src/Protocol/ActivityPub/Receiver.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2010-2022, the Friendica project
   4  *
   5  * @license GNU AGPL version 3 or any later version
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU Affero General Public License as
   9  * published by the Free Software Foundation, either version 3 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU Affero General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Affero General Public License
  18  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  19  *
  20  */
  21
  22 namespace Friendica\Protocol\ActivityPub;
  23
  24 use Friendica\Content\Text\BBCode;
  25 use Friendica\Database\DBA;
  26 use Friendica\Content\Text\HTML;
  27 use Friendica\Content\Text\Markdown;
  28 use Friendica\Core\Logger;
  29 use Friendica\Core\Protocol;
  30 use Friendica\Core\System;
  31 use Friendica\Core\Worker;
  32 use Friendica\DI;
  33 use Friendica\Model\Contact;
  34 use Friendica\Model\APContact;
  35 use Friendica\Model\Item;
  36 use Friendica\Model\Post;
  37 use Friendica\Model\User;
  38 use Friendica\Protocol\Activity;
  39 use Friendica\Protocol\ActivityPub;
  40 use Friendica\Util\DateTimeFormat;
  41 use Friendica\Util\HTTPSignature;
  42 use Friendica\Util\JsonLD;
  43 use Friendica\Util\LDSignature;
  44 use Friendica\Util\Network;
  45 use Friendica\Util\Strings;
  46
  47 /**
  48  * ActivityPub Receiver Protocol class
  49  *
  50  * To-Do:
  51  * @todo Undo Announce
  52  *
  53  * Check what this is meant to do:
  54  * - Add
  55  * - Block
  56  * - Flag
  57  * - Remove
  58  * - Undo Block
  59  */
  60 class Receiver
  61 {
  62         const PUBLIC_COLLECTION = 'as:Public';
  63         const ACCOUNT_TYPES = ['as:Person', 'as:Organization', 'as:Service', 'as:Group', 'as:Application'];
  64         const CONTENT_TYPES = ['as:Note', 'as:Article', 'as:Video', 'as:Image', 'as:Event', 'as:Audio', 'as:Page', 'as:Question'];
  65         const ACTIVITY_TYPES = ['as:Like', 'as:Dislike', 'as:Accept', 'as:Reject', 'as:TentativeAccept'];
  66
  67         const TARGET_UNKNOWN = 0;
  68         const TARGET_TO = 1;
  69         const TARGET_CC = 2;
  70         const TARGET_BTO = 3;
  71         const TARGET_BCC = 4;
  72         const TARGET_FOLLOWER = 5;
  73         const TARGET_ANSWER = 6;
  74         const TARGET_GLOBAL = 7;
  75
  76         const COMPLETION_NONE    = 0;
  77         const COMPLETION_ANNOUCE = 1;
  78         const COMPLETION_RELAY   = 2;
  79         const COMPLETION_MANUAL  = 3;
  80         const COMPLETION_AUTO    = 4;
  81
  82         /**
  83          * Checks incoming message from the inbox
  84          *
  85          * @param string  $body Body string
  86          * @param array   $header Header lines
  87          * @param integer $uid User ID
  88          * @return void
  89          * @throws \Exception
  90          */
  91         public static function processInbox(string $body, array $header, int $uid)
  92         {
  93                 $activity = json_decode($body, true);
  94                 if (empty($activity)) {
  95                         Logger::warning('Invalid body.');
  96                         return;
  97                 }
  98
  99                 $ldactivity = JsonLD::compact($activity);
 100
 101                 $actor = JsonLD::fetchElement($ldactivity, 'as:actor', '@id') ?? '';
 102
 103                 $apcontact = APContact::getByURL($actor);
 104
 105                 if (empty($apcontact)) {
 106                         Logger::notice('Unable to retrieve AP contact for actor - message is discarded', ['actor' => $actor]);
 107                         return;
 108                 } elseif (APContact::isRelay($apcontact)) {
 109                         self::processRelayPost($ldactivity, $actor);
 110                         return;
 111                 } else {
 112                         APContact::unmarkForArchival($apcontact);
 113                 }
 114
 115                 $http_signer = HTTPSignature::getSigner($body, $header);
 116                 if ($http_signer === false) {
 117                         Logger::warning('Invalid HTTP signature, message will be discarded.');
 118                         return;
 119                 } elseif (empty($http_signer)) {
 120                         Logger::info('Signer is a tombstone. The message will be discarded, the signer account is deleted.');
 121                         return;
 122                 } else {
 123                         Logger::info('Valid HTTP signature', ['signer' => $http_signer]);
 124                 }
 125
 126                 $signer = [$http_signer];
 127
 128                 Logger::info('Message for user ' . $uid . ' is from actor ' . $actor);
 129
 130                 if (LDSignature::isSigned($activity)) {
 131                         $ld_signer = LDSignature::getSigner($activity);
 132                         if (empty($ld_signer)) {
 133                                 Logger::info('Invalid JSON-LD signature from ' . $actor);
 134                         } elseif ($ld_signer != $http_signer) {
 135                                 $signer[] = $ld_signer;
 136                         }
 137                         if (!empty($ld_signer && ($actor == $http_signer))) {
 138                                 Logger::info('The HTTP and the JSON-LD signature belong to ' . $ld_signer);
 139                                 $trust_source = true;
 140                         } elseif (!empty($ld_signer)) {
 141                                 Logger::info('JSON-LD signature is signed by ' . $ld_signer);
 142                                 $trust_source = true;
 143                         } elseif ($actor == $http_signer) {
 144                                 Logger::info('Bad JSON-LD signature, but HTTP signer fits the actor.');
 145                                 $trust_source = true;
 146                         } else {
 147                                 Logger::info('Invalid JSON-LD signature and the HTTP signer is different.');
 148                                 $trust_source = false;
 149                         }
 150                 } elseif ($actor == $http_signer) {
 151                         Logger::info('Trusting post without JSON-LD signature, The actor fits the HTTP signer.');
 152                         $trust_source = true;
 153                 } else {
 154                         Logger::info('No JSON-LD signature, different actor.');
 155                         $trust_source = false;
 156                 }
 157
 158                 self::processActivity($ldactivity, $body, $uid, $trust_source, true, $signer, $http_signer);
 159         }
 160
 161         /**
 162          * Process incoming posts from relays
 163          *
 164          * @param array  $activity
 165          * @param string $actor
 166          * @return void
 167          */
 168         private static function processRelayPost(array $activity, string $actor)
 169         {
 170                 $type = JsonLD::fetchElement($activity, '@type');
 171                 if (!$type) {
 172                         Logger::info('Empty type', ['activity' => $activity, 'actor' => $actor]);
 173                         return;
 174                 }
 175
 176                 if ($type != 'as:Announce') {
 177                         Logger::info('Not an announcement', ['activity' => $activity, 'actor' => $actor]);
 178                         return;
 179                 }
 180
 181                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 182                 if (empty($object_id)) {
 183                         Logger::info('No object id found', ['activity' => $activity, 'actor' => $actor]);
 184                         return;
 185                 }
 186
 187                 $contact = Contact::getByURL($actor);
 188                 if (empty($contact)) {
 189                         Logger::info('Relay contact not found', ['actor' => $actor]);
 190                         return;
 191                 }
 192
 193                 if (!in_array($contact['rel'], [Contact::SHARING, Contact::FRIEND])) {
 194                         Logger::notice('Relay is no sharer', ['actor' => $actor]);
 195                         return;
 196                 }
 197
 198                 Logger::info('Got relayed message id', ['id' => $object_id, 'actor' => $actor]);
 199
 200                 $item_id = Item::searchByLink($object_id);
 201                 if ($item_id) {
 202                         Logger::info('Relayed message already exists', ['id' => $object_id, 'item' => $item_id, 'actor' => $actor]);
 203                         return;
 204                 }
 205
 206                 $id = Processor::fetchMissingActivity($object_id, [], $actor, self::COMPLETION_RELAY);
 207                 if (empty($id)) {
 208                         Logger::notice('Relayed message had not been fetched', ['id' => $object_id, 'actor' => $actor]);
 209                         return;
 210                 }
 211         }
 212
 213         /**
 214          * Fetches the object type for a given object id
 215          *
 216          * @param array   $activity
 217          * @param string  $object_id Object ID of the the provided object
 218          * @param integer $uid       User ID
 219          *
 220          * @return string with object type or NULL
 221          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 222          * @throws \ImagickException
 223          */
 224         private static function fetchObjectType(array $activity, string $object_id, int $uid = 0)
 225         {
 226                 if (!empty($activity['as:object'])) {
 227                         $object_type = JsonLD::fetchElement($activity['as:object'], '@type');
 228                         if (!empty($object_type)) {
 229                                 return $object_type;
 230                         }
 231                 }
 232
 233                 if (Post::exists(['uri' => $object_id, 'gravity' => [GRAVITY_PARENT, GRAVITY_COMMENT]])) {
 234                         // We just assume "note" since it doesn't make a difference for the further processing
 235                         return 'as:Note';
 236                 }
 237
 238                 $profile = APContact::getByURL($object_id);
 239                 if (!empty($profile['type'])) {
 240                         APContact::unmarkForArchival($profile);
 241                         return 'as:' . $profile['type'];
 242                 }
 243
 244                 $data = Processor::fetchCachedActivity($object_id, $uid);
 245                 if (!empty($data)) {
 246                         $object = JsonLD::compact($data);
 247                         $type = JsonLD::fetchElement($object, '@type');
 248                         if (!empty($type)) {
 249                                 return $type;
 250                         }
 251                 }
 252
 253                 return null;
 254         }
 255
 256         /**
 257          * Prepare the object array
 258          *
 259          * @param array   $activity     Array with activity data
 260          * @param integer $uid          User ID
 261          * @param boolean $push         Message had been pushed to our system
 262          * @param boolean $trust_source Do we trust the source?
