src/Protocol/ActivityPub/Receiver.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2010-2023, 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', 'as:View', 'as:Read', 'litepub:EmojiReact'];
  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         public 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' => [Item::GRAVITY_PARENT, Item::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                 $fetched = false;
 319
 320                 if (!empty($id) && !$trust_source) {
 321                         $fetch_uid = $uid ?: self::getBestUserForActivity($activity);
 322
 323                         $fetched_activity = Processor::fetchCachedActivity($fetch_id, $fetch_uid);
 324                         if (!empty($fetched_activity)) {
 325                                 $fetched = true;
 326                                 $object  = JsonLD::compact($fetched_activity);
 327
 328                                 $fetched_id   = JsonLD::fetchElement($object, '@id');
 329                                 $fetched_type = JsonLD::fetchElement($object, '@type');
 330
 331                                 if (($fetched_id == $id) && !empty($fetched_type) && ($fetched_type == $type)) {
 332                                         Logger::info('Activity had been fetched successfully', ['id' => $id]);
 333                                         $trust_source = true;
 334                                         $activity = $object;
 335                                 } elseif (($fetched_id == $object_id) && !empty($fetched_type) && ($fetched_type == $object_type)) {
 336                                         Logger::info('Fetched data is the object instead of the activity', ['id' => $id]);
 337                                         $trust_source = true;
 338                                         unset($object['@context']);
 339                                         $activity['as:object'] = $object;
 340                                 } else {
 341                                         Logger::info('Activity id is not equal', ['id' => $id, 'fetched' => $fetched_id]);
 342                                 }
 343                         } else {
 344                                 Logger::info('Activity could not been fetched', ['id' => $id]);
 345                         }
 346                 }
 347
 348                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 349                 if (empty($actor)) {
 350                         Logger::info('Empty actor', ['activity' => $activity]);
 351                         return [];
 352                 }
 353
 354                 $type = JsonLD::fetchElement($activity, '@type');
 355
 356                 // Fetch all receivers from to, cc, bto and bcc
 357                 $receiverdata = self::getReceivers($activity, $actor, [], false, $push || $fetched);
 358                 $receivers = $reception_types = [];
 359                 foreach ($receiverdata as $key => $data) {
 360                         $receivers[$key] = $data['uid'];
 361                         $reception_types[$data['uid']] = $data['type'] ?? self::TARGET_UNKNOWN;
 362                 }
 363
 364                 $urls = self::getReceiverURL($activity);
 365
 366                 // When it is a delivery to a personal inbox we add that user to the receivers
 367                 if (!empty($uid)) {
 368                         $additional = [$uid => $uid];
 369                         $receivers = array_replace($receivers, $additional);
 370                         if (empty($activity['thread-completion']) && (empty($reception_types[$uid]) || in_array($reception_types[$uid], [self::TARGET_UNKNOWN, self::TARGET_FOLLOWER, self::TARGET_ANSWER, self::TARGET_GLOBAL]))) {
 371                                 $reception_types[$uid] = self::TARGET_BCC;
 372                                 $owner = User::getOwnerDataById($uid);
 373                                 if (!empty($owner['url'])) {
 374                                         $urls['as:bcc'][] = $owner['url'];
 375                                 }
 376                         }
 377                 }
 378
 379                 // We possibly need some user to fetch private content,
 380                 // so we fetch one out of the receivers if no uid is provided.
 381                 $fetch_uid = $uid ?: self::getBestUserForActivity($activity);
 382
 383                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 384                 if (empty($object_id)) {
 385                         Logger::info('No object found');
 386                         return [];
 387                 }
 388
 389                 if (!is_string($object_id)) {
 390                         Logger::info('Invalid object id', ['object' => $object_id]);
 391                         return [];
 392                 }
 393
 394                 $object_type = self::fetchObjectType($activity, $object_id, $fetch_uid);
 395
 396                 // Fetch the activity on Lemmy "Announce" messages (announces of activities)
 397                 if (($type == 'as:Announce') && in_array($object_type, array_merge(self::ACTIVITY_TYPES, ['as:Delete', 'as:Undo', 'as:Update']))) {
 398                         Logger::debug('Fetch announced activity', ['object' => $object_id]);
 399                         $data = Processor::fetchCachedActivity($object_id, $fetch_uid);
 400                         if (!empty($data)) {
 401                                 $type = $object_type;
 402                                 $activity = JsonLD::compact($data);
 403
 404                                 // Some variables need to be refetched since the activity changed
 405                                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 406                                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 407                                 $object_type = self::fetchObjectType($activity, $object_id, $fetch_uid);
 408                         }
 409                 }
 410
 411                 // Any activities on account types must not be altered
 412                 if (in_array($type, ['as:Flag'])) {
 413                         $object_data = [];
 414                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 415                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 416                         $object_data['object_ids'] = JsonLD::fetchElementArray($activity, 'as:object', '@id');
 417                         $object_data['content'] = JsonLD::fetchElement($activity, 'as:content', '@type');
 418                 } elseif (in_array($object_type, self::ACCOUNT_TYPES)) {
 419                         $object_data = [];
 420                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 421                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 422                         $object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor', '@id');
 423                         $object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
 424                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 425                         if (!$trust_source && ($type == 'as:Delete')) {
 426                                 $apcontact = APContact::getByURL($object_data['object_id'], true);
 427                                 $trust_source = empty($apcontact) || ($apcontact['type'] == 'Tombstone') || $apcontact['suspended'];
 428                         }
 429                 } elseif (in_array($type, ['as:Create', 'as:Update', 'as:Invite']) || strpos($type, '#emojiReaction')) {
 430                         // Fetch the content only on activities where this matters
 431                         // We can receive "#emojiReaction" when fetching content from Hubzilla systems
 432                         $object_data = self::fetchObject($object_id, $activity['as:object'], $trust_source, $fetch_uid);
 433                         if (empty($object_data)) {
 434                                 Logger::info("Object data couldn't be processed");
 435                                 return [];
 436                         }
 437
 438                         $object_data['object_id'] = $object_id;
 439
 440                         // Test if it is an answer to a mail
 441                         if (DBA::exists('mail', ['uri' => $object_data['reply-to-id']])) {
 442                                 $object_data['directmessage'] = true;
 443                         } else {
 444                                 $object_data['directmessage'] = JsonLD::fetchElement($activity, 'litepub:directMessage');
 445                         }
 446                 } elseif (in_array($type, array_merge(self::ACTIVITY_TYPES, ['as:Announce', 'as:Follow'])) && in_array($object_type, self::CONTENT_TYPES)) {
 447                         // Create a mostly empty array out of the activity data (instead of the object).
 448                         // This way we later don't have to check for the existence of each individual array element.
 449                         $object_data = self::processObject($activity);
 450                         $object_data['name'] = $type;
 451                         $object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 452                         $object_data['object_id'] = $object_id;
 453                         $object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
 454                 } elseif (in_array($type, ['as:Add', 'as:Remove', 'as:Move'])) {
 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                 } else {
 462                         $object_data = [];
 463                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 464                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 465                         $object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor', '@id');
 466                         $object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
 467                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 468
 469                         // An Undo is done on the object of an object, so we need that type as well
 470                         if (($type == 'as:Undo') && !empty($object_data['object_object'])) {
 471                                 $object_data['object_object_type'] = self::fetchObjectType([], $object_data['object_object'], $fetch_uid);
 472                         }
 473
 474                         if (!$trust_source && ($type == 'as:Delete') && in_array($object_data['object_type'], array_merge(['as:Tombstone', ''], self::CONTENT_TYPES))) {
 475                                 $trust_source = Processor::isActivityGone($object_data['object_id']);
 476                                 if (!$trust_source) {
 477                                         $trust_source = !empty(APContact::getByURL($object_data['object_id'], false));
 478                                 }
 479                         }
 480                 }
 481
 482                 $object_data['push'] = $push;
 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                 $account = Contact::selectFirstAccount(['platform'], ['nurl' => Strings::normaliseLink($actor)]);
 516                 $platform = $account['platform'] ?? '';
 517
 518                 Logger::info('Processing', ['type' => $object_data['type'], 'object_type' => $object_data['object_type'], 'id' => $object_data['id'], 'actor' => $actor, 'platform' => $platform]);
 519
 520                 return $object_data;
 521         }
 522
 523         /**
 524          * Fetches the first user id from the receiver array
 525          *
 526          * @param array $receivers Array with receivers
 527          * @return integer user id;
 528          */
 529         public static function getFirstUserFromReceivers(array $receivers): int
 530         {
 531                 foreach ($receivers as $receiver) {
 532                         if (!empty($receiver)) {
 533                                 return $receiver;
 534                         }
 535                 }
 536                 return 0;
 537         }
 538
 539         /**
 540          * Processes the activity object
 541          *
 542          * @param array      $activity     Array with activity data
 543          * @param string     $body         The unprocessed body
 544          * @param int|null   $uid          User ID
 545          * @param boolean    $trust_source Do we trust the source?
