src/Protocol/ActivityPub/Receiver.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2010-2021, the Friendica project
   4  *
   5  * @license GNU AGPL version 3 or any later version
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU Affero General Public License as
   9  * published by the Free Software Foundation, either version 3 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU Affero General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Affero General Public License
  18  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  19  *
  20  */
  21
  22 namespace Friendica\Protocol\ActivityPub;
  23
  24 use Friendica\Content\Text\BBCode;
  25 use Friendica\Database\DBA;
  26 use Friendica\Content\Text\HTML;
  27 use Friendica\Content\Text\Markdown;
  28 use Friendica\Core\Logger;
  29 use Friendica\Core\Protocol;
  30 use Friendica\Model\Contact;
  31 use Friendica\Model\APContact;
  32 use Friendica\Model\Item;
  33 use Friendica\Model\Post;
  34 use Friendica\Model\User;
  35 use Friendica\Protocol\Activity;
  36 use Friendica\Protocol\ActivityPub;
  37 use Friendica\Util\HTTPSignature;
  38 use Friendica\Util\JsonLD;
  39 use Friendica\Util\LDSignature;
  40 use Friendica\Util\Strings;
  41
  42 /**
  43  * ActivityPub Receiver Protocol class
  44  *
  45  * To-Do:
  46  * @todo Undo Announce
  47  *
  48  * Check what this is meant to do:
  49  * - Add
  50  * - Block
  51  * - Flag
  52  * - Remove
  53  * - Undo Block
  54  */
  55 class Receiver
  56 {
  57         const PUBLIC_COLLECTION = 'as:Public';
  58         const ACCOUNT_TYPES = ['as:Person', 'as:Organization', 'as:Service', 'as:Group', 'as:Application'];
  59         const CONTENT_TYPES = ['as:Note', 'as:Article', 'as:Video', 'as:Image', 'as:Event', 'as:Audio'];
  60         const ACTIVITY_TYPES = ['as:Like', 'as:Dislike', 'as:Accept', 'as:Reject', 'as:TentativeAccept'];
  61
  62         const TARGET_UNKNOWN = 0;
  63         const TARGET_TO = 1;
  64         const TARGET_CC = 2;
  65         const TARGET_BTO = 3;
  66         const TARGET_BCC = 4;
  67         const TARGET_FOLLOWER = 5;
  68         const TARGET_ANSWER = 6;
  69         const TARGET_GLOBAL = 7;
  70
  71         /**
  72          * Checks incoming message from the inbox
  73          *
  74          * @param         $body
  75          * @param         $header
  76          * @param integer $uid User ID
  77          * @throws \Exception
  78          */
  79         public static function processInbox($body, $header, $uid)
  80         {
  81                 $activity = json_decode($body, true);
  82                 if (empty($activity)) {
  83                         Logger::warning('Invalid body.');
  84                         return;
  85                 }
  86
  87                 $ldactivity = JsonLD::compact($activity);
  88
  89                 $actor = JsonLD::fetchElement($ldactivity, 'as:actor', '@id');
  90
  91                 $apcontact = APContact::getByURL($actor);
  92                 if (empty($apcontact)) {
  93                         Logger::notice('Unable to retrieve AP contact for actor - message is discarded', ['actor' => $actor]);
  94                         return;
  95                 } elseif ($apcontact['type'] == 'Application' && $apcontact['nick'] == 'relay') {
  96                         self::processRelayPost($ldactivity, $actor);
  97                         return;
  98                 } else {
  99                         APContact::unmarkForArchival($apcontact);
 100                 }
 101
 102                 $http_signer = HTTPSignature::getSigner($body, $header);
 103                 if ($http_signer === false) {
 104                         Logger::warning('Invalid HTTP signature, message will be discarded.');
 105                         return;
 106                 } elseif (empty($http_signer)) {
 107                         Logger::info('Signer is a tombstone. The message will be discarded, the signer account is deleted.');
 108                         return;
 109                 } else {
 110                         Logger::info('Valid HTTP signature', ['signer' => $http_signer]);
 111                 }
 112
 113                 $signer = [$http_signer];
 114
 115                 Logger::info('Message for user ' . $uid . ' is from actor ' . $actor);
 116
 117                 if (LDSignature::isSigned($activity)) {
 118                         $ld_signer = LDSignature::getSigner($activity);
 119                         if (empty($ld_signer)) {
 120                                 Logger::info('Invalid JSON-LD signature from ' . $actor);
 121                         } elseif ($ld_signer != $http_signer) {
 122                                 $signer[] = $ld_signer;
 123                         }
 124                         if (!empty($ld_signer && ($actor == $http_signer))) {
 125                                 Logger::info('The HTTP and the JSON-LD signature belong to ' . $ld_signer);
 126                                 $trust_source = true;
 127                         } elseif (!empty($ld_signer)) {
 128                                 Logger::info('JSON-LD signature is signed by ' . $ld_signer);
 129                                 $trust_source = true;
 130                         } elseif ($actor == $http_signer) {
 131                                 Logger::info('Bad JSON-LD signature, but HTTP signer fits the actor.');
 132                                 $trust_source = true;
 133                         } else {
 134                                 Logger::info('Invalid JSON-LD signature and the HTTP signer is different.');
 135                                 $trust_source = false;
 136                         }
 137                 } elseif ($actor == $http_signer) {
 138                         Logger::info('Trusting post without JSON-LD signature, The actor fits the HTTP signer.');
 139                         $trust_source = true;
 140                 } else {
 141                         Logger::info('No JSON-LD signature, different actor.');
 142                         $trust_source = false;
 143                 }
 144
 145                 self::processActivity($ldactivity, $body, $uid, $trust_source, true, $signer);
 146         }
 147
 148         /**
 149          * Process incoming posts from relays
 150          *
 151          * @param array  $activity
 152          * @param string $actor
 153          * @return void
 154          */
 155         private static function processRelayPost(array $activity, string $actor)
 156         {
 157                 $type = JsonLD::fetchElement($activity, '@type');
 158                 if (!$type) {
 159                         Logger::info('Empty type', ['activity' => $activity]);
 160                         return;
 161                 }
 162
 163                 if ($type != 'as:Announce') {
 164                         Logger::info('Not an announcement', ['activity' => $activity]);
 165                         return;
 166                 }
 167
 168                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 169                 if (empty($object_id)) {
 170                         Logger::info('No object id found', ['activity' => $activity]);
 171                         return;
 172                 }
 173
 174                 $contact = Contact::getByURL($actor);
 175                 if (empty($contact)) {
 176                         Logger::info('Relay contact not found', ['actor' => $actor]);
 177                         return;
 178                 }
 179
 180                 if (!in_array($contact['rel'], [Contact::SHARING, Contact::FRIEND])) {
 181                         Logger::notice('Relay is no sharer', ['actor' => $actor]);
 182                         return;
 183                 }
 184
 185                 Logger::info('Got relayed message id', ['id' => $object_id]);
 186
 187                 $item_id = Item::searchByLink($object_id);
 188                 if ($item_id) {
 189                         Logger::info('Relayed message already exists', ['id' => $object_id, 'item' => $item_id]);
 190                         return;
 191                 }
 192
 193                 $id = Processor::fetchMissingActivity($object_id, [], $actor);
 194                 if (empty($id)) {
 195                         Logger::notice('Relayed message had not been fetched', ['id' => $object_id]);
