src/Protocol/ActivityPub/Receiver.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2020, Friendica
   4  *
   5  * @license GNU AGPL version 3 or any later version
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU Affero General Public License as
   9  * published by the Free Software Foundation, either version 3 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU Affero General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Affero General Public License
  18  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  19  *
  20  */
  21
  22 namespace Friendica\Protocol\ActivityPub;
  23
  24 use Friendica\Content\Text\BBCode;
  25 use Friendica\Database\DBA;
  26 use Friendica\Content\Text\HTML;
  27 use Friendica\Content\Text\Markdown;
  28 use Friendica\Core\Logger;
  29 use Friendica\Core\Protocol;
  30 use Friendica\Model\Contact;
  31 use Friendica\Model\APContact;
  32 use Friendica\Model\Item;
  33 use Friendica\Model\Post;
  34 use Friendica\Model\User;
  35 use Friendica\Protocol\Activity;
  36 use Friendica\Protocol\ActivityPub;
  37 use Friendica\Util\HTTPSignature;
  38 use Friendica\Util\JsonLD;
  39 use Friendica\Util\LDSignature;
  40 use Friendica\Util\Strings;
  41
  42 /**
  43  * ActivityPub Receiver Protocol class
  44  *
  45  * To-Do:
  46  * @todo Undo Announce
  47  *
  48  * Check what this is meant to do:
  49  * - Add
  50  * - Block
  51  * - Flag
  52  * - Remove
  53  * - Undo Block
  54  */
  55 class Receiver
  56 {
  57         const PUBLIC_COLLECTION = 'as:Public';
  58         const ACCOUNT_TYPES = ['as:Person', 'as:Organization', 'as:Service', 'as:Group', 'as:Application'];
  59         const CONTENT_TYPES = ['as:Note', 'as:Article', 'as:Video', 'as:Image', 'as:Event', 'as:Audio'];
  60         const ACTIVITY_TYPES = ['as:Like', 'as:Dislike', 'as:Accept', 'as:Reject', 'as:TentativeAccept'];
  61
  62         const TARGET_UNKNOWN = 0;
  63         const TARGET_TO = 1;
  64         const TARGET_CC = 2;
  65         const TARGET_BTO = 3;
  66         const TARGET_BCC = 4;
  67         const TARGET_FOLLOWER = 5;
  68         const TARGET_ANSWER = 6;
  69         const TARGET_GLOBAL = 7;
  70
  71         /**
  72          * Checks if the web request is done for the AP protocol
  73          *
  74          * @return bool is it AP?
  75          */
  76         public static function isRequest()
  77         {
  78                 return stristr($_SERVER['HTTP_ACCEPT'] ?? '', 'application/activity+json') ||
  79                         stristr($_SERVER['HTTP_ACCEPT'] ?? '', 'application/ld+json');
  80         }
  81
  82         /**
  83          * Checks incoming message from the inbox
  84          *
  85          * @param         $body
  86          * @param         $header
  87          * @param integer $uid User ID
  88          * @throws \Exception
  89          */
  90         public static function processInbox($body, $header, $uid)
  91         {
  92                 $activity = json_decode($body, true);
  93                 if (empty($activity)) {
  94                         Logger::warning('Invalid body.');
  95                         return;
  96                 }
  97
  98                 $ldactivity = JsonLD::compact($activity);
  99
 100                 $actor = JsonLD::fetchElement($ldactivity, 'as:actor', '@id');
 101
 102                 $apcontact = APContact::getByURL($actor);
 103                 if (empty($apcontact)) {
 104                         Logger::notice('Unable to retrieve AP contact for actor', ['actor' => $actor]);
 105                 } elseif ($apcontact['type'] == 'Application' && $apcontact['nick'] == 'relay') {
 106                         self::processRelayPost($ldactivity, $actor);
 107                         return;
 108                 } else {
 109                         APContact::unmarkForArchival($apcontact);
 110                 }
 111
 112                 $http_signer = HTTPSignature::getSigner($body, $header);
 113                 if (empty($http_signer)) {
 114                         Logger::warning('Invalid HTTP signature, message will be discarded.');
 115                         return;
 116                 } else {
 117                         Logger::info('Valid HTTP signature', ['signer' => $http_signer]);
 118                 }
 119
 120                 $signer = [$http_signer];
 121
 122                 Logger::info('Message for user ' . $uid . ' is from actor ' . $actor);
 123
 124                 if (LDSignature::isSigned($activity)) {
 125                         $ld_signer = LDSignature::getSigner($activity);
 126                         if (empty($ld_signer)) {
 127                                 Logger::log('Invalid JSON-LD signature from ' . $actor, Logger::DEBUG);
 128                         } elseif ($ld_signer != $http_signer) {
