src/Protocol/ActivityPub/Receiver.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2020, Friendica
   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\Model\Contact;
  31 use Friendica\Model\APContact;
  32 use Friendica\Model\Item;
  33 use Friendica\Model\User;
  34 use Friendica\Protocol\Activity;
  35 use Friendica\Protocol\ActivityPub;
  36 use Friendica\Util\HTTPSignature;
  37 use Friendica\Util\JsonLD;
  38 use Friendica\Util\LDSignature;
  39 use Friendica\Util\Strings;
  40
  41 /**
  42  * ActivityPub Receiver Protocol class
  43  *
  44  * To-Do:
  45  * @todo Undo Announce
  46  *
  47  * Check what this is meant to do:
  48  * - Add
  49  * - Block
  50  * - Flag
  51  * - Remove
  52  * - Undo Block
  53  */
  54 class Receiver
  55 {
  56         const PUBLIC_COLLECTION = 'as:Public';
  57         const ACCOUNT_TYPES = ['as:Person', 'as:Organization', 'as:Service', 'as:Group', 'as:Application'];
  58         const CONTENT_TYPES = ['as:Note', 'as:Article', 'as:Video', 'as:Image', 'as:Event', 'as:Audio'];
  59         const ACTIVITY_TYPES = ['as:Like', 'as:Dislike', 'as:Accept', 'as:Reject', 'as:TentativeAccept'];
  60
  61         const TARGET_UNKNOWN = 0;
  62         const TARGET_TO = 1;
  63         const TARGET_CC = 2;
  64         const TARGET_BTO = 3;
  65         const TARGET_BCC = 4;
  66         const TARGET_FOLLOWER = 5;
  67         const TARGET_ANSWER = 6;
  68         const TARGET_GLOBAL = 7;
  69
  70         /**
  71          * Checks if the web request is done for the AP protocol
  72          *
  73          * @return bool is it AP?
  74          */
  75         public static function isRequest()
  76         {
  77                 return stristr($_SERVER['HTTP_ACCEPT'] ?? '', 'application/activity+json') ||
  78                         stristr($_SERVER['HTTP_ACCEPT'] ?? '', 'application/ld+json');
  79         }
  80
  81         /**
  82          * Checks incoming message from the inbox
  83          *
  84          * @param         $body
  85          * @param         $header
  86          * @param integer $uid User ID
  87          * @throws \Exception
  88          */
  89         public static function processInbox($body, $header, $uid)
  90         {
  91                 $http_signer = HTTPSignature::getSigner($body, $header);
  92                 if (empty($http_signer)) {
  93                         Logger::warning('Invalid HTTP signature, message will be discarded.');
  94                         return;
  95                 } else {
  96                         Logger::info('Valid HTTP signature', ['signer' => $http_signer]);
  97                 }
  98
  99                 $signer = [$http_signer];
 100                 $activity = json_decode($body, true);
 101
 102                 if (empty($activity)) {
 103                         Logger::warning('Invalid body.');
 104                         return;
 105                 }
 106
 107                 $ldactivity = JsonLD::compact($activity);
 108
 109                 $actor = JsonLD::fetchElement($ldactivity, 'as:actor', '@id');
 110
 111                 Logger::info('Message for user ' . $uid . ' is from actor ' . $actor);
 112
 113                 if (LDSignature::isSigned($activity)) {
 114                         $ld_signer = LDSignature::getSigner($activity);
 115                         if (empty($ld_signer)) {
 116                                 Logger::log('Invalid JSON-LD signature from ' . $actor, Logger::DEBUG);
 117                         } elseif ($ld_signer != $http_signer) {
 118                                 $signer[] = $ld_signer;
 119                         }
 120                         if (!empty($ld_signer && ($actor == $http_signer))) {
 121                                 Logger::log('The HTTP and the JSON-LD signature belong to ' . $ld_signer, Logger::DEBUG);
 122                                 $trust_source = true;
 123                         } elseif (!empty($ld_signer)) {
 124                                 Logger::log('JSON-LD signature is signed by ' . $ld_signer, Logger::DEBUG);
 125                                 $trust_source = true;
 126                         } elseif ($actor == $http_signer) {
 127                                 Logger::log('Bad JSON-LD signature, but HTTP signer fits the actor.', Logger::DEBUG);
 128                                 $trust_source = true;
 129                         } else {
 130                                 Logger::log('Invalid JSON-LD signature and the HTTP signer is different.', Logger::DEBUG);
 131                                 $trust_source = false;
 132                         }
 133                 } elseif ($actor == $http_signer) {
 134                         Logger::log('Trusting post without JSON-LD signature, The actor fits the HTTP signer.', Logger::DEBUG);
 135                         $trust_source = true;
 136                 } else {
 137                         Logger::log('No JSON-LD signature, different actor.', Logger::DEBUG);
 138                         $trust_source = false;
 139                 }
 140
 141                 self::processActivity($ldactivity, $body, $uid, $trust_source, true, $signer);
 142         }
 143
 144         /**
 145          * Fetches the object type for a given object id
 146          *
 147          * @param array   $activity
 148          * @param string  $object_id Object ID of the the provided object
 149          * @param integer $uid       User ID
 150          *
 151          * @return string with object type
 152          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 153          * @throws \ImagickException
 154          */
 155         private static function fetchObjectType($activity, $object_id, $uid = 0)
 156         {
 157                 if (!empty($activity['as:object'])) {
 158                         $object_type = JsonLD::fetchElement($activity['as:object'], '@type');
 159                         if (!empty($object_type)) {
 160                                 return $object_type;
 161                         }
 162                 }
 163
 164                 if (Item::exists(['uri' => $object_id, 'gravity' => [GRAVITY_PARENT, GRAVITY_COMMENT]])) {
 165                         // We just assume "note" since it doesn't make a difference for the further processing
 166                         return 'as:Note';
 167                 }
 168
 169                 $profile = APContact::getByURL($object_id);
 170                 if (!empty($profile['type'])) {
 171                         return 'as:' . $profile['type'];
 172                 }
 173
 174                 $data = ActivityPub::fetchContent($object_id, $uid);
 175                 if (!empty($data)) {
 176                         $object = JsonLD::compact($data);
 177                         $type = JsonLD::fetchElement($object, '@type');
 178                         if (!empty($type)) {
 179                                 return $type;
 180                         }
 181                 }
 182
 183                 return null;
 184         }
 185
 186         /**
 187          * Prepare the object array
 188          *
 189          * @param array   $activity     Array with activity data
 190          * @param integer $uid          User ID
 191          * @param boolean $push         Message had been pushed to our system
 192          * @param boolean $trust_source Do we trust the source?
