src/Protocol/ActivityPub/Receiver.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2020, Friendica
   4  *
   5  * @license GNU AGPL version 3 or any later version
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU Affero General Public License as
   9  * published by the Free Software Foundation, either version 3 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU Affero General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Affero General Public License
  18  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  19  *
  20  */
  21
  22 namespace Friendica\Protocol\ActivityPub;
  23
  24 use Friendica\Content\Text\BBCode;
  25 use Friendica\Database\DBA;
  26 use Friendica\Content\Text\HTML;
  27 use Friendica\Content\Text\Markdown;
  28 use Friendica\Core\Logger;
  29 use Friendica\Core\Protocol;
  30 use Friendica\Model\Contact;
  31 use Friendica\Model\APContact;
  32 use Friendica\Model\Item;
  33 use Friendica\Model\User;
  34 use Friendica\Protocol\Activity;
  35 use Friendica\Protocol\ActivityPub;
  36 use Friendica\Util\HTTPSignature;
  37 use Friendica\Util\JsonLD;
  38 use Friendica\Util\LDSignature;
  39 use Friendica\Util\Strings;
  40
  41 /**
  42  * ActivityPub Receiver Protocol class
  43  *
  44  * To-Do:
  45  * @todo Undo Announce
  46  *
  47  * Check what this is meant to do:
  48  * - Add
  49  * - Block
  50  * - Flag
  51  * - Remove
  52  * - Undo Block
  53  */
  54 class Receiver
  55 {
  56         const PUBLIC_COLLECTION = 'as:Public';
  57         const ACCOUNT_TYPES = ['as:Person', 'as:Organization', 'as:Service', 'as:Group', 'as:Application'];
  58         const CONTENT_TYPES = ['as:Note', 'as:Article', 'as:Video', 'as:Image', 'as:Event', 'as:Audio'];
  59         const ACTIVITY_TYPES = ['as:Like', 'as:Dislike', 'as:Accept', 'as:Reject', 'as:TentativeAccept'];
  60
  61         const TARGET_UNKNOWN = 0;
  62         const TARGET_TO = 1;
  63         const TARGET_CC = 2;
  64         const TARGET_BTO = 3;
  65         const TARGET_BCC = 4;
  66         const TARGET_FOLLOWER = 5;
  67         const TARGET_ANSWER = 6;
  68         const TARGET_GLOBAL = 7;
  69
  70         /**
  71          * Checks if the web request is done for the AP protocol
  72          *
  73          * @return bool is it AP?
  74          */
  75         public static function isRequest()
  76         {
  77                 return stristr($_SERVER['HTTP_ACCEPT'] ?? '', 'application/activity+json') ||
  78                         stristr($_SERVER['HTTP_ACCEPT'] ?? '', 'application/ld+json');
  79         }
  80
  81         /**
  82          * Checks incoming message from the inbox
  83          *
  84          * @param         $body
  85          * @param         $header
  86          * @param integer $uid User ID
  87          * @throws \Exception
  88          */
  89         public static function processInbox($body, $header, $uid)
  90         {
  91                 $activity = json_decode($body, true);
  92                 if (empty($activity)) {
  93                         Logger::warning('Invalid body.');
  94                         return;
  95                 }
  96
  97                 $ldactivity = JsonLD::compact($activity);
  98
  99                 $actor = JsonLD::fetchElement($ldactivity, 'as:actor', '@id');
 100
 101                 $apcontact = APContact::getByURL($actor);
 102                 if (!empty($apcontact) && ($apcontact['type'] == 'Application') && ($apcontact['nick'] == 'relay')) {
 103                         self::processRelayPost($ldactivity);
 104                         return;
 105                 }
 106
 107                 $http_signer = HTTPSignature::getSigner($body, $header);
 108                 if (empty($http_signer)) {
 109                         Logger::warning('Invalid HTTP signature, message will be discarded.');
 110                         return;
 111                 } else {
 112                         Logger::info('Valid HTTP signature', ['signer' => $http_signer]);
 113                 }
 114
 115                 $signer = [$http_signer];
 116
 117                 Logger::info('Message for user ' . $uid . ' is from actor ' . $actor);
 118
 119                 if (LDSignature::isSigned($activity)) {
 120                         $ld_signer = LDSignature::getSigner($activity);
 121                         if (empty($ld_signer)) {
 122                                 Logger::log('Invalid JSON-LD signature from ' . $actor, Logger::DEBUG);
 123                         } elseif ($ld_signer != $http_signer) {
 124                                 $signer[] = $ld_signer;
 125                         }
 126                         if (!empty($ld_signer && ($actor == $http_signer))) {
 127                                 Logger::log('The HTTP and the JSON-LD signature belong to ' . $ld_signer, Logger::DEBUG);
 128                                 $trust_source = true;
 129                         } elseif (!empty($ld_signer)) {
 130                                 Logger::log('JSON-LD signature is signed by ' . $ld_signer, Logger::DEBUG);
 131                                 $trust_source = true;
 132                         } elseif ($actor == $http_signer) {
 133                                 Logger::log('Bad JSON-LD signature, but HTTP signer fits the actor.', Logger::DEBUG);
 134                                 $trust_source = true;
 135                         } else {
 136                                 Logger::log('Invalid JSON-LD signature and the HTTP signer is different.', Logger::DEBUG);
 137                                 $trust_source = false;
 138                         }
 139                 } elseif ($actor == $http_signer) {
 140                         Logger::log('Trusting post without JSON-LD signature, The actor fits the HTTP signer.', Logger::DEBUG);
 141                         $trust_source = true;
 142                 } else {
 143                         Logger::log('No JSON-LD signature, different actor.', Logger::DEBUG);
 144                         $trust_source = false;
 145                 }
 146
 147                 self::processActivity($ldactivity, $body, $uid, $trust_source, true, $signer);
 148         }
 149
 150         /**
 151          * Process incoming posts from relays
 152          *
 153          * @param array $activity
 154          * @return void
 155          */
 156         private static function processRelayPost(array $activity)
 157         {
 158                 $type = JsonLD::fetchElement($activity, '@type');
 159                 if (!$type) {
 160                         Logger::info('Empty type', ['activity' => $activity]);
 161                         return;
 162                 }
 163
 164                 if ($type != 'as:Announce') {
 165                         Logger::info('Not an announcement', ['activity' => $activity]);
 166                         return;
 167                 }
 168
 169                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 170                 if (empty($object_id)) {
 171                         Logger::info('No object id found', ['activity' => $activity]);
 172                         return;
 173                 }
 174
 175                 Logger::info('Got relayed message id', ['id' => $object_id]);
 176
 177                 $item_id = Item::searchByLink($object_id);
 178                 if ($item_id) {
 179                         Logger::info('Relayed message already exists', ['id' => $object_id, 'item' => $item_id]);
 180                         return;
 181                 }
 182
 183                 Processor::fetchMissingActivity($object_id);
 184         }
 185
 186         /**
 187          * Fetches the object type for a given object id
 188          *
 189          * @param array   $activity
 190          * @param string  $object_id Object ID of the the provided object
 191          * @param integer $uid       User ID
 192          *
 193          * @return string with object type
 194          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 195          * @throws \ImagickException
 196          */
 197         private static function fetchObjectType($activity, $object_id, $uid = 0)
 198         {
 199                 if (!empty($activity['as:object'])) {
 200                         $object_type = JsonLD::fetchElement($activity['as:object'], '@type');
 201                         if (!empty($object_type)) {
 202                                 return $object_type;
 203                         }
 204                 }
 205
 206                 if (Item::exists(['uri' => $object_id, 'gravity' => [GRAVITY_PARENT, GRAVITY_COMMENT]])) {
 207                         // We just assume "note" since it doesn't make a difference for the further processing
 208                         return 'as:Note';
 209                 }
 210
 211                 $profile = APContact::getByURL($object_id);
 212                 if (!empty($profile['type'])) {
 213                         return 'as:' . $profile['type'];
 214                 }
 215
 216                 $data = ActivityPub::fetchContent($object_id, $uid);
 217                 if (!empty($data)) {
 218                         $object = JsonLD::compact($data);
 219                         $type = JsonLD::fetchElement($object, '@type');
 220                         if (!empty($type)) {
 221                                 return $type;
 222                         }
 223                 }
 224
 225                 return null;
 226         }
 227
 228         /**
 229          * Prepare the object array
 230          *
 231          * @param array   $activity     Array with activity data
 232          * @param integer $uid          User ID
 233          * @param boolean $push         Message had been pushed to our system
 234          * @param boolean $trust_source Do we trust the source?
