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                 $activity = json_decode($body, true);
  92                 if (empty($activity)) {
  93                         Logger::warning('Invalid body.');
  94                         return;
  95                 }
  96
  97                 $ldactivity = JsonLD::compact($activity);
  98
  99                 $actor = JsonLD::fetchElement($ldactivity, 'as:actor', '@id');
 100
 101                 $apcontact = APContact::getByURL($actor);
 102                 if (!empty($apcontact) && ($apcontact['type'] == 'Application') && ($apcontact['nick'] == 'relay')) {
 103                         self::processRelayPost($ldactivity, $actor);
 104                         return;
 105                 }
 106
 107                 $http_signer = HTTPSignature::getSigner($body, $header);
 108                 if (empty($http_signer)) {
 109                         Logger::warning('Invalid HTTP signature, message will be discarded.');
 110                         return;
 111                 } else {
 112                         Logger::info('Valid HTTP signature', ['signer' => $http_signer]);
 113                 }
 114
 115                 $signer = [$http_signer];
 116
 117                 Logger::info('Message for user ' . $uid . ' is from actor ' . $actor);
 118
 119                 if (LDSignature::isSigned($activity)) {
 120                         $ld_signer = LDSignature::getSigner($activity);
 121                         if (empty($ld_signer)) {
 122                                 Logger::log('Invalid JSON-LD signature from ' . $actor, Logger::DEBUG);
 123                         } elseif ($ld_signer != $http_signer) {
 124                                 $signer[] = $ld_signer;
 125                         }
 126                         if (!empty($ld_signer && ($actor == $http_signer))) {
 127                                 Logger::log('The HTTP and the JSON-LD signature belong to ' . $ld_signer, Logger::DEBUG);
 128                                 $trust_source = true;
 129                         } elseif (!empty($ld_signer)) {
 130                                 Logger::log('JSON-LD signature is signed by ' . $ld_signer, Logger::DEBUG);
 131                                 $trust_source = true;
 132                         } elseif ($actor == $http_signer) {
 133                                 Logger::log('Bad JSON-LD signature, but HTTP signer fits the actor.', Logger::DEBUG);
 134                                 $trust_source = true;
 135                         } else {
 136                                 Logger::log('Invalid JSON-LD signature and the HTTP signer is different.', Logger::DEBUG);
 137                                 $trust_source = false;
 138                         }
 139                 } elseif ($actor == $http_signer) {
 140                         Logger::log('Trusting post without JSON-LD signature, The actor fits the HTTP signer.', Logger::DEBUG);
 141                         $trust_source = true;
 142                 } else {
 143                         Logger::log('No JSON-LD signature, different actor.', Logger::DEBUG);
 144                         $trust_source = false;
 145                 }
 146
 147                 self::processActivity($ldactivity, $body, $uid, $trust_source, true, $signer);
 148         }
 149
 150         /**
 151          * Process incoming posts from relays
 152          *
 153          * @param array  $activity
 154          * @param string $actor
 155          * @return void
 156          */
 157         private static function processRelayPost(array $activity, string $actor)
 158         {
 159                 $type = JsonLD::fetchElement($activity, '@type');
 160                 if (!$type) {
 161                         Logger::info('Empty type', ['activity' => $activity]);
 162                         return;
 163                 }
 164
 165                 if ($type != 'as:Announce') {
 166                         Logger::info('Not an announcement', ['activity' => $activity]);
 167                         return;
 168                 }
 169
 170                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 171                 if (empty($object_id)) {
 172                         Logger::info('No object id found', ['activity' => $activity]);
 173                         return;
 174                 }
 175
 176                 Logger::info('Got relayed message id', ['id' => $object_id]);
 177
 178                 $item_id = Item::searchByLink($object_id);
 179                 if ($item_id) {
 180                         Logger::info('Relayed message already exists', ['id' => $object_id, 'item' => $item_id]);
 181                         return;
 182                 }
 183
 184                 $id = Processor::fetchMissingActivity($object_id, [], $actor);
 185                 if (empty($id)) {
 186                         Logger::notice('Relayed message had not been fetched', ['id' => $object_id]);
 187                         return;
 188                 }
 189
 190                 $item_id = Item::searchByLink($object_id);
 191                 if ($item_id) {
 192                         Logger::info('Relayed message had been fetched and stored', ['id' => $object_id, 'item' => $item_id]);
 193                 } else {
 194                         Logger::notice('Relayed message had not been stored', ['id' => $object_id]);
 195                 }
 196         }
 197
 198         /**
 199          * Fetches the object type for a given object id
 200          *
 201          * @param array   $activity
 202          * @param string  $object_id Object ID of the the provided object
 203          * @param integer $uid       User ID
 204          *
 205          * @return string with object type
 206          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 207          * @throws \ImagickException
 208          */
 209         private static function fetchObjectType($activity, $object_id, $uid = 0)
 210         {
 211                 if (!empty($activity['as:object'])) {
 212                         $object_type = JsonLD::fetchElement($activity['as:object'], '@type');
 213                         if (!empty($object_type)) {
 214                                 return $object_type;
 215                         }
 216                 }
 217
 218                 if (Item::exists(['uri' => $object_id, 'gravity' => [GRAVITY_PARENT, GRAVITY_COMMENT]])) {
 219                         // We just assume "note" since it doesn't make a difference for the further processing
 220                         return 'as:Note';
 221                 }
 222
 223                 $profile = APContact::getByURL($object_id);
 224                 if (!empty($profile['type'])) {
 225                         return 'as:' . $profile['type'];
 226                 }
 227
 228                 $data = ActivityPub::fetchContent($object_id, $uid);
 229                 if (!empty($data)) {
 230                         $object = JsonLD::compact($data);
 231                         $type = JsonLD::fetchElement($object, '@type');
 232                         if (!empty($type)) {
 233                                 return $type;
 234                         }
 235                 }
 236
 237                 return null;
 238         }
 239
 240         /**
 241          * Prepare the object array
 242          *
 243          * @param array   $activity     Array with activity data
 244          * @param integer $uid          User ID
 245          * @param boolean $push         Message had been pushed to our system
 246          * @param boolean $trust_source Do we trust the source?