 193          *
 194          * @return array with object data
 195          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 196          * @throws \ImagickException
 197          */
 198         public static function prepareObjectData($activity, $uid, $push, &$trust_source)
 199         {
 200                 $id = JsonLD::fetchElement($activity, '@id');
 201                 if (!empty($id) && !$trust_source) {
 202                         $fetched_activity = ActivityPub::fetchContent($id, $uid ?? 0);
 203                         if (!empty($fetched_activity)) {
 204                                 $object = JsonLD::compact($fetched_activity);
 205                                 $fetched_id = JsonLD::fetchElement($object, '@id');
 206                                 if ($fetched_id == $id) {
 207                                         Logger::info('Activity had been fetched successfully', ['id' => $id]);
 208                                         $trust_source = true;
 209                                         $activity = $object;
 210                                 } else {
 211                                         Logger::info('Activity id is not equal', ['id' => $id, 'fetched' => $fetched_id]);
 212                                 }
 213                         } else {
 214                                 Logger::info('Activity could not been fetched', ['id' => $id]);
 215                         }
 216                 }
 217
 218                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 219                 if (empty($actor)) {
 220                         Logger::info('Empty actor', ['activity' => $activity]);
 221                         return [];
 222                 }
 223
 224                 $type = JsonLD::fetchElement($activity, '@type');
 225
 226                 // Fetch all receivers from to, cc, bto and bcc
 227                 $receiverdata = self::getReceivers($activity, $actor);
 228                 $receivers = $reception_types = [];
 229                 foreach ($receiverdata as $key => $data) {
 230                         $receivers[$key] = $data['uid'];
 231                         $reception_types[$data['uid']] = $data['type'] ?? 0;
 232                 }
 233
 234                 // When it is a delivery to a personal inbox we add that user to the receivers
 235                 if (!empty($uid)) {
 236                         $additional = ['uid:' . $uid => $uid];
 237                         $receivers = array_merge($receivers, $additional);
 238                         if (empty($reception_types[$uid]) || in_array($reception_types[$uid], [self::TARGET_UNKNOWN, self::TARGET_FOLLOWER, self::TARGET_ANSWER, self::TARGET_GLOBAL])) {
 239                                 $reception_types[$uid] = self::TARGET_BCC;
 240                         }
 241                 } else {
 242                         // We possibly need some user to fetch private content,
 243                         // so we fetch the first out ot the list.
 244                         $uid = self::getFirstUserFromReceivers($receivers);
 245                 }
 246
 247                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 248                 if (empty($object_id)) {
 249                         Logger::log('No object found', Logger::DEBUG);
 250                         return [];
 251                 }
 252
 253                 if (!is_string($object_id)) {
 254                         Logger::info('Invalid object id', ['object' => $object_id]);
 255                         return [];
 256                 }
 257
 258                 $object_type = self::fetchObjectType($activity, $object_id, $uid);
 259
 260                 // Fetch the content only on activities where this matters
 261                 if (in_array($type, ['as:Create', 'as:Update', 'as:Announce'])) {
 262                         // Always fetch on "Announce"
 263                         $object_data = self::fetchObject($object_id, $activity['as:object'], $trust_source && ($type != 'as:Announce'), $uid);
 264                         if (empty($object_data)) {
 265                                 Logger::log("Object data couldn't be processed", Logger::DEBUG);
 266                                 return [];
 267                         }
 268
 269                         $object_data['object_id'] = $object_id;
 270
 271                         if ($type == 'as:Announce') {
 272                                 $object_data['push'] = false;
 273                         } else {
 274                                 $object_data['push'] = $push;
 275                         }
 276
 277                         // Test if it is an answer to a mail
 278                         if (DBA::exists('mail', ['uri' => $object_data['reply-to-id']])) {
 279                                 $object_data['directmessage'] = true;
 280                         } else {
 281                                 $object_data['directmessage'] = JsonLD::fetchElement($activity, 'litepub:directMessage');
 282                         }
 283                 } elseif (in_array($type, array_merge(self::ACTIVITY_TYPES, ['as:Follow'])) && in_array($object_type, self::CONTENT_TYPES)) {
 284                         // Create a mostly empty array out of the activity data (instead of the object).
 285                         // This way we later don't have to check for the existence of ech individual array element.
 286                         $object_data = self::processObject($activity);
 287                         $object_data['name'] = $type;
 288                         $object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 289                         $object_data['object_id'] = $object_id;
 290                         $object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
 291                 } elseif (in_array($type, ['as:Add'])) {
 292                         $object_data = [];
 293                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 294                         $object_data['target_id'] = JsonLD::fetchElement($activity, 'as:target', '@id');
 295                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 296                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 297                         $object_data['object_content'] = JsonLD::fetchElement($activity['as:object'], 'as:content', '@type');
 298                 } else {
 299                         $object_data = [];
 300                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 301                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 302                         $object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor', '@id');
 303                         $object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
 304                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 305
 306                         // An Undo is done on the object of an object, so we need that type as well
 307                         if (($type == 'as:Undo') && !empty($object_data['object_object'])) {
 308                                 $object_data['object_object_type'] = self::fetchObjectType([], $object_data['object_object'], $uid);
 309                         }
 310                 }
 311
 312                 $object_data = self::addActivityFields($object_data, $activity);
 313
 314                 if (empty($object_data['object_type'])) {
 315                         $object_data['object_type'] = $object_type;
 316                 }
 317
 318                 $object_data['type'] = $type;
 319                 $object_data['actor'] = $actor;
 320                 $object_data['item_receiver'] = $receivers;
 321                 $object_data['receiver'] = array_merge($object_data['receiver'] ?? [], $receivers);
 322                 $object_data['reception_type'] = array_merge($object_data['reception_type'] ?? [], $reception_types);
 323
 324                 $author = $object_data['author'] ?? $actor;
 325                 if (!empty($author) && !empty($object_data['id'])) {
 326                         $author_host = parse_url($author, PHP_URL_HOST);
 327                         $id_host = parse_url($object_data['id'], PHP_URL_HOST);
 328                         if ($author_host == $id_host) {
 329                                 Logger::info('Valid hosts', ['type' => $type, 'host' => $id_host]);
 330                         } else {
 331                                 Logger::notice('Differing hosts on author and id', ['type' => $type, 'author' => $author_host, 'id' => $id_host]);
 332                                 $trust_source = false;
 333                         }
 334                 }
 335
 336                 Logger::log('Processing ' . $object_data['type'] . ' ' . $object_data['object_type'] . ' ' . $object_data['id'], Logger::DEBUG);
 337
 338                 return $object_data;
 339         }
 340
 341         /**
 342          * Fetches the first user id from the receiver array
 343          *
 344          * @param array $receivers Array with receivers
 345          * @return integer user id;
 346          */
 347         public static function getFirstUserFromReceivers($receivers)
 348         {
 349                 foreach ($receivers as $receiver) {
 350                         if (!empty($receiver)) {
 351                                 return $receiver;
 352                         }
 353                 }
 354                 return 0;
 355         }
 356
 357         /**
 358          * Processes the activity object
 359          *
 360          * @param array   $activity     Array with activity data
 361          * @param string  $body
 362          * @param integer $uid          User ID
 363          * @param boolean $trust_source Do we trust the source?