 546          * @param boolean    $push         Message had been pushed to our system
 547          * @param array      $signer       The signer of the post
 548          *
 549          * @return bool
 550          *
 551          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 552          * @throws \ImagickException
 553          */
 554         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
 555         {
 556                 $type = JsonLD::fetchElement($activity, '@type');
 557                 if (!$type) {
 558                         Logger::info('Empty type', ['activity' => $activity]);
 559                         return true;
 560                 }
 561
 562                 if ($type == 'as:View') {
 563                         Logger::info('View activities are ignored.', ['signer' => $signer, 'http_signer' => $http_signer]);
 564                         return true;
 565                 }
 566
 567                 if (!JsonLD::fetchElement($activity, 'as:object', '@id')) {
 568                         Logger::info('Empty object', ['activity' => $activity]);
 569                         return true;
 570                 }
 571
 572                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 573                 if (empty($actor)) {
 574                         Logger::info('Empty actor', ['activity' => $activity]);
 575                         return true;
 576                 }
 577
 578                 if (is_array($activity['as:object'])) {
 579                         $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
 580                 } else {
 581                         $attributed_to = '';
 582                 }
 583
 584                 // Test the provided signatures against the actor and "attributedTo"
 585                 if ($trust_source) {
 586                         if (!empty($attributed_to) && !empty($actor)) {
 587                                 $trust_source = (in_array($actor, $signer) && in_array($attributed_to, $signer));
 588                         } else {
 589                                 $trust_source = in_array($actor, $signer);
 590                         }
 591                 }
 592
 593                 // $trust_source is called by reference and is set to true if the content was retrieved successfully
 594                 $object_data = self::prepareObjectData($activity, $uid, $push, $trust_source);
 595                 if (empty($object_data)) {
 596                         Logger::info('No object data found', ['activity' => $activity]);
 597                         return true;
 598                 }
 599
 600                 // Lemmy is announcing activities.
 601                 // We are changing the announces into regular activities.
 602                 if (($type == 'as:Announce') && in_array($object_data['type'] ?? '', array_merge(self::ACTIVITY_TYPES, ['as:Delete', 'as:Undo', 'as:Update']))) {
 603                         Logger::debug('Change type of announce to activity', ['type' => $object_data['type']]);
 604                         $type = $object_data['type'];
 605                 }
 606
 607                 if (!empty($body) && empty($object_data['raw'])) {
 608                         $object_data['raw'] = $body;
 609                 }
 610
 611                 // Internal flag for thread completion. See Processor.php
 612                 if (!empty($activity['thread-completion'])) {
 613                         $object_data['thread-completion'] = $activity['thread-completion'];
 614                 }
 615
 616                 if (!empty($activity['completion-mode'])) {
 617                         $object_data['completion-mode'] = $activity['completion-mode'];
 618                 }
 619
 620                 if (!empty($activity['thread-children-type'])) {
 621                         $object_data['thread-children-type'] = $activity['thread-children-type'];
 622                 }
 623
 624                 // Internal flag for posts that arrived via relay
 625                 if (!empty($activity['from-relay'])) {
 626                         $object_data['from-relay'] = $activity['from-relay'];
 627                 }
 628
 629                 if ($type == 'as:Announce') {
 630                         $object_data['object_activity'] = $activity;
 631                 }
 632
 633                 if (($type == 'as:Create') && $trust_source) {
 634                         if (self::hasArrived($object_data['object_id'])) {
 635                                 Logger::info('The activity already arrived.', ['id' => $object_data['object_id']]);
 636                                 return true;
 637                         }
 638                         self::addArrivedId($object_data['object_id']);
 639
 640                         if (Queue::exists($object_data['object_id'], $type)) {
 641                                 Logger::info('The activity is already added.', ['id' => $object_data['object_id']]);
 642                                 return true;
 643                         }
 644                 }
 645
 646                 $decouple = DI::config()->get('system', 'decoupled_receiver') && !in_array($completion, [self::COMPLETION_MANUAL, self::COMPLETION_ANNOUCE]);
 647
 648                 if ($decouple && ($trust_source || DI::config()->get('debug', 'ap_inbox_store_untrusted'))) {
 649                         $object_data = Queue::add($object_data, $type, $uid, $http_signer, $push, $trust_source);
 650                 }
 651
 652                 if (!$trust_source) {
 653                         Logger::info('Activity trust could not be achieved.',  ['id' => $object_data['object_id'], 'type' => $type, 'signer' => $signer, 'actor' => $actor, 'attributedTo' => $attributed_to]);
 654                         return true;
 655                 }
 656
 657                 if (!empty($object_data['entry-id']) && $decouple && ($push || ($completion == self::COMPLETION_RELAY))) {
 658                         if (Queue::isProcessable($object_data['entry-id'])) {
 659                                 // We delay by 5 seconds to allow to accumulate all receivers
 660                                 $delayed = date(DateTimeFormat::MYSQL, time() + 5);
 661                                 Logger::debug('Initiate processing', ['id' => $object_data['entry-id'], 'uri' => $object_data['object_id']]);
 662                                 $wid = Worker::add(['priority' => Worker::PRIORITY_HIGH, 'delayed' => $delayed], 'ProcessQueue', $object_data['entry-id']);
 663                                 Queue::setWorkerId($object_data['entry-id'], $wid);
 664                         } else {
 665                                 Logger::debug('Other queue entries need to be processed first.', ['id' => $object_data['entry-id']]);
 666                         }
 667                         return false;
 668                 }
 669
 670                 if (!empty($activity['recursion-depth'])) {
 671                         $object_data['recursion-depth'] = $activity['recursion-depth'];
 672                 }
 673
 674                 if (!self::routeActivities($object_data, $type, $push, true, $uid)) {
 675                         self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 676                         Queue::remove($object_data);
 677                 }
 678                 return true;
 679         }
 680
 681         /**
 682          * Route activities
 683          *
 684          * @param array  $object_data
 685          * @param string $type
 686          * @param bool   $push
 687          * @param bool   $fetch_parents
 688          * @param int    $uid
 689          *
 690          * @return boolean Could the activity be routed?
 691          */
 692         public static function routeActivities(array $object_data, string $type, bool $push, bool $fetch_parents = true, int $uid = 0): bool
 693         {
 694                 switch ($type) {
 695                         case 'as:Create':
 696                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 697                                         $item = ActivityPub\Processor::createItem($object_data, $fetch_parents);
 698                                         ActivityPub\Processor::postItem($object_data, $item);
 699                                 } elseif (in_array($object_data['object_type'], ['pt:CacheFile'])) {
 700                                         // Unhandled Peertube activity
 701                                         Queue::remove($object_data);
 702                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 703                                         ActivityPub\Processor::updatePerson($object_data);
 704                                 } else {
 705                                         return false;
 706                                 }
 707                                 break;
 708
 709                         case 'as:Invite':
 710                                 if (in_array($object_data['object_type'], ['as:Event'])) {
 711                                         $item = ActivityPub\Processor::createItem($object_data, $fetch_parents);
 712                                         ActivityPub\Processor::postItem($object_data, $item);
 713                                 } else {
 714                                         return false;
 715                                 }
 716                                 break;
 717
 718                         case 'as:Add':
 719                                 if ($object_data['object_type'] == 'as:tag') {
 720                                         ActivityPub\Processor::addTag($object_data);
 721                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 722                                         ActivityPub\Processor::addToFeaturedCollection($object_data);
 723                                 } elseif (in_array($object_data['object_type'], ['as:Tombstone', ''])) {
 724                                         // We don't have the object here or it is deleted. We ignore this activity.
 725                                         Queue::remove($object_data);
 726                                 } else {
 727                                         return false;
 728                                 }
 729                                 break;
 730
 731                         case 'as:Announce':
 732                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 733                                         if (!Item::searchByLink($object_data['object_id'], $uid)) {
 734                                                 if (ActivityPub\Processor::fetchMissingActivity($object_data['object_id'], [], $object_data['actor'], self::COMPLETION_ANNOUCE, $uid)) {
 735                                                         Logger::debug('Created announced id', ['uid' => $uid, 'id' => $object_data['object_id']]);
 736                                                         Queue::remove($object_data);
 737                                                 } else {
 738                                                         Logger::debug('Announced id was not created', ['uid' => $uid, 'id' => $object_data['object_id']]);
 739                                                         Queue::remove($object_data);
 740                                                         return true;
 741                                                 }
 742                                         } else {
 743                                                 Logger::info('Announced id already exists', ['uid' => $uid, 'id' => $object_data['object_id']]);
 744                                                 Queue::remove($object_data);
 745                                         }
 746
 747                                         ActivityPub\Processor::createActivity($object_data, Activity::ANNOUNCE);
 748                                 } elseif (in_array($object_data['object_type'], ['as:Tombstone', ''])) {
 749                                         // We don't have the object here or it is deleted. We ignore this activity.
