520                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 521                                         ActivityPub\Processor::rejectFollowUser($object_data);
 522                                 } elseif (in_array($object_data['object_type'], self::ACTIVITY_TYPES) &&
 523                                         in_array($object_data['object_object_type'], self::CONTENT_TYPES)) {
 524                                         ActivityPub\Processor::undoActivity($object_data);
 525                                 }
 526                                 break;
 527
 528                         default:
 529                                 Logger::log('Unknown activity: ' . $type . ' ' . $object_data['object_type'], Logger::DEBUG);
 530                                 break;
 531                 }
 532         }
 533
 534         /**
 535          * Fetch the receiver list from an activity array
 536          *
 537          * @param array   $activity
 538          * @param string  $actor
 539          * @param array   $tags
 540          * @param boolean $fetch_unlisted
 541          *
 542          * @return array with receivers (user id)
 543          * @throws \Exception
 544          */
 545         private static function getReceivers($activity, $actor, $tags = [], $fetch_unlisted = false)
 546         {
 547                 $receivers = [];
 548
 549                 // When it is an answer, we inherite the receivers from the parent
 550                 $replyto = JsonLD::fetchElement($activity, 'as:inReplyTo', '@id');
 551                 if (!empty($replyto)) {
 552                         // Fix possibly wrong item URI (could be an answer to a plink uri)
 553                         $fixedReplyTo = Item::getURIByLink($replyto);
 554                         $replyto = $fixedReplyTo ?: $replyto;
 555
 556                         $parents = Item::select(['uid'], ['uri' => $replyto]);
 557                         while ($parent = Item::fetch($parents)) {
 558                                 $receivers['uid:' . $parent['uid']] = ['uid' => $parent['uid']];
 559                         }
 560                 }
 561
 562                 if (!empty($actor)) {
 563                         $profile = APContact::getByURL($actor);
 564                         $followers = $profile['followers'] ?? '';
 565
 566                         Logger::log('Actor: ' . $actor . ' - Followers: ' . $followers, Logger::DEBUG);
 567                 } else {
 568                         Logger::info('Empty actor', ['activity' => $activity]);
 569                         $followers = '';
 570                 }
 571
 572                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
 573                         $receiver_list = JsonLD::fetchElementArray($activity, $element, '@id');
 574                         if (empty($receiver_list)) {
 575                                 continue;
 576                         }
 577
 578                         foreach ($receiver_list as $receiver) {
 579                                 if ($receiver == self::PUBLIC_COLLECTION) {
 580                                         $receivers['uid:0'] = ['uid' => 0, 'type' => self::TARGET_UNKNOWN];
 581                                 }
 582
 583                                 // Add receiver "-1" for unlisted posts
 584                                 if ($fetch_unlisted && ($receiver == self::PUBLIC_COLLECTION) && ($element == 'as:cc')) {
 585                                         $receivers['uid:-1'] = ['uid' => -1, 'type' => self::TARGET_UNKNOWN];
 586                                 }
 587
 588                                 // Fetch the receivers for the public and the followers collection
 589                                 if (in_array($receiver, [$followers, self::PUBLIC_COLLECTION]) && !empty($actor)) {
 590                                         $receivers = self::getReceiverForActor($actor, $tags, $receivers);
 591                                         continue;
 592                                 }
 593
 594                                 // Fetching all directly addressed receivers
 595                                 $condition = ['self' => true, 'nurl' => Strings::normaliseLink($receiver)];
 596                                 $contact = DBA::selectFirst('contact', ['uid', 'contact-type'], $condition);
 597                                 if (!DBA::isResult($contact)) {
 598                                         continue;
 599                                 }
 600
 601                                 // Check if the potential receiver is following the actor
 602                                 // Exception: The receiver is targetted via "to" or this is a comment
 603                                 if ((($element != 'as:to') && empty($replyto)) || ($contact['contact-type'] == Contact::TYPE_COMMUNITY)) {
 604                                         $networks = Protocol::FEDERATED;
 605                                         $condition = ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
 606                                                 'network' => $networks, 'archive' => false, 'pending' => false, 'uid' => $contact['uid']];
 607
 608                                         // Forum posts are only accepted from forum contacts
