src/Protocol/ActivityPub/Receiver.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2010-2022, 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\Core\System;
  31 use Friendica\DI;
  32 use Friendica\Model\Contact;
  33 use Friendica\Model\APContact;
  34 use Friendica\Model\Item;
  35 use Friendica\Model\Post;
  36 use Friendica\Model\User;
  37 use Friendica\Protocol\Activity;
  38 use Friendica\Protocol\ActivityPub;
  39 use Friendica\Util\HTTPSignature;
  40 use Friendica\Util\JsonLD;
  41 use Friendica\Util\LDSignature;
  42 use Friendica\Util\Network;
  43 use Friendica\Util\Strings;
  44
  45 /**
  46  * ActivityPub Receiver Protocol class
  47  *
  48  * To-Do:
  49  * @todo Undo Announce
  50  *
  51  * Check what this is meant to do:
  52  * - Add
  53  * - Block
  54  * - Flag
  55  * - Remove
  56  * - Undo Block
  57  */
  58 class Receiver
  59 {
  60         const PUBLIC_COLLECTION = 'as:Public';
  61         const ACCOUNT_TYPES = ['as:Person', 'as:Organization', 'as:Service', 'as:Group', 'as:Application'];
  62         const CONTENT_TYPES = ['as:Note', 'as:Article', 'as:Video', 'as:Image', 'as:Event', 'as:Audio', 'as:Page', 'as:Question'];
  63         const ACTIVITY_TYPES = ['as:Like', 'as:Dislike', 'as:Accept', 'as:Reject', 'as:TentativeAccept'];
  64
  65         const TARGET_UNKNOWN = 0;
  66         const TARGET_TO = 1;
  67         const TARGET_CC = 2;
  68         const TARGET_BTO = 3;
  69         const TARGET_BCC = 4;
  70         const TARGET_FOLLOWER = 5;
  71         const TARGET_ANSWER = 6;
  72         const TARGET_GLOBAL = 7;
  73
  74         const COMPLETION_NONE    = 0;
  75         const COMPLETION_ANNOUCE = 1;
  76         const COMPLETION_RELAY   = 2;
  77         const COMPLETION_MANUAL  = 3;
  78         const COMPLETION_AUTO    = 4;
  79
  80         /**
  81          * Checks incoming message from the inbox
  82          *
  83          * @param string  $body Body string
  84          * @param array   $header Header lines
  85          * @param integer $uid User ID
  86          * @return void
  87          * @throws \Exception
  88          */
  89         public static function processInbox(string $body, array $header, int $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
 103                 if (empty($apcontact)) {
 104                         Logger::notice('Unable to retrieve AP contact for actor - message is discarded', ['actor' => $actor]);
 105                         return;
 106                 } elseif (APContact::isRelay($apcontact)) {
 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::info('Invalid JSON-LD signature from ' . $actor);
 132                         } elseif ($ld_signer != $http_signer) {
 133                                 $signer[] = $ld_signer;
 134                         }
 135                         if (!empty($ld_signer && ($actor == $http_signer))) {
 136                                 Logger::info('The HTTP and the JSON-LD signature belong to ' . $ld_signer);
 137                                 $trust_source = true;
 138                         } elseif (!empty($ld_signer)) {
 139                                 Logger::info('JSON-LD signature is signed by ' . $ld_signer);
 140                                 $trust_source = true;
 141                         } elseif ($actor == $http_signer) {
 142                                 Logger::info('Bad JSON-LD signature, but HTTP signer fits the actor.');
 143                                 $trust_source = true;
 144                         } else {
 145                                 Logger::info('Invalid JSON-LD signature and the HTTP signer is different.');
 146                                 $trust_source = false;
 147                         }
 148                 } elseif ($actor == $http_signer) {
 149                         Logger::info('Trusting post without JSON-LD signature, The actor fits the HTTP signer.');
 150                         $trust_source = true;
 151                 } else {
 152                         Logger::info('No JSON-LD signature, different actor.');
 153                         $trust_source = false;
 154                 }
 155
 156                 self::processActivity($ldactivity, $body, $uid, $trust_source, true, $signer, $http_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, 'actor' => $actor]);
 171                         return;
 172                 }
 173
 174                 if ($type != 'as:Announce') {
 175                         Logger::info('Not an announcement', ['activity' => $activity, 'actor' => $actor]);
 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, 'actor' => $actor]);
 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, 'actor' => $actor]);
 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, 'actor' => $actor]);
 201                         return;
 202                 }
 203
 204                 $id = Processor::fetchMissingActivity($object_id, [], $actor, self::COMPLETION_RELAY);
 205                 if (empty($id)) {
 206                         Logger::notice('Relayed message had not been fetched', ['id' => $object_id, 'actor' => $actor]);
 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, 'actor' => $actor]);
 213                 } else {
 214                         Logger::notice('Relayed message had not been stored', ['id' => $object_id, 'actor' => $actor]);
 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 or NULL
 226          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 227          * @throws \ImagickException
 228          */
 229         private static function fetchObjectType(array $activity, string $object_id, int $uid = 0)
 230         {
 231                 if (!empty($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(array $activity, int $uid, bool $push, bool &$trust_source): array
 274         {
 275                 $id = JsonLD::fetchElement($activity, '@id');
 276                 if (!empty($id) && !$trust_source) {
 277                         $fetch_uid = $uid ?: self::getBestUserForActivity($activity);
 278
 279                         $fetched_activity = ActivityPub::fetchContent($id, $fetch_uid);
 280                         if (!empty($fetched_activity)) {
 281                                 $object = JsonLD::compact($fetched_activity);
 282                                 $fetched_id = JsonLD::fetchElement($object, '@id');
 283                                 if ($fetched_id == $id) {
 284                                         Logger::info('Activity had been fetched successfully', ['id' => $id]);
 285                                         $trust_source = true;
 286                                         $activity = $object;
 287                                 } else {
 288                                         Logger::info('Activity id is not equal', ['id' => $id, 'fetched' => $fetched_id]);
 289                                 }
 290                         } else {
 291                                 Logger::info('Activity could not been fetched', ['id' => $id]);
 292                         }
 293                 }
 294
 295                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 296                 if (empty($actor)) {
 297                         Logger::info('Empty actor', ['activity' => $activity]);
 298                         return [];
 299                 }
 300
 301                 $type = JsonLD::fetchElement($activity, '@type');
 302
 303                 // Fetch all receivers from to, cc, bto and bcc
 304                 $receiverdata = self::getReceivers($activity, $actor);
 305                 $receivers = $reception_types = [];
 306                 foreach ($receiverdata as $key => $data) {
 307                         $receivers[$key] = $data['uid'];
 308                         $reception_types[$data['uid']] = $data['type'] ?? self::TARGET_UNKNOWN;
 309                 }
 310
 311                 $urls = self::getReceiverURL($activity);
 312
 313                 // When it is a delivery to a personal inbox we add that user to the receivers
 314                 if (!empty($uid)) {
 315                         $additional = [$uid => $uid];
 316                         $receivers = array_replace($receivers, $additional);
 317                         if (empty($activity['thread-completion']) && (empty($reception_types[$uid]) || in_array($reception_types[$uid], [self::TARGET_UNKNOWN, self::TARGET_FOLLOWER, self::TARGET_ANSWER, self::TARGET_GLOBAL]))) {
 318                                 $reception_types[$uid] = self::TARGET_BCC;
 319                                 $owner = User::getOwnerDataById($uid);
 320                                 if (!empty($owner['url'])) {
 321                                         $urls['as:bcc'][] = $owner['url'];
 322                                 }
 323                         }
 324                 }
 325
 326                 // We possibly need some user to fetch private content,
 327                 // so we fetch one out of the receivers if no uid is provided.
