src/Protocol/ActivityPub/Receiver.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2020, Friendica
   4  *
   5  * @license GNU AGPL version 3 or any later version
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU Affero General Public License as
   9  * published by the Free Software Foundation, either version 3 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU Affero General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Affero General Public License
  18  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  19  *
  20  */
  21
  22 namespace Friendica\Protocol\ActivityPub;
  23
  24 use Friendica\Content\Text\BBCode;
  25 use Friendica\Database\DBA;
  26 use Friendica\Content\Text\HTML;
  27 use Friendica\Content\Text\Markdown;
  28 use Friendica\Core\Logger;
  29 use Friendica\Core\Protocol;
  30 use Friendica\Model\Contact;
  31 use Friendica\Model\APContact;
  32 use Friendica\Model\Item;
  33 use Friendica\Model\User;
  34 use Friendica\Protocol\Activity;
  35 use Friendica\Protocol\ActivityPub;
  36 use Friendica\Util\HTTPSignature;
  37 use Friendica\Util\JsonLD;
  38 use Friendica\Util\LDSignature;
  39 use Friendica\Util\Strings;
  40
  41 /**
  42  * ActivityPub Receiver Protocol class
  43  *
  44  * To-Do:
  45  * @todo Undo Announce
  46  *
  47  * Check what this is meant to do:
  48  * - Add
  49  * - Block
  50  * - Flag
  51  * - Remove
  52  * - Undo Block
  53  */
  54 class Receiver
  55 {
  56         const PUBLIC_COLLECTION = 'as:Public';
  57         const ACCOUNT_TYPES = ['as:Person', 'as:Organization', 'as:Service', 'as:Group', 'as:Application'];
  58         const CONTENT_TYPES = ['as:Note', 'as:Article', 'as:Video', 'as:Image', 'as:Event', 'as:Audio'];
  59         const ACTIVITY_TYPES = ['as:Like', 'as:Dislike', 'as:Accept', 'as:Reject', 'as:TentativeAccept'];
  60
  61         const TARGET_UNKNOWN = 0;
  62         const TARGET_TO = 1;
  63         const TARGET_CC = 2;
  64         const TARGET_BTO = 3;
  65         const TARGET_BCC = 4;
  66         const TARGET_FOLLOWER = 5;
  67         const TARGET_ANSWER = 6;
  68         const TARGET_GLOBAL = 7;
  69
  70         /**
  71          * Checks if the web request is done for the AP protocol
  72          *
  73          * @return bool is it AP?
  74          */
  75         public static function isRequest()
  76         {
  77                 return stristr($_SERVER['HTTP_ACCEPT'] ?? '', 'application/activity+json') ||
  78                         stristr($_SERVER['HTTP_ACCEPT'] ?? '', 'application/ld+json');
  79         }
  80
  81         /**
  82          * Checks incoming message from the inbox
  83          *
  84          * @param         $body
  85          * @param         $header
  86          * @param integer $uid User ID
  87          * @throws \Exception
  88          */
  89         public static function processInbox($body, $header, $uid)
  90         {
  91                 $activity = json_decode($body, true);
  92                 if (empty($activity)) {
  93                         Logger::warning('Invalid body.');
  94                         return;
  95                 }
  96
  97                 $ldactivity = JsonLD::compact($activity);
  98
  99                 $actor = JsonLD::fetchElement($ldactivity, 'as:actor', '@id');
 100
 101                 $apcontact = APContact::getByURL($actor);
 102                 if (!empty($apcontact) && ($apcontact['type'] == 'Application') && ($apcontact['nick'] == 'relay')) {
 103                         self::processRelayPost($ldactivity);
 104                         return;
 105                 }
 106
 107                 $http_signer = HTTPSignature::getSigner($body, $header);
 108                 if (empty($http_signer)) {
 109                         Logger::warning('Invalid HTTP signature, message will be discarded.');
 110                         return;
 111                 } else {
 112                         Logger::info('Valid HTTP signature', ['signer' => $http_signer]);
 113                 }
 114
 115                 $signer = [$http_signer];
 116
 117                 Logger::info('Message for user ' . $uid . ' is from actor ' . $actor);
 118
 119                 if (LDSignature::isSigned($activity)) {
 120                         $ld_signer = LDSignature::getSigner($activity);
 121                         if (empty($ld_signer)) {
 122                                 Logger::log('Invalid JSON-LD signature from ' . $actor, Logger::DEBUG);
 123                         } elseif ($ld_signer != $http_signer) {
 124                                 $signer[] = $ld_signer;
 125                         }
 126                         if (!empty($ld_signer && ($actor == $http_signer))) {
 127                                 Logger::log('The HTTP and the JSON-LD signature belong to ' . $ld_signer, Logger::DEBUG);
 128                                 $trust_source = true;
 129                         } elseif (!empty($ld_signer)) {
 130                                 Logger::log('JSON-LD signature is signed by ' . $ld_signer, Logger::DEBUG);
 131                                 $trust_source = true;
 132                         } elseif ($actor == $http_signer) {
 133                                 Logger::log('Bad JSON-LD signature, but HTTP signer fits the actor.', Logger::DEBUG);
 134                                 $trust_source = true;
 135                         } else {
 136                                 Logger::log('Invalid JSON-LD signature and the HTTP signer is different.', Logger::DEBUG);
 137                                 $trust_source = false;
 138                         }
 139                 } elseif ($actor == $http_signer) {
 140                         Logger::log('Trusting post without JSON-LD signature, The actor fits the HTTP signer.', Logger::DEBUG);
 141                         $trust_source = true;
 142                 } else {
 143                         Logger::log('No JSON-LD signature, different actor.', Logger::DEBUG);
 144                         $trust_source = false;
 145                 }
 146
 147                 self::processActivity($ldactivity, $body, $uid, $trust_source, true, $signer);
 148         }
 149
 150         /**
 151          * Process incoming posts from relays
 152          *
 153          * @param array $activity
 154          * @return void
 155          */
 156         private static function processRelayPost(array $activity)
 157         {
 158                 $type = JsonLD::fetchElement($activity, '@type');
 159                 if (!$type) {
 160                         Logger::info('Empty type', ['activity' => $activity]);
 161                         return;
 162                 }
 163
 164                 if ($type != 'as:Announce') {
 165                         Logger::info('Not an announcement', ['activity' => $activity]);
 166                         return;
 167                 }
 168
 169                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 170                 if (empty($object_id)) {
 171                         Logger::info('No object id found', ['activity' => $activity]);
 172                         return;
 173                 }
 174
 175                 Logger::info('Got relayed message id', ['id' => $object_id]);
 176
 177                 $item_id = Item::searchByLink($object_id);
 178                 if ($item_id) {
 179                         Logger::info('Relayed message already exists', ['id' => $object_id, 'item' => $item_id]);
 180                         return;
 181                 }
 182
 183                 Processor::fetchMissingActivity($object_id);
 184
 185                 $item_id = Item::searchByLink($object_id);
 186                 if ($item_id) {
 187                         Logger::info('Relayed message had been fetched and stored', ['id' => $object_id, 'item' => $item_id]);