 263          *
 264          * @return array with object data
 265          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 266          * @throws \ImagickException
 267          */
 268         public static function prepareObjectData(array $activity, int $uid, bool $push, bool &$trust_source): array
 269         {
 270                 $id        = JsonLD::fetchElement($activity, '@id');
 271                 $type      = JsonLD::fetchElement($activity, '@type');
 272                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 273
 274                 if (!empty($object_id) && in_array($type, ['as:Create', 'as:Update'])) {
 275                         $fetch_id = $object_id;
 276                 } else {
 277                         $fetch_id = $id;
 278                 }
 279
 280                 if (!empty($activity['as:object'])) {
 281                         $object_type = JsonLD::fetchElement($activity['as:object'], '@type');
 282                 }
 283
 284                 if (!empty($id) && !$trust_source) {
 285                         $fetch_uid = $uid ?: self::getBestUserForActivity($activity);
 286
 287                         $fetched_activity = Processor::fetchCachedActivity($fetch_id, $fetch_uid);
 288                         if (!empty($fetched_activity)) {
 289                                 $object = JsonLD::compact($fetched_activity);
 290
 291                                 $fetched_id   = JsonLD::fetchElement($object, '@id');
 292                                 $fetched_type = JsonLD::fetchElement($object, '@type');
 293
 294                                 if (($fetched_id == $id) && !empty($fetched_type) && ($fetched_type == $type)) {
 295                                         Logger::info('Activity had been fetched successfully', ['id' => $id]);
 296                                         $trust_source = true;
 297                                         $activity = $object;
 298                                 } elseif (($fetched_id == $object_id) && !empty($fetched_type) && ($fetched_type == $object_type)) {
 299                                         Logger::info('Fetched data is the object instead of the activity', ['id' => $id]);
 300                                         $trust_source = true;
 301                                         unset($object['@context']);
 302                                         $activity['as:object'] = $object;
 303                                 } else {
 304                                         Logger::info('Activity id is not equal', ['id' => $id, 'fetched' => $fetched_id]);
 305                                 }
 306                         } else {
 307                                 Logger::info('Activity could not been fetched', ['id' => $id]);
 308                         }
 309                 }
 310
 311                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 312                 if (empty($actor)) {
 313                         Logger::info('Empty actor', ['activity' => $activity]);
 314                         return [];
 315                 }
 316
 317                 $type = JsonLD::fetchElement($activity, '@type');
 318
 319                 // Fetch all receivers from to, cc, bto and bcc
 320                 $receiverdata = self::getReceivers($activity, $actor);
 321                 $receivers = $reception_types = [];
 322                 foreach ($receiverdata as $key => $data) {
 323                         $receivers[$key] = $data['uid'];
 324                         $reception_types[$data['uid']] = $data['type'] ?? self::TARGET_UNKNOWN;
 325                 }
 326
 327                 $urls = self::getReceiverURL($activity);
 328
 329                 // When it is a delivery to a personal inbox we add that user to the receivers
 330                 if (!empty($uid)) {
 331                         $additional = [$uid => $uid];
 332                         $receivers = array_replace($receivers, $additional);
 333                         if (empty($activity['thread-completion']) && (empty($reception_types[$uid]) || in_array($reception_types[$uid], [self::TARGET_UNKNOWN, self::TARGET_FOLLOWER, self::TARGET_ANSWER, self::TARGET_GLOBAL]))) {
 334                                 $reception_types[$uid] = self::TARGET_BCC;
 335                                 $owner = User::getOwnerDataById($uid);
 336                                 if (!empty($owner['url'])) {
 337                                         $urls['as:bcc'][] = $owner['url'];
 338                                 }
 339                         }
 340                 }
 341
 342                 // We possibly need some user to fetch private content,
 343                 // so we fetch one out of the receivers if no uid is provided.
 344                 $fetch_uid = $uid ?: self::getBestUserForActivity($activity);
 345
 346                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 347                 if (empty($object_id)) {
 348                         Logger::info('No object found');
 349                         return [];
 350                 }
 351
 352                 if (!is_string($object_id)) {
 353                         Logger::info('Invalid object id', ['object' => $object_id]);
 354                         return [];
 355                 }
 356
 357                 $object_type = self::fetchObjectType($activity, $object_id, $fetch_uid);
 358
 359                 // Fetch the activity on Lemmy "Announce" messages (announces of activities)
 360                 if (($type == 'as:Announce') && in_array($object_type, array_merge(self::ACTIVITY_TYPES, ['as:Delete', 'as:Undo', 'as:Update']))) {
 361                         $data = Processor::fetchCachedActivity($object_id, $fetch_uid);
 362                         if (!empty($data)) {
 363                                 $type = $object_type;
 364                                 $activity = JsonLD::compact($data);
 365
 366                                 // Some variables need to be refetched since the activity changed
 367                                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 368                                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 369                                 $object_type = self::fetchObjectType($activity, $object_id, $fetch_uid);
 370                         }
 371                 }
 372
 373                 // Any activities on account types must not be altered
 374                 if (in_array($object_type, self::ACCOUNT_TYPES)) {
 375                         $object_data = [];
 376                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 377                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 378                         $object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor', '@id');
 379                         $object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
 380                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 381                         $object_data['push'] = $push;
 382                         if (!$trust_source && ($type == 'as:Delete')) {
 383                                 $apcontact = APContact::getByURL($object_data['object_id'], true);
 384                                 $trust_source = empty($apcontact) || ($apcontact['type'] == 'Tombstone') || $apcontact['suspended'];
 385                         }
 386                 } elseif (in_array($type, ['as:Create', 'as:Update', 'as:Announce', 'as:Invite']) || strpos($type, '#emojiReaction')) {
 387                         // Fetch the content only on activities where this matters
 388                         // We can receive "#emojiReaction" when fetching content from Hubzilla systems
 389                         // Always fetch on "Announce"
 390                         $object_data = self::fetchObject($object_id, $activity['as:object'], $trust_source && ($type != 'as:Announce'), $fetch_uid);
 391                         if (empty($object_data)) {
 392                                 Logger::info("Object data couldn't be processed");
 393                                 return [];
 394                         }
 395
 396                         $object_data['object_id'] = $object_id;
 397
 398                         if ($type == 'as:Announce') {
 399                                 $object_data['push'] = false;
 400                         } else {
 401                                 $object_data['push'] = $push;
 402                         }
 403
 404                         // Test if it is an answer to a mail
 405                         if (DBA::exists('mail', ['uri' => $object_data['reply-to-id']])) {
 406                                 $object_data['directmessage'] = true;
 407                         } else {
 408                                 $object_data['directmessage'] = JsonLD::fetchElement($activity, 'litepub:directMessage');
 409                         }
 410                 } elseif (in_array($type, array_merge(self::ACTIVITY_TYPES, ['as:Follow', 'litepub:EmojiReact', 'as:View'])) && in_array($object_type, self::CONTENT_TYPES)) {
 411                         // Create a mostly empty array out of the activity data (instead of the object).
 412                         // This way we later don't have to check for the existence of each individual array element.
 413                         $object_data = self::processObject($activity);
 414                         $object_data['name'] = $type;
 415                         $object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 416                         $object_data['object_id'] = $object_id;
 417                         $object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
 418                         $object_data['push'] = $push;
 419                 } elseif (in_array($type, ['as:Add', 'as:Remove'])) {
 420                         $object_data = [];
 421                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 422                         $object_data['target_id'] = JsonLD::fetchElement($activity, 'as:target', '@id');
 423                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 424                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 425                         $object_data['object_content'] = JsonLD::fetchElement($activity['as:object'], 'as:content', '@type');
 426                         $object_data['push'] = $push;
 427                 } else {
 428                         $object_data = [];
 429                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 430                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 431                         $object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor', '@id');
 432                         $object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
 433                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 434                         $object_data['push'] = $push;
 435
 436                         // An Undo is done on the object of an object, so we need that type as well
 437                         if (($type == 'as:Undo') && !empty($object_data['object_object'])) {
 438                                 $object_data['object_object_type'] = self::fetchObjectType([], $object_data['object_object'], $fetch_uid);
 439                         }
 440
 441                         if (!$trust_source && ($type == 'as:Delete') && in_array($object_data['object_type'], array_merge(['as:Tombstone', ''], self::CONTENT_TYPES))) {
 442                                 $trust_source = Processor::isActivityGone($object_data['object_id']);
 443                                 if (!$trust_source) {
 444                                         $trust_source = !empty(APContact::getByURL($object_data['object_id'], false));
 445                                 }
 446                         }
 447                 }
 448
 449                 $object_data = self::addActivityFields($object_data, $activity);
 450
 451                 if (empty($object_data['object_type'])) {
 452                         $object_data['object_type'] = $object_type;
 453                 }
 454
 455                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
 456                         if ((empty($object_data['receiver_urls'][$element]) || in_array($element, ['as:bto', 'as:bcc'])) && !empty($urls[$element])) {
 457                                 $object_data['receiver_urls'][$element] = array_unique(array_merge($object_data['receiver_urls'][$element] ?? [], $urls[$element]));
 458                         }
 459                 }
 460
 461                 $object_data['type'] = $type;
 462                 $object_data['actor'] = $actor;
 463                 $object_data['item_receiver'] = $receivers;
 464                 $object_data['receiver'] = array_replace($object_data['receiver'] ?? [], $receivers);
 465                 $object_data['reception_type'] = array_replace($object_data['reception_type'] ?? [], $reception_types);
 466
 467 //              This check here interferes with Hubzilla posts where the author host differs from the host the post was created
 468 //              $author = $object_data['author'] ?? $actor;
 469 //              if (!empty($author) && !empty($object_data['id'])) {
 470 //                      $author_host = parse_url($author, PHP_URL_HOST);
 471 //                      $id_host = parse_url($object_data['id'], PHP_URL_HOST);
 472 //                      if ($author_host == $id_host) {
 473 //                              Logger::info('Valid hosts', ['type' => $type, 'host' => $id_host]);
 474 //                      } else {
 475 //                              Logger::notice('Differing hosts on author and id', ['type' => $type, 'author' => $author_host, 'id' => $id_host]);
 476 //                              $trust_source = false;
 477 //                      }
 478 //              }
 479
 480                 Logger::info('Processing ' . $object_data['type'] . ' ' . $object_data['object_type'] . ' ' . $object_data['id']);
 481
 482                 return $object_data;
 483         }
 484
 485         /**
 486          * Fetches the first user id from the receiver array
 487          *
 488          * @param array $receivers Array with receivers
 489          * @return integer user id;
 490          */
 491         public static function getFirstUserFromReceivers(array $receivers): int
 492         {
 493                 foreach ($receivers as $receiver) {
 494                         if (!empty($receiver)) {
 495                                 return $receiver;
 496                         }
 497                 }
 498                 return 0;
 499         }
 500
 501         /**
 502          * Processes the activity object
 503          *
 504          * @param array      $activity     Array with activity data
 505          * @param string     $body         The unprocessed body
 506          * @param int|null   $uid          User ID
 507          * @param boolean    $trust_source Do we trust the source?