 328                 $fetch_uid = $uid ?: self::getBestUserForActivity($activity);
 329
 330                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 331                 if (empty($object_id)) {
 332                         Logger::info('No object found');
 333                         return [];
 334                 }
 335
 336                 if (!is_string($object_id)) {
 337                         Logger::info('Invalid object id', ['object' => $object_id]);
 338                         return [];
 339                 }
 340
 341                 $object_type = self::fetchObjectType($activity, $object_id, $fetch_uid);
 342
 343                 // Fetch the activity on Lemmy "Announce" messages (announces of activities)
 344                 if (($type == 'as:Announce') && in_array($object_type, array_merge(self::ACTIVITY_TYPES, ['as:Delete', 'as:Undo', 'as:Update']))) {
 345                         $data = ActivityPub::fetchContent($object_id, $fetch_uid);
 346                         if (!empty($data)) {
 347                                 $type = $object_type;
 348                                 $activity = JsonLD::compact($data);
 349
 350                                 // Some variables need to be refetched since the activity changed
 351                                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 352                                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 353                                 $object_type = self::fetchObjectType($activity, $object_id, $fetch_uid);
 354                         }
 355                 }
 356
 357                 // Any activities on account types must not be altered
 358                 if (in_array($object_type, self::ACCOUNT_TYPES)) {
 359                         $object_data = [];
 360                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 361                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 362                         $object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor', '@id');
 363                         $object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
 364                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 365                         $object_data['push'] = $push;
 366                 } elseif (in_array($type, ['as:Create', 'as:Update', 'as:Announce', 'as:Invite']) || strpos($type, '#emojiReaction')) {
 367                         // Fetch the content only on activities where this matters
 368                         // We can receive "#emojiReaction" when fetching content from Hubzilla systems
 369                         // Always fetch on "Announce"
 370                         $object_data = self::fetchObject($object_id, $activity['as:object'], $trust_source && ($type != 'as:Announce'), $fetch_uid);
 371                         if (empty($object_data)) {
 372                                 Logger::info("Object data couldn't be processed");
 373                                 return [];
 374                         }
 375
 376                         $object_data['object_id'] = $object_id;
 377
 378                         if ($type == 'as:Announce') {
 379                                 $object_data['push'] = false;
 380                         } else {
 381                                 $object_data['push'] = $push;
 382                         }
 383
 384                         // Test if it is an answer to a mail
 385                         if (DBA::exists('mail', ['uri' => $object_data['reply-to-id']])) {
 386                                 $object_data['directmessage'] = true;
 387                         } else {
 388                                 $object_data['directmessage'] = JsonLD::fetchElement($activity, 'litepub:directMessage');
 389                         }
 390                 } elseif (in_array($type, array_merge(self::ACTIVITY_TYPES, ['as:Follow', 'litepub:EmojiReact', 'as:View'])) && in_array($object_type, self::CONTENT_TYPES)) {
 391                         // Create a mostly empty array out of the activity data (instead of the object).
 392                         // This way we later don't have to check for the existence of each individual array element.
 393                         $object_data = self::processObject($activity);
 394                         $object_data['name'] = $type;
 395                         $object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 396                         $object_data['object_id'] = $object_id;
 397                         $object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
 398                         $object_data['push'] = $push;
 399                 } elseif (in_array($type, ['as:Add', 'as:Remove'])) {
 400                         $object_data = [];
 401                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 402                         $object_data['target_id'] = JsonLD::fetchElement($activity, 'as:target', '@id');
 403                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 404                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 405                         $object_data['object_content'] = JsonLD::fetchElement($activity['as:object'], 'as:content', '@type');
 406                         $object_data['push'] = $push;
 407                 } else {
 408                         $object_data = [];
 409                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 410                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 411                         $object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor', '@id');
 412                         $object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
 413                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 414                         $object_data['push'] = $push;
 415
 416                         // An Undo is done on the object of an object, so we need that type as well
 417                         if (($type == 'as:Undo') && !empty($object_data['object_object'])) {
 418                                 $object_data['object_object_type'] = self::fetchObjectType([], $object_data['object_object'], $fetch_uid);
 419                         }
 420                 }
 421
 422                 $object_data = self::addActivityFields($object_data, $activity);
 423
 424                 if (empty($object_data['object_type'])) {
 425                         $object_data['object_type'] = $object_type;
 426                 }
 427
 428                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
 429                         if ((empty($object_data['receiver_urls'][$element]) || in_array($element, ['as:bto', 'as:bcc'])) && !empty($urls[$element])) {
 430                                 $object_data['receiver_urls'][$element] = array_unique(array_merge($object_data['receiver_urls'][$element] ?? [], $urls[$element]));
 431                         }
 432                 }
 433
 434                 $object_data['type'] = $type;
 435                 $object_data['actor'] = $actor;
 436                 $object_data['item_receiver'] = $receivers;
 437                 $object_data['receiver'] = array_replace($object_data['receiver'] ?? [], $receivers);
 438                 $object_data['reception_type'] = array_replace($object_data['reception_type'] ?? [], $reception_types);
 439
 440 //              This check here interferes with Hubzilla posts where the author host differs from the host the post was created
 441 //              $author = $object_data['author'] ?? $actor;
 442 //              if (!empty($author) && !empty($object_data['id'])) {
 443 //                      $author_host = parse_url($author, PHP_URL_HOST);
 444 //                      $id_host = parse_url($object_data['id'], PHP_URL_HOST);
 445 //                      if ($author_host == $id_host) {
 446 //                              Logger::info('Valid hosts', ['type' => $type, 'host' => $id_host]);
 447 //                      } else {
 448 //                              Logger::notice('Differing hosts on author and id', ['type' => $type, 'author' => $author_host, 'id' => $id_host]);
 449 //                              $trust_source = false;
 450 //                      }
 451 //              }
 452
 453                 Logger::info('Processing ' . $object_data['type'] . ' ' . $object_data['object_type'] . ' ' . $object_data['id']);
 454
 455                 return $object_data;
 456         }
 457
 458         /**
 459          * Fetches the first user id from the receiver array
 460          *
 461          * @param array $receivers Array with receivers
 462          * @return integer user id;
 463          */
 464         public static function getFirstUserFromReceivers(array $receivers): int
 465         {
 466                 foreach ($receivers as $receiver) {
 467                         if (!empty($receiver)) {
 468                                 return $receiver;
 469                         }
 470                 }
 471                 return 0;
 472         }
 473
 474         /**
 475          * Processes the activity object
 476          *
 477          * @param array      $activity     Array with activity data
 478          * @param string     $body         The unprocessed body
 479          * @param int|null   $uid          User ID
 480          * @param boolean    $trust_source Do we trust the source?
 481          * @param boolean    $push         Message had been pushed to our system
 482          * @param array      $signer       The signer of the post
 483          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 484          * @throws \ImagickException
 485          */
 486         public static function processActivity(array $activity, string $body = '', int $uid = null, bool $trust_source = false, bool $push = false, array $signer = [], string $http_signer = '')
 487         {
 488                 $type = JsonLD::fetchElement($activity, '@type');
 489                 if (!$type) {
 490                         Logger::info('Empty type', ['activity' => $activity]);
 491                         return;
 492                 }
 493
 494                 if (!JsonLD::fetchElement($activity, 'as:object', '@id')) {
 495                         Logger::info('Empty object', ['activity' => $activity]);
 496                         return;
 497                 }
 498
 499                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 500                 if (empty($actor)) {
 501                         Logger::info('Empty actor', ['activity' => $activity]);
 502                         return;
 503                 }
 504
 505                 if (is_array($activity['as:object'])) {
 506                         $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
 507                 } else {
 508                         $attributed_to = '';
 509                 }
 510
 511                 // Test the provided signatures against the actor and "attributedTo"
 512                 if ($trust_source) {
 513                         if (!empty($attributed_to) && !empty($actor)) {
 514                                 $trust_source = (in_array($actor, $signer) && in_array($attributed_to, $signer));
 515                         } else {
 516                                 $trust_source = in_array($actor, $signer);
 517                         }
 518                 }
 519
 520                 // $trust_source is called by reference and is set to true if the content was retrieved successfully
 521                 $object_data = self::prepareObjectData($activity, $uid, $push, $trust_source);
 522                 if (empty($object_data)) {
 523                         Logger::info('No object data found', ['activity' => $activity]);
 524                         return;
 525                 }
 526
 527                 // Lemmy is announcing activities.
 528                 // We are changing the announces into regular activities.
 529                 if (($type == 'as:Announce') && in_array($object_data['type'] ?? '', array_merge(self::ACTIVITY_TYPES, ['as:Delete', 'as:Undo', 'as:Update']))) {
 530                         $type = $object_data['type'];
 531                 }
 532
 533                 if (!empty($body) && empty($object_data['raw'])) {
 534                         $object_data['raw'] = $body;
 535                 }
 536
 537                 // Internal flag for thread completion. See Processor.php
 538                 if (!empty($activity['thread-completion'])) {
 539                         $object_data['thread-completion'] = $activity['thread-completion'];
 540                 }
 541
 542                 if (!empty($activity['completion-mode'])) {
 543                         $object_data['completion-mode'] = $activity['completion-mode'];
 544                 }
 545
 546                 if (!empty($activity['thread-children-type'])) {
 547                         $object_data['thread-children-type'] = $activity['thread-children-type'];
 548                 }
 549
 550                 // Internal flag for posts that arrived via relay
 551                 if (!empty($activity['from-relay'])) {
 552                         $object_data['from-relay'] = $activity['from-relay'];
 553                 }
 554
 555                 if ($type == 'as:Announce') {
 556                         $object_data['object_activity'] = $activity;
 557                 }
 558
 559                 $object_data = Queue::add($object_data, $type, $uid, $http_signer, $push, $trust_source);
 560
 561                 if (!$trust_source) {
 562                         Logger::info('Activity trust could not be achieved.',  ['id' => $object_data['object_id'], 'type' => $type, 'signer' => $signer, 'actor' => $actor, 'attributedTo' => $attributed_to]);
 563                         return;
 564                 }
 565
 566                 if (!empty($activity['recursion-depth'])) {
 567                         $object_data['recursion-depth'] = $activity['recursion-depth'];
 568                 }
 569
 570                 if (in_array('as:Question', [$object_data['object_type'] ?? '', $object_data['object_object_type'] ?? ''])) {
 571                         self::storeUnhandledActivity(false, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 572                 }
 573
 574                 if (!self::routeActivities($object_data, $type, $push)) {
 575                         self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 576                         Queue::remove($object_data);
 577                 }
 578         }
 579
 580         /**
 581          * Route activities
 582          *
 583          * @param array   $object_data
 584          * @param string  $type
 585          * @param boolean $push
 586          *
 587          * @return boolean Could the activity be routed?