 129                                 $signer[] = $ld_signer;
 130                         }
 131                         if (!empty($ld_signer && ($actor == $http_signer))) {
 132                                 Logger::log('The HTTP and the JSON-LD signature belong to ' . $ld_signer, Logger::DEBUG);
 133                                 $trust_source = true;
 134                         } elseif (!empty($ld_signer)) {
 135                                 Logger::log('JSON-LD signature is signed by ' . $ld_signer, Logger::DEBUG);
 136                                 $trust_source = true;
 137                         } elseif ($actor == $http_signer) {
 138                                 Logger::log('Bad JSON-LD signature, but HTTP signer fits the actor.', Logger::DEBUG);
 139                                 $trust_source = true;
 140                         } else {
 141                                 Logger::log('Invalid JSON-LD signature and the HTTP signer is different.', Logger::DEBUG);
 142                                 $trust_source = false;
 143                         }
 144                 } elseif ($actor == $http_signer) {
 145                         Logger::log('Trusting post without JSON-LD signature, The actor fits the HTTP signer.', Logger::DEBUG);
 146                         $trust_source = true;
 147                 } else {
 148                         Logger::log('No JSON-LD signature, different actor.', Logger::DEBUG);
 149                         $trust_source = false;
 150                 }
 151
 152                 self::processActivity($ldactivity, $body, $uid, $trust_source, true, $signer);
 153         }
 154
 155         /**
 156          * Process incoming posts from relays
 157          *
 158          * @param array  $activity
 159          * @param string $actor
 160          * @return void
 161          */
 162         private static function processRelayPost(array $activity, string $actor)
 163         {
 164                 $type = JsonLD::fetchElement($activity, '@type');
 165                 if (!$type) {
 166                         Logger::info('Empty type', ['activity' => $activity]);
 167                         return;
 168                 }
 169
 170                 if ($type != 'as:Announce') {
 171                         Logger::info('Not an announcement', ['activity' => $activity]);
 172                         return;
 173                 }
 174
 175                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 176                 if (empty($object_id)) {
 177                         Logger::info('No object id found', ['activity' => $activity]);
 178                         return;
 179                 }
 180
 181                 $contact = Contact::getByURL($actor);
 182                 if (empty($contact)) {
 183                         Logger::info('Relay contact not found', ['actor' => $actor]);
 184                         return;
 185                 }
 186
 187                 if (!in_array($contact['rel'], [Contact::SHARING, Contact::FRIEND])) {
 188                         Logger::notice('Relay is no sharer', ['actor' => $actor]);
 189                         return;
 190                 }
 191
 192                 Logger::info('Got relayed message id', ['id' => $object_id]);
 193
 194                 $item_id = Item::searchByLink($object_id);
 195                 if ($item_id) {
 196                         Logger::info('Relayed message already exists', ['id' => $object_id, 'item' => $item_id]);
 197                         return;
 198                 }
 199
 200                 $id = Processor::fetchMissingActivity($object_id, [], $actor);
 201                 if (empty($id)) {
 202                         Logger::notice('Relayed message had not been fetched', ['id' => $object_id]);
 203                         return;
 204                 }
 205
 206                 $item_id = Item::searchByLink($object_id);
 207                 if ($item_id) {
 208                         Logger::info('Relayed message had been fetched and stored', ['id' => $object_id, 'item' => $item_id]);
 209                 } else {
 210                         Logger::notice('Relayed message had not been stored', ['id' => $object_id]);
 211                 }
 212         }
 213
 214         /**
 215          * Fetches the object type for a given object id
 216          *
 217          * @param array   $activity
 218          * @param string  $object_id Object ID of the the provided object
 219          * @param integer $uid       User ID
 220          *
 221          * @return string with object type
 222          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 223          * @throws \ImagickException
 224          */
 225         private static function fetchObjectType($activity, $object_id, $uid = 0)