 235          *
 236          * @return array with object data
 237          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 238          * @throws \ImagickException
 239          */
 240         public static function prepareObjectData($activity, $uid, $push, &$trust_source)
 241         {
 242                 $id = JsonLD::fetchElement($activity, '@id');
 243                 if (!empty($id) && !$trust_source) {
 244                         $fetched_activity = ActivityPub::fetchContent($id, $uid ?? 0);
 245                         if (!empty($fetched_activity)) {
 246                                 $object = JsonLD::compact($fetched_activity);
 247                                 $fetched_id = JsonLD::fetchElement($object, '@id');
 248                                 if ($fetched_id == $id) {
 249                                         Logger::info('Activity had been fetched successfully', ['id' => $id]);
 250                                         $trust_source = true;
 251                                         $activity = $object;
 252                                 } else {
 253                                         Logger::info('Activity id is not equal', ['id' => $id, 'fetched' => $fetched_id]);
 254                                 }
 255                         } else {
 256                                 Logger::info('Activity could not been fetched', ['id' => $id]);
 257                         }
 258                 }
 259
 260                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 261                 if (empty($actor)) {
 262                         Logger::info('Empty actor', ['activity' => $activity]);
 263                         return [];
 264                 }
 265
 266                 $type = JsonLD::fetchElement($activity, '@type');
 267
 268                 // Fetch all receivers from to, cc, bto and bcc
 269                 $receiverdata = self::getReceivers($activity, $actor);
 270                 $receivers = $reception_types = [];
 271                 foreach ($receiverdata as $key => $data) {
 272                         $receivers[$key] = $data['uid'];
 273                         $reception_types[$data['uid']] = $data['type'] ?? 0;
 274                 }
 275
 276                 // When it is a delivery to a personal inbox we add that user to the receivers
 277                 if (!empty($uid)) {
 278                         $additional = ['uid:' . $uid => $uid];
 279                         $receivers = array_merge($receivers, $additional);
 280                         if (empty($reception_types[$uid]) || in_array($reception_types[$uid], [self::TARGET_UNKNOWN, self::TARGET_FOLLOWER, self::TARGET_ANSWER, self::TARGET_GLOBAL])) {
 281                                 $reception_types[$uid] = self::TARGET_BCC;
 282                         }
 283                 } else {
 284                         // We possibly need some user to fetch private content,
 285                         // so we fetch the first out ot the list.
 286                         $uid = self::getFirstUserFromReceivers($receivers);
 287                 }
 288
 289                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 290                 if (empty($object_id)) {
 291                         Logger::log('No object found', Logger::DEBUG);
 292                         return [];
 293                 }
 294
 295                 if (!is_string($object_id)) {
 296                         Logger::info('Invalid object id', ['object' => $object_id]);
 297                         return [];
 298                 }
 299
 300                 $object_type = self::fetchObjectType($activity, $object_id, $uid);
 301
 302                 // Fetch the content only on activities where this matters
 303                 if (in_array($type, ['as:Create', 'as:Update', 'as:Announce'])) {
 304                         // Always fetch on "Announce"
 305                         $object_data = self::fetchObject($object_id, $activity['as:object'], $trust_source && ($type != 'as:Announce'), $uid);
 306                         if (empty($object_data)) {
 307                                 Logger::log("Object data couldn't be processed", Logger::DEBUG);
 308                                 return [];
 309                         }
 310
 311                         $object_data['object_id'] = $object_id;
 312
 313                         if ($type == 'as:Announce') {
 314                                 $object_data['push'] = false;
 315                         } else {
 316                                 $object_data['push'] = $push;
 317                         }
 318
 319                         // Test if it is an answer to a mail
 320                         if (DBA::exists('mail', ['uri' => $object_data['reply-to-id']])) {
 321                                 $object_data['directmessage'] = true;
 322                         } else {
 323                                 $object_data['directmessage'] = JsonLD::fetchElement($activity, 'litepub:directMessage');
 324                         }
 325                 } elseif (in_array($type, array_merge(self::ACTIVITY_TYPES, ['as:Follow'])) && in_array($object_type, self::CONTENT_TYPES)) {
 326                         // Create a mostly empty array out of the activity data (instead of the object).
 327                         // This way we later don't have to check for the existence of ech individual array element.