 588          */
 589         public static function routeActivities(array $object_data, string $type, bool $push): bool
 590         {
 591                 $activity = $object_data['object_activity']     ?? [];
 592
 593                 switch ($type) {
 594                         case 'as:Create':
 595                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 596                                         $item = ActivityPub\Processor::createItem($object_data);
 597                                         ActivityPub\Processor::postItem($object_data, $item);
 598                                 } elseif (in_array($object_data['object_type'], ['pt:CacheFile'])) {
 599                                         // Unhandled Peertube activity
 600                                         Queue::remove($object_data);
 601                                 } else {
 602                                         return false;
 603                                 }
 604                                 break;
 605
 606                         case 'as:Invite':
 607                                 if (in_array($object_data['object_type'], ['as:Event'])) {
 608                                         $item = ActivityPub\Processor::createItem($object_data);
 609                                         ActivityPub\Processor::postItem($object_data, $item);
 610                                 } else {
 611                                         return false;
 612                                 }
 613                                 break;
 614
 615                         case 'as:Add':
 616                                 if ($object_data['object_type'] == 'as:tag') {
 617                                         ActivityPub\Processor::addTag($object_data);
 618                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 619                                         ActivityPub\Processor::addToFeaturedCollection($object_data);
 620                                 } elseif ($object_data['object_type'] == '') {
 621                                         // The object type couldn't be determined. We don't have it and we can't fetch it. We ignore this activity.
 622                                         Queue::remove($object_data);
 623                                 } else {
 624                                         return false;
 625                                 }
 626                                 break;
 627
 628                         case 'as:Announce':
 629                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 630                                         $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 631                                         $object_data['thread-completion'] = Contact::getIdForURL($actor);
 632                                         $object_data['completion-mode']   = self::COMPLETION_ANNOUCE;
 633
 634                                         $item = ActivityPub\Processor::createItem($object_data);
 635                                         if (empty($item)) {
 636                                                 return false;
 637                                         }
 638
 639                                         $item['post-reason'] = Item::PR_ANNOUNCEMENT;
 640                                         ActivityPub\Processor::postItem($object_data, $item);
 641
 642                                         if (!empty($activity)) {
 643                                                 $announce_object_data = self::processObject($activity);
 644                                                 $announce_object_data['name'] = $type;
 645                                                 $announce_object_data['author'] = $actor;
 646                                                 $announce_object_data['object_id'] = $object_data['object_id'];
 647                                                 $announce_object_data['object_type'] = $object_data['object_type'];
 648                                                 $announce_object_data['push'] = $push;
 649
 650                                                 if (!empty($object_data['raw'])) {
 651                                                         $announce_object_data['raw'] = $object_data['raw'];
 652                                                 }
 653                                                 ActivityPub\Processor::createActivity($announce_object_data, Activity::ANNOUNCE);
 654                                         }
 655                                 } else {
 656                                         return false;
 657                                 }
 658                                 break;
 659
 660                         case 'as:Like':
 661                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 662                                         ActivityPub\Processor::createActivity($object_data, Activity::LIKE);
 663                                 } elseif ($object_data['object_type'] == '') {
 664                                         // The object type couldn't be determined. We don't have it and we can't fetch it. We ignore this activity.
 665                                         Queue::remove($object_data);
 666                                 } else {
 667                                         return false;
 668                                 }
 669                                 break;
 670
 671                         case 'as:Dislike':
 672                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 673                                         ActivityPub\Processor::createActivity($object_data, Activity::DISLIKE);
 674                                 } elseif ($object_data['object_type'] == '') {
 675                                         // The object type couldn't be determined. We don't have it and we can't fetch it. We ignore this activity.
 676                                         Queue::remove($object_data);
 677                                 } else {
 678                                         return false;
 679                                 }
 680                                 break;
 681
 682                         case 'as:TentativeAccept':
 683                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 684                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDMAYBE);
 685                                 } else {
 686                                         return false;
 687                                 }
 688                                 break;
 689
 690                         case 'as:Update':
 691                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 692                                         ActivityPub\Processor::updateItem($object_data);
 693                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 694                                         ActivityPub\Processor::updatePerson($object_data);
 695                                 } elseif (in_array($object_data['object_type'], ['pt:CacheFile'])) {
 696                                         // Unhandled Peertube activity
 697                                         Queue::remove($object_data);
 698                                 } else {
 699                                         return false;
 700                                 }
 701                                 break;
 702
 703                         case 'as:Delete':
 704                                 if (in_array($object_data['object_type'], array_merge(['as:Tombstone'], self::CONTENT_TYPES))) {
 705                                         ActivityPub\Processor::deleteItem($object_data);
 706                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 707                                         ActivityPub\Processor::deletePerson($object_data);
 708                                 } elseif ($object_data['object_type'] == '') {
 709                                         // The object type couldn't be determined. Most likely we don't have it here. We ignore this activity.
 710                                         Queue::remove($object_data);
 711                                 } else {
 712                                         return false;
 713                                 }
 714                                 break;
 715
 716                         case 'as:Block':
 717                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 718                                         ActivityPub\Processor::blockAccount($object_data);
 719                                 } else {
 720                                         return false;
 721                                 }
 722                                 break;
 723
 724                         case 'as:Remove':
 725                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 726                                         ActivityPub\Processor::removeFromFeaturedCollection($object_data);
 727                                 } elseif ($object_data['object_type'] == '') {
 728                                         // The object type couldn't be determined. We don't have it and we can't fetch it. We ignore this activity.
 729                                         Queue::remove($object_data);
 730                                 } else {
 731                                         return false;
 732                                 }
 733                                 break;
 734
 735                         case 'as:Follow':
 736                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 737                                         ActivityPub\Processor::followUser($object_data);
 738                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 739                                         $object_data['reply-to-id'] = $object_data['object_id'];
 740                                         ActivityPub\Processor::createActivity($object_data, Activity::FOLLOW);
 741                                 } else {
 742                                         return false;
 743                                 }
 744                                 break;
 745
 746                         case 'as:Accept':
 747                                 if ($object_data['object_type'] == 'as:Follow') {
 748                                         ActivityPub\Processor::acceptFollowUser($object_data);
 749                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 750                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTEND);
 751                                 } else {
 752                                         return false;
 753                                 }
 754                                 break;
 755
 756                         case 'as:Reject':
 757                                 if ($object_data['object_type'] == 'as:Follow') {
 758                                         ActivityPub\Processor::rejectFollowUser($object_data);
 759                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 760                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDNO);
 761                                 } else {
 762                                         return false;
 763                                 }
 764                                 break;
 765
 766                         case 'as:Undo':
 767                                 if (($object_data['object_type'] == 'as:Follow') &&
 768                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 769                                         ActivityPub\Processor::undoFollowUser($object_data);
 770                                 } elseif (($object_data['object_type'] == 'as:Follow') &&
 771                                         in_array($object_data['object_object_type'], self::CONTENT_TYPES)) {
 772                                         ActivityPub\Processor::undoActivity($object_data);
 773                                 } elseif (($object_data['object_type'] == 'as:Accept') &&
 774                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 775                                         ActivityPub\Processor::rejectFollowUser($object_data);
 776                                 } elseif (($object_data['object_type'] == 'as:Block') &&
 777                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 778                                         ActivityPub\Processor::unblockAccount($object_data);
 779                                 } elseif (in_array($object_data['object_type'], array_merge(self::ACTIVITY_TYPES, ['as:Announce'])) &&
 780                                         in_array($object_data['object_object_type'], array_merge(['as:Tombstone'], self::CONTENT_TYPES))) {
 781                                         ActivityPub\Processor::undoActivity($object_data);
 782                                 } elseif (in_array($object_data['object_type'], array_merge(self::ACTIVITY_TYPES, ['as:Announce', 'as:Create', ''])) &&
 783                                         empty($object_data['object_object_type'])) {
 784                                         // We cannot detect the target object. So we can ignore it.
