src/Protocol/ActivityPub/Receiver.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2010-2022, the Friendica project
   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\Core\System;
  31 use Friendica\DI;
  32 use Friendica\Model\Contact;
  33 use Friendica\Model\APContact;
  34 use Friendica\Model\Item;
  35 use Friendica\Model\Post;
  36 use Friendica\Model\User;
  37 use Friendica\Protocol\Activity;
  38 use Friendica\Protocol\ActivityPub;
  39 use Friendica\Util\HTTPSignature;
  40 use Friendica\Util\JsonLD;
  41 use Friendica\Util\LDSignature;
  42 use Friendica\Util\Strings;
  43
  44 /**
  45  * ActivityPub Receiver Protocol class
  46  *
  47  * To-Do:
  48  * @todo Undo Announce
  49  *
  50  * Check what this is meant to do:
  51  * - Add
  52  * - Block
  53  * - Flag
  54  * - Remove
  55  * - Undo Block
  56  */
  57 class Receiver
  58 {
  59         const PUBLIC_COLLECTION = 'as:Public';
  60         const ACCOUNT_TYPES = ['as:Person', 'as:Organization', 'as:Service', 'as:Group', 'as:Application'];
  61         const CONTENT_TYPES = ['as:Note', 'as:Article', 'as:Video', 'as:Image', 'as:Event', 'as:Audio', 'as:Page', 'as:Question'];
  62         const ACTIVITY_TYPES = ['as:Like', 'as:Dislike', 'as:Accept', 'as:Reject', 'as:TentativeAccept'];
  63
  64         const TARGET_UNKNOWN = 0;
  65         const TARGET_TO = 1;
  66         const TARGET_CC = 2;
  67         const TARGET_BTO = 3;
  68         const TARGET_BCC = 4;
  69         const TARGET_FOLLOWER = 5;
  70         const TARGET_ANSWER = 6;
  71         const TARGET_GLOBAL = 7;
  72
  73         const COMPLETION_NONE    = 0;
  74         const COMPLETION_ANNOUCE = 1;
  75         const COMPLETION_RELAY   = 2;
  76         const COMPLETION_MANUAL  = 3;
  77         const COMPLETION_AUTO    = 4;
  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                 $activity = json_decode($body, true);
  90                 if (empty($activity)) {
  91                         Logger::warning('Invalid body.');
  92                         return;
  93                 }
  94
  95                 $ldactivity = JsonLD::compact($activity);
  96
  97                 $actor = JsonLD::fetchElement($ldactivity, 'as:actor', '@id');
  98
  99                 $apcontact = APContact::getByURL($actor);
 100                 if (empty($apcontact)) {
 101                         Logger::notice('Unable to retrieve AP contact for actor - message is discarded', ['actor' => $actor]);
 102                         return;
 103                 } elseif ($apcontact['type'] == 'Application' && $apcontact['nick'] == 'relay') {
 104                         self::processRelayPost($ldactivity, $actor);
 105                         return;
 106                 } else {
 107                         APContact::unmarkForArchival($apcontact);
 108                 }
 109
 110                 $http_signer = HTTPSignature::getSigner($body, $header);
 111                 if ($http_signer === false) {
 112                         Logger::warning('Invalid HTTP signature, message will be discarded.');
 113                         return;
 114                 } elseif (empty($http_signer)) {
 115                         Logger::info('Signer is a tombstone. The message will be discarded, the signer account is deleted.');
 116                         return;
 117                 } else {
 118                         Logger::info('Valid HTTP signature', ['signer' => $http_signer]);
 119                 }
 120
 121                 $signer = [$http_signer];
 122
 123                 Logger::info('Message for user ' . $uid . ' is from actor ' . $actor);
 124
 125                 if (LDSignature::isSigned($activity)) {
 126                         $ld_signer = LDSignature::getSigner($activity);
 127                         if (empty($ld_signer)) {
 128                                 Logger::info('Invalid JSON-LD signature from ' . $actor);
 129                         } elseif ($ld_signer != $http_signer) {
 130                                 $signer[] = $ld_signer;
 131                         }
 132                         if (!empty($ld_signer && ($actor == $http_signer))) {
 133                                 Logger::info('The HTTP and the JSON-LD signature belong to ' . $ld_signer);
 134                                 $trust_source = true;
 135                         } elseif (!empty($ld_signer)) {
 136                                 Logger::info('JSON-LD signature is signed by ' . $ld_signer);
 137                                 $trust_source = true;
 138                         } elseif ($actor == $http_signer) {
 139                                 Logger::info('Bad JSON-LD signature, but HTTP signer fits the actor.');
 140                                 $trust_source = true;
 141                         } else {
 142                                 Logger::info('Invalid JSON-LD signature and the HTTP signer is different.');
 143                                 $trust_source = false;
 144                         }
 145                 } elseif ($actor == $http_signer) {
 146                         Logger::info('Trusting post without JSON-LD signature, The actor fits the HTTP signer.');
 147                         $trust_source = true;
 148                 } else {
 149                         Logger::info('No JSON-LD signature, different actor.');
 150                         $trust_source = false;
 151                 }
 152
 153                 self::processActivity($ldactivity, $body, $uid, $trust_source, true, $signer);
 154         }
 155
 156         /**
 157          * Process incoming posts from relays
 158          *
 159          * @param array  $activity
 160          * @param string $actor
 161          * @return void
 162          */
 163         private static function processRelayPost(array $activity, string $actor)
 164         {
 165                 $type = JsonLD::fetchElement($activity, '@type');
 166                 if (!$type) {
 167                         Logger::info('Empty type', ['activity' => $activity]);
 168                         return;
 169                 }
 170
 171                 if ($type != 'as:Announce') {
 172                         Logger::info('Not an announcement', ['activity' => $activity]);
 173                         return;
 174                 }
 175
 176                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 177                 if (empty($object_id)) {
 178                         Logger::info('No object id found', ['activity' => $activity]);
 179                         return;
 180                 }
 181
 182                 $contact = Contact::getByURL($actor);
 183                 if (empty($contact)) {
 184                         Logger::info('Relay contact not found', ['actor' => $actor]);
 185                         return;
 186                 }
 187
 188                 if (!in_array($contact['rel'], [Contact::SHARING, Contact::FRIEND])) {
 189                         Logger::notice('Relay is no sharer', ['actor' => $actor]);
 190                         return;
 191                 }
 192
 193                 Logger::info('Got relayed message id', ['id' => $object_id]);
 194
 195                 $item_id = Item::searchByLink($object_id);
 196                 if ($item_id) {
 197                         Logger::info('Relayed message already exists', ['id' => $object_id, 'item' => $item_id]);
 198                         return;
 199                 }
 200
 201                 $id = Processor::fetchMissingActivity($object_id, [], $actor, self::COMPLETION_RELAY);
 202                 if (empty($id)) {
 203                         Logger::notice('Relayed message had not been fetched', ['id' => $object_id]);
 204                         return;
 205                 }
 206
 207                 $item_id = Item::searchByLink($object_id);
 208                 if ($item_id) {
 209                         Logger::info('Relayed message had been fetched and stored', ['id' => $object_id, 'item' => $item_id]);
 210                 } else {
 211                         Logger::notice('Relayed message had not been stored', ['id' => $object_id]);
 212                 }
 213         }
 214
 215         /**
 216          * Fetches the object type for a given object id
 217          *
 218          * @param array   $activity
 219          * @param string  $object_id Object ID of the the provided object
 220          * @param integer $uid       User ID
 221          *
 222          * @return string with object type
 223          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 224          * @throws \ImagickException
 225          */
 226         private static function fetchObjectType($activity, $object_id, $uid = 0)
 227         {
 228                 if (!empty($activity['as:object'])) {
 229                         $object_type = JsonLD::fetchElement($activity['as:object'], '@type');
 230                         if (!empty($object_type)) {
 231                                 return $object_type;
 232                         }
 233                 }
 234
 235                 if (Post::exists(['uri' => $object_id, 'gravity' => [GRAVITY_PARENT, GRAVITY_COMMENT]])) {
 236                         // We just assume "note" since it doesn't make a difference for the further processing
 237                         return 'as:Note';
 238                 }
 239
 240                 $profile = APContact::getByURL($object_id);
 241                 if (!empty($profile['type'])) {
 242                         APContact::unmarkForArchival($profile);
 243                         return 'as:' . $profile['type'];
 244                 }
 245
 246                 $data = ActivityPub::fetchContent($object_id, $uid);
 247                 if (!empty($data)) {
 248                         $object = JsonLD::compact($data);
 249                         $type = JsonLD::fetchElement($object, '@type');
 250                         if (!empty($type)) {
 251                                 return $type;
 252                         }
 253                 }
 254
 255                 return null;
 256         }
 257
 258         /**
 259          * Prepare the object array
 260          *
 261          * @param array   $activity     Array with activity data
 262          * @param integer $uid          User ID
 263          * @param boolean $push         Message had been pushed to our system
 264          * @param boolean $trust_source Do we trust the source?