 508          * @param boolean    $push         Message had been pushed to our system
 509          * @param array      $signer       The signer of the post
 510          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 511          * @throws \ImagickException
 512          */
 513         public static function processActivity(array $activity, string $body = '', int $uid = null, bool $trust_source = false, bool $push = false, array $signer = [], string $http_signer = '')
 514         {
 515                 $type = JsonLD::fetchElement($activity, '@type');
 516                 if (!$type) {
 517                         Logger::info('Empty type', ['activity' => $activity]);
 518                         return;
 519                 }
 520
 521                 if (!JsonLD::fetchElement($activity, 'as:object', '@id')) {
 522                         Logger::info('Empty object', ['activity' => $activity]);
 523                         return;
 524                 }
 525
 526                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 527                 if (empty($actor)) {
 528                         Logger::info('Empty actor', ['activity' => $activity]);
 529                         return;
 530                 }
 531
 532                 if (is_array($activity['as:object'])) {
 533                         $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
 534                 } else {
 535                         $attributed_to = '';
 536                 }
 537
 538                 // Test the provided signatures against the actor and "attributedTo"
 539                 if ($trust_source) {
 540                         if (!empty($attributed_to) && !empty($actor)) {
 541                                 $trust_source = (in_array($actor, $signer) && in_array($attributed_to, $signer));
 542                         } else {
 543                                 $trust_source = in_array($actor, $signer);
 544                         }
 545                 }
 546
 547                 // $trust_source is called by reference and is set to true if the content was retrieved successfully
 548                 $object_data = self::prepareObjectData($activity, $uid, $push, $trust_source);
 549                 if (empty($object_data)) {
 550                         Logger::info('No object data found', ['activity' => $activity]);
 551                         return;
 552                 }
 553
 554                 // Lemmy is announcing activities.
 555                 // We are changing the announces into regular activities.
 556                 if (($type == 'as:Announce') && in_array($object_data['type'] ?? '', array_merge(self::ACTIVITY_TYPES, ['as:Delete', 'as:Undo', 'as:Update']))) {
 557                         $type = $object_data['type'];
 558                 }
 559
 560                 if (!empty($body) && empty($object_data['raw'])) {
 561                         $object_data['raw'] = $body;
 562                 }
 563
 564                 // Internal flag for thread completion. See Processor.php
 565                 if (!empty($activity['thread-completion'])) {
 566                         $object_data['thread-completion'] = $activity['thread-completion'];
 567                 }
 568
 569                 if (!empty($activity['completion-mode'])) {
 570                         $object_data['completion-mode'] = $activity['completion-mode'];
 571                 }
 572
 573                 if (!empty($activity['thread-children-type'])) {
 574                         $object_data['thread-children-type'] = $activity['thread-children-type'];
 575                 }
 576
 577                 // Internal flag for posts that arrived via relay
 578                 if (!empty($activity['from-relay'])) {
 579                         $object_data['from-relay'] = $activity['from-relay'];
 580                 }
 581
 582                 if ($type == 'as:Announce') {
 583                         $object_data['object_activity'] = $activity;
 584                 }
 585
 586                 if ($trust_source || DI::config()->get('debug', 'ap_inbox_store_untrusted')) {
 587                         $object_data = Queue::add($object_data, $type, $uid, $http_signer, $push, $trust_source);
 588                 }
 589
 590                 if (!$trust_source) {
 591                         Logger::info('Activity trust could not be achieved.',  ['id' => $object_data['object_id'], 'type' => $type, 'signer' => $signer, 'actor' => $actor, 'attributedTo' => $attributed_to]);
 592                         return;
 593                 }
 594
 595                 if (!empty($object_data['entry-id']) && DI::config()->get('system', 'decoupled_receiver') && ($push || ($activity['completion-mode'] == self::COMPLETION_RELAY))) {
 596                         // We delay by 5 seconds to allow to accumulate all receivers
 597                         $delayed = date(DateTimeFormat::MYSQL, time() + 5);
 598                         Logger::debug('Initiate processing', ['id' => $object_data['entry-id'], 'uri' => $object_data['object_id']]);
 599                         Worker::add(['priority' => PRIORITY_HIGH, 'delayed' => $delayed], 'ProcessQueue', $object_data['entry-id']);
 600                         return;
 601                 }
 602
 603                 if (!empty($activity['recursion-depth'])) {
 604                         $object_data['recursion-depth'] = $activity['recursion-depth'];
 605                 }
 606
 607                 if (in_array('as:Question', [$object_data['object_type'] ?? '', $object_data['object_object_type'] ?? ''])) {
 608                         self::storeUnhandledActivity(false, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 609                 }
 610
 611                 if (!self::routeActivities($object_data, $type, $push)) {
 612                         self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 613                         Queue::remove($object_data);
 614                 }
 615         }
 616
 617         /**
 618          * Route activities
 619          *
 620          * @param array   $object_data
 621          * @param string  $type
 622          * @param boolean $push
 623          *
 624          * @return boolean Could the activity be routed?
 625          */
 626         public static function routeActivities(array $object_data, string $type, bool $push): bool
 627         {
 628                 $activity = $object_data['object_activity']     ?? [];
 629
 630                 switch ($type) {
 631                         case 'as:Create':
 632                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 633                                         $item = ActivityPub\Processor::createItem($object_data);
 634                                         ActivityPub\Processor::postItem($object_data, $item);
 635                                 } elseif (in_array($object_data['object_type'], ['pt:CacheFile'])) {
 636                                         // Unhandled Peertube activity
 637                                         Queue::remove($object_data);
 638                                 } else {
 639                                         return false;
 640                                 }
 641                                 break;
 642
 643                         case 'as:Invite':
 644                                 if (in_array($object_data['object_type'], ['as:Event'])) {
 645                                         $item = ActivityPub\Processor::createItem($object_data);
 646                                         ActivityPub\Processor::postItem($object_data, $item);
 647                                 } else {
 648                                         return false;
 649                                 }
 650                                 break;
 651
 652                         case 'as:Add':
 653                                 if ($object_data['object_type'] == 'as:tag') {
 654                                         ActivityPub\Processor::addTag($object_data);
 655                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 656                                         ActivityPub\Processor::addToFeaturedCollection($object_data);
 657                                 } elseif ($object_data['object_type'] == '') {
 658                                         // The object type couldn't be determined. We don't have it and we can't fetch it. We ignore this activity.
 659                                         Queue::remove($object_data);
 660                                 } else {
 661                                         return false;
 662                                 }
 663                                 break;
 664
 665                         case 'as:Announce':
 666                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 667                                         $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 668                                         $object_data['thread-completion'] = Contact::getIdForURL($actor);
 669                                         $object_data['completion-mode']   = self::COMPLETION_ANNOUCE;
 670
 671                                         $item = ActivityPub\Processor::createItem($object_data);
 672                                         if (empty($item)) {
 673                                                 return false;
 674                                         }
 675
 676                                         $item['post-reason'] = Item::PR_ANNOUNCEMENT;
 677                                         ActivityPub\Processor::postItem($object_data, $item);
 678
 679                                         if (!empty($activity)) {
 680                                                 $announce_object_data = self::processObject($activity);
 681                                                 $announce_object_data['name'] = $type;
 682                                                 $announce_object_data['author'] = $actor;
 683                                                 $announce_object_data['object_id'] = $object_data['object_id'];
 684                                                 $announce_object_data['object_type'] = $object_data['object_type'];
 685                                                 $announce_object_data['push'] = $push;
 686
 687                                                 if (!empty($object_data['raw'])) {
 688                                                         $announce_object_data['raw'] = $object_data['raw'];
 689                                                 }
 690                                                 if (!empty($object_data['raw-object'])) {
 691                                                         $announce_object_data['raw-object'] = $object_data['raw-object'];
 692                                                 }
 693                                                 ActivityPub\Processor::createActivity($announce_object_data, Activity::ANNOUNCE);
 694                                         }
 695                                 } else {
 696                                         return false;
 697                                 }
 698                                 break;
 699
 700                         case 'as:Like':
 701                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 702                                         ActivityPub\Processor::createActivity($object_data, Activity::LIKE);
 703                                 } elseif ($object_data['object_type'] == '') {
 704                                         // The object type couldn't be determined. We don't have it and we can't fetch it. We ignore this activity.