 785                                         Queue::remove($object_data);
 786                                 } elseif (in_array($object_data['object_type'], ['as:Create']) &&
 787                                         in_array($object_data['object_object_type'], ['pt:CacheFile'])) {
 788                                         // Unhandled Peertube activity
 789                                         Queue::remove($object_data);
 790                                 } else {
 791                                         return false;
 792                                 }
 793                                 break;
 794
 795                         case 'as:View':
 796                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 797                                         ActivityPub\Processor::createActivity($object_data, Activity::VIEW);
 798                                 } elseif ($object_data['object_type'] == '') {
 799                                         // The object type couldn't be determined. Most likely we don't have it here. We ignore this activity.
 800                                         Queue::remove($object_data);
 801                                 } else {
 802                                         return false;
 803                                 }
 804                                 break;
 805
 806                         case 'litepub:EmojiReact':
 807                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 808                                         ActivityPub\Processor::createActivity($object_data, Activity::EMOJIREACT);
 809                                 } elseif ($object_data['object_type'] == '') {
 810                                         // The object type couldn't be determined. We don't have it and we can't fetch it. We ignore this activity.
 811                                         Queue::remove($object_data);
 812                                 } else {
 813                                         return false;
 814                                 }
 815                                 break;
 816
 817                         default:
 818                                 Logger::info('Unknown activity: ' . $type . ' ' . $object_data['object_type']);
 819                                 return false;
 820                 }
 821                 return true;
 822         }
 823
 824         /**
 825          * Stores unhandled or unknown Activities as a file
 826          *
 827          * @param boolean $unknown      "true" if the activity is unknown, "false" if it is unhandled
 828          * @param string  $type         Activity type
 829          * @param array   $object_data  Preprocessed array that is generated out of the received activity
 830          * @param array   $activity     Array with activity data
 831          * @param string  $body         The unprocessed body
 832          * @param integer $uid          User ID
 833          * @param boolean $trust_source Do we trust the source?
 834          * @param boolean $push         Message had been pushed to our system
 835          * @param array   $signer       The signer of the post
 836          * @return void
 837          */
 838         private static function storeUnhandledActivity(bool $unknown, string $type, array $object_data, array $activity, string $body = '', int $uid = null, bool $trust_source = false, bool $push = false, array $signer = [])
 839         {
 840                 if (!DI::config()->get('debug', 'ap_log_unknown')) {
 841                         return;
 842                 }
 843
 844                 $file = ($unknown  ? 'unknown-' : 'unhandled-') . str_replace(':', '-', $type) . '-';
 845
 846                 if (!empty($object_data['object_type'])) {
 847                         $file .= str_replace(':', '-', $object_data['object_type']) . '-';
 848                 }
 849
 850                 if (!empty($object_data['object_object_type'])) {
 851                         $file .= str_replace(':', '-', $object_data['object_object_type']) . '-';
 852                 }
 853
 854                 $tempfile = tempnam(System::getTempPath(), $file);
 855                 file_put_contents($tempfile, json_encode(['activity' => $activity, 'body' => $body, 'uid' => $uid, 'trust_source' => $trust_source, 'push' => $push, 'signer' => $signer, 'object_data' => $object_data], JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE | JSON_PRETTY_PRINT));
 856                 Logger::notice('Unknown activity stored', ['type' => $type, 'object_type' => $object_data['object_type'], $object_data['object_object_type'] ?? '', 'file' => $tempfile]);
 857         }
 858
 859         /**
 860          * Fetch a user id from an activity array
 861          *
 862          * @param array  $activity
 863          * @param string $actor
 864          *
 865          * @return int   user id
 866          */
 867         public static function getBestUserForActivity(array $activity): int
 868         {
 869                 $uid = 0;
 870                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id') ?? '';
 871
 872                 $receivers = self::getReceivers($activity, $actor);
 873                 foreach ($receivers as $receiver) {
 874                         if ($receiver['type'] == self::TARGET_GLOBAL) {
 875                                 return 0;
 876                         }
 877                         if (empty($uid) || ($receiver['type'] == self::TARGET_TO)) {
 878                                 $uid = $receiver['uid'];
 879                         }
 880                 }
 881
 882                 // When we haven't found any user yet, we just chose a user who most likely could have access to the content
 883                 if (empty($uid)) {
 884                         $contact = Contact::selectFirst(['uid'], ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND]]);
 885                         if (!empty($contact['uid'])) {
 886                                 $uid = $contact['uid'];
 887                         }
 888                 }
 889
 890                 return $uid;
 891         }
 892
 893         // @TODO Missing documentation
 894         public static function getReceiverURL(array $activity): array
 895         {
 896                 $urls = [];
 897
 898                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
 899                         $receiver_list = JsonLD::fetchElementArray($activity, $element, '@id');
 900                         if (empty($receiver_list)) {
 901                                 continue;
 902                         }
 903
 904                         foreach ($receiver_list as $receiver) {
 905                                 if ($receiver == self::PUBLIC_COLLECTION) {
 906                                         $receiver = ActivityPub::PUBLIC_COLLECTION;
 907                                 }
 908                                 $urls[$element][] = $receiver;
 909                         }
 910                 }
 911
 912                 return $urls;
 913         }
 914
 915         /**
 916          * Fetch the receiver list from an activity array
 917          *
 918          * @param array   $activity
 919          * @param string  $actor
 920          * @param array   $tags
 921          * @param boolean $fetch_unlisted
 922          *
 923          * @return array with receivers (user id)
 924          * @throws \Exception
 925          */
 926         private static function getReceivers(array $activity, string $actor, array $tags = [], bool $fetch_unlisted = false): array
 927         {
 928                 $reply = $receivers = $profile = [];
 929
 930                 // When it is an answer, we inherite the receivers from the parent
 931                 $replyto = JsonLD::fetchElement($activity, 'as:inReplyTo', '@id');
 932                 if (!empty($replyto)) {
 933                         $reply = [$replyto];
 934
 935                         // Fix possibly wrong item URI (could be an answer to a plink uri)
 936                         $fixedReplyTo = Item::getURIByLink($replyto);
 937                         if (!empty($fixedReplyTo)) {
 938                                 $reply[] = $fixedReplyTo;
 939                         }
 940                 }
 941
 942                 // Fetch all posts that refer to the object id
 943                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 944                 if (!empty($object_id)) {
 945                         $reply[] = $object_id;
 946                 }
 947
 948                 if (!empty($reply)) {
 949                         $parents = Post::select(['uid'], ['uri' => $reply]);
 950                         while ($parent = Post::fetch($parents)) {
 951                                 $receivers[$parent['uid']] = ['uid' => $parent['uid'], 'type' => self::TARGET_ANSWER];
 952                         }
 953                         DBA::close($parents);
 954                 }
 955
 956                 if (!empty($actor)) {
 957                         $profile   = APContact::getByURL($actor);
 958                         $followers = $profile['followers'] ?? '';
 959                         $is_forum  = ($actor['type'] ?? '') == 'Group';
 960                         Logger::info('Got actor and followers', ['actor' => $actor, 'followers' => $followers]);
 961                 } else {
 962                         Logger::info('Empty actor', ['activity' => $activity]);
 963                         $followers = '';
 964                         $is_forum  = false;
 965                 }
 966
 967                 // We have to prevent false follower assumptions upon thread completions
 968                 $follower_target = empty($activity['thread-completion']) ? self::TARGET_FOLLOWER : self::TARGET_UNKNOWN;
 969
 970                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
 971                         $receiver_list = JsonLD::fetchElementArray($activity, $element, '@id');
 972                         if (empty($receiver_list)) {
 973                                 continue;
 974                         }
 975
 976                         foreach ($receiver_list as $receiver) {
 977                                 if ($receiver == self::PUBLIC_COLLECTION) {
 978                                         $receivers[0] = ['uid' => 0, 'type' => self::TARGET_GLOBAL];
 979                                 }
 980
 981                                 // Add receiver "-1" for unlisted posts
 982                                 if ($fetch_unlisted && ($receiver == self::PUBLIC_COLLECTION) && ($element == 'as:cc')) {
 983                                         $receivers[-1] = ['uid' => -1, 'type' => self::TARGET_GLOBAL];
 984                                 }
 985
 986                                 // Fetch the receivers for the public and the followers collection
 987                                 if ((($receiver == $followers) || (($receiver == self::PUBLIC_COLLECTION) && !$is_forum)) && !empty($actor)) {
 988                                         $receivers = self::getReceiverForActor($actor, $tags, $receivers, $follower_target, $profile);
 989                                         continue;
 990                                 }
 991
 992                                 // Fetching all directly addressed receivers
 993                                 $condition = ['self' => true, 'nurl' => Strings::normaliseLink($receiver)];
 994                                 $contact = DBA::selectFirst('contact', ['uid', 'contact-type'], $condition);
 995                                 if (!DBA::isResult($contact)) {
 996                                         continue;
 997                                 }
 998
 999                                 // Check if the potential receiver is following the actor
1000                                 // Exception: The receiver is targetted via "to" or this is a comment
1001                                 if ((($element != 'as:to') && empty($replyto)) || ($contact['contact-type'] == Contact::TYPE_COMMUNITY)) {