 265          *
 266          * @return array with object data
 267          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 268          * @throws \ImagickException
 269          */
 270         public static function prepareObjectData($activity, $uid, $push, &$trust_source)
 271         {
 272                 $id = JsonLD::fetchElement($activity, '@id');
 273                 if (!empty($id) && !$trust_source) {
 274                         $fetch_uid = $uid ?: self::getBestUserForActivity($activity);
 275
 276                         $fetched_activity = ActivityPub::fetchContent($id, $fetch_uid);
 277                         if (!empty($fetched_activity)) {
 278                                 $object = JsonLD::compact($fetched_activity);
 279                                 $fetched_id = JsonLD::fetchElement($object, '@id');
 280                                 if ($fetched_id == $id) {
 281                                         Logger::info('Activity had been fetched successfully', ['id' => $id]);
 282                                         $trust_source = true;
 283                                         $activity = $object;
 284                                 } else {
 285                                         Logger::info('Activity id is not equal', ['id' => $id, 'fetched' => $fetched_id]);
 286                                 }
 287                         } else {
 288                                 Logger::info('Activity could not been fetched', ['id' => $id]);
 289                         }
 290                 }
 291
 292                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 293                 if (empty($actor)) {
 294                         Logger::info('Empty actor', ['activity' => $activity]);
 295                         return [];
 296                 }
 297
 298                 $type = JsonLD::fetchElement($activity, '@type');
 299
 300                 // Fetch all receivers from to, cc, bto and bcc
 301                 $receiverdata = self::getReceivers($activity, $actor);
 302                 $receivers = $reception_types = [];
 303                 foreach ($receiverdata as $key => $data) {
 304                         $receivers[$key] = $data['uid'];
 305                         $reception_types[$data['uid']] = $data['type'] ?? self::TARGET_UNKNOWN;
 306                 }
 307
 308                 $urls = self::getReceiverURL($activity);
 309
 310                 // When it is a delivery to a personal inbox we add that user to the receivers
 311                 if (!empty($uid)) {
 312                         $additional = [$uid => $uid];
 313                         $receivers = array_replace($receivers, $additional);
 314                         if (empty($activity['thread-completion']) && (empty($reception_types[$uid]) || in_array($reception_types[$uid], [self::TARGET_UNKNOWN, self::TARGET_FOLLOWER, self::TARGET_ANSWER, self::TARGET_GLOBAL]))) {
 315                                 $reception_types[$uid] = self::TARGET_BCC;
 316                                 $owner = User::getOwnerDataById($uid);
 317                                 if (!empty($owner['url'])) {
 318                                         $urls['as:bcc'][] = $owner['url'];
 319                                 }
 320                         }
 321                 }
 322
 323                 // We possibly need some user to fetch private content,
 324                 // so we fetch one out of the receivers if no uid is provided.
 325                 $fetch_uid = $uid ?: self::getBestUserForActivity($activity);
 326
 327                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 328                 if (empty($object_id)) {
 329                         Logger::info('No object found');
 330                         return [];
 331                 }
 332
 333                 if (!is_string($object_id)) {
 334                         Logger::info('Invalid object id', ['object' => $object_id]);
 335                         return [];
 336                 }
 337
 338                 $object_type = self::fetchObjectType($activity, $object_id, $fetch_uid);
 339
 340                 // Fetch the activity on Lemmy "Announce" messages (announces of activities)
 341                 if (($type == 'as:Announce') && in_array($object_type, array_merge(self::ACTIVITY_TYPES, ['as:Delete', 'as:Undo', 'as:Update']))) {
 342                         $data = ActivityPub::fetchContent($object_id, $fetch_uid);
 343                         if (!empty($data)) {
 344                                 $type = $object_type;
 345                                 $activity = JsonLD::compact($data);
 346
 347                                 // Some variables need to be refetched since the activity changed
 348                                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 349                                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 350                                 $object_type = self::fetchObjectType($activity, $object_id, $fetch_uid);
 351                         }
 352                 }
 353
 354                 // Any activities on account types must not be altered
 355                 if (in_array($object_type, self::ACCOUNT_TYPES)) {
 356                         $object_data = [];
 357                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 358                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 359                         $object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor', '@id');
 360                         $object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
 361                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 362                         $object_data['push'] = $push;
 363                 } elseif (in_array($type, ['as:Create', 'as:Update', 'as:Announce', 'as:Invite']) || strpos($type, '#emojiReaction')) {
 364                         // Fetch the content only on activities where this matters
 365                         // We can receive "#emojiReaction" when fetching content from Hubzilla systems
 366                         // Always fetch on "Announce"
 367                         $object_data = self::fetchObject($object_id, $activity['as:object'], $trust_source && ($type != 'as:Announce'), $fetch_uid);
 368                         if (empty($object_data)) {
 369                                 Logger::info("Object data couldn't be processed");
 370                                 return [];
 371                         }
 372
 373                         $object_data['object_id'] = $object_id;
 374
 375                         if ($type == 'as:Announce') {
 376                                 $object_data['push'] = false;
 377                         } else {
 378                                 $object_data['push'] = $push;
 379                         }
 380
 381                         // Test if it is an answer to a mail
 382                         if (DBA::exists('mail', ['uri' => $object_data['reply-to-id']])) {
 383                                 $object_data['directmessage'] = true;
 384                         } else {
 385                                 $object_data['directmessage'] = JsonLD::fetchElement($activity, 'litepub:directMessage');
 386                         }
 387                 } elseif (in_array($type, array_merge(self::ACTIVITY_TYPES, ['as:Follow'])) && in_array($object_type, self::CONTENT_TYPES)) {
 388                         // Create a mostly empty array out of the activity data (instead of the object).
 389                         // This way we later don't have to check for the existence of each individual array element.
 390                         $object_data = self::processObject($activity);
 391                         $object_data['name'] = $type;
 392                         $object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 393                         $object_data['object_id'] = $object_id;
 394                         $object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
 395                         $object_data['push'] = $push;
 396                 } elseif (in_array($type, ['as:Add', 'as:Remove'])) {
 397                         $object_data = [];
 398                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 399                         $object_data['target_id'] = JsonLD::fetchElement($activity, 'as:target', '@id');
 400                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 401                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 402                         $object_data['object_content'] = JsonLD::fetchElement($activity['as:object'], 'as:content', '@type');
 403                         $object_data['push'] = $push;
 404                 } else {
 405                         $object_data = [];
 406                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 407                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 408                         $object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor', '@id');
 409                         $object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
 410                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 411                         $object_data['push'] = $push;
 412
 413                         // An Undo is done on the object of an object, so we need that type as well
 414                         if (($type == 'as:Undo') && !empty($object_data['object_object'])) {
 415                                 $object_data['object_object_type'] = self::fetchObjectType([], $object_data['object_object'], $fetch_uid);
 416                         }
 417                 }
 418
 419                 $object_data = self::addActivityFields($object_data, $activity);
 420
 421                 if (empty($object_data['object_type'])) {
 422                         $object_data['object_type'] = $object_type;
 423                 }
 424
 425                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
 426                         if ((empty($object_data['receiver_urls'][$element]) || in_array($element, ['as:bto', 'as:bcc'])) && !empty($urls[$element])) {
 427                                 $object_data['receiver_urls'][$element] = array_unique(array_merge($object_data['receiver_urls'][$element] ?? [], $urls[$element]));
 428                         }
 429                 }
 430
 431                 $object_data['type'] = $type;
 432                 $object_data['actor'] = $actor;
 433                 $object_data['item_receiver'] = $receivers;
 434                 $object_data['receiver'] = array_replace($object_data['receiver'] ?? [], $receivers);
 435                 $object_data['reception_type'] = array_replace($object_data['reception_type'] ?? [], $reception_types);
 436
 437                 $author = $object_data['author'] ?? $actor;
 438                 if (!empty($author) && !empty($object_data['id'])) {
 439                         $author_host = parse_url($author, PHP_URL_HOST);
 440                         $id_host = parse_url($object_data['id'], PHP_URL_HOST);
 441                         if ($author_host == $id_host) {
 442                                 Logger::info('Valid hosts', ['type' => $type, 'host' => $id_host]);
 443                         } else {
 444                                 Logger::notice('Differing hosts on author and id', ['type' => $type, 'author' => $author_host, 'id' => $id_host]);
 445                                 $trust_source = false;
 446                         }
 447                 }
 448
 449                 Logger::info('Processing ' . $object_data['type'] . ' ' . $object_data['object_type'] . ' ' . $object_data['id']);
 450
 451                 return $object_data;
 452         }
 453
 454         /**
 455          * Fetches the first user id from the receiver array
 456          *
 457          * @param array $receivers Array with receivers
 458          * @return integer user id;
 459          */
 460         public static function getFirstUserFromReceivers($receivers)
 461         {
 462                 foreach ($receivers as $receiver) {
 463                         if (!empty($receiver)) {
 464                                 return $receiver;
 465                         }
 466                 }
 467                 return 0;
 468         }
 469
 470         /**
 471          * Processes the activity object
 472          *
 473          * @param array   $activity     Array with activity data
 474          * @param string  $body         The unprocessed body
 475          * @param integer $uid          User ID
 476          * @param boolean $trust_source Do we trust the source?
