src/Protocol/ActivityPub/Receiver.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2010-2022, the Friendica project
   4  *
   5  * @license GNU AGPL version 3 or any later version
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU Affero General Public License as
   9  * published by the Free Software Foundation, either version 3 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU Affero General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Affero General Public License
  18  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  19  *
  20  */
  21
  22 namespace Friendica\Protocol\ActivityPub;
  23
  24 use Friendica\Content\Text\BBCode;
  25 use Friendica\Database\DBA;
  26 use Friendica\Content\Text\HTML;
  27 use Friendica\Content\Text\Markdown;
  28 use Friendica\Core\Logger;
  29 use Friendica\Core\Protocol;
  30 use Friendica\Core\System;
  31 use Friendica\Core\Worker;
  32 use Friendica\Database\Database;
  33 use Friendica\DI;
  34 use Friendica\Model\Contact;
  35 use Friendica\Model\APContact;
  36 use Friendica\Model\Item;
  37 use Friendica\Model\Post;
  38 use Friendica\Model\User;
  39 use Friendica\Protocol\Activity;
  40 use Friendica\Protocol\ActivityPub;
  41 use Friendica\Util\DateTimeFormat;
  42 use Friendica\Util\HTTPSignature;
  43 use Friendica\Util\JsonLD;
  44 use Friendica\Util\LDSignature;
  45 use Friendica\Util\Network;
  46 use Friendica\Util\Strings;
  47
  48 /**
  49  * ActivityPub Receiver Protocol class
  50  *
  51  * To-Do:
  52  * @todo Undo Announce
  53  *
  54  * Check what this is meant to do:
  55  * - Add
  56  * - Block
  57  * - Flag
  58  * - Remove
  59  * - Undo Block
  60  */
  61 class Receiver
  62 {
  63         const PUBLIC_COLLECTION = 'as:Public';
  64         const ACCOUNT_TYPES = ['as:Person', 'as:Organization', 'as:Service', 'as:Group', 'as:Application'];
  65         const CONTENT_TYPES = ['as:Note', 'as:Article', 'as:Video', 'as:Image', 'as:Event', 'as:Audio', 'as:Page', 'as:Question'];
  66         const ACTIVITY_TYPES = ['as:Like', 'as:Dislike', 'as:Accept', 'as:Reject', 'as:TentativeAccept'];
  67
  68         const TARGET_UNKNOWN = 0;
  69         const TARGET_TO = 1;
  70         const TARGET_CC = 2;
  71         const TARGET_BTO = 3;
  72         const TARGET_BCC = 4;
  73         const TARGET_FOLLOWER = 5;
  74         const TARGET_ANSWER = 6;
  75         const TARGET_GLOBAL = 7;
  76
  77         const COMPLETION_NONE    = 0;
  78         const COMPLETION_ANNOUCE = 1;
  79         const COMPLETION_RELAY   = 2;
  80         const COMPLETION_MANUAL  = 3;
  81         const COMPLETION_AUTO    = 4;
  82
  83         /**
  84          * Checks incoming message from the inbox
  85          *
  86          * @param string  $body Body string
  87          * @param array   $header Header lines
  88          * @param integer $uid User ID
  89          * @return void
  90          * @throws \Exception
  91          */
  92         public static function processInbox(string $body, array $header, int $uid)
  93         {
  94                 $activity = json_decode($body, true);
  95                 if (empty($activity)) {
  96                         Logger::warning('Invalid body.');
  97                         return;
  98                 }
  99
 100                 $ldactivity = JsonLD::compact($activity);
 101
 102                 $actor = JsonLD::fetchElement($ldactivity, 'as:actor', '@id') ?? '';
 103
 104                 $apcontact = APContact::getByURL($actor);
 105
 106                 if (empty($apcontact)) {
 107                         Logger::notice('Unable to retrieve AP contact for actor - message is discarded', ['actor' => $actor]);
 108                         return;
 109                 } elseif (APContact::isRelay($apcontact)) {
 110                         self::processRelayPost($ldactivity, $actor);
 111                         return;
 112                 } else {
 113                         APContact::unmarkForArchival($apcontact);
 114                 }
 115
 116                 $sig_contact = HTTPSignature::getKeyIdContact($header);
 117                 if (APContact::isRelay($sig_contact)) {
 118                         Logger::info('Message from a relay', ['url' => $sig_contact['url']]);
 119                         self::processRelayPost($ldactivity, $sig_contact['url']);
 120                         return;
 121                 }
 122
 123                 $http_signer = HTTPSignature::getSigner($body, $header);
 124                 if ($http_signer === false) {
 125                         Logger::notice('Invalid HTTP signature, message will not be trusted.', ['uid' => $uid, 'actor' => $actor, 'header' => $header, 'body' => $body]);
 126                         $signer = [];
 127                 } elseif (empty($http_signer)) {
 128                         Logger::info('Signer is a tombstone. The message will be discarded, the signer account is deleted.');
 129                         return;
 130                 } else {
 131                         Logger::info('Valid HTTP signature', ['signer' => $http_signer]);
 132                         $signer = [$http_signer];
 133                 }
 134
 135                 Logger::info('Message for user ' . $uid . ' is from actor ' . $actor);
 136
 137                 if ($http_signer === false) {
 138                         $trust_source = false;
 139                 } elseif (LDSignature::isSigned($activity)) {
 140                         $ld_signer = LDSignature::getSigner($activity);
 141                         if (empty($ld_signer)) {
 142                                 Logger::info('Invalid JSON-LD signature from ' . $actor);
 143                         } elseif ($ld_signer != $http_signer) {
 144                                 $signer[] = $ld_signer;
 145                         }
 146                         if (!empty($ld_signer && ($actor == $http_signer))) {
 147                                 Logger::info('The HTTP and the JSON-LD signature belong to ' . $ld_signer);
 148                                 $trust_source = true;
 149                         } elseif (!empty($ld_signer)) {
 150                                 Logger::info('JSON-LD signature is signed by ' . $ld_signer);
 151                                 $trust_source = true;
 152                         } elseif ($actor == $http_signer) {
 153                                 Logger::info('Bad JSON-LD signature, but HTTP signer fits the actor.');
 154                                 $trust_source = true;
 155                         } else {
 156                                 Logger::info('Invalid JSON-LD signature and the HTTP signer is different.');
 157                                 $trust_source = false;
 158                         }
 159                 } elseif ($actor == $http_signer) {
 160                         Logger::info('Trusting post without JSON-LD signature, The actor fits the HTTP signer.');
 161                         $trust_source = true;
 162                 } else {
 163                         Logger::info('No JSON-LD signature, different actor.');
 164                         $trust_source = false;
 165                 }
 166
 167                 self::processActivity($ldactivity, $body, $uid, $trust_source, true, $signer, $http_signer);
 168         }
 169
 170         /**
 171          * Process incoming posts from relays
 172          *
 173          * @param array  $activity
 174          * @param string $actor
 175          * @return void
 176          */
 177         private static function processRelayPost(array $activity, string $actor)
 178         {
 179                 $type = JsonLD::fetchElement($activity, '@type');
 180                 if (!$type) {
 181                         Logger::notice('Empty type', ['activity' => $activity, 'actor' => $actor]);
 182                         return;
 183                 }
 184
 185                 $object_type = JsonLD::fetchElement($activity, 'as:object', '@type') ?? '';
 186
 187                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 188                 if (empty($object_id)) {
 189                         Logger::notice('No object id found', ['type' => $type, 'object_type' => $object_type, 'actor' => $actor, 'activity' => $activity]);
 190                         return;
 191                 }
 192
 193                 $handle = ($type == 'as:Announce');
 194
 195                 if (!$handle && in_array($type, ['as:Create', 'as:Update'])) {
 196                         $handle = in_array($object_type, self::CONTENT_TYPES);
 197                 }
 198
 199                 if (!$handle) {
 200                         $trust_source = false;
 201                         $object_data = self::prepareObjectData($activity, 0, false, $trust_source);
 202
 203                         if (!$trust_source) {
 204                                 Logger::notice('Activity trust could not be achieved.',  ['type' => $type, 'object_type' => $object_type, 'object_id' => $object_id, 'actor' => $actor, 'activity' => $activity]);
 205                                 return;
 206                         }
 207
 208                         if (empty($object_data)) {
 209                                 Logger::notice('No object data found', ['type' => $type, 'object_type' => $object_type, 'object_id' => $object_id, 'actor' => $actor, 'activity' => $activity]);
 210                                 return;
 211                         }
 212
 213                         if (self::routeActivities($object_data, $type, true)) {
 214                                 Logger::debug('Handled activity', ['type' => $type, 'object_type' => $object_type, 'object_id' => $object_id, 'actor' => $actor]);
 215                         } else {
 216                                 Logger::info('Unhandled activity', ['type' => $type, 'object_type' => $object_type, 'object_id' => $object_id, 'actor' => $actor, 'activity' => $activity]);
 217                         }
 218                         return;
 219                 }
 220
 221                 $contact = Contact::getByURL($actor);
 222                 if (empty($contact)) {
 223                         Logger::info('Relay contact not found', ['actor' => $actor]);
 224                         return;
 225                 }
 226
 227                 if (!in_array($contact['rel'], [Contact::SHARING, Contact::FRIEND])) {
 228                         Logger::notice('Relay is no sharer', ['actor' => $actor]);
 229                         return;
 230                 }
 231
 232                 Logger::debug('Got relayed message id', ['id' => $object_id, 'actor' => $actor]);
 233
 234                 $item_id = Item::searchByLink($object_id);
 235                 if ($item_id) {
 236                         Logger::info('Relayed message already exists', ['id' => $object_id, 'item' => $item_id, 'actor' => $actor]);
 237                         return;
 238                 }
 239
 240                 $id = Processor::fetchMissingActivity($object_id, [], $actor, self::COMPLETION_RELAY);
 241                 if (empty($id)) {
 242                         Logger::notice('Relayed message had not been fetched', ['id' => $object_id, 'actor' => $actor]);
 243                         return;
 244                 }
 245         }
 246
 247         /**
 248          * Fetches the object type for a given object id
 249          *
 250          * @param array   $activity
 251          * @param string  $object_id Object ID of the the provided object
 252          * @param integer $uid       User ID
 253          *
 254          * @return string with object type or NULL
 255          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 256          * @throws \ImagickException
 257          */
 258         private static function fetchObjectType(array $activity, string $object_id, int $uid = 0)
 259         {
 260                 if (!empty($activity['as:object'])) {
 261                         $object_type = JsonLD::fetchElement($activity['as:object'], '@type');
 262                         if (!empty($object_type)) {
 263                                 return $object_type;
 264                         }
 265                 }
 266
 267                 if (Post::exists(['uri' => $object_id, 'gravity' => [GRAVITY_PARENT, GRAVITY_COMMENT]])) {
 268                         // We just assume "note" since it doesn't make a difference for the further processing
 269                         return 'as:Note';
 270                 }
 271
 272                 $profile = APContact::getByURL($object_id);
 273                 if (!empty($profile['type'])) {
 274                         APContact::unmarkForArchival($profile);
 275                         return 'as:' . $profile['type'];
 276                 }
 277
 278                 $data = Processor::fetchCachedActivity($object_id, $uid);
 279                 if (!empty($data)) {
 280                         $object = JsonLD::compact($data);
 281                         $type = JsonLD::fetchElement($object, '@type');
 282                         if (!empty($type)) {
 283                                 return $type;
 284                         }
 285                 }
 286
 287                 return null;
 288         }
 289
 290         /**
 291          * Prepare the object array
 292          *
 293          * @param array   $activity     Array with activity data
 294          * @param integer $uid          User ID
 295          * @param boolean $push         Message had been pushed to our system
 296          * @param boolean $trust_source Do we trust the source?