1002                                         $networks = Protocol::FEDERATED;
1003                                         $condition = ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
1004                                                 'network' => $networks, 'archive' => false, 'pending' => false, 'uid' => $contact['uid']];
1005
1006                                         // Forum posts are only accepted from forum contacts
1007                                         if ($contact['contact-type'] == Contact::TYPE_COMMUNITY) {
1008                                                 $condition['rel'] = [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER];
1009                                         }
1010
1011                                         if (!DBA::exists('contact', $condition)) {
1012                                                 continue;
1013                                         }
1014                                 }
1015
1016                                 $type = $receivers[$contact['uid']]['type'] ?? self::TARGET_UNKNOWN;
1017                                 if (in_array($type, [self::TARGET_UNKNOWN, self::TARGET_FOLLOWER, self::TARGET_ANSWER, self::TARGET_GLOBAL])) {
1018                                         switch ($element) {
1019                                                 case 'as:to':
1020                                                         $type = self::TARGET_TO;
1021                                                         break;
1022                                                 case 'as:cc':
1023                                                         $type = self::TARGET_CC;
1024                                                         break;
1025                                                 case 'as:bto':
1026                                                         $type = self::TARGET_BTO;
1027                                                         break;
1028                                                 case 'as:bcc':
1029                                                         $type = self::TARGET_BCC;
1030                                                         break;
1031                                         }
1032
1033                                         $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $type];
1034                                 }
1035                         }
1036                 }
1037
1038                 self::switchContacts($receivers, $actor);
1039
1040                 return $receivers;
1041         }
1042
1043         /**
1044          * Fetch the receiver list of a given actor
1045          *
1046          * @param string  $actor
1047          * @param array   $tags
1048          * @param array   $receivers
1049          * @param integer $target_type
1050          * @param array   $profile
1051          *
1052          * @return array with receivers (user id)
1053          * @throws \Exception
1054          */
1055         private static function getReceiverForActor(string $actor, array $tags, array $receivers, int $target_type, array $profile): array
1056         {
1057                 $basecondition = ['rel' => [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER],
1058                         'network' => Protocol::FEDERATED, 'archive' => false, 'pending' => false];
1059
1060                 if (!empty($profile['uri-id'])) {
1061                         $condition = DBA::mergeConditions($basecondition, ["`uri-id` = ? AND `uid` != ?", $profile['uri-id'], 0]);
1062                         $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
1063                         while ($contact = DBA::fetch($contacts)) {
1064                                 if (empty($receivers[$contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
1065                                         $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $target_type];
1066                                 }
1067                         }
1068                         DBA::close($contacts);
1069                 } else {
1070                         // This part will only be called while post update 1426 wasn't finished
1071                         $condition = DBA::mergeConditions($basecondition, ["`nurl` = ? AND `uid` != ?", Strings::normaliseLink($actor), 0]);
1072                         $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
1073                         while ($contact = DBA::fetch($contacts)) {
1074                                 if (empty($receivers[$contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
1075                                         $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $target_type];
1076                                 }
1077                         }
1078                         DBA::close($contacts);
1079
1080                         // The queries are split because of performance issues
1081                         $condition = DBA::mergeConditions($basecondition, ["`alias` IN (?, ?) AND `uid` != ?", Strings::normaliseLink($actor), $actor, 0]);
1082                         $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
1083                         while ($contact = DBA::fetch($contacts)) {
1084                                 if (empty($receivers[$contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
1085                                         $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $target_type];
1086                                 }
1087                         }
1088                         DBA::close($contacts);
1089                 }
1090                 return $receivers;
1091         }
1092
1093         /**
1094          * Tests if the contact is a valid receiver for this actor
1095          *
1096          * @param array  $contact
1097          * @param array  $tags
1098          *
1099          * @return bool with receivers (user id)
1100          * @throws \Exception
1101          */
1102         private static function isValidReceiverForActor(array $contact, array $tags): bool
1103         {
1104                 // Are we following the contact? Then this is a valid receiver
1105                 if (in_array($contact['rel'], [Contact::SHARING, Contact::FRIEND])) {
1106                         return true;
1107                 }
1108
1109                 // When the possible receiver isn't a community, then it is no valid receiver
1110                 $owner = User::getOwnerDataById($contact['uid']);
1111                 if (empty($owner) || ($owner['contact-type'] != Contact::TYPE_COMMUNITY)) {
1112                         return false;
1113                 }
1114
1115                 // Is the community account tagged?
1116                 foreach ($tags as $tag) {
1117                         if ($tag['type'] != 'Mention') {
1118                                 continue;
1119                         }
1120
1121                         if (Strings::compareLink($tag['href'], $owner['url'])) {
1122                                 return true;
1123                         }
1124                 }
1125
1126                 return false;
1127         }
1128
1129         /**
1130          * Switches existing contacts to ActivityPub
1131          *
1132          * @param integer $cid Contact ID
1133          * @param integer $uid User ID
1134          * @param string  $url Profile URL
1135          * @return void
1136          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1137          * @throws \ImagickException
1138          */
1139         public static function switchContact(int $cid, int $uid, string $url)
1140         {
1141                 if (DBA::exists('contact', ['id' => $cid, 'network' => Protocol::ACTIVITYPUB])) {
1142                         Logger::info('Contact is already ActivityPub', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
1143                         return;
1144                 }
1145
1146                 if (Contact::updateFromProbe($cid)) {
1147                         Logger::info('Update was successful', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
1148                 }
1149
1150                 // Send a new follow request to be sure that the connection still exists
1151                 if (($uid != 0) && DBA::exists('contact', ['id' => $cid, 'rel' => [Contact::SHARING, Contact::FRIEND], 'network' => Protocol::ACTIVITYPUB])) {
1152                         Logger::info('Contact had been switched to ActivityPub. Sending a new follow request.', ['uid' => $uid, 'url' => $url]);
1153                         ActivityPub\Transmitter::sendActivity('Follow', $url, $uid);
1154                 }
1155         }
1156
1157         /**
1158          * @TODO Fix documentation and type-hints
1159          *
1160          * @param $receivers
1161          * @param $actor
1162          * @return void
1163          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1164          * @throws \ImagickException
1165          */
1166         private static function switchContacts($receivers, $actor)
1167         {
1168                 if (empty($actor)) {
1169                         return;
1170                 }
1171
1172                 foreach ($receivers as $receiver) {
1173                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver['uid'], 'network' => Protocol::OSTATUS, 'nurl' => Strings::normaliseLink($actor)]);
1174                         if (DBA::isResult($contact)) {
1175                                 self::switchContact($contact['id'], $receiver['uid'], $actor);
1176                         }
1177
1178                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver['uid'], 'network' => Protocol::OSTATUS, 'alias' => [Strings::normaliseLink($actor), $actor]]);
1179                         if (DBA::isResult($contact)) {
1180                                 self::switchContact($contact['id'], $receiver['uid'], $actor);
1181                         }
1182                 }
1183         }
1184
1185         /**
1186          * @TODO Fix documentation and type-hints
1187          *
1188          * @param       $object_data
1189          * @param array $activity
1190          *
1191          * @return mixed
1192          */
1193         private static function addActivityFields($object_data, array $activity)
1194         {
1195                 if (!empty($activity['published']) && empty($object_data['published'])) {
1196                         $object_data['published'] = JsonLD::fetchElement($activity, 'as:published', '@value');
1197                 }
1198
1199                 if (!empty($activity['diaspora:guid']) && empty($object_data['diaspora:guid'])) {
1200                         $object_data['diaspora:guid'] = JsonLD::fetchElement($activity, 'diaspora:guid', '@value');
1201                 }
1202
1203                 $object_data['service'] = JsonLD::fetchElement($activity, 'as:instrument', 'as:name', '@type', 'as:Service');
1204                 $object_data['service'] = JsonLD::fetchElement($object_data, 'service', '@value');
1205
1206                 if (!empty($object_data['object_id'])) {
1207                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
1208                         $objectId = Item::getURIByLink($object_data['object_id']);
1209                         if (!empty($objectId) && ($object_data['object_id'] != $objectId)) {
1210                                 Logger::notice('Fix wrong object-id', ['received' => $object_data['object_id'], 'correct' => $objectId]);
1211                                 $object_data['object_id'] = $objectId;
1212                         }
1213                 }
1214
1215                 return $object_data;
1216         }
1217
1218         /**
1219          * Fetches the object data from external ressources if needed
1220          *
1221          * @param string  $object_id    Object ID of the the provided object
1222          * @param array   $object       The provided object array
1223          * @param boolean $trust_source Do we trust the provided object?