 364          * @param boolean $push         Message had been pushed to our system
 365          * @throws \Exception
 366          */
 367         public static function processActivity($activity, string $body = '', int $uid = null, bool $trust_source = false, bool $push = false, array $signer = [])
 368         {
 369                 $type = JsonLD::fetchElement($activity, '@type');
 370                 if (!$type) {
 371                         Logger::info('Empty type', ['activity' => $activity]);
 372                         return;
 373                 }
 374
 375                 if (!JsonLD::fetchElement($activity, 'as:object', '@id')) {
 376                         Logger::info('Empty object', ['activity' => $activity]);
 377                         return;
 378                 }
 379
 380                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 381                 if (empty($actor)) {
 382                         Logger::info('Empty actor', ['activity' => $activity]);
 383                         return;
 384                 }
 385
 386                 if (is_array($activity['as:object'])) {
 387                         $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
 388                 } else {
 389                         $attributed_to = '';
 390                 }
 391
 392                 // Test the provided signatures against the actor and "attributedTo"
 393                 if ($trust_source) {
 394                         if (!empty($attributed_to) && !empty($actor)) {
 395                                 $trust_source = (in_array($actor, $signer) && in_array($attributed_to, $signer));
 396                         } else {
 397                                 $trust_source = in_array($actor, $signer);
 398                         }
 399                 }
 400
 401                 // $trust_source is called by reference and is set to true if the content was retrieved successfully
 402                 $object_data = self::prepareObjectData($activity, $uid, $push, $trust_source);
 403                 if (empty($object_data)) {
 404                         Logger::info('No object data found', ['activity' => $activity]);
 405                         return;
 406                 }
 407
 408                 if (!$trust_source) {
 409                         Logger::info('Activity trust could not be achieved.',  ['id' => $object_data['object_id'], 'type' => $type, 'signer' => $signer, 'actor' => $actor, 'attributedTo' => $attributed_to]);
 410                         return;
 411                 }
 412
 413                 if (!empty($body) && empty($object_data['raw'])) {
 414                         $object_data['raw'] = $body;
 415                 }
 416
 417                 // Internal flag for thread completion. See Processor.php
 418                 if (!empty($activity['thread-completion'])) {
 419                         $object_data['thread-completion'] = $activity['thread-completion'];
 420                 }
 421
 422                 switch ($type) {
 423                         case 'as:Create':
 424                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 425                                         $item = ActivityPub\Processor::createItem($object_data);
 426                                         ActivityPub\Processor::postItem($object_data, $item);
 427                                 }
 428                                 break;
 429
 430                         case 'as:Add':
 431                                 if ($object_data['object_type'] == 'as:tag') {
 432                                         ActivityPub\Processor::addTag($object_data);
 433                                 }
 434                                 break;
 435
 436                         case 'as:Announce':
 437                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 438                                         $object_data['thread-completion'] = true;
 439
 440                                         $item = ActivityPub\Processor::createItem($object_data);
 441                                         ActivityPub\Processor::postItem($object_data, $item);
 442
 443                                         $announce_object_data = self::processObject($activity);
 444                                         $announce_object_data['name'] = $type;
 445                                         $announce_object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 446                                         $announce_object_data['object_id'] = $object_data['object_id'];
 447                                         $announce_object_data['object_type'] = $object_data['object_type'];
 448                                         $announce_object_data['push'] = $push;
 449
 450                                         if (!empty($body)) {
 451                                                 $announce_object_data['raw'] = $body;
 452                                         }
 453
 454                                         ActivityPub\Processor::createActivity($announce_object_data, Activity::ANNOUNCE);
 455                                 }
 456                                 break;
 457
 458                         case 'as:Like':
 459                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 460                                         ActivityPub\Processor::createActivity($object_data, Activity::LIKE);
 461                                 }
 462                                 break;
 463
 464                         case 'as:Dislike':
 465                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 466                                         ActivityPub\Processor::createActivity($object_data, Activity::DISLIKE);
 467                                 }
 468                                 break;
 469
 470                         case 'as:TentativeAccept':
 471                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 472                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDMAYBE);
 473                                 }
 474                                 break;
 475
 476                         case 'as:Update':
 477                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 478                                         ActivityPub\Processor::updateItem($object_data);
 479                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 480                                         ActivityPub\Processor::updatePerson($object_data);
 481                                 }
 482                                 break;
 483
 484                         case 'as:Delete':
 485                                 if ($object_data['object_type'] == 'as:Tombstone') {
 486                                         ActivityPub\Processor::deleteItem($object_data);
 487                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 488                                         ActivityPub\Processor::deletePerson($object_data);
 489                                 }
 490                                 break;
 491
 492                         case 'as:Follow':
 493                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 494                                         ActivityPub\Processor::followUser($object_data);
 495                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 496                                         $object_data['reply-to-id'] = $object_data['object_id'];
 497                                         ActivityPub\Processor::createActivity($object_data, Activity::FOLLOW);
 498                                 }
 499                                 break;
 500
 501                         case 'as:Accept':
 502                                 if ($object_data['object_type'] == 'as:Follow') {
 503                                         ActivityPub\Processor::acceptFollowUser($object_data);
 504                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 505                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTEND);
 506                                 }
 507                                 break;
 508
 509                         case 'as:Reject':
 510                                 if ($object_data['object_type'] == 'as:Follow') {
 511                                         ActivityPub\Processor::rejectFollowUser($object_data);
 512                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 513                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDNO);
 514                                 }
 515                                 break;
 516
 517                         case 'as:Undo':