 247          *
 248          * @return array with object data
 249          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 250          * @throws \ImagickException
 251          */
 252         public static function prepareObjectData($activity, $uid, $push, &$trust_source)
 253         {
 254                 $id = JsonLD::fetchElement($activity, '@id');
 255                 if (!empty($id) && !$trust_source) {
 256                         $fetched_activity = ActivityPub::fetchContent($id, $uid ?? 0);
 257                         if (!empty($fetched_activity)) {
 258                                 $object = JsonLD::compact($fetched_activity);
 259                                 $fetched_id = JsonLD::fetchElement($object, '@id');
 260                                 if ($fetched_id == $id) {
 261                                         Logger::info('Activity had been fetched successfully', ['id' => $id]);
 262                                         $trust_source = true;
 263                                         $activity = $object;
 264                                 } else {
 265                                         Logger::info('Activity id is not equal', ['id' => $id, 'fetched' => $fetched_id]);
 266                                 }
 267                         } else {
 268                                 Logger::info('Activity could not been fetched', ['id' => $id]);
 269                         }
 270                 }
 271
 272                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 273                 if (empty($actor)) {
 274                         Logger::info('Empty actor', ['activity' => $activity]);
 275                         return [];
 276                 }
 277
 278                 $type = JsonLD::fetchElement($activity, '@type');
 279
 280                 // Fetch all receivers from to, cc, bto and bcc
 281                 $receiverdata = self::getReceivers($activity, $actor);
 282                 $receivers = $reception_types = [];
 283                 foreach ($receiverdata as $key => $data) {
 284                         $receivers[$key] = $data['uid'];
 285                         $reception_types[$data['uid']] = $data['type'] ?? 0;
 286                 }
 287
 288                 // When it is a delivery to a personal inbox we add that user to the receivers
 289                 if (!empty($uid)) {
 290                         $additional = ['uid:' . $uid => $uid];
 291                         $receivers = array_merge($receivers, $additional);
 292                         if (empty($reception_types[$uid]) || in_array($reception_types[$uid], [self::TARGET_UNKNOWN, self::TARGET_FOLLOWER, self::TARGET_ANSWER, self::TARGET_GLOBAL])) {
 293                                 $reception_types[$uid] = self::TARGET_BCC;
 294                         }
 295                 } else {
 296                         // We possibly need some user to fetch private content,
 297                         // so we fetch the first out ot the list.
 298                         $uid = self::getFirstUserFromReceivers($receivers);
 299                 }
 300
 301                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 302                 if (empty($object_id)) {
 303                         Logger::log('No object found', Logger::DEBUG);
 304                         return [];
 305                 }
 306
 307                 if (!is_string($object_id)) {
 308                         Logger::info('Invalid object id', ['object' => $object_id]);
 309                         return [];
 310                 }
 311
 312                 $object_type = self::fetchObjectType($activity, $object_id, $uid);
 313
 314                 // Fetch the content only on activities where this matters
 315                 if (in_array($type, ['as:Create', 'as:Update', 'as:Announce'])) {
 316                         // Always fetch on "Announce"
 317                         $object_data = self::fetchObject($object_id, $activity['as:object'], $trust_source && ($type != 'as:Announce'), $uid);
 318                         if (empty($object_data)) {
 319                                 Logger::log("Object data couldn't be processed", Logger::DEBUG);
 320                                 return [];
 321                         }
 322
 323                         $object_data['object_id'] = $object_id;
 324
 325                         if ($type == 'as:Announce') {
 326                                 $object_data['push'] = false;
 327                         } else {
 328                                 $object_data['push'] = $push;
 329                         }
 330
 331                         // Test if it is an answer to a mail
 332                         if (DBA::exists('mail', ['uri' => $object_data['reply-to-id']])) {
 333                                 $object_data['directmessage'] = true;
 334                         } else {
 335                                 $object_data['directmessage'] = JsonLD::fetchElement($activity, 'litepub:directMessage');
 336                         }
 337                 } elseif (in_array($type, array_merge(self::ACTIVITY_TYPES, ['as:Follow'])) && in_array($object_type, self::CONTENT_TYPES)) {
 338                         // Create a mostly empty array out of the activity data (instead of the object).
 339                         // This way we later don't have to check for the existence of ech individual array element.
 340                         $object_data = self::processObject($activity);
 341                         $object_data['name'] = $type;
 342                         $object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 343                         $object_data['object_id'] = $object_id;
 344                         $object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
 345                 } elseif (in_array($type, ['as:Add'])) {
 346                         $object_data = [];
 347                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 348                         $object_data['target_id'] = JsonLD::fetchElement($activity, 'as:target', '@id');
 349                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 350                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 351                         $object_data['object_content'] = JsonLD::fetchElement($activity['as:object'], 'as:content', '@type');
 352                 } else {
 353                         $object_data = [];
 354                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 355                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 356                         $object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor', '@id');
 357                         $object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
 358                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 359
 360                         // An Undo is done on the object of an object, so we need that type as well
 361                         if (($type == 'as:Undo') && !empty($object_data['object_object'])) {
 362                                 $object_data['object_object_type'] = self::fetchObjectType([], $object_data['object_object'], $uid);
 363                         }
 364                 }
 365
 366                 $object_data = self::addActivityFields($object_data, $activity);
 367
 368                 if (empty($object_data['object_type'])) {
 369                         $object_data['object_type'] = $object_type;
 370                 }
 371
 372                 $object_data['type'] = $type;
 373                 $object_data['actor'] = $actor;
 374                 $object_data['item_receiver'] = $receivers;
 375                 $object_data['receiver'] = array_merge($object_data['receiver'] ?? [], $receivers);
 376                 $object_data['reception_type'] = array_merge($object_data['reception_type'] ?? [], $reception_types);
 377
 378                 $author = $object_data['author'] ?? $actor;
 379                 if (!empty($author) && !empty($object_data['id'])) {
 380                         $author_host = parse_url($author, PHP_URL_HOST);
 381                         $id_host = parse_url($object_data['id'], PHP_URL_HOST);
 382                         if ($author_host == $id_host) {
 383                                 Logger::info('Valid hosts', ['type' => $type, 'host' => $id_host]);
 384                         } else {
 385                                 Logger::notice('Differing hosts on author and id', ['type' => $type, 'author' => $author_host, 'id' => $id_host]);
 386                                 $trust_source = false;
 387                         }
 388                 }
 389
 390                 Logger::log('Processing ' . $object_data['type'] . ' ' . $object_data['object_type'] . ' ' . $object_data['id'], Logger::DEBUG);
 391
 392                 return $object_data;
 393         }
 394
 395         /**
 396          * Fetches the first user id from the receiver array
 397          *
 398          * @param array $receivers Array with receivers
 399          * @return integer user id;
 400          */
 401         public static function getFirstUserFromReceivers($receivers)
 402         {
 403                 foreach ($receivers as $receiver) {
 404                         if (!empty($receiver)) {
 405                                 return $receiver;
 406                         }
 407                 }
 408                 return 0;
 409         }
 410
 411         /**
 412          * Processes the activity object
 413          *
 414          * @param array   $activity     Array with activity data
 415          * @param string  $body
 416          * @param integer $uid          User ID
 417          * @param boolean $trust_source Do we trust the source?