 705                                         Queue::remove($object_data);
 706                                 } else {
 707                                         return false;
 708                                 }
 709                                 break;
 710
 711                         case 'as:Dislike':
 712                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 713                                         ActivityPub\Processor::createActivity($object_data, Activity::DISLIKE);
 714                                 } elseif ($object_data['object_type'] == '') {
 715                                         // The object type couldn't be determined. We don't have it and we can't fetch it. We ignore this activity.
 716                                         Queue::remove($object_data);
 717                                 } else {
 718                                         return false;
 719                                 }
 720                                 break;
 721
 722                         case 'as:TentativeAccept':
 723                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 724                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDMAYBE);
 725                                 } else {
 726                                         return false;
 727                                 }
 728                                 break;
 729
 730                         case 'as:Update':
 731                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 732                                         ActivityPub\Processor::updateItem($object_data);
 733                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 734                                         ActivityPub\Processor::updatePerson($object_data);
 735                                 } elseif (in_array($object_data['object_type'], ['pt:CacheFile'])) {
 736                                         // Unhandled Peertube activity
 737                                         Queue::remove($object_data);
 738                                 } else {
 739                                         return false;
 740                                 }
 741                                 break;
 742
 743                         case 'as:Delete':
 744                                 if (in_array($object_data['object_type'], array_merge(['as:Tombstone'], self::CONTENT_TYPES))) {
 745                                         ActivityPub\Processor::deleteItem($object_data);
 746                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 747                                         ActivityPub\Processor::deletePerson($object_data);
 748                                 } elseif ($object_data['object_type'] == '') {
 749                                         // The object type couldn't be determined. Most likely we don't have it here. We ignore this activity.
 750                                         Queue::remove($object_data);
 751                                 } else {
 752                                         return false;
 753                                 }
 754                                 break;
 755
 756                         case 'as:Block':
 757                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 758                                         ActivityPub\Processor::blockAccount($object_data);
 759                                 } else {
 760                                         return false;
 761                                 }
 762                                 break;
 763
 764                         case 'as:Remove':
 765                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 766                                         ActivityPub\Processor::removeFromFeaturedCollection($object_data);
 767                                 } elseif ($object_data['object_type'] == '') {
 768                                         // The object type couldn't be determined. We don't have it and we can't fetch it. We ignore this activity.
 769                                         Queue::remove($object_data);
 770                                 } else {
 771                                         return false;
 772                                 }
 773                                 break;
 774
 775                         case 'as:Follow':
 776                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 777                                         ActivityPub\Processor::followUser($object_data);
 778                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 779                                         $object_data['reply-to-id'] = $object_data['object_id'];
 780                                         ActivityPub\Processor::createActivity($object_data, Activity::FOLLOW);
 781                                 } else {
 782                                         return false;
 783                                 }
 784                                 break;
 785
 786                         case 'as:Accept':
 787                                 if ($object_data['object_type'] == 'as:Follow') {
 788                                         ActivityPub\Processor::acceptFollowUser($object_data);
 789                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 790                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTEND);
 791                                 } else {
 792                                         return false;
 793                                 }
 794                                 break;
 795
 796                         case 'as:Reject':
 797                                 if ($object_data['object_type'] == 'as:Follow') {
 798                                         ActivityPub\Processor::rejectFollowUser($object_data);
 799                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 800                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDNO);
 801                                 } else {
 802                                         return false;
 803                                 }
 804                                 break;
 805
 806                         case 'as:Undo':
 807                                 if (($object_data['object_type'] == 'as:Follow') &&
 808                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 809                                         ActivityPub\Processor::undoFollowUser($object_data);
 810                                 } elseif (($object_data['object_type'] == 'as:Follow') &&
 811                                         in_array($object_data['object_object_type'], self::CONTENT_TYPES)) {
 812                                         ActivityPub\Processor::undoActivity($object_data);
 813                                 } elseif (($object_data['object_type'] == 'as:Accept') &&
 814                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 815                                         ActivityPub\Processor::rejectFollowUser($object_data);
 816                                 } elseif (($object_data['object_type'] == 'as:Block') &&
 817                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 818                                         ActivityPub\Processor::unblockAccount($object_data);
 819                                 } elseif (in_array($object_data['object_type'], array_merge(self::ACTIVITY_TYPES, ['as:Announce'])) &&
 820                                         in_array($object_data['object_object_type'], array_merge(['as:Tombstone'], self::CONTENT_TYPES))) {
 821                                         ActivityPub\Processor::undoActivity($object_data);
 822                                 } elseif (in_array($object_data['object_type'], array_merge(self::ACTIVITY_TYPES, ['as:Announce', 'as:Create', ''])) &&
 823                                         empty($object_data['object_object_type'])) {
 824                                         // We cannot detect the target object. So we can ignore it.
 825                                         Queue::remove($object_data);
 826                                 } elseif (in_array($object_data['object_type'], ['as:Create']) &&
 827                                         in_array($object_data['object_object_type'], ['pt:CacheFile'])) {
 828                                         // Unhandled Peertube activity
 829                                         Queue::remove($object_data);
 830                                 } else {
 831                                         return false;
 832                                 }
 833                                 break;
 834
 835                         case 'as:View':
 836                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 837                                         ActivityPub\Processor::createActivity($object_data, Activity::VIEW);
 838                                 } elseif ($object_data['object_type'] == '') {
 839                                         // The object type couldn't be determined. Most likely we don't have it here. We ignore this activity.
 840                                         Queue::remove($object_data);
 841                                 } else {
 842                                         return false;
 843                                 }
 844                                 break;
 845
 846                         case 'litepub:EmojiReact':
 847                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 848                                         ActivityPub\Processor::createActivity($object_data, Activity::EMOJIREACT);
 849                                 } elseif ($object_data['object_type'] == '') {
 850                                         // The object type couldn't be determined. We don't have it and we can't fetch it. We ignore this activity.
 851                                         Queue::remove($object_data);
 852                                 } else {
 853                                         return false;
 854                                 }
 855                                 break;
 856
 857                         default:
 858                                 Logger::info('Unknown activity: ' . $type . ' ' . $object_data['object_type']);
 859                                 return false;
 860                 }
 861                 return true;
 862         }
 863
 864         /**
 865          * Stores unhandled or unknown Activities as a file
 866          *
 867          * @param boolean $unknown      "true" if the activity is unknown, "false" if it is unhandled
 868          * @param string  $type         Activity type
 869          * @param array   $object_data  Preprocessed array that is generated out of the received activity
 870          * @param array   $activity     Array with activity data
 871          * @param string  $body         The unprocessed body
 872          * @param integer $uid          User ID
 873          * @param boolean $trust_source Do we trust the source?