 188                 } else {
 189                         Logger::notice('Relayed message had not been stored', ['id' => $object_id]);
 190                 }
 191         }
 192
 193         /**
 194          * Fetches the object type for a given object id
 195          *
 196          * @param array   $activity
 197          * @param string  $object_id Object ID of the the provided object
 198          * @param integer $uid       User ID
 199          *
 200          * @return string with object type
 201          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 202          * @throws \ImagickException
 203          */
 204         private static function fetchObjectType($activity, $object_id, $uid = 0)
 205         {
 206                 if (!empty($activity['as:object'])) {
 207                         $object_type = JsonLD::fetchElement($activity['as:object'], '@type');
 208                         if (!empty($object_type)) {
 209                                 return $object_type;
 210                         }
 211                 }
 212
 213                 if (Item::exists(['uri' => $object_id, 'gravity' => [GRAVITY_PARENT, GRAVITY_COMMENT]])) {
 214                         // We just assume "note" since it doesn't make a difference for the further processing
 215                         return 'as:Note';
 216                 }
 217
 218                 $profile = APContact::getByURL($object_id);
 219                 if (!empty($profile['type'])) {
 220                         return 'as:' . $profile['type'];
 221                 }
 222
 223                 $data = ActivityPub::fetchContent($object_id, $uid);
 224                 if (!empty($data)) {
 225                         $object = JsonLD::compact($data);
 226                         $type = JsonLD::fetchElement($object, '@type');
 227                         if (!empty($type)) {
 228                                 return $type;
 229                         }
 230                 }
 231
 232                 return null;
 233         }
 234
 235         /**
 236          * Prepare the object array
 237          *
 238          * @param array   $activity     Array with activity data
 239          * @param integer $uid          User ID
 240          * @param boolean $push         Message had been pushed to our system
 241          * @param boolean $trust_source Do we trust the source?
 242          *
 243          * @return array with object data
 244          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 245          * @throws \ImagickException
 246          */
 247         public static function prepareObjectData($activity, $uid, $push, &$trust_source)
 248         {
 249                 $id = JsonLD::fetchElement($activity, '@id');
 250                 if (!empty($id) && !$trust_source) {
 251                         $fetched_activity = ActivityPub::fetchContent($id, $uid ?? 0);
 252                         if (!empty($fetched_activity)) {
 253                                 $object = JsonLD::compact($fetched_activity);
 254                                 $fetched_id = JsonLD::fetchElement($object, '@id');
 255                                 if ($fetched_id == $id) {
 256                                         Logger::info('Activity had been fetched successfully', ['id' => $id]);
 257                                         $trust_source = true;
 258                                         $activity = $object;
 259                                 } else {
 260                                         Logger::info('Activity id is not equal', ['id' => $id, 'fetched' => $fetched_id]);
 261                                 }
 262                         } else {
 263                                 Logger::info('Activity could not been fetched', ['id' => $id]);
 264                         }
 265                 }
 266
 267                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 268                 if (empty($actor)) {
 269                         Logger::info('Empty actor', ['activity' => $activity]);
 270                         return [];
 271                 }
 272
 273                 $type = JsonLD::fetchElement($activity, '@type');
 274
 275                 // Fetch all receivers from to, cc, bto and bcc
 276                 $receiverdata = self::getReceivers($activity, $actor);
 277                 $receivers = $reception_types = [];
 278                 foreach ($receiverdata as $key => $data) {
 279                         $receivers[$key] = $data['uid'];
 280                         $reception_types[$data['uid']] = $data['type'] ?? 0;
 281                 }
 282
 283                 // When it is a delivery to a personal inbox we add that user to the receivers
 284                 if (!empty($uid)) {
 285                         $additional = ['uid:' . $uid => $uid];
 286                         $receivers = array_merge($receivers, $additional);
 287                         if (empty($reception_types[$uid]) || in_array($reception_types[$uid], [self::TARGET_UNKNOWN, self::TARGET_FOLLOWER, self::TARGET_ANSWER, self::TARGET_GLOBAL])) {
 288                                 $reception_types[$uid] = self::TARGET_BCC;
 289                         }
 290                 } else {
 291                         // We possibly need some user to fetch private content,
 292                         // so we fetch the first out ot the list.
 293                         $uid = self::getFirstUserFromReceivers($receivers);
 294                 }
 295
 296                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 297                 if (empty($object_id)) {
 298                         Logger::log('No object found', Logger::DEBUG);
 299                         return [];
 300                 }
 301
 302                 if (!is_string($object_id)) {
 303                         Logger::info('Invalid object id', ['object' => $object_id]);
 304                         return [];
 305                 }
 306
 307                 $object_type = self::fetchObjectType($activity, $object_id, $uid);
 308
 309                 // Fetch the content only on activities where this matters
 310                 if (in_array($type, ['as:Create', 'as:Update', 'as:Announce'])) {
 311                         // Always fetch on "Announce"
 312                         $object_data = self::fetchObject($object_id, $activity['as:object'], $trust_source && ($type != 'as:Announce'), $uid);
 313                         if (empty($object_data)) {
 314                                 Logger::log("Object data couldn't be processed", Logger::DEBUG);
 315                                 return [];
 316                         }
 317
 318                         $object_data['object_id'] = $object_id;
 319
 320                         if ($type == 'as:Announce') {
 321                                 $object_data['push'] = false;
 322                         } else {
 323                                 $object_data['push'] = $push;
 324                         }
 325
 326                         // Test if it is an answer to a mail
 327                         if (DBA::exists('mail', ['uri' => $object_data['reply-to-id']])) {
 328                                 $object_data['directmessage'] = true;
 329                         } else {
 330                                 $object_data['directmessage'] = JsonLD::fetchElement($activity, 'litepub:directMessage');
 331                         }
 332                 } elseif (in_array($type, array_merge(self::ACTIVITY_TYPES, ['as:Follow'])) && in_array($object_type, self::CONTENT_TYPES)) {
 333                         // Create a mostly empty array out of the activity data (instead of the object).
 334                         // This way we later don't have to check for the existence of ech individual array element.