 477          * @param boolean $push         Message had been pushed to our system
 478          * @param array   $signer       The signer of the post
 479          * @throws \Exception
 480          */
 481         public static function processActivity($activity, string $body = '', int $uid = null, bool $trust_source = false, bool $push = false, array $signer = [])
 482         {
 483                 $type = JsonLD::fetchElement($activity, '@type');
 484                 if (!$type) {
 485                         Logger::info('Empty type', ['activity' => $activity]);
 486                         return;
 487                 }
 488
 489                 if (!JsonLD::fetchElement($activity, 'as:object', '@id')) {
 490                         Logger::info('Empty object', ['activity' => $activity]);
 491                         return;
 492                 }
 493
 494                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 495                 if (empty($actor)) {
 496                         Logger::info('Empty actor', ['activity' => $activity]);
 497                         return;
 498                 }
 499
 500                 if (is_array($activity['as:object'])) {
 501                         $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
 502                 } else {
 503                         $attributed_to = '';
 504                 }
 505
 506                 // Test the provided signatures against the actor and "attributedTo"
 507                 if ($trust_source) {
 508                         if (!empty($attributed_to) && !empty($actor)) {
 509                                 $trust_source = (in_array($actor, $signer) && in_array($attributed_to, $signer));
 510                         } else {
 511                                 $trust_source = in_array($actor, $signer);
 512                         }
 513                 }
 514
 515                 // $trust_source is called by reference and is set to true if the content was retrieved successfully
 516                 $object_data = self::prepareObjectData($activity, $uid, $push, $trust_source);
 517                 if (empty($object_data)) {
 518                         Logger::info('No object data found', ['activity' => $activity]);
 519                         return;
 520                 }
 521
 522                 // Lemmy is announcing activities.
 523                 // We are changing the announces into regular activities.
 524                 if (($type == 'as:Announce') && in_array($object_data['type'] ?? '', array_merge(self::ACTIVITY_TYPES, ['as:Delete', 'as:Undo', 'as:Update']))) {
 525                         $type = $object_data['type'];
 526                 }
 527
 528                 if (!$trust_source) {
 529                         Logger::info('Activity trust could not be achieved.',  ['id' => $object_data['object_id'], 'type' => $type, 'signer' => $signer, 'actor' => $actor, 'attributedTo' => $attributed_to]);
 530                         return;
 531                 }
 532
 533                 if (!empty($body) && empty($object_data['raw'])) {
 534                         $object_data['raw'] = $body;
 535                 }
 536
 537                 // Internal flag for thread completion. See Processor.php
 538                 if (!empty($activity['thread-completion'])) {
 539                         $object_data['thread-completion'] = $activity['thread-completion'];
 540                 }
 541
 542                 if (!empty($activity['completion-mode'])) {
 543                         $object_data['completion-mode'] = $activity['completion-mode'];
 544                 }
 545
 546                 if (!empty($activity['thread-children-type'])) {
 547                         $object_data['thread-children-type'] = $activity['thread-children-type'];
 548                 }
 549
 550                 // Internal flag for posts that arrived via relay
 551                 if (!empty($activity['from-relay'])) {
 552                         $object_data['from-relay'] = $activity['from-relay'];
 553                 }
 554
 555                 switch ($type) {
 556                         case 'as:Create':
 557                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 558                                         $item = ActivityPub\Processor::createItem($object_data);
 559                                         ActivityPub\Processor::postItem($object_data, $item);
 560                                 } elseif (in_array($object_data['object_type'], ['pt:CacheFile'])) {
 561                                         // Unhandled Peertube activity
 562                                 } else {
 563                                         self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 564                                 }
 565                                 break;
 566
 567                         case 'as:Invite':
 568                                 if (in_array($object_data['object_type'], ['as:Event'])) {
 569                                         $item = ActivityPub\Processor::createItem($object_data);
 570                                         ActivityPub\Processor::postItem($object_data, $item);
 571                                 } else {
 572                                         self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 573                                 }
 574                                 break;
 575
 576                         case 'as:Add':
 577                                 if ($object_data['object_type'] == 'as:tag') {
 578                                         ActivityPub\Processor::addTag($object_data);
 579                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 580                                         // Seems to be used by Mastodon to announce that a post is pinned
 581                                         self::storeUnhandledActivity(false, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 582                                 } elseif ($object_data['object_type'] == '') {
 583                                         // The object type couldn't be determined. We don't have it and we can't fetch it. We ignore this activity.
 584                                 } else {
 585                                         self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 586                                 }
 587                                 break;
 588
 589                         case 'as:Announce':
 590                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 591                                         $object_data['thread-completion'] = Contact::getIdForURL($actor);
 592                                         $object_data['completion-mode']   = self::COMPLETION_ANNOUCE;
 593
 594                                         $item = ActivityPub\Processor::createItem($object_data);
 595                                         if (empty($item)) {
 596                                                 return;
 597                                         }
 598
 599                                         $item['post-reason'] = Item::PR_ANNOUNCEMENT;
 600                                         ActivityPub\Processor::postItem($object_data, $item);
 601
 602                                         $announce_object_data = self::processObject($activity);
 603                                         $announce_object_data['name'] = $type;
 604                                         $announce_object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 605                                         $announce_object_data['object_id'] = $object_data['object_id'];
 606                                         $announce_object_data['object_type'] = $object_data['object_type'];
 607                                         $announce_object_data['push'] = $push;
 608
 609                                         if (!empty($body)) {
 610                                                 $announce_object_data['raw'] = $body;
 611                                         }
 612
 613                                         ActivityPub\Processor::createActivity($announce_object_data, Activity::ANNOUNCE);
 614                                 } else {
 615                                         self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 616                                 }
 617                                 break;
 618
 619                         case 'as:Like':
 620                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 621                                         ActivityPub\Processor::createActivity($object_data, Activity::LIKE);
 622                                 } elseif ($object_data['object_type'] == '') {
 623                                         // The object type couldn't be determined. We don't have it and we can't fetch it. We ignore this activity.
 624                                 } else {
 625                                         self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 626                                 }
 627                                 break;
 628
 629                         case 'as:Dislike':
 630                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 631                                         ActivityPub\Processor::createActivity($object_data, Activity::DISLIKE);
 632                                 } elseif ($object_data['object_type'] == '') {
 633                                         // The object type couldn't be determined. We don't have it and we can't fetch it. We ignore this activity.
 634                                 } else {
 635                                         self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 636                                 }
 637                                 break;
 638
 639                         case 'as:TentativeAccept':
 640                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 641                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDMAYBE);
 642                                 } else {
 643                                         self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 644                                 }
 645                                 break;
 646
 647                         case 'as:Update':
 648                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 649                                         ActivityPub\Processor::updateItem($object_data);
 650                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 651                                         ActivityPub\Processor::updatePerson($object_data);
 652                                 } elseif (in_array($object_data['object_type'], ['pt:CacheFile'])) {
 653                                         // Unhandled Peertube activity
 654                                 } else {
 655                                         self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 656                                 }
 657                                 break;
 658
 659                         case 'as:Delete':
 660                                 if (in_array($object_data['object_type'], array_merge(['as:Tombstone'], self::CONTENT_TYPES))) {
 661                                         ActivityPub\Processor::deleteItem($object_data);
 662                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 663                                         ActivityPub\Processor::deletePerson($object_data);
 664                                 } elseif ($object_data['object_type'] == '') {
 665                                         // The object type couldn't be determined. Most likely we don't have it here. We ignore this activity.