 328                         $object_data = self::processObject($activity);
 329                         $object_data['name'] = $type;
 330                         $object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 331                         $object_data['object_id'] = $object_id;
 332                         $object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
 333                 } elseif (in_array($type, ['as:Add'])) {
 334                         $object_data = [];
 335                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 336                         $object_data['target_id'] = JsonLD::fetchElement($activity, 'as:target', '@id');
 337                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 338                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 339                         $object_data['object_content'] = JsonLD::fetchElement($activity['as:object'], 'as:content', '@type');
 340                 } else {
 341                         $object_data = [];
 342                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 343                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 344                         $object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor', '@id');
 345                         $object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
 346                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 347
 348                         // An Undo is done on the object of an object, so we need that type as well
 349                         if (($type == 'as:Undo') && !empty($object_data['object_object'])) {
 350                                 $object_data['object_object_type'] = self::fetchObjectType([], $object_data['object_object'], $uid);
 351                         }
 352                 }
 353
 354                 $object_data = self::addActivityFields($object_data, $activity);
 355
 356                 if (empty($object_data['object_type'])) {
 357                         $object_data['object_type'] = $object_type;
 358                 }
 359
 360                 $object_data['type'] = $type;
 361                 $object_data['actor'] = $actor;
 362                 $object_data['item_receiver'] = $receivers;
 363                 $object_data['receiver'] = array_merge($object_data['receiver'] ?? [], $receivers);
 364                 $object_data['reception_type'] = array_merge($object_data['reception_type'] ?? [], $reception_types);
 365
 366                 $author = $object_data['author'] ?? $actor;
 367                 if (!empty($author) && !empty($object_data['id'])) {
 368                         $author_host = parse_url($author, PHP_URL_HOST);
 369                         $id_host = parse_url($object_data['id'], PHP_URL_HOST);
 370                         if ($author_host == $id_host) {
 371                                 Logger::info('Valid hosts', ['type' => $type, 'host' => $id_host]);
 372                         } else {
 373                                 Logger::notice('Differing hosts on author and id', ['type' => $type, 'author' => $author_host, 'id' => $id_host]);
 374                                 $trust_source = false;
 375                         }
 376                 }
 377
 378                 Logger::log('Processing ' . $object_data['type'] . ' ' . $object_data['object_type'] . ' ' . $object_data['id'], Logger::DEBUG);
 379
 380                 return $object_data;
 381         }
 382
 383         /**
 384          * Fetches the first user id from the receiver array
 385          *
 386          * @param array $receivers Array with receivers
 387          * @return integer user id;
 388          */
 389         public static function getFirstUserFromReceivers($receivers)
 390         {
 391                 foreach ($receivers as $receiver) {
 392                         if (!empty($receiver)) {
 393                                 return $receiver;
 394                         }
 395                 }
 396                 return 0;
 397         }
 398
 399         /**
 400          * Processes the activity object
 401          *
 402          * @param array   $activity     Array with activity data
 403          * @param string  $body
 404          * @param integer $uid          User ID
 405          * @param boolean $trust_source Do we trust the source?
 406          * @param boolean $push         Message had been pushed to our system
 407          * @throws \Exception
 408          */
 409         public static function processActivity($activity, string $body = '', int $uid = null, bool $trust_source = false, bool $push = false, array $signer = [])
 410         {
 411                 $type = JsonLD::fetchElement($activity, '@type');
 412                 if (!$type) {
 413                         Logger::info('Empty type', ['activity' => $activity]);
 414                         return;
 415                 }
 416
 417                 if (!JsonLD::fetchElement($activity, 'as:object', '@id')) {
 418                         Logger::info('Empty object', ['activity' => $activity]);
 419                         return;
 420                 }
 421
 422                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 423                 if (empty($actor)) {
 424                         Logger::info('Empty actor', ['activity' => $activity]);
 425                         return;
 426                 }
 427
 428                 if (is_array($activity['as:object'])) {
 429                         $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
 430                 } else {
 431                         $attributed_to = '';
 432                 }
 433
 434                 // Test the provided signatures against the actor and "attributedTo"
 435                 if ($trust_source) {
 436                         if (!empty($attributed_to) && !empty($actor)) {
 437                                 $trust_source = (in_array($actor, $signer) && in_array($attributed_to, $signer));
 438                         } else {
 439                                 $trust_source = in_array($actor, $signer);
 440                         }
 441                 }
 442
 443                 // $trust_source is called by reference and is set to true if the content was retrieved successfully
 444                 $object_data = self::prepareObjectData($activity, $uid, $push, $trust_source);
 445                 if (empty($object_data)) {
 446                         Logger::info('No object data found', ['activity' => $activity]);
 447                         return;
 448                 }
 449
 450                 if (!$trust_source) {
 451                         Logger::info('Activity trust could not be achieved.',  ['id' => $object_data['object_id'], 'type' => $type, 'signer' => $signer, 'actor' => $actor, 'attributedTo' => $attributed_to]);
 452                         return;
 453                 }
 454
 455                 if (!empty($body) && empty($object_data['raw'])) {
 456                         $object_data['raw'] = $body;
 457                 }
 458
 459                 // Internal flag for thread completion. See Processor.php
 460                 if (!empty($activity['thread-completion'])) {
 461                         $object_data['thread-completion'] = $activity['thread-completion'];
 462                 }
 463
 464                 switch ($type) {
 465                         case 'as:Create':
 466                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 467                                         $item = ActivityPub\Processor::createItem($object_data);
 468                                         ActivityPub\Processor::postItem($object_data, $item);
 469                                 }
 470                                 break;
 471
 472                         case 'as:Add':
 473                                 if ($object_data['object_type'] == 'as:tag') {
 474                                         ActivityPub\Processor::addTag($object_data);
 475                                 }
 476                                 break;
 477
 478                         case 'as:Announce':
 479                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 480                                         $object_data['thread-completion'] = true;
 481
 482                                         $item = ActivityPub\Processor::createItem($object_data);
 483                                         $item['post-type'] = Item::PT_ANNOUNCEMENT;
 484                                         ActivityPub\Processor::postItem($object_data, $item);
 485
 486                                         $announce_object_data = self::processObject($activity);
 487                                         $announce_object_data['name'] = $type;
 488                                         $announce_object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 489                                         $announce_object_data['object_id'] = $object_data['object_id'];
 490                                         $announce_object_data['object_type'] = $object_data['object_type'];
 491                                         $announce_object_data['push'] = $push;
 492
 493                                         if (!empty($body)) {
 494                                                 $announce_object_data['raw'] = $body;
 495                                         }
 496
 497                                         ActivityPub\Processor::createActivity($announce_object_data, Activity::ANNOUNCE);
 498                                 }
 499                                 break;
 500
 501                         case 'as:Like':
 502                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 503                                         ActivityPub\Processor::createActivity($object_data, Activity::LIKE);
 504                                 }
 505                                 break;