 196                         return;
 197                 }
 198
 199                 $item_id = Item::searchByLink($object_id);
 200                 if ($item_id) {
 201                         Logger::info('Relayed message had been fetched and stored', ['id' => $object_id, 'item' => $item_id]);
 202                 } else {
 203                         Logger::notice('Relayed message had not been stored', ['id' => $object_id]);
 204                 }
 205         }
 206
 207         /**
 208          * Fetches the object type for a given object id
 209          *
 210          * @param array   $activity
 211          * @param string  $object_id Object ID of the the provided object
 212          * @param integer $uid       User ID
 213          *
 214          * @return string with object type
 215          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 216          * @throws \ImagickException
 217          */
 218         private static function fetchObjectType($activity, $object_id, $uid = 0)
 219         {
 220                 if (!empty($activity['as:object'])) {
 221                         $object_type = JsonLD::fetchElement($activity['as:object'], '@type');
 222                         if (!empty($object_type)) {
 223                                 return $object_type;
 224                         }
 225                 }
 226
 227                 if (Post::exists(['uri' => $object_id, 'gravity' => [GRAVITY_PARENT, GRAVITY_COMMENT]])) {
 228                         // We just assume "note" since it doesn't make a difference for the further processing
 229                         return 'as:Note';
 230                 }
 231
 232                 $profile = APContact::getByURL($object_id);
 233                 if (!empty($profile['type'])) {
 234                         APContact::unmarkForArchival($profile);
 235                         return 'as:' . $profile['type'];
 236                 }
 237
 238                 $data = ActivityPub::fetchContent($object_id, $uid);
 239                 if (!empty($data)) {
 240                         $object = JsonLD::compact($data);
 241                         $type = JsonLD::fetchElement($object, '@type');
 242                         if (!empty($type)) {
 243                                 return $type;
 244                         }
 245                 }
 246
 247                 return null;
 248         }
 249
 250         /**
 251          * Prepare the object array
 252          *
 253          * @param array   $activity     Array with activity data
 254          * @param integer $uid          User ID
 255          * @param boolean $push         Message had been pushed to our system
 256          * @param boolean $trust_source Do we trust the source?
 257          *
 258          * @return array with object data
 259          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 260          * @throws \ImagickException
 261          */
 262         public static function prepareObjectData($activity, $uid, $push, &$trust_source)
 263         {
 264                 $id = JsonLD::fetchElement($activity, '@id');
 265                 if (!empty($id) && !$trust_source) {
 266                         $fetched_activity = ActivityPub::fetchContent($id, $uid ?? 0);
 267                         if (!empty($fetched_activity)) {
 268                                 $object = JsonLD::compact($fetched_activity);
 269                                 $fetched_id = JsonLD::fetchElement($object, '@id');
 270                                 if ($fetched_id == $id) {
 271                                         Logger::info('Activity had been fetched successfully', ['id' => $id]);
 272                                         $trust_source = true;
 273                                         $activity = $object;
 274                                 } else {
 275                                         Logger::info('Activity id is not equal', ['id' => $id, 'fetched' => $fetched_id]);
 276                                 }
 277                         } else {
 278                                 Logger::info('Activity could not been fetched', ['id' => $id]);
 279                         }
 280                 }
 281
 282                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 283                 if (empty($actor)) {
 284                         Logger::info('Empty actor', ['activity' => $activity]);
 285                         return [];
 286                 }
 287
 288                 $type = JsonLD::fetchElement($activity, '@type');
 289
 290                 // Fetch all receivers from to, cc, bto and bcc
 291                 $receiverdata = self::getReceivers($activity, $actor);
 292                 $receivers = $reception_types = [];
 293                 foreach ($receiverdata as $key => $data) {
 294                         $receivers[$key] = $data['uid'];
 295                         $reception_types[$data['uid']] = $data['type'] ?? self::TARGET_UNKNOWN;
 296                 }
 297
 298                 // When it is a delivery to a personal inbox we add that user to the receivers
 299                 if (!empty($uid)) {
 300                         $additional = [$uid => $uid];
 301                         $receivers = array_replace($receivers, $additional);
 302                         if (empty($activity['thread-completion']) && (empty($reception_types[$uid]) || in_array($reception_types[$uid], [self::TARGET_UNKNOWN, self::TARGET_FOLLOWER, self::TARGET_ANSWER, self::TARGET_GLOBAL]))) {
 303                                 $reception_types[$uid] = self::TARGET_BCC;
 304                         }
 305                 } else {
 306                         // We possibly need some user to fetch private content,
 307                         // so we fetch the first out ot the list.
 308                         $uid = self::getFirstUserFromReceivers($receivers);
 309                 }
 310
 311                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 312                 if (empty($object_id)) {
 313                         Logger::info('No object found');
 314                         return [];
 315                 }
 316
 317                 if (!is_string($object_id)) {
 318                         Logger::info('Invalid object id', ['object' => $object_id]);
 319                         return [];
 320                 }
 321
 322                 $object_type = self::fetchObjectType($activity, $object_id, $uid);
 323
 324                 // Fetch the content only on activities where this matters
 325                 // We can receive "#emojiReaction" when fetching content from Hubzilla systems
 326                 if (in_array($type, ['as:Create', 'as:Update', 'as:Announce']) || strpos($type, '#emojiReaction')) {
 327                         // Always fetch on "Announce"
 328                         $object_data = self::fetchObject($object_id, $activity['as:object'], $trust_source && ($type != 'as:Announce'), $uid);
 329                         if (empty($object_data)) {
 330                                 Logger::info("Object data couldn't be processed");
 331                                 return [];
 332                         }
 333
 334                         $object_data['object_id'] = $object_id;
 335
 336                         if ($type == 'as:Announce') {
 337                                 $object_data['push'] = false;
 338                         } else {
 339                                 $object_data['push'] = $push;
 340                         }
 341
 342                         // Test if it is an answer to a mail
 343                         if (DBA::exists('mail', ['uri' => $object_data['reply-to-id']])) {
 344                                 $object_data['directmessage'] = true;
 345                         } else {
 346                                 $object_data['directmessage'] = JsonLD::fetchElement($activity, 'litepub:directMessage');
 347                         }
 348                 } elseif (in_array($type, array_merge(self::ACTIVITY_TYPES, ['as:Follow'])) && in_array($object_type, self::CONTENT_TYPES)) {
 349                         // Create a mostly empty array out of the activity data (instead of the object).
 350                         // This way we later don't have to check for the existence of ech individual array element.