 750                                         Queue::remove($object_data);
 751                                 } else {
 752                                         return false;
 753                                 }
 754                                 break;
 755
 756                         case 'as:Like':
 757                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 758                                         ActivityPub\Processor::createActivity($object_data, Activity::LIKE);
 759                                 } elseif (in_array($object_data['object_type'], ['as:Tombstone', ''])) {
 760                                         // We don't have the object here or it is deleted. We ignore this activity.
 761                                         Queue::remove($object_data);
 762                                 } else {
 763                                         return false;
 764                                 }
 765                                 break;
 766
 767                         case 'as:Dislike':
 768                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 769                                         ActivityPub\Processor::createActivity($object_data, Activity::DISLIKE);
 770                                 } elseif (in_array($object_data['object_type'], ['as:Tombstone', ''])) {
 771                                         // We don't have the object here or it is deleted. We ignore this activity.
 772                                         Queue::remove($object_data);
 773                                 } else {
 774                                         return false;
 775                                 }
 776                                 break;
 777
 778                         case 'as:TentativeAccept':
 779                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 780                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDMAYBE);
 781                                 } else {
 782                                         return false;
 783                                 }
 784                                 break;
 785
 786                         case 'as:Update':
 787                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 788                                         ActivityPub\Processor::updateItem($object_data);
 789                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 790                                         ActivityPub\Processor::updatePerson($object_data);
 791                                 } elseif (in_array($object_data['object_type'], ['pt:CacheFile'])) {
 792                                         // Unhandled Peertube activity
 793                                         Queue::remove($object_data);
 794                                 } else {
 795                                         return false;
 796                                 }
 797                                 break;
 798
 799                         case 'as:Delete':
 800                                 if (in_array($object_data['object_type'], array_merge(['as:Tombstone'], self::CONTENT_TYPES))) {
 801                                         ActivityPub\Processor::deleteItem($object_data);
 802                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 803                                         ActivityPub\Processor::deletePerson($object_data);
 804                                 } elseif ($object_data['object_type'] == '') {
 805                                         // The object type couldn't be determined. Most likely we don't have it here. We ignore this activity.
 806                                         Queue::remove($object_data);
 807                                 } else {
 808                                         return false;
 809                                 }
 810                                 break;
 811
 812                         case 'as:Move':
 813                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 814                                         ActivityPub\Processor::movePerson($object_data);
 815                                 } else {
 816                                         return false;
 817                                 }
 818                                 break;
 819
 820                         case 'as:Block':
 821                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 822                                         ActivityPub\Processor::blockAccount($object_data);
 823                                 } else {
 824                                         return false;
 825                                 }
 826                                 break;
 827
 828                         case 'as:Flag':
 829                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 830                                         ActivityPub\Processor::ReportAccount($object_data);
 831                                 } else {
 832                                         return false;
 833                                 }
 834                                 break;
 835
 836                         case 'as:Remove':
 837                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 838                                         ActivityPub\Processor::removeFromFeaturedCollection($object_data);
 839                                 } elseif (in_array($object_data['object_type'], ['as:Tombstone', ''])) {
 840                                         // We don't have the object here or it is deleted. We ignore this activity.
 841                                         Queue::remove($object_data);
 842                                 } else {
 843                                         return false;
 844                                 }
 845                                 break;
 846
 847                         case 'as:Follow':
 848                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 849                                         ActivityPub\Processor::followUser($object_data);
 850                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 851                                         $object_data['reply-to-id'] = $object_data['object_id'];
 852                                         ActivityPub\Processor::createActivity($object_data, Activity::FOLLOW);
 853                                 } else {
 854                                         return false;
 855                                 }
 856                                 break;
 857
 858                         case 'as:Accept':
 859                                 if ($object_data['object_type'] == 'as:Follow') {
 860                                         if (!empty($object_data['object_actor'])) {
 861                                                 ActivityPub\Processor::acceptFollowUser($object_data);
 862                                         } else {
 863                                                 Logger::notice('Unhandled "accept follow" message.', ['object_data' => $object_data]);
 864                                         }
 865                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 866                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTEND);
 867                                 } elseif (!empty($object_data['object_id']) && empty($object_data['object_actor']) && empty($object_data['object_type'])) {
 868                                         // Follow acceptances from gup.pe only contain the object id
 869                                         ActivityPub\Processor::acceptFollowUser($object_data);
 870                                 } else {
 871                                         return false;
 872                                 }
 873                                 break;
 874
 875                         case 'as:Reject':
 876                                 if ($object_data['object_type'] == 'as:Follow') {
 877                                         ActivityPub\Processor::rejectFollowUser($object_data);
 878                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 879                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDNO);
 880                                 } else {
 881                                         return false;
 882                                 }
 883                                 break;
 884
 885                         case 'as:Undo':
 886                                 if (($object_data['object_type'] == 'as:Follow') &&
 887                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 888                                         ActivityPub\Processor::undoFollowUser($object_data);
 889                                 } elseif (($object_data['object_type'] == 'as:Follow') &&
 890                                         in_array($object_data['object_object_type'], self::CONTENT_TYPES)) {
 891                                         ActivityPub\Processor::undoActivity($object_data);
 892                                 } elseif (($object_data['object_type'] == 'as:Accept') &&
 893                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 894                                         ActivityPub\Processor::rejectFollowUser($object_data);
 895                                 } elseif (($object_data['object_type'] == 'as:Block') &&
 896                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 897                                         ActivityPub\Processor::unblockAccount($object_data);
 898                                 } elseif (in_array($object_data['object_type'], array_merge(self::ACTIVITY_TYPES, ['as:Announce', 'as:Create', ''])) &&
 899                                         empty($object_data['object_object_type'])) {
 900                                         // We cannot detect the target object. So we can ignore it.
 901                                         Queue::remove($object_data);
 902                                 } elseif (in_array($object_data['object_type'], array_merge(self::ACTIVITY_TYPES, ['as:Announce'])) &&
 903                                         in_array($object_data['object_object_type'], array_merge(['as:Tombstone'], self::CONTENT_TYPES))) {
 904                                         ActivityPub\Processor::undoActivity($object_data);
 905                                 } elseif (in_array($object_data['object_type'], ['as:Create']) &&
 906                                         in_array($object_data['object_object_type'], ['pt:CacheFile'])) {
 907                                         // Unhandled Peertube activity
 908                                         Queue::remove($object_data);
 909                                 } elseif (in_array($object_data['object_type'], ['as:Delete'])) {
 910                                         // We cannot undo deletions, so we just ignore this
 911                                         Queue::remove($object_data);
 912                                 } elseif (in_array($object_data['object_object_type'], ['as:Tombstone'])) {
 913                                         // The object is a tombstone, we ignore any actions on it.
 914                                         Queue::remove($object_data);
 915                                 } else {
 916                                         return false;
 917                                 }
 918                                 break;
 919
 920                         case 'as:View':
 921                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 922                                         ActivityPub\Processor::createActivity($object_data, Activity::VIEW);
 923                                 } elseif (in_array($object_data['object_type'], ['as:Tombstone', ''])) {
 924                                         // We don't have the object here or it is deleted. We ignore this activity.
 925                                         Queue::remove($object_data);
 926                                 } else {
 927                                         return false;
 928                                 }
 929                                 break;
 930                         case 'as:Read':
 931                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 932                                         ActivityPub\Processor::createActivity($object_data, Activity::READ);
 933                                 } elseif (in_array($object_data['object_type'], ['as:Tombstone', ''])) {
 934                                         // We don't have the object here or it is deleted. We ignore this activity.
 935                                         Queue::remove($object_data);
 936                                 } else {
 937                                         return false;
 938                                 }
 939                                 break;
 940
 941                         case 'litepub:EmojiReact':
 942                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 943                                         ActivityPub\Processor::createActivity($object_data, Activity::EMOJIREACT);
 944                                 } elseif (in_array($object_data['object_type'], ['as:Tombstone', ''])) {
 945                                         // We don't have the object here or it is deleted. We ignore this activity.
 946                                         Queue::remove($object_data);
 947                                 } else {
 948                                         return false;
 949                                 }
 950                                 break;
 951
 952                         default:
 953                                 Logger::info('Unknown activity: ' . $type . ' ' . $object_data['object_type']);
 954                                 return false;
 955                 }
 956                 return true;
 957         }
 958
 959         /**
 960          * Stores unhandled or unknown Activities as a file
 961          *
 962          * @param boolean $unknown      "true" if the activity is unknown, "false" if it is unhandled
 963          * @param string  $type         Activity type
 964          * @param array   $object_data  Preprocessed array that is generated out of the received activity
 965          * @param array   $activity     Array with activity data
 966          * @param string  $body         The unprocessed body
 967          * @param integer $uid          User ID
 968          * @param boolean $trust_source Do we trust the source?