 506
 507                         case 'as:Dislike':
 508                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 509                                         ActivityPub\Processor::createActivity($object_data, Activity::DISLIKE);
 510                                 }
 511                                 break;
 512
 513                         case 'as:TentativeAccept':
 514                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 515                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDMAYBE);
 516                                 }
 517                                 break;
 518
 519                         case 'as:Update':
 520                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 521                                         ActivityPub\Processor::updateItem($object_data);
 522                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 523                                         ActivityPub\Processor::updatePerson($object_data);
 524                                 }
 525                                 break;
 526
 527                         case 'as:Delete':
 528                                 if ($object_data['object_type'] == 'as:Tombstone') {
 529                                         ActivityPub\Processor::deleteItem($object_data);
 530                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 531                                         ActivityPub\Processor::deletePerson($object_data);
 532                                 }
 533                                 break;
 534
 535                         case 'as:Follow':
 536                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 537                                         ActivityPub\Processor::followUser($object_data);
 538                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 539                                         $object_data['reply-to-id'] = $object_data['object_id'];
 540                                         ActivityPub\Processor::createActivity($object_data, Activity::FOLLOW);
 541                                 }
 542                                 break;
 543
 544                         case 'as:Accept':
 545                                 if ($object_data['object_type'] == 'as:Follow') {
 546                                         ActivityPub\Processor::acceptFollowUser($object_data);
 547                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 548                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTEND);
 549                                 }
 550                                 break;
 551
 552                         case 'as:Reject':
 553                                 if ($object_data['object_type'] == 'as:Follow') {
 554                                         ActivityPub\Processor::rejectFollowUser($object_data);
 555                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 556                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDNO);
 557                                 }
 558                                 break;
 559
 560                         case 'as:Undo':
 561                                 if (($object_data['object_type'] == 'as:Follow') &&
 562                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 563                                         ActivityPub\Processor::undoFollowUser($object_data);
 564                                 } elseif (($object_data['object_type'] == 'as:Accept') &&
 565                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 566                                         ActivityPub\Processor::rejectFollowUser($object_data);
 567                                 } elseif (in_array($object_data['object_type'], self::ACTIVITY_TYPES) &&
 568                                         in_array($object_data['object_object_type'], self::CONTENT_TYPES)) {
 569                                         ActivityPub\Processor::undoActivity($object_data);
 570                                 }
 571                                 break;
 572
 573                         default:
 574                                 Logger::log('Unknown activity: ' . $type . ' ' . $object_data['object_type'], Logger::DEBUG);
 575                                 break;
 576                 }
 577         }
 578
 579         /**
 580          * Fetch the receiver list from an activity array
 581          *
 582          * @param array   $activity
 583          * @param string  $actor
 584          * @param array   $tags
 585          * @param boolean $fetch_unlisted
 586          *
 587          * @return array with receivers (user id)
 588          * @throws \Exception
 589          */
 590         private static function getReceivers($activity, $actor, $tags = [], $fetch_unlisted = false)
 591         {
 592                 $reply = $receivers = [];
 593
 594                 // When it is an answer, we inherite the receivers from the parent
 595                 $replyto = JsonLD::fetchElement($activity, 'as:inReplyTo', '@id');
 596                 if (!empty($replyto)) {
 597                         $reply = [$replyto];
 598
 599                         // Fix possibly wrong item URI (could be an answer to a plink uri)
 600                         $fixedReplyTo = Item::getURIByLink($replyto);
 601                         if (!empty($fixedReplyTo)) {
 602                                 $reply[] = $fixedReplyTo;
 603                         }
 604                 }
 605
 606                 // Fetch all posts that refer to the object id
 607                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 608                 if (!empty($object_id)) {
 609                         $reply[] = $object_id;
 610                 }
 611
 612                 if (!empty($reply)) {
 613                         $parents = Item::select(['uid'], ['uri' => $reply]);
 614                         while ($parent = Item::fetch($parents)) {
 615                                 $receivers['uid:' . $parent['uid']] = ['uid' => $parent['uid'], 'type' => self::TARGET_ANSWER];
 616                         }
 617                 }
 618
 619                 if (!empty($actor)) {
 620                         $profile = APContact::getByURL($actor);
 621                         $followers = $profile['followers'] ?? '';
 622
 623                         Logger::log('Actor: ' . $actor . ' - Followers: ' . $followers, Logger::DEBUG);
 624                 } else {
 625                         Logger::info('Empty actor', ['activity' => $activity]);
 626                         $followers = '';
 627                 }
 628
 629                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
 630                         $receiver_list = JsonLD::fetchElementArray($activity, $element, '@id');
 631                         if (empty($receiver_list)) {
 632                                 continue;
 633                         }
 634
 635                         foreach ($receiver_list as $receiver) {
 636                                 if ($receiver == self::PUBLIC_COLLECTION) {
 637                                         $receivers['uid:0'] = ['uid' => 0, 'type' => self::TARGET_GLOBAL];
 638                                 }
 639
 640                                 // Add receiver "-1" for unlisted posts
 641                                 if ($fetch_unlisted && ($receiver == self::PUBLIC_COLLECTION) && ($element == 'as:cc')) {
 642                                         $receivers['uid:-1'] = ['uid' => -1, 'type' => self::TARGET_GLOBAL];
 643                                 }
 644
 645                                 // Fetch the receivers for the public and the followers collection
 646                                 if (in_array($receiver, [$followers, self::PUBLIC_COLLECTION]) && !empty($actor)) {
 647                                         $receivers = self::getReceiverForActor($actor, $tags, $receivers);
 648                                         continue;
 649                                 }
 650
 651                                 // Fetching all directly addressed receivers
 652                                 $condition = ['self' => true, 'nurl' => Strings::normaliseLink($receiver)];
 653                                 $contact = DBA::selectFirst('contact', ['uid', 'contact-type'], $condition);
 654                                 if (!DBA::isResult($contact)) {
 655                                         continue;
 656                                 }
 657
 658                                 // Check if the potential receiver is following the actor
 659                                 // Exception: The receiver is targetted via "to" or this is a comment
 660                                 if ((($element != 'as:to') && empty($replyto)) || ($contact['contact-type'] == Contact::TYPE_COMMUNITY)) {
 661                                         $networks = Protocol::FEDERATED;
 662                                         $condition = ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
 663                                                 'network' => $networks, 'archive' => false, 'pending' => false, 'uid' => $contact['uid']];
 664
 665                                         // Forum posts are only accepted from forum contacts
 666                                         if ($contact['contact-type'] == Contact::TYPE_COMMUNITY) {
 667                                                 $condition['rel'] = [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER];
 668                                         }
 669
 670                                         if (!DBA::exists('contact', $condition)) {
 671                                                 continue;
 672                                         }
 673                                 }
 674
 675                                 $type = $receivers['uid:' . $contact['uid']]['type'] ?? self::TARGET_UNKNOWN;