 351                         $object_data = self::processObject($activity);
 352                         $object_data['name'] = $type;
 353                         $object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 354                         $object_data['object_id'] = $object_id;
 355                         $object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
 356                         $object_data['push'] = $push;
 357                 } elseif (in_array($type, ['as:Add'])) {
 358                         $object_data = [];
 359                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 360                         $object_data['target_id'] = JsonLD::fetchElement($activity, 'as:target', '@id');
 361                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 362                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 363                         $object_data['object_content'] = JsonLD::fetchElement($activity['as:object'], 'as:content', '@type');
 364                         $object_data['push'] = $push;
 365                 } else {
 366                         $object_data = [];
 367                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 368                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 369                         $object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor', '@id');
 370                         $object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
 371                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 372                         $object_data['push'] = $push;
 373
 374                         // An Undo is done on the object of an object, so we need that type as well
 375                         if (($type == 'as:Undo') && !empty($object_data['object_object'])) {
 376                                 $object_data['object_object_type'] = self::fetchObjectType([], $object_data['object_object'], $uid);
 377                         }
 378                 }
 379
 380                 $object_data = self::addActivityFields($object_data, $activity);
 381
 382                 if (empty($object_data['object_type'])) {
 383                         $object_data['object_type'] = $object_type;
 384                 }
 385
 386                 $object_data['type'] = $type;
 387                 $object_data['actor'] = $actor;
 388                 $object_data['item_receiver'] = $receivers;
 389                 $object_data['receiver'] = array_replace($object_data['receiver'] ?? [], $receivers);
 390                 $object_data['reception_type'] = array_replace($object_data['reception_type'] ?? [], $reception_types);
 391
 392                 $author = $object_data['author'] ?? $actor;
 393                 if (!empty($author) && !empty($object_data['id'])) {
 394                         $author_host = parse_url($author, PHP_URL_HOST);
 395                         $id_host = parse_url($object_data['id'], PHP_URL_HOST);
 396                         if ($author_host == $id_host) {
 397                                 Logger::info('Valid hosts', ['type' => $type, 'host' => $id_host]);
 398                         } else {
 399                                 Logger::notice('Differing hosts on author and id', ['type' => $type, 'author' => $author_host, 'id' => $id_host]);
 400                                 $trust_source = false;
 401                         }
 402                 }
 403
 404                 Logger::info('Processing ' . $object_data['type'] . ' ' . $object_data['object_type'] . ' ' . $object_data['id']);
 405
 406                 return $object_data;
 407         }
 408
 409         /**
 410          * Fetches the first user id from the receiver array
 411          *
 412          * @param array $receivers Array with receivers
 413          * @return integer user id;
 414          */
 415         public static function getFirstUserFromReceivers($receivers)
 416         {
 417                 foreach ($receivers as $receiver) {
 418                         if (!empty($receiver)) {
 419                                 return $receiver;
 420                         }
 421                 }
 422                 return 0;
 423         }
 424
 425         /**
 426          * Processes the activity object
 427          *
 428          * @param array   $activity     Array with activity data
 429          * @param string  $body
 430          * @param integer $uid          User ID
 431          * @param boolean $trust_source Do we trust the source?
 432          * @param boolean $push         Message had been pushed to our system
 433          * @throws \Exception
 434          */
 435         public static function processActivity($activity, string $body = '', int $uid = null, bool $trust_source = false, bool $push = false, array $signer = [])
 436         {
 437                 $type = JsonLD::fetchElement($activity, '@type');
 438                 if (!$type) {
 439                         Logger::info('Empty type', ['activity' => $activity]);
 440                         return;
 441                 }
 442
 443                 if (!JsonLD::fetchElement($activity, 'as:object', '@id')) {
 444                         Logger::info('Empty object', ['activity' => $activity]);
 445                         return;
 446                 }
 447
 448                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 449                 if (empty($actor)) {
 450                         Logger::info('Empty actor', ['activity' => $activity]);
 451                         return;
 452                 }
 453
 454                 if (is_array($activity['as:object'])) {
 455                         $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
 456                 } else {
 457                         $attributed_to = '';
 458                 }
 459
 460                 // Test the provided signatures against the actor and "attributedTo"
 461                 if ($trust_source) {
 462                         if (!empty($attributed_to) && !empty($actor)) {
 463                                 $trust_source = (in_array($actor, $signer) && in_array($attributed_to, $signer));
 464                         } else {
 465                                 $trust_source = in_array($actor, $signer);
 466                         }
 467                 }
 468
 469                 // $trust_source is called by reference and is set to true if the content was retrieved successfully
 470                 $object_data = self::prepareObjectData($activity, $uid, $push, $trust_source);
 471                 if (empty($object_data)) {
 472                         Logger::info('No object data found', ['activity' => $activity]);
 473                         return;
 474                 }
 475
 476                 if (!$trust_source) {
 477                         Logger::info('Activity trust could not be achieved.',  ['id' => $object_data['object_id'], 'type' => $type, 'signer' => $signer, 'actor' => $actor, 'attributedTo' => $attributed_to]);
 478                         return;
 479                 }
 480
 481                 if (!empty($body) && empty($object_data['raw'])) {
 482                         $object_data['raw'] = $body;
 483                 }
 484
 485                 // Internal flag for thread completion. See Processor.php
 486                 if (!empty($activity['thread-completion'])) {
 487                         $object_data['thread-completion'] = $activity['thread-completion'];
 488                 }
 489
 490                 // Internal flag for posts that arrived via relay
 491                 if (!empty($activity['from-relay'])) {
 492                         $object_data['from-relay'] = $activity['from-relay'];
 493                 }
 494
 495                 switch ($type) {
 496                         case 'as:Create':
 497                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 498                                         $item = ActivityPub\Processor::createItem($object_data);
 499                                         ActivityPub\Processor::postItem($object_data, $item);
 500                                 }
 501                                 break;
 502
 503                         case 'as:Add':
 504                                 if ($object_data['object_type'] == 'as:tag') {
 505                                         ActivityPub\Processor::addTag($object_data);
 506                                 }
 507                                 break;
 508
 509                         case 'as:Announce':
 510                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 511                                         $object_data['thread-completion'] = Contact::getIdForURL($actor);
 512
 513                                         $item = ActivityPub\Processor::createItem($object_data);
 514                                         if (empty($item)) {
 515                                                 return;
 516                                         }
 517
 518                                         $item['post-reason'] = Item::PR_ANNOUNCEMENT;
 519                                         ActivityPub\Processor::postItem($object_data, $item);
 520
 521                                         $announce_object_data = self::processObject($activity);
 522                                         $announce_object_data['name'] = $type;
 523                                         $announce_object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 524                                         $announce_object_data['object_id'] = $object_data['object_id'];
 525                                         $announce_object_data['object_type'] = $object_data['object_type'];
 526                                         $announce_object_data['push'] = $push;
 527
 528                                         if (!empty($body)) {
 529                                                 $announce_object_data['raw'] = $body;
 530                                         }
 531
 532                                         ActivityPub\Processor::createActivity($announce_object_data, Activity::ANNOUNCE);
 533                                 }
 534                                 break;
 535
 536                         case 'as:Like':
 537                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 538                                         ActivityPub\Processor::createActivity($object_data, Activity::LIKE);