 226         {
 227                 if (!empty($activity['as:object'])) {
 228                         $object_type = JsonLD::fetchElement($activity['as:object'], '@type');
 229                         if (!empty($object_type)) {
 230                                 return $object_type;
 231                         }
 232                 }
 233
 234                 if (Post::exists(['uri' => $object_id, 'gravity' => [GRAVITY_PARENT, GRAVITY_COMMENT]])) {
 235                         // We just assume "note" since it doesn't make a difference for the further processing
 236                         return 'as:Note';
 237                 }
 238
 239                 $profile = APContact::getByURL($object_id);
 240                 if (!empty($profile['type'])) {
 241                         APContact::unmarkForArchival($profile);
 242                         return 'as:' . $profile['type'];
 243                 }
 244
 245                 $data = ActivityPub::fetchContent($object_id, $uid);
 246                 if (!empty($data)) {
 247                         $object = JsonLD::compact($data);
 248                         $type = JsonLD::fetchElement($object, '@type');
 249                         if (!empty($type)) {
 250                                 return $type;
 251                         }
 252                 }
 253
 254                 return null;
 255         }
 256
 257         /**
 258          * Prepare the object array
 259          *
 260          * @param array   $activity     Array with activity data
 261          * @param integer $uid          User ID
 262          * @param boolean $push         Message had been pushed to our system
 263          * @param boolean $trust_source Do we trust the source?
 264          *
 265          * @return array with object data
 266          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 267          * @throws \ImagickException
 268          */
 269         public static function prepareObjectData($activity, $uid, $push, &$trust_source)
 270         {
 271                 $id = JsonLD::fetchElement($activity, '@id');
 272                 if (!empty($id) && !$trust_source) {
 273                         $fetched_activity = ActivityPub::fetchContent($id, $uid ?? 0);
 274                         if (!empty($fetched_activity)) {
 275                                 $object = JsonLD::compact($fetched_activity);
 276                                 $fetched_id = JsonLD::fetchElement($object, '@id');
 277                                 if ($fetched_id == $id) {
 278                                         Logger::info('Activity had been fetched successfully', ['id' => $id]);
 279                                         $trust_source = true;
 280                                         $activity = $object;
 281                                 } else {
 282                                         Logger::info('Activity id is not equal', ['id' => $id, 'fetched' => $fetched_id]);
 283                                 }
 284                         } else {
 285                                 Logger::info('Activity could not been fetched', ['id' => $id]);
 286                         }
 287                 }
 288
 289                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 290                 if (empty($actor)) {
 291                         Logger::info('Empty actor', ['activity' => $activity]);
 292                         return [];
 293                 }
 294
 295                 $type = JsonLD::fetchElement($activity, '@type');
 296
 297                 // Fetch all receivers from to, cc, bto and bcc
 298                 $receiverdata = self::getReceivers($activity, $actor);
 299                 $receivers = $reception_types = [];
 300                 foreach ($receiverdata as $key => $data) {
 301                         $receivers[$key] = $data['uid'];
 302                         $reception_types[$data['uid']] = $data['type'] ?? self::TARGET_UNKNOWN;
 303                 }
 304
 305                 // When it is a delivery to a personal inbox we add that user to the receivers
 306                 if (!empty($uid)) {
 307                         $additional = [$uid => $uid];
 308                         $receivers = array_replace($receivers, $additional);
 309                         if (empty($activity['thread-completion']) && (empty($reception_types[$uid]) || in_array($reception_types[$uid], [self::TARGET_UNKNOWN, self::TARGET_FOLLOWER, self::TARGET_ANSWER, self::TARGET_GLOBAL]))) {
 310                                 $reception_types[$uid] = self::TARGET_BCC;
 311                         }
 312                 } else {
 313                         // We possibly need some user to fetch private content,
 314                         // so we fetch the first out ot the list.