 676                                 if (in_array($type, [self::TARGET_UNKNOWN, self::TARGET_FOLLOWER, self::TARGET_ANSWER, self::TARGET_GLOBAL])) {
 677                                         switch ($element) {
 678                                                 case 'as:to':
 679                                                         $type = self::TARGET_TO;
 680                                                         break;
 681                                                 case 'as:cc':
 682                                                         $type = self::TARGET_CC;
 683                                                         break;
 684                                                 case 'as:bto':
 685                                                         $type = self::TARGET_BTO;
 686                                                         break;
 687                                                 case 'as:bcc':
 688                                                         $type = self::TARGET_BCC;
 689                                                         break;
 690                                         }
 691
 692                                         $receivers['uid:' . $contact['uid']] = ['uid' => $contact['uid'], 'type' => $type];
 693                                 }
 694                         }
 695                 }
 696
 697                 self::switchContacts($receivers, $actor);
 698
 699                 return $receivers;
 700         }
 701
 702         /**
 703          * Fetch the receiver list of a given actor
 704          *
 705          * @param string $actor
 706          * @param array  $tags
 707          *
 708          * @return array with receivers (user id)
 709          * @throws \Exception
 710          */
 711         private static function getReceiverForActor($actor, $tags, $receivers)
 712         {
 713                 $basecondition = ['rel' => [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER],
 714                         'network' => Protocol::FEDERATED, 'archive' => false, 'pending' => false];
 715
 716                 $condition = DBA::mergeConditions($basecondition, ['nurl' => Strings::normaliseLink($actor)]);
 717                 $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
 718                 while ($contact = DBA::fetch($contacts)) {
 719                         if (empty($receivers['uid:' . $contact['uid']]) && self::isValidReceiverForActor($contact, $actor, $tags)) {
 720                                 $receivers['uid:' . $contact['uid']] = ['uid' => $contact['uid'], 'type' => self::TARGET_FOLLOWER];
 721                         }
 722                 }
 723                 DBA::close($contacts);
 724
 725                 // The queries are split because of performance issues
 726                 $condition = DBA::mergeConditions($basecondition, ["`alias` IN (?, ?)", Strings::normaliseLink($actor), $actor]);
 727                 $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
 728                 while ($contact = DBA::fetch($contacts)) {
 729                         if (empty($receivers['uid:' . $contact['uid']]) && self::isValidReceiverForActor($contact, $actor, $tags)) {
 730                                 $receivers['uid:' . $contact['uid']] = ['uid' => $contact['uid'], 'type' => self::TARGET_FOLLOWER];
 731                         }
 732                 }
 733                 DBA::close($contacts);
 734                 return $receivers;
 735         }
 736
 737         /**
 738          * Tests if the contact is a valid receiver for this actor
 739          *
 740          * @param array  $contact
 741          * @param string $actor
 742          * @param array  $tags
 743          *
 744          * @return bool with receivers (user id)
 745          * @throws \Exception
 746          */
 747         private static function isValidReceiverForActor($contact, $actor, $tags)
 748         {
 749                 // Public contacts are no valid receiver
 750                 if ($contact['uid'] == 0) {
 751                         return false;
 752                 }
 753
 754                 // Are we following the contact? Then this is a valid receiver
 755                 if (in_array($contact['rel'], [Contact::SHARING, Contact::FRIEND])) {
 756                         return true;
 757                 }
 758
 759                 // When the possible receiver isn't a community, then it is no valid receiver
 760                 $owner = User::getOwnerDataById($contact['uid']);
 761                 if (empty($owner) || ($owner['contact-type'] != Contact::TYPE_COMMUNITY)) {
 762                         return false;
 763                 }
 764
 765                 // Is the community account tagged?
 766                 foreach ($tags as $tag) {
 767                         if ($tag['type'] != 'Mention') {
 768                                 continue;
 769                         }
 770
 771                         if ($tag['href'] == $owner['url']) {
 772                                 return true;
 773                         }
 774                 }
 775
 776                 return false;
 777         }
 778
 779         /**
 780          * Switches existing contacts to ActivityPub
 781          *
 782          * @param integer $cid Contact ID
 783          * @param integer $uid User ID
 784          * @param string  $url Profile URL
 785          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 786          * @throws \ImagickException
 787          */
 788         public static function switchContact($cid, $uid, $url)
 789         {
 790                 if (DBA::exists('contact', ['id' => $cid, 'network' => Protocol::ACTIVITYPUB])) {
 791                         Logger::info('Contact is already ActivityPub', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
 792                         return;
 793                 }
 794
 795                 if (Contact::updateFromProbe($cid)) {
 796                         Logger::info('Update was successful', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
 797                 }
 798
 799                 // Send a new follow request to be sure that the connection still exists
 800                 if (($uid != 0) && DBA::exists('contact', ['id' => $cid, 'rel' => [Contact::SHARING, Contact::FRIEND], 'network' => Protocol::ACTIVITYPUB])) {
 801                         Logger::info('Contact had been switched to ActivityPub. Sending a new follow request.', ['uid' => $uid, 'url' => $url]);
 802                         ActivityPub\Transmitter::sendActivity('Follow', $url, $uid);
 803                 }
 804         }
 805
 806         /**
 807          *
 808          *
 809          * @param $receivers
 810          * @param $actor
 811          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 812          * @throws \ImagickException
 813          */
 814         private static function switchContacts($receivers, $actor)
 815         {
 816                 if (empty($actor)) {
 817                         return;
 818                 }
 819
 820                 foreach ($receivers as $receiver) {
 821                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver['uid'], 'network' => Protocol::OSTATUS, 'nurl' => Strings::normaliseLink($actor)]);
 822                         if (DBA::isResult($contact)) {
 823                                 self::switchContact($contact['id'], $receiver['uid'], $actor);
 824                         }
 825
 826                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver['uid'], 'network' => Protocol::OSTATUS, 'alias' => [Strings::normaliseLink($actor), $actor]]);
 827                         if (DBA::isResult($contact)) {
 828                                 self::switchContact($contact['id'], $receiver['uid'], $actor);
 829                         }
 830                 }
 831         }
 832
 833         /**
 834          *
 835          *
 836          * @param       $object_data
 837          * @param array $activity
 838          *
 839          * @return mixed
 840          */
 841         private static function addActivityFields($object_data, $activity)
 842         {
 843                 if (!empty($activity['published']) && empty($object_data['published'])) {
 844                         $object_data['published'] = JsonLD::fetchElement($activity, 'as:published', '@value');
 845                 }
 846
 847                 if (!empty($activity['diaspora:guid']) && empty($object_data['diaspora:guid'])) {
 848                         $object_data['diaspora:guid'] = JsonLD::fetchElement($activity, 'diaspora:guid', '@value');
 849                 }
 850
 851                 $object_data['service'] = JsonLD::fetchElement($activity, 'as:instrument', 'as:name', '@type', 'as:Service');
 852                 $object_data['service'] = JsonLD::fetchElement($object_data, 'service', '@value');
 853
 854                 if (!empty($object_data['object_id'])) {
 855                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
 856                         $objectId = Item::getURIByLink($object_data['object_id']);
 857                         if (!empty($objectId) && ($object_data['object_id'] != $objectId)) {
 858                                 Logger::notice('Fix wrong object-id', ['received' => $object_data['object_id'], 'correct' => $objectId]);
 859                                 $object_data['object_id'] = $objectId;
 860                         }
 861                 }
 862
 863                 return $object_data;
 864         }
 865
 866         /**
 867          * Fetches the object data from external ressources if needed
 868          *
 869          * @param string  $object_id    Object ID of the the provided object
 870          * @param array   $object       The provided object array
 871          * @param boolean $trust_source Do we trust the provided object?