 609                                         if ($contact['contact-type'] == Contact::TYPE_COMMUNITY) {
 610                                                 $condition['rel'] = [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER];
 611                                         }
 612
 613                                         if (!DBA::exists('contact', $condition)) {
 614                                                 continue;
 615                                         }
 616                                 }
 617
 618                                 $type = $receivers['uid:' . $contact['uid']]['type'] ?? self::TARGET_UNKNOWN;
 619                                 if (in_array($type, [self::TARGET_UNKNOWN, self::TARGET_FOLLOWER])) {
 620                                         switch ($element) {
 621                                                 case 'as:to':
 622                                                         $type = self::TARGET_TO;
 623                                                         break;
 624                                                 case 'as:cc':
 625                                                         $type = self::TARGET_CC;
 626                                                         break;
 627                                                 case 'as:bto':
 628                                                         $type = self::TARGET_BTO;
 629                                                         break;
 630                                                 case 'as:bcc':
 631                                                         $type = self::TARGET_BCC;
 632                                                         break;
 633                                         }
 634
 635                                         $receivers['uid:' . $contact['uid']] = ['uid' => $contact['uid'], 'type' => $type];
 636                                 }
 637                         }
 638                 }
 639
 640                 self::switchContacts($receivers, $actor);
 641
 642                 return $receivers;
 643         }
 644
 645         /**
 646          * Fetch the receiver list of a given actor
 647          *
 648          * @param string $actor
 649          * @param array  $tags
 650          *
 651          * @return array with receivers (user id)
 652          * @throws \Exception
 653          */
 654         private static function getReceiverForActor($actor, $tags, $receivers)
 655         {
 656                 $basecondition = ['rel' => [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER],
 657                         'network' => Protocol::FEDERATED, 'archive' => false, 'pending' => false];
 658
 659                 $condition = DBA::mergeConditions($basecondition, ['nurl' => Strings::normaliseLink($actor)]);
 660                 $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
 661                 while ($contact = DBA::fetch($contacts)) {
 662                         if (empty($receivers['uid:' . $contact['uid']]) && self::isValidReceiverForActor($contact, $actor, $tags)) {
 663                                 $receivers['uid:' . $contact['uid']] = ['uid' => $contact['uid'], 'type' => self::TARGET_FOLLOWER];
 664                         }
 665                 }
 666                 DBA::close($contacts);
 667
 668                 // The queries are split because of performance issues
 669                 $condition = DBA::mergeConditions($basecondition, ["`alias` IN (?, ?)", Strings::normaliseLink($actor), $actor]);
 670                 $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
 671                 while ($contact = DBA::fetch($contacts)) {
 672                         if (empty($receivers['uid:' . $contact['uid']]) && self::isValidReceiverForActor($contact, $actor, $tags)) {
 673                                 $receivers['uid:' . $contact['uid']] = ['uid' => $contact['uid'], 'type' => self::TARGET_FOLLOWER];
 674                         }
 675                 }
 676                 DBA::close($contacts);
 677                 return $receivers;
 678         }
 679
 680         /**
 681          * Tests if the contact is a valid receiver for this actor
 682          *
 683          * @param array  $contact
 684          * @param string $actor
 685          * @param array  $tags
 686          *
 687          * @return bool with receivers (user id)
 688          * @throws \Exception
 689          */
 690         private static function isValidReceiverForActor($contact, $actor, $tags)
 691         {
 692                 // Public contacts are no valid receiver
 693                 if ($contact['uid'] == 0) {
 694                         return false;
 695                 }
 696
 697                 // Are we following the contact? Then this is a valid receiver
 698                 if (in_array($contact['rel'], [Contact::SHARING, Contact::FRIEND])) {
 699                         return true;
 700                 }
 701
 702                 // When the possible receiver isn't a community, then it is no valid receiver
 703                 $owner = User::getOwnerDataById($contact['uid']);
 704                 if (empty($owner) || ($owner['contact-type'] != Contact::TYPE_COMMUNITY)) {
 705                         return false;
 706                 }
 707
 708                 // Is the community account tagged?
