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