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