 709                 foreach ($tags as $tag) {
 710                         if ($tag['type'] != 'Mention') {
 711                                 continue;
 712                         }
 713
 714                         if ($tag['href'] == $owner['url']) {
 715                                 return true;
 716                         }
 717                 }
 718
 719                 return false;
 720         }
 721
 722         /**
 723          * Switches existing contacts to ActivityPub
 724          *
 725          * @param integer $cid Contact ID
 726          * @param integer $uid User ID
 727          * @param string  $url Profile URL
 728          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 729          * @throws \ImagickException
 730          */
 731         public static function switchContact($cid, $uid, $url)
 732         {
 733                 if (DBA::exists('contact', ['id' => $cid, 'network' => Protocol::ACTIVITYPUB])) {
 734                         Logger::info('Contact is already ActivityPub', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
 735                         return;
 736                 }
 737
 738                 if (Contact::updateFromProbe($cid)) {
 739                         Logger::info('Update was successful', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
 740                 }
 741
 742                 // Send a new follow request to be sure that the connection still exists
 743                 if (($uid != 0) && DBA::exists('contact', ['id' => $cid, 'rel' => [Contact::SHARING, Contact::FRIEND], 'network' => Protocol::ACTIVITYPUB])) {
 744                         Logger::info('Contact had been switched to ActivityPub. Sending a new follow request.', ['uid' => $uid, 'url' => $url]);
 745                         ActivityPub\Transmitter::sendActivity('Follow', $url, $uid);
 746                 }
 747         }
 748
 749         /**
 750          *
 751          *
 752          * @param $receivers
 753          * @param $actor
 754          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 755          * @throws \ImagickException
 756          */
 757         private static function switchContacts($receivers, $actor)
 758         {
 759                 if (empty($actor)) {
 760                         return;
 761                 }
 762
 763                 foreach ($receivers as $receiver) {
 764                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver['uid'], 'network' => Protocol::OSTATUS, 'nurl' => Strings::normaliseLink($actor)]);
 765                         if (DBA::isResult($contact)) {
 766                                 self::switchContact($contact['id'], $receiver['uid'], $actor);
 767                         }
 768
 769                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver['uid'], 'network' => Protocol::OSTATUS, 'alias' => [Strings::normaliseLink($actor), $actor]]);
 770                         if (DBA::isResult($contact)) {
 771                                 self::switchContact($contact['id'], $receiver['uid'], $actor);
 772                         }
 773                 }
 774         }
 775
 776         /**
 777          *
 778          *
 779          * @param       $object_data
 780          * @param array $activity
 781          *
 782          * @return mixed
 783          */
 784         private static function addActivityFields($object_data, $activity)
 785         {
 786                 if (!empty($activity['published']) && empty($object_data['published'])) {
 787                         $object_data['published'] = JsonLD::fetchElement($activity, 'as:published', '@value');
 788                 }
 789
 790                 if (!empty($activity['diaspora:guid']) && empty($object_data['diaspora:guid'])) {
 791                         $object_data['diaspora:guid'] = JsonLD::fetchElement($activity, 'diaspora:guid', '@value');
 792                 }
 793
 794                 $object_data['service'] = JsonLD::fetchElement($activity, 'as:instrument', 'as:name', '@type', 'as:Service');
 795                 $object_data['service'] = JsonLD::fetchElement($object_data, 'service', '@value');
 796
 797                 if (!empty($object_data['object_id'])) {
 798                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
 799                         $objectId = Item::getURIByLink($object_data['object_id']);
 800                         if (!empty($objectId) && ($object_data['object_id'] != $objectId)) {
 801                                 Logger::notice('Fix wrong object-id', ['received' => $object_data['object_id'], 'correct' => $objectId]);
 802                                 $object_data['object_id'] = $objectId;
 803                         }
 804                 }
 805
 806                 return $object_data;
 807         }
 808
 809         /**
 810          * Fetches the object data from external ressources if needed
 811          *
 812          * @param string  $object_id    Object ID of the the provided object
 813          * @param array   $object       The provided object array
 814          * @param boolean $trust_source Do we trust the provided object?
