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