 297          *
 298          * @return array with object data
 299          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 300          * @throws \ImagickException
 301          */
 302         public static function prepareObjectData(array $activity, int $uid, bool $push, bool &$trust_source): array
 303         {
 304                 $id        = JsonLD::fetchElement($activity, '@id');
 305                 $type      = JsonLD::fetchElement($activity, '@type');
 306                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 307
 308                 if (!empty($object_id) && in_array($type, ['as:Create', 'as:Update'])) {
 309                         $fetch_id = $object_id;
 310                 } else {
 311                         $fetch_id = $id;
 312                 }
 313
 314                 if (!empty($activity['as:object'])) {
 315                         $object_type = JsonLD::fetchElement($activity['as:object'], '@type');
 316                 }
 317
 318                 if (!empty($id) && !$trust_source) {
 319                         $fetch_uid = $uid ?: self::getBestUserForActivity($activity);
 320
 321                         $fetched_activity = Processor::fetchCachedActivity($fetch_id, $fetch_uid);
 322                         if (!empty($fetched_activity)) {
 323                                 $object = JsonLD::compact($fetched_activity);
 324
 325                                 $fetched_id   = JsonLD::fetchElement($object, '@id');
 326                                 $fetched_type = JsonLD::fetchElement($object, '@type');
 327
 328                                 if (($fetched_id == $id) && !empty($fetched_type) && ($fetched_type == $type)) {
 329                                         Logger::info('Activity had been fetched successfully', ['id' => $id]);
 330                                         $trust_source = true;
 331                                         $activity = $object;
 332                                 } elseif (($fetched_id == $object_id) && !empty($fetched_type) && ($fetched_type == $object_type)) {
 333                                         Logger::info('Fetched data is the object instead of the activity', ['id' => $id]);
 334                                         $trust_source = true;
 335                                         unset($object['@context']);
 336                                         $activity['as:object'] = $object;
 337                                 } else {
 338                                         Logger::info('Activity id is not equal', ['id' => $id, 'fetched' => $fetched_id]);
 339                                 }
 340                         } else {
 341                                 Logger::info('Activity could not been fetched', ['id' => $id]);
 342                         }
 343                 }
 344
 345                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 346                 if (empty($actor)) {
 347                         Logger::info('Empty actor', ['activity' => $activity]);
 348                         return [];
 349                 }
 350
 351                 $type = JsonLD::fetchElement($activity, '@type');
 352
 353                 // Fetch all receivers from to, cc, bto and bcc
 354                 $receiverdata = self::getReceivers($activity, $actor);
 355                 $receivers = $reception_types = [];
 356                 foreach ($receiverdata as $key => $data) {
 357                         $receivers[$key] = $data['uid'];
 358                         $reception_types[$data['uid']] = $data['type'] ?? self::TARGET_UNKNOWN;
 359                 }
 360
 361                 $urls = self::getReceiverURL($activity);
 362
 363                 // When it is a delivery to a personal inbox we add that user to the receivers
 364                 if (!empty($uid)) {
 365                         $additional = [$uid => $uid];
 366                         $receivers = array_replace($receivers, $additional);
 367                         if (empty($activity['thread-completion']) && (empty($reception_types[$uid]) || in_array($reception_types[$uid], [self::TARGET_UNKNOWN, self::TARGET_FOLLOWER, self::TARGET_ANSWER, self::TARGET_GLOBAL]))) {
 368                                 $reception_types[$uid] = self::TARGET_BCC;
 369                                 $owner = User::getOwnerDataById($uid);
 370                                 if (!empty($owner['url'])) {
 371                                         $urls['as:bcc'][] = $owner['url'];
 372                                 }
 373                         }
 374                 }
 375
 376                 // We possibly need some user to fetch private content,
 377                 // so we fetch one out of the receivers if no uid is provided.
 378                 $fetch_uid = $uid ?: self::getBestUserForActivity($activity);
 379
 380                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 381                 if (empty($object_id)) {
 382                         Logger::info('No object found');
 383                         return [];
 384                 }
 385
 386                 if (!is_string($object_id)) {
 387                         Logger::info('Invalid object id', ['object' => $object_id]);
 388                         return [];
 389                 }
 390
 391                 $object_type = self::fetchObjectType($activity, $object_id, $fetch_uid);
 392
 393                 // Fetch the activity on Lemmy "Announce" messages (announces of activities)
 394                 if (($type == 'as:Announce') && in_array($object_type, array_merge(self::ACTIVITY_TYPES, ['as:Delete', 'as:Undo', 'as:Update']))) {
 395                         Logger::debug('Fetch announced activity', ['object' => $object_id]);
 396                         $data = Processor::fetchCachedActivity($object_id, $fetch_uid);
 397                         if (!empty($data)) {
 398                                 $type = $object_type;
 399                                 $activity = JsonLD::compact($data);
 400
 401                                 // Some variables need to be refetched since the activity changed
 402                                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 403                                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 404                                 $object_type = self::fetchObjectType($activity, $object_id, $fetch_uid);
 405                         }
 406                 }
 407
 408                 // Any activities on account types must not be altered
 409                 if (in_array($object_type, self::ACCOUNT_TYPES)) {
 410                         $object_data = [];
 411                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 412                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 413                         $object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor', '@id');
 414                         $object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
 415                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 416                         $object_data['push'] = $push;
 417                         if (!$trust_source && ($type == 'as:Delete')) {
 418                                 $apcontact = APContact::getByURL($object_data['object_id'], true);
 419                                 $trust_source = empty($apcontact) || ($apcontact['type'] == 'Tombstone') || $apcontact['suspended'];
 420                         }
 421                 } elseif (in_array($type, ['as:Create', 'as:Update', 'as:Announce', 'as:Invite']) || strpos($type, '#emojiReaction')) {
 422                         // Fetch the content only on activities where this matters
 423                         // We can receive "#emojiReaction" when fetching content from Hubzilla systems
 424                         // Always fetch on "Announce"
 425                         $object_data = self::fetchObject($object_id, $activity['as:object'], $trust_source && ($type != 'as:Announce'), $fetch_uid);
 426                         if (empty($object_data)) {
 427                                 Logger::info("Object data couldn't be processed");
 428                                 return [];
 429                         }
 430
 431                         $object_data['object_id'] = $object_id;
 432
 433                         if ($type == 'as:Announce') {
 434                                 $object_data['push'] = false;
 435                         } else {
 436                                 $object_data['push'] = $push;
 437                         }
 438
 439                         // Test if it is an answer to a mail
 440                         if (DBA::exists('mail', ['uri' => $object_data['reply-to-id']])) {
 441                                 $object_data['directmessage'] = true;
 442                         } else {
 443                                 $object_data['directmessage'] = JsonLD::fetchElement($activity, 'litepub:directMessage');
 444                         }
 445                 } elseif (in_array($type, array_merge(self::ACTIVITY_TYPES, ['as:Follow', 'litepub:EmojiReact', 'as:View'])) && in_array($object_type, self::CONTENT_TYPES)) {
 446                         // Create a mostly empty array out of the activity data (instead of the object).
 447                         // This way we later don't have to check for the existence of each individual array element.