1224          * @param integer $uid          User ID for the signature that we use to fetch data
1225          *
1226          * @return array|false with trusted and valid object data
1227          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1228          * @throws \ImagickException
1229          */
1230         private static function fetchObject(string $object_id, array $object = [], bool $trust_source = false, int $uid = 0)
1231         {
1232                 // By fetching the type we check if the object is complete.
1233                 $type = JsonLD::fetchElement($object, '@type');
1234
1235                 if (!$trust_source || empty($type)) {
1236                         $data = ActivityPub::fetchContent($object_id, $uid);
1237                         if (!empty($data)) {
1238                                 $object = JsonLD::compact($data);
1239                                 Logger::info('Fetched content for ' . $object_id);
1240                         } else {
1241                                 Logger::info('Empty content for ' . $object_id . ', check if content is available locally.');
1242
1243                                 $item = Post::selectFirst(Item::DELIVER_FIELDLIST, ['uri' => $object_id]);
1244                                 if (!DBA::isResult($item)) {
1245                                         Logger::info('Object with url ' . $object_id . ' was not found locally.');
1246                                         return false;
1247                                 }
1248                                 Logger::info('Using already stored item for url ' . $object_id);
1249                                 $data = ActivityPub\Transmitter::createNote($item);
1250                                 $object = JsonLD::compact($data);
1251                         }
1252
1253                         $id = JsonLD::fetchElement($object, '@id');
1254                         if (empty($id)) {
1255                                 Logger::info('Empty id');
1256                                 return false;
1257                         }
1258
1259                         if ($id != $object_id) {
1260                                 Logger::info('Fetched id differs from provided id', ['provided' => $object_id, 'fetched' => $id]);
1261                                 return false;
1262                         }
1263                 } else {
1264                         Logger::info('Using original object for url ' . $object_id);
1265                 }
1266
1267                 $type = JsonLD::fetchElement($object, '@type');
1268                 if (empty($type)) {
1269                         Logger::info('Empty type');
1270                         return false;
1271                 }
1272
1273                 // Lemmy is resharing "create" activities instead of content
1274                 // We fetch the content from the activity.
1275                 if (in_array($type, ['as:Create'])) {
1276                         $object = $object['as:object'];
1277                         $type = JsonLD::fetchElement($object, '@type');
1278                         if (empty($type)) {
1279                                 Logger::info('Empty type');
1280                                 return false;
1281                         }
1282                         $object_data = self::processObject($object);
1283                 }
1284
1285                 // We currently don't handle 'pt:CacheFile', but with this step we avoid logging
1286                 if (in_array($type, self::CONTENT_TYPES) || ($type == 'pt:CacheFile')) {
1287                         $object_data = self::processObject($object);
1288
1289                         if (!empty($data)) {
1290                                 $object_data['raw'] = json_encode($data);
1291                         }
1292                         return $object_data;
1293                 }
1294
1295                 if ($type == 'as:Announce') {
1296                         $object_id = JsonLD::fetchElement($object, 'object', '@id');
1297                         if (empty($object_id) || !is_string($object_id)) {
1298                                 return false;
1299                         }
1300                         return self::fetchObject($object_id, [], false, $uid);
1301                 }
1302
1303                 Logger::info('Unhandled object type: ' . $type);
1304                 return false;
1305         }
1306
1307         /**
1308          * Converts the language element (Used by Peertube)
1309          *
1310          * @param array $languages
1311          * @return array Languages
1312          */
1313         public static function processLanguages(array $languages): array
1314         {
1315                 if (empty($languages)) {
1316                         return [];
1317                 }
1318
1319                 $language_list = [];
1320
1321                 foreach ($languages as $language) {
1322                         if (!empty($language['_:identifier']) && !empty($language['as:name'])) {
1323                                 $language_list[$language['_:identifier']] = $language['as:name'];
1324                         }
1325                 }
1326                 return $language_list;
1327         }
1328
1329         /**
1330          * Convert tags from JSON-LD format into a simplified format
1331          *
1332          * @param array $tags Tags in JSON-LD format
1333          *
1334          * @return array with tags in a simplified format
1335          */
1336         public static function processTags(array $tags): array
1337         {
1338                 $taglist = [];
1339
1340                 foreach ($tags as $tag) {
1341                         if (empty($tag)) {
1342                                 continue;
1343                         }
1344
1345                         $element = ['type' => str_replace('as:', '', JsonLD::fetchElement($tag, '@type')),
1346                                 'href' => JsonLD::fetchElement($tag, 'as:href', '@id'),
1347                                 'name' => JsonLD::fetchElement($tag, 'as:name', '@value')];
1348
1349                         if (empty($element['type'])) {
1350                                 continue;
1351                         }
1352
1353                         if (empty($element['href'])) {
1354                                 $element['href'] = $element['name'];
1355                         }
1356
1357                         $taglist[] = $element;
1358                 }
1359                 return $taglist;
1360         }
1361
1362         /**
1363          * Convert emojis from JSON-LD format into a simplified format
1364          *
1365          * @param array $emojis
1366          * @return array with emojis in a simplified format
1367          */
1368         private static function processEmojis(array $emojis): array
1369         {
1370                 $emojilist = [];
1371
1372                 foreach ($emojis as $emoji) {
1373                         if (empty($emoji) || (JsonLD::fetchElement($emoji, '@type') != 'toot:Emoji') || empty($emoji['as:icon'])) {
1374                                 continue;
1375                         }
1376
1377                         $url = JsonLD::fetchElement($emoji['as:icon'], 'as:url', '@id');
1378                         $element = ['name' => JsonLD::fetchElement($emoji, 'as:name', '@value'),
1379                                 'href' => $url];
1380
1381                         $emojilist[] = $element;
1382                 }
1383
1384                 return $emojilist;
1385         }
1386
1387         /**
1388          * Convert attachments from JSON-LD format into a simplified format
1389          *
1390          * @param array $attachments Attachments in JSON-LD format
1391          *
1392          * @return array Attachments in a simplified format
1393          */
1394         private static function processAttachments(array $attachments): array
1395         {
1396                 $attachlist = [];
1397
1398                 // Removes empty values
1399                 $attachments = array_filter($attachments);
1400
1401                 foreach ($attachments as $attachment) {
1402                         switch (JsonLD::fetchElement($attachment, '@type')) {
1403                                 case 'as:Page':
1404                                         $pageUrl = null;
1405                                         $pageImage = null;
1406
1407                                         $urls = JsonLD::fetchElementArray($attachment, 'as:url');
1408                                         foreach ($urls as $url) {
1409                                                 // Single scalar URL case
1410                                                 if (is_string($url)) {
1411                                                         $pageUrl = $url;
1412                                                         continue;
1413                                                 }
1414
1415                                                 $href = JsonLD::fetchElement($url, 'as:href', '@id');
1416                                                 $mediaType = JsonLD::fetchElement($url, 'as:mediaType', '@value');
1417                                                 if (Strings::startsWith($mediaType, 'image')) {
1418                                                         $pageImage = $href;
1419                                                 } else {
1420                                                         $pageUrl = $href;
1421                                                 }
1422                                         }
1423
1424                                         $attachlist[] = [
1425                                                 'type'  => 'link',
1426                                                 'title' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1427                                                 'desc'  => JsonLD::fetchElement($attachment, 'as:summary', '@value'),
1428                                                 'url'   => $pageUrl,
1429                                                 'image' => $pageImage,
1430                                         ];
1431                                         break;
1432                                 case 'as:Image':
1433                                         $mediaType = JsonLD::fetchElement($attachment, 'as:mediaType', '@value');
1434                                         $imageFullUrl = JsonLD::fetchElement($attachment, 'as:url', '@id');
1435                                         $imagePreviewUrl = null;
1436                                         // Multiple URLs?