 815          * @param integer $uid          User ID for the signature that we use to fetch data
 816          *
 817          * @return array|false with trusted and valid object data
 818          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 819          * @throws \ImagickException
 820          */
 821         private static function fetchObject(string $object_id, array $object = [], bool $trust_source = false, int $uid = 0)
 822         {
 823                 // By fetching the type we check if the object is complete.
 824                 $type = JsonLD::fetchElement($object, '@type');
 825
 826                 if (!$trust_source || empty($type)) {
 827                         $data = ActivityPub::fetchContent($object_id, $uid);
 828                         if (!empty($data)) {
 829                                 $object = JsonLD::compact($data);
 830                                 Logger::log('Fetched content for ' . $object_id, Logger::DEBUG);
 831                         } else {
 832                                 Logger::log('Empty content for ' . $object_id . ', check if content is available locally.', Logger::DEBUG);
 833
 834                                 $item = Item::selectFirst([], ['uri' => $object_id]);
 835                                 if (!DBA::isResult($item)) {
 836                                         Logger::log('Object with url ' . $object_id . ' was not found locally.', Logger::DEBUG);
 837                                         return false;
 838                                 }
 839                                 Logger::log('Using already stored item for url ' . $object_id, Logger::DEBUG);
 840                                 $data = ActivityPub\Transmitter::createNote($item);
 841                                 $object = JsonLD::compact($data);
 842                         }
 843
 844                         $id = JsonLD::fetchElement($object, '@id');
 845                         if (empty($id)) {
 846                                 Logger::info('Empty id');
 847                                 return false;
 848                         }
 849
 850                         if ($id != $object_id) {
 851                                 Logger::info('Fetched id differs from provided id', ['provided' => $object_id, 'fetched' => $id]);
 852                                 return false;
 853                         }
 854                 } else {
 855                         Logger::log('Using original object for url ' . $object_id, Logger::DEBUG);
 856                 }
 857
 858                 $type = JsonLD::fetchElement($object, '@type');
 859                 if (empty($type)) {
 860                         Logger::info('Empty type');
 861                         return false;
 862                 }
 863
 864                 // We currently don't handle 'pt:CacheFile', but with this step we avoid logging
 865                 if (in_array($type, self::CONTENT_TYPES) || ($type == 'pt:CacheFile')) {
 866                         $object_data = self::processObject($object);
 867
 868                         if (!empty($data)) {
 869                                 $object_data['raw'] = json_encode($data);
 870                         }
 871                         return $object_data;
 872                 }
 873
 874                 if ($type == 'as:Announce') {
 875                         $object_id = JsonLD::fetchElement($object, 'object', '@id');
 876                         if (empty($object_id) || !is_string($object_id)) {
 877                                 return false;
 878                         }
 879                         return self::fetchObject($object_id, [], false, $uid);
 880                 }
 881
 882                 Logger::log('Unhandled object type: ' . $type, Logger::DEBUG);
 883                 return false;
 884         }
 885
 886         /**
 887          * Convert tags from JSON-LD format into a simplified format
 888          *
 889          * @param array $tags Tags in JSON-LD format
 890          *
 891          * @return array with tags in a simplified format
 892          */
 893         private static function processTags(array $tags)
 894         {
 895                 $taglist = [];
 896
 897                 foreach ($tags as $tag) {
 898                         if (empty($tag)) {
 899                                 continue;
 900                         }
 901
 902                         $element = ['type' => str_replace('as:', '', JsonLD::fetchElement($tag, '@type')),
 903                                 'href' => JsonLD::fetchElement($tag, 'as:href', '@id'),
 904                                 'name' => JsonLD::fetchElement($tag, 'as:name', '@value')];
 905
 906                         if (empty($element['type'])) {
 907                                 continue;
 908                         }
 909
 910                         if (empty($element['href'])) {