 518                                 if (($object_data['object_type'] == 'as:Follow') &&
 519                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 520                                         ActivityPub\Processor::undoFollowUser($object_data);
 521                                 } elseif (($object_data['object_type'] == 'as:Accept') &&
 522                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 523                                         ActivityPub\Processor::rejectFollowUser($object_data);
 524                                 } elseif (in_array($object_data['object_type'], self::ACTIVITY_TYPES) &&
 525                                         in_array($object_data['object_object_type'], self::CONTENT_TYPES)) {
 526                                         ActivityPub\Processor::undoActivity($object_data);
 527                                 }
 528                                 break;
 529
 530                         default:
 531                                 Logger::log('Unknown activity: ' . $type . ' ' . $object_data['object_type'], Logger::DEBUG);
 532                                 break;
 533                 }
 534         }
 535
 536         /**
 537          * Fetch the receiver list from an activity array
 538          *
 539          * @param array   $activity
 540          * @param string  $actor
 541          * @param array   $tags
 542          * @param boolean $fetch_unlisted
 543          *
 544          * @return array with receivers (user id)
 545          * @throws \Exception
 546          */
 547         private static function getReceivers($activity, $actor, $tags = [], $fetch_unlisted = false)
 548         {
 549                 $reply = $receivers = [];
 550
 551                 // When it is an answer, we inherite the receivers from the parent
 552                 $replyto = JsonLD::fetchElement($activity, 'as:inReplyTo', '@id');
 553                 if (!empty($replyto)) {
 554                         $reply = [$replyto];
 555
 556                         // Fix possibly wrong item URI (could be an answer to a plink uri)
 557                         $fixedReplyTo = Item::getURIByLink($replyto);
 558                         if (!empty($fixedReplyTo)) {
 559                                 $reply[] = $fixedReplyTo;
 560                         }
 561                 }
 562
 563                 // Fetch all posts that refer to the object id
 564                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 565                 if (!empty($object_id)) {
 566                         $reply[] = $object_id;
 567                 }
 568
 569                 if (!empty($reply)) {
 570                         $parents = Item::select(['uid'], ['uri' => $reply]);
 571                         while ($parent = Item::fetch($parents)) {
 572                                 $receivers['uid:' . $parent['uid']] = ['uid' => $parent['uid'], 'type' => self::TARGET_ANSWER];
 573                         }
 574                 }
 575
 576                 if (!empty($actor)) {
 577                         $profile = APContact::getByURL($actor);
 578                         $followers = $profile['followers'] ?? '';
 579
 580                         Logger::log('Actor: ' . $actor . ' - Followers: ' . $followers, Logger::DEBUG);
 581                 } else {
 582                         Logger::info('Empty actor', ['activity' => $activity]);
 583                         $followers = '';
 584                 }
 585
 586                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
 587                         $receiver_list = JsonLD::fetchElementArray($activity, $element, '@id');
 588                         if (empty($receiver_list)) {
 589                                 continue;
 590                         }
 591
 592                         foreach ($receiver_list as $receiver) {
 593                                 if ($receiver == self::PUBLIC_COLLECTION) {
 594                                         $receivers['uid:0'] = ['uid' => 0, 'type' => self::TARGET_GLOBAL];
 595                                 }
 596
 597                                 // Add receiver "-1" for unlisted posts
 598                                 if ($fetch_unlisted && ($receiver == self::PUBLIC_COLLECTION) && ($element == 'as:cc')) {
 599                                         $receivers['uid:-1'] = ['uid' => -1, 'type' => self::TARGET_GLOBAL];
 600                                 }
 601
 602                                 // Fetch the receivers for the public and the followers collection
 603                                 if (in_array($receiver, [$followers, self::PUBLIC_COLLECTION]) && !empty($actor)) {
 604                                         $receivers = self::getReceiverForActor($actor, $tags, $receivers);
 605                                         continue;
 606                                 }
 607
 608                                 // Fetching all directly addressed receivers
 609                                 $condition = ['self' => true, 'nurl' => Strings::normaliseLink($receiver)];
 610                                 $contact = DBA::selectFirst('contact', ['uid', 'contact-type'], $condition);
 611                                 if (!DBA::isResult($contact)) {
 612                                         continue;
 613                                 }
 614
 615                                 // Check if the potential receiver is following the actor
 616                                 // Exception: The receiver is targetted via "to" or this is a comment
 617                                 if ((($element != 'as:to') && empty($replyto)) || ($contact['contact-type'] == Contact::TYPE_COMMUNITY)) {
 618                                         $networks = Protocol::FEDERATED;
 619                                         $condition = ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
 620                                                 'network' => $networks, 'archive' => false, 'pending' => false, 'uid' => $contact['uid']];
 621
 622                                         // Forum posts are only accepted from forum contacts
 623                                         if ($contact['contact-type'] == Contact::TYPE_COMMUNITY) {
 624                                                 $condition['rel'] = [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER];
 625                                         }
 626
 627                                         if (!DBA::exists('contact', $condition)) {
 628                                                 continue;
 629                                         }
 630                                 }
 631
 632                                 $type = $receivers['uid:' . $contact['uid']]['type'] ?? self::TARGET_UNKNOWN;
 633                                 if (in_array($type, [self::TARGET_UNKNOWN, self::TARGET_FOLLOWER, self::TARGET_ANSWER, self::TARGET_GLOBAL])) {
 634                                         switch ($element) {
 635                                                 case 'as:to':
 636                                                         $type = self::TARGET_TO;
 637                                                         break;
 638                                                 case 'as:cc':
 639                                                         $type = self::TARGET_CC;
 640                                                         break;
 641                                                 case 'as:bto':
 642                                                         $type = self::TARGET_BTO;
 643                                                         break;
 644                                                 case 'as:bcc':
 645                                                         $type = self::TARGET_BCC;
 646                                                         break;
 647                                         }
 648
 649                                         $receivers['uid:' . $contact['uid']] = ['uid' => $contact['uid'], 'type' => $type];
 650                                 }
 651                         }
 652                 }
 653
 654                 self::switchContacts($receivers, $actor);
 655
 656                 return $receivers;
 657         }
 658
 659         /**
 660          * Fetch the receiver list of a given actor
 661          *
 662          * @param string $actor
 663          * @param array  $tags
 664          *
 665          * @return array with receivers (user id)
 666          * @throws \Exception
 667          */