 448                         $object_data = self::processObject($activity);
 449                         $object_data['name'] = $type;
 450                         $object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 451                         $object_data['object_id'] = $object_id;
 452                         $object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
 453                         $object_data['push'] = $push;
 454                 } elseif (in_array($type, ['as:Add', 'as:Remove'])) {
 455                         $object_data = [];
 456                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 457                         $object_data['target_id'] = JsonLD::fetchElement($activity, 'as:target', '@id');
 458                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 459                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 460                         $object_data['object_content'] = JsonLD::fetchElement($activity['as:object'], 'as:content', '@type');
 461                         $object_data['push'] = $push;
 462                 } else {
 463                         $object_data = [];
 464                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 465                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 466                         $object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor', '@id');
 467                         $object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
 468                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 469                         $object_data['push'] = $push;
 470
 471                         // An Undo is done on the object of an object, so we need that type as well
 472                         if (($type == 'as:Undo') && !empty($object_data['object_object'])) {
 473                                 $object_data['object_object_type'] = self::fetchObjectType([], $object_data['object_object'], $fetch_uid);
 474                         }
 475
 476                         if (!$trust_source && ($type == 'as:Delete') && in_array($object_data['object_type'], array_merge(['as:Tombstone', ''], self::CONTENT_TYPES))) {
 477                                 $trust_source = Processor::isActivityGone($object_data['object_id']);
 478                                 if (!$trust_source) {
 479                                         $trust_source = !empty(APContact::getByURL($object_data['object_id'], false));
 480                                 }
 481                         }
 482                 }
 483
 484                 $object_data = self::addActivityFields($object_data, $activity);
 485
 486                 if (empty($object_data['object_type'])) {
 487                         $object_data['object_type'] = $object_type;
 488                 }
 489
 490                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
 491                         if ((empty($object_data['receiver_urls'][$element]) || in_array($element, ['as:bto', 'as:bcc'])) && !empty($urls[$element])) {
 492                                 $object_data['receiver_urls'][$element] = array_unique(array_merge($object_data['receiver_urls'][$element] ?? [], $urls[$element]));
 493                         }
 494                 }
 495
 496                 $object_data['type'] = $type;
 497                 $object_data['actor'] = $actor;
 498                 $object_data['item_receiver'] = $receivers;
 499                 $object_data['receiver'] = array_replace($object_data['receiver'] ?? [], $receivers);
 500                 $object_data['reception_type'] = array_replace($object_data['reception_type'] ?? [], $reception_types);
 501
 502 //              This check here interferes with Hubzilla posts where the author host differs from the host the post was created
 503 //              $author = $object_data['author'] ?? $actor;
 504 //              if (!empty($author) && !empty($object_data['id'])) {
 505 //                      $author_host = parse_url($author, PHP_URL_HOST);
 506 //                      $id_host = parse_url($object_data['id'], PHP_URL_HOST);
 507 //                      if ($author_host == $id_host) {
 508 //                              Logger::info('Valid hosts', ['type' => $type, 'host' => $id_host]);
 509 //                      } else {
 510 //                              Logger::notice('Differing hosts on author and id', ['type' => $type, 'author' => $author_host, 'id' => $id_host]);
 511 //                              $trust_source = false;
 512 //                      }
 513 //              }
 514
 515                 Logger::info('Processing ' . $object_data['type'] . ' ' . $object_data['object_type'] . ' ' . $object_data['id']);
 516
 517                 return $object_data;
 518         }
 519
 520         /**
 521          * Fetches the first user id from the receiver array
 522          *
 523          * @param array $receivers Array with receivers
 524          * @return integer user id;
 525          */
 526         public static function getFirstUserFromReceivers(array $receivers): int
 527         {
 528                 foreach ($receivers as $receiver) {
 529                         if (!empty($receiver)) {
 530                                 return $receiver;
 531                         }
 532                 }
 533                 return 0;
 534         }
 535
 536         /**
 537          * Processes the activity object
 538          *
 539          * @param array      $activity     Array with activity data
 540          * @param string     $body         The unprocessed body
 541          * @param int|null   $uid          User ID
 542          * @param boolean    $trust_source Do we trust the source?
 543          * @param boolean    $push         Message had been pushed to our system
 544          * @param array      $signer       The signer of the post
 545          *
 546          * @return bool
 547          *
 548          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 549          * @throws \ImagickException
 550          */
 551         public static function processActivity(array $activity, string $body = '', int $uid = null, bool $trust_source = false, bool $push = false, array $signer = [], string $http_signer = '', int $completion = Receiver::COMPLETION_AUTO): bool
 552         {
 553                 $type = JsonLD::fetchElement($activity, '@type');
 554                 if (!$type) {
 555                         Logger::info('Empty type', ['activity' => $activity]);
 556                         return true;
 557                 }
 558
 559                 if (!JsonLD::fetchElement($activity, 'as:object', '@id')) {
 560                         Logger::info('Empty object', ['activity' => $activity]);
 561                         return true;
 562                 }
 563
 564                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 565                 if (empty($actor)) {
 566                         Logger::info('Empty actor', ['activity' => $activity]);
 567                         return true;
 568                 }
 569
 570                 if (is_array($activity['as:object'])) {
 571                         $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
 572                 } else {
 573                         $attributed_to = '';
 574                 }
 575
 576                 // Test the provided signatures against the actor and "attributedTo"
 577                 if ($trust_source) {
 578                         if (!empty($attributed_to) && !empty($actor)) {
 579                                 $trust_source = (in_array($actor, $signer) && in_array($attributed_to, $signer));
 580                         } else {
 581                                 $trust_source = in_array($actor, $signer);
 582                         }
 583                 }
 584
 585                 // $trust_source is called by reference and is set to true if the content was retrieved successfully
 586                 $object_data = self::prepareObjectData($activity, $uid, $push, $trust_source);
 587                 if (empty($object_data)) {
 588                         Logger::info('No object data found', ['activity' => $activity]);
 589                         return true;
 590                 }
 591
 592                 // Lemmy is announcing activities.
 593                 // We are changing the announces into regular activities.
 594                 if (($type == 'as:Announce') && in_array($object_data['type'] ?? '', array_merge(self::ACTIVITY_TYPES, ['as:Delete', 'as:Undo', 'as:Update']))) {
 595                         Logger::debug('Change type of announce to activity', ['type' => $object_data['type']]);
 596                         $type = $object_data['type'];
 597                 }
 598
 599                 if (!empty($body) && empty($object_data['raw'])) {
 600                         $object_data['raw'] = $body;
 601                 }
 602
 603                 // Internal flag for thread completion. See Processor.php
 604                 if (!empty($activity['thread-completion'])) {
 605                         $object_data['thread-completion'] = $activity['thread-completion'];
 606                 }
 607
 608                 if (!empty($activity['completion-mode'])) {
 609                         $object_data['completion-mode'] = $activity['completion-mode'];
 610                 }
 611
 612                 if (!empty($activity['thread-children-type'])) {
 613                         $object_data['thread-children-type'] = $activity['thread-children-type'];
 614                 }
 615
 616                 // Internal flag for posts that arrived via relay
 617                 if (!empty($activity['from-relay'])) {
 618                         $object_data['from-relay'] = $activity['from-relay'];
 619                 }
 620
 621                 if ($type == 'as:Announce') {
 622                         $object_data['object_activity'] = $activity;
 623                 }
 624
 625                 if (($type == 'as:Create') && $trust_source) {
 626                         if (self::hasArrived($object_data['object_id'])) {
 627                                 Logger::info('The activity already arrived.', ['id' => $object_data['object_id']]);
 628                                 return true;
 629                         }
 630                         self::addArrivedId($object_data['object_id']);
 631
 632                         if (Queue::exists($object_data['object_id'], $type)) {
 633                                 Logger::info('The activity is already added.', ['id' => $object_data['object_id']]);
 634                                 return true;
 635                         }
 636                 }
 637
 638                 if (DI::config()->get('system', 'decoupled_receiver') && ($trust_source || DI::config()->get('debug', 'ap_inbox_store_untrusted'))) {
 639                         $object_data = Queue::add($object_data, $type, $uid, $http_signer, $push, $trust_source);
 640                 }
 641
 642                 if (!$trust_source) {
 643                         Logger::info('Activity trust could not be achieved.',  ['id' => $object_data['object_id'], 'type' => $type, 'signer' => $signer, 'actor' => $actor, 'attributedTo' => $attributed_to]);
 644                         return true;
 645                 }
 646
 647                 if (!empty($object_data['entry-id']) && DI::config()->get('system', 'decoupled_receiver') && ($push || ($completion == self::COMPLETION_RELAY))) {
 648                         if (Queue::isProcessable($object_data['entry-id'])) {
 649                                 // We delay by 5 seconds to allow to accumulate all receivers
 650                                 $delayed = date(DateTimeFormat::MYSQL, time() + 5);
 651                                 Logger::debug('Initiate processing', ['id' => $object_data['entry-id'], 'uri' => $object_data['object_id']]);
 652                                 $wid = Worker::add(['priority' => PRIORITY_HIGH, 'delayed' => $delayed], 'ProcessQueue', $object_data['entry-id']);
 653                                 Queue::setWorkerId($object_data['entry-id'], $wid);
 654                         } else {
 655                                 Logger::debug('Other queue entries need to be processed first.', ['id' => $object_data['entry-id']]);
 656                         }
 657                         return false;
 658                 }
 659
 660                 if (!empty($activity['recursion-depth'])) {
 661                         $object_data['recursion-depth'] = $activity['recursion-depth'];
 662                 }
 663
 664                 if (in_array('as:Question', [$object_data['object_type'] ?? '', $object_data['object_object_type'] ?? ''])) {
 665                         self::storeUnhandledActivity(false, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 666                 }
 667
 668                 if (!self::routeActivities($object_data, $type, $push)) {
 669                         self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 670                         Queue::remove($object_data);
 671                 }
 672                 return true;
 673         }
 674
 675         /**
 676          * Route activities
 677          *
 678          * @param array  $object_data
 679          * @param string $type
 680          * @param bool   $push
 681          * @param bool   $fetch_parents
 682          *
 683          * @return boolean Could the activity be routed?
 684          */
 685         public static function routeActivities(array $object_data, string $type, bool $push, bool $fetch_parents = true): bool
 686         {
 687                 $activity = $object_data['object_activity']     ?? [];
 688
 689                 switch ($type) {
 690                         case 'as:Create':
 691                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 692                                         $item = ActivityPub\Processor::createItem($object_data, $fetch_parents);
 693                                         ActivityPub\Processor::postItem($object_data, $item);
 694                                 } elseif (in_array($object_data['object_type'], ['pt:CacheFile'])) {
 695                                         // Unhandled Peertube activity
 696                                         Queue::remove($object_data);
 697                                 } else {
 698                                         return false;
 699                                 }
 700                                 break;
 701
 702                         case 'as:Invite':
 703                                 if (in_array($object_data['object_type'], ['as:Event'])) {
 704                                         $item = ActivityPub\Processor::createItem($object_data, $fetch_parents);
 705                                         ActivityPub\Processor::postItem($object_data, $item);
 706                                 } else {
 707                                         return false;
 708                                 }
 709                                 break;
 710
 711                         case 'as:Add':
 712                                 if ($object_data['object_type'] == 'as:tag') {
 713                                         ActivityPub\Processor::addTag($object_data);
 714                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 715                                         ActivityPub\Processor::addToFeaturedCollection($object_data);
 716                                 } elseif ($object_data['object_type'] == '') {
 717                                         // The object type couldn't be determined. We don't have it and we can't fetch it. We ignore this activity.