 335                         $object_data = self::processObject($activity);
 336                         $object_data['name'] = $type;
 337                         $object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 338                         $object_data['object_id'] = $object_id;
 339                         $object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
 340                 } elseif (in_array($type, ['as:Add'])) {
 341                         $object_data = [];
 342                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 343                         $object_data['target_id'] = JsonLD::fetchElement($activity, 'as:target', '@id');
 344                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 345                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 346                         $object_data['object_content'] = JsonLD::fetchElement($activity['as:object'], 'as:content', '@type');
 347                 } else {
 348                         $object_data = [];
 349                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 350                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 351                         $object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor', '@id');
 352                         $object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
 353                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 354
 355                         // An Undo is done on the object of an object, so we need that type as well
 356                         if (($type == 'as:Undo') && !empty($object_data['object_object'])) {
 357                                 $object_data['object_object_type'] = self::fetchObjectType([], $object_data['object_object'], $uid);
 358                         }
 359                 }
 360
 361                 $object_data = self::addActivityFields($object_data, $activity);
 362
 363                 if (empty($object_data['object_type'])) {
 364                         $object_data['object_type'] = $object_type;
 365                 }
 366
 367                 $object_data['type'] = $type;
 368                 $object_data['actor'] = $actor;
 369                 $object_data['item_receiver'] = $receivers;
 370                 $object_data['receiver'] = array_merge($object_data['receiver'] ?? [], $receivers);
 371                 $object_data['reception_type'] = array_merge($object_data['reception_type'] ?? [], $reception_types);
 372
 373                 $author = $object_data['author'] ?? $actor;
 374                 if (!empty($author) && !empty($object_data['id'])) {
 375                         $author_host = parse_url($author, PHP_URL_HOST);
 376                         $id_host = parse_url($object_data['id'], PHP_URL_HOST);
 377                         if ($author_host == $id_host) {
 378                                 Logger::info('Valid hosts', ['type' => $type, 'host' => $id_host]);
 379                         } else {
 380                                 Logger::notice('Differing hosts on author and id', ['type' => $type, 'author' => $author_host, 'id' => $id_host]);
 381                                 $trust_source = false;
 382                         }
 383                 }
 384
 385                 Logger::log('Processing ' . $object_data['type'] . ' ' . $object_data['object_type'] . ' ' . $object_data['id'], Logger::DEBUG);
 386
 387                 return $object_data;
 388         }
 389
 390         /**
 391          * Fetches the first user id from the receiver array
 392          *
 393          * @param array $receivers Array with receivers
 394          * @return integer user id;
 395          */
 396         public static function getFirstUserFromReceivers($receivers)
 397         {
 398                 foreach ($receivers as $receiver) {
 399                         if (!empty($receiver)) {
 400                                 return $receiver;
 401                         }
 402                 }
 403                 return 0;
 404         }
 405
 406         /**
 407          * Processes the activity object
 408          *
 409          * @param array   $activity     Array with activity data
 410          * @param string  $body
 411          * @param integer $uid          User ID
 412          * @param boolean $trust_source Do we trust the source?
 413          * @param boolean $push         Message had been pushed to our system
 414          * @throws \Exception
 415          */
 416         public static function processActivity($activity, string $body = '', int $uid = null, bool $trust_source = false, bool $push = false, array $signer = [])
 417         {
 418                 $type = JsonLD::fetchElement($activity, '@type');
 419                 if (!$type) {
 420                         Logger::info('Empty type', ['activity' => $activity]);
 421                         return;
 422                 }
 423
 424                 if (!JsonLD::fetchElement($activity, 'as:object', '@id')) {
 425                         Logger::info('Empty object', ['activity' => $activity]);
 426                         return;
 427                 }
 428
 429                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 430                 if (empty($actor)) {
 431                         Logger::info('Empty actor', ['activity' => $activity]);
 432                         return;
 433                 }
 434
 435                 if (is_array($activity['as:object'])) {
 436                         $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
 437                 } else {
 438                         $attributed_to = '';
 439                 }
 440
 441                 // Test the provided signatures against the actor and "attributedTo"
 442                 if ($trust_source) {
 443                         if (!empty($attributed_to) && !empty($actor)) {
 444                                 $trust_source = (in_array($actor, $signer) && in_array($attributed_to, $signer));
 445                         } else {
 446                                 $trust_source = in_array($actor, $signer);
 447                         }
 448                 }
 449
 450                 // $trust_source is called by reference and is set to true if the content was retrieved successfully
 451                 $object_data = self::prepareObjectData($activity, $uid, $push, $trust_source);
 452                 if (empty($object_data)) {
 453                         Logger::info('No object data found', ['activity' => $activity]);
 454                         return;
 455                 }
 456
 457                 if (!$trust_source) {
 458                         Logger::info('Activity trust could not be achieved.',  ['id' => $object_data['object_id'], 'type' => $type, 'signer' => $signer, 'actor' => $actor, 'attributedTo' => $attributed_to]);
 459                         return;
 460                 }
 461
 462                 if (!empty($body) && empty($object_data['raw'])) {
 463                         $object_data['raw'] = $body;
 464                 }
 465
 466                 // Internal flag for thread completion. See Processor.php
 467                 if (!empty($activity['thread-completion'])) {
 468                         $object_data['thread-completion'] = $activity['thread-completion'];
 469                 }
 470
 471                 switch ($type) {
 472                         case 'as:Create':
 473                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 474                                         $item = ActivityPub\Processor::createItem($object_data);
 475                                         ActivityPub\Processor::postItem($object_data, $item);
 476                                 }
 477                                 break;
 478
 479                         case 'as:Add':
 480                                 if ($object_data['object_type'] == 'as:tag') {
 481                                         ActivityPub\Processor::addTag($object_data);
 482                                 }
 483                                 break;
 484
 485                         case 'as:Announce':
 486                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 487                                         $object_data['thread-completion'] = true;
 488
 489                                         $item = ActivityPub\Processor::createItem($object_data);
 490                                         if (empty($item)) {
 491                                                 return;
 492                                         }
 493
 494                                         $item['post-type'] = Item::PT_ANNOUNCEMENT;
 495                                         ActivityPub\Processor::postItem($object_data, $item);
 496
 497                                         $announce_object_data = self::processObject($activity);
 498                                         $announce_object_data['name'] = $type;
 499                                         $announce_object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 500                                         $announce_object_data['object_id'] = $object_data['object_id'];
 501                                         $announce_object_data['object_type'] = $object_data['object_type'];
 502                                         $announce_object_data['push'] = $push;
 503
 504                                         if (!empty($body)) {
 505                                                 $announce_object_data['raw'] = $body;
 506                                         }
 507
 508                                         ActivityPub\Processor::createActivity($announce_object_data, Activity::ANNOUNCE);
 509                                 }
 510                                 break;
 511
 512                         case 'as:Like':
 513                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 514                                         ActivityPub\Processor::createActivity($object_data, Activity::LIKE);