 969          * @param boolean $push         Message had been pushed to our system
 970          * @param array   $signer       The signer of the post
 971          * @return void
 972          */
 973         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 = [])
 974         {
 975                 if (!DI::config()->get('debug', 'ap_log_unknown')) {
 976                         return;
 977                 }
 978
 979                 $file = ($unknown  ? 'unknown-' : 'unhandled-') . str_replace(':', '-', $type) . '-';
 980
 981                 if (!empty($object_data['object_type'])) {
 982                         $file .= str_replace(':', '-', $object_data['object_type']) . '-';
 983                 }
 984
 985                 if (!empty($object_data['object_object_type'])) {
 986                         $file .= str_replace(':', '-', $object_data['object_object_type']) . '-';
 987                 }
 988
 989                 $tempfile = tempnam(System::getTempPath(), $file);
 990                 file_put_contents($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));
 991                 Logger::notice('Unknown activity stored', ['type' => $type, 'object_type' => $object_data['object_type'], 'object_object_type' => $object_data['object_object_type'] ?? '', 'file' => $tempfile]);
 992         }
 993
 994         /**
 995          * Fetch a user id from an activity array
 996          *
 997          * @param array  $activity
 998          * @param string $actor
 999          *
1000          * @return int   user id
1001          */
1002         public static function getBestUserForActivity(array $activity): int
1003         {
1004                 $uid = 0;
1005                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id') ?? '';
1006
1007                 $receivers = self::getReceivers($activity, $actor, [], false, false);
1008                 foreach ($receivers as $receiver) {
1009                         if ($receiver['type'] == self::TARGET_GLOBAL) {
1010                                 return 0;
1011                         }
1012                         if (empty($uid) || ($receiver['type'] == self::TARGET_TO)) {
1013                                 $uid = $receiver['uid'];
1014                         }
1015                 }
1016
1017                 // When we haven't found any user yet, we just chose a user who most likely could have access to the content
1018                 if (empty($uid)) {
1019                         $contact = Contact::selectFirst(['uid'], ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND]]);
1020                         if (!empty($contact['uid'])) {
1021                                 $uid = $contact['uid'];
1022                         }
1023                 }
1024
1025                 return $uid;
1026         }
1027
1028         // @TODO Missing documentation
1029         public static function getReceiverURL(array $activity): array
1030         {
1031                 $urls = [];
1032
1033                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
1034                         $receiver_list = JsonLD::fetchElementArray($activity, $element, '@id');
1035                         if (empty($receiver_list)) {
1036                                 continue;
1037                         }
1038
1039                         foreach ($receiver_list as $receiver) {
1040                                 if ($receiver == 'Public') {
1041                                         Logger::warning('Not compacted public collection found', ['activity' => $activity, 'callstack' => System::callstack(20)]);
1042                                         $receiver = ActivityPub::PUBLIC_COLLECTION;
1043                                 }
1044                                 if ($receiver == self::PUBLIC_COLLECTION) {
1045                                         $receiver = ActivityPub::PUBLIC_COLLECTION;
1046                                 }
1047                                 $urls[$element][] = $receiver;
1048                         }
1049                 }
1050
1051                 return $urls;
1052         }
1053
1054         /**
1055          * Fetch the receiver list from an activity array
1056          *
1057          * @param array   $activity
1058          * @param string $actor
1059          * @param array  $tags
1060          * @param bool   $fetch_unlisted
1061          * @param bool   $push
1062          *
1063          * @return array with receivers (user id)
1064          * @throws \Exception
1065          */
1066         private static function getReceivers(array $activity, string $actor, array $tags, bool $fetch_unlisted, bool $push): array
1067         {
1068                 $reply = $receivers = $profile = [];
1069
1070                 // When it is an answer, we inherite the receivers from the parent
1071                 $replyto = JsonLD::fetchElement($activity, 'as:inReplyTo', '@id');
1072                 if (!empty($replyto)) {
1073                         $reply = [$replyto];
1074
1075                         // Fix possibly wrong item URI (could be an answer to a plink uri)
1076                         $fixedReplyTo = Item::getURIByLink($replyto);
1077                         if (!empty($fixedReplyTo)) {
1078                                 $reply[] = $fixedReplyTo;
1079                         }
1080                 }
1081
1082                 // Fetch all posts that refer to the object id
1083                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
1084                 if (!empty($object_id)) {
1085                         $reply[] = $object_id;
1086                 }
1087
1088                 if (!empty($reply)) {
1089                         $parents = Post::select(['uid'], DBA::mergeConditions(['uri' => $reply], ["`uid` != ?", 0]));
1090                         while ($parent = Post::fetch($parents)) {
1091                                 $receivers[$parent['uid']] = ['uid' => $parent['uid'], 'type' => self::TARGET_ANSWER];
1092                         }
1093                         DBA::close($parents);
1094                 }
1095
1096                 if (!empty($actor)) {
1097                         $profile   = APContact::getByURL($actor);
1098                         $followers = $profile['followers'] ?? '';
1099                         $is_forum  = ($actor['type'] ?? '') == 'Group';
1100                         if ($push) {
1101                                 Contact::updateByUrlIfNeeded($actor);
1102                         }
1103                         Logger::info('Got actor and followers', ['actor' => $actor, 'followers' => $followers]);
1104                 } else {
1105                         Logger::info('Empty actor', ['activity' => $activity]);
1106                         $followers = '';
1107                         $is_forum  = false;
1108                 }
1109
1110                 // We have to prevent false follower assumptions upon thread completions
1111                 $follower_target = empty($activity['thread-completion']) ? self::TARGET_FOLLOWER : self::TARGET_UNKNOWN;
1112
1113                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
1114                         $receiver_list = JsonLD::fetchElementArray($activity, $element, '@id');
1115                         if (empty($receiver_list)) {
1116                                 continue;
1117                         }
1118
1119                         foreach ($receiver_list as $receiver) {
1120                                 if ($receiver == self::PUBLIC_COLLECTION) {
1121                                         $receivers[0] = ['uid' => 0, 'type' => self::TARGET_GLOBAL];
1122                                 }
1123
1124                                 // Add receiver "-1" for unlisted posts
1125                                 if ($fetch_unlisted && ($receiver == self::PUBLIC_COLLECTION) && ($element == 'as:cc')) {
1126                                         $receivers[-1] = ['uid' => -1, 'type' => self::TARGET_GLOBAL];
1127                                 }
1128
1129                                 // Fetch the receivers for the public and the followers collection
1130                                 if ((($receiver == $followers) || (($receiver == self::PUBLIC_COLLECTION) && !$is_forum)) && !empty($actor)) {
1131                                         $receivers = self::getReceiverForActor($actor, $tags, $receivers, $follower_target, $profile);
1132                                         continue;
1133                                 }
1134
1135                                 // Fetching all directly addressed receivers
1136                                 $condition = ['self' => true, 'nurl' => Strings::normaliseLink($receiver)];
1137                                 $contact = DBA::selectFirst('contact', ['uid', 'contact-type'], $condition);
1138                                 if (!DBA::isResult($contact)) {
1139                                         continue;
1140                                 }
1141
1142                                 // Check if the potential receiver is following the actor
1143                                 // Exception: The receiver is targetted via "to" or this is a comment
1144                                 if ((($element != 'as:to') && empty($replyto)) || ($contact['contact-type'] == Contact::TYPE_COMMUNITY)) {
1145                                         $networks = Protocol::FEDERATED;
1146                                         $condition = ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
1147                                                 'network' => $networks, 'archive' => false, 'pending' => false, 'uid' => $contact['uid']];
1148
1149                                         // Forum posts are only accepted from forum contacts
1150                                         if ($contact['contact-type'] == Contact::TYPE_COMMUNITY) {
1151                                                 $condition['rel'] = [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER];
1152                                         }
1153
1154                                         if (!DBA::exists('contact', $condition)) {
1155                                                 continue;
1156                                         }
1157                                 }
1158
1159                                 $type = $receivers[$contact['uid']]['type'] ?? self::TARGET_UNKNOWN;
1160                                 if (in_array($type, [self::TARGET_UNKNOWN, self::TARGET_FOLLOWER, self::TARGET_ANSWER, self::TARGET_GLOBAL])) {
1161                                         switch ($element) {
1162                                                 case 'as:to':
1163                                                         $type = self::TARGET_TO;
1164                                                         break;
1165                                                 case 'as:cc':
1166                                                         $type = self::TARGET_CC;
1167                                                         break;
1168                                                 case 'as:bto':
1169                                                         $type = self::TARGET_BTO;
1170                                                         break;
1171                                                 case 'as:bcc':
1172                                                         $type = self::TARGET_BCC;
1173                                                         break;
1174                                         }
1175
1176                                         $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $type];
1177                                 }
1178                         }
1179                 }
1180
1181                 self::switchContacts($receivers, $actor);
1182
1183                 // "birdsitelive" is a service that mirrors tweets into the fediverse
1184                 // These posts can be fetched without authentification, but are not marked as public
1185                 // We treat them as unlisted posts to be able to handle them.