 874          * @param boolean $push         Message had been pushed to our system
 875          * @param array   $signer       The signer of the post
 876          * @return void
 877          */
 878         private static function storeUnhandledActivity(bool $unknown, string $type, array $object_data, array $activity, string $body = '', int $uid = null, bool $trust_source = false, bool $push = false, array $signer = [])
 879         {
 880                 if (!DI::config()->get('debug', 'ap_log_unknown')) {
 881                         return;
 882                 }
 883
 884                 $file = ($unknown  ? 'unknown-' : 'unhandled-') . str_replace(':', '-', $type) . '-';
 885
 886                 if (!empty($object_data['object_type'])) {
 887                         $file .= str_replace(':', '-', $object_data['object_type']) . '-';
 888                 }
 889
 890                 if (!empty($object_data['object_object_type'])) {
 891                         $file .= str_replace(':', '-', $object_data['object_object_type']) . '-';
 892                 }
 893
 894                 $tempfile = tempnam(System::getTempPath(), $file);
 895                 file_put_contents($tempfile, json_encode(['activity' => $activity, 'body' => $body, 'uid' => $uid, 'trust_source' => $trust_source, 'push' => $push, 'signer' => $signer, 'object_data' => $object_data], JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE | JSON_PRETTY_PRINT));
 896                 Logger::notice('Unknown activity stored', ['type' => $type, 'object_type' => $object_data['object_type'], $object_data['object_object_type'] ?? '', 'file' => $tempfile]);
 897         }
 898
 899         /**
 900          * Fetch a user id from an activity array
 901          *
 902          * @param array  $activity
 903          * @param string $actor
 904          *
 905          * @return int   user id
 906          */
 907         public static function getBestUserForActivity(array $activity): int
 908         {
 909                 $uid = 0;
 910                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id') ?? '';
 911
 912                 $receivers = self::getReceivers($activity, $actor);
 913                 foreach ($receivers as $receiver) {
 914                         if ($receiver['type'] == self::TARGET_GLOBAL) {
 915                                 return 0;
 916                         }
 917                         if (empty($uid) || ($receiver['type'] == self::TARGET_TO)) {
 918                                 $uid = $receiver['uid'];
 919                         }
 920                 }
 921
 922                 // When we haven't found any user yet, we just chose a user who most likely could have access to the content
 923                 if (empty($uid)) {
 924                         $contact = Contact::selectFirst(['uid'], ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND]]);
 925                         if (!empty($contact['uid'])) {
 926                                 $uid = $contact['uid'];
 927                         }
 928                 }
 929
 930                 return $uid;
 931         }
 932
 933         // @TODO Missing documentation
 934         public static function getReceiverURL(array $activity): array
 935         {
 936                 $urls = [];
 937
 938                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
 939                         $receiver_list = JsonLD::fetchElementArray($activity, $element, '@id');
 940                         if (empty($receiver_list)) {
 941                                 continue;
 942                         }
 943
 944                         foreach ($receiver_list as $receiver) {
 945                                 if ($receiver == self::PUBLIC_COLLECTION) {
 946                                         $receiver = ActivityPub::PUBLIC_COLLECTION;
 947                                 }
 948                                 $urls[$element][] = $receiver;
 949                         }
 950                 }
 951
 952                 return $urls;
 953         }
 954
 955         /**
 956          * Fetch the receiver list from an activity array
 957          *
 958          * @param array   $activity
 959          * @param string  $actor
 960          * @param array   $tags
 961          * @param boolean $fetch_unlisted
 962          *
 963          * @return array with receivers (user id)
 964          * @throws \Exception
 965          */
 966         private static function getReceivers(array $activity, string $actor, array $tags = [], bool $fetch_unlisted = false): array
 967         {
 968                 $reply = $receivers = $profile = [];
 969
 970                 // When it is an answer, we inherite the receivers from the parent
 971                 $replyto = JsonLD::fetchElement($activity, 'as:inReplyTo', '@id');
 972                 if (!empty($replyto)) {
 973                         $reply = [$replyto];
 974
 975                         // Fix possibly wrong item URI (could be an answer to a plink uri)
 976                         $fixedReplyTo = Item::getURIByLink($replyto);
 977                         if (!empty($fixedReplyTo)) {
 978                                 $reply[] = $fixedReplyTo;
 979                         }
 980                 }
 981
 982                 // Fetch all posts that refer to the object id
 983                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 984                 if (!empty($object_id)) {
 985                         $reply[] = $object_id;
 986                 }
 987
 988                 if (!empty($reply)) {
 989                         $parents = Post::select(['uid'], DBA::mergeConditions(['uri' => $reply], ["`uid` != ?", 0]));
 990                         while ($parent = Post::fetch($parents)) {
 991                                 $receivers[$parent['uid']] = ['uid' => $parent['uid'], 'type' => self::TARGET_ANSWER];
 992                         }
 993                         DBA::close($parents);
 994                 }
 995
 996                 if (!empty($actor)) {
 997                         $profile   = APContact::getByURL($actor);
 998                         $followers = $profile['followers'] ?? '';
 999                         $is_forum  = ($actor['type'] ?? '') == 'Group';
1000                         Logger::info('Got actor and followers', ['actor' => $actor, 'followers' => $followers]);
1001                 } else {
1002                         Logger::info('Empty actor', ['activity' => $activity]);
1003                         $followers = '';
1004                         $is_forum  = false;
1005                 }
1006
1007                 // We have to prevent false follower assumptions upon thread completions
1008                 $follower_target = empty($activity['thread-completion']) ? self::TARGET_FOLLOWER : self::TARGET_UNKNOWN;
1009
1010                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
1011                         $receiver_list = JsonLD::fetchElementArray($activity, $element, '@id');
1012                         if (empty($receiver_list)) {
1013                                 continue;
1014                         }
1015
1016                         foreach ($receiver_list as $receiver) {
1017                                 if ($receiver == self::PUBLIC_COLLECTION) {
1018                                         $receivers[0] = ['uid' => 0, 'type' => self::TARGET_GLOBAL];
1019                                 }
1020
1021                                 // Add receiver "-1" for unlisted posts
1022                                 if ($fetch_unlisted && ($receiver == self::PUBLIC_COLLECTION) && ($element == 'as:cc')) {
1023                                         $receivers[-1] = ['uid' => -1, 'type' => self::TARGET_GLOBAL];
1024                                 }
1025
1026                                 // Fetch the receivers for the public and the followers collection
1027                                 if ((($receiver == $followers) || (($receiver == self::PUBLIC_COLLECTION) && !$is_forum)) && !empty($actor)) {
1028                                         $receivers = self::getReceiverForActor($actor, $tags, $receivers, $follower_target, $profile);
1029                                         continue;
1030                                 }
1031
1032                                 // Fetching all directly addressed receivers
1033                                 $condition = ['self' => true, 'nurl' => Strings::normaliseLink($receiver)];
1034                                 $contact = DBA::selectFirst('contact', ['uid', 'contact-type'], $condition);
1035                                 if (!DBA::isResult($contact)) {
1036                                         continue;
1037                                 }
1038
1039                                 // Check if the potential receiver is following the actor
1040                                 // Exception: The receiver is targetted via "to" or this is a comment
1041                                 if ((($element != 'as:to') && empty($replyto)) || ($contact['contact-type'] == Contact::TYPE_COMMUNITY)) {
1042                                         $networks = Protocol::FEDERATED;
1043                                         $condition = ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
1044                                                 'network' => $networks, 'archive' => false, 'pending' => false, 'uid' => $contact['uid']];
1045
1046                                         // Forum posts are only accepted from forum contacts
1047                                         if ($contact['contact-type'] == Contact::TYPE_COMMUNITY) {
1048                                                 $condition['rel'] = [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER];
1049                                         }
1050
1051                                         if (!DBA::exists('contact', $condition)) {
1052                                                 continue;
1053                                         }
1054                                 }
1055
1056                                 $type = $receivers[$contact['uid']]['type'] ?? self::TARGET_UNKNOWN;
1057                                 if (in_array($type, [self::TARGET_UNKNOWN, self::TARGET_FOLLOWER, self::TARGET_ANSWER, self::TARGET_GLOBAL])) {
1058                                         switch ($element) {
1059                                                 case 'as:to':
1060                                                         $type = self::TARGET_TO;
1061                                                         break;
1062                                                 case 'as:cc':
1063                                                         $type = self::TARGET_CC;
1064                                                         break;
1065                                                 case 'as:bto':
1066                                                         $type = self::TARGET_BTO;
1067                                                         break;
1068                                                 case 'as:bcc':
1069                                                         $type = self::TARGET_BCC;
1070                                                         break;
1071                                         }
1072
1073                                         $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $type];
1074                                 }
1075                         }
1076                 }
1077
1078                 self::switchContacts($receivers, $actor);
1079
1080                 return $receivers;
1081         }
1082
1083         /**
1084          * Fetch the receiver list of a given actor
1085          *
1086          * @param string  $actor
1087          * @param array   $tags
1088          * @param array   $receivers
1089          * @param integer $target_type
1090          * @param array   $profile
1091          *
1092          * @return array with receivers (user id)
1093          * @throws \Exception
1094          */
1095         private static function getReceiverForActor(string $actor, array $tags, array $receivers, int $target_type, array $profile): array
1096         {
1097                 $basecondition = ['rel' => [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER],
1098                         'network' => Protocol::FEDERATED, 'archive' => false, 'pending' => false];
1099
1100                 if (!empty($profile['uri-id'])) {
1101                         $condition = DBA::mergeConditions($basecondition, ["`uri-id` = ? AND `uid` != ?", $profile['uri-id'], 0]);
1102                         $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
1103                         while ($contact = DBA::fetch($contacts)) {
1104                                 if (empty($receivers[$contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
1105                                         $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $target_type];
1106                                 }
1107                         }
1108                         DBA::close($contacts);
1109                 } else {
1110                         // This part will only be called while post update 1426 wasn't finished
1111                         $condition = DBA::mergeConditions($basecondition, ["`nurl` = ? AND `uid` != ?", Strings::normaliseLink($actor), 0]);
1112                         $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
1113                         while ($contact = DBA::fetch($contacts)) {
1114                                 if (empty($receivers[$contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
1115                                         $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $target_type];
1116                                 }
1117                         }
1118                         DBA::close($contacts);
1119
1120                         // The queries are split because of performance issues
1121                         $condition = DBA::mergeConditions($basecondition, ["`alias` IN (?, ?) AND `uid` != ?", Strings::normaliseLink($actor), $actor, 0]);
1122                         $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
1123                         while ($contact = DBA::fetch($contacts)) {
1124                                 if (empty($receivers[$contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
1125                                         $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $target_type];
1126                                 }
1127                         }
1128                         DBA::close($contacts);
1129                 }
1130                 return $receivers;
1131         }
1132
1133         /**
1134          * Tests if the contact is a valid receiver for this actor
1135          *
1136          * @param array  $contact
1137          * @param array  $tags
1138          *
1139          * @return bool with receivers (user id)
1140          * @throws \Exception
1141          */
1142         private static function isValidReceiverForActor(array $contact, array $tags): bool
1143         {
1144                 // Are we following the contact? Then this is a valid receiver
1145                 if (in_array($contact['rel'], [Contact::SHARING, Contact::FRIEND])) {
1146                         return true;
1147                 }
1148
1149                 // When the possible receiver isn't a community, then it is no valid receiver
1150                 $owner = User::getOwnerDataById($contact['uid']);
1151                 if (empty($owner) || ($owner['contact-type'] != Contact::TYPE_COMMUNITY)) {
1152                         return false;
1153                 }
1154
1155                 // Is the community account tagged?