 666                                 } else {
 667                                         self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 668                                 }
 669                                 break;
 670
 671                         case 'as:Block':
 672                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 673                                         // Used by Mastodon to announce that the sender has blocked the account
 674                                         self::storeUnhandledActivity(false, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 675                                 } else {
 676                                         self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 677                                 }
 678                                 break;
 679
 680                         case 'as:Remove':
 681                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 682                                         // Seems to be used by Mastodon to remove the pinned status of a post
 683                                         self::storeUnhandledActivity(false, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 684                                 } elseif ($object_data['object_type'] == '') {
 685                                         // The object type couldn't be determined. We don't have it and we can't fetch it. We ignore this activity.
 686                                 } else {
 687                                         self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 688                                 }
 689                                 break;
 690
 691                         case 'as:Follow':
 692                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 693                                         ActivityPub\Processor::followUser($object_data);
 694                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 695                                         $object_data['reply-to-id'] = $object_data['object_id'];
 696                                         ActivityPub\Processor::createActivity($object_data, Activity::FOLLOW);
 697                                 } else {
 698                                         self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 699                                 }
 700                                 break;
 701
 702                         case 'as:Accept':
 703                                 if ($object_data['object_type'] == 'as:Follow') {
 704                                         ActivityPub\Processor::acceptFollowUser($object_data);
 705                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 706                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTEND);
 707                                 } else {
 708                                         self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 709                                 }
 710                                 break;
 711
 712                         case 'as:Reject':
 713                                 if ($object_data['object_type'] == 'as:Follow') {
 714                                         ActivityPub\Processor::rejectFollowUser($object_data);
 715                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 716                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDNO);
 717                                 } else {
 718                                         self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 719                                 }
 720                                 break;
 721
 722                         case 'as:Undo':
 723                                 if (($object_data['object_type'] == 'as:Follow') &&
 724                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 725                                         ActivityPub\Processor::undoFollowUser($object_data);
 726                                 } elseif (($object_data['object_type'] == 'as:Follow') &&
 727                                         in_array($object_data['object_object_type'], self::CONTENT_TYPES)) {
 728                                         ActivityPub\Processor::undoActivity($object_data);
 729                                 } elseif (($object_data['object_type'] == 'as:Accept') &&
 730                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 731                                         ActivityPub\Processor::rejectFollowUser($object_data);
 732                                 } elseif (in_array($object_data['object_type'], array_merge(self::ACTIVITY_TYPES, ['as:Announce'])) &&
 733                                         in_array($object_data['object_object_type'], array_merge(['as:Tombstone'], self::CONTENT_TYPES))) {
 734                                         ActivityPub\Processor::undoActivity($object_data);
 735                                 } elseif (in_array($object_data['object_type'], array_merge(self::ACTIVITY_TYPES, ['as:Announce', 'as:Create', ''])) &&
 736                                         ($object_data['object_object_type'] == '')) {
 737                                         // We cannot detect the target object. So we can ignore it.
 738                                 } elseif (in_array($object_data['object_type'], ['as:Create']) &&
 739                                         in_array($object_data['object_object_type'], ['pt:CacheFile'])) {
 740                                         // Unhandled Peertube activity
 741                                 } else {
 742                                         self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 743                                 }
 744                                 break;
 745
 746                         case 'as:View':
 747                                 if (in_array($object_data['object_type'], ['as:Note', 'as:Video'])) {
 748                                         // Unhandled Peertube activity
 749                                 } else {
 750                                         self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 751                                 }
 752                                 break;
 753
 754                         case 'litepub:EmojiReact':
 755                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 756                                         // Unhandled Pleroma activity to react to a post via an emoji
 757                                 } else {
 758                                         self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 759                                 }
 760                                 break;
 761
 762                         default:
 763                                 Logger::info('Unknown activity: ' . $type . ' ' . $object_data['object_type']);
 764                                 self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 765                                 break;
 766                 }
 767         }
 768
 769         /**
 770          * Stores unhandled or unknown Activitities as a file
 771          *
 772          * @param boolean $unknown      "true" if the activity is unknown, "false" if it is unhandled
 773          * @param string  $type         Activity type
 774          * @param array   $object_data  Preprocessed array that is generated out of the received activity
 775          * @param array   $activity     Array with activity data
 776          * @param string  $body         The unprocessed body
 777          * @param integer $uid          User ID
 778          * @param boolean $trust_source Do we trust the source?
 779          * @param boolean $push         Message had been pushed to our system
 780          * @param array   $signer       The signer of the post
 781          * @return void
 782          */
 783         private static function storeUnhandledActivity(bool $unknown, string $type, array $object_data, array $activity, string $body = '', int $uid = null, bool $trust_source = false, bool $push = false, array $signer = [])
 784         {
 785                 if (!DI::config()->get('debug', 'ap_log_unknown')) {
 786                         return;
 787                 }
 788
 789                 $tempfile = tempnam(System::getTempPath(), ($unknown  ? 'unknown-' : 'unhandled-') . str_replace(':', '-', $type) . '-' . str_replace(':', '-', $object_data['object_type']) . '-' . str_replace(':', '-', $object_data['object_object_type'] ?? '') . '-');
 790                 file_put_contents($tempfile, json_encode(['activity' => $activity, 'body' => $body, 'uid' => $uid, 'trust_source' => $trust_source, 'push' => $push, 'signer' => $signer, 'object_data' => $object_data], JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE));
 791                 Logger::notice('Unknown activity stored', ['type' => $type, 'object_type' => $object_data['object_type'], $object_data['object_object_type'] ?? '', 'file' => $tempfile]);
 792         }
 793
 794         /**
 795          * Fetch a user id from an activity array
 796          *
 797          * @param array  $activity
 798          * @param string $actor
 799          *
 800          * @return int   user id
 801          */
 802         public static function getBestUserForActivity(array $activity)
 803         {
 804                 $uid = 0;
 805                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id') ?? '';
 806
 807                 $receivers = self::getReceivers($activity, $actor);
 808                 foreach ($receivers as $receiver) {
 809                         if ($receiver['type'] == self::TARGET_GLOBAL) {
 810                                 return 0;
 811                         }
 812                         if (empty($uid) || ($receiver['type'] == self::TARGET_TO)) {
 813                                 $uid = $receiver['uid'];
 814                         }
 815                 }
 816
 817                 // When we haven't found any user yet, we just chose a user who most likely could have access to the content
 818                 if (empty($uid)) {
 819                         $contact = Contact::selectFirst(['uid'], ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND]]);
 820                         if (!empty($contact['uid'])) {
 821                                 $uid = $contact['uid'];
 822                         }
 823                 }
 824
 825                 return $uid;
 826         }
 827
 828         public static function getReceiverURL($activity)
 829         {
 830                 $urls = [];
 831
 832                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
 833                         $receiver_list = JsonLD::fetchElementArray($activity, $element, '@id');
 834                         if (empty($receiver_list)) {
 835                                 continue;
 836                         }
 837
 838                         foreach ($receiver_list as $receiver) {
 839                                 if ($receiver == self::PUBLIC_COLLECTION) {
 840                                         $receiver = ActivityPub::PUBLIC_COLLECTION;
 841                                 }
 842                                 $urls[$element][] = $receiver;
 843                         }
 844                 }
 845
 846                 return $urls;
 847         }
 848
 849         /**
 850          * Fetch the receiver list from an activity array
 851          *
 852          * @param array   $activity
 853          * @param string  $actor
 854          * @param array   $tags
 855          * @param boolean $fetch_unlisted
 856          *
 857          * @return array with receivers (user id)
 858          * @throws \Exception
 859          */
 860         private static function getReceivers($activity, $actor, $tags = [], $fetch_unlisted = false)
 861         {
 862                 $reply = $receivers = [];
 863
 864                 // When it is an answer, we inherite the receivers from the parent
 865                 $replyto = JsonLD::fetchElement($activity, 'as:inReplyTo', '@id');
 866                 if (!empty($replyto)) {
 867                         $reply = [$replyto];
 868
 869                         // Fix possibly wrong item URI (could be an answer to a plink uri)
 870                         $fixedReplyTo = Item::getURIByLink($replyto);
 871                         if (!empty($fixedReplyTo)) {
 872                                 $reply[] = $fixedReplyTo;
 873                         }
 874                 }
 875
 876                 // Fetch all posts that refer to the object id
 877                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 878                 if (!empty($object_id)) {
 879                         $reply[] = $object_id;
 880                 }
 881
 882                 if (!empty($reply)) {
 883                         $parents = Post::select(['uid'], ['uri' => $reply]);
 884                         while ($parent = Post::fetch($parents)) {
 885                                 $receivers[$parent['uid']] = ['uid' => $parent['uid'], 'type' => self::TARGET_ANSWER];
 886                         }
 887                         DBA::close($parents);
 888                 }
 889
 890                 if (!empty($actor)) {
 891                         $profile   = APContact::getByURL($actor);
 892                         $followers = $profile['followers'] ?? '';
 893                         $is_forum  = ($actor['type'] ?? '') == 'Group';
 894                         Logger::info('Got actor and followers', ['actor' => $actor, 'followers' => $followers]);