 872          * @param integer $uid          User ID for the signature that we use to fetch data
 873          *
 874          * @return array|false with trusted and valid object data
 875          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 876          * @throws \ImagickException
 877          */
 878         private static function fetchObject(string $object_id, array $object = [], bool $trust_source = false, int $uid = 0)
 879         {
 880                 // By fetching the type we check if the object is complete.
 881                 $type = JsonLD::fetchElement($object, '@type');
 882
 883                 if (!$trust_source || empty($type)) {
 884                         $data = ActivityPub::fetchContent($object_id, $uid);
 885                         if (!empty($data)) {
 886                                 $object = JsonLD::compact($data);
 887                                 Logger::log('Fetched content for ' . $object_id, Logger::DEBUG);
 888                         } else {
 889                                 Logger::log('Empty content for ' . $object_id . ', check if content is available locally.', Logger::DEBUG);
 890
 891                                 $item = Item::selectFirst([], ['uri' => $object_id]);
 892                                 if (!DBA::isResult($item)) {
 893                                         Logger::log('Object with url ' . $object_id . ' was not found locally.', Logger::DEBUG);
 894                                         return false;
 895                                 }
 896                                 Logger::log('Using already stored item for url ' . $object_id, Logger::DEBUG);
 897                                 $data = ActivityPub\Transmitter::createNote($item);
 898                                 $object = JsonLD::compact($data);
 899                         }
 900
 901                         $id = JsonLD::fetchElement($object, '@id');
 902                         if (empty($id)) {
 903                                 Logger::info('Empty id');
 904                                 return false;
 905                         }
 906
 907                         if ($id != $object_id) {
 908                                 Logger::info('Fetched id differs from provided id', ['provided' => $object_id, 'fetched' => $id]);
 909                                 return false;
 910                         }
 911                 } else {
 912                         Logger::log('Using original object for url ' . $object_id, Logger::DEBUG);
 913                 }
 914
 915                 $type = JsonLD::fetchElement($object, '@type');
 916                 if (empty($type)) {
 917                         Logger::info('Empty type');
 918                         return false;
 919                 }
 920
 921                 // We currently don't handle 'pt:CacheFile', but with this step we avoid logging
 922                 if (in_array($type, self::CONTENT_TYPES) || ($type == 'pt:CacheFile')) {
 923                         $object_data = self::processObject($object);
 924
 925                         if (!empty($data)) {
 926                                 $object_data['raw'] = json_encode($data);
 927                         }
 928                         return $object_data;
 929                 }
 930
 931                 if ($type == 'as:Announce') {
 932                         $object_id = JsonLD::fetchElement($object, 'object', '@id');
 933                         if (empty($object_id) || !is_string($object_id)) {
 934                                 return false;
 935                         }
 936                         return self::fetchObject($object_id, [], false, $uid);
 937                 }
 938
 939                 Logger::log('Unhandled object type: ' . $type, Logger::DEBUG);
 940                 return false;
 941         }
 942
 943         /**
 944          * Convert tags from JSON-LD format into a simplified format
 945          *
 946          * @param array $tags Tags in JSON-LD format
 947          *
 948          * @return array with tags in a simplified format
 949          */
 950         private static function processTags(array $tags)
 951         {
 952                 $taglist = [];
 953
 954                 foreach ($tags as $tag) {
 955                         if (empty($tag)) {
 956                                 continue;
 957                         }
 958
 959                         $element = ['type' => str_replace('as:', '', JsonLD::fetchElement($tag, '@type')),
 960                                 'href' => JsonLD::fetchElement($tag, 'as:href', '@id'),
 961                                 'name' => JsonLD::fetchElement($tag, 'as:name', '@value')];
 962
 963                         if (empty($element['type'])) {
 964                                 continue;
 965                         }
 966
 967                         if (empty($element['href'])) {
 968                                 $element['href'] = $element['name'];
 969                         }
 970
 971                         $taglist[] = $element;
 972                 }
 973                 return $taglist;
 974         }
 975
 976         /**
 977          * Convert emojis from JSON-LD format into a simplified format
 978          *
 979          * @param array $emojis
 980          * @return array with emojis in a simplified format
 981          */
 982         private static function processEmojis(array $emojis)
 983         {
 984                 $emojilist = [];
 985
 986                 foreach ($emojis as $emoji) {
 987                         if (empty($emoji) || (JsonLD::fetchElement($emoji, '@type') != 'toot:Emoji') || empty($emoji['as:icon'])) {
 988                                 continue;
 989                         }
 990
 991                         $url = JsonLD::fetchElement($emoji['as:icon'], 'as:url', '@id');
 992                         $element = ['name' => JsonLD::fetchElement($emoji, 'as:name', '@value'),
 993                                 'href' => $url];
 994
 995                         $emojilist[] = $element;
 996                 }
 997
 998                 return $emojilist;
 999         }
1000
1001         /**
1002          * Convert attachments from JSON-LD format into a simplified format
1003          *
1004          * @param array $attachments Attachments in JSON-LD format
1005          *
1006          * @return array Attachments in a simplified format
1007          */
1008         private static function processAttachments(array $attachments)
1009         {
1010                 $attachlist = [];
1011
1012                 // Removes empty values
1013                 $attachments = array_filter($attachments);
1014
1015                 foreach ($attachments as $attachment) {
1016                         switch (JsonLD::fetchElement($attachment, '@type')) {
1017                                 case 'as:Page':
1018                                         $pageUrl = null;
1019                                         $pageImage = null;
1020
1021                                         $urls = JsonLD::fetchElementArray($attachment, 'as:url');
1022                                         foreach ($urls as $url) {
1023                                                 // Single scalar URL case
1024                                                 if (is_string($url)) {
1025                                                         $pageUrl = $url;
1026                                                         continue;
1027                                                 }
1028
1029                                                 $href = JsonLD::fetchElement($url, 'as:href', '@id');
1030                                                 $mediaType = JsonLD::fetchElement($url, 'as:mediaType', '@value');
1031                                                 if (Strings::startsWith($mediaType, 'image')) {
1032                                                         $pageImage = $href;
1033                                                 } else {
1034                                                         $pageUrl = $href;
1035                                                 }
1036                                         }
1037
1038                                         $attachlist[] = [
1039                                                 'type'  => 'link',
1040                                                 'title' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1041                                                 'desc'  => JsonLD::fetchElement($attachment, 'as:summary', '@value'),
1042                                                 'url'   => $pageUrl,
1043                                                 'image' => $pageImage,
1044                                         ];
1045                                         break;
1046                                 case 'as:Link':
1047                                         $attachlist[] = [
1048                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1049                                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType', '@value'),
1050                                                 'name' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1051                                                 'url' => JsonLD::fetchElement($attachment, 'as:href', '@id')
1052                                         ];
1053                                         break;
1054                                 case 'as:Image':
1055                                         $mediaType = JsonLD::fetchElement($attachment, 'as:mediaType', '@value');
1056                                         $imageFullUrl = JsonLD::fetchElement($attachment, 'as:url', '@id');
1057                                         $imagePreviewUrl = null;
1058                                         // Multiple URLs?