 515                                 }
 516                                 break;
 517
 518                         case 'as:Dislike':
 519                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 520                                         ActivityPub\Processor::createActivity($object_data, Activity::DISLIKE);
 521                                 }
 522                                 break;
 523
 524                         case 'as:TentativeAccept':
 525                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 526                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDMAYBE);
 527                                 }
 528                                 break;
 529
 530                         case 'as:Update':
 531                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 532                                         ActivityPub\Processor::updateItem($object_data);
 533                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 534                                         ActivityPub\Processor::updatePerson($object_data);
 535                                 }
 536                                 break;
 537
 538                         case 'as:Delete':
 539                                 if ($object_data['object_type'] == 'as:Tombstone') {
 540                                         ActivityPub\Processor::deleteItem($object_data);
 541                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 542                                         ActivityPub\Processor::deletePerson($object_data);
 543                                 }
 544                                 break;
 545
 546                         case 'as:Follow':
 547                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 548                                         ActivityPub\Processor::followUser($object_data);
 549                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 550                                         $object_data['reply-to-id'] = $object_data['object_id'];
 551                                         ActivityPub\Processor::createActivity($object_data, Activity::FOLLOW);
 552                                 }
 553                                 break;
 554
 555                         case 'as:Accept':
 556                                 if ($object_data['object_type'] == 'as:Follow') {
 557                                         ActivityPub\Processor::acceptFollowUser($object_data);
 558                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 559                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTEND);
 560                                 }
 561                                 break;
 562
 563                         case 'as:Reject':
 564                                 if ($object_data['object_type'] == 'as:Follow') {
 565                                         ActivityPub\Processor::rejectFollowUser($object_data);
 566                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 567                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDNO);
 568                                 }
 569                                 break;
 570
 571                         case 'as:Undo':
 572                                 if (($object_data['object_type'] == 'as:Follow') &&
 573                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 574                                         ActivityPub\Processor::undoFollowUser($object_data);
 575                                 } elseif (($object_data['object_type'] == 'as:Accept') &&
 576                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 577                                         ActivityPub\Processor::rejectFollowUser($object_data);
 578                                 } elseif (in_array($object_data['object_type'], self::ACTIVITY_TYPES) &&
 579                                         in_array($object_data['object_object_type'], self::CONTENT_TYPES)) {
 580                                         ActivityPub\Processor::undoActivity($object_data);
 581                                 }
 582                                 break;
 583
 584                         default:
 585                                 Logger::log('Unknown activity: ' . $type . ' ' . $object_data['object_type'], Logger::DEBUG);
 586                                 break;
 587                 }
 588         }
 589
 590         /**
 591          * Fetch the receiver list from an activity array
 592          *
 593          * @param array   $activity
 594          * @param string  $actor
 595          * @param array   $tags
 596          * @param boolean $fetch_unlisted
 597          *
 598          * @return array with receivers (user id)
 599          * @throws \Exception
 600          */
 601         private static function getReceivers($activity, $actor, $tags = [], $fetch_unlisted = false)
 602         {
 603                 $reply = $receivers = [];
 604
 605                 // When it is an answer, we inherite the receivers from the parent
 606                 $replyto = JsonLD::fetchElement($activity, 'as:inReplyTo', '@id');
 607                 if (!empty($replyto)) {
 608                         $reply = [$replyto];
 609
 610                         // Fix possibly wrong item URI (could be an answer to a plink uri)
 611                         $fixedReplyTo = Item::getURIByLink($replyto);
 612                         if (!empty($fixedReplyTo)) {
 613                                 $reply[] = $fixedReplyTo;
 614                         }
 615                 }
 616
 617                 // Fetch all posts that refer to the object id
 618                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 619                 if (!empty($object_id)) {
 620                         $reply[] = $object_id;
 621                 }
 622
 623                 if (!empty($reply)) {
 624                         $parents = Item::select(['uid'], ['uri' => $reply]);
 625                         while ($parent = Item::fetch($parents)) {
 626                                 $receivers['uid:' . $parent['uid']] = ['uid' => $parent['uid'], 'type' => self::TARGET_ANSWER];
 627                         }
 628                 }
 629
 630                 if (!empty($actor)) {
 631                         $profile = APContact::getByURL($actor);
 632                         $followers = $profile['followers'] ?? '';
 633
 634                         Logger::log('Actor: ' . $actor . ' - Followers: ' . $followers, Logger::DEBUG);
 635                 } else {
 636                         Logger::info('Empty actor', ['activity' => $activity]);
 637                         $followers = '';
 638                 }
 639
 640                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
 641                         $receiver_list = JsonLD::fetchElementArray($activity, $element, '@id');
 642                         if (empty($receiver_list)) {
 643                                 continue;
 644                         }
 645
 646                         foreach ($receiver_list as $receiver) {
 647                                 if ($receiver == self::PUBLIC_COLLECTION) {
 648                                         $receivers['uid:0'] = ['uid' => 0, 'type' => self::TARGET_GLOBAL];
 649                                 }
 650
 651                                 // Add receiver "-1" for unlisted posts
 652                                 if ($fetch_unlisted && ($receiver == self::PUBLIC_COLLECTION) && ($element == 'as:cc')) {
 653                                         $receivers['uid:-1'] = ['uid' => -1, 'type' => self::TARGET_GLOBAL];
 654                                 }
 655
 656                                 // Fetch the receivers for the public and the followers collection
 657                                 if (in_array($receiver, [$followers, self::PUBLIC_COLLECTION]) && !empty($actor)) {
 658                                         $receivers = self::getReceiverForActor($actor, $tags, $receivers);
 659                                         continue;
 660                                 }
 661
 662                                 // Fetching all directly addressed receivers
 663                                 $condition = ['self' => true, 'nurl' => Strings::normaliseLink($receiver)];
 664                                 $contact = DBA::selectFirst('contact', ['uid', 'contact-type'], $condition);
 665                                 if (!DBA::isResult($contact)) {
 666                                         continue;
 667                                 }
 668
 669                                 // Check if the potential receiver is following the actor
 670                                 // Exception: The receiver is targetted via "to" or this is a comment
 671                                 if ((($element != 'as:to') && empty($replyto)) || ($contact['contact-type'] == Contact::TYPE_COMMUNITY)) {
 672                                         $networks = Protocol::FEDERATED;
 673                                         $condition = ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
 674                                                 'network' => $networks, 'archive' => false, 'pending' => false, 'uid' => $contact['uid']];
 675
 676                                         // Forum posts are only accepted from forum contacts
 677                                         if ($contact['contact-type'] == Contact::TYPE_COMMUNITY) {
 678                                                 $condition['rel'] = [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER];
 679                                         }
 680
 681                                         if (!DBA::exists('contact', $condition)) {
 682                                                 continue;
 683                                         }
 684                                 }
 685