 668         private static function getReceiverForActor($actor, $tags, $receivers)
 669         {
 670                 $basecondition = ['rel' => [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER],
 671                         'network' => Protocol::FEDERATED, 'archive' => false, 'pending' => false];
 672
 673                 $condition = DBA::mergeConditions($basecondition, ['nurl' => Strings::normaliseLink($actor)]);
 674                 $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
 675                 while ($contact = DBA::fetch($contacts)) {
 676                         if (empty($receivers['uid:' . $contact['uid']]) && self::isValidReceiverForActor($contact, $actor, $tags)) {
 677                                 $receivers['uid:' . $contact['uid']] = ['uid' => $contact['uid'], 'type' => self::TARGET_FOLLOWER];
 678                         }
 679                 }
 680                 DBA::close($contacts);
 681
 682                 // The queries are split because of performance issues
 683                 $condition = DBA::mergeConditions($basecondition, ["`alias` IN (?, ?)", Strings::normaliseLink($actor), $actor]);
 684                 $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
 685                 while ($contact = DBA::fetch($contacts)) {
 686                         if (empty($receivers['uid:' . $contact['uid']]) && self::isValidReceiverForActor($contact, $actor, $tags)) {
 687                                 $receivers['uid:' . $contact['uid']] = ['uid' => $contact['uid'], 'type' => self::TARGET_FOLLOWER];
 688                         }
 689                 }
 690                 DBA::close($contacts);
 691                 return $receivers;
 692         }
 693
 694         /**
 695          * Tests if the contact is a valid receiver for this actor
 696          *
 697          * @param array  $contact
 698          * @param string $actor
 699          * @param array  $tags
 700          *
 701          * @return bool with receivers (user id)
 702          * @throws \Exception
 703          */
 704         private static function isValidReceiverForActor($contact, $actor, $tags)
 705         {
 706                 // Public contacts are no valid receiver
 707                 if ($contact['uid'] == 0) {
 708                         return false;
 709                 }
 710
 711                 // Are we following the contact? Then this is a valid receiver
 712                 if (in_array($contact['rel'], [Contact::SHARING, Contact::FRIEND])) {
 713                         return true;
 714                 }
 715
 716                 // When the possible receiver isn't a community, then it is no valid receiver
 717                 $owner = User::getOwnerDataById($contact['uid']);
 718                 if (empty($owner) || ($owner['contact-type'] != Contact::TYPE_COMMUNITY)) {
 719                         return false;
 720                 }
 721
 722                 // Is the community account tagged?
 723                 foreach ($tags as $tag) {
 724                         if ($tag['type'] != 'Mention') {
 725                                 continue;
 726                         }
 727
 728                         if ($tag['href'] == $owner['url']) {
 729                                 return true;
 730                         }
 731                 }
 732
 733                 return false;
 734         }
 735
 736         /**
 737          * Switches existing contacts to ActivityPub
 738          *
 739          * @param integer $cid Contact ID
 740          * @param integer $uid User ID
 741          * @param string  $url Profile URL
 742          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 743          * @throws \ImagickException
 744          */
 745         public static function switchContact($cid, $uid, $url)
 746         {
 747                 if (DBA::exists('contact', ['id' => $cid, 'network' => Protocol::ACTIVITYPUB])) {
 748                         Logger::info('Contact is already ActivityPub', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
 749                         return;
 750                 }
 751
 752                 if (Contact::updateFromProbe($cid)) {
 753                         Logger::info('Update was successful', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
 754                 }
 755
 756                 // Send a new follow request to be sure that the connection still exists
 757                 if (($uid != 0) && DBA::exists('contact', ['id' => $cid, 'rel' => [Contact::SHARING, Contact::FRIEND], 'network' => Protocol::ACTIVITYPUB])) {
 758                         Logger::info('Contact had been switched to ActivityPub. Sending a new follow request.', ['uid' => $uid, 'url' => $url]);
 759                         ActivityPub\Transmitter::sendActivity('Follow', $url, $uid);
 760                 }
 761         }
 762
 763         /**
 764          *
 765          *
 766          * @param $receivers
 767          * @param $actor
 768          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 769          * @throws \ImagickException
 770          */
 771         private static function switchContacts($receivers, $actor)
 772         {
 773                 if (empty($actor)) {
 774                         return;
 775                 }
 776
 777                 foreach ($receivers as $receiver) {
 778                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver['uid'], 'network' => Protocol::OSTATUS, 'nurl' => Strings::normaliseLink($actor)]);
 779                         if (DBA::isResult($contact)) {
 780                                 self::switchContact($contact['id'], $receiver['uid'], $actor);
 781                         }
 782
 783                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver['uid'], 'network' => Protocol::OSTATUS, 'alias' => [Strings::normaliseLink($actor), $actor]]);
 784                         if (DBA::isResult($contact)) {
 785                                 self::switchContact($contact['id'], $receiver['uid'], $actor);
 786                         }
 787                 }
 788         }
 789
 790         /**
 791          *
 792          *
 793          * @param       $object_data
 794          * @param array $activity
 795          *
 796          * @return mixed
 797          */
 798         private static function addActivityFields($object_data, $activity)
 799         {
 800                 if (!empty($activity['published']) && empty($object_data['published'])) {
 801                         $object_data['published'] = JsonLD::fetchElement($activity, 'as:published', '@value');
 802                 }
 803
 804                 if (!empty($activity['diaspora:guid']) && empty($object_data['diaspora:guid'])) {
 805                         $object_data['diaspora:guid'] = JsonLD::fetchElement($activity, 'diaspora:guid', '@value');
 806                 }
 807
 808                 $object_data['service'] = JsonLD::fetchElement($activity, 'as:instrument', 'as:name', '@type', 'as:Service');
 809                 $object_data['service'] = JsonLD::fetchElement($object_data, 'service', '@value');
 810
 811                 if (!empty($object_data['object_id'])) {
 812                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
 813                         $objectId = Item::getURIByLink($object_data['object_id']);
 814                         if (!empty($objectId) && ($object_data['object_id'] != $objectId)) {
 815                                 Logger::notice('Fix wrong object-id', ['received' => $object_data['object_id'], 'correct' => $objectId]);
 816                                 $object_data['object_id'] = $objectId;
 817                         }
 818                 }
 819
 820                 return $object_data;
 821         }
 822
 823         /**
 824          * Fetches the object data from external ressources if needed
 825          *
 826          * @param string  $object_id    Object ID of the the provided object
 827          * @param array   $object       The provided object array
 828          * @param boolean $trust_source Do we trust the provided object?
 829          * @param integer $uid          User ID for the signature that we use to fetch data
 830          *
 831          * @return array|false with trusted and valid object data
 832          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 833          * @throws \ImagickException
 834          */
 835         private static function fetchObject(string $object_id, array $object = [], bool $trust_source = false, int $uid = 0)
 836         {
 837                 // By fetching the type we check if the object is complete.