1059                                         if (!$imageFullUrl && ($urls = JsonLD::fetchElementArray($attachment, 'as:url'))) {
1060                                                 $imageVariants = [];
1061                                                 $previewVariants = [];
1062                                                 foreach ($urls as $url) {
1063                                                         // Scalar URL, no discrimination possible
1064                                                         if (is_string($url)) {
1065                                                                 $imageFullUrl = $url;
1066                                                                 continue;
1067                                                         }
1068
1069                                                         // Not sure what to do with a different Link media type than the base Image, we skip
1070                                                         if ($mediaType != JsonLD::fetchElement($url, 'as:mediaType', '@value')) {
1071                                                                 continue;
1072                                                         }
1073
1074                                                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1075
1076                                                         // Default URL choice if no discriminating width is provided
1077                                                         $imageFullUrl = $href ?? $imageFullUrl;
1078
1079                                                         $width = intval(JsonLD::fetchElement($url, 'as:width', '@value') ?? 1);
1080
1081                                                         if ($href && $width) {
1082                                                                 $imageVariants[$width] = $href;
1083                                                                 // 632 is the ideal width for full screen frio posts, we compute the absolute distance to it
1084                                                                 $previewVariants[abs(632 - $width)] = $href;
1085                                                         }
1086                                                 }
1087
1088                                                 if ($imageVariants) {
1089                                                         // Taking the maximum size image
1090                                                         ksort($imageVariants);
1091                                                         $imageFullUrl = array_pop($imageVariants);
1092
1093                                                         // Taking the minimum number distance to the target distance
1094                                                         ksort($previewVariants);
1095                                                         $imagePreviewUrl = array_shift($previewVariants);
1096                                                 }
1097
1098                                                 unset($imageVariants);
1099                                                 unset($previewVariants);
1100                                         }
1101
1102                                         $attachlist[] = [
1103                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1104                                                 'mediaType' => $mediaType,
1105                                                 'name'  => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1106                                                 'url'   => $imageFullUrl,
1107                                                 'image' => $imagePreviewUrl !== $imageFullUrl ? $imagePreviewUrl : null,
1108                                         ];
1109                                         break;
1110                                 default:
1111                                         $attachlist[] = [
1112                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1113                                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType', '@value'),
1114                                                 'name' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1115                                                 'url' => JsonLD::fetchElement($attachment, 'as:url', '@id')
1116                                         ];
1117                         }
1118                 }
1119
1120                 return $attachlist;
1121         }
1122
1123         /**
1124          * Fetch the original source or content with the "language" Markdown or HTML
1125          *
1126          * @param array $object
1127          * @param array $object_data
1128          *
1129          * @return array
1130          * @throws \Exception
1131          */
1132         private static function getSource($object, $object_data)
1133         {
1134                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/bbcode');
1135                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1136                 if (!empty($object_data['source'])) {
1137                         return $object_data;
1138                 }
1139
1140                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/markdown');
1141                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1142                 if (!empty($object_data['source'])) {
1143                         $object_data['source'] = Markdown::toBBCode($object_data['source']);
1144                         return $object_data;
1145                 }
1146
1147                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/html');
1148                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1149                 if (!empty($object_data['source'])) {
1150                         $object_data['source'] = HTML::toBBCode($object_data['source']);
1151                         return $object_data;
1152                 }
1153
1154                 return $object_data;
1155         }
1156
1157         /**
1158          * Check if the "as:url" element is an array with multiple links
1159          * This is the case with audio and video posts.
1160          * Then the links are added as attachments
1161          *
1162          * @param array $object      The raw object
1163          * @param array $object_data The parsed object data for later processing
1164          * @return array the object data
1165          */
1166         private static function processAttachmentUrls(array $object, array $object_data) {
1167                 // Check if this is some url with multiple links
1168                 if (empty($object['as:url'])) {
1169                         return $object_data;
1170                 }
1171
1172                 $urls = $object['as:url'];
1173                 $keys = array_keys($urls);
1174                 if (!is_numeric(array_pop($keys))) {
1175                         return $object_data;
1176                 }
1177
1178                 $attachments = [];
1179
1180                 foreach ($urls as $url) {
1181                         if (empty($url['@type']) || ($url['@type'] != 'as:Link')) {
1182                                 continue;
1183                         }
1184
1185                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1186                         if (empty($href)) {
1187                                 continue;
1188                         }
1189
1190                         $mediatype = JsonLD::fetchElement($url, 'as:mediaType');
1191                         if (empty($mediatype)) {
1192                                 continue;
1193                         }
1194
1195                         if ($mediatype == 'text/html') {
1196                                 $object_data['alternate-url'] = $href;
1197                         }
1198
1199                         $filetype = strtolower(substr($mediatype, 0, strpos($mediatype, '/')));
1200
1201                         if ($filetype == 'audio') {
1202                                 $attachments[$filetype] = ['type' => $mediatype, 'url' => $href];
1203                         } elseif ($filetype == 'video') {
1204                                 $height = (int)JsonLD::fetchElement($url, 'as:height', '@value');
1205
1206                                 // We save bandwidth by using a moderate height
1207                                 // Peertube normally uses these heights: 240, 360, 480, 720, 1080
1208                                 if (!empty($attachments[$filetype]['height']) &&
1209                                         (($height > 480) || $height < $attachments[$filetype]['height'])) {
1210                                         continue;
1211                                 }
1212
1213                                 $attachments[$filetype] = ['type' => $mediatype, 'url' => $href, 'height' => $height];
1214                         }
1215                 }
1216
1217                 foreach ($attachments as $type => $attachment) {
1218                         $object_data['attachments'][] = ['type' => $type,
1219                                 'mediaType' => $attachment['type'],
1220                                 'name' => '',
1221                                 'url' => $attachment['url']];
1222                 }
1223                 return $object_data;
1224         }
1225
1226         /**
1227          * Fetches data from the object part of an activity
1228          *
1229          * @param array $object
1230          *
1231          * @return array
1232          * @throws \Exception
1233          */
1234         private static function processObject($object)
1235         {
1236                 if (!JsonLD::fetchElement($object, '@id')) {
1237                         return false;
1238                 }
1239
1240                 $object_data = [];
1241                 $object_data['object_type'] = JsonLD::fetchElement($object, '@type');
1242                 $object_data['id'] = JsonLD::fetchElement($object, '@id');
1243                 $object_data['reply-to-id'] = JsonLD::fetchElement($object, 'as:inReplyTo', '@id');
1244
1245                 // An empty "id" field is translated to "./" by the compactor, so we have to check for this content
1246                 if (empty($object_data['reply-to-id']) || ($object_data['reply-to-id'] == './')) {
1247                         $object_data['reply-to-id'] = $object_data['id'];
1248                 } else {
1249                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
1250                         $replyToId = Item::getURIByLink($object_data['reply-to-id']);
1251                         if (!empty($replyToId) && ($object_data['reply-to-id'] != $replyToId)) {
1252                                 Logger::notice('Fix wrong reply-to', ['received' => $object_data['reply-to-id'], 'correct' => $replyToId]);
1253                                 $object_data['reply-to-id'] = $replyToId;
1254                         }
1255                 }
1256
1257                 $object_data['published'] = JsonLD::fetchElement($object, 'as:published', '@value');
1258                 $object_data['updated'] = JsonLD::fetchElement($object, 'as:updated', '@value');
1259
1260                 if (empty($object_data['updated'])) {
1261                         $object_data['updated'] = $object_data['published'];
1262                 }
1263
1264                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
1265                         $object_data['published'] = $object_data['updated'];
1266                 }
1267
1268                 $actor = JsonLD::fetchElement($object, 'as:attributedTo', '@id');
1269                 if (empty($actor)) {
1270                         $actor = JsonLD::fetchElement($object, 'as:actor', '@id');
1271                 }
1272
1273                 $location = JsonLD::fetchElement($object, 'as:location', 'as:name', '@type', 'as:Place');
1274                 $location = JsonLD::fetchElement($location, 'location', '@value');
1275                 if ($location) {
1276                         // Some AP software allow formatted text in post location, so we run all the text converters we have to boil
1277                         // down to HTML and then finally format to plaintext.