 718                                         Queue::remove($object_data);
 719                                 } else {
 720                                         return false;
 721                                 }
 722                                 break;
 723
 724                         case 'as:Announce':
 725                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 726                                         $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 727                                         $object_data['thread-completion'] = Contact::getIdForURL($actor);
 728                                         $object_data['completion-mode']   = self::COMPLETION_ANNOUCE;
 729
 730                                         if (!Post::exists(['uri' => $object_data['id'], 'uid' => 0])) {
 731                                                 $item = ActivityPub\Processor::createItem($object_data, $fetch_parents);
 732                                                 if (empty($item)) {
 733                                                         Logger::debug('announced id was not created', ['id' => $object_data['id']]);
 734                                                         return false;
 735                                                 }
 736
 737                                                 $item['post-reason'] = Item::PR_ANNOUNCEMENT;
 738                                                 ActivityPub\Processor::postItem($object_data, $item);
 739                                                 Logger::debug('Created announced id', ['id' => $object_data['id']]);
 740                                         } else {
 741                                                 Logger::info('Announced id already exists', ['id' => $object_data['id']]);
 742                                                 Queue::remove($object_data);
 743                                         }
 744
 745                                         if (!empty($activity)) {
 746                                                 $announce_object_data = self::processObject($activity);
 747                                                 $announce_object_data['name'] = $type;
 748                                                 $announce_object_data['author'] = $actor;
 749                                                 $announce_object_data['object_id'] = $object_data['id'];
 750                                                 $announce_object_data['object_type'] = $object_data['object_type'];
 751                                                 $announce_object_data['push'] = $push;
 752                                                 Logger::debug('Create announce activity', ['id' => $announce_object_data['id'], 'object_data' => $announce_object_data]);
 753
 754                                                 if (!empty($object_data['raw'])) {
 755                                                         $announce_object_data['raw'] = $object_data['raw'];
 756                                                 }
 757                                                 if (!empty($object_data['raw-object'])) {
 758                                                         $announce_object_data['raw-object'] = $object_data['raw-object'];
 759                                                 }
 760                                                 ActivityPub\Processor::createActivity($announce_object_data, Activity::ANNOUNCE);
 761                                         }
 762                                 } else {
 763                                         return false;
 764                                 }
 765                                 break;
 766
 767                         case 'as:Like':
 768                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 769                                         ActivityPub\Processor::createActivity($object_data, Activity::LIKE);
 770                                 } elseif ($object_data['object_type'] == '') {
 771                                         // The object type couldn't be determined. We don't have it and we can't fetch it. We ignore this activity.
 772                                         Queue::remove($object_data);
 773                                 } else {
 774                                         return false;
 775                                 }
 776                                 break;
 777
 778                         case 'as:Dislike':
 779                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 780                                         ActivityPub\Processor::createActivity($object_data, Activity::DISLIKE);
 781                                 } elseif ($object_data['object_type'] == '') {
 782                                         // The object type couldn't be determined. We don't have it and we can't fetch it. We ignore this activity.
 783                                         Queue::remove($object_data);
 784                                 } else {
 785                                         return false;
 786                                 }
 787                                 break;
 788
 789                         case 'as:TentativeAccept':
 790                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 791                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDMAYBE);
 792                                 } else {
 793                                         return false;
 794                                 }
 795                                 break;
 796
 797                         case 'as:Update':
 798                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 799                                         ActivityPub\Processor::updateItem($object_data);
 800                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 801                                         ActivityPub\Processor::updatePerson($object_data);
 802                                 } elseif (in_array($object_data['object_type'], ['pt:CacheFile'])) {
 803                                         // Unhandled Peertube activity
 804                                         Queue::remove($object_data);
 805                                 } else {
 806                                         return false;
 807                                 }
 808                                 break;
 809
 810                         case 'as:Delete':
 811                                 if (in_array($object_data['object_type'], array_merge(['as:Tombstone'], self::CONTENT_TYPES))) {
 812                                         ActivityPub\Processor::deleteItem($object_data);
 813                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 814                                         ActivityPub\Processor::deletePerson($object_data);
 815                                 } elseif ($object_data['object_type'] == '') {
 816                                         // The object type couldn't be determined. Most likely we don't have it here. We ignore this activity.
 817                                         Queue::remove($object_data);
 818                                 } else {
 819                                         return false;
 820                                 }
 821                                 break;
 822
 823                         case 'as:Block':
 824                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 825                                         ActivityPub\Processor::blockAccount($object_data);
 826                                 } else {
 827                                         return false;
 828                                 }
 829                                 break;
 830
 831                         case 'as:Remove':
 832                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 833                                         ActivityPub\Processor::removeFromFeaturedCollection($object_data);
 834                                 } elseif ($object_data['object_type'] == '') {
 835                                         // The object type couldn't be determined. We don't have it and we can't fetch it. We ignore this activity.
 836                                         Queue::remove($object_data);
 837                                 } else {
 838                                         return false;
 839                                 }
 840                                 break;
 841
 842                         case 'as:Follow':
 843                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 844                                         ActivityPub\Processor::followUser($object_data);
 845                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 846                                         $object_data['reply-to-id'] = $object_data['object_id'];
 847                                         ActivityPub\Processor::createActivity($object_data, Activity::FOLLOW);
 848                                 } else {
 849                                         return false;
 850                                 }
 851                                 break;
 852
 853                         case 'as:Accept':
 854                                 if ($object_data['object_type'] == 'as:Follow') {
 855                                         ActivityPub\Processor::acceptFollowUser($object_data);
 856                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 857                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTEND);
 858                                 } else {
 859                                         return false;
 860                                 }
 861                                 break;
 862
 863                         case 'as:Reject':
 864                                 if ($object_data['object_type'] == 'as:Follow') {
 865                                         ActivityPub\Processor::rejectFollowUser($object_data);
 866                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 867                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDNO);
 868                                 } else {
 869                                         return false;
 870                                 }
 871                                 break;
 872
 873                         case 'as:Undo':
 874                                 if (($object_data['object_type'] == 'as:Follow') &&
 875                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 876                                         ActivityPub\Processor::undoFollowUser($object_data);
 877                                 } elseif (($object_data['object_type'] == 'as:Follow') &&
 878                                         in_array($object_data['object_object_type'], self::CONTENT_TYPES)) {
 879                                         ActivityPub\Processor::undoActivity($object_data);
 880                                 } elseif (($object_data['object_type'] == 'as:Accept') &&
 881                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 882                                         ActivityPub\Processor::rejectFollowUser($object_data);
 883                                 } elseif (($object_data['object_type'] == 'as:Block') &&
 884                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 885                                         ActivityPub\Processor::unblockAccount($object_data);
 886                                 } elseif (in_array($object_data['object_type'], array_merge(self::ACTIVITY_TYPES, ['as:Announce'])) &&
 887                                         in_array($object_data['object_object_type'], array_merge(['as:Tombstone'], self::CONTENT_TYPES))) {
 888                                         ActivityPub\Processor::undoActivity($object_data);
 889                                 } elseif (in_array($object_data['object_type'], array_merge(self::ACTIVITY_TYPES, ['as:Announce', 'as:Create', ''])) &&
 890                                         empty($object_data['object_object_type'])) {
 891                                         // We cannot detect the target object. So we can ignore it.
 892                                         Queue::remove($object_data);
 893                                 } elseif (in_array($object_data['object_type'], ['as:Create']) &&
 894                                         in_array($object_data['object_object_type'], ['pt:CacheFile'])) {
 895                                         // Unhandled Peertube activity
 896                                         Queue::remove($object_data);
 897                                 } else {
 898                                         return false;
 899                                 }
 900                                 break;
 901
 902                         case 'as:View':
 903                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 904                                         ActivityPub\Processor::createActivity($object_data, Activity::VIEW);
 905                                 } elseif ($object_data['object_type'] == '') {
 906                                         // The object type couldn't be determined. Most likely we don't have it here. We ignore this activity.
 907                                         Queue::remove($object_data);
 908                                 } else {
 909                                         return false;
 910                                 }
 911                                 break;
 912
 913                         case 'litepub:EmojiReact':
 914                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 915                                         ActivityPub\Processor::createActivity($object_data, Activity::EMOJIREACT);
 916                                 } elseif ($object_data['object_type'] == '') {
 917                                         // The object type couldn't be determined. We don't have it and we can't fetch it. We ignore this activity.
 918                                         Queue::remove($object_data);
 919                                 } else {
 920                                         return false;
 921                                 }
 922                                 break;
 923
 924                         default:
 925                                 Logger::info('Unknown activity: ' . $type . ' ' . $object_data['object_type']);
 926                                 return false;
 927                 }
 928                 return true;
 929         }
 930
 931         /**
 932          * Stores unhandled or unknown Activities as a file
 933          *
 934          * @param boolean $unknown      "true" if the activity is unknown, "false" if it is unhandled
 935          * @param string  $type         Activity type
 936          * @param array   $object_data  Preprocessed array that is generated out of the received activity
 937          * @param array   $activity     Array with activity data
 938          * @param string  $body         The unprocessed body
 939          * @param integer $uid          User ID
 940          * @param boolean $trust_source Do we trust the source?