 418          * @param boolean $push         Message had been pushed to our system
 419          * @throws \Exception
 420          */
 421         public static function processActivity($activity, string $body = '', int $uid = null, bool $trust_source = false, bool $push = false, array $signer = [])
 422         {
 423                 $type = JsonLD::fetchElement($activity, '@type');
 424                 if (!$type) {
 425                         Logger::info('Empty type', ['activity' => $activity]);
 426                         return;
 427                 }
 428
 429                 if (!JsonLD::fetchElement($activity, 'as:object', '@id')) {
 430                         Logger::info('Empty object', ['activity' => $activity]);
 431                         return;
 432                 }
 433
 434                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 435                 if (empty($actor)) {
 436                         Logger::info('Empty actor', ['activity' => $activity]);
 437                         return;
 438                 }
 439
 440                 if (is_array($activity['as:object'])) {
 441                         $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
 442                 } else {
 443                         $attributed_to = '';
 444                 }
 445
 446                 // Test the provided signatures against the actor and "attributedTo"
 447                 if ($trust_source) {
 448                         if (!empty($attributed_to) && !empty($actor)) {
 449                                 $trust_source = (in_array($actor, $signer) && in_array($attributed_to, $signer));
 450                         } else {
 451                                 $trust_source = in_array($actor, $signer);
 452                         }
 453                 }
 454
 455                 // $trust_source is called by reference and is set to true if the content was retrieved successfully
 456                 $object_data = self::prepareObjectData($activity, $uid, $push, $trust_source);
 457                 if (empty($object_data)) {
 458                         Logger::info('No object data found', ['activity' => $activity]);
 459                         return;
 460                 }
 461
 462                 if (!$trust_source) {
 463                         Logger::info('Activity trust could not be achieved.',  ['id' => $object_data['object_id'], 'type' => $type, 'signer' => $signer, 'actor' => $actor, 'attributedTo' => $attributed_to]);
 464                         return;
 465                 }
 466
 467                 if (!empty($body) && empty($object_data['raw'])) {
 468                         $object_data['raw'] = $body;
 469                 }
 470
 471                 // Internal flag for thread completion. See Processor.php
 472                 if (!empty($activity['thread-completion'])) {
 473                         $object_data['thread-completion'] = $activity['thread-completion'];
 474                 }
 475
 476                 // Internal flag for posts that arrived via relay
 477                 if (!empty($activity['from-relay'])) {
 478                         $object_data['from-relay'] = $activity['from-relay'];
 479                 }
 480
 481                 switch ($type) {
 482                         case 'as:Create':
 483                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 484                                         $item = ActivityPub\Processor::createItem($object_data);
 485                                         ActivityPub\Processor::postItem($object_data, $item);
 486                                 }
 487                                 break;
 488
 489                         case 'as:Add':
 490                                 if ($object_data['object_type'] == 'as:tag') {
 491                                         ActivityPub\Processor::addTag($object_data);
 492                                 }
 493                                 break;
 494
 495                         case 'as:Announce':
 496                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 497                                         $object_data['thread-completion'] = true;
 498
 499                                         $item = ActivityPub\Processor::createItem($object_data);
 500                                         if (empty($item)) {
 501                                                 return;
 502                                         }
 503
 504                                         $item['post-type'] = Item::PT_ANNOUNCEMENT;
 505                                         ActivityPub\Processor::postItem($object_data, $item);
 506
 507                                         $announce_object_data = self::processObject($activity);
 508                                         $announce_object_data['name'] = $type;
 509                                         $announce_object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 510                                         $announce_object_data['object_id'] = $object_data['object_id'];
 511                                         $announce_object_data['object_type'] = $object_data['object_type'];
 512                                         $announce_object_data['push'] = $push;
 513
 514                                         if (!empty($body)) {
 515                                                 $announce_object_data['raw'] = $body;
 516                                         }
 517
 518                                         ActivityPub\Processor::createActivity($announce_object_data, Activity::ANNOUNCE);
 519                                 }
 520                                 break;
 521
 522                         case 'as:Like':
 523                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 524                                         ActivityPub\Processor::createActivity($object_data, Activity::LIKE);
 525                                 }
 526                                 break;
 527
 528                         case 'as:Dislike':
 529                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 530                                         ActivityPub\Processor::createActivity($object_data, Activity::DISLIKE);
 531                                 }
 532                                 break;
 533
 534                         case 'as:TentativeAccept':
 535                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 536                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDMAYBE);
 537                                 }
 538                                 break;
 539
 540                         case 'as:Update':
 541                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 542                                         ActivityPub\Processor::updateItem($object_data);
 543                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 544                                         ActivityPub\Processor::updatePerson($object_data);
 545                                 }
 546                                 break;
 547
 548                         case 'as:Delete':
 549                                 if ($object_data['object_type'] == 'as:Tombstone') {
 550                                         ActivityPub\Processor::deleteItem($object_data);
 551                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 552                                         ActivityPub\Processor::deletePerson($object_data);
 553                                 }
 554                                 break;
 555
 556                         case 'as:Follow':
 557                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 558                                         ActivityPub\Processor::followUser($object_data);
 559                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 560                                         $object_data['reply-to-id'] = $object_data['object_id'];
 561                                         ActivityPub\Processor::createActivity($object_data, Activity::FOLLOW);
 562                                 }
 563                                 break;
 564
 565                         case 'as:Accept':
 566                                 if ($object_data['object_type'] == 'as:Follow') {
 567                                         ActivityPub\Processor::acceptFollowUser($object_data);
 568                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 569                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTEND);
 570                                 }
 571                                 break;
 572
 573                         case 'as:Reject':
 574                                 if ($object_data['object_type'] == 'as:Follow') {
 575                                         ActivityPub\Processor::rejectFollowUser($object_data);
 576                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 577                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDNO);
 578                                 }
 579                                 break;
 580
 581                         case 'as:Undo':
 582                                 if (($object_data['object_type'] == 'as:Follow') &&
 583                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 584                                         ActivityPub\Processor::undoFollowUser($object_data);
 585                                 } elseif (($object_data['object_type'] == 'as:Accept') &&
 586                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 587                                         ActivityPub\Processor::rejectFollowUser($object_data);
 588                                 } elseif (in_array($object_data['object_type'], self::ACTIVITY_TYPES) &&
 589                                         in_array($object_data['object_object_type'], self::CONTENT_TYPES)) {
 590                                         ActivityPub\Processor::undoActivity($object_data);
 591                                 }
 592                                 break;
 593
 594                         default:
 595                                 Logger::log('Unknown activity: ' . $type . ' ' . $object_data['object_type'], Logger::DEBUG);