 315                         $uid = self::getFirstUserFromReceivers($receivers);
 316                 }
 317
 318                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 319                 if (empty($object_id)) {
 320                         Logger::log('No object found', Logger::DEBUG);
 321                         return [];
 322                 }
 323
 324                 if (!is_string($object_id)) {
 325                         Logger::info('Invalid object id', ['object' => $object_id]);
 326                         return [];
 327                 }
 328
 329                 $object_type = self::fetchObjectType($activity, $object_id, $uid);
 330
 331                 // Fetch the content only on activities where this matters
 332                 if (in_array($type, ['as:Create', 'as:Update', 'as:Announce'])) {
 333                         // Always fetch on "Announce"
 334                         $object_data = self::fetchObject($object_id, $activity['as:object'], $trust_source && ($type != 'as:Announce'), $uid);
 335                         if (empty($object_data)) {
 336                                 Logger::log("Object data couldn't be processed", Logger::DEBUG);
 337                                 return [];
 338                         }
 339
 340                         $object_data['object_id'] = $object_id;
 341
 342                         if ($type == 'as:Announce') {
 343                                 $object_data['push'] = false;
 344                         } else {
 345                                 $object_data['push'] = $push;
 346                         }
 347
 348                         // Test if it is an answer to a mail
 349                         if (DBA::exists('mail', ['uri' => $object_data['reply-to-id']])) {
 350                                 $object_data['directmessage'] = true;
 351                         } else {
 352                                 $object_data['directmessage'] = JsonLD::fetchElement($activity, 'litepub:directMessage');
 353                         }
 354                 } elseif (in_array($type, array_merge(self::ACTIVITY_TYPES, ['as:Follow'])) && in_array($object_type, self::CONTENT_TYPES)) {
 355                         // Create a mostly empty array out of the activity data (instead of the object).
 356                         // This way we later don't have to check for the existence of ech individual array element.
 357                         $object_data = self::processObject($activity);
 358                         $object_data['name'] = $type;
 359                         $object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 360                         $object_data['object_id'] = $object_id;
 361                         $object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
 362                         $object_data['push'] = $push;
 363                 } elseif (in_array($type, ['as:Add'])) {
 364                         $object_data = [];
 365                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 366                         $object_data['target_id'] = JsonLD::fetchElement($activity, 'as:target', '@id');
 367                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 368                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 369                         $object_data['object_content'] = JsonLD::fetchElement($activity['as:object'], 'as:content', '@type');
 370                         $object_data['push'] = $push;
 371                 } else {
 372                         $object_data = [];
 373                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 374                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 375                         $object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor', '@id');
 376                         $object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
 377                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 378                         $object_data['push'] = $push;
 379
 380                         // An Undo is done on the object of an object, so we need that type as well
 381                         if (($type == 'as:Undo') && !empty($object_data['object_object'])) {
 382                                 $object_data['object_object_type'] = self::fetchObjectType([], $object_data['object_object'], $uid);
 383                         }
 384                 }
 385
 386                 $object_data = self::addActivityFields($object_data, $activity);
 387
 388                 if (empty($object_data['object_type'])) {
 389                         $object_data['object_type'] = $object_type;
 390                 }
 391
 392                 $object_data['type'] = $type;
 393                 $object_data['actor'] = $actor;
 394                 $object_data['item_receiver'] = $receivers;
 395                 $object_data['receiver'] = array_replace($object_data['receiver'] ?? [], $receivers);
 396                 $object_data['reception_type'] = array_replace($object_data['reception_type'] ?? [], $reception_types);
 397
 398                 $author = $object_data['author'] ?? $actor;
 399                 if (!empty($author) && !empty($object_data['id'])) {
 400                         $author_host = parse_url($author, PHP_URL_HOST);
 401                         $id_host = parse_url($object_data['id'], PHP_URL_HOST);
 402                         if ($author_host == $id_host) {
 403                                 Logger::info('Valid hosts', ['type' => $type, 'host' => $id_host]);
 404                         } else {
 405                                 Logger::notice('Differing hosts on author and id', ['type' => $type, 'author' => $author_host, 'id' => $id_host]);
 406                                 $trust_source = false;
 407                         }
 408                 }
 409
 410                 Logger::log('Processing ' . $object_data['type'] . ' ' . $object_data['object_type'] . ' ' . $object_data['id'], Logger::DEBUG);
 411
 412                 return $object_data;
 413         }
 414
 415         /**
 416          * Fetches the first user id from the receiver array
 417          *
 418          * @param array $receivers Array with receivers
 419          * @return integer user id;
 420          */
 421         public static function getFirstUserFromReceivers($receivers)
 422         {
 423                 foreach ($receivers as $receiver) {
 424                         if (!empty($receiver)) {
 425                                 return $receiver;
 426                         }
 427                 }
 428                 return 0;
 429         }
 430
 431         /**
 432          * Processes the activity object
 433          *
 434          * @param array   $activity     Array with activity data
 435          * @param string  $body
 436          * @param integer $uid          User ID
 437          * @param boolean $trust_source Do we trust the source?