 941          * @param boolean $push         Message had been pushed to our system
 942          * @param array   $signer       The signer of the post
 943          * @return void
 944          */
 945         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 = [])
 946         {
 947                 if (!DI::config()->get('debug', 'ap_log_unknown')) {
 948                         return;
 949                 }
 950
 951                 $file = ($unknown  ? 'unknown-' : 'unhandled-') . str_replace(':', '-', $type) . '-';
 952
 953                 if (!empty($object_data['object_type'])) {
 954                         $file .= str_replace(':', '-', $object_data['object_type']) . '-';
 955                 }
 956
 957                 if (!empty($object_data['object_object_type'])) {
 958                         $file .= str_replace(':', '-', $object_data['object_object_type']) . '-';
 959                 }
 960
 961                 $tempfile = tempnam(System::getTempPath(), $file);
 962                 file_put_contents($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));
 963                 Logger::notice('Unknown activity stored', ['type' => $type, 'object_type' => $object_data['object_type'], $object_data['object_object_type'] ?? '', 'file' => $tempfile]);
 964         }
 965
 966         /**
 967          * Fetch a user id from an activity array
 968          *
 969          * @param array  $activity
 970          * @param string $actor
 971          *
 972          * @return int   user id
 973          */
 974         public static function getBestUserForActivity(array $activity): int
 975         {
 976                 $uid = 0;
 977                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id') ?? '';
 978
 979                 $receivers = self::getReceivers($activity, $actor);
 980                 foreach ($receivers as $receiver) {
 981                         if ($receiver['type'] == self::TARGET_GLOBAL) {
 982                                 return 0;
 983                         }
 984                         if (empty($uid) || ($receiver['type'] == self::TARGET_TO)) {
 985                                 $uid = $receiver['uid'];
 986                         }
 987                 }
 988
 989                 // When we haven't found any user yet, we just chose a user who most likely could have access to the content
 990                 if (empty($uid)) {
 991                         $contact = Contact::selectFirst(['uid'], ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND]]);
 992                         if (!empty($contact['uid'])) {
 993                                 $uid = $contact['uid'];
 994                         }
 995                 }
 996
 997                 return $uid;
 998         }
 999
1000         // @TODO Missing documentation
1001         public static function getReceiverURL(array $activity): array
1002         {
1003                 $urls = [];
1004
1005                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
1006                         $receiver_list = JsonLD::fetchElementArray($activity, $element, '@id');
1007                         if (empty($receiver_list)) {
1008                                 continue;
1009                         }
1010
1011                         foreach ($receiver_list as $receiver) {
1012                                 if ($receiver == self::PUBLIC_COLLECTION) {
1013                                         $receiver = ActivityPub::PUBLIC_COLLECTION;
1014                                 }
1015                                 $urls[$element][] = $receiver;
1016                         }
1017                 }
1018
1019                 return $urls;
1020         }
1021
1022         /**
1023          * Fetch the receiver list from an activity array
1024          *
1025          * @param array   $activity
1026          * @param string  $actor
1027          * @param array   $tags
1028          * @param boolean $fetch_unlisted
1029          *
1030          * @return array with receivers (user id)
1031          * @throws \Exception
1032          */
1033         private static function getReceivers(array $activity, string $actor, array $tags = [], bool $fetch_unlisted = false): array
1034         {
1035                 $reply = $receivers = $profile = [];
1036
1037                 // When it is an answer, we inherite the receivers from the parent
1038                 $replyto = JsonLD::fetchElement($activity, 'as:inReplyTo', '@id');
1039                 if (!empty($replyto)) {
1040                         $reply = [$replyto];
1041
1042                         // Fix possibly wrong item URI (could be an answer to a plink uri)
1043                         $fixedReplyTo = Item::getURIByLink($replyto);
1044                         if (!empty($fixedReplyTo)) {
1045                                 $reply[] = $fixedReplyTo;
1046                         }
1047                 }
1048
1049                 // Fetch all posts that refer to the object id
1050                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
1051                 if (!empty($object_id)) {
1052                         $reply[] = $object_id;
1053                 }
1054
1055                 if (!empty($reply)) {
1056                         $parents = Post::select(['uid'], DBA::mergeConditions(['uri' => $reply], ["`uid` != ?", 0]));
1057                         while ($parent = Post::fetch($parents)) {
1058                                 $receivers[$parent['uid']] = ['uid' => $parent['uid'], 'type' => self::TARGET_ANSWER];
1059                         }
1060                         DBA::close($parents);
1061                 }
1062
1063                 if (!empty($actor)) {
1064                         $profile   = APContact::getByURL($actor);
1065                         $followers = $profile['followers'] ?? '';
1066                         $is_forum  = ($actor['type'] ?? '') == 'Group';
1067                         Logger::info('Got actor and followers', ['actor' => $actor, 'followers' => $followers]);
1068                 } else {
1069                         Logger::info('Empty actor', ['activity' => $activity]);
1070                         $followers = '';
1071                         $is_forum  = false;
1072                 }
1073
1074                 // We have to prevent false follower assumptions upon thread completions
1075                 $follower_target = empty($activity['thread-completion']) ? self::TARGET_FOLLOWER : self::TARGET_UNKNOWN;
1076
1077                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
1078                         $receiver_list = JsonLD::fetchElementArray($activity, $element, '@id');
1079                         if (empty($receiver_list)) {
1080                                 continue;
1081                         }
1082
1083                         foreach ($receiver_list as $receiver) {
1084                                 if ($receiver == self::PUBLIC_COLLECTION) {
1085                                         $receivers[0] = ['uid' => 0, 'type' => self::TARGET_GLOBAL];
1086                                 }
1087
1088                                 // Add receiver "-1" for unlisted posts
1089                                 if ($fetch_unlisted && ($receiver == self::PUBLIC_COLLECTION) && ($element == 'as:cc')) {
1090                                         $receivers[-1] = ['uid' => -1, 'type' => self::TARGET_GLOBAL];
1091                                 }
1092
1093                                 // Fetch the receivers for the public and the followers collection
1094                                 if ((($receiver == $followers) || (($receiver == self::PUBLIC_COLLECTION) && !$is_forum)) && !empty($actor)) {
1095                                         $receivers = self::getReceiverForActor($actor, $tags, $receivers, $follower_target, $profile);
1096                                         continue;
1097                                 }
1098
1099                                 // Fetching all directly addressed receivers
1100                                 $condition = ['self' => true, 'nurl' => Strings::normaliseLink($receiver)];
1101                                 $contact = DBA::selectFirst('contact', ['uid', 'contact-type'], $condition);
1102                                 if (!DBA::isResult($contact)) {
1103                                         continue;
1104                                 }
1105
1106                                 // Check if the potential receiver is following the actor
1107                                 // Exception: The receiver is targetted via "to" or this is a comment
1108                                 if ((($element != 'as:to') && empty($replyto)) || ($contact['contact-type'] == Contact::TYPE_COMMUNITY)) {
1109                                         $networks = Protocol::FEDERATED;
1110                                         $condition = ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
1111                                                 'network' => $networks, 'archive' => false, 'pending' => false, 'uid' => $contact['uid']];
1112
1113                                         // Forum posts are only accepted from forum contacts
1114                                         if ($contact['contact-type'] == Contact::TYPE_COMMUNITY) {
1115                                                 $condition['rel'] = [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER];
1116                                         }
1117
1118                                         if (!DBA::exists('contact', $condition)) {
1119                                                 continue;
1120                                         }
1121                                 }
1122
1123                                 $type = $receivers[$contact['uid']]['type'] ?? self::TARGET_UNKNOWN;
1124                                 if (in_array($type, [self::TARGET_UNKNOWN, self::TARGET_FOLLOWER, self::TARGET_ANSWER, self::TARGET_GLOBAL])) {
1125                                         switch ($element) {
1126                                                 case 'as:to':
1127                                                         $type = self::TARGET_TO;
1128                                                         break;
1129                                                 case 'as:cc':
1130                                                         $type = self::TARGET_CC;
1131                                                         break;
1132                                                 case 'as:bto':
1133                                                         $type = self::TARGET_BTO;
1134                                                         break;
1135                                                 case 'as:bcc':
1136                                                         $type = self::TARGET_BCC;
1137                                                         break;
1138                                         }
1139
1140                                         $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $type];
1141                                 }
1142                         }
1143                 }
1144
1145                 self::switchContacts($receivers, $actor);
1146
1147                 return $receivers;
1148         }
1149
1150         /**
1151          * Fetch the receiver list of a given actor
1152          *
1153          * @param string  $actor
1154          * @param array   $tags
1155          * @param array   $receivers
1156          * @param integer $target_type
1157          * @param array   $profile
1158          *
1159          * @return array with receivers (user id)
1160          * @throws \Exception
1161          */
1162         private static function getReceiverForActor(string $actor, array $tags, array $receivers, int $target_type, array $profile): array
1163         {
1164                 $basecondition = ['rel' => [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER],
1165                         'network' => Protocol::FEDERATED, 'archive' => false, 'pending' => false];
1166
1167                 if (!empty($profile['uri-id'])) {
1168                         $condition = DBA::mergeConditions($basecondition, ["`uri-id` = ? AND `uid` != ?", $profile['uri-id'], 0]);
1169                         $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
1170                         while ($contact = DBA::fetch($contacts)) {
1171                                 if (empty($receivers[$contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
1172                                         $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $target_type];
1173                                 }
1174                         }
1175                         DBA::close($contacts);
1176                 } else {
1177                         // This part will only be called while post update 1426 wasn't finished
1178                         $condition = DBA::mergeConditions($basecondition, ["`nurl` = ? AND `uid` != ?", Strings::normaliseLink($actor), 0]);
1179                         $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
1180                         while ($contact = DBA::fetch($contacts)) {
1181                                 if (empty($receivers[$contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
1182                                         $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $target_type];
1183                                 }
1184                         }
1185                         DBA::close($contacts);
1186
1187                         // The queries are split because of performance issues
1188                         $condition = DBA::mergeConditions($basecondition, ["`alias` IN (?, ?) AND `uid` != ?", Strings::normaliseLink($actor), $actor, 0]);
1189                         $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
1190                         while ($contact = DBA::fetch($contacts)) {
1191                                 if (empty($receivers[$contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
1192                                         $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $target_type];
1193                                 }
1194                         }
1195                         DBA::close($contacts);
1196                 }
1197                 return $receivers;
1198         }
1199
1200         /**
1201          * Tests if the contact is a valid receiver for this actor
1202          *
1203          * @param array  $contact
1204          * @param array  $tags
1205          *
1206          * @return bool with receivers (user id)
1207          * @throws \Exception
1208          */
1209         private static function isValidReceiverForActor(array $contact, array $tags): bool
1210         {
1211                 // Are we following the contact? Then this is a valid receiver
1212                 if (in_array($contact['rel'], [Contact::SHARING, Contact::FRIEND])) {
1213                         return true;
1214                 }
1215
1216                 // When the possible receiver isn't a community, then it is no valid receiver
1217                 $owner = User::getOwnerDataById($contact['uid']);
1218                 if (empty($owner) || ($owner['contact-type'] != Contact::TYPE_COMMUNITY)) {
1219                         return false;
1220                 }
1221
1222                 // Is the community account tagged?