 596                                 break;
 597                 }
 598         }
 599
 600         /**
 601          * Fetch the receiver list from an activity array
 602          *
 603          * @param array   $activity
 604          * @param string  $actor
 605          * @param array   $tags
 606          * @param boolean $fetch_unlisted
 607          *
 608          * @return array with receivers (user id)
 609          * @throws \Exception
 610          */
 611         private static function getReceivers($activity, $actor, $tags = [], $fetch_unlisted = false)
 612         {
 613                 $reply = $receivers = [];
 614
 615                 // When it is an answer, we inherite the receivers from the parent
 616                 $replyto = JsonLD::fetchElement($activity, 'as:inReplyTo', '@id');
 617                 if (!empty($replyto)) {
 618                         $reply = [$replyto];
 619
 620                         // Fix possibly wrong item URI (could be an answer to a plink uri)
 621                         $fixedReplyTo = Item::getURIByLink($replyto);
 622                         if (!empty($fixedReplyTo)) {
 623                                 $reply[] = $fixedReplyTo;
 624                         }
 625                 }
 626
 627                 // Fetch all posts that refer to the object id
 628                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 629                 if (!empty($object_id)) {
 630                         $reply[] = $object_id;
 631                 }
 632
 633                 if (!empty($reply)) {
 634                         $parents = Item::select(['uid'], ['uri' => $reply]);
 635                         while ($parent = Item::fetch($parents)) {
 636                                 $receivers['uid:' . $parent['uid']] = ['uid' => $parent['uid'], 'type' => self::TARGET_ANSWER];
 637                         }
 638                 }
 639
 640                 if (!empty($actor)) {
 641                         $profile = APContact::getByURL($actor);
 642                         $followers = $profile['followers'] ?? '';
 643
 644                         Logger::log('Actor: ' . $actor . ' - Followers: ' . $followers, Logger::DEBUG);
 645                 } else {
 646                         Logger::info('Empty actor', ['activity' => $activity]);
 647                         $followers = '';
 648                 }
 649
 650                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
 651                         $receiver_list = JsonLD::fetchElementArray($activity, $element, '@id');
 652                         if (empty($receiver_list)) {
 653                                 continue;
 654                         }
 655
 656                         foreach ($receiver_list as $receiver) {
 657                                 if ($receiver == self::PUBLIC_COLLECTION) {
 658                                         $receivers['uid:0'] = ['uid' => 0, 'type' => self::TARGET_GLOBAL];
 659                                 }
 660
 661                                 // Add receiver "-1" for unlisted posts
 662                                 if ($fetch_unlisted && ($receiver == self::PUBLIC_COLLECTION) && ($element == 'as:cc')) {
 663                                         $receivers['uid:-1'] = ['uid' => -1, 'type' => self::TARGET_GLOBAL];
 664                                 }
 665
 666                                 // Fetch the receivers for the public and the followers collection
 667                                 if (in_array($receiver, [$followers, self::PUBLIC_COLLECTION]) && !empty($actor)) {
 668                                         $receivers = self::getReceiverForActor($actor, $tags, $receivers);
 669                                         continue;
 670                                 }
 671
 672                                 // Fetching all directly addressed receivers
 673                                 $condition = ['self' => true, 'nurl' => Strings::normaliseLink($receiver)];
 674                                 $contact = DBA::selectFirst('contact', ['uid', 'contact-type'], $condition);
 675                                 if (!DBA::isResult($contact)) {
 676                                         continue;
 677                                 }
 678
 679                                 // Check if the potential receiver is following the actor
 680                                 // Exception: The receiver is targetted via "to" or this is a comment
 681                                 if ((($element != 'as:to') && empty($replyto)) || ($contact['contact-type'] == Contact::TYPE_COMMUNITY)) {
 682                                         $networks = Protocol::FEDERATED;
 683                                         $condition = ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
 684                                                 'network' => $networks, 'archive' => false, 'pending' => false, 'uid' => $contact['uid']];
 685
 686                                         // Forum posts are only accepted from forum contacts
 687                                         if ($contact['contact-type'] == Contact::TYPE_COMMUNITY) {
 688                                                 $condition['rel'] = [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER];
 689                                         }
 690
 691                                         if (!DBA::exists('contact', $condition)) {
 692                                                 continue;
 693                                         }
 694                                 }
 695
 696                                 $type = $receivers['uid:' . $contact['uid']]['type'] ?? self::TARGET_UNKNOWN;
 697                                 if (in_array($type, [self::TARGET_UNKNOWN, self::TARGET_FOLLOWER, self::TARGET_ANSWER, self::TARGET_GLOBAL])) {
 698                                         switch ($element) {
 699                                                 case 'as:to':
 700                                                         $type = self::TARGET_TO;
 701                                                         break;
 702                                                 case 'as:cc':
 703                                                         $type = self::TARGET_CC;
 704                                                         break;
 705                                                 case 'as:bto':
 706                                                         $type = self::TARGET_BTO;
 707                                                         break;
 708                                                 case 'as:bcc':
 709                                                         $type = self::TARGET_BCC;
 710                                                         break;
 711                                         }
 712
 713                                         $receivers['uid:' . $contact['uid']] = ['uid' => $contact['uid'], 'type' => $type];
 714                                 }
 715                         }
 716                 }
 717
 718                 self::switchContacts($receivers, $actor);
 719
 720                 return $receivers;
 721         }
 722
 723         /**
 724          * Fetch the receiver list of a given actor
 725          *
 726          * @param string $actor
 727          * @param array  $tags
 728          *
 729          * @return array with receivers (user id)
 730          * @throws \Exception
 731          */
 732         private static function getReceiverForActor($actor, $tags, $receivers)
 733         {
 734                 $basecondition = ['rel' => [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER],
 735                         'network' => Protocol::FEDERATED, 'archive' => false, 'pending' => false];
 736
 737                 $condition = DBA::mergeConditions($basecondition, ["`nurl` = ? AND `uid` != ?", Strings::normaliseLink($actor), 0]);
 738                 $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
 739                 while ($contact = DBA::fetch($contacts)) {
 740                         if (empty($receivers['uid:' . $contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
 741                                 $receivers['uid:' . $contact['uid']] = ['uid' => $contact['uid'], 'type' => self::TARGET_FOLLOWER];
 742                         }
 743                 }
 744                 DBA::close($contacts);
 745
 746                 // The queries are split because of performance issues
 747                 $condition = DBA::mergeConditions($basecondition, ["`alias` IN (?, ?) AND `uid` != ?", Strings::normaliseLink($actor), $actor, 0]);
 748                 $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
 749                 while ($contact = DBA::fetch($contacts)) {
 750                         if (empty($receivers['uid:' . $contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
 751                                 $receivers['uid:' . $contact['uid']] = ['uid' => $contact['uid'], 'type' => self::TARGET_FOLLOWER];
 752                         }
 753                 }
 754                 DBA::close($contacts);
 755                 return $receivers;
 756         }
 757
 758         /**
 759          * Tests if the contact is a valid receiver for this actor
 760          *
 761          * @param array  $contact
 762          * @param string $actor
 763          * @param array  $tags
 764          *
 765          * @return bool with receivers (user id)
 766          * @throws \Exception
 767          */
 768         private static function isValidReceiverForActor($contact, $tags)
 769         {
 770                 // Are we following the contact? Then this is a valid receiver
 771                 if (in_array($contact['rel'], [Contact::SHARING, Contact::FRIEND])) {
 772                         return true;
 773                 }
 774
 775                 // When the possible receiver isn't a community, then it is no valid receiver
 776                 $owner = User::getOwnerDataById($contact['uid']);
 777                 if (empty($owner) || ($owner['contact-type'] != Contact::TYPE_COMMUNITY)) {
 778                         return false;
 779                 }
 780
 781                 // Is the community account tagged?