1186                 if (empty($receivers) && $fetch_unlisted && Contact::isPlatform($actor, 'birdsitelive')) {
1187                         $receivers[0]  = ['uid' => 0, 'type' => self::TARGET_GLOBAL];
1188                         $receivers[-1] = ['uid' => -1, 'type' => self::TARGET_GLOBAL];
1189                         Logger::notice('Post from "birdsitelive" is set to "unlisted"', ['id' => JsonLD::fetchElement($activity, '@id')]);
1190                 } elseif (empty($receivers)) {
1191                         Logger::notice('Post has got no receivers', ['fetch_unlisted' => $fetch_unlisted, 'actor' => $actor, 'id' => JsonLD::fetchElement($activity, '@id'), 'type' => JsonLD::fetchElement($activity, '@type')]);
1192                 }
1193
1194                 return $receivers;
1195         }
1196
1197         /**
1198          * Fetch the receiver list of a given actor
1199          *
1200          * @param string  $actor
1201          * @param array   $tags
1202          * @param array   $receivers
1203          * @param integer $target_type
1204          * @param array   $profile
1205          *
1206          * @return array with receivers (user id)
1207          * @throws \Exception
1208          */
1209         private static function getReceiverForActor(string $actor, array $tags, array $receivers, int $target_type, array $profile): array
1210         {
1211                 $basecondition = ['rel' => [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER],
1212                         'network' => Protocol::FEDERATED, 'archive' => false, 'pending' => false];
1213
1214                 if (!empty($profile['uri-id'])) {
1215                         $condition = DBA::mergeConditions($basecondition, ["`uri-id` = ? AND `uid` != ?", $profile['uri-id'], 0]);
1216                         $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
1217                         while ($contact = DBA::fetch($contacts)) {
1218                                 if (empty($receivers[$contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
1219                                         $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $target_type];
1220                                 }
1221                         }
1222                         DBA::close($contacts);
1223                 } else {
1224                         // This part will only be called while post update 1426 wasn't finished
1225                         $condition = DBA::mergeConditions($basecondition, ["`nurl` = ? AND `uid` != ?", Strings::normaliseLink($actor), 0]);
1226                         $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
1227                         while ($contact = DBA::fetch($contacts)) {
1228                                 if (empty($receivers[$contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
1229                                         $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $target_type];
1230                                 }
1231                         }
1232                         DBA::close($contacts);
1233
1234                         // The queries are split because of performance issues
1235                         $condition = DBA::mergeConditions($basecondition, ["`alias` IN (?, ?) AND `uid` != ?", Strings::normaliseLink($actor), $actor, 0]);
1236                         $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
1237                         while ($contact = DBA::fetch($contacts)) {
1238                                 if (empty($receivers[$contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
1239                                         $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $target_type];
1240                                 }
1241                         }
1242                         DBA::close($contacts);
1243                 }
1244                 return $receivers;
1245         }
1246
1247         /**
1248          * Tests if the contact is a valid receiver for this actor
1249          *
1250          * @param array  $contact
1251          * @param array  $tags
1252          *
1253          * @return bool with receivers (user id)
1254          * @throws \Exception
1255          */
1256         private static function isValidReceiverForActor(array $contact, array $tags): bool
1257         {
1258                 // Are we following the contact? Then this is a valid receiver
1259                 if (in_array($contact['rel'], [Contact::SHARING, Contact::FRIEND])) {
1260                         return true;
1261                 }
1262
1263                 // When the possible receiver isn't a community, then it is no valid receiver
1264                 $owner = User::getOwnerDataById($contact['uid']);
1265                 if (empty($owner) || ($owner['contact-type'] != Contact::TYPE_COMMUNITY)) {
1266                         return false;
1267                 }
1268
1269                 // Is the community account tagged?
1270                 foreach ($tags as $tag) {
1271                         if ($tag['type'] != 'Mention') {
1272                                 continue;
1273                         }
1274
1275                         if (Strings::compareLink($tag['href'], $owner['url'])) {
1276                                 return true;
1277                         }
1278                 }
1279
1280                 return false;
1281         }
1282
1283         /**
1284          * Switches existing contacts to ActivityPub
1285          *
1286          * @param integer $cid Contact ID
1287          * @param integer $uid User ID
1288          * @param string  $url Profile URL
1289          * @return void
1290          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1291          * @throws \ImagickException
1292          */
1293         public static function switchContact(int $cid, int $uid, string $url)
1294         {
1295                 if (DBA::exists('contact', ['id' => $cid, 'network' => Protocol::ACTIVITYPUB])) {
1296                         Logger::info('Contact is already ActivityPub', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
1297                         return;
1298                 }
1299
1300                 if (Contact::updateFromProbe($cid)) {
1301                         Logger::info('Update was successful', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
1302                 }
1303
1304                 // Send a new follow request to be sure that the connection still exists
1305                 if (($uid != 0) && DBA::exists('contact', ['id' => $cid, 'rel' => [Contact::SHARING, Contact::FRIEND], 'network' => Protocol::ACTIVITYPUB])) {
1306                         Logger::info('Contact had been switched to ActivityPub. Sending a new follow request.', ['uid' => $uid, 'url' => $url]);
1307                         ActivityPub\Transmitter::sendActivity('Follow', $url, $uid);
1308                 }
1309         }
1310
1311         /**
1312          * @TODO Fix documentation and type-hints
1313          *
1314          * @param $receivers
1315          * @param $actor
1316          * @return void
1317          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1318          * @throws \ImagickException
1319          */
1320         private static function switchContacts($receivers, $actor)
1321         {
1322                 if (empty($actor)) {
1323                         return;
1324                 }
1325
1326                 foreach ($receivers as $receiver) {
1327                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver['uid'], 'network' => Protocol::OSTATUS, 'nurl' => Strings::normaliseLink($actor)]);
1328                         if (DBA::isResult($contact)) {
1329                                 self::switchContact($contact['id'], $receiver['uid'], $actor);
1330                         }
1331
1332                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver['uid'], 'network' => Protocol::OSTATUS, 'alias' => [Strings::normaliseLink($actor), $actor]]);
1333                         if (DBA::isResult($contact)) {
1334                                 self::switchContact($contact['id'], $receiver['uid'], $actor);
1335                         }
1336                 }
1337         }
1338
1339         /**
1340          * @TODO Fix documentation and type-hints
1341          *
1342          * @param       $object_data
1343          * @param array $activity
1344          *
1345          * @return mixed
1346          */
1347         private static function addActivityFields($object_data, array $activity)
1348         {
1349                 if (!empty($activity['published']) && empty($object_data['published'])) {
1350                         $object_data['published'] = JsonLD::fetchElement($activity, 'as:published', '@value');
1351                 }
1352
1353                 if (!empty($activity['diaspora:guid']) && empty($object_data['diaspora:guid'])) {
1354                         $object_data['diaspora:guid'] = JsonLD::fetchElement($activity, 'diaspora:guid', '@value');
1355                 }
1356
1357                 $object_data['service'] = JsonLD::fetchElement($activity, 'as:instrument', 'as:name', '@type', 'as:Service');
1358                 $object_data['service'] = JsonLD::fetchElement($object_data, 'service', '@value');
1359
1360                 if (!empty($object_data['object_id'])) {
1361                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
1362                         $objectId = Item::getURIByLink($object_data['object_id']);
1363                         if (!empty($objectId) && ($object_data['object_id'] != $objectId)) {
1364                                 Logger::notice('Fix wrong object-id', ['received' => $object_data['object_id'], 'correct' => $objectId]);
1365                                 $object_data['object_id'] = $objectId;
1366                         }
1367                 }
1368
1369                 return $object_data;
1370         }
1371
1372         /**
1373          * Fetches the object data from external ressources if needed
1374          *
1375          * @param string  $object_id    Object ID of the the provided object
1376          * @param array   $object       The provided object array
1377          * @param boolean $trust_source Do we trust the provided object?
1378          * @param integer $uid          User ID for the signature that we use to fetch data
1379          *
1380          * @return array|false with trusted and valid object data
1381          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1382          * @throws \ImagickException
1383          */
1384         private static function fetchObject(string $object_id, array $object = [], bool $trust_source = false, int $uid = 0)
1385         {
1386                 // By fetching the type we check if the object is complete.