 911                                 $element['href'] = $element['name'];
 912                         }
 913
 914                         $taglist[] = $element;
 915                 }
 916                 return $taglist;
 917         }
 918
 919         /**
 920          * Convert emojis from JSON-LD format into a simplified format
 921          *
 922          * @param array $emojis
 923          * @return array with emojis in a simplified format
 924          */
 925         private static function processEmojis(array $emojis)
 926         {
 927                 $emojilist = [];
 928
 929                 foreach ($emojis as $emoji) {
 930                         if (empty($emoji) || (JsonLD::fetchElement($emoji, '@type') != 'toot:Emoji') || empty($emoji['as:icon'])) {
 931                                 continue;
 932                         }
 933
 934                         $url = JsonLD::fetchElement($emoji['as:icon'], 'as:url', '@id');
 935                         $element = ['name' => JsonLD::fetchElement($emoji, 'as:name', '@value'),
 936                                 'href' => $url];
 937
 938                         $emojilist[] = $element;
 939                 }
 940
 941                 return $emojilist;
 942         }
 943
 944         /**
 945          * Convert attachments from JSON-LD format into a simplified format
 946          *
 947          * @param array $attachments Attachments in JSON-LD format
 948          *
 949          * @return array Attachments in a simplified format
 950          */
 951         private static function processAttachments(array $attachments)
 952         {
 953                 $attachlist = [];
 954
 955                 // Removes empty values
 956                 $attachments = array_filter($attachments);
 957
 958                 foreach ($attachments as $attachment) {
 959                         switch (JsonLD::fetchElement($attachment, '@type')) {
 960                                 case 'as:Page':
 961                                         $pageUrl = null;
 962                                         $pageImage = null;
 963
 964                                         $urls = JsonLD::fetchElementArray($attachment, 'as:url');
 965                                         foreach ($urls as $url) {
 966                                                 // Single scalar URL case
 967                                                 if (is_string($url)) {
 968                                                         $pageUrl = $url;
 969                                                         continue;
 970                                                 }
 971
 972                                                 $href = JsonLD::fetchElement($url, 'as:href', '@id');
 973                                                 $mediaType = JsonLD::fetchElement($url, 'as:mediaType', '@value');
 974                                                 if (Strings::startsWith($mediaType, 'image')) {
 975                                                         $pageImage = $href;
 976                                                 } else {
 977                                                         $pageUrl = $href;
 978                                                 }
 979                                         }
 980
 981                                         $attachlist[] = [
 982                                                 'type'  => 'link',
 983                                                 'title' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
 984                                                 'desc'  => JsonLD::fetchElement($attachment, 'as:summary', '@value'),
 985                                                 'url'   => $pageUrl,
 986                                                 'image' => $pageImage,
 987                                         ];
 988                                         break;
 989                                 case 'as:Link':
 990                                         $attachlist[] = [
 991                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
 992                                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType', '@value'),
 993                                                 'name' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
 994                                                 'url' => JsonLD::fetchElement($attachment, 'as:href', '@id')
 995                                         ];
 996                                         break;
 997                                 case 'as:Image':
 998                                         $mediaType = JsonLD::fetchElement($attachment, 'as:mediaType', '@value');
 999                                         $imageFullUrl = JsonLD::fetchElement($attachment, 'as:url', '@id');
1000                                         $imagePreviewUrl = null;
1001                                         // Multiple URLs?