 895                 } else {
 896                         Logger::info('Empty actor', ['activity' => $activity]);
 897                         $followers = '';
 898                         $is_forum  = false;
 899                 }
 900
 901                 // We have to prevent false follower assumptions upon thread completions
 902                 $follower_target = empty($activity['thread-completion']) ? self::TARGET_FOLLOWER : self::TARGET_UNKNOWN;
 903
 904                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
 905                         $receiver_list = JsonLD::fetchElementArray($activity, $element, '@id');
 906                         if (empty($receiver_list)) {
 907                                 continue;
 908                         }
 909
 910                         foreach ($receiver_list as $receiver) {
 911                                 if ($receiver == self::PUBLIC_COLLECTION) {
 912                                         $receivers[0] = ['uid' => 0, 'type' => self::TARGET_GLOBAL];
 913                                 }
 914
 915                                 // Add receiver "-1" for unlisted posts
 916                                 if ($fetch_unlisted && ($receiver == self::PUBLIC_COLLECTION) && ($element == 'as:cc')) {
 917                                         $receivers[-1] = ['uid' => -1, 'type' => self::TARGET_GLOBAL];
 918                                 }
 919
 920                                 // Fetch the receivers for the public and the followers collection
 921                                 if ((($receiver == $followers) || (($receiver == self::PUBLIC_COLLECTION) && !$is_forum)) && !empty($actor)) {
 922                                         $receivers = self::getReceiverForActor($actor, $tags, $receivers, $follower_target);
 923                                         continue;
 924                                 }
 925
 926                                 // Fetching all directly addressed receivers
 927                                 $condition = ['self' => true, 'nurl' => Strings::normaliseLink($receiver)];
 928                                 $contact = DBA::selectFirst('contact', ['uid', 'contact-type'], $condition);
 929                                 if (!DBA::isResult($contact)) {
 930                                         continue;
 931                                 }
 932
 933                                 // Check if the potential receiver is following the actor
 934                                 // Exception: The receiver is targetted via "to" or this is a comment
 935                                 if ((($element != 'as:to') && empty($replyto)) || ($contact['contact-type'] == Contact::TYPE_COMMUNITY)) {
 936                                         $networks = Protocol::FEDERATED;
 937                                         $condition = ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
 938                                                 'network' => $networks, 'archive' => false, 'pending' => false, 'uid' => $contact['uid']];
 939
 940                                         // Forum posts are only accepted from forum contacts
 941                                         if ($contact['contact-type'] == Contact::TYPE_COMMUNITY) {
 942                                                 $condition['rel'] = [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER];
 943                                         }
 944
 945                                         if (!DBA::exists('contact', $condition)) {
 946                                                 continue;
 947                                         }
 948                                 }
 949
 950                                 $type = $receivers[$contact['uid']]['type'] ?? self::TARGET_UNKNOWN;
 951                                 if (in_array($type, [self::TARGET_UNKNOWN, self::TARGET_FOLLOWER, self::TARGET_ANSWER, self::TARGET_GLOBAL])) {
 952                                         switch ($element) {
 953                                                 case 'as:to':
 954                                                         $type = self::TARGET_TO;
 955                                                         break;
 956                                                 case 'as:cc':
 957                                                         $type = self::TARGET_CC;
 958                                                         break;
 959                                                 case 'as:bto':
 960                                                         $type = self::TARGET_BTO;
 961                                                         break;
 962                                                 case 'as:bcc':
 963                                                         $type = self::TARGET_BCC;
 964                                                         break;
 965                                         }
 966
 967                                         $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $type];
 968                                 }
 969                         }
 970                 }
 971
 972                 self::switchContacts($receivers, $actor);
 973
 974                 return $receivers;
 975         }
 976
 977         /**
 978          * Fetch the receiver list of a given actor
 979          *
 980          * @param string  $actor
 981          * @param array   $tags
 982          * @param array   $receivers
 983          * @param integer $target_type
 984          *
 985          * @return array with receivers (user id)
 986          * @throws \Exception
 987          */
 988         private static function getReceiverForActor($actor, $tags, $receivers, $target_type)
 989         {
 990                 $basecondition = ['rel' => [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER],
 991                         'network' => Protocol::FEDERATED, 'archive' => false, 'pending' => false];
 992
 993                 $condition = DBA::mergeConditions($basecondition, ["`nurl` = ? AND `uid` != ?", Strings::normaliseLink($actor), 0]);
 994                 $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
 995                 while ($contact = DBA::fetch($contacts)) {
 996                         if (empty($receivers[$contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
 997                                 $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $target_type];
 998                         }
 999                 }
1000                 DBA::close($contacts);
1001
1002                 // The queries are split because of performance issues
1003                 $condition = DBA::mergeConditions($basecondition, ["`alias` IN (?, ?) AND `uid` != ?", Strings::normaliseLink($actor), $actor, 0]);
1004                 $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
1005                 while ($contact = DBA::fetch($contacts)) {
1006                         if (empty($receivers[$contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
1007                                 $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $target_type];
1008                         }
1009                 }
1010                 DBA::close($contacts);
1011                 return $receivers;
1012         }
1013
1014         /**
1015          * Tests if the contact is a valid receiver for this actor
1016          *
1017          * @param array  $contact
1018          * @param string $actor
1019          * @param array  $tags
1020          *
1021          * @return bool with receivers (user id)
1022          * @throws \Exception
1023          */
1024         private static function isValidReceiverForActor($contact, $tags)
1025         {
1026                 // Are we following the contact? Then this is a valid receiver
1027                 if (in_array($contact['rel'], [Contact::SHARING, Contact::FRIEND])) {
1028                         return true;
1029                 }
1030
1031                 // When the possible receiver isn't a community, then it is no valid receiver
1032                 $owner = User::getOwnerDataById($contact['uid']);
1033                 if (empty($owner) || ($owner['contact-type'] != Contact::TYPE_COMMUNITY)) {
1034                         return false;
1035                 }
1036
1037                 // Is the community account tagged?
1038                 foreach ($tags as $tag) {
1039                         if ($tag['type'] != 'Mention') {
1040                                 continue;
1041                         }
1042
1043                         if (Strings::compareLink($tag['href'], $owner['url'])) {
1044                                 return true;
1045                         }
1046                 }
1047
1048                 return false;
1049         }
1050
1051         /**
1052          * Switches existing contacts to ActivityPub
1053          *
1054          * @param integer $cid Contact ID
1055          * @param integer $uid User ID
1056          * @param string  $url Profile URL
1057          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1058          * @throws \ImagickException
1059          */
1060         public static function switchContact($cid, $uid, $url)
1061         {
1062                 if (DBA::exists('contact', ['id' => $cid, 'network' => Protocol::ACTIVITYPUB])) {
1063                         Logger::info('Contact is already ActivityPub', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
1064                         return;
1065                 }
1066
1067                 if (Contact::updateFromProbe($cid)) {
1068                         Logger::info('Update was successful', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
1069                 }
1070
1071                 // Send a new follow request to be sure that the connection still exists
1072                 if (($uid != 0) && DBA::exists('contact', ['id' => $cid, 'rel' => [Contact::SHARING, Contact::FRIEND], 'network' => Protocol::ACTIVITYPUB])) {
1073                         Logger::info('Contact had been switched to ActivityPub. Sending a new follow request.', ['uid' => $uid, 'url' => $url]);
1074                         ActivityPub\Transmitter::sendActivity('Follow', $url, $uid);
1075                 }
1076         }
1077
1078         /**
1079          *
1080          *
1081          * @param $receivers
1082          * @param $actor
1083          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1084          * @throws \ImagickException
1085          */
1086         private static function switchContacts($receivers, $actor)
1087         {
1088                 if (empty($actor)) {
1089                         return;
1090                 }
1091
1092                 foreach ($receivers as $receiver) {
1093                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver['uid'], 'network' => Protocol::OSTATUS, 'nurl' => Strings::normaliseLink($actor)]);
1094                         if (DBA::isResult($contact)) {
1095                                 self::switchContact($contact['id'], $receiver['uid'], $actor);
1096                         }
1097
1098                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver['uid'], 'network' => Protocol::OSTATUS, 'alias' => [Strings::normaliseLink($actor), $actor]]);
1099                         if (DBA::isResult($contact)) {
1100                                 self::switchContact($contact['id'], $receiver['uid'], $actor);
1101                         }
1102                 }
1103         }
1104
1105         /**
1106          *
1107          *
1108          * @param       $object_data
1109          * @param array $activity
1110          *
1111          * @return mixed
1112          */
1113         private static function addActivityFields($object_data, $activity)
1114         {
1115                 if (!empty($activity['published']) && empty($object_data['published'])) {
1116                         $object_data['published'] = JsonLD::fetchElement($activity, 'as:published', '@value');
1117                 }
1118
1119                 if (!empty($activity['diaspora:guid']) && empty($object_data['diaspora:guid'])) {
1120                         $object_data['diaspora:guid'] = JsonLD::fetchElement($activity, 'diaspora:guid', '@value');
1121                 }
1122
1123                 $object_data['service'] = JsonLD::fetchElement($activity, 'as:instrument', 'as:name', '@type', 'as:Service');
1124                 $object_data['service'] = JsonLD::fetchElement($object_data, 'service', '@value');
1125
1126                 if (!empty($object_data['object_id'])) {
1127                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
1128                         $objectId = Item::getURIByLink($object_data['object_id']);
1129                         if (!empty($objectId) && ($object_data['object_id'] != $objectId)) {
1130                                 Logger::notice('Fix wrong object-id', ['received' => $object_data['object_id'], 'correct' => $objectId]);
1131                                 $object_data['object_id'] = $objectId;
1132                         }
1133                 }
1134
1135                 return $object_data;
1136         }
1137
1138         /**
1139          * Fetches the object data from external ressources if needed
1140          *
1141          * @param string  $object_id    Object ID of the the provided object
1142          * @param array   $object       The provided object array
1143          * @param boolean $trust_source Do we trust the provided object?