 838                 $type = JsonLD::fetchElement($object, '@type');
 839
 840                 if (!$trust_source || empty($type)) {
 841                         $data = ActivityPub::fetchContent($object_id, $uid);
 842                         if (!empty($data)) {
 843                                 $object = JsonLD::compact($data);
 844                                 Logger::log('Fetched content for ' . $object_id, Logger::DEBUG);
 845                         } else {
 846                                 Logger::log('Empty content for ' . $object_id . ', check if content is available locally.', Logger::DEBUG);
 847
 848                                 $item = Item::selectFirst([], ['uri' => $object_id]);
 849                                 if (!DBA::isResult($item)) {
 850                                         Logger::log('Object with url ' . $object_id . ' was not found locally.', Logger::DEBUG);
 851                                         return false;
 852                                 }
 853                                 Logger::log('Using already stored item for url ' . $object_id, Logger::DEBUG);
 854                                 $data = ActivityPub\Transmitter::createNote($item);
 855                                 $object = JsonLD::compact($data);
 856                         }
 857
 858                         $id = JsonLD::fetchElement($object, '@id');
 859                         if (empty($id)) {
 860                                 Logger::info('Empty id');
 861                                 return false;
 862                         }
 863
 864                         if ($id != $object_id) {
 865                                 Logger::info('Fetched id differs from provided id', ['provided' => $object_id, 'fetched' => $id]);
 866                                 return false;
 867                         }
 868                 } else {
 869                         Logger::log('Using original object for url ' . $object_id, Logger::DEBUG);
 870                 }
 871
 872                 $type = JsonLD::fetchElement($object, '@type');
 873                 if (empty($type)) {
 874                         Logger::info('Empty type');
 875                         return false;
 876                 }
 877
 878                 // We currently don't handle 'pt:CacheFile', but with this step we avoid logging
 879                 if (in_array($type, self::CONTENT_TYPES) || ($type == 'pt:CacheFile')) {
 880                         $object_data = self::processObject($object);
 881
 882                         if (!empty($data)) {
 883                                 $object_data['raw'] = json_encode($data);
 884                         }
 885                         return $object_data;
 886                 }
 887
 888                 if ($type == 'as:Announce') {
 889                         $object_id = JsonLD::fetchElement($object, 'object', '@id');
 890                         if (empty($object_id) || !is_string($object_id)) {
 891                                 return false;
 892                         }
 893                         return self::fetchObject($object_id, [], false, $uid);
 894                 }
 895
 896                 Logger::log('Unhandled object type: ' . $type, Logger::DEBUG);
 897                 return false;
 898         }
 899
 900         /**
 901          * Convert tags from JSON-LD format into a simplified format
 902          *
 903          * @param array $tags Tags in JSON-LD format
 904          *
 905          * @return array with tags in a simplified format
 906          */
 907         private static function processTags(array $tags)
 908         {
 909                 $taglist = [];
 910
 911                 foreach ($tags as $tag) {
 912                         if (empty($tag)) {
 913                                 continue;
 914                         }
 915
 916                         $element = ['type' => str_replace('as:', '', JsonLD::fetchElement($tag, '@type')),
 917                                 'href' => JsonLD::fetchElement($tag, 'as:href', '@id'),
 918                                 'name' => JsonLD::fetchElement($tag, 'as:name', '@value')];
 919
 920                         if (empty($element['type'])) {
 921                                 continue;
 922                         }
 923
 924                         if (empty($element['href'])) {
 925                                 $element['href'] = $element['name'];
 926                         }
 927
 928                         $taglist[] = $element;
 929                 }
 930                 return $taglist;
 931         }
 932
 933         /**
 934          * Convert emojis from JSON-LD format into a simplified format
 935          *
 936          * @param array $emojis
 937          * @return array with emojis in a simplified format
 938          */
 939         private static function processEmojis(array $emojis)
 940         {
 941                 $emojilist = [];
 942
 943                 foreach ($emojis as $emoji) {
 944                         if (empty($emoji) || (JsonLD::fetchElement($emoji, '@type') != 'toot:Emoji') || empty($emoji['as:icon'])) {
 945                                 continue;
 946                         }
 947
 948                         $url = JsonLD::fetchElement($emoji['as:icon'], 'as:url', '@id');
 949                         $element = ['name' => JsonLD::fetchElement($emoji, 'as:name', '@value'),
 950                                 'href' => $url];
 951
 952                         $emojilist[] = $element;
 953                 }
 954
 955                 return $emojilist;
 956         }
 957
 958         /**
 959          * Convert attachments from JSON-LD format into a simplified format
 960          *
 961          * @param array $attachments Attachments in JSON-LD format
 962          *
 963          * @return array Attachments in a simplified format
 964          */
 965         private static function processAttachments(array $attachments)
 966         {
 967                 $attachlist = [];
 968
 969                 // Removes empty values
 970                 $attachments = array_filter($attachments);
 971
 972                 foreach ($attachments as $attachment) {
 973                         switch (JsonLD::fetchElement($attachment, '@type')) {
 974                                 case 'as:Page':
 975                                         $pageUrl = null;
 976                                         $pageImage = null;
 977
 978                                         $urls = JsonLD::fetchElementArray($attachment, 'as:url');
 979                                         foreach ($urls as $url) {
 980                                                 // Single scalar URL case
 981                                                 if (is_string($url)) {
 982                                                         $pageUrl = $url;
 983                                                         continue;
 984                                                 }
 985
 986                                                 $href = JsonLD::fetchElement($url, 'as:href', '@id');
 987                                                 $mediaType = JsonLD::fetchElement($url, 'as:mediaType', '@value');
 988                                                 if (Strings::startsWith($mediaType, 'image')) {
 989                                                         $pageImage = $href;
 990                                                 } else {
 991                                                         $pageUrl = $href;
 992                                                 }
 993                                         }
 994
 995                                         $attachlist[] = [
 996                                                 'type'  => 'link',
 997                                                 'title' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
 998                                                 'desc'  => JsonLD::fetchElement($attachment, 'as:summary', '@value'),
 999                                                 'url'   => $pageUrl,
1000                                                 'image' => $pageImage,
1001                                         ];
1002                                         break;
1003                                 case 'as:Link':
1004                                         $attachlist[] = [
1005                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1006                                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType', '@value'),
1007                                                 'name' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1008                                                 'url' => JsonLD::fetchElement($attachment, 'as:href', '@id')
1009                                         ];
1010                                         break;
1011                                 case 'as:Image':
1012                                         $mediaType = JsonLD::fetchElement($attachment, 'as:mediaType', '@value');
1013                                         $imageFullUrl = JsonLD::fetchElement($attachment, 'as:url', '@id');
1014                                         $imagePreviewUrl = null;
1015                                         // Multiple URLs?