1437                                         if (!$imageFullUrl && ($urls = JsonLD::fetchElementArray($attachment, 'as:url'))) {
1438                                                 $imageVariants = [];
1439                                                 $previewVariants = [];
1440                                                 foreach ($urls as $url) {
1441                                                         // Scalar URL, no discrimination possible
1442                                                         if (is_string($url)) {
1443                                                                 $imageFullUrl = $url;
1444                                                                 continue;
1445                                                         }
1446
1447                                                         // Not sure what to do with a different Link media type than the base Image, we skip
1448                                                         if ($mediaType != JsonLD::fetchElement($url, 'as:mediaType', '@value')) {
1449                                                                 continue;
1450                                                         }
1451
1452                                                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1453
1454                                                         // Default URL choice if no discriminating width is provided
1455                                                         $imageFullUrl = $href ?? $imageFullUrl;
1456
1457                                                         $width = intval(JsonLD::fetchElement($url, 'as:width', '@value') ?? 1);
1458
1459                                                         if ($href && $width) {
1460                                                                 $imageVariants[$width] = $href;
1461                                                                 // 632 is the ideal width for full screen frio posts, we compute the absolute distance to it
1462                                                                 $previewVariants[abs(632 - $width)] = $href;
1463                                                         }
1464                                                 }
1465
1466                                                 if ($imageVariants) {
1467                                                         // Taking the maximum size image
1468                                                         ksort($imageVariants);
1469                                                         $imageFullUrl = array_pop($imageVariants);
1470
1471                                                         // Taking the minimum number distance to the target distance
1472                                                         ksort($previewVariants);
1473                                                         $imagePreviewUrl = array_shift($previewVariants);
1474                                                 }
1475
1476                                                 unset($imageVariants);
1477                                                 unset($previewVariants);
1478                                         }
1479
1480                                         $attachlist[] = [
1481                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1482                                                 'mediaType' => $mediaType,
1483                                                 'name'  => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1484                                                 'url'   => $imageFullUrl,
1485                                                 'image' => $imagePreviewUrl !== $imageFullUrl ? $imagePreviewUrl : null,
1486                                         ];
1487                                         break;
1488                                 default:
1489                                         $attachlist[] = [
1490                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1491                                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType', '@value'),
1492                                                 'name' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1493                                                 'url' => JsonLD::fetchElement($attachment, 'as:url', '@id'),
1494                                                 'height' => JsonLD::fetchElement($attachment, 'as:height', '@value'),
1495                                                 'width' => JsonLD::fetchElement($attachment, 'as:width', '@value'),
1496                                                 'image' => JsonLD::fetchElement($attachment, 'as:image', '@id')
1497                                         ];
1498                         }
1499                 }
1500
1501                 return $attachlist;
1502         }
1503
1504         /**
1505          * Convert questions from JSON-LD format into a simplified format
1506          *
1507          * @param array $object
1508          *
1509          * @return array Questions in a simplified format
1510          */
1511         private static function processQuestion(array $object): array
1512         {
1513                 $question = [];
1514
1515                 if (!empty($object['as:oneOf'])) {
1516                         $question['multiple'] = false;
1517                         $options = JsonLD::fetchElementArray($object, 'as:oneOf') ?? [];
1518                 } elseif (!empty($object['as:anyOf'])) {
1519                         $question['multiple'] = true;
1520                         $options = JsonLD::fetchElementArray($object, 'as:anyOf') ?? [];
1521                 } else {
1522                         return [];
1523                 }
1524
1525                 $closed = JsonLD::fetchElement($object, 'as:closed', '@value');
1526                 if (!empty($closed)) {
1527                         $question['end-time'] = $closed;
1528                 } else {
1529                         $question['end-time'] = JsonLD::fetchElement($object, 'as:endTime', '@value');
1530                 }
1531
1532                 $question['voters']  = (int)JsonLD::fetchElement($object, 'toot:votersCount', '@value');
1533                 $question['options'] = [];
1534
1535                 $voters = 0;
1536
1537                 foreach ($options as $option) {
1538                         if (JsonLD::fetchElement($option, '@type') != 'as:Note') {
1539                                 continue;
1540                         }
1541
1542                         $name = JsonLD::fetchElement($option, 'as:name', '@value');
1543
1544                         if (empty($option['as:replies'])) {
1545                                 continue;
1546                         }
1547
1548                         $replies = JsonLD::fetchElement($option['as:replies'], 'as:totalItems', '@value');
1549
1550                         $question['options'][] = ['name' => $name, 'replies' => $replies];
1551
1552                         $voters += (int)$replies;
1553                 }
1554
1555                 // For single choice question we can count the number of voters if not provided (like with Misskey)
1556                 if (empty($question['voters']) && !$question['multiple']) {
1557                         $question['voters'] = $voters;
1558                 }
1559
1560                 return $question;
1561         }
1562
1563         /**
1564          * Fetch the original source or content with the "language" Markdown or HTML
1565          *
1566          * @param array $object
1567          * @param array $object_data
1568          *
1569          * @return array Object data (?)
1570          * @throws \Exception
1571          */
1572         private static function getSource(array $object, array $object_data): array
1573         {
1574                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/bbcode');
1575                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1576                 if (!empty($object_data['source'])) {
1577                         return $object_data;
1578                 }
1579
1580                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/markdown');
1581                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1582                 if (!empty($object_data['source'])) {
1583                         $object_data['source'] = Markdown::toBBCode($object_data['source']);
1584                         return $object_data;
1585                 }
1586
1587                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/html');
1588                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1589                 if (!empty($object_data['source'])) {
1590                         $object_data['source'] = HTML::toBBCode($object_data['source']);
1591                         return $object_data;
1592                 }
1593
1594                 return $object_data;
1595         }
1596
1597         /**
1598          * Extracts a potential alternate URL from a list of additional URL elements
1599          *
1600          * @param array $urls
1601          * @return string
1602          */
1603         private static function extractAlternateUrl(array $urls): string
1604         {
1605                 $alternateUrl = '';
1606                 foreach ($urls as $key => $url) {
1607                         // Not a list but a single URL element
1608                         if (!is_numeric($key)) {
1609                                 continue;
1610                         }
1611
1612                         if (empty($url['@type']) || ($url['@type'] != 'as:Link')) {
1613                                 continue;
1614                         }
1615
1616                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1617                         if (empty($href)) {
1618                                 continue;
1619                         }
1620
1621                         $mediatype = JsonLD::fetchElement($url, 'as:mediaType');
1622                         if (empty($mediatype)) {
1623                                 continue;
1624                         }
1625
1626                         if ($mediatype == 'text/html') {
1627                                 $alternateUrl = $href;
1628                         }
1629                 }
1630
1631                 return $alternateUrl;
1632         }
1633
1634         /**
1635          * Check if the "as:url" element is an array with multiple links
1636          * This is the case with audio and video posts.
1637          * Then the links are added as attachments
1638          *
1639          * @param array $urls The object URL list
1640          * @return array an array of attachments
1641          */
1642         private static function processAttachmentUrls(array $urls): array
1643         {
1644                 $attachments = [];
1645                 foreach ($urls as $key => $url) {
1646                         // Not a list but a single URL element
1647                         if (!is_numeric($key)) {
1648                                 continue;
1649                         }
1650
1651                         if (empty($url['@type']) || ($url['@type'] != 'as:Link')) {
1652                                 continue;
1653                         }
1654
1655                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1656                         if (empty($href)) {
1657                                 continue;
1658                         }
1659
1660                         $mediatype = JsonLD::fetchElement($url, 'as:mediaType');
1661                         if (empty($mediatype)) {
1662                                 continue;
1663                         }
1664
1665                         $filetype = strtolower(substr($mediatype, 0, strpos($mediatype, '/')));
1666
1667                         if ($filetype == 'audio') {
1668                                 $attachments[] = ['type' => $filetype, 'mediaType' => $mediatype, 'url' => $href, 'height' => null, 'size' => null, 'name' => ''];
1669                         } elseif ($filetype == 'video') {
1670                                 $height = (int)JsonLD::fetchElement($url, 'as:height', '@value');
1671                                 // PeerTube audio-only track
1672                                 if ($height === 0) {
1673                                         continue;
1674                                 }
1675
1676                                 $size = (int)JsonLD::fetchElement($url, 'pt:size', '@value');
1677                                 $attachments[] = ['type' => $filetype, 'mediaType' => $mediatype, 'url' => $href, 'height' => $height, 'size' => $size, 'name' => ''];
1678                         } elseif (in_array($mediatype, ['application/x-bittorrent', 'application/x-bittorrent;x-scheme-handler/magnet'])) {
1679                                 $height = (int)JsonLD::fetchElement($url, 'as:height', '@value');
1680
1681                                 // For Torrent links we always store the highest resolution
1682                                 if (!empty($attachments[$mediatype]['height']) && ($height < $attachments[$mediatype]['height'])) {
1683                                         continue;
1684                                 }
1685
1686                                 $attachments[$mediatype] = ['type' => $mediatype, 'mediaType' => $mediatype, 'url' => $href, 'height' => $height, 'size' => null, 'name' => ''];
1687                         } elseif ($mediatype == 'application/x-mpegURL') {
1688                                 // PeerTube exception, actual video link is in the tags of this URL element
1689                                 $attachments = array_merge($attachments, self::processAttachmentUrls($url['as:tag']));
1690                         }
1691                 }
1692
1693                 return array_values($attachments);
1694         }
1695
1696         /**
1697          * Fetches data from the object part of an activity
1698          *
1699          * @param array $object
1700          *
1701          * @return array|bool Object data or FALSE if $object does not contain @id element
1702          * @throws \Exception
1703          */
1704         private static function processObject(array $object)
1705         {
1706                 if (!JsonLD::fetchElement($object, '@id')) {
1707                         return false;
1708                 }
1709
1710                 $object_data = [];
1711                 $object_data['object_type'] = JsonLD::fetchElement($object, '@type');
1712                 $object_data['id'] = JsonLD::fetchElement($object, '@id');
1713                 $object_data['reply-to-id'] = JsonLD::fetchElement($object, 'as:inReplyTo', '@id');
1714
1715                 // An empty "id" field is translated to "./" by the compactor, so we have to check for this content
1716                 if (empty($object_data['reply-to-id']) || ($object_data['reply-to-id'] == './')) {
1717                         $object_data['reply-to-id'] = $object_data['id'];
1718
1719                         // On activities the "reply to" is the id of the object it refers to
1720                         if (in_array($object_data['object_type'], self::ACTIVITY_TYPES)) {
1721                                 $object_id = JsonLD::fetchElement($object, 'as:object', '@id');
1722                                 if (!empty($object_id)) {
1723                                         $object_data['reply-to-id'] = $object_id;
1724                                 }
1725                         }
1726                 } else {
1727                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
1728                         $replyToId = Item::getURIByLink($object_data['reply-to-id']);
1729                         if (!empty($replyToId) && ($object_data['reply-to-id'] != $replyToId)) {
1730                                 Logger::notice('Fix wrong reply-to', ['received' => $object_data['reply-to-id'], 'correct' => $replyToId]);
1731                                 $object_data['reply-to-id'] = $replyToId;
1732                         }
1733                 }
1734
1735                 $object_data['published'] = JsonLD::fetchElement($object, 'as:published', '@value');
1736                 $object_data['updated'] = JsonLD::fetchElement($object, 'as:updated', '@value');
1737
1738                 if (empty($object_data['updated'])) {
1739                         $object_data['updated'] = $object_data['published'];
1740                 }
1741
1742                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
1743                         $object_data['published'] = $object_data['updated'];
1744                 }
1745
1746                 $actor = JsonLD::fetchElement($object, 'as:attributedTo', '@id');
1747                 if (empty($actor)) {
1748                         $actor = JsonLD::fetchElement($object, 'as:actor', '@id');
1749                 }
1750
1751                 $location = JsonLD::fetchElement($object, 'as:location', 'as:name', '@type', 'as:Place');
1752                 $location = JsonLD::fetchElement($location, 'location', '@value');
1753                 if ($location) {
1754                         // Some AP software allow formatted text in post location, so we run all the text converters we have to boil
1755                         // down to HTML and then finally format to plaintext.