1002                                         if (!$imageFullUrl && ($urls = JsonLD::fetchElementArray($attachment, 'as:url'))) {
1003                                                 $imageVariants = [];
1004                                                 $previewVariants = [];
1005                                                 foreach ($urls as $url) {
1006                                                         // Scalar URL, no discrimination possible
1007                                                         if (is_string($url)) {
1008                                                                 $imageFullUrl = $url;
1009                                                                 continue;
1010                                                         }
1011
1012                                                         // Not sure what to do with a different Link media type than the base Image, we skip
1013                                                         if ($mediaType != JsonLD::fetchElement($url, 'as:mediaType', '@value')) {
1014                                                                 continue;
1015                                                         }
1016
1017                                                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1018
1019                                                         // Default URL choice if no discriminating width is provided
1020                                                         $imageFullUrl = $href ?? $imageFullUrl;
1021
1022                                                         $width = intval(JsonLD::fetchElement($url, 'as:width', '@value') ?? 1);
1023
1024                                                         if ($href && $width) {
1025                                                                 $imageVariants[$width] = $href;
1026                                                                 // 632 is the ideal width for full screen frio posts, we compute the absolute distance to it
1027                                                                 $previewVariants[abs(632 - $width)] = $href;
1028                                                         }
1029                                                 }
1030
1031                                                 if ($imageVariants) {
1032                                                         // Taking the maximum size image
1033                                                         ksort($imageVariants);
1034                                                         $imageFullUrl = array_pop($imageVariants);
1035
1036                                                         // Taking the minimum number distance to the target distance
1037                                                         ksort($previewVariants);
1038                                                         $imagePreviewUrl = array_shift($previewVariants);
1039                                                 }
1040
1041                                                 unset($imageVariants);
1042                                                 unset($previewVariants);
1043                                         }
1044
1045                                         $attachlist[] = [
1046                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1047                                                 'mediaType' => $mediaType,
1048                                                 'name'  => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1049                                                 'url'   => $imageFullUrl,
1050                                                 'image' => $imagePreviewUrl !== $imageFullUrl ? $imagePreviewUrl : null,
1051                                         ];
1052                                         break;
1053                                 default:
1054                                         $attachlist[] = [
1055                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1056                                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType', '@value'),
1057                                                 'name' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1058                                                 'url' => JsonLD::fetchElement($attachment, 'as:url', '@id')
1059                                         ];
1060                         }
1061                 }
1062
1063                 return $attachlist;
1064         }
1065
1066         /**
1067          * Fetch the original source or content with the "language" Markdown or HTML
1068          *
1069          * @param array $object
1070          * @param array $object_data
1071          *
1072          * @return array
1073          * @throws \Exception
1074          */
1075         private static function getSource($object, $object_data)
1076         {
1077                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/bbcode');
1078                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1079                 if (!empty($object_data['source'])) {
1080                         return $object_data;
1081                 }
1082
1083                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/markdown');
1084                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1085                 if (!empty($object_data['source'])) {
1086                         $object_data['source'] = Markdown::toBBCode($object_data['source']);
1087                         return $object_data;
1088                 }
1089
1090                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/html');
1091                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1092                 if (!empty($object_data['source'])) {
1093                         $object_data['source'] = HTML::toBBCode($object_data['source']);
1094                         return $object_data;
1095                 }
1096
1097                 return $object_data;
1098         }
1099
1100         /**
1101          * Check if the "as:url" element is an array with multiple links