1016                                         if (!$imageFullUrl && ($urls = JsonLD::fetchElementArray($attachment, 'as:url'))) {
1017                                                 $imageVariants = [];
1018                                                 $previewVariants = [];
1019                                                 foreach ($urls as $url) {
1020                                                         // Scalar URL, no discrimination possible
1021                                                         if (is_string($url)) {
1022                                                                 $imageFullUrl = $url;
1023                                                                 continue;
1024                                                         }
1025
1026                                                         // Not sure what to do with a different Link media type than the base Image, we skip
1027                                                         if ($mediaType != JsonLD::fetchElement($url, 'as:mediaType', '@value')) {
1028                                                                 continue;
1029                                                         }
1030
1031                                                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1032
1033                                                         // Default URL choice if no discriminating width is provided
1034                                                         $imageFullUrl = $href ?? $imageFullUrl;
1035
1036                                                         $width = intval(JsonLD::fetchElement($url, 'as:width', '@value') ?? 1);
1037
1038                                                         if ($href && $width) {
1039                                                                 $imageVariants[$width] = $href;
1040                                                                 // 632 is the ideal width for full screen frio posts, we compute the absolute distance to it
1041                                                                 $previewVariants[abs(632 - $width)] = $href;
1042                                                         }
1043                                                 }
1044
1045                                                 if ($imageVariants) {
1046                                                         // Taking the maximum size image
1047                                                         ksort($imageVariants);
1048                                                         $imageFullUrl = array_pop($imageVariants);
1049
1050                                                         // Taking the minimum number distance to the target distance
1051                                                         ksort($previewVariants);
1052                                                         $imagePreviewUrl = array_shift($previewVariants);
1053                                                 }
1054
1055                                                 unset($imageVariants);
1056                                                 unset($previewVariants);
1057                                         }
1058
1059                                         $attachlist[] = [
1060                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1061                                                 'mediaType' => $mediaType,
1062                                                 'name'  => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1063                                                 'url'   => $imageFullUrl,
1064                                                 'image' => $imagePreviewUrl !== $imageFullUrl ? $imagePreviewUrl : null,
1065                                         ];
1066                                         break;
1067                                 default:
1068                                         $attachlist[] = [
1069                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1070                                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType', '@value'),
1071                                                 'name' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1072                                                 'url' => JsonLD::fetchElement($attachment, 'as:url', '@id')
1073                                         ];
1074                         }
1075                 }
1076
1077                 return $attachlist;
1078         }
1079
1080         /**
1081          * Fetch the original source or content with the "language" Markdown or HTML
1082          *
1083          * @param array $object
1084          * @param array $object_data
1085          *
1086          * @return array
1087          * @throws \Exception
1088          */
1089         private static function getSource($object, $object_data)
1090         {
1091                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/bbcode');
1092                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1093                 if (!empty($object_data['source'])) {
1094                         return $object_data;
1095                 }
1096
1097                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/markdown');
1098                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1099                 if (!empty($object_data['source'])) {
1100                         $object_data['source'] = Markdown::toBBCode($object_data['source']);
1101                         return $object_data;
1102                 }
1103
1104                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/html');
1105                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1106                 if (!empty($object_data['source'])) {
1107                         $object_data['source'] = HTML::toBBCode($object_data['source']);
1108                         return $object_data;
1109                 }
1110
1111                 return $object_data;
1112         }
1113
1114         /**
1115          * Check if the "as:url" element is an array with multiple links
1116          * This is the case with audio and video posts.
1117          * Then the links are added as attachments
1118          *
1119          * @param array $object      The raw object
1120          * @param array $object_data The parsed object data for later processing
1121          * @return array the object data
1122          */
1123         private static function processAttachmentUrls(array $object, array $object_data) {
1124                 // Check if this is some url with multiple links
1125                 if (empty($object['as:url'])) {
1126                         return $object_data;
1127                 }
1128
1129                 $urls = $object['as:url'];
1130                 $keys = array_keys($urls);
1131                 if (!is_numeric(array_pop($keys))) {
1132                         return $object_data;
1133                 }
1134
1135                 $attachments = [];
1136
1137                 foreach ($urls as $url) {
1138                         if (empty($url['@type']) || ($url['@type'] != 'as:Link')) {
1139                                 continue;
1140                         }
1141
1142                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1143                         if (empty($href)) {
1144                                 continue;
1145                         }
1146
1147                         $mediatype = JsonLD::fetchElement($url, 'as:mediaType');
1148                         if (empty($mediatype)) {
1149                                 continue;
1150                         }
1151
1152                         if ($mediatype == 'text/html') {
1153                                 $object_data['alternate-url'] = $href;
1154                         }
1155
1156                         $filetype = strtolower(substr($mediatype, 0, strpos($mediatype, '/')));
1157
1158                         if ($filetype == 'audio') {
1159                                 $attachments[$filetype] = ['type' => $mediatype, 'url' => $href];
1160                         } elseif ($filetype == 'video') {
1161                                 $height = (int)JsonLD::fetchElement($url, 'as:height', '@value');
1162
1163                                 // We save bandwidth by using a moderate height
1164                                 // Peertube normally uses these heights: 240, 360, 480, 720, 1080
1165                                 if (!empty($attachments[$filetype]['height']) &&
1166                                         (($height > 480) || $height < $attachments[$filetype]['height'])) {
1167                                         continue;
1168                                 }
1169
1170                                 $attachments[$filetype] = ['type' => $mediatype, 'url' => $href, 'height' => $height];
1171                         }
1172                 }
1173
1174                 foreach ($attachments as $type => $attachment) {
1175                         $object_data['attachments'][] = ['type' => $type,
1176                                 'mediaType' => $attachment['type'],
1177                                 'name' => '',
1178                                 'url' => $attachment['url']];
1179                 }
1180                 return $object_data;
1181         }
1182
1183         /**
1184          * Fetches data from the object part of an activity
1185          *
1186          * @param array $object
1187          *
1188          * @return array
1189          * @throws \Exception
1190          */
1191         private static function processObject($object)
1192         {
1193                 if (!JsonLD::fetchElement($object, '@id')) {
1194                         return false;
1195                 }
1196
1197                 $object_data = [];
1198                 $object_data['object_type'] = JsonLD::fetchElement($object, '@type');
1199                 $object_data['id'] = JsonLD::fetchElement($object, '@id');
1200                 $object_data['reply-to-id'] = JsonLD::fetchElement($object, 'as:inReplyTo', '@id');
1201
1202                 // An empty "id" field is translated to "./" by the compactor, so we have to check for this content
1203                 if (empty($object_data['reply-to-id']) || ($object_data['reply-to-id'] == './')) {
1204                         $object_data['reply-to-id'] = $object_data['id'];
1205                 } else {
1206                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
1207                         $replyToId = Item::getURIByLink($object_data['reply-to-id']);
1208                         if (!empty($replyToId) && ($object_data['reply-to-id'] != $replyToId)) {
1209                                 Logger::notice('Fix wrong reply-to', ['received' => $object_data['reply-to-id'], 'correct' => $replyToId]);
1210                                 $object_data['reply-to-id'] = $replyToId;
1211                         }
1212                 }
1213
1214                 $object_data['published'] = JsonLD::fetchElement($object, 'as:published', '@value');
1215                 $object_data['updated'] = JsonLD::fetchElement($object, 'as:updated', '@value');
1216
1217                 if (empty($object_data['updated'])) {
1218                         $object_data['updated'] = $object_data['published'];
1219                 }
1220
1221                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
1222                         $object_data['published'] = $object_data['updated'];
1223                 }
1224
1225                 $actor = JsonLD::fetchElement($object, 'as:attributedTo', '@id');
1226                 if (empty($actor)) {
1227                         $actor = JsonLD::fetchElement($object, 'as:actor', '@id');
1228                 }
1229
1230                 $location = JsonLD::fetchElement($object, 'as:location', 'as:name', '@type', 'as:Place');
1231                 $location = JsonLD::fetchElement($location, 'location', '@value');
1232                 if ($location) {
1233                         // Some AP software allow formatted text in post location, so we run all the text converters we have to boil
1234                         // down to HTML and then finally format to plaintext.