 686                                 $type = $receivers['uid:' . $contact['uid']]['type'] ?? self::TARGET_UNKNOWN;
 687                                 if (in_array($type, [self::TARGET_UNKNOWN, self::TARGET_FOLLOWER, self::TARGET_ANSWER, self::TARGET_GLOBAL])) {
 688                                         switch ($element) {
 689                                                 case 'as:to':
 690                                                         $type = self::TARGET_TO;
 691                                                         break;
 692                                                 case 'as:cc':
 693                                                         $type = self::TARGET_CC;
 694                                                         break;
 695                                                 case 'as:bto':
 696                                                         $type = self::TARGET_BTO;
 697                                                         break;
 698                                                 case 'as:bcc':
 699                                                         $type = self::TARGET_BCC;
 700                                                         break;
 701                                         }
 702
 703                                         $receivers['uid:' . $contact['uid']] = ['uid' => $contact['uid'], 'type' => $type];
 704                                 }
 705                         }
 706                 }
 707
 708                 self::switchContacts($receivers, $actor);
 709
 710                 return $receivers;
 711         }
 712
 713         /**
 714          * Fetch the receiver list of a given actor
 715          *
 716          * @param string $actor
 717          * @param array  $tags
 718          *
 719          * @return array with receivers (user id)
 720          * @throws \Exception
 721          */
 722         private static function getReceiverForActor($actor, $tags, $receivers)
 723         {
 724                 $basecondition = ['rel' => [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER],
 725                         'network' => Protocol::FEDERATED, 'archive' => false, 'pending' => false];
 726
 727                 $condition = DBA::mergeConditions($basecondition, ['nurl' => Strings::normaliseLink($actor)]);
 728                 $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
 729                 while ($contact = DBA::fetch($contacts)) {
 730                         if (empty($receivers['uid:' . $contact['uid']]) && self::isValidReceiverForActor($contact, $actor, $tags)) {
 731                                 $receivers['uid:' . $contact['uid']] = ['uid' => $contact['uid'], 'type' => self::TARGET_FOLLOWER];
 732                         }
 733                 }
 734                 DBA::close($contacts);
 735
 736                 // The queries are split because of performance issues
 737                 $condition = DBA::mergeConditions($basecondition, ["`alias` IN (?, ?)", Strings::normaliseLink($actor), $actor]);
 738                 $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
 739                 while ($contact = DBA::fetch($contacts)) {
 740                         if (empty($receivers['uid:' . $contact['uid']]) && self::isValidReceiverForActor($contact, $actor, $tags)) {
 741                                 $receivers['uid:' . $contact['uid']] = ['uid' => $contact['uid'], 'type' => self::TARGET_FOLLOWER];
 742                         }
 743                 }
 744                 DBA::close($contacts);
 745                 return $receivers;
 746         }
 747
 748         /**
 749          * Tests if the contact is a valid receiver for this actor
 750          *
 751          * @param array  $contact
 752          * @param string $actor
 753          * @param array  $tags
 754          *
 755          * @return bool with receivers (user id)
 756          * @throws \Exception
 757          */
 758         private static function isValidReceiverForActor($contact, $actor, $tags)
 759         {
 760                 // Public contacts are no valid receiver
 761                 if ($contact['uid'] == 0) {
 762                         return false;
 763                 }
 764
 765                 // Are we following the contact? Then this is a valid receiver
 766                 if (in_array($contact['rel'], [Contact::SHARING, Contact::FRIEND])) {
 767                         return true;
 768                 }
 769
 770                 // When the possible receiver isn't a community, then it is no valid receiver
 771                 $owner = User::getOwnerDataById($contact['uid']);
 772                 if (empty($owner) || ($owner['contact-type'] != Contact::TYPE_COMMUNITY)) {
 773                         return false;
 774                 }
 775
 776                 // Is the community account tagged?
 777                 foreach ($tags as $tag) {
 778                         if ($tag['type'] != 'Mention') {
 779                                 continue;
 780                         }
 781
 782                         if ($tag['href'] == $owner['url']) {
 783                                 return true;
 784                         }
 785                 }
 786
 787                 return false;
 788         }
 789
 790         /**
 791          * Switches existing contacts to ActivityPub
 792          *
 793          * @param integer $cid Contact ID
 794          * @param integer $uid User ID
 795          * @param string  $url Profile URL
 796          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 797          * @throws \ImagickException
 798          */
 799         public static function switchContact($cid, $uid, $url)
 800         {
 801                 if (DBA::exists('contact', ['id' => $cid, 'network' => Protocol::ACTIVITYPUB])) {
 802                         Logger::info('Contact is already ActivityPub', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
 803                         return;
 804                 }
 805
 806                 if (Contact::updateFromProbe($cid)) {
 807                         Logger::info('Update was successful', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
 808                 }
 809
 810                 // Send a new follow request to be sure that the connection still exists
 811                 if (($uid != 0) && DBA::exists('contact', ['id' => $cid, 'rel' => [Contact::SHARING, Contact::FRIEND], 'network' => Protocol::ACTIVITYPUB])) {
 812                         Logger::info('Contact had been switched to ActivityPub. Sending a new follow request.', ['uid' => $uid, 'url' => $url]);
 813                         ActivityPub\Transmitter::sendActivity('Follow', $url, $uid);
 814                 }
 815         }
 816
 817         /**
 818          *
 819          *
 820          * @param $receivers
 821          * @param $actor
 822          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 823          * @throws \ImagickException
 824          */
 825         private static function switchContacts($receivers, $actor)
 826         {
 827                 if (empty($actor)) {
 828                         return;
 829                 }
 830
 831                 foreach ($receivers as $receiver) {
 832                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver['uid'], 'network' => Protocol::OSTATUS, 'nurl' => Strings::normaliseLink($actor)]);
 833                         if (DBA::isResult($contact)) {
 834                                 self::switchContact($contact['id'], $receiver['uid'], $actor);
 835                         }
 836
 837                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver['uid'], 'network' => Protocol::OSTATUS, 'alias' => [Strings::normaliseLink($actor), $actor]]);
 838                         if (DBA::isResult($contact)) {
 839                                 self::switchContact($contact['id'], $receiver['uid'], $actor);
 840                         }
 841                 }
 842         }
 843
 844         /**
 845          *
 846          *
 847          * @param       $object_data
 848          * @param array $activity
 849          *
 850          * @return mixed
 851          */
 852         private static function addActivityFields($object_data, $activity)
 853         {
 854                 if (!empty($activity['published']) && empty($object_data['published'])) {
 855                         $object_data['published'] = JsonLD::fetchElement($activity, 'as:published', '@value');
 856                 }
 857
 858                 if (!empty($activity['diaspora:guid']) && empty($object_data['diaspora:guid'])) {
 859                         $object_data['diaspora:guid'] = JsonLD::fetchElement($activity, 'diaspora:guid', '@value');
 860                 }
 861
 862                 $object_data['service'] = JsonLD::fetchElement($activity, 'as:instrument', 'as:name', '@type', 'as:Service');
 863                 $object_data['service'] = JsonLD::fetchElement($object_data, 'service', '@value');
 864
 865                 if (!empty($object_data['object_id'])) {
 866                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
 867                         $objectId = Item::getURIByLink($object_data['object_id']);
 868                         if (!empty($objectId) && ($object_data['object_id'] != $objectId)) {
 869                                 Logger::notice('Fix wrong object-id', ['received' => $object_data['object_id'], 'correct' => $objectId]);
 870                                 $object_data['object_id'] = $objectId;
 871                         }
 872                 }
 873
 874                 return $object_data;
 875         }
 876
 877         /**
 878          * Fetches the object data from external ressources if needed
 879          *
 880          * @param string  $object_id    Object ID of the the provided object
 881          * @param array   $object       The provided object array
 882          * @param boolean $trust_source Do we trust the provided object?