1144          * @param integer $uid          User ID for the signature that we use to fetch data
1145          *
1146          * @return array|false with trusted and valid object data
1147          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1148          * @throws \ImagickException
1149          */
1150         private static function fetchObject(string $object_id, array $object = [], bool $trust_source = false, int $uid = 0)
1151         {
1152                 // By fetching the type we check if the object is complete.
1153                 $type = JsonLD::fetchElement($object, '@type');
1154
1155                 if (!$trust_source || empty($type)) {
1156                         $data = ActivityPub::fetchContent($object_id, $uid);
1157                         if (!empty($data)) {
1158                                 $object = JsonLD::compact($data);
1159                                 Logger::info('Fetched content for ' . $object_id);
1160                         } else {
1161                                 Logger::info('Empty content for ' . $object_id . ', check if content is available locally.');
1162
1163                                 $item = Post::selectFirst(Item::DELIVER_FIELDLIST, ['uri' => $object_id]);
1164                                 if (!DBA::isResult($item)) {
1165                                         Logger::info('Object with url ' . $object_id . ' was not found locally.');
1166                                         return false;
1167                                 }
1168                                 Logger::info('Using already stored item for url ' . $object_id);
1169                                 $data = ActivityPub\Transmitter::createNote($item);
1170                                 $object = JsonLD::compact($data);
1171                         }
1172
1173                         $id = JsonLD::fetchElement($object, '@id');
1174                         if (empty($id)) {
1175                                 Logger::info('Empty id');
1176                                 return false;
1177                         }
1178
1179                         if ($id != $object_id) {
1180                                 Logger::info('Fetched id differs from provided id', ['provided' => $object_id, 'fetched' => $id]);
1181                                 return false;
1182                         }
1183                 } else {
1184                         Logger::info('Using original object for url ' . $object_id);
1185                 }
1186
1187                 $type = JsonLD::fetchElement($object, '@type');
1188                 if (empty($type)) {
1189                         Logger::info('Empty type');
1190                         return false;
1191                 }
1192
1193                 // Lemmy is resharing "create" activities instead of content
1194                 // We fetch the content from the activity.
1195                 if (in_array($type, ['as:Create'])) {
1196                         $object = $object['as:object'];
1197                         $type = JsonLD::fetchElement($object, '@type');
1198                         if (empty($type)) {
1199                                 Logger::info('Empty type');
1200                                 return false;
1201                         }
1202                         $object_data = self::processObject($object);
1203                 }
1204
1205                 // We currently don't handle 'pt:CacheFile', but with this step we avoid logging
1206                 if (in_array($type, self::CONTENT_TYPES) || ($type == 'pt:CacheFile')) {
1207                         $object_data = self::processObject($object);
1208
1209                         if (!empty($data)) {
1210                                 $object_data['raw'] = json_encode($data);
1211                         }
1212                         return $object_data;
1213                 }
1214
1215                 if ($type == 'as:Announce') {
1216                         $object_id = JsonLD::fetchElement($object, 'object', '@id');
1217                         if (empty($object_id) || !is_string($object_id)) {
1218                                 return false;
1219                         }
1220                         return self::fetchObject($object_id, [], false, $uid);
1221                 }
1222
1223                 Logger::info('Unhandled object type: ' . $type);
1224                 return false;
1225         }
1226
1227         /**
1228          * Converts the language element (Used by Peertube)
1229          *
1230          * @param array $languages
1231          * @return array Languages
1232          */
1233         public static function processLanguages(array $languages)
1234         {
1235                 if (empty($languages)) {
1236                         return [];
1237                 }
1238
1239                 $language_list = [];
1240
1241                 foreach ($languages as $language) {
1242                         if (!empty($language['_:identifier']) && !empty($language['as:name'])) {
1243                                 $language_list[$language['_:identifier']] = $language['as:name'];
1244                         }
1245                 }
1246                 return $language_list;
1247         }
1248
1249         /**
1250          * Convert tags from JSON-LD format into a simplified format
1251          *
1252          * @param array $tags Tags in JSON-LD format
1253          *
1254          * @return array with tags in a simplified format
1255          */
1256         public static function processTags(array $tags)
1257         {
1258                 $taglist = [];
1259
1260                 foreach ($tags as $tag) {
1261                         if (empty($tag)) {
1262                                 continue;
1263                         }
1264
1265                         $element = ['type' => str_replace('as:', '', JsonLD::fetchElement($tag, '@type')),
1266                                 'href' => JsonLD::fetchElement($tag, 'as:href', '@id'),
1267                                 'name' => JsonLD::fetchElement($tag, 'as:name', '@value')];
1268
1269                         if (empty($element['type'])) {
1270                                 continue;
1271                         }
1272
1273                         if (empty($element['href'])) {
1274                                 $element['href'] = $element['name'];
1275                         }
1276
1277                         $taglist[] = $element;
1278                 }
1279                 return $taglist;
1280         }
1281
1282         /**
1283          * Convert emojis from JSON-LD format into a simplified format
1284          *
1285          * @param array $emojis
1286          * @return array with emojis in a simplified format
1287          */
1288         private static function processEmojis(array $emojis)
1289         {
1290                 $emojilist = [];
1291
1292                 foreach ($emojis as $emoji) {
1293                         if (empty($emoji) || (JsonLD::fetchElement($emoji, '@type') != 'toot:Emoji') || empty($emoji['as:icon'])) {
1294                                 continue;
1295                         }
1296
1297                         $url = JsonLD::fetchElement($emoji['as:icon'], 'as:url', '@id');
1298                         $element = ['name' => JsonLD::fetchElement($emoji, 'as:name', '@value'),
1299                                 'href' => $url];
1300
1301                         $emojilist[] = $element;
1302                 }
1303
1304                 return $emojilist;
1305         }
1306
1307         /**
1308          * Convert attachments from JSON-LD format into a simplified format
1309          *
1310          * @param array $attachments Attachments in JSON-LD format
1311          *
1312          * @return array Attachments in a simplified format
1313          */
1314         private static function processAttachments(array $attachments)
1315         {
1316                 $attachlist = [];
1317
1318                 // Removes empty values
1319                 $attachments = array_filter($attachments);
1320
1321                 foreach ($attachments as $attachment) {
1322                         switch (JsonLD::fetchElement($attachment, '@type')) {
1323                                 case 'as:Page':
1324                                         $pageUrl = null;
1325                                         $pageImage = null;
1326
1327                                         $urls = JsonLD::fetchElementArray($attachment, 'as:url');
1328                                         foreach ($urls as $url) {
1329                                                 // Single scalar URL case
1330                                                 if (is_string($url)) {
1331                                                         $pageUrl = $url;
1332                                                         continue;
1333                                                 }
1334
1335                                                 $href = JsonLD::fetchElement($url, 'as:href', '@id');
1336                                                 $mediaType = JsonLD::fetchElement($url, 'as:mediaType', '@value');
1337                                                 if (Strings::startsWith($mediaType, 'image')) {
1338                                                         $pageImage = $href;
1339                                                 } else {
1340                                                         $pageUrl = $href;
1341                                                 }
1342                                         }
1343
1344                                         $attachlist[] = [
1345                                                 'type'  => 'link',
1346                                                 'title' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1347                                                 'desc'  => JsonLD::fetchElement($attachment, 'as:summary', '@value'),
1348                                                 'url'   => $pageUrl,
1349                                                 'image' => $pageImage,
1350                                         ];
1351                                         break;
1352                                 case 'as:Image':
1353                                         $mediaType = JsonLD::fetchElement($attachment, 'as:mediaType', '@value');
1354                                         $imageFullUrl = JsonLD::fetchElement($attachment, 'as:url', '@id');
1355                                         $imagePreviewUrl = null;
1356                                         // Multiple URLs?
