src/Protocol/ActivityPub/Receiver.php

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