 782                 foreach ($tags as $tag) {
 783                         if ($tag['type'] != 'Mention') {
 784                                 continue;
 785                         }
 786
 787                         if (Strings::compareLink($tag['href'], $owner['url'])) {
 788                                 return true;
 789                         }
 790                 }
 791
 792                 return false;
 793         }
 794
 795         /**
 796          * Switches existing contacts to ActivityPub
 797          *
 798          * @param integer $cid Contact ID
 799          * @param integer $uid User ID
 800          * @param string  $url Profile URL
 801          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 802          * @throws \ImagickException
 803          */
 804         public static function switchContact($cid, $uid, $url)
 805         {
 806                 if (DBA::exists('contact', ['id' => $cid, 'network' => Protocol::ACTIVITYPUB])) {
 807                         Logger::info('Contact is already ActivityPub', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
 808                         return;
 809                 }
 810
 811                 if (Contact::updateFromProbe($cid)) {
 812                         Logger::info('Update was successful', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
 813                 }
 814
 815                 // Send a new follow request to be sure that the connection still exists
 816                 if (($uid != 0) && DBA::exists('contact', ['id' => $cid, 'rel' => [Contact::SHARING, Contact::FRIEND], 'network' => Protocol::ACTIVITYPUB])) {
 817                         Logger::info('Contact had been switched to ActivityPub. Sending a new follow request.', ['uid' => $uid, 'url' => $url]);
 818                         ActivityPub\Transmitter::sendActivity('Follow', $url, $uid);
 819                 }
 820         }
 821
 822         /**
 823          *
 824          *
 825          * @param $receivers
 826          * @param $actor
 827          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 828          * @throws \ImagickException
 829          */
 830         private static function switchContacts($receivers, $actor)
 831         {
 832                 if (empty($actor)) {
 833                         return;
 834                 }
 835
 836                 foreach ($receivers as $receiver) {
 837                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver['uid'], 'network' => Protocol::OSTATUS, 'nurl' => Strings::normaliseLink($actor)]);
 838                         if (DBA::isResult($contact)) {
 839                                 self::switchContact($contact['id'], $receiver['uid'], $actor);
 840                         }
 841
 842                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver['uid'], 'network' => Protocol::OSTATUS, 'alias' => [Strings::normaliseLink($actor), $actor]]);
 843                         if (DBA::isResult($contact)) {
 844                                 self::switchContact($contact['id'], $receiver['uid'], $actor);
 845                         }
 846                 }
 847         }
 848
 849         /**
 850          *
 851          *
 852          * @param       $object_data
 853          * @param array $activity
 854          *
 855          * @return mixed
 856          */
 857         private static function addActivityFields($object_data, $activity)
 858         {
 859                 if (!empty($activity['published']) && empty($object_data['published'])) {
 860                         $object_data['published'] = JsonLD::fetchElement($activity, 'as:published', '@value');
 861                 }
 862
 863                 if (!empty($activity['diaspora:guid']) && empty($object_data['diaspora:guid'])) {
 864                         $object_data['diaspora:guid'] = JsonLD::fetchElement($activity, 'diaspora:guid', '@value');
 865                 }
 866
 867                 $object_data['service'] = JsonLD::fetchElement($activity, 'as:instrument', 'as:name', '@type', 'as:Service');
 868                 $object_data['service'] = JsonLD::fetchElement($object_data, 'service', '@value');
 869
 870                 if (!empty($object_data['object_id'])) {
 871                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
 872                         $objectId = Item::getURIByLink($object_data['object_id']);
 873                         if (!empty($objectId) && ($object_data['object_id'] != $objectId)) {
 874                                 Logger::notice('Fix wrong object-id', ['received' => $object_data['object_id'], 'correct' => $objectId]);
 875                                 $object_data['object_id'] = $objectId;
 876                         }
 877                 }
 878
 879                 return $object_data;
 880         }
 881
 882         /**
 883          * Fetches the object data from external ressources if needed
 884          *
 885          * @param string  $object_id    Object ID of the the provided object
 886          * @param array   $object       The provided object array
 887          * @param boolean $trust_source Do we trust the provided object?
 888          * @param integer $uid          User ID for the signature that we use to fetch data
 889          *
 890          * @return array|false with trusted and valid object data
 891          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 892          * @throws \ImagickException
 893          */
 894         private static function fetchObject(string $object_id, array $object = [], bool $trust_source = false, int $uid = 0)
 895         {
 896                 // By fetching the type we check if the object is complete.