 883          * @param integer $uid          User ID for the signature that we use to fetch data
 884          *
 885          * @return array|false with trusted and valid object data
 886          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 887          * @throws \ImagickException
 888          */
 889         private static function fetchObject(string $object_id, array $object = [], bool $trust_source = false, int $uid = 0)
 890         {
 891                 // By fetching the type we check if the object is complete.
 892                 $type = JsonLD::fetchElement($object, '@type');
 893
 894                 if (!$trust_source || empty($type)) {
 895                         $data = ActivityPub::fetchContent($object_id, $uid);
 896                         if (!empty($data)) {
 897                                 $object = JsonLD::compact($data);
 898                                 Logger::log('Fetched content for ' . $object_id, Logger::DEBUG);
 899                         } else {
 900                                 Logger::log('Empty content for ' . $object_id . ', check if content is available locally.', Logger::DEBUG);
 901
 902                                 $item = Item::selectFirst([], ['uri' => $object_id]);
 903                                 if (!DBA::isResult($item)) {
 904                                         Logger::log('Object with url ' . $object_id . ' was not found locally.', Logger::DEBUG);
 905                                         return false;
 906                                 }
 907                                 Logger::log('Using already stored item for url ' . $object_id, Logger::DEBUG);
 908                                 $data = ActivityPub\Transmitter::createNote($item);
 909                                 $object = JsonLD::compact($data);
 910                         }
 911
 912                         $id = JsonLD::fetchElement($object, '@id');
 913                         if (empty($id)) {
 914                                 Logger::info('Empty id');
 915                                 return false;
 916                         }
 917
 918                         if ($id != $object_id) {
 919                                 Logger::info('Fetched id differs from provided id', ['provided' => $object_id, 'fetched' => $id]);
 920                                 return false;
 921                         }
 922                 } else {
 923                         Logger::log('Using original object for url ' . $object_id, Logger::DEBUG);
 924                 }
 925
 926                 $type = JsonLD::fetchElement($object, '@type');
 927                 if (empty($type)) {
 928                         Logger::info('Empty type');
 929                         return false;
 930                 }
 931
 932                 // We currently don't handle 'pt:CacheFile', but with this step we avoid logging
 933                 if (in_array($type, self::CONTENT_TYPES) || ($type == 'pt:CacheFile')) {
 934                         $object_data = self::processObject($object);
 935
 936                         if (!empty($data)) {
 937                                 $object_data['raw'] = json_encode($data);
 938                         }
 939                         return $object_data;
 940                 }
 941
 942                 if ($type == 'as:Announce') {
 943                         $object_id = JsonLD::fetchElement($object, 'object', '@id');
 944                         if (empty($object_id) || !is_string($object_id)) {
 945                                 return false;
 946                         }
 947                         return self::fetchObject($object_id, [], false, $uid);
 948                 }
 949
 950                 Logger::log('Unhandled object type: ' . $type, Logger::DEBUG);
 951                 return false;
 952         }
 953
 954         /**
 955          * Convert tags from JSON-LD format into a simplified format
 956          *
 957          * @param array $tags Tags in JSON-LD format
 958          *
 959          * @return array with tags in a simplified format
 960          */
 961         private static function processTags(array $tags)
 962         {
 963                 $taglist = [];
 964
 965                 foreach ($tags as $tag) {
 966                         if (empty($tag)) {
 967                                 continue;
 968                         }
 969
 970                         $element = ['type' => str_replace('as:', '', JsonLD::fetchElement($tag, '@type')),
 971                                 'href' => JsonLD::fetchElement($tag, 'as:href', '@id'),
 972                                 'name' => JsonLD::fetchElement($tag, 'as:name', '@value')];
 973
 974                         if (empty($element['type'])) {
 975                                 continue;
 976                         }
 977
 978                         if (empty($element['href'])) {
 979                                 $element['href'] = $element['name'];
 980                         }
 981
 982                         $taglist[] = $element;
 983                 }
 984                 return $taglist;
 985         }
 986
 987         /**
 988          * Convert emojis from JSON-LD format into a simplified format
 989          *
 990          * @param array $emojis
 991          * @return array with emojis in a simplified format
 992          */
 993         private static function processEmojis(array $emojis)
 994         {
 995                 $emojilist = [];
 996
 997                 foreach ($emojis as $emoji) {
 998                         if (empty($emoji) || (JsonLD::fetchElement($emoji, '@type') != 'toot:Emoji') || empty($emoji['as:icon'])) {
 999                                 continue;
1000                         }
1001
1002                         $url = JsonLD::fetchElement($emoji['as:icon'], 'as:url', '@id');
1003                         $element = ['name' => JsonLD::fetchElement($emoji, 'as:name', '@value'),
1004                                 'href' => $url];
1005
1006                         $emojilist[] = $element;
1007                 }
1008
1009                 return $emojilist;
1010         }
1011
1012         /**
1013          * Convert attachments from JSON-LD format into a simplified format
1014          *
1015          * @param array $attachments Attachments in JSON-LD format
1016          *
1017          * @return array Attachments in a simplified format
1018          */
1019         private static function processAttachments(array $attachments)
1020         {
1021                 $attachlist = [];
1022
1023                 // Removes empty values
1024                 $attachments = array_filter($attachments);
1025
1026                 foreach ($attachments as $attachment) {
1027                         switch (JsonLD::fetchElement($attachment, '@type')) {
1028                                 case 'as:Page':
1029                                         $pageUrl = null;
1030                                         $pageImage = null;
1031
1032                                         $urls = JsonLD::fetchElementArray($attachment, 'as:url');
1033                                         foreach ($urls as $url) {
1034                                                 // Single scalar URL case
1035                                                 if (is_string($url)) {
1036                                                         $pageUrl = $url;
1037                                                         continue;
1038                                                 }
1039
1040                                                 $href = JsonLD::fetchElement($url, 'as:href', '@id');
1041                                                 $mediaType = JsonLD::fetchElement($url, 'as:mediaType', '@value');
1042                                                 if (Strings::startsWith($mediaType, 'image')) {
1043                                                         $pageImage = $href;
1044                                                 } else {
1045                                                         $pageUrl = $href;
1046                                                 }
1047                                         }
1048
1049                                         $attachlist[] = [
1050                                                 'type'  => 'link',
1051                                                 'title' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1052                                                 'desc'  => JsonLD::fetchElement($attachment, 'as:summary', '@value'),
1053                                                 'url'   => $pageUrl,
1054                                                 'image' => $pageImage,
1055                                         ];
1056                                         break;
1057                                 case 'as:Link':
1058                                         $attachlist[] = [
1059                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1060                                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType', '@value'),
1061                                                 'name' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1062                                                 'url' => JsonLD::fetchElement($attachment, 'as:href', '@id')
1063                                         ];
1064                                         break;
1065                                 case 'as:Image':
1066                                         $mediaType = JsonLD::fetchElement($attachment, 'as:mediaType', '@value');
1067                                         $imageFullUrl = JsonLD::fetchElement($attachment, 'as:url', '@id');
1068                                         $imagePreviewUrl = null;
1069                                         // Multiple URLs?
