src/Protocol/ActivityPub/Receiver.php

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