 897                 $type = JsonLD::fetchElement($object, '@type');
 898
 899                 if (!$trust_source || empty($type)) {
 900                         $data = ActivityPub::fetchContent($object_id, $uid);
 901                         if (!empty($data)) {
 902                                 $object = JsonLD::compact($data);
 903                                 Logger::log('Fetched content for ' . $object_id, Logger::DEBUG);
 904                         } else {
 905                                 Logger::log('Empty content for ' . $object_id . ', check if content is available locally.', Logger::DEBUG);
 906
 907                                 $item = Item::selectFirst([], ['uri' => $object_id]);
 908                                 if (!DBA::isResult($item)) {
 909                                         Logger::log('Object with url ' . $object_id . ' was not found locally.', Logger::DEBUG);
 910                                         return false;
 911                                 }
 912                                 Logger::log('Using already stored item for url ' . $object_id, Logger::DEBUG);
 913                                 $data = ActivityPub\Transmitter::createNote($item);
 914                                 $object = JsonLD::compact($data);
 915                         }
 916
 917                         $id = JsonLD::fetchElement($object, '@id');
 918                         if (empty($id)) {
 919                                 Logger::info('Empty id');
 920                                 return false;
 921                         }
 922
 923                         if ($id != $object_id) {
 924                                 Logger::info('Fetched id differs from provided id', ['provided' => $object_id, 'fetched' => $id]);
 925                                 return false;
 926                         }
 927                 } else {
 928                         Logger::log('Using original object for url ' . $object_id, Logger::DEBUG);
 929                 }
 930
 931                 $type = JsonLD::fetchElement($object, '@type');
 932                 if (empty($type)) {
 933                         Logger::info('Empty type');
 934                         return false;
 935                 }
 936
 937                 // We currently don't handle 'pt:CacheFile', but with this step we avoid logging
 938                 if (in_array($type, self::CONTENT_TYPES) || ($type == 'pt:CacheFile')) {
 939                         $object_data = self::processObject($object);
 940
 941                         if (!empty($data)) {
 942                                 $object_data['raw'] = json_encode($data);
 943                         }
 944                         return $object_data;
 945                 }
 946
 947                 if ($type == 'as:Announce') {
 948                         $object_id = JsonLD::fetchElement($object, 'object', '@id');
 949                         if (empty($object_id) || !is_string($object_id)) {
 950                                 return false;
 951                         }
 952                         return self::fetchObject($object_id, [], false, $uid);
 953                 }
 954
 955                 Logger::log('Unhandled object type: ' . $type, Logger::DEBUG);
 956                 return false;
 957         }
 958
 959         /**
 960          * Convert tags from JSON-LD format into a simplified format
 961          *
 962          * @param array $tags Tags in JSON-LD format
 963          *
 964          * @return array with tags in a simplified format
 965          */
 966         public static function processTags(array $tags)
 967         {
 968                 $taglist = [];
 969
 970                 foreach ($tags as $tag) {
 971                         if (empty($tag)) {
 972                                 continue;
 973                         }
 974
 975                         $element = ['type' => str_replace('as:', '', JsonLD::fetchElement($tag, '@type')),
 976                                 'href' => JsonLD::fetchElement($tag, 'as:href', '@id'),
 977                                 'name' => JsonLD::fetchElement($tag, 'as:name', '@value')];
 978
 979                         if (empty($element['type'])) {
 980                                 continue;
 981                         }
 982
 983                         if (empty($element['href'])) {
 984                                 $element['href'] = $element['name'];
 985                         }
 986
 987                         $taglist[] = $element;
 988                 }
 989                 return $taglist;
 990         }
 991
 992         /**
 993          * Convert emojis from JSON-LD format into a simplified format
 994          *
 995          * @param array $emojis
 996          * @return array with emojis in a simplified format
 997          */
 998         private static function processEmojis(array $emojis)
 999         {
1000                 $emojilist = [];
1001
1002                 foreach ($emojis as $emoji) {
1003                         if (empty($emoji) || (JsonLD::fetchElement($emoji, '@type') != 'toot:Emoji') || empty($emoji['as:icon'])) {
1004                                 continue;
1005                         }
1006
1007                         $url = JsonLD::fetchElement($emoji['as:icon'], 'as:url', '@id');
1008                         $element = ['name' => JsonLD::fetchElement($emoji, 'as:name', '@value'),
1009                                 'href' => $url];
1010
1011                         $emojilist[] = $element;
1012                 }
1013
1014                 return $emojilist;
1015         }
1016
1017         /**
1018          * Convert attachments from JSON-LD format into a simplified format
1019          *
1020          * @param array $attachments Attachments in JSON-LD format
1021          *
1022          * @return array Attachments in a simplified format
1023          */
1024         private static function processAttachments(array $attachments)
1025         {
1026                 $attachlist = [];
1027
1028                 // Removes empty values
1029                 $attachments = array_filter($attachments);
1030
1031                 foreach ($attachments as $attachment) {
1032                         switch (JsonLD::fetchElement($attachment, '@type')) {
1033                                 case 'as:Page':
1034                                         $pageUrl = null;
1035                                         $pageImage = null;
1036
1037                                         $urls = JsonLD::fetchElementArray($attachment, 'as:url');
1038                                         foreach ($urls as $url) {
1039                                                 // Single scalar URL case
1040                                                 if (is_string($url)) {
1041                                                         $pageUrl = $url;
1042                                                         continue;
1043                                                 }
1044
1045                                                 $href = JsonLD::fetchElement($url, 'as:href', '@id');
1046                                                 $mediaType = JsonLD::fetchElement($url, 'as:mediaType', '@value');
1047                                                 if (Strings::startsWith($mediaType, 'image')) {
1048                                                         $pageImage = $href;
1049                                                 } else {
1050                                                         $pageUrl = $href;
1051                                                 }
1052                                         }
1053
1054                                         $attachlist[] = [
1055                                                 'type'  => 'link',
1056                                                 'title' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1057                                                 'desc'  => JsonLD::fetchElement($attachment, 'as:summary', '@value'),
1058                                                 'url'   => $pageUrl,
1059                                                 'image' => $pageImage,
1060                                         ];
1061                                         break;
1062                                 case 'as:Link':
1063                                         $attachlist[] = [
1064                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1065                                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType', '@value'),
1066                                                 'name' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1067                                                 'url' => JsonLD::fetchElement($attachment, 'as:href', '@id')
1068                                         ];
1069                                         break;
1070                                 case 'as:Image':
1071                                         $mediaType = JsonLD::fetchElement($attachment, 'as:mediaType', '@value');
1072                                         $imageFullUrl = JsonLD::fetchElement($attachment, 'as:url', '@id');
1073                                         $imagePreviewUrl = null;
1074                                         // Multiple URLs?