1156                 foreach ($tags as $tag) {
1157                         if ($tag['type'] != 'Mention') {
1158                                 continue;
1159                         }
1160
1161                         if (Strings::compareLink($tag['href'], $owner['url'])) {
1162                                 return true;
1163                         }
1164                 }
1165
1166                 return false;
1167         }
1168
1169         /**
1170          * Switches existing contacts to ActivityPub
1171          *
1172          * @param integer $cid Contact ID
1173          * @param integer $uid User ID
1174          * @param string  $url Profile URL
1175          * @return void
1176          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1177          * @throws \ImagickException
1178          */
1179         public static function switchContact(int $cid, int $uid, string $url)
1180         {
1181                 if (DBA::exists('contact', ['id' => $cid, 'network' => Protocol::ACTIVITYPUB])) {
1182                         Logger::info('Contact is already ActivityPub', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
1183                         return;
1184                 }
1185
1186                 if (Contact::updateFromProbe($cid)) {
1187                         Logger::info('Update was successful', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
1188                 }
1189
1190                 // Send a new follow request to be sure that the connection still exists
1191                 if (($uid != 0) && DBA::exists('contact', ['id' => $cid, 'rel' => [Contact::SHARING, Contact::FRIEND], 'network' => Protocol::ACTIVITYPUB])) {
1192                         Logger::info('Contact had been switched to ActivityPub. Sending a new follow request.', ['uid' => $uid, 'url' => $url]);
1193                         ActivityPub\Transmitter::sendActivity('Follow', $url, $uid);
1194                 }
1195         }
1196
1197         /**
1198          * @TODO Fix documentation and type-hints
1199          *
1200          * @param $receivers
1201          * @param $actor
1202          * @return void
1203          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1204          * @throws \ImagickException
1205          */
1206         private static function switchContacts($receivers, $actor)
1207         {
1208                 if (empty($actor)) {
1209                         return;
1210                 }
1211
1212                 foreach ($receivers as $receiver) {
1213                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver['uid'], 'network' => Protocol::OSTATUS, 'nurl' => Strings::normaliseLink($actor)]);
1214                         if (DBA::isResult($contact)) {
1215                                 self::switchContact($contact['id'], $receiver['uid'], $actor);
1216                         }
1217
1218                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver['uid'], 'network' => Protocol::OSTATUS, 'alias' => [Strings::normaliseLink($actor), $actor]]);
1219                         if (DBA::isResult($contact)) {
1220                                 self::switchContact($contact['id'], $receiver['uid'], $actor);
1221                         }
1222                 }
1223         }
1224
1225         /**
1226          * @TODO Fix documentation and type-hints
1227          *
1228          * @param       $object_data
1229          * @param array $activity
1230          *
1231          * @return mixed
1232          */
1233         private static function addActivityFields($object_data, array $activity)
1234         {
1235                 if (!empty($activity['published']) && empty($object_data['published'])) {
1236                         $object_data['published'] = JsonLD::fetchElement($activity, 'as:published', '@value');
1237                 }
1238
1239                 if (!empty($activity['diaspora:guid']) && empty($object_data['diaspora:guid'])) {
1240                         $object_data['diaspora:guid'] = JsonLD::fetchElement($activity, 'diaspora:guid', '@value');
1241                 }
1242
1243                 $object_data['service'] = JsonLD::fetchElement($activity, 'as:instrument', 'as:name', '@type', 'as:Service');
1244                 $object_data['service'] = JsonLD::fetchElement($object_data, 'service', '@value');
1245
1246                 if (!empty($object_data['object_id'])) {
1247                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
1248                         $objectId = Item::getURIByLink($object_data['object_id']);
1249                         if (!empty($objectId) && ($object_data['object_id'] != $objectId)) {
1250                                 Logger::notice('Fix wrong object-id', ['received' => $object_data['object_id'], 'correct' => $objectId]);
1251                                 $object_data['object_id'] = $objectId;
1252                         }
1253                 }
1254
1255                 return $object_data;
1256         }
1257
1258         /**
1259          * Fetches the object data from external ressources if needed
1260          *
1261          * @param string  $object_id    Object ID of the the provided object
1262          * @param array   $object       The provided object array
1263          * @param boolean $trust_source Do we trust the provided object?
1264          * @param integer $uid          User ID for the signature that we use to fetch data
1265          *
1266          * @return array|false with trusted and valid object data
1267          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1268          * @throws \ImagickException
1269          */
1270         private static function fetchObject(string $object_id, array $object = [], bool $trust_source = false, int $uid = 0)
1271         {
1272                 // By fetching the type we check if the object is complete.
1273                 $type = JsonLD::fetchElement($object, '@type');
1274
1275                 if (!$trust_source || empty($type)) {
1276                         $data = Processor::fetchCachedActivity($object_id, $uid);
1277                         if (!empty($data)) {
1278                                 $object = JsonLD::compact($data);
1279                                 Logger::info('Fetched content for ' . $object_id);
1280                         } else {
1281                                 Logger::info('Empty content for ' . $object_id . ', check if content is available locally.');
1282
1283                                 $item = Post::selectFirst(Item::DELIVER_FIELDLIST, ['uri' => $object_id]);
1284                                 if (!DBA::isResult($item)) {
1285                                         Logger::info('Object with url ' . $object_id . ' was not found locally.');
1286                                         return false;
1287                                 }
1288                                 Logger::info('Using already stored item for url ' . $object_id);
1289                                 $data = ActivityPub\Transmitter::createNote($item);
1290                                 $object = JsonLD::compact($data);
1291                         }
1292
1293                         $id = JsonLD::fetchElement($object, '@id');
1294                         if (empty($id)) {
1295                                 Logger::info('Empty id');
1296                                 return false;
1297                         }
1298
1299                         if ($id != $object_id) {
1300                                 Logger::info('Fetched id differs from provided id', ['provided' => $object_id, 'fetched' => $id]);
1301                                 return false;
1302                         }
1303                 } else {
1304                         Logger::info('Using original object for url ' . $object_id);
1305                 }
1306
1307                 $type = JsonLD::fetchElement($object, '@type');
1308                 if (empty($type)) {
1309                         Logger::info('Empty type');
1310                         return false;
1311                 }
1312
1313                 // Lemmy is resharing "create" activities instead of content
1314                 // We fetch the content from the activity.
1315                 if (in_array($type, ['as:Create'])) {
1316                         $object = $object['as:object'];
1317                         $type = JsonLD::fetchElement($object, '@type');
1318                         if (empty($type)) {
1319                                 Logger::info('Empty type');
1320                                 return false;
1321                         }
1322                         $object_data = self::processObject($object);
1323                 }
1324
1325                 // We currently don't handle 'pt:CacheFile', but with this step we avoid logging
1326                 if (in_array($type, self::CONTENT_TYPES) || ($type == 'pt:CacheFile')) {
1327                         $object_data = self::processObject($object);
1328
1329                         if (!empty($data)) {
1330                                 $object_data['raw-object'] = json_encode($data);
1331                         }
1332                         return $object_data;
1333                 }
1334
1335                 if ($type == 'as:Announce') {
1336                         $object_id = JsonLD::fetchElement($object, 'object', '@id');
1337                         if (empty($object_id) || !is_string($object_id)) {
1338                                 return false;
1339                         }
1340                         return self::fetchObject($object_id, [], false, $uid);
1341                 }
1342
1343                 Logger::info('Unhandled object type: ' . $type);
1344                 return false;
1345         }
1346
1347         /**
1348          * Converts the language element (Used by Peertube)
1349          *
1350          * @param array $languages
1351          * @return array Languages
1352          */
1353         public static function processLanguages(array $languages): array
1354         {
1355                 if (empty($languages)) {
1356                         return [];
1357                 }
1358
1359                 $language_list = [];
1360
1361                 foreach ($languages as $language) {
1362                         if (!empty($language['_:identifier']) && !empty($language['as:name'])) {
1363                                 $language_list[$language['_:identifier']] = $language['as:name'];
1364                         }
1365                 }
1366                 return $language_list;
1367         }
1368
1369         /**
1370          * Convert tags from JSON-LD format into a simplified format
1371          *
1372          * @param array $tags Tags in JSON-LD format
1373          *
1374          * @return array with tags in a simplified format
1375          */
1376         public static function processTags(array $tags): array
1377         {
1378                 $taglist = [];
1379
1380                 foreach ($tags as $tag) {
1381                         if (empty($tag)) {
1382                                 continue;
1383                         }
1384
1385                         $element = ['type' => str_replace('as:', '', JsonLD::fetchElement($tag, '@type')),
1386                                 'href' => JsonLD::fetchElement($tag, 'as:href', '@id'),
1387                                 'name' => JsonLD::fetchElement($tag, 'as:name', '@value')];
1388
1389                         if (empty($element['type'])) {
1390                                 continue;
1391                         }
1392
1393                         if (empty($element['href'])) {
1394                                 $element['href'] = $element['name'];
1395                         }
1396
1397                         $taglist[] = $element;
1398                 }
1399                 return $taglist;
1400         }
1401
1402         /**
1403          * Convert emojis from JSON-LD format into a simplified format
1404          *
1405          * @param array $emojis
1406          * @return array with emojis in a simplified format
1407          */
1408         private static function processEmojis(array $emojis): array
1409         {
1410                 $emojilist = [];
1411
1412                 foreach ($emojis as $emoji) {
1413                         if (empty($emoji) || (JsonLD::fetchElement($emoji, '@type') != 'toot:Emoji') || empty($emoji['as:icon'])) {
1414                                 continue;
1415                         }
1416
1417                         $url = JsonLD::fetchElement($emoji['as:icon'], 'as:url', '@id');
1418                         $element = ['name' => JsonLD::fetchElement($emoji, 'as:name', '@value'),
1419                                 'href' => $url];
1420
1421                         $emojilist[] = $element;
1422                 }
1423
1424                 return $emojilist;
1425         }
1426
1427         /**
1428          * Convert attachments from JSON-LD format into a simplified format
1429          *
1430          * @param array $attachments Attachments in JSON-LD format
1431          *
1432          * @return array Attachments in a simplified format
1433          */
1434         private static function processAttachments(array $attachments): array
1435         {
1436                 $attachlist = [];
1437
1438                 // Removes empty values
1439                 $attachments = array_filter($attachments);
1440
1441                 foreach ($attachments as $attachment) {
1442                         switch (JsonLD::fetchElement($attachment, '@type')) {
1443                                 case 'as:Page':
1444                                         $pageUrl = null;
1445                                         $pageImage = null;
1446
1447                                         $urls = JsonLD::fetchElementArray($attachment, 'as:url');
1448                                         foreach ($urls as $url) {
1449                                                 // Single scalar URL case
1450                                                 if (is_string($url)) {
1451                                                         $pageUrl = $url;
1452                                                         continue;
1453                                                 }
1454
1455                                                 $href = JsonLD::fetchElement($url, 'as:href', '@id');
1456                                                 $mediaType = JsonLD::fetchElement($url, 'as:mediaType', '@value');
1457                                                 if (Strings::startsWith($mediaType, 'image')) {
1458                                                         $pageImage = $href;
1459                                                 } else {
1460                                                         $pageUrl = $href;
1461                                                 }
1462                                         }
1463
1464                                         $attachlist[] = [
1465                                                 'type'  => 'link',
1466                                                 'title' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1467                                                 'desc'  => JsonLD::fetchElement($attachment, 'as:summary', '@value'),
1468                                                 'url'   => $pageUrl,
1469                                                 'image' => $pageImage,
1470                                         ];
1471                                         break;
1472                                 case 'as:Image':
1473                                         $mediaType = JsonLD::fetchElement($attachment, 'as:mediaType', '@value');
1474                                         $imageFullUrl = JsonLD::fetchElement($attachment, 'as:url', '@id');
1475                                         $imagePreviewUrl = null;
1476                                         // Multiple URLs?