 539                                 }
 540                                 break;
 541
 542                         case 'as:Dislike':
 543                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 544                                         ActivityPub\Processor::createActivity($object_data, Activity::DISLIKE);
 545                                 }
 546                                 break;
 547
 548                         case 'as:TentativeAccept':
 549                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 550                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDMAYBE);
 551                                 }
 552                                 break;
 553
 554                         case 'as:Update':
 555                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 556                                         ActivityPub\Processor::updateItem($object_data);
 557                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 558                                         ActivityPub\Processor::updatePerson($object_data);
 559                                 }
 560                                 break;
 561
 562                         case 'as:Delete':
 563                                 if ($object_data['object_type'] == 'as:Tombstone') {
 564                                         ActivityPub\Processor::deleteItem($object_data);
 565                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 566                                         ActivityPub\Processor::deletePerson($object_data);
 567                                 }
 568                                 break;
 569
 570                         case 'as:Follow':
 571                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 572                                         ActivityPub\Processor::followUser($object_data);
 573                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 574                                         $object_data['reply-to-id'] = $object_data['object_id'];
 575                                         ActivityPub\Processor::createActivity($object_data, Activity::FOLLOW);
 576                                 }
 577                                 break;
 578
 579                         case 'as:Accept':
 580                                 if ($object_data['object_type'] == 'as:Follow') {
 581                                         ActivityPub\Processor::acceptFollowUser($object_data);
 582                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 583                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTEND);
 584                                 }
 585                                 break;
 586
 587                         case 'as:Reject':
 588                                 if ($object_data['object_type'] == 'as:Follow') {
 589                                         ActivityPub\Processor::rejectFollowUser($object_data);
 590                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 591                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDNO);
 592                                 }
 593                                 break;
 594
 595                         case 'as:Undo':
 596                                 if (($object_data['object_type'] == 'as:Follow') &&
 597                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 598                                         ActivityPub\Processor::undoFollowUser($object_data);
 599                                 } elseif (($object_data['object_type'] == 'as:Accept') &&
 600                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 601                                         ActivityPub\Processor::rejectFollowUser($object_data);
 602                                 } elseif (in_array($object_data['object_type'], self::ACTIVITY_TYPES) &&
 603                                         in_array($object_data['object_object_type'], self::CONTENT_TYPES)) {
 604                                         ActivityPub\Processor::undoActivity($object_data);
 605                                 }
 606                                 break;
 607
 608                         default:
 609                                 Logger::info('Unknown activity: ' . $type . ' ' . $object_data['object_type']);
 610                                 break;
 611                 }
 612         }
 613
 614         /**
 615          * Fetch the receiver list from an activity array
 616          *
 617          * @param array   $activity
 618          * @param string  $actor
 619          * @param array   $tags
 620          * @param boolean $fetch_unlisted
 621          *
 622          * @return array with receivers (user id)
 623          * @throws \Exception
 624          */
 625         private static function getReceivers($activity, $actor, $tags = [], $fetch_unlisted = false)
 626         {
 627                 $reply = $receivers = [];
 628
 629                 // When it is an answer, we inherite the receivers from the parent
 630                 $replyto = JsonLD::fetchElement($activity, 'as:inReplyTo', '@id');
 631                 if (!empty($replyto)) {
 632                         $reply = [$replyto];
 633
 634                         // Fix possibly wrong item URI (could be an answer to a plink uri)
 635                         $fixedReplyTo = Item::getURIByLink($replyto);
 636                         if (!empty($fixedReplyTo)) {
 637                                 $reply[] = $fixedReplyTo;
 638                         }
 639                 }
 640
 641                 // Fetch all posts that refer to the object id
 642                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 643                 if (!empty($object_id)) {
 644                         $reply[] = $object_id;
 645                 }
 646
 647                 if (!empty($reply)) {
 648                         $parents = Post::select(['uid'], ['uri' => $reply]);
 649                         while ($parent = Post::fetch($parents)) {
 650                                 $receivers[$parent['uid']] = ['uid' => $parent['uid'], 'type' => self::TARGET_ANSWER];
 651                         }
 652                         DBA::close($parents);
 653                 }
 654
 655                 if (!empty($actor)) {
 656                         $profile   = APContact::getByURL($actor);
 657                         $followers = $profile['followers'] ?? '';
 658                         $is_forum  = ($actor['type'] ?? '') == 'Group';
 659                         Logger::info('Got actor and followers', ['actor' => $actor, 'followers' => $followers]);
 660                 } else {
 661                         Logger::info('Empty actor', ['activity' => $activity]);
 662                         $followers = '';
 663                         $is_forum  = false;
 664                 }
 665
 666                 // We have to prevent false follower assumptions upon thread completions
 667                 $follower_target = empty($activity['thread-completion']) ? self::TARGET_FOLLOWER : self::TARGET_UNKNOWN;
 668
 669                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
 670                         $receiver_list = JsonLD::fetchElementArray($activity, $element, '@id');
 671                         if (empty($receiver_list)) {
 672                                 continue;
 673                         }
 674
 675                         foreach ($receiver_list as $receiver) {
 676                                 if ($receiver == self::PUBLIC_COLLECTION) {
 677                                         $receivers[0] = ['uid' => 0, 'type' => self::TARGET_GLOBAL];
 678                                 }
 679
 680                                 // Add receiver "-1" for unlisted posts
 681                                 if ($fetch_unlisted && ($receiver == self::PUBLIC_COLLECTION) && ($element == 'as:cc')) {
 682                                         $receivers[-1] = ['uid' => -1, 'type' => self::TARGET_GLOBAL];
 683                                 }
 684
 685                                 // Fetch the receivers for the public and the followers collection
 686                                 if ((($receiver == $followers) || (($receiver == self::PUBLIC_COLLECTION) && !$is_forum)) && !empty($actor)) {
 687                                         $receivers = self::getReceiverForActor($actor, $tags, $receivers, $follower_target);
 688                                         continue;
 689                                 }
 690
 691                                 // Fetching all directly addressed receivers
 692                                 $condition = ['self' => true, 'nurl' => Strings::normaliseLink($receiver)];
 693                                 $contact = DBA::selectFirst('contact', ['uid', 'contact-type'], $condition);
 694                                 if (!DBA::isResult($contact)) {
 695                                         continue;
 696                                 }
 697
 698                                 // Check if the potential receiver is following the actor
 699                                 // Exception: The receiver is targetted via "to" or this is a comment
 700                                 if ((($element != 'as:to') && empty($replyto)) || ($contact['contact-type'] == Contact::TYPE_COMMUNITY)) {
 701                                         $networks = Protocol::FEDERATED;
 702                                         $condition = ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
 703                                                 'network' => $networks, 'archive' => false, 'pending' => false, 'uid' => $contact['uid']];
 704
 705                                         // Forum posts are only accepted from forum contacts
 706                                         if ($contact['contact-type'] == Contact::TYPE_COMMUNITY) {
 707                                                 $condition['rel'] = [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER];
 708                                         }
 709
 710                                         if (!DBA::exists('contact', $condition)) {
 711                                                 continue;
 712                                         }
 713                                 }