1387                 $type = JsonLD::fetchElement($object, '@type');
1388
1389                 if (!$trust_source || empty($type)) {
1390                         $data = Processor::fetchCachedActivity($object_id, $uid);
1391                         if (!empty($data)) {
1392                                 $object = JsonLD::compact($data);
1393                                 Logger::info('Fetched content for ' . $object_id);
1394                         } else {
1395                                 Logger::info('Empty content for ' . $object_id . ', check if content is available locally.');
1396
1397                                 $item = Post::selectFirst(Item::DELIVER_FIELDLIST, ['uri' => $object_id]);
1398                                 if (!DBA::isResult($item)) {
1399                                         Logger::info('Object with url ' . $object_id . ' was not found locally.');
1400                                         return false;
1401                                 }
1402                                 Logger::info('Using already stored item for url ' . $object_id);
1403                                 $data = ActivityPub\Transmitter::createNote($item);
1404                                 $object = JsonLD::compact($data);
1405                         }
1406
1407                         $id = JsonLD::fetchElement($object, '@id');
1408                         if (empty($id)) {
1409                                 Logger::info('Empty id');
1410                                 return false;
1411                         }
1412
1413                         if ($id != $object_id) {
1414                                 Logger::info('Fetched id differs from provided id', ['provided' => $object_id, 'fetched' => $id]);
1415                                 return false;
1416                         }
1417                 } else {
1418                         Logger::info('Using original object for url ' . $object_id);
1419                 }
1420
1421                 $type = JsonLD::fetchElement($object, '@type');
1422                 if (empty($type)) {
1423                         Logger::info('Empty type');
1424                         return false;
1425                 }
1426
1427                 // Lemmy is resharing "create" activities instead of content
1428                 // We fetch the content from the activity.
1429                 if (in_array($type, ['as:Create'])) {
1430                         $object = $object['as:object'];
1431                         $type = JsonLD::fetchElement($object, '@type');
1432                         if (empty($type)) {
1433                                 Logger::info('Empty type');
1434                                 return false;
1435                         }
1436                         $object_data = self::processObject($object);
1437                 }
1438
1439                 // We currently don't handle 'pt:CacheFile', but with this step we avoid logging
1440                 if (in_array($type, self::CONTENT_TYPES) || ($type == 'pt:CacheFile')) {
1441                         $object_data = self::processObject($object);
1442
1443                         if (!empty($data)) {
1444                                 $object_data['raw-object'] = json_encode($data);
1445                         }
1446                         return $object_data;
1447                 }
1448
1449                 Logger::info('Unhandled object type: ' . $type);
1450                 return false;
1451         }
1452
1453         /**
1454          * Converts the language element (Used by Peertube)
1455          *
1456          * @param array $languages
1457          * @return array Languages
1458          */
1459         public static function processLanguages(array $languages): array
1460         {
1461                 if (empty($languages)) {
1462                         return [];
1463                 }
1464
1465                 $language_list = [];
1466
1467                 foreach ($languages as $language) {
1468                         if (!empty($language['_:identifier']) && !empty($language['as:name'])) {
1469                                 $language_list[$language['_:identifier']] = $language['as:name'];
1470                         }
1471                 }
1472                 return $language_list;
1473         }
1474
1475         /**
1476          * Convert tags from JSON-LD format into a simplified format
1477          *
1478          * @param array $tags Tags in JSON-LD format
1479          *
1480          * @return array with tags in a simplified format
1481          */
1482         public static function processTags(array $tags): array
1483         {
1484                 $taglist = [];
1485
1486                 foreach ($tags as $tag) {
1487                         if (empty($tag)) {
1488                                 continue;
1489                         }
1490
1491                         $element = ['type' => str_replace('as:', '', JsonLD::fetchElement($tag, '@type') ?? ''),
1492                                 'href' => JsonLD::fetchElement($tag, 'as:href', '@id'),
1493                                 'name' => JsonLD::fetchElement($tag, 'as:name', '@value')];
1494
1495                         if (empty($element['type'])) {
1496                                 continue;
1497                         }
1498
1499                         if (empty($element['href'])) {
1500                                 $element['href'] = $element['name'];
1501                         }
1502
1503                         $taglist[] = $element;
1504                 }
1505                 return $taglist;
1506         }
1507
1508         /**
1509          * Convert emojis from JSON-LD format into a simplified format
1510          *
1511          * @param array $emojis
1512          * @return array with emojis in a simplified format
1513          */
1514         private static function processEmojis(array $emojis): array
1515         {
1516                 $emojilist = [];
1517
1518                 foreach ($emojis as $emoji) {
1519                         if (empty($emoji) || (JsonLD::fetchElement($emoji, '@type') != 'toot:Emoji') || empty($emoji['as:icon'])) {
1520                                 continue;
1521                         }
1522
1523                         $url = JsonLD::fetchElement($emoji['as:icon'], 'as:url', '@id');
1524                         $element = ['name' => JsonLD::fetchElement($emoji, 'as:name', '@value'),
1525                                 'href' => $url];
1526
1527                         $emojilist[] = $element;
1528                 }
1529
1530                 return $emojilist;
1531         }
1532
1533         /**
1534          * Convert attachments from JSON-LD format into a simplified format
1535          *
1536          * @param array $attachments Attachments in JSON-LD format
1537          *
1538          * @return array Attachments in a simplified format
1539          */
1540         private static function processAttachments(array $attachments): array
1541         {
1542                 $attachlist = [];
1543
1544                 // Removes empty values
1545                 $attachments = array_filter($attachments);
1546
1547                 foreach ($attachments as $attachment) {
1548                         switch (JsonLD::fetchElement($attachment, '@type')) {
1549                                 case 'as:Page':
1550                                         $pageUrl = null;
1551                                         $pageImage = null;
1552
1553                                         $urls = JsonLD::fetchElementArray($attachment, 'as:url');
1554                                         foreach ($urls as $url) {
1555                                                 // Single scalar URL case
1556                                                 if (is_string($url)) {
1557                                                         $pageUrl = $url;
1558                                                         continue;
1559                                                 }
1560
1561                                                 $href = JsonLD::fetchElement($url, 'as:href', '@id');
1562                                                 $mediaType = JsonLD::fetchElement($url, 'as:mediaType', '@value');
1563                                                 if (Strings::startsWith($mediaType, 'image')) {
1564                                                         $pageImage = $href;
1565                                                 } else {
1566                                                         $pageUrl = $href;
1567                                                 }
1568                                         }
1569
1570                                         $attachlist[] = [
1571                                                 'type'  => 'link',
1572                                                 'title' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1573                                                 'desc'  => JsonLD::fetchElement($attachment, 'as:summary', '@value'),
1574                                                 'url'   => $pageUrl,
1575                                                 'image' => $pageImage,
1576                                         ];
1577                                         break;
1578                                 case 'as:Image':
1579                                         $mediaType = JsonLD::fetchElement($attachment, 'as:mediaType', '@value');
1580                                         $imageFullUrl = JsonLD::fetchElement($attachment, 'as:url', '@id');
1581                                         $imagePreviewUrl = null;
1582                                         // Multiple URLs?