1756                         $location = Markdown::convert($location);
1757                         $location = BBCode::toPlaintext($location);
1758                 }
1759
1760                 $object_data['sc:identifier'] = JsonLD::fetchElement($object, 'sc:identifier', '@value');
1761                 $object_data['diaspora:guid'] = JsonLD::fetchElement($object, 'diaspora:guid', '@value');
1762                 $object_data['diaspora:comment'] = JsonLD::fetchElement($object, 'diaspora:comment', '@value');
1763                 $object_data['diaspora:like'] = JsonLD::fetchElement($object, 'diaspora:like', '@value');
1764                 $object_data['actor'] = $object_data['author'] = $actor;
1765                 $object_data['context'] = JsonLD::fetchElement($object, 'as:context', '@id');
1766                 $object_data['conversation'] = JsonLD::fetchElement($object, 'ostatus:conversation', '@id');
1767                 $object_data['sensitive'] = JsonLD::fetchElement($object, 'as:sensitive');
1768                 $object_data['name'] = JsonLD::fetchElement($object, 'as:name', '@value');
1769                 $object_data['summary'] = JsonLD::fetchElement($object, 'as:summary', '@value');
1770                 $object_data['content'] = JsonLD::fetchElement($object, 'as:content', '@value');
1771                 $object_data['mediatype'] = JsonLD::fetchElement($object, 'as:mediaType', '@value');
1772                 $object_data = self::getSource($object, $object_data);
1773                 $object_data['start-time'] = JsonLD::fetchElement($object, 'as:startTime', '@value');
1774                 $object_data['end-time'] = JsonLD::fetchElement($object, 'as:endTime', '@value');
1775                 $object_data['location'] = $location;
1776                 $object_data['latitude'] = JsonLD::fetchElement($object, 'as:location', 'as:latitude', '@type', 'as:Place');
1777                 $object_data['latitude'] = JsonLD::fetchElement($object_data, 'latitude', '@value');
1778                 $object_data['longitude'] = JsonLD::fetchElement($object, 'as:location', 'as:longitude', '@type', 'as:Place');
1779                 $object_data['longitude'] = JsonLD::fetchElement($object_data, 'longitude', '@value');
1780                 $object_data['attachments'] = self::processAttachments(JsonLD::fetchElementArray($object, 'as:attachment') ?? []);
1781                 $object_data['tags'] = self::processTags(JsonLD::fetchElementArray($object, 'as:tag') ?? []);
1782                 $object_data['emojis'] = self::processEmojis(JsonLD::fetchElementArray($object, 'as:tag', null, '@type', 'toot:Emoji') ?? []);
1783                 $object_data['languages'] = self::processLanguages(JsonLD::fetchElementArray($object, 'sc:inLanguage') ?? []);
1784                 $object_data['generator'] = JsonLD::fetchElement($object, 'as:generator', 'as:name', '@type', 'as:Application');
1785                 $object_data['generator'] = JsonLD::fetchElement($object_data, 'generator', '@value');
1786                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'as:url', '@id');
1787
1788                 // Special treatment for Hubzilla links
1789                 if (is_array($object_data['alternate-url'])) {
1790                         $object_data['alternate-url'] = JsonLD::fetchElement($object_data['alternate-url'], 'as:href', '@id');
1791
1792                         if (!is_string($object_data['alternate-url'])) {
1793                                 $object_data['alternate-url'] = JsonLD::fetchElement($object['as:url'], 'as:href', '@id');
1794                         }
1795                 }
1796
1797                 if (!empty($object_data['alternate-url']) && !Network::isValidHttpUrl($object_data['alternate-url'])) {
1798                         $object_data['alternate-url'] = null;
1799                 }
1800
1801                 if (in_array($object_data['object_type'], ['as:Audio', 'as:Video'])) {
1802                         $object_data['alternate-url'] = self::extractAlternateUrl($object['as:url'] ?? []) ?: $object_data['alternate-url'];
1803                         $object_data['attachments'] = array_merge($object_data['attachments'], self::processAttachmentUrls($object['as:url'] ?? []));
1804                 }
1805
1806                 // For page types we expect that the alternate url posts to some page.
1807                 // So we add this to the attachments if it differs from the id.
1808                 // Currently only Lemmy is using the page type.
1809                 if (($object_data['object_type'] == 'as:Page') && !empty($object_data['alternate-url']) && !Strings::compareLink($object_data['alternate-url'], $object_data['id'])) {
1810                         $object_data['attachments'][] = ['url' => $object_data['alternate-url']];
1811                         $object_data['alternate-url'] = null;
1812                 }
1813
1814                 if ($object_data['object_type'] == 'as:Question') {
1815                         $object_data['question'] = self::processQuestion($object);
1816                 }
1817
1818                 $receiverdata = self::getReceivers($object, $object_data['actor'] ?? '', $object_data['tags'], true);
1819                 $receivers = $reception_types = [];
1820                 foreach ($receiverdata as $key => $data) {
1821                         $receivers[$key] = $data['uid'];
1822                         $reception_types[$data['uid']] = $data['type'] ?? 0;
1823                 }
1824
1825                 $object_data['receiver_urls']  = self::getReceiverURL($object);
1826                 $object_data['receiver']       = $receivers;
1827                 $object_data['reception_type'] = $reception_types;
1828
1829                 $object_data['unlisted'] = in_array(-1, $object_data['receiver']);
1830                 unset($object_data['receiver'][-1]);
1831                 unset($object_data['reception_type'][-1]);
1832
1833                 // Common object data:
1834
1835                 // Unhandled
1836                 // @context, type, actor, signature, mediaType, duration, replies, icon
1837
1838                 // Also missing: (Defined in the standard, but currently unused)
1839                 // audience, preview, endTime, startTime, image
1840
1841                 // Data in Notes:
1842
1843                 // Unhandled
1844                 // contentMap, announcement_count, announcements, context_id, likes, like_count
1845                 // inReplyToStatusId, shares, quoteUrl, statusnetConversationId
1846
1847                 // Data in video:
1848
1849                 // To-Do?
1850                 // category, licence, language, commentsEnabled
1851
1852                 // Unhandled
1853                 // views, waitTranscoding, state, support, subtitleLanguage
1854                 // likes, dislikes, shares, comments
1855
1856                 return $object_data;
1857         }
1858 }