1223                 foreach ($tags as $tag) {
1224                         if ($tag['type'] != 'Mention') {
1225                                 continue;
1226                         }
1227
1228                         if (Strings::compareLink($tag['href'], $owner['url'])) {
1229                                 return true;
1230                         }
1231                 }
1232
1233                 return false;
1234         }
1235
1236         /**
1237          * Switches existing contacts to ActivityPub
1238          *
1239          * @param integer $cid Contact ID
1240          * @param integer $uid User ID
1241          * @param string  $url Profile URL
1242          * @return void
1243          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1244          * @throws \ImagickException
1245          */
1246         public static function switchContact(int $cid, int $uid, string $url)
1247         {
1248                 if (DBA::exists('contact', ['id' => $cid, 'network' => Protocol::ACTIVITYPUB])) {
1249                         Logger::info('Contact is already ActivityPub', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
1250                         return;
1251                 }
1252
1253                 if (Contact::updateFromProbe($cid)) {
1254                         Logger::info('Update was successful', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
1255                 }
1256
1257                 // Send a new follow request to be sure that the connection still exists
1258                 if (($uid != 0) && DBA::exists('contact', ['id' => $cid, 'rel' => [Contact::SHARING, Contact::FRIEND], 'network' => Protocol::ACTIVITYPUB])) {
1259                         Logger::info('Contact had been switched to ActivityPub. Sending a new follow request.', ['uid' => $uid, 'url' => $url]);
1260                         ActivityPub\Transmitter::sendActivity('Follow', $url, $uid);
1261                 }
1262         }
1263
1264         /**
1265          * @TODO Fix documentation and type-hints
1266          *
1267          * @param $receivers
1268          * @param $actor
1269          * @return void
1270          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1271          * @throws \ImagickException
1272          */
1273         private static function switchContacts($receivers, $actor)
1274         {
1275                 if (empty($actor)) {
1276                         return;
1277                 }
1278
1279                 foreach ($receivers as $receiver) {
1280                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver['uid'], 'network' => Protocol::OSTATUS, 'nurl' => Strings::normaliseLink($actor)]);
1281                         if (DBA::isResult($contact)) {
1282                                 self::switchContact($contact['id'], $receiver['uid'], $actor);
1283                         }
1284
1285                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver['uid'], 'network' => Protocol::OSTATUS, 'alias' => [Strings::normaliseLink($actor), $actor]]);
1286                         if (DBA::isResult($contact)) {
1287                                 self::switchContact($contact['id'], $receiver['uid'], $actor);
1288                         }
1289                 }
1290         }
1291
1292         /**
1293          * @TODO Fix documentation and type-hints
1294          *
1295          * @param       $object_data
1296          * @param array $activity
1297          *
1298          * @return mixed
1299          */
1300         private static function addActivityFields($object_data, array $activity)
1301         {
1302                 if (!empty($activity['published']) && empty($object_data['published'])) {
1303                         $object_data['published'] = JsonLD::fetchElement($activity, 'as:published', '@value');
1304                 }
1305
1306                 if (!empty($activity['diaspora:guid']) && empty($object_data['diaspora:guid'])) {
1307                         $object_data['diaspora:guid'] = JsonLD::fetchElement($activity, 'diaspora:guid', '@value');
1308                 }
1309
1310                 $object_data['service'] = JsonLD::fetchElement($activity, 'as:instrument', 'as:name', '@type', 'as:Service');
1311                 $object_data['service'] = JsonLD::fetchElement($object_data, 'service', '@value');
1312
1313                 if (!empty($object_data['object_id'])) {
1314                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
1315                         $objectId = Item::getURIByLink($object_data['object_id']);
1316                         if (!empty($objectId) && ($object_data['object_id'] != $objectId)) {
1317                                 Logger::notice('Fix wrong object-id', ['received' => $object_data['object_id'], 'correct' => $objectId]);
1318                                 $object_data['object_id'] = $objectId;
1319                         }
1320                 }
1321
1322                 return $object_data;
1323         }
1324
1325         /**
1326          * Fetches the object data from external ressources if needed
1327          *
1328          * @param string  $object_id    Object ID of the the provided object
1329          * @param array   $object       The provided object array
1330          * @param boolean $trust_source Do we trust the provided object?
1331          * @param integer $uid          User ID for the signature that we use to fetch data
1332          *
1333          * @return array|false with trusted and valid object data
1334          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1335          * @throws \ImagickException
1336          */
1337         private static function fetchObject(string $object_id, array $object = [], bool $trust_source = false, int $uid = 0)
1338         {
1339                 // By fetching the type we check if the object is complete.
1340                 $type = JsonLD::fetchElement($object, '@type');
1341
1342                 if (!$trust_source || empty($type)) {
1343                         $data = Processor::fetchCachedActivity($object_id, $uid);
1344                         if (!empty($data)) {
1345                                 $object = JsonLD::compact($data);
1346                                 Logger::info('Fetched content for ' . $object_id);
1347                         } else {
1348                                 Logger::info('Empty content for ' . $object_id . ', check if content is available locally.');
1349
1350                                 $item = Post::selectFirst(Item::DELIVER_FIELDLIST, ['uri' => $object_id]);
1351                                 if (!DBA::isResult($item)) {
1352                                         Logger::info('Object with url ' . $object_id . ' was not found locally.');
1353                                         return false;
1354                                 }
1355                                 Logger::info('Using already stored item for url ' . $object_id);
1356                                 $data = ActivityPub\Transmitter::createNote($item);
1357                                 $object = JsonLD::compact($data);
1358                         }
1359
1360                         $id = JsonLD::fetchElement($object, '@id');
1361                         if (empty($id)) {
1362                                 Logger::info('Empty id');
1363                                 return false;
1364                         }
1365
1366                         if ($id != $object_id) {
1367                                 Logger::info('Fetched id differs from provided id', ['provided' => $object_id, 'fetched' => $id]);
1368                                 return false;
1369                         }
1370                 } else {
1371                         Logger::info('Using original object for url ' . $object_id);
1372                 }
1373
1374                 $type = JsonLD::fetchElement($object, '@type');
1375                 if (empty($type)) {
1376                         Logger::info('Empty type');
1377                         return false;
1378                 }
1379
1380                 // Lemmy is resharing "create" activities instead of content
1381                 // We fetch the content from the activity.
1382                 if (in_array($type, ['as:Create'])) {
1383                         $object = $object['as:object'];
1384                         $type = JsonLD::fetchElement($object, '@type');
1385                         if (empty($type)) {
1386                                 Logger::info('Empty type');
1387                                 return false;
1388                         }
1389                         $object_data = self::processObject($object);
1390                 }
1391
1392                 // We currently don't handle 'pt:CacheFile', but with this step we avoid logging
1393                 if (in_array($type, self::CONTENT_TYPES) || ($type == 'pt:CacheFile')) {
1394                         $object_data = self::processObject($object);
1395
1396                         if (!empty($data)) {
1397                                 $object_data['raw-object'] = json_encode($data);
1398                         }
1399                         return $object_data;
1400                 }
1401
1402                 if ($type == 'as:Announce') {
1403                         $object_id = JsonLD::fetchElement($object, 'object', '@id');
1404                         if (empty($object_id) || !is_string($object_id)) {
1405                                 return false;
1406                         }
1407                         return self::fetchObject($object_id, [], false, $uid);
1408                 }
1409
1410                 Logger::info('Unhandled object type: ' . $type);
1411                 return false;
1412         }
1413
1414         /**
1415          * Converts the language element (Used by Peertube)
1416          *
1417          * @param array $languages
1418          * @return array Languages
1419          */
1420         public static function processLanguages(array $languages): array
1421         {
1422                 if (empty($languages)) {
1423                         return [];
1424                 }
1425
1426                 $language_list = [];
1427
1428                 foreach ($languages as $language) {
1429                         if (!empty($language['_:identifier']) && !empty($language['as:name'])) {
1430                                 $language_list[$language['_:identifier']] = $language['as:name'];
1431                         }
1432                 }
1433                 return $language_list;
1434         }
1435
1436         /**
1437          * Convert tags from JSON-LD format into a simplified format
1438          *
1439          * @param array $tags Tags in JSON-LD format
1440          *
1441          * @return array with tags in a simplified format
1442          */
1443         public static function processTags(array $tags): array
1444         {
1445                 $taglist = [];
1446
1447                 foreach ($tags as $tag) {
1448                         if (empty($tag)) {
1449                                 continue;
1450                         }
1451
1452                         $element = ['type' => str_replace('as:', '', JsonLD::fetchElement($tag, '@type')),
1453                                 'href' => JsonLD::fetchElement($tag, 'as:href', '@id'),
1454                                 'name' => JsonLD::fetchElement($tag, 'as:name', '@value')];
1455
1456                         if (empty($element['type'])) {
1457                                 continue;
1458                         }
1459
1460                         if (empty($element['href'])) {
1461                                 $element['href'] = $element['name'];
1462                         }
1463
1464                         $taglist[] = $element;
1465                 }
1466                 return $taglist;
1467         }
1468
1469         /**
1470          * Convert emojis from JSON-LD format into a simplified format
1471          *
1472          * @param array $emojis
1473          * @return array with emojis in a simplified format
1474          */
1475         private static function processEmojis(array $emojis): array
1476         {
1477                 $emojilist = [];
1478
1479                 foreach ($emojis as $emoji) {
1480                         if (empty($emoji) || (JsonLD::fetchElement($emoji, '@type') != 'toot:Emoji') || empty($emoji['as:icon'])) {
1481                                 continue;
1482                         }
1483
1484                         $url = JsonLD::fetchElement($emoji['as:icon'], 'as:url', '@id');
1485                         $element = ['name' => JsonLD::fetchElement($emoji, 'as:name', '@value'),
1486                                 'href' => $url];
1487
1488                         $emojilist[] = $element;
1489                 }
1490
1491                 return $emojilist;
1492         }
1493
1494         /**
1495          * Convert attachments from JSON-LD format into a simplified format
1496          *
1497          * @param array $attachments Attachments in JSON-LD format
1498          *
1499          * @return array Attachments in a simplified format
1500          */
1501         private static function processAttachments(array $attachments): array
1502         {
1503                 $attachlist = [];
1504
1505                 // Removes empty values
1506                 $attachments = array_filter($attachments);
1507
1508                 foreach ($attachments as $attachment) {
1509                         switch (JsonLD::fetchElement($attachment, '@type')) {
1510                                 case 'as:Page':
1511                                         $pageUrl = null;
1512                                         $pageImage = null;
1513
1514                                         $urls = JsonLD::fetchElementArray($attachment, 'as:url');
1515                                         foreach ($urls as $url) {
1516                                                 // Single scalar URL case
1517                                                 if (is_string($url)) {
1518                                                         $pageUrl = $url;
1519                                                         continue;
1520                                                 }
1521
1522                                                 $href = JsonLD::fetchElement($url, 'as:href', '@id');
1523                                                 $mediaType = JsonLD::fetchElement($url, 'as:mediaType', '@value');
1524                                                 if (Strings::startsWith($mediaType, 'image')) {
1525                                                         $pageImage = $href;
1526                                                 } else {
1527                                                         $pageUrl = $href;
1528                                                 }
1529                                         }
1530
1531                                         $attachlist[] = [
1532                                                 'type'  => 'link',
1533                                                 'title' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1534                                                 'desc'  => JsonLD::fetchElement($attachment, 'as:summary', '@value'),
1535                                                 'url'   => $pageUrl,
1536                                                 'image' => $pageImage,
1537                                         ];
1538                                         break;
1539                                 case 'as:Image':
1540                                         $mediaType = JsonLD::fetchElement($attachment, 'as:mediaType', '@value');
1541                                         $imageFullUrl = JsonLD::fetchElement($attachment, 'as:url', '@id');
1542                                         $imagePreviewUrl = null;
1543                                         // Multiple URLs?