1278                         $location = Markdown::convert($location);
1279                         $location = BBCode::convert($location);
1280                         $location = HTML::toPlaintext($location);
1281                 }
1282
1283                 $object_data['sc:identifier'] = JsonLD::fetchElement($object, 'sc:identifier', '@value');
1284                 $object_data['diaspora:guid'] = JsonLD::fetchElement($object, 'diaspora:guid', '@value');
1285                 $object_data['diaspora:comment'] = JsonLD::fetchElement($object, 'diaspora:comment', '@value');
1286                 $object_data['diaspora:like'] = JsonLD::fetchElement($object, 'diaspora:like', '@value');
1287                 $object_data['actor'] = $object_data['author'] = $actor;
1288                 $object_data['context'] = JsonLD::fetchElement($object, 'as:context', '@id');
1289                 $object_data['conversation'] = JsonLD::fetchElement($object, 'ostatus:conversation', '@id');
1290                 $object_data['sensitive'] = JsonLD::fetchElement($object, 'as:sensitive');
1291                 $object_data['name'] = JsonLD::fetchElement($object, 'as:name', '@value');
1292                 $object_data['summary'] = JsonLD::fetchElement($object, 'as:summary', '@value');
1293                 $object_data['content'] = JsonLD::fetchElement($object, 'as:content', '@value');
1294                 $object_data = self::getSource($object, $object_data);
1295                 $object_data['start-time'] = JsonLD::fetchElement($object, 'as:startTime', '@value');
1296                 $object_data['end-time'] = JsonLD::fetchElement($object, 'as:endTime', '@value');
1297                 $object_data['location'] = $location;
1298                 $object_data['latitude'] = JsonLD::fetchElement($object, 'as:location', 'as:latitude', '@type', 'as:Place');
1299                 $object_data['latitude'] = JsonLD::fetchElement($object_data, 'latitude', '@value');
1300                 $object_data['longitude'] = JsonLD::fetchElement($object, 'as:location', 'as:longitude', '@type', 'as:Place');
1301                 $object_data['longitude'] = JsonLD::fetchElement($object_data, 'longitude', '@value');
1302                 $object_data['attachments'] = self::processAttachments(JsonLD::fetchElementArray($object, 'as:attachment') ?? []);
1303                 $object_data['tags'] = self::processTags(JsonLD::fetchElementArray($object, 'as:tag') ?? []);
1304                 $object_data['emojis'] = self::processEmojis(JsonLD::fetchElementArray($object, 'as:tag', 'toot:Emoji') ?? []);
1305                 $object_data['generator'] = JsonLD::fetchElement($object, 'as:generator', 'as:name', '@type', 'as:Application');
1306                 $object_data['generator'] = JsonLD::fetchElement($object_data, 'generator', '@value');
1307                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'as:url', '@id');
1308
1309                 // Special treatment for Hubzilla links
1310                 if (is_array($object_data['alternate-url'])) {
1311                         $object_data['alternate-url'] = JsonLD::fetchElement($object_data['alternate-url'], 'as:href', '@id');
1312
1313                         if (!is_string($object_data['alternate-url'])) {
1314                                 $object_data['alternate-url'] = JsonLD::fetchElement($object['as:url'], 'as:href', '@id');
1315                         }
1316                 }
1317
1318                 if (in_array($object_data['object_type'], ['as:Audio', 'as:Video'])) {
1319                         $object_data = self::processAttachmentUrls($object, $object_data);
1320                 }
1321
1322                 $receiverdata = self::getReceivers($object, $object_data['actor'], $object_data['tags'], true);
1323                 $receivers = $reception_types = [];
1324                 foreach ($receiverdata as $key => $data) {
1325                         $receivers[$key] = $data['uid'];
1326                         $reception_types[$data['uid']] = $data['type'] ?? 0;
1327                 }
1328
1329                 $object_data['receiver'] = $receivers;
1330                 $object_data['reception_type'] = $reception_types;
1331
1332                 $object_data['unlisted'] = in_array(-1, $object_data['receiver']);
1333                 unset($object_data['receiver']['uid:-1']);
1334
1335                 // Common object data:
1336
1337                 // Unhandled
1338                 // @context, type, actor, signature, mediaType, duration, replies, icon
1339
1340                 // Also missing: (Defined in the standard, but currently unused)
1341                 // audience, preview, endTime, startTime, image
1342
1343                 // Data in Notes:
1344
1345                 // Unhandled
1346                 // contentMap, announcement_count, announcements, context_id, likes, like_count
1347                 // inReplyToStatusId, shares, quoteUrl, statusnetConversationId
1348
1349                 // Data in video:
1350
1351                 // To-Do?
1352                 // category, licence, language, commentsEnabled
1353
1354                 // Unhandled
1355                 // views, waitTranscoding, state, support, subtitleLanguage
1356                 // likes, dislikes, shares, comments
1357
1358                 return $object_data;
1359         }
1360 }