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