1544                                         if (!$imageFullUrl && ($urls = JsonLD::fetchElementArray($attachment, 'as:url'))) {
1545                                                 $imageVariants = [];
1546                                                 $previewVariants = [];
1547                                                 foreach ($urls as $url) {
1548                                                         // Scalar URL, no discrimination possible
1549                                                         if (is_string($url)) {
1550                                                                 $imageFullUrl = $url;
1551                                                                 continue;
1552                                                         }
1553
1554                                                         // Not sure what to do with a different Link media type than the base Image, we skip
1555                                                         if ($mediaType != JsonLD::fetchElement($url, 'as:mediaType', '@value')) {
1556                                                                 continue;
1557                                                         }
1558
1559                                                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1560
1561                                                         // Default URL choice if no discriminating width is provided
1562                                                         $imageFullUrl = $href ?? $imageFullUrl;
1563
1564                                                         $width = intval(JsonLD::fetchElement($url, 'as:width', '@value') ?? 1);
1565
1566                                                         if ($href && $width) {
1567                                                                 $imageVariants[$width] = $href;
1568                                                                 // 632 is the ideal width for full screen frio posts, we compute the absolute distance to it
1569                                                                 $previewVariants[abs(632 - $width)] = $href;
1570                                                         }
1571                                                 }
1572
1573                                                 if ($imageVariants) {
1574                                                         // Taking the maximum size image
1575                                                         ksort($imageVariants);
1576                                                         $imageFullUrl = array_pop($imageVariants);
1577
1578                                                         // Taking the minimum number distance to the target distance
1579                                                         ksort($previewVariants);
1580                                                         $imagePreviewUrl = array_shift($previewVariants);
1581                                                 }
1582
1583                                                 unset($imageVariants);
1584                                                 unset($previewVariants);
1585                                         }
1586
1587                                         $attachlist[] = [
1588                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1589                                                 'mediaType' => $mediaType,
1590                                                 'name'  => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1591                                                 'url'   => $imageFullUrl,
1592                                                 'image' => $imagePreviewUrl !== $imageFullUrl ? $imagePreviewUrl : null,
1593                                         ];
1594                                         break;
1595                                 default:
1596                                         $attachlist[] = [
1597                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1598                                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType', '@value'),
1599                                                 'name' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1600                                                 'url' => JsonLD::fetchElement($attachment, 'as:url', '@id'),
1601                                                 'height' => JsonLD::fetchElement($attachment, 'as:height', '@value'),
1602                                                 'width' => JsonLD::fetchElement($attachment, 'as:width', '@value'),
1603                                                 'image' => JsonLD::fetchElement($attachment, 'as:image', '@id')
1604                                         ];
1605                         }
1606                 }
1607
1608                 return $attachlist;
1609         }
1610
1611         /**
1612          * Convert questions from JSON-LD format into a simplified format
1613          *
1614          * @param array $object
1615          *
1616          * @return array Questions in a simplified format
1617          */
1618         private static function processQuestion(array $object): array
1619         {
1620                 $question = [];
1621
1622                 if (!empty($object['as:oneOf'])) {
1623                         $question['multiple'] = false;
1624                         $options = JsonLD::fetchElementArray($object, 'as:oneOf') ?? [];
1625                 } elseif (!empty($object['as:anyOf'])) {
1626                         $question['multiple'] = true;
1627                         $options = JsonLD::fetchElementArray($object, 'as:anyOf') ?? [];
1628                 } else {
1629                         return [];
1630                 }
1631
1632                 $closed = JsonLD::fetchElement($object, 'as:closed', '@value');
1633                 if (!empty($closed)) {
1634                         $question['end-time'] = $closed;
1635                 } else {
1636                         $question['end-time'] = JsonLD::fetchElement($object, 'as:endTime', '@value');
1637                 }
1638
1639                 $question['voters']  = (int)JsonLD::fetchElement($object, 'toot:votersCount', '@value');
1640                 $question['options'] = [];
1641
1642                 $voters = 0;
1643
1644                 foreach ($options as $option) {
1645                         if (JsonLD::fetchElement($option, '@type') != 'as:Note') {
1646                                 continue;
1647                         }
1648
1649                         $name = JsonLD::fetchElement($option, 'as:name', '@value');
1650
1651                         if (empty($option['as:replies'])) {
1652                                 continue;
1653                         }
1654
1655                         $replies = JsonLD::fetchElement($option['as:replies'], 'as:totalItems', '@value');
1656
1657                         $question['options'][] = ['name' => $name, 'replies' => $replies];
1658
1659                         $voters += (int)$replies;
1660                 }
1661
1662                 // For single choice question we can count the number of voters if not provided (like with Misskey)
1663                 if (empty($question['voters']) && !$question['multiple']) {
1664                         $question['voters'] = $voters;
1665                 }
1666
1667                 return $question;
1668         }
1669
1670         /**
1671          * Fetch the original source or content with the "language" Markdown or HTML
1672          *
1673          * @param array $object
1674          * @param array $object_data
1675          *
1676          * @return array Object data (?)
1677          * @throws \Exception
1678          */
1679         private static function getSource(array $object, array $object_data): array
1680         {
1681                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/bbcode');
1682                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1683                 if (!empty($object_data['source'])) {
1684                         return $object_data;
1685                 }
1686
1687                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/markdown');
1688                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1689                 if (!empty($object_data['source'])) {
1690                         $object_data['source'] = Markdown::toBBCode($object_data['source']);
1691                         return $object_data;
1692                 }
1693
1694                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/html');
1695                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1696                 if (!empty($object_data['source'])) {
1697                         $object_data['source'] = HTML::toBBCode($object_data['source']);
1698                         return $object_data;
1699                 }
1700
1701                 return $object_data;
1702         }
1703
1704         /**
1705          * Extracts a potential alternate URL from a list of additional URL elements
1706          *
1707          * @param array $urls
1708          * @return string
1709          */
1710         private static function extractAlternateUrl(array $urls): string
1711         {
1712                 $alternateUrl = '';
1713                 foreach ($urls as $key => $url) {
1714                         // Not a list but a single URL element
1715                         if (!is_numeric($key)) {
1716                                 continue;
1717                         }
1718
1719                         if (empty($url['@type']) || ($url['@type'] != 'as:Link')) {
1720                                 continue;
1721                         }
1722
1723                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1724                         if (empty($href)) {
1725                                 continue;
1726                         }
1727
1728                         $mediatype = JsonLD::fetchElement($url, 'as:mediaType');
1729                         if (empty($mediatype)) {
1730                                 continue;
1731                         }
1732
1733                         if ($mediatype == 'text/html') {
1734                                 $alternateUrl = $href;
1735                         }
1736                 }
1737
1738                 return $alternateUrl;
1739         }
1740
1741         /**
1742          * Check if the "as:url" element is an array with multiple links
1743          * This is the case with audio and video posts.