1357                                         if (!$imageFullUrl && ($urls = JsonLD::fetchElementArray($attachment, 'as:url'))) {
1358                                                 $imageVariants = [];
1359                                                 $previewVariants = [];
1360                                                 foreach ($urls as $url) {
1361                                                         // Scalar URL, no discrimination possible
1362                                                         if (is_string($url)) {
1363                                                                 $imageFullUrl = $url;
1364                                                                 continue;
1365                                                         }
1366
1367                                                         // Not sure what to do with a different Link media type than the base Image, we skip
1368                                                         if ($mediaType != JsonLD::fetchElement($url, 'as:mediaType', '@value')) {
1369                                                                 continue;
1370                                                         }
1371
1372                                                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1373
1374                                                         // Default URL choice if no discriminating width is provided
1375                                                         $imageFullUrl = $href ?? $imageFullUrl;
1376
1377                                                         $width = intval(JsonLD::fetchElement($url, 'as:width', '@value') ?? 1);
1378
1379                                                         if ($href && $width) {
1380                                                                 $imageVariants[$width] = $href;
1381                                                                 // 632 is the ideal width for full screen frio posts, we compute the absolute distance to it
1382                                                                 $previewVariants[abs(632 - $width)] = $href;
1383                                                         }
1384                                                 }
1385
1386                                                 if ($imageVariants) {
1387                                                         // Taking the maximum size image
1388                                                         ksort($imageVariants);
1389                                                         $imageFullUrl = array_pop($imageVariants);
1390
1391                                                         // Taking the minimum number distance to the target distance
1392                                                         ksort($previewVariants);
1393                                                         $imagePreviewUrl = array_shift($previewVariants);
1394                                                 }
1395
1396                                                 unset($imageVariants);
1397                                                 unset($previewVariants);
1398                                         }
1399
1400                                         $attachlist[] = [
1401                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1402                                                 'mediaType' => $mediaType,
1403                                                 'name'  => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1404                                                 'url'   => $imageFullUrl,
1405                                                 'image' => $imagePreviewUrl !== $imageFullUrl ? $imagePreviewUrl : null,
1406                                         ];
1407                                         break;
1408                                 default:
1409                                         $attachlist[] = [
1410                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1411                                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType', '@value'),
1412                                                 'name' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1413                                                 'url' => JsonLD::fetchElement($attachment, 'as:url', '@id'),
1414                                                 'height' => JsonLD::fetchElement($attachment, 'as:height', '@value'),
1415                                                 'width' => JsonLD::fetchElement($attachment, 'as:width', '@value'),
1416                                                 'image' => JsonLD::fetchElement($attachment, 'as:image', '@id')
1417                                         ];
1418                         }
1419                 }
1420
1421                 return $attachlist;
1422         }
1423
1424         /**
1425          * Fetch the original source or content with the "language" Markdown or HTML
1426          *
1427          * @param array $object
1428          * @param array $object_data
1429          *
1430          * @return array
1431          * @throws \Exception
1432          */
1433         private static function getSource($object, $object_data)
1434         {
1435                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/bbcode');
1436                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1437                 if (!empty($object_data['source'])) {
1438                         return $object_data;
1439                 }
1440
1441                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/markdown');
1442                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1443                 if (!empty($object_data['source'])) {
1444                         $object_data['source'] = Markdown::toBBCode($object_data['source']);
1445                         return $object_data;
1446                 }
1447
1448                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/html');
1449                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1450                 if (!empty($object_data['source'])) {
1451                         $object_data['source'] = HTML::toBBCode($object_data['source']);
1452                         return $object_data;
1453                 }
1454
1455                 return $object_data;
1456         }
1457
1458         /**
1459          * Extracts a potential alternate URL from a list of additional URL elements
1460          *
1461          * @param array $urls
1462          * @return string
1463          */
1464         private static function extractAlternateUrl(array $urls): string
1465         {
1466                 $alternateUrl = '';
1467                 foreach ($urls as $key => $url) {
1468                         // Not a list but a single URL element
1469                         if (!is_numeric($key)) {
1470                                 continue;
1471                         }
1472
1473                         if (empty($url['@type']) || ($url['@type'] != 'as:Link')) {
1474                                 continue;
1475                         }
1476
1477                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1478                         if (empty($href)) {
1479                                 continue;
1480                         }
1481
1482                         $mediatype = JsonLD::fetchElement($url, 'as:mediaType');
1483                         if (empty($mediatype)) {
1484                                 continue;
1485                         }
1486
1487                         if ($mediatype == 'text/html') {
1488                                 $alternateUrl = $href;
1489                         }
1490                 }
1491
1492                 return $alternateUrl;
1493         }
1494
1495         /**
1496          * Check if the "as:url" element is an array with multiple links
1497          * This is the case with audio and video posts.
1498          * Then the links are added as attachments
1499          *
1500          * @param array $urls The object URL list
1501          * @return array an array of attachments
1502          */
1503         private static function processAttachmentUrls(array $urls): array
1504         {
1505                 $attachments = [];
1506                 foreach ($urls as $key => $url) {
1507                         // Not a list but a single URL element
1508                         if (!is_numeric($key)) {
1509                                 continue;
1510                         }
1511
1512                         if (empty($url['@type']) || ($url['@type'] != 'as:Link')) {
1513                                 continue;
1514                         }
1515
1516                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1517                         if (empty($href)) {
1518                                 continue;
1519                         }
1520
1521                         $mediatype = JsonLD::fetchElement($url, 'as:mediaType');
1522                         if (empty($mediatype)) {
1523                                 continue;
1524                         }
1525
1526                         $filetype = strtolower(substr($mediatype, 0, strpos($mediatype, '/')));
1527
1528                         if ($filetype == 'audio') {
1529                                 $attachments[] = ['type' => $filetype, 'mediaType' => $mediatype, 'url' => $href, 'height' => null, 'size' => null, 'name' => ''];
1530                         } elseif ($filetype == 'video') {
1531                                 $height = (int)JsonLD::fetchElement($url, 'as:height', '@value');
1532                                 // PeerTube audio-only track
1533                                 if ($height === 0) {
1534                                         continue;
1535                                 }
1536
1537                                 $size = (int)JsonLD::fetchElement($url, 'pt:size', '@value');
1538                                 $attachments[] = ['type' => $filetype, 'mediaType' => $mediatype, 'url' => $href, 'height' => $height, 'size' => $size, 'name' => ''];
1539                         } elseif (in_array($mediatype, ['application/x-bittorrent', 'application/x-bittorrent;x-scheme-handler/magnet'])) {
1540                                 $height = (int)JsonLD::fetchElement($url, 'as:height', '@value');
1541
1542                                 // For Torrent links we always store the highest resolution
1543                                 if (!empty($attachments[$mediatype]['height']) && ($height < $attachments[$mediatype]['height'])) {