1070                                         if (!$imageFullUrl && ($urls = JsonLD::fetchElementArray($attachment, 'as:url'))) {
1071                                                 $imageVariants = [];
1072                                                 $previewVariants = [];
1073                                                 foreach ($urls as $url) {
1074                                                         // Scalar URL, no discrimination possible
1075                                                         if (is_string($url)) {
1076                                                                 $imageFullUrl = $url;
1077                                                                 continue;
1078                                                         }
1079
1080                                                         // Not sure what to do with a different Link media type than the base Image, we skip
1081                                                         if ($mediaType != JsonLD::fetchElement($url, 'as:mediaType', '@value')) {
1082                                                                 continue;
1083                                                         }
1084
1085                                                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1086
1087                                                         // Default URL choice if no discriminating width is provided
1088                                                         $imageFullUrl = $href ?? $imageFullUrl;
1089
1090                                                         $width = intval(JsonLD::fetchElement($url, 'as:width', '@value') ?? 1);
1091
1092                                                         if ($href && $width) {
1093                                                                 $imageVariants[$width] = $href;
1094                                                                 // 632 is the ideal width for full screen frio posts, we compute the absolute distance to it
1095                                                                 $previewVariants[abs(632 - $width)] = $href;
1096                                                         }
1097                                                 }
1098
1099                                                 if ($imageVariants) {
1100                                                         // Taking the maximum size image
1101                                                         ksort($imageVariants);
1102                                                         $imageFullUrl = array_pop($imageVariants);
1103
1104                                                         // Taking the minimum number distance to the target distance
1105                                                         ksort($previewVariants);
1106                                                         $imagePreviewUrl = array_shift($previewVariants);
1107                                                 }
1108
1109                                                 unset($imageVariants);
1110                                                 unset($previewVariants);
1111                                         }
1112
1113                                         $attachlist[] = [
1114                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1115                                                 'mediaType' => $mediaType,
1116                                                 'name'  => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1117                                                 'url'   => $imageFullUrl,
1118                                                 'image' => $imagePreviewUrl !== $imageFullUrl ? $imagePreviewUrl : null,
1119                                         ];
1120                                         break;
1121                                 default:
1122                                         $attachlist[] = [
1123                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1124                                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType', '@value'),
1125                                                 'name' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1126                                                 'url' => JsonLD::fetchElement($attachment, 'as:url', '@id')
1127                                         ];
1128                         }
1129                 }
1130
1131                 return $attachlist;
1132         }
1133
1134         /**
1135          * Fetch the original source or content with the "language" Markdown or HTML
1136          *
1137          * @param array $object
1138          * @param array $object_data
1139          *
1140          * @return array
1141          * @throws \Exception
1142          */
1143         private static function getSource($object, $object_data)
1144         {
1145                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/bbcode');
1146                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1147                 if (!empty($object_data['source'])) {
1148                         return $object_data;
1149                 }
1150
1151                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/markdown');
1152                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1153                 if (!empty($object_data['source'])) {
1154                         $object_data['source'] = Markdown::toBBCode($object_data['source']);
1155                         return $object_data;
1156                 }
1157
1158                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/html');
1159                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1160                 if (!empty($object_data['source'])) {
1161                         $object_data['source'] = HTML::toBBCode($object_data['source']);
1162                         return $object_data;
1163                 }
1164
1165                 return $object_data;
1166         }
1167
1168         /**
1169          * Check if the "as:url" element is an array with multiple links
1170          * This is the case with audio and video posts.
1171          * Then the links are added as attachments
1172          *
1173          * @param array $object      The raw object
1174          * @param array $object_data The parsed object data for later processing
1175          * @return array the object data
1176          */
1177         private static function processAttachmentUrls(array $object, array $object_data) {
1178                 // Check if this is some url with multiple links
1179                 if (empty($object['as:url'])) {
1180                         return $object_data;
1181                 }
1182
1183                 $urls = $object['as:url'];
1184                 $keys = array_keys($urls);
1185                 if (!is_numeric(array_pop($keys))) {
1186                         return $object_data;
1187                 }
1188
1189                 $attachments = [];
1190
1191                 foreach ($urls as $url) {
1192                         if (empty($url['@type']) || ($url['@type'] != 'as:Link')) {
1193                                 continue;
1194                         }
1195
1196                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1197                         if (empty($href)) {
1198                                 continue;
1199                         }
1200
1201                         $mediatype = JsonLD::fetchElement($url, 'as:mediaType');
1202                         if (empty($mediatype)) {
1203                                 continue;
1204                         }
1205
1206                         if ($mediatype == 'text/html') {
1207                                 $object_data['alternate-url'] = $href;
1208                         }
1209
1210                         $filetype = strtolower(substr($mediatype, 0, strpos($mediatype, '/')));
1211
1212                         if ($filetype == 'audio') {
1213                                 $attachments[$filetype] = ['type' => $mediatype, 'url' => $href];
1214                         } elseif ($filetype == 'video') {
1215                                 $height = (int)JsonLD::fetchElement($url, 'as:height', '@value');
1216
1217                                 // We save bandwidth by using a moderate height
1218                                 // Peertube normally uses these heights: 240, 360, 480, 720, 1080
1219                                 if (!empty($attachments[$filetype]['height']) &&
1220                                         (($height > 480) || $height < $attachments[$filetype]['height'])) {
1221                                         continue;
1222                                 }
1223
1224                                 $attachments[$filetype] = ['type' => $mediatype, 'url' => $href, 'height' => $height];
1225                         }
1226                 }
1227
1228                 foreach ($attachments as $type => $attachment) {
1229                         $object_data['attachments'][] = ['type' => $type,
1230                                 'mediaType' => $attachment['type'],
1231                                 'name' => '',
1232                                 'url' => $attachment['url']];
1233                 }
1234                 return $object_data;
1235         }
1236
1237         /**
1238          * Fetches data from the object part of an activity
1239          *
1240          * @param array $object
1241          *
1242          * @return array
1243          * @throws \Exception
1244          */
1245         private static function processObject($object)
1246         {
1247                 if (!JsonLD::fetchElement($object, '@id')) {
1248                         return false;
1249                 }
1250
1251                 $object_data = [];
1252                 $object_data['object_type'] = JsonLD::fetchElement($object, '@type');
1253                 $object_data['id'] = JsonLD::fetchElement($object, '@id');
1254                 $object_data['reply-to-id'] = JsonLD::fetchElement($object, 'as:inReplyTo', '@id');
1255
1256                 // An empty "id" field is translated to "./" by the compactor, so we have to check for this content
1257                 if (empty($object_data['reply-to-id']) || ($object_data['reply-to-id'] == './')) {
1258                         $object_data['reply-to-id'] = $object_data['id'];
1259                 } else {
1260                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
1261                         $replyToId = Item::getURIByLink($object_data['reply-to-id']);
1262                         if (!empty($replyToId) && ($object_data['reply-to-id'] != $replyToId)) {
1263                                 Logger::notice('Fix wrong reply-to', ['received' => $object_data['reply-to-id'], 'correct' => $replyToId]);
1264                                 $object_data['reply-to-id'] = $replyToId;
1265                         }
1266                 }
1267
1268                 $object_data['published'] = JsonLD::fetchElement($object, 'as:published', '@value');
1269                 $object_data['updated'] = JsonLD::fetchElement($object, 'as:updated', '@value');
1270
1271                 if (empty($object_data['updated'])) {
1272                         $object_data['updated'] = $object_data['published'];
1273                 }
1274
1275                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
1276                         $object_data['published'] = $object_data['updated'];
1277                 }
1278
1279                 $actor = JsonLD::fetchElement($object, 'as:attributedTo', '@id');
1280                 if (empty($actor)) {
1281                         $actor = JsonLD::fetchElement($object, 'as:actor', '@id');
1282                 }
1283
1284                 $location = JsonLD::fetchElement($object, 'as:location', 'as:name', '@type', 'as:Place');
1285                 $location = JsonLD::fetchElement($location, 'location', '@value');
1286                 if ($location) {
1287                         // Some AP software allow formatted text in post location, so we run all the text converters we have to boil
1288                         // down to HTML and then finally format to plaintext.