 714
 715                                 $type = $receivers[$contact['uid']]['type'] ?? self::TARGET_UNKNOWN;
 716                                 if (in_array($type, [self::TARGET_UNKNOWN, self::TARGET_FOLLOWER, self::TARGET_ANSWER, self::TARGET_GLOBAL])) {
 717                                         switch ($element) {
 718                                                 case 'as:to':
 719                                                         $type = self::TARGET_TO;
 720                                                         break;
 721                                                 case 'as:cc':
 722                                                         $type = self::TARGET_CC;
 723                                                         break;
 724                                                 case 'as:bto':
 725                                                         $type = self::TARGET_BTO;
 726                                                         break;
 727                                                 case 'as:bcc':
 728                                                         $type = self::TARGET_BCC;
 729                                                         break;
 730                                         }
 731
 732                                         $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $type];
 733                                 }
 734                         }
 735                 }
 736
 737                 self::switchContacts($receivers, $actor);
 738
 739                 return $receivers;
 740         }
 741
 742         /**
 743          * Fetch the receiver list of a given actor
 744          *
 745          * @param string  $actor
 746          * @param array   $tags
 747          * @param array   $receivers
 748          * @param integer $target_type
 749          *
 750          * @return array with receivers (user id)
 751          * @throws \Exception
 752          */
 753         private static function getReceiverForActor($actor, $tags, $receivers, $target_type)
 754         {
 755                 $basecondition = ['rel' => [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER],
 756                         'network' => Protocol::FEDERATED, 'archive' => false, 'pending' => false];
 757
 758                 $condition = DBA::mergeConditions($basecondition, ["`nurl` = ? AND `uid` != ?", Strings::normaliseLink($actor), 0]);
 759                 $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
 760                 while ($contact = DBA::fetch($contacts)) {
 761                         if (empty($receivers[$contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
 762                                 $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $target_type];
 763                         }
 764                 }
 765                 DBA::close($contacts);
 766
 767                 // The queries are split because of performance issues
 768                 $condition = DBA::mergeConditions($basecondition, ["`alias` IN (?, ?) AND `uid` != ?", Strings::normaliseLink($actor), $actor, 0]);
 769                 $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
 770                 while ($contact = DBA::fetch($contacts)) {
 771                         if (empty($receivers[$contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
 772                                 $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $target_type];
 773                         }
 774                 }
 775                 DBA::close($contacts);
 776                 return $receivers;
 777         }
 778
 779         /**
 780          * Tests if the contact is a valid receiver for this actor
 781          *
 782          * @param array  $contact
 783          * @param string $actor
 784          * @param array  $tags
 785          *
 786          * @return bool with receivers (user id)
 787          * @throws \Exception
 788          */
 789         private static function isValidReceiverForActor($contact, $tags)
 790         {
 791                 // Are we following the contact? Then this is a valid receiver
 792                 if (in_array($contact['rel'], [Contact::SHARING, Contact::FRIEND])) {
 793                         return true;
 794                 }
 795
 796                 // When the possible receiver isn't a community, then it is no valid receiver
 797                 $owner = User::getOwnerDataById($contact['uid']);
 798                 if (empty($owner) || ($owner['contact-type'] != Contact::TYPE_COMMUNITY)) {
 799                         return false;
 800                 }
 801
 802                 // Is the community account tagged?
 803                 foreach ($tags as $tag) {
 804                         if ($tag['type'] != 'Mention') {
 805                                 continue;
 806                         }
 807
 808                         if (Strings::compareLink($tag['href'], $owner['url'])) {
 809                                 return true;
 810                         }
 811                 }
 812
 813                 return false;
 814         }
 815
 816         /**
 817          * Switches existing contacts to ActivityPub
 818          *
 819          * @param integer $cid Contact ID
 820          * @param integer $uid User ID
 821          * @param string  $url Profile URL
 822          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 823          * @throws \ImagickException
 824          */
 825         public static function switchContact($cid, $uid, $url)
 826         {
 827                 if (DBA::exists('contact', ['id' => $cid, 'network' => Protocol::ACTIVITYPUB])) {
 828                         Logger::info('Contact is already ActivityPub', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
 829                         return;
 830                 }
 831
 832                 if (Contact::updateFromProbe($cid)) {
 833                         Logger::info('Update was successful', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
 834                 }
 835
 836                 // Send a new follow request to be sure that the connection still exists
 837                 if (($uid != 0) && DBA::exists('contact', ['id' => $cid, 'rel' => [Contact::SHARING, Contact::FRIEND], 'network' => Protocol::ACTIVITYPUB])) {
 838                         Logger::info('Contact had been switched to ActivityPub. Sending a new follow request.', ['uid' => $uid, 'url' => $url]);
 839                         ActivityPub\Transmitter::sendActivity('Follow', $url, $uid);
 840                 }
 841         }
 842
 843         /**
 844          *
 845          *
 846          * @param $receivers
 847          * @param $actor
 848          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 849          * @throws \ImagickException
 850          */
 851         private static function switchContacts($receivers, $actor)
 852         {
 853                 if (empty($actor)) {
 854                         return;
 855                 }
 856
 857                 foreach ($receivers as $receiver) {
 858                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver['uid'], 'network' => Protocol::OSTATUS, 'nurl' => Strings::normaliseLink($actor)]);
 859                         if (DBA::isResult($contact)) {
 860                                 self::switchContact($contact['id'], $receiver['uid'], $actor);
 861                         }
 862
 863                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver['uid'], 'network' => Protocol::OSTATUS, 'alias' => [Strings::normaliseLink($actor), $actor]]);
 864                         if (DBA::isResult($contact)) {
 865                                 self::switchContact($contact['id'], $receiver['uid'], $actor);
 866                         }
 867                 }
 868         }
 869
 870         /**
 871          *
 872          *
 873          * @param       $object_data
 874          * @param array $activity
 875          *
 876          * @return mixed
 877          */
 878         private static function addActivityFields($object_data, $activity)
 879         {
 880                 if (!empty($activity['published']) && empty($object_data['published'])) {
 881                         $object_data['published'] = JsonLD::fetchElement($activity, 'as:published', '@value');
 882                 }
 883
 884                 if (!empty($activity['diaspora:guid']) && empty($object_data['diaspora:guid'])) {
 885                         $object_data['diaspora:guid'] = JsonLD::fetchElement($activity, 'diaspora:guid', '@value');
 886                 }
 887
 888                 $object_data['service'] = JsonLD::fetchElement($activity, 'as:instrument', 'as:name', '@type', 'as:Service');
 889                 $object_data['service'] = JsonLD::fetchElement($object_data, 'service', '@value');
 890
 891                 if (!empty($object_data['object_id'])) {
 892                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
 893                         $objectId = Item::getURIByLink($object_data['object_id']);
 894                         if (!empty($objectId) && ($object_data['object_id'] != $objectId)) {
 895                                 Logger::notice('Fix wrong object-id', ['received' => $object_data['object_id'], 'correct' => $objectId]);
 896                                 $object_data['object_id'] = $objectId;
 897                         }
 898                 }
 899
 900                 return $object_data;
 901         }
 902
 903         /**
 904          * Fetches the object data from external ressources if needed
 905          *
 906          * @param string  $object_id    Object ID of the the provided object
 907          * @param array   $object       The provided object array
 908          * @param boolean $trust_source Do we trust the provided object?
 909          * @param integer $uid          User ID for the signature that we use to fetch data
 910          *
 911          * @return array|false with trusted and valid object data
 912          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 913          * @throws \ImagickException
 914          */
 915         private static function fetchObject(string $object_id, array $object = [], bool $trust_source = false, int $uid = 0)
 916         {
 917                 // By fetching the type we check if the object is complete.