1477                                         if (!$imageFullUrl && ($urls = JsonLD::fetchElementArray($attachment, 'as:url'))) {
1478                                                 $imageVariants = [];
1479                                                 $previewVariants = [];
1480                                                 foreach ($urls as $url) {
1481                                                         // Scalar URL, no discrimination possible
1482                                                         if (is_string($url)) {
1483                                                                 $imageFullUrl = $url;
1484                                                                 continue;
1485                                                         }
1486
1487                                                         // Not sure what to do with a different Link media type than the base Image, we skip
1488                                                         if ($mediaType != JsonLD::fetchElement($url, 'as:mediaType', '@value')) {
1489                                                                 continue;
1490                                                         }
1491
1492                                                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1493
1494                                                         // Default URL choice if no discriminating width is provided
1495                                                         $imageFullUrl = $href ?? $imageFullUrl;
1496
1497                                                         $width = intval(JsonLD::fetchElement($url, 'as:width', '@value') ?? 1);
1498
1499                                                         if ($href && $width) {
1500                                                                 $imageVariants[$width] = $href;
1501                                                                 // 632 is the ideal width for full screen frio posts, we compute the absolute distance to it
1502                                                                 $previewVariants[abs(632 - $width)] = $href;
1503                                                         }
1504                                                 }
1505
1506                                                 if ($imageVariants) {
1507                                                         // Taking the maximum size image
1508                                                         ksort($imageVariants);
1509                                                         $imageFullUrl = array_pop($imageVariants);
1510
1511                                                         // Taking the minimum number distance to the target distance
1512                                                         ksort($previewVariants);
1513                                                         $imagePreviewUrl = array_shift($previewVariants);
1514                                                 }
1515
1516                                                 unset($imageVariants);
1517                                                 unset($previewVariants);
1518                                         }
1519
1520                                         $attachlist[] = [
1521                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1522                                                 'mediaType' => $mediaType,
1523                                                 'name'  => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1524                                                 'url'   => $imageFullUrl,
1525                                                 'image' => $imagePreviewUrl !== $imageFullUrl ? $imagePreviewUrl : null,
1526                                         ];
1527                                         break;
1528                                 default:
1529                                         $attachlist[] = [
1530                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1531                                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType', '@value'),
1532                                                 'name' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1533                                                 'url' => JsonLD::fetchElement($attachment, 'as:url', '@id'),
1534                                                 'height' => JsonLD::fetchElement($attachment, 'as:height', '@value'),
1535                                                 'width' => JsonLD::fetchElement($attachment, 'as:width', '@value'),
1536                                                 'image' => JsonLD::fetchElement($attachment, 'as:image', '@id')
1537                                         ];
1538                         }
1539                 }
1540
1541                 return $attachlist;
1542         }
1543
1544         /**
1545          * Convert questions from JSON-LD format into a simplified format
1546          *
1547          * @param array $object
1548          *
1549          * @return array Questions in a simplified format
1550          */
1551         private static function processQuestion(array $object): array
1552         {
1553                 $question = [];
1554
1555                 if (!empty($object['as:oneOf'])) {
1556                         $question['multiple'] = false;
1557                         $options = JsonLD::fetchElementArray($object, 'as:oneOf') ?? [];
1558                 } elseif (!empty($object['as:anyOf'])) {
1559                         $question['multiple'] = true;
1560                         $options = JsonLD::fetchElementArray($object, 'as:anyOf') ?? [];
1561                 } else {
1562                         return [];
1563                 }
1564
1565                 $closed = JsonLD::fetchElement($object, 'as:closed', '@value');
1566                 if (!empty($closed)) {
1567                         $question['end-time'] = $closed;
1568                 } else {
1569                         $question['end-time'] = JsonLD::fetchElement($object, 'as:endTime', '@value');
1570                 }
1571
1572                 $question['voters']  = (int)JsonLD::fetchElement($object, 'toot:votersCount', '@value');
1573                 $question['options'] = [];
1574
1575                 $voters = 0;
1576
1577                 foreach ($options as $option) {
1578                         if (JsonLD::fetchElement($option, '@type') != 'as:Note') {
1579                                 continue;
1580                         }
1581
1582                         $name = JsonLD::fetchElement($option, 'as:name', '@value');
1583
1584                         if (empty($option['as:replies'])) {
1585                                 continue;
1586                         }
1587
1588                         $replies = JsonLD::fetchElement($option['as:replies'], 'as:totalItems', '@value');
1589
1590                         $question['options'][] = ['name' => $name, 'replies' => $replies];
1591
1592                         $voters += (int)$replies;
1593                 }
1594
1595                 // For single choice question we can count the number of voters if not provided (like with Misskey)
1596                 if (empty($question['voters']) && !$question['multiple']) {
1597                         $question['voters'] = $voters;
1598                 }
1599
1600                 return $question;
1601         }
1602
1603         /**
1604          * Fetch the original source or content with the "language" Markdown or HTML
1605          *
1606          * @param array $object
1607          * @param array $object_data
1608          *
1609          * @return array Object data (?)
1610          * @throws \Exception
1611          */
1612         private static function getSource(array $object, array $object_data): array
1613         {
1614                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/bbcode');
1615                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1616                 if (!empty($object_data['source'])) {
1617                         return $object_data;
1618                 }
1619
1620                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/markdown');
1621                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1622                 if (!empty($object_data['source'])) {
1623                         $object_data['source'] = Markdown::toBBCode($object_data['source']);
1624                         return $object_data;
1625                 }
1626
1627                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/html');
1628                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1629                 if (!empty($object_data['source'])) {
1630                         $object_data['source'] = HTML::toBBCode($object_data['source']);
1631                         return $object_data;
1632                 }
1633
1634                 return $object_data;
1635         }
1636
1637         /**
1638          * Extracts a potential alternate URL from a list of additional URL elements
1639          *
1640          * @param array $urls
1641          * @return string
1642          */
1643         private static function extractAlternateUrl(array $urls): string
1644         {
1645                 $alternateUrl = '';
1646                 foreach ($urls as $key => $url) {
1647                         // Not a list but a single URL element
1648                         if (!is_numeric($key)) {
1649                                 continue;
1650                         }
1651
1652                         if (empty($url['@type']) || ($url['@type'] != 'as:Link')) {
1653                                 continue;
1654                         }
1655
1656                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1657                         if (empty($href)) {
1658                                 continue;
1659                         }
1660
1661                         $mediatype = JsonLD::fetchElement($url, 'as:mediaType');
1662                         if (empty($mediatype)) {
1663                                 continue;
1664                         }
1665
1666                         if ($mediatype == 'text/html') {
1667                                 $alternateUrl = $href;
1668                         }
1669                 }
1670
1671                 return $alternateUrl;
1672         }
1673
1674         /**
1675          * Check if the "as:url" element is an array with multiple links
1676          * This is the case with audio and video posts.