1544                                         continue;
1545                                 }
1546
1547                                 $attachments[$mediatype] = ['type' => $mediatype, 'mediaType' => $mediatype, 'url' => $href, 'height' => $height, 'size' => null, 'name' => ''];
1548                         } elseif ($mediatype == 'application/x-mpegURL') {
1549                                 // PeerTube exception, actual video link is in the tags of this URL element
1550                                 $attachments = array_merge($attachments, self::processAttachmentUrls($url['as:tag']));
1551                         }
1552                 }
1553
1554                 return array_values($attachments);
1555         }
1556
1557         /**
1558          * Fetches data from the object part of an activity
1559          *
1560          * @param array $object
1561          *
1562          * @return array
1563          * @throws \Exception
1564          */
1565         private static function processObject($object)
1566         {
1567                 if (!JsonLD::fetchElement($object, '@id')) {
1568                         return false;
1569                 }
1570
1571                 $object_data = [];
1572                 $object_data['object_type'] = JsonLD::fetchElement($object, '@type');
1573                 $object_data['id'] = JsonLD::fetchElement($object, '@id');
1574                 $object_data['reply-to-id'] = JsonLD::fetchElement($object, 'as:inReplyTo', '@id');
1575
1576                 // An empty "id" field is translated to "./" by the compactor, so we have to check for this content
1577                 if (empty($object_data['reply-to-id']) || ($object_data['reply-to-id'] == './')) {
1578                         $object_data['reply-to-id'] = $object_data['id'];
1579
1580                         // On activities the "reply to" is the id of the object it refers to
1581                         if (in_array($object_data['object_type'], self::ACTIVITY_TYPES)) {
1582                                 $object_id = JsonLD::fetchElement($object, 'as:object', '@id');
1583                                 if (!empty($object_id)) {
1584                                         $object_data['reply-to-id'] = $object_id;
1585                                 }
1586                         }
1587                 } else {
1588                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
1589                         $replyToId = Item::getURIByLink($object_data['reply-to-id']);
1590                         if (!empty($replyToId) && ($object_data['reply-to-id'] != $replyToId)) {
1591                                 Logger::notice('Fix wrong reply-to', ['received' => $object_data['reply-to-id'], 'correct' => $replyToId]);
1592                                 $object_data['reply-to-id'] = $replyToId;
1593                         }
1594                 }
1595
1596                 $object_data['published'] = JsonLD::fetchElement($object, 'as:published', '@value');
1597                 $object_data['updated'] = JsonLD::fetchElement($object, 'as:updated', '@value');
1598
1599                 if (empty($object_data['updated'])) {
1600                         $object_data['updated'] = $object_data['published'];
1601                 }
1602
1603                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
1604                         $object_data['published'] = $object_data['updated'];
1605                 }
1606
1607                 $actor = JsonLD::fetchElement($object, 'as:attributedTo', '@id');
1608                 if (empty($actor)) {
1609                         $actor = JsonLD::fetchElement($object, 'as:actor', '@id');
1610                 }
1611
1612                 $location = JsonLD::fetchElement($object, 'as:location', 'as:name', '@type', 'as:Place');
1613                 $location = JsonLD::fetchElement($location, 'location', '@value');
1614                 if ($location) {
1615                         // Some AP software allow formatted text in post location, so we run all the text converters we have to boil
1616                         // down to HTML and then finally format to plaintext.
1617                         $location = Markdown::convert($location);
1618                         $location = BBCode::toPlaintext($location);
1619                 }
1620
1621                 $object_data['sc:identifier'] = JsonLD::fetchElement($object, 'sc:identifier', '@value');
1622                 $object_data['diaspora:guid'] = JsonLD::fetchElement($object, 'diaspora:guid', '@value');
1623                 $object_data['diaspora:comment'] = JsonLD::fetchElement($object, 'diaspora:comment', '@value');
1624                 $object_data['diaspora:like'] = JsonLD::fetchElement($object, 'diaspora:like', '@value');
1625                 $object_data['actor'] = $object_data['author'] = $actor;
1626                 $object_data['context'] = JsonLD::fetchElement($object, 'as:context', '@id');
1627                 $object_data['conversation'] = JsonLD::fetchElement($object, 'ostatus:conversation', '@id');
1628                 $object_data['sensitive'] = JsonLD::fetchElement($object, 'as:sensitive');
1629                 $object_data['name'] = JsonLD::fetchElement($object, 'as:name', '@value');
1630                 $object_data['summary'] = JsonLD::fetchElement($object, 'as:summary', '@value');
1631                 $object_data['content'] = JsonLD::fetchElement($object, 'as:content', '@value');
1632                 $object_data['mediatype'] = JsonLD::fetchElement($object, 'as:mediaType', '@value');
1633                 $object_data = self::getSource($object, $object_data);
1634                 $object_data['start-time'] = JsonLD::fetchElement($object, 'as:startTime', '@value');
1635                 $object_data['end-time'] = JsonLD::fetchElement($object, 'as:endTime', '@value');
1636                 $object_data['location'] = $location;
1637                 $object_data['latitude'] = JsonLD::fetchElement($object, 'as:location', 'as:latitude', '@type', 'as:Place');
1638                 $object_data['latitude'] = JsonLD::fetchElement($object_data, 'latitude', '@value');
1639                 $object_data['longitude'] = JsonLD::fetchElement($object, 'as:location', 'as:longitude', '@type', 'as:Place');
1640                 $object_data['longitude'] = JsonLD::fetchElement($object_data, 'longitude', '@value');
1641                 $object_data['attachments'] = self::processAttachments(JsonLD::fetchElementArray($object, 'as:attachment') ?? []);
1642                 $object_data['tags'] = self::processTags(JsonLD::fetchElementArray($object, 'as:tag') ?? []);
1643                 $object_data['emojis'] = self::processEmojis(JsonLD::fetchElementArray($object, 'as:tag', null, '@type', 'toot:Emoji') ?? []);
1644                 $object_data['languages'] = self::processLanguages(JsonLD::fetchElementArray($object, 'sc:inLanguage') ?? []);
1645                 $object_data['generator'] = JsonLD::fetchElement($object, 'as:generator', 'as:name', '@type', 'as:Application');
1646                 $object_data['generator'] = JsonLD::fetchElement($object_data, 'generator', '@value');
1647                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'as:url', '@id');
1648
1649                 // Special treatment for Hubzilla links
1650                 if (is_array($object_data['alternate-url'])) {
1651                         $object_data['alternate-url'] = JsonLD::fetchElement($object_data['alternate-url'], 'as:href', '@id');
1652
1653                         if (!is_string($object_data['alternate-url'])) {
1654                                 $object_data['alternate-url'] = JsonLD::fetchElement($object['as:url'], 'as:href', '@id');
1655                         }
1656                 }
1657
1658                 if (in_array($object_data['object_type'], ['as:Audio', 'as:Video'])) {
1659                         $object_data['alternate-url'] = self::extractAlternateUrl($object['as:url'] ?? []) ?: $object_data['alternate-url'];
1660                         $object_data['attachments'] = array_merge($object_data['attachments'], self::processAttachmentUrls($object['as:url'] ?? []));
1661                 }
1662
1663                 // For page types we expect that the alternate url posts to some page.
1664                 // So we add this to the attachments if it differs from the id.
1665                 // Currently only Lemmy is using the page type.
1666                 if (($object_data['object_type'] == 'as:Page') && !empty($object_data['alternate-url']) && !Strings::compareLink($object_data['alternate-url'], $object_data['id'])) {
1667                         $object_data['attachments'][] = ['url' => $object_data['alternate-url']];
1668                         $object_data['alternate-url'] = null;
1669                 }
1670
1671                 $receiverdata = self::getReceivers($object, $object_data['actor'], $object_data['tags'], true);
1672                 $receivers = $reception_types = [];
1673                 foreach ($receiverdata as $key => $data) {
1674                         $receivers[$key] = $data['uid'];
1675                         $reception_types[$data['uid']] = $data['type'] ?? 0;
1676                 }
1677
1678                 $object_data['receiver_urls']  = self::getReceiverURL($object);
1679                 $object_data['receiver']       = $receivers;
1680                 $object_data['reception_type'] = $reception_types;
1681
1682                 $object_data['unlisted'] = in_array(-1, $object_data['receiver']);
1683                 unset($object_data['receiver'][-1]);
1684                 unset($object_data['reception_type'][-1]);
1685
1686                 // Common object data:
1687
1688                 // Unhandled
1689                 // @context, type, actor, signature, mediaType, duration, replies, icon
1690
1691                 // Also missing: (Defined in the standard, but currently unused)
1692                 // audience, preview, endTime, startTime, image
1693
1694                 // Data in Notes:
1695
1696                 // Unhandled
1697                 // contentMap, announcement_count, announcements, context_id, likes, like_count
1698                 // inReplyToStatusId, shares, quoteUrl, statusnetConversationId
1699
1700                 // Data in video:
1701
1702                 // To-Do?
1703                 // category, licence, language, commentsEnabled
1704
1705                 // Unhandled
1706                 // views, waitTranscoding, state, support, subtitleLanguage
1707                 // likes, dislikes, shares, comments
1708
1709                 return $object_data;
1710         }
1711 }