 918                 $type = JsonLD::fetchElement($object, '@type');
 919
 920                 if (!$trust_source || empty($type)) {
 921                         $data = ActivityPub::fetchContent($object_id, $uid);
 922                         if (!empty($data)) {
 923                                 $object = JsonLD::compact($data);
 924                                 Logger::info('Fetched content for ' . $object_id);
 925                         } else {
 926                                 Logger::info('Empty content for ' . $object_id . ', check if content is available locally.');
 927
 928                                 $item = Post::selectFirst(Item::DELIVER_FIELDLIST, ['uri' => $object_id]);
 929                                 if (!DBA::isResult($item)) {
 930                                         Logger::info('Object with url ' . $object_id . ' was not found locally.');
 931                                         return false;
 932                                 }
 933                                 Logger::info('Using already stored item for url ' . $object_id);
 934                                 $data = ActivityPub\Transmitter::createNote($item);
 935                                 $object = JsonLD::compact($data);
 936                         }
 937
 938                         $id = JsonLD::fetchElement($object, '@id');
 939                         if (empty($id)) {
 940                                 Logger::info('Empty id');
 941                                 return false;
 942                         }
 943
 944                         if ($id != $object_id) {
 945                                 Logger::info('Fetched id differs from provided id', ['provided' => $object_id, 'fetched' => $id]);
 946                                 return false;
 947                         }
 948                 } else {
 949                         Logger::info('Using original object for url ' . $object_id);
 950                 }
 951
 952                 $type = JsonLD::fetchElement($object, '@type');
 953                 if (empty($type)) {
 954                         Logger::info('Empty type');
 955                         return false;
 956                 }
 957
 958                 // We currently don't handle 'pt:CacheFile', but with this step we avoid logging
 959                 if (in_array($type, self::CONTENT_TYPES) || ($type == 'pt:CacheFile')) {
 960                         $object_data = self::processObject($object);
 961
 962                         if (!empty($data)) {
 963                                 $object_data['raw'] = json_encode($data);
 964                         }
 965                         return $object_data;
 966                 }
 967
 968                 if ($type == 'as:Announce') {
 969                         $object_id = JsonLD::fetchElement($object, 'object', '@id');
 970                         if (empty($object_id) || !is_string($object_id)) {
 971                                 return false;
 972                         }
 973                         return self::fetchObject($object_id, [], false, $uid);
 974                 }
 975
 976                 Logger::info('Unhandled object type: ' . $type);
 977                 return false;
 978         }
 979
 980         /**
 981          * Converts the language element (Used by Peertube)
 982          *
 983          * @param array $languages
 984          * @return array Languages
 985          */
 986         public static function processLanguages(array $languages)
 987         {
 988                 if (empty($languages)) {
 989                         return [];
 990                 }
 991
 992                 $language_list = [];
 993
 994                 foreach ($languages as $language) {
 995                         if (!empty($language['_:identifier']) && !empty($language['as:name'])) {
 996                                 $language_list[$language['_:identifier']] = $language['as:name'];
 997                         }
 998                 }
 999                 return $language_list;
1000         }
1001
1002         /**
1003          * Convert tags from JSON-LD format into a simplified format
1004          *
1005          * @param array $tags Tags in JSON-LD format
1006          *
1007          * @return array with tags in a simplified format
1008          */
1009         public static function processTags(array $tags)
1010         {
1011                 $taglist = [];
1012
1013                 foreach ($tags as $tag) {
1014                         if (empty($tag)) {
1015                                 continue;
1016                         }
1017
1018                         $element = ['type' => str_replace('as:', '', JsonLD::fetchElement($tag, '@type')),
1019                                 'href' => JsonLD::fetchElement($tag, 'as:href', '@id'),
1020                                 'name' => JsonLD::fetchElement($tag, 'as:name', '@value')];
1021
1022                         if (empty($element['type'])) {
1023                                 continue;
1024                         }
1025
1026                         if (empty($element['href'])) {
1027                                 $element['href'] = $element['name'];
1028                         }
1029
1030                         $taglist[] = $element;
1031                 }
1032                 return $taglist;
1033         }
1034
1035         /**
1036          * Convert emojis from JSON-LD format into a simplified format
1037          *
1038          * @param array $emojis
1039          * @return array with emojis in a simplified format
1040          */
1041         private static function processEmojis(array $emojis)
1042         {
1043                 $emojilist = [];
1044
1045                 foreach ($emojis as $emoji) {
1046                         if (empty($emoji) || (JsonLD::fetchElement($emoji, '@type') != 'toot:Emoji') || empty($emoji['as:icon'])) {
1047                                 continue;
1048                         }
1049
1050                         $url = JsonLD::fetchElement($emoji['as:icon'], 'as:url', '@id');
1051                         $element = ['name' => JsonLD::fetchElement($emoji, 'as:name', '@value'),
1052                                 'href' => $url];
1053
1054                         $emojilist[] = $element;
1055                 }
1056
1057                 return $emojilist;
1058         }
1059
1060         /**
1061          * Convert attachments from JSON-LD format into a simplified format
1062          *
1063          * @param array $attachments Attachments in JSON-LD format
1064          *
1065          * @return array Attachments in a simplified format
1066          */
1067         private static function processAttachments(array $attachments)
1068         {
1069                 $attachlist = [];
1070
1071                 // Removes empty values
1072                 $attachments = array_filter($attachments);
1073
1074                 foreach ($attachments as $attachment) {
1075                         switch (JsonLD::fetchElement($attachment, '@type')) {
1076                                 case 'as:Page':
1077                                         $pageUrl = null;
1078                                         $pageImage = null;
1079
1080                                         $urls = JsonLD::fetchElementArray($attachment, 'as:url');
1081                                         foreach ($urls as $url) {
1082                                                 // Single scalar URL case
1083                                                 if (is_string($url)) {
1084                                                         $pageUrl = $url;
1085                                                         continue;
1086                                                 }
1087
1088                                                 $href = JsonLD::fetchElement($url, 'as:href', '@id');
1089                                                 $mediaType = JsonLD::fetchElement($url, 'as:mediaType', '@value');
1090                                                 if (Strings::startsWith($mediaType, 'image')) {
1091                                                         $pageImage = $href;
1092                                                 } else {
1093                                                         $pageUrl = $href;
1094                                                 }
1095                                         }
1096
1097                                         $attachlist[] = [
1098                                                 'type'  => 'link',
1099                                                 'title' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1100                                                 'desc'  => JsonLD::fetchElement($attachment, 'as:summary', '@value'),
1101                                                 'url'   => $pageUrl,
1102                                                 'image' => $pageImage,
1103                                         ];
1104                                         break;
1105                                 case 'as:Image':
1106                                         $mediaType = JsonLD::fetchElement($attachment, 'as:mediaType', '@value');
1107                                         $imageFullUrl = JsonLD::fetchElement($attachment, 'as:url', '@id');
1108                                         $imagePreviewUrl = null;
1109                                         // Multiple URLs?