1583                                         if (!$imageFullUrl && ($urls = JsonLD::fetchElementArray($attachment, 'as:url'))) {
1584                                                 $imageVariants = [];
1585                                                 $previewVariants = [];
1586                                                 foreach ($urls as $url) {
1587                                                         // Scalar URL, no discrimination possible
1588                                                         if (is_string($url)) {
1589                                                                 $imageFullUrl = $url;
1590                                                                 continue;
1591                                                         }
1592
1593                                                         // Not sure what to do with a different Link media type than the base Image, we skip
1594                                                         if ($mediaType != JsonLD::fetchElement($url, 'as:mediaType', '@value')) {
1595                                                                 continue;
1596                                                         }
1597
1598                                                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1599
1600                                                         // Default URL choice if no discriminating width is provided
1601                                                         $imageFullUrl = $href ?? $imageFullUrl;
1602
1603                                                         $width = intval(JsonLD::fetchElement($url, 'as:width', '@value') ?? 1);
1604
1605                                                         if ($href && $width) {
1606                                                                 $imageVariants[$width] = $href;
1607                                                                 // 632 is the ideal width for full screen frio posts, we compute the absolute distance to it
1608                                                                 $previewVariants[abs(632 - $width)] = $href;
1609                                                         }
1610                                                 }
1611
1612                                                 if ($imageVariants) {
1613                                                         // Taking the maximum size image
1614                                                         ksort($imageVariants);
1615                                                         $imageFullUrl = array_pop($imageVariants);
1616
1617                                                         // Taking the minimum number distance to the target distance
1618                                                         ksort($previewVariants);
1619                                                         $imagePreviewUrl = array_shift($previewVariants);
1620                                                 }
1621
1622                                                 unset($imageVariants);
1623                                                 unset($previewVariants);
1624                                         }
1625
1626                                         $attachlist[] = [
1627                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1628                                                 'mediaType' => $mediaType,
1629                                                 'name'  => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1630                                                 'url'   => $imageFullUrl,
1631                                                 'image' => $imagePreviewUrl !== $imageFullUrl ? $imagePreviewUrl : null,
1632                                         ];
1633                                         break;
1634                                 default:
1635                                         $attachlist[] = [
1636                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1637                                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType', '@value'),
1638                                                 'name' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1639                                                 'url' => JsonLD::fetchElement($attachment, 'as:url', '@id'),
1640                                                 'height' => JsonLD::fetchElement($attachment, 'as:height', '@value'),
1641                                                 'width' => JsonLD::fetchElement($attachment, 'as:width', '@value'),
1642                                                 'image' => JsonLD::fetchElement($attachment, 'as:image', '@id')
1643                                         ];
1644                         }
1645                 }
1646
1647                 return $attachlist;
1648         }
1649
1650         /**
1651          * Convert questions from JSON-LD format into a simplified format
1652          *
1653          * @param array $object
1654          *
1655          * @return array Questions in a simplified format
1656          */
1657         private static function processQuestion(array $object): array
1658         {
1659                 $question = [];
1660
1661                 if (!empty($object['as:oneOf'])) {
1662                         $question['multiple'] = false;
1663                         $options = JsonLD::fetchElementArray($object, 'as:oneOf') ?? [];
1664                 } elseif (!empty($object['as:anyOf'])) {
1665                         $question['multiple'] = true;
1666                         $options = JsonLD::fetchElementArray($object, 'as:anyOf') ?? [];
1667                 } else {
1668                         return [];
1669                 }
1670
1671                 $closed = JsonLD::fetchElement($object, 'as:closed', '@value');
1672                 if (!empty($closed)) {
1673                         $question['end-time'] = $closed;
1674                 } else {
1675                         $question['end-time'] = JsonLD::fetchElement($object, 'as:endTime', '@value');
1676                 }
1677
1678                 $question['voters']  = (int)JsonLD::fetchElement($object, 'toot:votersCount', '@value');
1679                 $question['options'] = [];
1680
1681                 $voters = 0;
1682
1683                 foreach ($options as $option) {
1684                         if (JsonLD::fetchElement($option, '@type') != 'as:Note') {
1685                                 continue;
1686                         }
1687
1688                         $name = JsonLD::fetchElement($option, 'as:name', '@value');
1689
1690                         if (empty($option['as:replies'])) {
1691                                 continue;
1692                         }
1693
1694                         $replies = JsonLD::fetchElement($option['as:replies'], 'as:totalItems', '@value');
1695
1696                         $question['options'][] = ['name' => $name, 'replies' => $replies];
1697
1698                         $voters += (int)$replies;
1699                 }
1700
1701                 // For single choice question we can count the number of voters if not provided (like with Misskey)
1702                 if (empty($question['voters']) && !$question['multiple']) {
1703                         $question['voters'] = $voters;
1704                 }
1705
1706                 return $question;
1707         }
1708
1709         /**
1710          * Fetch the original source or content with the "language" Markdown or HTML
1711          *
1712          * @param array $object
1713          * @param array $object_data
1714          *
1715          * @return array Object data (?)
1716          * @throws \Exception
1717          */
1718         private static function getSource(array $object, array $object_data): array
1719         {
1720                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/bbcode');
1721                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1722                 if (!empty($object_data['source'])) {
1723                         return $object_data;
1724                 }
1725
1726                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/markdown');
1727                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1728                 if (!empty($object_data['source'])) {
1729                         $object_data['source'] = Markdown::toBBCode($object_data['source']);
1730                         return $object_data;
1731                 }
1732
1733                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/html');
1734                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1735                 if (!empty($object_data['source'])) {
1736                         $object_data['source'] = HTML::toBBCode($object_data['source']);
1737                         return $object_data;
1738                 }
1739
1740                 return $object_data;
1741         }
1742
1743         /**
1744          * Extracts a potential alternate URL from a list of additional URL elements
1745          *
1746          * @param array $urls
1747          * @return string
1748          */
1749         private static function extractAlternateUrl(array $urls): string
1750         {
1751                 $alternateUrl = '';
1752                 foreach ($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($mediatype)) {
1769                                 continue;
1770                         }
1771
1772                         if ($mediatype == 'text/html') {
1773                                 $alternateUrl = $href;
1774                         }
1775                 }
1776
1777                 return $alternateUrl;
1778         }
1779
1780         /**
1781          * Check if the "as:url" element is an array with multiple links
1782          * This is the case with audio and video posts.
1783          * Then the links are added as attachments
1784          *
1785          * @param array $urls The object URL list
1786          * @return array an array of attachments
1787          */
1788         private static function processAttachmentUrls(array $urls): array
1789         {
1790                 $attachments = [];
1791                 foreach ($urls as $key => $url) {
1792                         // Not a list but a single URL element
1793                         if (!is_numeric($key)) {
1794                                 continue;
1795                         }
1796
1797                         if (empty($url['@type']) || ($url['@type'] != 'as:Link')) {
1798                                 continue;
1799                         }
1800
1801                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1802                         if (empty($href)) {
1803                                 continue;
1804                         }
1805
1806                         $mediatype = JsonLD::fetchElement($url, 'as:mediaType');
1807                         if (empty($mediatype)) {
1808                                 continue;
1809                         }
1810
1811                         $filetype = strtolower(substr($mediatype, 0, strpos($mediatype, '/')));
1812
1813                         if ($filetype == 'audio') {
1814                                 $attachments[] = ['type' => $filetype, 'mediaType' => $mediatype, 'url' => $href, 'height' => null, 'size' => null, 'name' => ''];
1815                         } elseif ($filetype == 'video') {
1816                                 $height = (int)JsonLD::fetchElement($url, 'as:height', '@value');
1817                                 // PeerTube audio-only track
1818                                 if ($height === 0) {
1819                                         continue;
1820                                 }
1821
1822                                 $size = (int)JsonLD::fetchElement($url, 'pt:size', '@value');
1823                                 $attachments[] = ['type' => $filetype, 'mediaType' => $mediatype, 'url' => $href, 'height' => $height, 'size' => $size, 'name' => ''];
1824                         } elseif (in_array($mediatype, ['application/x-bittorrent', 'application/x-bittorrent;x-scheme-handler/magnet'])) {
1825                                 $height = (int)JsonLD::fetchElement($url, 'as:height', '@value');
1826
1827                                 // For Torrent links we always store the highest resolution
1828                                 if (!empty($attachments[$mediatype]['height']) && ($height < $attachments[$mediatype]['height'])) {
1829                                         continue;
1830                                 }
1831
1832                                 $attachments[$mediatype] = ['type' => $mediatype, 'mediaType' => $mediatype, 'url' => $href, 'height' => $height, 'size' => null, 'name' => ''];
1833                         } elseif ($mediatype == 'application/x-mpegURL') {
1834                                 // PeerTube exception, actual video link is in the tags of this URL element
1835                                 $attachments = array_merge($attachments, self::processAttachmentUrls($url['as:tag']));
1836                         }
1837                 }
1838
1839                 return array_values($attachments);
1840         }
1841
1842         /**
1843          * Fetches data from the object part of an activity
1844          *
1845          * @param array $object
1846          *
1847          * @return array|bool Object data or FALSE if $object does not contain @id element
1848          * @throws \Exception
1849          */
1850         private static function processObject(array $object)
1851         {
1852                 if (!JsonLD::fetchElement($object, '@id')) {
1853                         return false;
1854                 }
1855
1856                 $object_data = self::getObjectDataFromActivity($object);
1857
1858                 $receiverdata = self::getReceivers($object, $object_data['actor'] ?? '', $object_data['tags'], true, false);
1859                 $receivers = $reception_types = [];
1860                 foreach ($receiverdata as $key => $data) {
1861                         $receivers[$key] = $data['uid'];
1862                         $reception_types[$data['uid']] = $data['type'] ?? 0;
1863                 }
1864
1865                 $object_data['receiver_urls']  = self::getReceiverURL($object);
1866                 $object_data['receiver']       = $receivers;
1867                 $object_data['reception_type'] = $reception_types;
1868
1869                 $object_data['unlisted'] = in_array(-1, $object_data['receiver']);
1870                 unset($object_data['receiver'][-1]);
1871                 unset($object_data['reception_type'][-1]);
1872
1873                 return $object_data;
1874         }
1875
1876         /**
1877          * Create an object data array from a given activity
1878          *
1879          * @param array $object
1880          *
1881          * @return array Object data
1882          */
1883         public static function getObjectDataFromActivity(array $object): array
1884         {
1885                 $object_data = [];
1886                 $object_data['object_type'] = JsonLD::fetchElement($object, '@type');
1887                 $object_data['id'] = JsonLD::fetchElement($object, '@id');
1888                 $object_data['reply-to-id'] = JsonLD::fetchElement($object, 'as:inReplyTo', '@id');
1889
1890                 // An empty "id" field is translated to "./" by the compactor, so we have to check for this content
1891                 if (empty($object_data['reply-to-id']) || ($object_data['reply-to-id'] == './')) {
1892                         $object_data['reply-to-id'] = $object_data['id'];
1893
1894                         // On activities the "reply to" is the id of the object it refers to
1895                         if (in_array($object_data['object_type'], array_merge(self::ACTIVITY_TYPES, ['as:Announce']))) {
1896                                 $object_id = JsonLD::fetchElement($object, 'as:object', '@id');
1897                                 if (!empty($object_id)) {
1898                                         $object_data['reply-to-id'] = $object_id;
1899                                 }
1900                         }
1901                 } else {
1902                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
1903                         $replyToId = Item::getURIByLink($object_data['reply-to-id']);
1904                         if (!empty($replyToId) && ($object_data['reply-to-id'] != $replyToId)) {
1905                                 Logger::notice('Fix wrong reply-to', ['received' => $object_data['reply-to-id'], 'correct' => $replyToId]);
1906                                 $object_data['reply-to-id'] = $replyToId;
1907                         }
1908                 }
1909
1910                 $object_data['published'] = JsonLD::fetchElement($object, 'as:published', '@value');
1911                 $object_data['updated'] = JsonLD::fetchElement($object, 'as:updated', '@value');
1912
1913                 if (empty($object_data['updated'])) {
1914                         $object_data['updated'] = $object_data['published'];
1915                 }
1916
1917                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
1918                         $object_data['published'] = $object_data['updated'];
1919                 }
1920
1921                 $actor = JsonLD::fetchElement($object, 'as:attributedTo', '@id');
1922                 if (empty($actor)) {
1923                         $actor = JsonLD::fetchElement($object, 'as:actor', '@id');
1924                 }
1925
1926                 $location = JsonLD::fetchElement($object, 'as:location', 'as:name', '@type', 'as:Place');
1927                 $location = JsonLD::fetchElement($location, 'location', '@value');
1928                 if ($location) {
1929                         // Some AP software allow formatted text in post location, so we run all the text converters we have to boil
1930                         // down to HTML and then finally format to plaintext.