1677          * Then the links are added as attachments
1678          *
1679          * @param array $urls The object URL list
1680          * @return array an array of attachments
1681          */
1682         private static function processAttachmentUrls(array $urls): array
1683         {
1684                 $attachments = [];
1685                 foreach ($urls as $key => $url) {
1686                         // Not a list but a single URL element
1687                         if (!is_numeric($key)) {
1688                                 continue;
1689                         }
1690
1691                         if (empty($url['@type']) || ($url['@type'] != 'as:Link')) {
1692                                 continue;
1693                         }
1694
1695                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1696                         if (empty($href)) {
1697                                 continue;
1698                         }
1699
1700                         $mediatype = JsonLD::fetchElement($url, 'as:mediaType');
1701                         if (empty($mediatype)) {
1702                                 continue;
1703                         }
1704
1705                         $filetype = strtolower(substr($mediatype, 0, strpos($mediatype, '/')));
1706
1707                         if ($filetype == 'audio') {
1708                                 $attachments[] = ['type' => $filetype, 'mediaType' => $mediatype, 'url' => $href, 'height' => null, 'size' => null, 'name' => ''];
1709                         } elseif ($filetype == 'video') {
1710                                 $height = (int)JsonLD::fetchElement($url, 'as:height', '@value');
1711                                 // PeerTube audio-only track
1712                                 if ($height === 0) {
1713                                         continue;
1714                                 }
1715
1716                                 $size = (int)JsonLD::fetchElement($url, 'pt:size', '@value');
1717                                 $attachments[] = ['type' => $filetype, 'mediaType' => $mediatype, 'url' => $href, 'height' => $height, 'size' => $size, 'name' => ''];
1718                         } elseif (in_array($mediatype, ['application/x-bittorrent', 'application/x-bittorrent;x-scheme-handler/magnet'])) {
1719                                 $height = (int)JsonLD::fetchElement($url, 'as:height', '@value');
1720
1721                                 // For Torrent links we always store the highest resolution
1722                                 if (!empty($attachments[$mediatype]['height']) && ($height < $attachments[$mediatype]['height'])) {
1723                                         continue;
1724                                 }
1725
1726                                 $attachments[$mediatype] = ['type' => $mediatype, 'mediaType' => $mediatype, 'url' => $href, 'height' => $height, 'size' => null, 'name' => ''];
1727                         } elseif ($mediatype == 'application/x-mpegURL') {
1728                                 // PeerTube exception, actual video link is in the tags of this URL element
1729                                 $attachments = array_merge($attachments, self::processAttachmentUrls($url['as:tag']));
1730                         }
1731                 }
1732
1733                 return array_values($attachments);
1734         }
1735
1736         /**
1737          * Fetches data from the object part of an activity
1738          *
1739          * @param array $object
1740          *
1741          * @return array|bool Object data or FALSE if $object does not contain @id element
1742          * @throws \Exception
1743          */
1744         private static function processObject(array $object)
1745         {
1746                 if (!JsonLD::fetchElement($object, '@id')) {
1747                         return false;
1748                 }
1749
1750                 $object_data = [];
1751                 $object_data['object_type'] = JsonLD::fetchElement($object, '@type');
1752                 $object_data['id'] = JsonLD::fetchElement($object, '@id');
1753                 $object_data['reply-to-id'] = JsonLD::fetchElement($object, 'as:inReplyTo', '@id');
1754
1755                 // An empty "id" field is translated to "./" by the compactor, so we have to check for this content
1756                 if (empty($object_data['reply-to-id']) || ($object_data['reply-to-id'] == './')) {
1757                         $object_data['reply-to-id'] = $object_data['id'];
1758
1759                         // On activities the "reply to" is the id of the object it refers to
1760                         if (in_array($object_data['object_type'], self::ACTIVITY_TYPES)) {
1761                                 $object_id = JsonLD::fetchElement($object, 'as:object', '@id');
1762                                 if (!empty($object_id)) {
1763                                         $object_data['reply-to-id'] = $object_id;
1764                                 }
1765                         }
1766                 } else {
1767                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
1768                         $replyToId = Item::getURIByLink($object_data['reply-to-id']);
1769                         if (!empty($replyToId) && ($object_data['reply-to-id'] != $replyToId)) {
1770                                 Logger::notice('Fix wrong reply-to', ['received' => $object_data['reply-to-id'], 'correct' => $replyToId]);
1771                                 $object_data['reply-to-id'] = $replyToId;
1772                         }
1773                 }
1774
1775                 $object_data['published'] = JsonLD::fetchElement($object, 'as:published', '@value');
1776                 $object_data['updated'] = JsonLD::fetchElement($object, 'as:updated', '@value');
1777
1778                 if (empty($object_data['updated'])) {
1779                         $object_data['updated'] = $object_data['published'];
1780                 }
1781
1782                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
1783                         $object_data['published'] = $object_data['updated'];
1784                 }
1785
1786                 $actor = JsonLD::fetchElement($object, 'as:attributedTo', '@id');
1787                 if (empty($actor)) {
1788                         $actor = JsonLD::fetchElement($object, 'as:actor', '@id');
1789                 }
1790
1791                 $location = JsonLD::fetchElement($object, 'as:location', 'as:name', '@type', 'as:Place');
1792                 $location = JsonLD::fetchElement($location, 'location', '@value');
1793                 if ($location) {
1794                         // Some AP software allow formatted text in post location, so we run all the text converters we have to boil
1795                         // down to HTML and then finally format to plaintext.
1796                         $location = Markdown::convert($location);
1797                         $location = BBCode::toPlaintext($location);
1798                 }
1799
1800                 $object_data['sc:identifier'] = JsonLD::fetchElement($object, 'sc:identifier', '@value');
1801                 $object_data['diaspora:guid'] = JsonLD::fetchElement($object, 'diaspora:guid', '@value');
1802                 $object_data['diaspora:comment'] = JsonLD::fetchElement($object, 'diaspora:comment', '@value');
1803                 $object_data['diaspora:like'] = JsonLD::fetchElement($object, 'diaspora:like', '@value');
1804                 $object_data['actor'] = $object_data['author'] = $actor;
1805                 $object_data['context'] = JsonLD::fetchElement($object, 'as:context', '@id');
1806                 $object_data['conversation'] = JsonLD::fetchElement($object, 'ostatus:conversation', '@id');
1807                 $object_data['sensitive'] = JsonLD::fetchElement($object, 'as:sensitive');
1808                 $object_data['name'] = JsonLD::fetchElement($object, 'as:name', '@value');
1809                 $object_data['summary'] = JsonLD::fetchElement($object, 'as:summary', '@value');
1810                 $object_data['content'] = JsonLD::fetchElement($object, 'as:content', '@value');
1811                 $object_data['mediatype'] = JsonLD::fetchElement($object, 'as:mediaType', '@value');
1812                 $object_data = self::getSource($object, $object_data);
1813                 $object_data['start-time'] = JsonLD::fetchElement($object, 'as:startTime', '@value');
1814                 $object_data['end-time'] = JsonLD::fetchElement($object, 'as:endTime', '@value');
1815                 $object_data['location'] = $location;
1816                 $object_data['latitude'] = JsonLD::fetchElement($object, 'as:location', 'as:latitude', '@type', 'as:Place');
1817                 $object_data['latitude'] = JsonLD::fetchElement($object_data, 'latitude', '@value');
1818                 $object_data['longitude'] = JsonLD::fetchElement($object, 'as:location', 'as:longitude', '@type', 'as:Place');
1819                 $object_data['longitude'] = JsonLD::fetchElement($object_data, 'longitude', '@value');
1820                 $object_data['attachments'] = self::processAttachments(JsonLD::fetchElementArray($object, 'as:attachment') ?? []);
1821                 $object_data['tags'] = self::processTags(JsonLD::fetchElementArray($object, 'as:tag') ?? []);
1822                 $object_data['emojis'] = self::processEmojis(JsonLD::fetchElementArray($object, 'as:tag', null, '@type', 'toot:Emoji') ?? []);
1823                 $object_data['languages'] = self::processLanguages(JsonLD::fetchElementArray($object, 'sc:inLanguage') ?? []);
1824                 $object_data['generator'] = JsonLD::fetchElement($object, 'as:generator', 'as:name', '@type', 'as:Application');
1825                 $object_data['generator'] = JsonLD::fetchElement($object_data, 'generator', '@value');
1826                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'as:url', '@id');
1827
1828                 // Special treatment for Hubzilla links
1829                 if (is_array($object_data['alternate-url'])) {
1830                         $object_data['alternate-url'] = JsonLD::fetchElement($object_data['alternate-url'], 'as:href', '@id');
1831
1832                         if (!is_string($object_data['alternate-url'])) {
1833                                 $object_data['alternate-url'] = JsonLD::fetchElement($object['as:url'], 'as:href', '@id');
1834                         }
1835                 }
1836
1837                 if (!empty($object_data['alternate-url']) && !Network::isValidHttpUrl($object_data['alternate-url'])) {
1838                         $object_data['alternate-url'] = null;
1839                 }
1840
1841                 if (in_array($object_data['object_type'], ['as:Audio', 'as:Video'])) {
1842                         $object_data['alternate-url'] = self::extractAlternateUrl($object['as:url'] ?? []) ?: $object_data['alternate-url'];
1843                         $object_data['attachments'] = array_merge($object_data['attachments'], self::processAttachmentUrls($object['as:url'] ?? []));
1844                 }
1845
1846                 // For page types we expect that the alternate url posts to some page.
1847                 // So we add this to the attachments if it differs from the id.
1848                 // Currently only Lemmy is using the page type.
1849                 if (($object_data['object_type'] == 'as:Page') && !empty($object_data['alternate-url']) && !Strings::compareLink($object_data['alternate-url'], $object_data['id'])) {
1850                         $object_data['attachments'][] = ['url' => $object_data['alternate-url']];
1851                         $object_data['alternate-url'] = null;
1852                 }
1853
1854                 if ($object_data['object_type'] == 'as:Question') {
1855                         $object_data['question'] = self::processQuestion($object);
1856                 }
1857
1858                 $receiverdata = self::getReceivers($object, $object_data['actor'] ?? '', $object_data['tags'], true);
1859                 $receivers = $reception_types = [];
1860                 foreach ($receiverdata as $key => $data) {
1861                         $receivers[$key] = $data['uid'];
1862                         $reception_types[$data['uid']] = $data['type'] ?? 0;
1863                 }
1864
1865                 $object_data['receiver_urls']  = self::getReceiverURL($object);
1866                 $object_data['receiver']       = $receivers;
1867                 $object_data['reception_type'] = $reception_types;
1868
1869                 $object_data['unlisted'] = in_array(-1, $object_data['receiver']);
1870                 unset($object_data['receiver'][-1]);
1871                 unset($object_data['reception_type'][-1]);
1872
1873                 return $object_data;
1874         }
1875 }