1110                                         if (!$imageFullUrl && ($urls = JsonLD::fetchElementArray($attachment, 'as:url'))) {
1111                                                 $imageVariants = [];
1112                                                 $previewVariants = [];
1113                                                 foreach ($urls as $url) {
1114                                                         // Scalar URL, no discrimination possible
1115                                                         if (is_string($url)) {
1116                                                                 $imageFullUrl = $url;
1117                                                                 continue;
1118                                                         }
1119
1120                                                         // Not sure what to do with a different Link media type than the base Image, we skip
1121                                                         if ($mediaType != JsonLD::fetchElement($url, 'as:mediaType', '@value')) {
1122                                                                 continue;
1123                                                         }
1124
1125                                                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1126
1127                                                         // Default URL choice if no discriminating width is provided
1128                                                         $imageFullUrl = $href ?? $imageFullUrl;
1129
1130                                                         $width = intval(JsonLD::fetchElement($url, 'as:width', '@value') ?? 1);
1131
1132                                                         if ($href && $width) {
1133                                                                 $imageVariants[$width] = $href;
1134                                                                 // 632 is the ideal width for full screen frio posts, we compute the absolute distance to it
1135                                                                 $previewVariants[abs(632 - $width)] = $href;
1136                                                         }
1137                                                 }
1138
1139                                                 if ($imageVariants) {
1140                                                         // Taking the maximum size image
1141                                                         ksort($imageVariants);
1142                                                         $imageFullUrl = array_pop($imageVariants);
1143
1144                                                         // Taking the minimum number distance to the target distance
1145                                                         ksort($previewVariants);
1146                                                         $imagePreviewUrl = array_shift($previewVariants);
1147                                                 }
1148
1149                                                 unset($imageVariants);
1150                                                 unset($previewVariants);
1151                                         }
1152
1153                                         $attachlist[] = [
1154                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1155                                                 'mediaType' => $mediaType,
1156                                                 'name'  => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1157                                                 'url'   => $imageFullUrl,
1158                                                 'image' => $imagePreviewUrl !== $imageFullUrl ? $imagePreviewUrl : null,
1159                                         ];
1160                                         break;
1161                                 default:
1162                                         $attachlist[] = [
1163                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1164                                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType', '@value'),
1165                                                 'name' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1166                                                 'url' => JsonLD::fetchElement($attachment, 'as:url', '@id'),
1167                                                 'height' => JsonLD::fetchElement($attachment, 'as:height', '@value'),
1168                                                 'width' => JsonLD::fetchElement($attachment, 'as:width', '@value'),
1169                                                 'image' => JsonLD::fetchElement($attachment, 'as:image', '@id')
1170                                         ];
1171                         }
1172                 }
1173
1174                 return $attachlist;
1175         }
1176
1177         /**
1178          * Fetch the original source or content with the "language" Markdown or HTML
1179          *
1180          * @param array $object
1181          * @param array $object_data
1182          *
1183          * @return array
1184          * @throws \Exception
1185          */
1186         private static function getSource($object, $object_data)
1187         {
1188                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/bbcode');
1189                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1190                 if (!empty($object_data['source'])) {
1191                         return $object_data;
1192                 }
1193
1194                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/markdown');
1195                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1196                 if (!empty($object_data['source'])) {
1197                         $object_data['source'] = Markdown::toBBCode($object_data['source']);
1198                         return $object_data;
1199                 }
1200
1201                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/html');
1202                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1203                 if (!empty($object_data['source'])) {
1204                         $object_data['source'] = HTML::toBBCode($object_data['source']);
1205                         return $object_data;
1206                 }
1207
1208                 return $object_data;
1209         }
1210
1211         /**
1212          * Extracts a potential alternate URL from a list of additional URL elements
1213          *
1214          * @param array $urls
1215          * @return string
1216          */
1217         private static function extractAlternateUrl(array $urls): string
1218         {
1219                 $alternateUrl = '';
1220                 foreach ($urls as $key => $url) {
1221                         // Not a list but a single URL element
1222                         if (!is_numeric($key)) {
1223                                 continue;
1224                         }
1225
1226                         if (empty($url['@type']) || ($url['@type'] != 'as:Link')) {
1227                                 continue;
1228                         }
1229
1230                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1231                         if (empty($href)) {
1232                                 continue;
1233                         }
1234
1235                         $mediatype = JsonLD::fetchElement($url, 'as:mediaType');
1236                         if (empty($mediatype)) {
1237                                 continue;
1238                         }
1239
1240                         if ($mediatype == 'text/html') {
1241                                 $alternateUrl = $href;
1242                         }
1243                 }
1244
1245                 return $alternateUrl;
1246         }
1247
1248         /**
1249          * Check if the "as:url" element is an array with multiple links
1250          * This is the case with audio and video posts.
1251          * Then the links are added as attachments
1252          *
1253          * @param array $urls The object URL list
1254          * @return array an array of attachments
1255          */
1256         private static function processAttachmentUrls(array $urls): array
1257         {
1258                 $attachments = [];
1259                 foreach ($urls as $key => $url) {
1260                         // Not a list but a single URL element
1261                         if (!is_numeric($key)) {
1262                                 continue;
1263                         }
1264
1265                         if (empty($url['@type']) || ($url['@type'] != 'as:Link')) {
1266                                 continue;
1267                         }
1268
1269                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1270                         if (empty($href)) {
1271                                 continue;
1272                         }
1273
1274                         $mediatype = JsonLD::fetchElement($url, 'as:mediaType');
1275                         if (empty($mediatype)) {
1276                                 continue;
1277                         }
1278
1279                         $filetype = strtolower(substr($mediatype, 0, strpos($mediatype, '/')));
1280
1281                         if ($filetype == 'audio') {
1282                                 $attachments[] = ['type' => $filetype, 'mediaType' => $mediatype, 'url' => $href, 'height' => null, 'size' => null, 'name' => ''];
1283                         } elseif ($filetype == 'video') {
1284                                 $height = (int)JsonLD::fetchElement($url, 'as:height', '@value');
1285                                 // PeerTube audio-only track
1286                                 if ($height === 0) {
1287                                         continue;
1288                                 }
1289
1290                                 $size = (int)JsonLD::fetchElement($url, 'pt:size', '@value');
1291                                 $attachments[] = ['type' => $filetype, 'mediaType' => $mediatype, 'url' => $href, 'height' => $height, 'size' => $size, 'name' => ''];
1292                         } elseif (in_array($mediatype, ['application/x-bittorrent', 'application/x-bittorrent;x-scheme-handler/magnet'])) {
1293                                 $height = (int)JsonLD::fetchElement($url, 'as:height', '@value');
1294
1295                                 // For Torrent links we always store the highest resolution
1296                                 if (!empty($attachments[$mediatype]['height']) && ($height < $attachments[$mediatype]['height'])) {
1297                                         continue;
1298                                 }
1299
1300                                 $attachments[$mediatype] = ['type' => $mediatype, 'mediaType' => $mediatype, 'url' => $href, 'height' => $height, 'size' => null, 'name' => ''];
1301                         } elseif ($mediatype == 'application/x-mpegURL') {
1302                                 // PeerTube exception, actual video link is in the tags of this URL element
1303                                 $attachments = array_merge($attachments, self::processAttachmentUrls($url['as:tag']));
1304                         }
1305                 }
1306
1307                 return array_values($attachments);
1308         }
1309
1310         /**
1311          * Fetches data from the object part of an activity
1312          *
1313          * @param array $object
1314          *
1315          * @return array
1316          * @throws \Exception
1317          */
1318         private static function processObject($object)
1319         {
1320                 if (!JsonLD::fetchElement($object, '@id')) {
1321                         return false;
1322                 }
1323
1324                 $object_data = [];
1325                 $object_data['object_type'] = JsonLD::fetchElement($object, '@type');
1326                 $object_data['id'] = JsonLD::fetchElement($object, '@id');
1327                 $object_data['reply-to-id'] = JsonLD::fetchElement($object, 'as:inReplyTo', '@id');
1328
1329                 // An empty "id" field is translated to "./" by the compactor, so we have to check for this content
1330                 if (empty($object_data['reply-to-id']) || ($object_data['reply-to-id'] == './')) {
1331                         $object_data['reply-to-id'] = $object_data['id'];
1332                 } else {
1333                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
1334                         $replyToId = Item::getURIByLink($object_data['reply-to-id']);
1335                         if (!empty($replyToId) && ($object_data['reply-to-id'] != $replyToId)) {
1336                                 Logger::notice('Fix wrong reply-to', ['received' => $object_data['reply-to-id'], 'correct' => $replyToId]);
1337                                 $object_data['reply-to-id'] = $replyToId;
1338                         }
1339                 }
1340
1341                 $object_data['published'] = JsonLD::fetchElement($object, 'as:published', '@value');
1342                 $object_data['updated'] = JsonLD::fetchElement($object, 'as:updated', '@value');
1343
1344                 if (empty($object_data['updated'])) {
1345                         $object_data['updated'] = $object_data['published'];
1346                 }
1347
1348                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
1349                         $object_data['published'] = $object_data['updated'];
1350                 }
1351
1352                 $actor = JsonLD::fetchElement($object, 'as:attributedTo', '@id');
1353                 if (empty($actor)) {
1354                         $actor = JsonLD::fetchElement($object, 'as:actor', '@id');
1355                 }
1356
1357                 $location = JsonLD::fetchElement($object, 'as:location', 'as:name', '@type', 'as:Place');
1358                 $location = JsonLD::fetchElement($location, 'location', '@value');
1359                 if ($location) {
1360                         // Some AP software allow formatted text in post location, so we run all the text converters we have to boil
1361                         // down to HTML and then finally format to plaintext.