1289                         $location = Markdown::convert($location);
1290                         $location = BBCode::convert($location);
1291                         $location = HTML::toPlaintext($location);
1292                 }
1293
1294                 $object_data['sc:identifier'] = JsonLD::fetchElement($object, 'sc:identifier', '@value');
1295                 $object_data['diaspora:guid'] = JsonLD::fetchElement($object, 'diaspora:guid', '@value');
1296                 $object_data['diaspora:comment'] = JsonLD::fetchElement($object, 'diaspora:comment', '@value');
1297                 $object_data['diaspora:like'] = JsonLD::fetchElement($object, 'diaspora:like', '@value');
1298                 $object_data['actor'] = $object_data['author'] = $actor;
1299                 $object_data['context'] = JsonLD::fetchElement($object, 'as:context', '@id');
1300                 $object_data['conversation'] = JsonLD::fetchElement($object, 'ostatus:conversation', '@id');
1301                 $object_data['sensitive'] = JsonLD::fetchElement($object, 'as:sensitive');
1302                 $object_data['name'] = JsonLD::fetchElement($object, 'as:name', '@value');
1303                 $object_data['summary'] = JsonLD::fetchElement($object, 'as:summary', '@value');
1304                 $object_data['content'] = JsonLD::fetchElement($object, 'as:content', '@value');
1305                 $object_data = self::getSource($object, $object_data);
1306                 $object_data['start-time'] = JsonLD::fetchElement($object, 'as:startTime', '@value');
1307                 $object_data['end-time'] = JsonLD::fetchElement($object, 'as:endTime', '@value');
1308                 $object_data['location'] = $location;
1309                 $object_data['latitude'] = JsonLD::fetchElement($object, 'as:location', 'as:latitude', '@type', 'as:Place');
1310                 $object_data['latitude'] = JsonLD::fetchElement($object_data, 'latitude', '@value');
1311                 $object_data['longitude'] = JsonLD::fetchElement($object, 'as:location', 'as:longitude', '@type', 'as:Place');
1312                 $object_data['longitude'] = JsonLD::fetchElement($object_data, 'longitude', '@value');
1313                 $object_data['attachments'] = self::processAttachments(JsonLD::fetchElementArray($object, 'as:attachment') ?? []);
1314                 $object_data['tags'] = self::processTags(JsonLD::fetchElementArray($object, 'as:tag') ?? []);
1315                 $object_data['emojis'] = self::processEmojis(JsonLD::fetchElementArray($object, 'as:tag', 'toot:Emoji') ?? []);
1316                 $object_data['generator'] = JsonLD::fetchElement($object, 'as:generator', 'as:name', '@type', 'as:Application');
1317                 $object_data['generator'] = JsonLD::fetchElement($object_data, 'generator', '@value');
1318                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'as:url', '@id');
1319
1320                 // Special treatment for Hubzilla links
1321                 if (is_array($object_data['alternate-url'])) {
1322                         $object_data['alternate-url'] = JsonLD::fetchElement($object_data['alternate-url'], 'as:href', '@id');
1323
1324                         if (!is_string($object_data['alternate-url'])) {
1325                                 $object_data['alternate-url'] = JsonLD::fetchElement($object['as:url'], 'as:href', '@id');
1326                         }
1327                 }
1328
1329                 if (in_array($object_data['object_type'], ['as:Audio', 'as:Video'])) {
1330                         $object_data = self::processAttachmentUrls($object, $object_data);
1331                 }
1332
1333                 $receiverdata = self::getReceivers($object, $object_data['actor'], $object_data['tags'], true);
1334                 $receivers = $reception_types = [];
1335                 foreach ($receiverdata as $key => $data) {
1336                         $receivers[$key] = $data['uid'];
1337                         $reception_types[$data['uid']] = $data['type'] ?? 0;
1338                 }
1339
1340                 $object_data['receiver'] = $receivers;
1341                 $object_data['reception_type'] = $reception_types;
1342
1343                 $object_data['unlisted'] = in_array(-1, $object_data['receiver']);
1344                 unset($object_data['receiver']['uid:-1']);
1345
1346                 // Common object data:
1347
1348                 // Unhandled
1349                 // @context, type, actor, signature, mediaType, duration, replies, icon
1350
1351                 // Also missing: (Defined in the standard, but currently unused)
1352                 // audience, preview, endTime, startTime, image
1353
1354                 // Data in Notes:
1355
1356                 // Unhandled
1357                 // contentMap, announcement_count, announcements, context_id, likes, like_count
1358                 // inReplyToStatusId, shares, quoteUrl, statusnetConversationId
1359
1360                 // Data in video:
1361
1362                 // To-Do?
1363                 // category, licence, language, commentsEnabled
1364
1365                 // Unhandled
1366                 // views, waitTranscoding, state, support, subtitleLanguage
1367                 // likes, dislikes, shares, comments
1368
1369                 return $object_data;
1370         }
1371 }