1931                         $location = Markdown::convert($location);
1932                         $location = BBCode::toPlaintext($location);
1933                 }
1934
1935                 $object_data['sc:identifier'] = JsonLD::fetchElement($object, 'sc:identifier', '@value');
1936                 $object_data['diaspora:guid'] = JsonLD::fetchElement($object, 'diaspora:guid', '@value');
1937                 $object_data['diaspora:comment'] = JsonLD::fetchElement($object, 'diaspora:comment', '@value');
1938                 $object_data['diaspora:like'] = JsonLD::fetchElement($object, 'diaspora:like', '@value');
1939                 $object_data['actor'] = $object_data['author'] = $actor;
1940                 $element = JsonLD::fetchElement($object, 'as:context', '@id');
1941                 $object_data['context'] = $element != './' ? $element : null;
1942                 $element = JsonLD::fetchElement($object, 'ostatus:conversation', '@id');
1943                 $object_data['conversation'] = $element != './' ? $element : null;
1944                 $object_data['sensitive'] = JsonLD::fetchElement($object, 'as:sensitive');
1945                 $object_data['name'] = JsonLD::fetchElement($object, 'as:name', '@value');
1946                 $object_data['summary'] = JsonLD::fetchElement($object, 'as:summary', '@value');
1947                 $object_data['content'] = JsonLD::fetchElement($object, 'as:content', '@value');
1948                 $object_data['mediatype'] = JsonLD::fetchElement($object, 'as:mediaType', '@value');
1949                 $object_data = self::getSource($object, $object_data);
1950                 $object_data['start-time'] = JsonLD::fetchElement($object, 'as:startTime', '@value');
1951                 $object_data['end-time'] = JsonLD::fetchElement($object, 'as:endTime', '@value');
1952                 $object_data['location'] = $location;
1953                 $object_data['latitude'] = JsonLD::fetchElement($object, 'as:location', 'as:latitude', '@type', 'as:Place');
1954                 $object_data['latitude'] = JsonLD::fetchElement($object_data, 'latitude', '@value');
1955                 $object_data['longitude'] = JsonLD::fetchElement($object, 'as:location', 'as:longitude', '@type', 'as:Place');
1956                 $object_data['longitude'] = JsonLD::fetchElement($object_data, 'longitude', '@value');
1957                 $object_data['attachments'] = self::processAttachments(JsonLD::fetchElementArray($object, 'as:attachment') ?? []);
1958                 $object_data['tags'] = self::processTags(JsonLD::fetchElementArray($object, 'as:tag') ?? []);
1959                 $object_data['emojis'] = self::processEmojis(JsonLD::fetchElementArray($object, 'as:tag', null, '@type', 'toot:Emoji') ?? []);
1960                 $object_data['languages'] = self::processLanguages(JsonLD::fetchElementArray($object, 'sc:inLanguage') ?? []);
1961                 $object_data['generator'] = JsonLD::fetchElement($object, 'as:generator', 'as:name', '@type', 'as:Application');
1962                 $object_data['generator'] = JsonLD::fetchElement($object_data, 'generator', '@value');
1963                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'as:url', '@id');
1964
1965                 // Special treatment for Hubzilla links
1966                 if (is_array($object_data['alternate-url'])) {
1967                         $object_data['alternate-url'] = JsonLD::fetchElement($object_data['alternate-url'], 'as:href', '@id');
1968
1969                         if (!is_string($object_data['alternate-url'])) {
1970                                 $object_data['alternate-url'] = JsonLD::fetchElement($object['as:url'], 'as:href', '@id');
1971                         }
1972                 }
1973
1974                 if (!empty($object_data['alternate-url']) && !Network::isValidHttpUrl($object_data['alternate-url'])) {
1975                         $object_data['alternate-url'] = null;
1976                 }
1977
1978                 if (in_array($object_data['object_type'], ['as:Audio', 'as:Video'])) {
1979                         $object_data['alternate-url'] = self::extractAlternateUrl($object['as:url'] ?? []) ?: $object_data['alternate-url'];
1980                         $object_data['attachments'] = array_merge($object_data['attachments'], self::processAttachmentUrls($object['as:url'] ?? []));
1981                 }
1982
1983                 // Support for quoted posts (Pleroma, Fedibird and Misskey)
1984                 $object_data['quote-url'] = JsonLD::fetchElement($object, 'as:quoteUrl', '@value');
1985                 if (empty($object_data['quote-url'])) {
1986                         $object_data['quote-url'] = JsonLD::fetchElement($object, 'fedibird:quoteUri', '@value');
1987                 }
1988                 if (empty($object_data['quote-url'])) {
1989                         $object_data['quote-url'] = JsonLD::fetchElement($object, 'misskey:_misskey_quote', '@value');
1990                 }
1991
1992                 // Misskey adds some data to the standard "content" value for quoted posts for backwards compatibility.
1993                 // Their own "_misskey_content" value does then contain the content without this extra data.
1994                 if (!empty($object_data['quote-url'])) {
1995                         $misskey_content = JsonLD::fetchElement($object, 'misskey:_misskey_content', '@value');
1996                         if (!empty($misskey_content)) {
1997                                 $object_data['content'] = $misskey_content;
1998                         }
1999                 }
2000
2001                 // For page types we expect that the alternate url posts to some page.
2002                 // So we add this to the attachments if it differs from the id.
2003                 // Currently only Lemmy is using the page type.
2004                 if (($object_data['object_type'] == 'as:Page') && !empty($object_data['alternate-url']) && !Strings::compareLink($object_data['alternate-url'], $object_data['id'])) {
2005                         $object_data['attachments'][] = ['url' => $object_data['alternate-url']];
2006                         $object_data['alternate-url'] = null;
2007                 }
2008
2009                 if ($object_data['object_type'] == 'as:Question') {
2010                         $object_data['question'] = self::processQuestion($object);
2011                 }
2012
2013                 return $object_data;
2014         }
2015
2016         /**
2017          * Add an object id to the list of arrived activities
2018          *
2019          * @param string $id
2020          *
2021          * @return void
2022          */
2023         private static function addArrivedId(string $id)
2024         {
2025                 DBA::delete('arrived-activity', ["`received` < ?", DateTimeFormat::utc('now - 5 minutes')]);
2026                 DBA::insert('arrived-activity', ['object-id' => $id, 'received' => DateTimeFormat::utcNow()], Database::INSERT_IGNORE);
2027         }
2028
2029         /**
2030          * Checks if the given object already arrived before
2031          *
2032          * @param string $id
2033          *
2034          * @return boolean
2035          */
2036         private static function hasArrived(string $id): bool
2037         {
2038                 return DBA::exists('arrived-activity', ['object-id' => $id]);
2039         }
2040 }