1235                         $location = Markdown::convert($location);
1236                         $location = BBCode::convert($location);
1237                         $location = HTML::toPlaintext($location);
1238                 }
1239
1240                 $object_data['sc:identifier'] = JsonLD::fetchElement($object, 'sc:identifier', '@value');
1241                 $object_data['diaspora:guid'] = JsonLD::fetchElement($object, 'diaspora:guid', '@value');
1242                 $object_data['diaspora:comment'] = JsonLD::fetchElement($object, 'diaspora:comment', '@value');
1243                 $object_data['diaspora:like'] = JsonLD::fetchElement($object, 'diaspora:like', '@value');
1244                 $object_data['actor'] = $object_data['author'] = $actor;
1245                 $object_data['context'] = JsonLD::fetchElement($object, 'as:context', '@id');
1246                 $object_data['conversation'] = JsonLD::fetchElement($object, 'ostatus:conversation', '@id');
1247                 $object_data['sensitive'] = JsonLD::fetchElement($object, 'as:sensitive');
1248                 $object_data['name'] = JsonLD::fetchElement($object, 'as:name', '@value');
1249                 $object_data['summary'] = JsonLD::fetchElement($object, 'as:summary', '@value');
1250                 $object_data['content'] = JsonLD::fetchElement($object, 'as:content', '@value');
1251                 $object_data = self::getSource($object, $object_data);
1252                 $object_data['start-time'] = JsonLD::fetchElement($object, 'as:startTime', '@value');
1253                 $object_data['end-time'] = JsonLD::fetchElement($object, 'as:endTime', '@value');
1254                 $object_data['location'] = $location;
1255                 $object_data['latitude'] = JsonLD::fetchElement($object, 'as:location', 'as:latitude', '@type', 'as:Place');
1256                 $object_data['latitude'] = JsonLD::fetchElement($object_data, 'latitude', '@value');
1257                 $object_data['longitude'] = JsonLD::fetchElement($object, 'as:location', 'as:longitude', '@type', 'as:Place');
1258                 $object_data['longitude'] = JsonLD::fetchElement($object_data, 'longitude', '@value');
1259                 $object_data['attachments'] = self::processAttachments(JsonLD::fetchElementArray($object, 'as:attachment') ?? []);
1260                 $object_data['tags'] = self::processTags(JsonLD::fetchElementArray($object, 'as:tag') ?? []);
1261                 $object_data['emojis'] = self::processEmojis(JsonLD::fetchElementArray($object, 'as:tag', 'toot:Emoji') ?? []);
1262                 $object_data['generator'] = JsonLD::fetchElement($object, 'as:generator', 'as:name', '@type', 'as:Application');
1263                 $object_data['generator'] = JsonLD::fetchElement($object_data, 'generator', '@value');
1264                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'as:url', '@id');
1265
1266                 // Special treatment for Hubzilla links
1267                 if (is_array($object_data['alternate-url'])) {
1268                         $object_data['alternate-url'] = JsonLD::fetchElement($object_data['alternate-url'], 'as:href', '@id');
1269
1270                         if (!is_string($object_data['alternate-url'])) {
1271                                 $object_data['alternate-url'] = JsonLD::fetchElement($object['as:url'], 'as:href', '@id');
1272                         }
1273                 }
1274
1275                 if (in_array($object_data['object_type'], ['as:Audio', 'as:Video'])) {
1276                         $object_data = self::processAttachmentUrls($object, $object_data);
1277                 }
1278
1279                 $receiverdata = self::getReceivers($object, $object_data['actor'], $object_data['tags'], true);
1280                 $receivers = $reception_types = [];
1281                 foreach ($receiverdata as $key => $data) {
1282                         $receivers[$key] = $data['uid'];
1283                         $reception_types[$data['uid']] = $data['type'] ?? 0;
1284                 }
1285
1286                 $object_data['receiver'] = $receivers;
1287                 $object_data['reception_type'] = $reception_types;
1288
1289                 $object_data['unlisted'] = in_array(-1, $object_data['receiver']);
1290                 unset($object_data['receiver']['uid:-1']);
1291
1292                 // Common object data:
1293
1294                 // Unhandled
1295                 // @context, type, actor, signature, mediaType, duration, replies, icon
1296
1297                 // Also missing: (Defined in the standard, but currently unused)
1298                 // audience, preview, endTime, startTime, image
1299
1300                 // Data in Notes:
1301
1302                 // Unhandled
1303                 // contentMap, announcement_count, announcements, context_id, likes, like_count
1304                 // inReplyToStatusId, shares, quoteUrl, statusnetConversationId
1305
1306                 // Data in video:
1307
1308                 // To-Do?
1309                 // category, licence, language, commentsEnabled
1310
1311                 // Unhandled
1312                 // views, waitTranscoding, state, support, subtitleLanguage
1313                 // likes, dislikes, shares, comments
1314
1315                 return $object_data;
1316         }
1317 }