1102          * This is the case with audio and video posts.
1103          * Then the links are added as attachments
1104          *
1105          * @param array $object      The raw object
1106          * @param array $object_data The parsed object data for later processing
1107          * @return array the object data
1108          */
1109         private static function processAttachmentUrls(array $object, array $object_data) {
1110                 // Check if this is some url with multiple links
1111                 if (empty($object['as:url'])) {
1112                         return $object_data;
1113                 }
1114
1115                 $urls = $object['as:url'];
1116                 $keys = array_keys($urls);
1117                 if (!is_numeric(array_pop($keys))) {
1118                         return $object_data;
1119                 }
1120
1121                 $attachments = [];
1122
1123                 foreach ($urls as $url) {
1124                         if (empty($url['@type']) || ($url['@type'] != 'as:Link')) {
1125                                 continue;
1126                         }
1127
1128                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1129                         if (empty($href)) {
1130                                 continue;
1131                         }
1132
1133                         $mediatype = JsonLD::fetchElement($url, 'as:mediaType');
1134                         if (empty($mediatype)) {
1135                                 continue;
1136                         }
1137
1138                         if ($mediatype == 'text/html') {
1139                                 $object_data['alternate-url'] = $href;
1140                         }
1141
1142                         $filetype = strtolower(substr($mediatype, 0, strpos($mediatype, '/')));
1143
1144                         if ($filetype == 'audio') {
1145                                 $attachments[$filetype] = ['type' => $mediatype, 'url' => $href];
1146                         } elseif ($filetype == 'video') {
1147                                 $height = (int)JsonLD::fetchElement($url, 'as:height', '@value');
1148
1149                                 // We save bandwidth by using a moderate height
1150                                 // Peertube normally uses these heights: 240, 360, 480, 720, 1080
1151                                 if (!empty($attachments[$filetype]['height']) &&
1152                                         (($height > 480) || $height < $attachments[$filetype]['height'])) {
1153                                         continue;
1154                                 }
1155
1156                                 $attachments[$filetype] = ['type' => $mediatype, 'url' => $href, 'height' => $height];
1157                         }
1158                 }
1159
1160                 foreach ($attachments as $type => $attachment) {
1161                         $object_data['attachments'][] = ['type' => $type,
1162                                 'mediaType' => $attachment['type'],
1163                                 'name' => '',
1164                                 'url' => $attachment['url']];
1165                 }
1166                 return $object_data;
1167         }
1168
1169         /**
1170          * Fetches data from the object part of an activity
1171          *
1172          * @param array $object
1173          *
1174          * @return array
1175          * @throws \Exception
1176          */
1177         private static function processObject($object)
1178         {
1179                 if (!JsonLD::fetchElement($object, '@id')) {
1180                         return false;
1181                 }
1182
1183                 $object_data = [];
1184                 $object_data['object_type'] = JsonLD::fetchElement($object, '@type');
1185                 $object_data['id'] = JsonLD::fetchElement($object, '@id');
1186                 $object_data['reply-to-id'] = JsonLD::fetchElement($object, 'as:inReplyTo', '@id');
1187
1188                 // An empty "id" field is translated to "./" by the compactor, so we have to check for this content
1189                 if (empty($object_data['reply-to-id']) || ($object_data['reply-to-id'] == './')) {
1190                         $object_data['reply-to-id'] = $object_data['id'];
1191                 } else {
1192                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
1193                         $replyToId = Item::getURIByLink($object_data['reply-to-id']);
1194                         if (!empty($replyToId) && ($object_data['reply-to-id'] != $replyToId)) {
1195                                 Logger::notice('Fix wrong reply-to', ['received' => $object_data['reply-to-id'], 'correct' => $replyToId]);
1196                                 $object_data['reply-to-id'] = $replyToId;
1197                         }
1198                 }
1199
1200                 $object_data['published'] = JsonLD::fetchElement($object, 'as:published', '@value');
1201                 $object_data['updated'] = JsonLD::fetchElement($object, 'as:updated', '@value');
1202
1203                 if (empty($object_data['updated'])) {
1204                         $object_data['updated'] = $object_data['published'];
1205                 }
1206
1207                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
1208                         $object_data['published'] = $object_data['updated'];
1209                 }
1210
1211                 $actor = JsonLD::fetchElement($object, 'as:attributedTo', '@id');
1212                 if (empty($actor)) {
1213                         $actor = JsonLD::fetchElement($object, 'as:actor', '@id');
1214                 }
1215
1216                 $location = JsonLD::fetchElement($object, 'as:location', 'as:name', '@type', 'as:Place');
1217                 $location = JsonLD::fetchElement($location, 'location', '@value');
1218                 if ($location) {
1219                         // Some AP software allow formatted text in post location, so we run all the text converters we have to boil
1220                         // down to HTML and then finally format to plaintext.