1075                                         if (!$imageFullUrl && ($urls = JsonLD::fetchElementArray($attachment, 'as:url'))) {
1076                                                 $imageVariants = [];
1077                                                 $previewVariants = [];
1078                                                 foreach ($urls as $url) {
1079                                                         // Scalar URL, no discrimination possible
1080                                                         if (is_string($url)) {
1081                                                                 $imageFullUrl = $url;
1082                                                                 continue;
1083                                                         }
1084
1085                                                         // Not sure what to do with a different Link media type than the base Image, we skip
1086                                                         if ($mediaType != JsonLD::fetchElement($url, 'as:mediaType', '@value')) {
1087                                                                 continue;
1088                                                         }
1089
1090                                                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1091
1092                                                         // Default URL choice if no discriminating width is provided
1093                                                         $imageFullUrl = $href ?? $imageFullUrl;
1094
1095                                                         $width = intval(JsonLD::fetchElement($url, 'as:width', '@value') ?? 1);
1096
1097                                                         if ($href && $width) {
1098                                                                 $imageVariants[$width] = $href;
1099                                                                 // 632 is the ideal width for full screen frio posts, we compute the absolute distance to it
1100                                                                 $previewVariants[abs(632 - $width)] = $href;
1101                                                         }
1102                                                 }
1103
1104                                                 if ($imageVariants) {
1105                                                         // Taking the maximum size image
1106                                                         ksort($imageVariants);
1107                                                         $imageFullUrl = array_pop($imageVariants);
1108
1109                                                         // Taking the minimum number distance to the target distance
1110                                                         ksort($previewVariants);
1111                                                         $imagePreviewUrl = array_shift($previewVariants);
1112                                                 }
1113
1114                                                 unset($imageVariants);
1115                                                 unset($previewVariants);
1116                                         }
1117
1118                                         $attachlist[] = [
1119                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1120                                                 'mediaType' => $mediaType,
1121                                                 'name'  => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1122                                                 'url'   => $imageFullUrl,
1123                                                 'image' => $imagePreviewUrl !== $imageFullUrl ? $imagePreviewUrl : null,
1124                                         ];
1125                                         break;
1126                                 default:
1127                                         $attachlist[] = [
1128                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1129                                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType', '@value'),
1130                                                 'name' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1131                                                 'url' => JsonLD::fetchElement($attachment, 'as:url', '@id')
1132                                         ];
1133                         }
1134                 }
1135
1136                 return $attachlist;
1137         }
1138
1139         /**
1140          * Fetch the original source or content with the "language" Markdown or HTML
1141          *
1142          * @param array $object
1143          * @param array $object_data
1144          *
1145          * @return array
1146          * @throws \Exception
1147          */
1148         private static function getSource($object, $object_data)
1149         {
1150                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/bbcode');
1151                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1152                 if (!empty($object_data['source'])) {
1153                         return $object_data;
1154                 }
1155
1156                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/markdown');
1157                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1158                 if (!empty($object_data['source'])) {
1159                         $object_data['source'] = Markdown::toBBCode($object_data['source']);
1160                         return $object_data;
1161                 }
1162
1163                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/html');
1164                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1165                 if (!empty($object_data['source'])) {
1166                         $object_data['source'] = HTML::toBBCode($object_data['source']);
1167                         return $object_data;
1168                 }
1169
1170                 return $object_data;
1171         }
1172
1173         /**
1174          * Check if the "as:url" element is an array with multiple links
1175          * This is the case with audio and video posts.
1176          * Then the links are added as attachments
1177          *
1178          * @param array $object      The raw object
1179          * @param array $object_data The parsed object data for later processing
1180          * @return array the object data
1181          */
1182         private static function processAttachmentUrls(array $object, array $object_data) {
1183                 // Check if this is some url with multiple links
1184                 if (empty($object['as:url'])) {
1185                         return $object_data;
1186                 }
1187
1188                 $urls = $object['as:url'];
1189                 $keys = array_keys($urls);
1190                 if (!is_numeric(array_pop($keys))) {
1191                         return $object_data;
1192                 }
1193
1194                 $attachments = [];
1195
1196                 foreach ($urls as $url) {
1197                         if (empty($url['@type']) || ($url['@type'] != 'as:Link')) {
1198                                 continue;
1199                         }
1200
1201                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1202                         if (empty($href)) {
1203                                 continue;
1204                         }
1205
1206                         $mediatype = JsonLD::fetchElement($url, 'as:mediaType');
1207                         if (empty($mediatype)) {
1208                                 continue;
1209                         }
1210
1211                         if ($mediatype == 'text/html') {
1212                                 $object_data['alternate-url'] = $href;
1213                         }
1214
1215                         $filetype = strtolower(substr($mediatype, 0, strpos($mediatype, '/')));
1216
1217                         if ($filetype == 'audio') {
1218                                 $attachments[$filetype] = ['type' => $mediatype, 'url' => $href];
1219                         } elseif ($filetype == 'video') {
1220                                 $height = (int)JsonLD::fetchElement($url, 'as:height', '@value');
1221
1222                                 // We save bandwidth by using a moderate height
1223                                 // Peertube normally uses these heights: 240, 360, 480, 720, 1080
1224                                 if (!empty($attachments[$filetype]['height']) &&
1225                                         (($height > 480) || $height < $attachments[$filetype]['height'])) {
1226                                         continue;
1227                                 }
1228
1229                                 $attachments[$filetype] = ['type' => $mediatype, 'url' => $href, 'height' => $height];
1230                         }
1231                 }
1232
1233                 foreach ($attachments as $type => $attachment) {
1234                         $object_data['attachments'][] = ['type' => $type,
1235                                 'mediaType' => $attachment['type'],
1236                                 'name' => '',
1237                                 'url' => $attachment['url']];
1238                 }
1239                 return $object_data;
1240         }
1241
1242         /**
1243          * Fetches data from the object part of an activity
1244          *
1245          * @param array $object
1246          *
1247          * @return array
1248          * @throws \Exception
1249          */
1250         private static function processObject($object)
1251         {
1252                 if (!JsonLD::fetchElement($object, '@id')) {
1253                         return false;
1254                 }
1255
1256                 $object_data = [];
1257                 $object_data['object_type'] = JsonLD::fetchElement($object, '@type');
1258                 $object_data['id'] = JsonLD::fetchElement($object, '@id');
1259                 $object_data['reply-to-id'] = JsonLD::fetchElement($object, 'as:inReplyTo', '@id');
1260
1261                 // An empty "id" field is translated to "./" by the compactor, so we have to check for this content
1262                 if (empty($object_data['reply-to-id']) || ($object_data['reply-to-id'] == './')) {
1263                         $object_data['reply-to-id'] = $object_data['id'];
1264                 } else {
1265                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
1266                         $replyToId = Item::getURIByLink($object_data['reply-to-id']);
1267                         if (!empty($replyToId) && ($object_data['reply-to-id'] != $replyToId)) {
1268                                 Logger::notice('Fix wrong reply-to', ['received' => $object_data['reply-to-id'], 'correct' => $replyToId]);
1269                                 $object_data['reply-to-id'] = $replyToId;
1270                         }
1271                 }
1272
1273                 $object_data['published'] = JsonLD::fetchElement($object, 'as:published', '@value');
1274                 $object_data['updated'] = JsonLD::fetchElement($object, 'as:updated', '@value');
1275
1276                 if (empty($object_data['updated'])) {
1277                         $object_data['updated'] = $object_data['published'];
1278                 }
1279
1280                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
1281                         $object_data['published'] = $object_data['updated'];
1282                 }
1283
1284                 $actor = JsonLD::fetchElement($object, 'as:attributedTo', '@id');
1285                 if (empty($actor)) {
1286                         $actor = JsonLD::fetchElement($object, 'as:actor', '@id');
1287                 }
1288
1289                 $location = JsonLD::fetchElement($object, 'as:location', 'as:name', '@type', 'as:Place');
1290                 $location = JsonLD::fetchElement($location, 'location', '@value');
1291                 if ($location) {
1292                         // Some AP software allow formatted text in post location, so we run all the text converters we have to boil
1293                         // down to HTML and then finally format to plaintext.