1744          * Then the links are added as attachments
1745          *
1746          * @param array $urls The object URL list
1747          * @return array an array of attachments
1748          */
1749         private static function processAttachmentUrls(array $urls): array
1750         {
1751                 $attachments = [];
1752                 foreach ($urls as $key => $url) {
1753                         // Not a list but a single URL element
1754                         if (!is_numeric($key)) {
1755                                 continue;
1756                         }
1757
1758                         if (empty($url['@type']) || ($url['@type'] != 'as:Link')) {
1759                                 continue;
1760                         }
1761
1762                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1763                         if (empty($href)) {
1764                                 continue;
1765                         }
1766
1767                         $mediatype = JsonLD::fetchElement($url, 'as:mediaType');
1768                         if (empty($mediatype)) {
1769                                 continue;
1770                         }
1771
1772                         $filetype = strtolower(substr($mediatype, 0, strpos($mediatype, '/')));
1773
1774                         if ($filetype == 'audio') {
1775                                 $attachments[] = ['type' => $filetype, 'mediaType' => $mediatype, 'url' => $href, 'height' => null, 'size' => null, 'name' => ''];
1776                         } elseif ($filetype == 'video') {
1777                                 $height = (int)JsonLD::fetchElement($url, 'as:height', '@value');
1778                                 // PeerTube audio-only track
1779                                 if ($height === 0) {
1780                                         continue;
1781                                 }
1782
1783                                 $size = (int)JsonLD::fetchElement($url, 'pt:size', '@value');
1784                                 $attachments[] = ['type' => $filetype, 'mediaType' => $mediatype, 'url' => $href, 'height' => $height, 'size' => $size, 'name' => ''];
1785                         } elseif (in_array($mediatype, ['application/x-bittorrent', 'application/x-bittorrent;x-scheme-handler/magnet'])) {
1786                                 $height = (int)JsonLD::fetchElement($url, 'as:height', '@value');
1787
1788                                 // For Torrent links we always store the highest resolution
1789                                 if (!empty($attachments[$mediatype]['height']) && ($height < $attachments[$mediatype]['height'])) {
1790                                         continue;
1791                                 }
1792
1793                                 $attachments[$mediatype] = ['type' => $mediatype, 'mediaType' => $mediatype, 'url' => $href, 'height' => $height, 'size' => null, 'name' => ''];
1794                         } elseif ($mediatype == 'application/x-mpegURL') {
1795                                 // PeerTube exception, actual video link is in the tags of this URL element
1796                                 $attachments = array_merge($attachments, self::processAttachmentUrls($url['as:tag']));
1797                         }
1798                 }
1799
1800                 return array_values($attachments);
1801         }
1802
1803         /**
1804          * Fetches data from the object part of an activity
1805          *
1806          * @param array $object
1807          *
1808          * @return array|bool Object data or FALSE if $object does not contain @id element
1809          * @throws \Exception
1810          */
1811         private static function processObject(array $object)
1812         {
1813                 if (!JsonLD::fetchElement($object, '@id')) {
1814                         return false;
1815                 }
1816
1817                 $object_data = [];
1818                 $object_data['object_type'] = JsonLD::fetchElement($object, '@type');
1819                 $object_data['id'] = JsonLD::fetchElement($object, '@id');
1820                 $object_data['reply-to-id'] = JsonLD::fetchElement($object, 'as:inReplyTo', '@id');
1821
1822                 // An empty "id" field is translated to "./" by the compactor, so we have to check for this content
1823                 if (empty($object_data['reply-to-id']) || ($object_data['reply-to-id'] == './')) {
1824                         $object_data['reply-to-id'] = $object_data['id'];
1825
1826                         // On activities the "reply to" is the id of the object it refers to
1827                         if (in_array($object_data['object_type'], self::ACTIVITY_TYPES)) {
1828                                 $object_id = JsonLD::fetchElement($object, 'as:object', '@id');
1829                                 if (!empty($object_id)) {
1830                                         $object_data['reply-to-id'] = $object_id;
1831                                 }
1832                         }
1833                 } else {
1834                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
1835                         $replyToId = Item::getURIByLink($object_data['reply-to-id']);
1836                         if (!empty($replyToId) && ($object_data['reply-to-id'] != $replyToId)) {
1837                                 Logger::notice('Fix wrong reply-to', ['received' => $object_data['reply-to-id'], 'correct' => $replyToId]);
1838                                 $object_data['reply-to-id'] = $replyToId;
1839                         }
1840                 }
1841
1842                 $object_data['published'] = JsonLD::fetchElement($object, 'as:published', '@value');
1843                 $object_data['updated'] = JsonLD::fetchElement($object, 'as:updated', '@value');
1844
1845                 if (empty($object_data['updated'])) {
1846                         $object_data['updated'] = $object_data['published'];
1847                 }
1848
1849                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
1850                         $object_data['published'] = $object_data['updated'];
1851                 }
1852
1853                 $actor = JsonLD::fetchElement($object, 'as:attributedTo', '@id');
1854                 if (empty($actor)) {
1855                         $actor = JsonLD::fetchElement($object, 'as:actor', '@id');
1856                 }
1857
1858                 $location = JsonLD::fetchElement($object, 'as:location', 'as:name', '@type', 'as:Place');
1859                 $location = JsonLD::fetchElement($location, 'location', '@value');
1860                 if ($location) {
1861                         // Some AP software allow formatted text in post location, so we run all the text converters we have to boil
1862                         // down to HTML and then finally format to plaintext.
1863                         $location = Markdown::convert($location);
1864                         $location = BBCode::toPlaintext($location);
1865                 }
1866
1867                 $object_data['sc:identifier'] = JsonLD::fetchElement($object, 'sc:identifier', '@value');
1868                 $object_data['diaspora:guid'] = JsonLD::fetchElement($object, 'diaspora:guid', '@value');
1869                 $object_data['diaspora:comment'] = JsonLD::fetchElement($object, 'diaspora:comment', '@value');
1870                 $object_data['diaspora:like'] = JsonLD::fetchElement($object, 'diaspora:like', '@value');
1871                 $object_data['actor'] = $object_data['author'] = $actor;
1872                 $object_data['context'] = JsonLD::fetchElement($object, 'as:context', '@id');
1873                 $object_data['conversation'] = JsonLD::fetchElement($object, 'ostatus:conversation', '@id');
1874                 $object_data['sensitive'] = JsonLD::fetchElement($object, 'as:sensitive');
1875                 $object_data['name'] = JsonLD::fetchElement($object, 'as:name', '@value');
1876                 $object_data['summary'] = JsonLD::fetchElement($object, 'as:summary', '@value');
1877                 $object_data['content'] = JsonLD::fetchElement($object, 'as:content', '@value');
1878                 $object_data['mediatype'] = JsonLD::fetchElement($object, 'as:mediaType', '@value');
1879                 $object_data = self::getSource($object, $object_data);
1880                 $object_data['start-time'] = JsonLD::fetchElement($object, 'as:startTime', '@value');
1881                 $object_data['end-time'] = JsonLD::fetchElement($object, 'as:endTime', '@value');
1882                 $object_data['location'] = $location;
1883                 $object_data['latitude'] = JsonLD::fetchElement($object, 'as:location', 'as:latitude', '@type', 'as:Place');
1884                 $object_data['latitude'] = JsonLD::fetchElement($object_data, 'latitude', '@value');
1885                 $object_data['longitude'] = JsonLD::fetchElement($object, 'as:location', 'as:longitude', '@type', 'as:Place');
1886                 $object_data['longitude'] = JsonLD::fetchElement($object_data, 'longitude', '@value');
1887                 $object_data['attachments'] = self::processAttachments(JsonLD::fetchElementArray($object, 'as:attachment') ?? []);
1888                 $object_data['tags'] = self::processTags(JsonLD::fetchElementArray($object, 'as:tag') ?? []);
1889                 $object_data['emojis'] = self::processEmojis(JsonLD::fetchElementArray($object, 'as:tag', null, '@type', 'toot:Emoji') ?? []);
1890                 $object_data['languages'] = self::processLanguages(JsonLD::fetchElementArray($object, 'sc:inLanguage') ?? []);
1891                 $object_data['generator'] = JsonLD::fetchElement($object, 'as:generator', 'as:name', '@type', 'as:Application');
1892                 $object_data['generator'] = JsonLD::fetchElement($object_data, 'generator', '@value');
1893                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'as:url', '@id');
1894
1895                 // Special treatment for Hubzilla links
1896                 if (is_array($object_data['alternate-url'])) {
1897                         $object_data['alternate-url'] = JsonLD::fetchElement($object_data['alternate-url'], 'as:href', '@id');
1898
1899                         if (!is_string($object_data['alternate-url'])) {
1900                                 $object_data['alternate-url'] = JsonLD::fetchElement($object['as:url'], 'as:href', '@id');
1901                         }
1902                 }
1903
1904                 if (!empty($object_data['alternate-url']) && !Network::isValidHttpUrl($object_data['alternate-url'])) {
1905                         $object_data['alternate-url'] = null;
1906                 }
1907
1908                 if (in_array($object_data['object_type'], ['as:Audio', 'as:Video'])) {
1909                         $object_data['alternate-url'] = self::extractAlternateUrl($object['as:url'] ?? []) ?: $object_data['alternate-url'];
1910                         $object_data['attachments'] = array_merge($object_data['attachments'], self::processAttachmentUrls($object['as:url'] ?? []));
1911                 }
1912
1913                 // For page types we expect that the alternate url posts to some page.
1914                 // So we add this to the attachments if it differs from the id.
1915                 // Currently only Lemmy is using the page type.
1916                 if (($object_data['object_type'] == 'as:Page') && !empty($object_data['alternate-url']) && !Strings::compareLink($object_data['alternate-url'], $object_data['id'])) {
1917                         $object_data['attachments'][] = ['url' => $object_data['alternate-url']];
1918                         $object_data['alternate-url'] = null;
1919                 }
1920
1921                 if ($object_data['object_type'] == 'as:Question') {
1922                         $object_data['question'] = self::processQuestion($object);
1923                 }
1924
1925                 $receiverdata = self::getReceivers($object, $object_data['actor'] ?? '', $object_data['tags'], true);
1926                 $receivers = $reception_types = [];
1927                 foreach ($receiverdata as $key => $data) {
1928                         $receivers[$key] = $data['uid'];
1929                         $reception_types[$data['uid']] = $data['type'] ?? 0;
1930                 }
1931
1932                 $object_data['receiver_urls']  = self::getReceiverURL($object);
1933                 $object_data['receiver']       = $receivers;
1934                 $object_data['reception_type'] = $reception_types;
1935
1936                 $object_data['unlisted'] = in_array(-1, $object_data['receiver']);
1937                 unset($object_data['receiver'][-1]);
1938                 unset($object_data['reception_type'][-1]);
1939
1940                 return $object_data;
1941         }
1942
1943         /**
1944          * Add an object id to the list of arrived activities
1945          *
1946          * @param string $id
1947          *
1948          * @return void
1949          */
1950         private static function addArrivedId(string $id)
1951         {
1952                 DBA::delete('arrived-activity', ["`received` < ?", DateTimeFormat::utc('now - 5 minutes')]);
1953                 DBA::insert('arrived-activity', ['object-id' => $id, 'received' => DateTimeFormat::utcNow()], Database::INSERT_IGNORE);
1954         }
1955
1956         /**
1957          * Checks if the given object already arrived before
1958          *
1959          * @param string $id
1960          *
1961          * @return boolean
1962          */
1963         private static function hasArrived(string $id): bool
1964         {
1965                 return DBA::exists('arrived-activity', ['object-id' => $id]);
1966         }
1967 }