1362                         $location = Markdown::convert($location);
1363                         $location = BBCode::toPlaintext($location);
1364                 }
1365
1366                 $object_data['sc:identifier'] = JsonLD::fetchElement($object, 'sc:identifier', '@value');
1367                 $object_data['diaspora:guid'] = JsonLD::fetchElement($object, 'diaspora:guid', '@value');
1368                 $object_data['diaspora:comment'] = JsonLD::fetchElement($object, 'diaspora:comment', '@value');
1369                 $object_data['diaspora:like'] = JsonLD::fetchElement($object, 'diaspora:like', '@value');
1370                 $object_data['actor'] = $object_data['author'] = $actor;
1371                 $object_data['context'] = JsonLD::fetchElement($object, 'as:context', '@id');
1372                 $object_data['conversation'] = JsonLD::fetchElement($object, 'ostatus:conversation', '@id');
1373                 $object_data['sensitive'] = JsonLD::fetchElement($object, 'as:sensitive');
1374                 $object_data['name'] = JsonLD::fetchElement($object, 'as:name', '@value');
1375                 $object_data['summary'] = JsonLD::fetchElement($object, 'as:summary', '@value');
1376                 $object_data['content'] = JsonLD::fetchElement($object, 'as:content', '@value');
1377                 $object_data['mediatype'] = JsonLD::fetchElement($object, 'as:mediaType', '@value');
1378                 $object_data = self::getSource($object, $object_data);
1379                 $object_data['start-time'] = JsonLD::fetchElement($object, 'as:startTime', '@value');
1380                 $object_data['end-time'] = JsonLD::fetchElement($object, 'as:endTime', '@value');
1381                 $object_data['location'] = $location;
1382                 $object_data['latitude'] = JsonLD::fetchElement($object, 'as:location', 'as:latitude', '@type', 'as:Place');
1383                 $object_data['latitude'] = JsonLD::fetchElement($object_data, 'latitude', '@value');
1384                 $object_data['longitude'] = JsonLD::fetchElement($object, 'as:location', 'as:longitude', '@type', 'as:Place');
1385                 $object_data['longitude'] = JsonLD::fetchElement($object_data, 'longitude', '@value');
1386                 $object_data['attachments'] = self::processAttachments(JsonLD::fetchElementArray($object, 'as:attachment') ?? []);
1387                 $object_data['tags'] = self::processTags(JsonLD::fetchElementArray($object, 'as:tag') ?? []);
1388                 $object_data['emojis'] = self::processEmojis(JsonLD::fetchElementArray($object, 'as:tag', null, '@type', 'toot:Emoji') ?? []);
1389                 $object_data['languages'] = self::processLanguages(JsonLD::fetchElementArray($object, 'sc:inLanguage') ?? []);
1390                 $object_data['generator'] = JsonLD::fetchElement($object, 'as:generator', 'as:name', '@type', 'as:Application');
1391                 $object_data['generator'] = JsonLD::fetchElement($object_data, 'generator', '@value');
1392                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'as:url', '@id');
1393
1394                 // Special treatment for Hubzilla links
1395                 if (is_array($object_data['alternate-url'])) {
1396                         $object_data['alternate-url'] = JsonLD::fetchElement($object_data['alternate-url'], 'as:href', '@id');
1397
1398                         if (!is_string($object_data['alternate-url'])) {
1399                                 $object_data['alternate-url'] = JsonLD::fetchElement($object['as:url'], 'as:href', '@id');
1400                         }
1401                 }
1402
1403                 if (in_array($object_data['object_type'], ['as:Audio', 'as:Video'])) {
1404                         $object_data['alternate-url'] = self::extractAlternateUrl($object['as:url'] ?? []) ?: $object_data['alternate-url'];
1405                         $object_data['attachments'] = array_merge($object_data['attachments'], self::processAttachmentUrls($object['as:url'] ?? []));
1406                 }
1407
1408                 $receiverdata = self::getReceivers($object, $object_data['actor'], $object_data['tags'], true);
1409                 $receivers = $reception_types = [];
1410                 foreach ($receiverdata as $key => $data) {
1411                         $receivers[$key] = $data['uid'];
1412                         $reception_types[$data['uid']] = $data['type'] ?? 0;
1413                 }
1414
1415                 $object_data['receiver'] = $receivers;
1416                 $object_data['reception_type'] = $reception_types;
1417
1418                 $object_data['unlisted'] = in_array(-1, $object_data['receiver']);
1419                 unset($object_data['receiver'][-1]);
1420                 unset($object_data['reception_type'][-1]);
1421
1422                 // Common object data:
1423
1424                 // Unhandled
1425                 // @context, type, actor, signature, mediaType, duration, replies, icon
1426
1427                 // Also missing: (Defined in the standard, but currently unused)
1428                 // audience, preview, endTime, startTime, image
1429
1430                 // Data in Notes:
1431
1432                 // Unhandled
1433                 // contentMap, announcement_count, announcements, context_id, likes, like_count
1434                 // inReplyToStatusId, shares, quoteUrl, statusnetConversationId
1435
1436                 // Data in video:
1437
1438                 // To-Do?
1439                 // category, licence, language, commentsEnabled
1440
1441                 // Unhandled
1442                 // views, waitTranscoding, state, support, subtitleLanguage
1443                 // likes, dislikes, shares, comments
1444
1445                 return $object_data;
1446         }
1447 }