1294                         $location = Markdown::convert($location);
1295                         $location = BBCode::convert($location);
1296                         $location = HTML::toPlaintext($location);
1297                 }
1298
1299                 $object_data['sc:identifier'] = JsonLD::fetchElement($object, 'sc:identifier', '@value');
1300                 $object_data['diaspora:guid'] = JsonLD::fetchElement($object, 'diaspora:guid', '@value');
1301                 $object_data['diaspora:comment'] = JsonLD::fetchElement($object, 'diaspora:comment', '@value');
1302                 $object_data['diaspora:like'] = JsonLD::fetchElement($object, 'diaspora:like', '@value');
1303                 $object_data['actor'] = $object_data['author'] = $actor;
1304                 $object_data['context'] = JsonLD::fetchElement($object, 'as:context', '@id');
1305                 $object_data['conversation'] = JsonLD::fetchElement($object, 'ostatus:conversation', '@id');
1306                 $object_data['sensitive'] = JsonLD::fetchElement($object, 'as:sensitive');
1307                 $object_data['name'] = JsonLD::fetchElement($object, 'as:name', '@value');
1308                 $object_data['summary'] = JsonLD::fetchElement($object, 'as:summary', '@value');
1309                 $object_data['content'] = JsonLD::fetchElement($object, 'as:content', '@value');
1310                 $object_data = self::getSource($object, $object_data);
1311                 $object_data['start-time'] = JsonLD::fetchElement($object, 'as:startTime', '@value');
1312                 $object_data['end-time'] = JsonLD::fetchElement($object, 'as:endTime', '@value');
1313                 $object_data['location'] = $location;
1314                 $object_data['latitude'] = JsonLD::fetchElement($object, 'as:location', 'as:latitude', '@type', 'as:Place');
1315                 $object_data['latitude'] = JsonLD::fetchElement($object_data, 'latitude', '@value');
1316                 $object_data['longitude'] = JsonLD::fetchElement($object, 'as:location', 'as:longitude', '@type', 'as:Place');
1317                 $object_data['longitude'] = JsonLD::fetchElement($object_data, 'longitude', '@value');
1318                 $object_data['attachments'] = self::processAttachments(JsonLD::fetchElementArray($object, 'as:attachment') ?? []);
1319                 $object_data['tags'] = self::processTags(JsonLD::fetchElementArray($object, 'as:tag') ?? []);
1320                 $object_data['emojis'] = self::processEmojis(JsonLD::fetchElementArray($object, 'as:tag', 'toot:Emoji') ?? []);
1321                 $object_data['generator'] = JsonLD::fetchElement($object, 'as:generator', 'as:name', '@type', 'as:Application');
1322                 $object_data['generator'] = JsonLD::fetchElement($object_data, 'generator', '@value');
1323                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'as:url', '@id');
1324
1325                 // Special treatment for Hubzilla links
1326                 if (is_array($object_data['alternate-url'])) {
1327                         $object_data['alternate-url'] = JsonLD::fetchElement($object_data['alternate-url'], 'as:href', '@id');
1328
1329                         if (!is_string($object_data['alternate-url'])) {
1330                                 $object_data['alternate-url'] = JsonLD::fetchElement($object['as:url'], 'as:href', '@id');
1331                         }
1332                 }
1333
1334                 if (in_array($object_data['object_type'], ['as:Audio', 'as:Video'])) {
1335                         $object_data = self::processAttachmentUrls($object, $object_data);
1336                 }
1337
1338                 $receiverdata = self::getReceivers($object, $object_data['actor'], $object_data['tags'], true);
1339                 $receivers = $reception_types = [];
1340                 foreach ($receiverdata as $key => $data) {
1341                         $receivers[$key] = $data['uid'];
1342                         $reception_types[$data['uid']] = $data['type'] ?? 0;
1343                 }
1344
1345                 $object_data['receiver'] = $receivers;
1346                 $object_data['reception_type'] = $reception_types;
1347
1348                 $object_data['unlisted'] = in_array(-1, $object_data['receiver']);
1349                 unset($object_data['receiver']['uid:-1']);
1350
1351                 // Common object data:
1352
1353                 // Unhandled
1354                 // @context, type, actor, signature, mediaType, duration, replies, icon
1355
1356                 // Also missing: (Defined in the standard, but currently unused)
1357                 // audience, preview, endTime, startTime, image
1358
1359                 // Data in Notes:
1360
1361                 // Unhandled
1362                 // contentMap, announcement_count, announcements, context_id, likes, like_count
1363                 // inReplyToStatusId, shares, quoteUrl, statusnetConversationId
1364
1365                 // Data in video:
1366
1367                 // To-Do?
1368                 // category, licence, language, commentsEnabled
1369
1370                 // Unhandled
1371                 // views, waitTranscoding, state, support, subtitleLanguage
1372                 // likes, dislikes, shares, comments
1373
1374                 return $object_data;
1375         }
1376 }