1221                         $location = Markdown::convert($location);
1222                         $location = BBCode::convert($location);
1223                         $location = HTML::toPlaintext($location);
1224                 }
1225
1226                 $object_data['sc:identifier'] = JsonLD::fetchElement($object, 'sc:identifier', '@value');
1227                 $object_data['diaspora:guid'] = JsonLD::fetchElement($object, 'diaspora:guid', '@value');
1228                 $object_data['diaspora:comment'] = JsonLD::fetchElement($object, 'diaspora:comment', '@value');
1229                 $object_data['diaspora:like'] = JsonLD::fetchElement($object, 'diaspora:like', '@value');
1230                 $object_data['actor'] = $object_data['author'] = $actor;
1231                 $object_data['context'] = JsonLD::fetchElement($object, 'as:context', '@id');
1232                 $object_data['conversation'] = JsonLD::fetchElement($object, 'ostatus:conversation', '@id');
1233                 $object_data['sensitive'] = JsonLD::fetchElement($object, 'as:sensitive');
1234                 $object_data['name'] = JsonLD::fetchElement($object, 'as:name', '@value');
1235                 $object_data['summary'] = JsonLD::fetchElement($object, 'as:summary', '@value');
1236                 $object_data['content'] = JsonLD::fetchElement($object, 'as:content', '@value');
1237                 $object_data = self::getSource($object, $object_data);
1238                 $object_data['start-time'] = JsonLD::fetchElement($object, 'as:startTime', '@value');
1239                 $object_data['end-time'] = JsonLD::fetchElement($object, 'as:endTime', '@value');
1240                 $object_data['location'] = $location;
1241                 $object_data['latitude'] = JsonLD::fetchElement($object, 'as:location', 'as:latitude', '@type', 'as:Place');
1242                 $object_data['latitude'] = JsonLD::fetchElement($object_data, 'latitude', '@value');
1243                 $object_data['longitude'] = JsonLD::fetchElement($object, 'as:location', 'as:longitude', '@type', 'as:Place');
1244                 $object_data['longitude'] = JsonLD::fetchElement($object_data, 'longitude', '@value');
1245                 $object_data['attachments'] = self::processAttachments(JsonLD::fetchElementArray($object, 'as:attachment') ?? []);
1246                 $object_data['tags'] = self::processTags(JsonLD::fetchElementArray($object, 'as:tag') ?? []);
1247                 $object_data['emojis'] = self::processEmojis(JsonLD::fetchElementArray($object, 'as:tag', 'toot:Emoji') ?? []);
1248                 $object_data['generator'] = JsonLD::fetchElement($object, 'as:generator', 'as:name', '@type', 'as:Application');
1249                 $object_data['generator'] = JsonLD::fetchElement($object_data, 'generator', '@value');
1250                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'as:url', '@id');
1251
1252                 // Special treatment for Hubzilla links
1253                 if (is_array($object_data['alternate-url'])) {
1254                         $object_data['alternate-url'] = JsonLD::fetchElement($object_data['alternate-url'], 'as:href', '@id');
1255
1256                         if (!is_string($object_data['alternate-url'])) {
1257                                 $object_data['alternate-url'] = JsonLD::fetchElement($object['as:url'], 'as:href', '@id');
1258                         }
1259                 }
1260
1261                 if (in_array($object_data['object_type'], ['as:Audio', 'as:Video'])) {
1262                         $object_data = self::processAttachmentUrls($object, $object_data);
1263                 }
1264
1265                 $receiverdata = self::getReceivers($object, $object_data['actor'], $object_data['tags'], true);
1266                 $receivers = [];
1267                 foreach ($receiverdata as $key => $data) {
1268                         $receivers[$key] = $data['uid'];
1269                 }
1270
1271                 $object_data['receiver'] = $receivers;
1272
1273                 $object_data['unlisted'] = in_array(-1, $object_data['receiver']);
1274                 unset($object_data['receiver']['uid:-1']);
1275
1276                 // Common object data:
1277
1278                 // Unhandled
1279                 // @context, type, actor, signature, mediaType, duration, replies, icon
1280
1281                 // Also missing: (Defined in the standard, but currently unused)
1282                 // audience, preview, endTime, startTime, image
1283
1284                 // Data in Notes:
1285
1286                 // Unhandled
1287                 // contentMap, announcement_count, announcements, context_id, likes, like_count
1288                 // inReplyToStatusId, shares, quoteUrl, statusnetConversationId
1289
1290                 // Data in video:
1291
1292                 // To-Do?
1293                 // category, licence, language, commentsEnabled
1294
1295                 // Unhandled
1296                 // views, waitTranscoding, state, support, subtitleLanguage
1297                 // likes, dislikes, shares, comments
1298
1299                 return $object_data;
1300         }
1301 }