 438          * @param boolean $push         Message had been pushed to our system
 439          * @throws \Exception
 440          */
 441         public static function processActivity($activity, string $body = '', int $uid = null, bool $trust_source = false, bool $push = false, array $signer = [])
 442         {
 443                 $type = JsonLD::fetchElement($activity, '@type');
 444                 if (!$type) {
 445                         Logger::info('Empty type', ['activity' => $activity]);
 446                         return;
 447                 }
 448
 449                 if (!JsonLD::fetchElement($activity, 'as:object', '@id')) {
 450                         Logger::info('Empty object', ['activity' => $activity]);
 451                         return;
 452                 }
 453
 454                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 455                 if (empty($actor)) {
 456                         Logger::info('Empty actor', ['activity' => $activity]);
 457                         return;
 458                 }
 459
 460                 if (is_array($activity['as:object'])) {
 461                         $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
 462                 } else {
 463                         $attributed_to = '';
 464                 }
 465
 466                 // Test the provided signatures against the actor and "attributedTo"
 467                 if ($trust_source) {
 468                         if (!empty($attributed_to) && !empty($actor)) {
 469                                 $trust_source = (in_array($actor, $signer) && in_array($attributed_to, $signer));
 470                         } else {
 471                                 $trust_source = in_array($actor, $signer);
 472                         }
 473                 }
 474
 475                 // $trust_source is called by reference and is set to true if the content was retrieved successfully
 476                 $object_data = self::prepareObjectData($activity, $uid, $push, $trust_source);
 477                 if (empty($object_data)) {
 478                         Logger::info('No object data found', ['activity' => $activity]);
 479                         return;
 480                 }
 481
 482                 if (!$trust_source) {
 483                         Logger::info('Activity trust could not be achieved.',  ['id' => $object_data['object_id'], 'type' => $type, 'signer' => $signer, 'actor' => $actor, 'attributedTo' => $attributed_to]);
 484                         return;
 485                 }
 486
 487                 if (!empty($body) && empty($object_data['raw'])) {
 488                         $object_data['raw'] = $body;
 489                 }
 490
 491                 // Internal flag for thread completion. See Processor.php
 492                 if (!empty($activity['thread-completion'])) {
 493                         $object_data['thread-completion'] = $activity['thread-completion'];
 494                 }
 495
 496                 // Internal flag for posts that arrived via relay
 497                 if (!empty($activity['from-relay'])) {
 498                         $object_data['from-relay'] = $activity['from-relay'];
 499                 }
 500
 501                 switch ($type) {
 502                         case 'as:Create':
 503                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 504                                         $item = ActivityPub\Processor::createItem($object_data);
 505                                         ActivityPub\Processor::postItem($object_data, $item);
 506                                 }
 507                                 break;
 508
 509                         case 'as:Add':
 510                                 if ($object_data['object_type'] == 'as:tag') {
 511                                         ActivityPub\Processor::addTag($object_data);
 512                                 }
 513                                 break;
 514
 515                         case 'as:Announce':
 516                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 517                                         $object_data['thread-completion'] = Contact::getIdForURL($actor);
 518
 519                                         $item = ActivityPub\Processor::createItem($object_data);
 520                                         if (empty($item)) {
 521                                                 return;
 522                                         }
 523
 524                                         $item['post-type'] = Item::PT_ANNOUNCEMENT;
 525                                         ActivityPub\Processor::postItem($object_data, $item);
 526
 527                                         $announce_object_data = self::processObject($activity);
 528                                         $announce_object_data['name'] = $type;
 529                                         $announce_object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 530                                         $announce_object_data['object_id'] = $object_data['object_id'];
 531                                         $announce_object_data['object_type'] = $object_data['object_type'];
 532                                         $announce_object_data['push'] = $push;
 533
 534                                         if (!empty($body)) {
 535                                                 $announce_object_data['raw'] = $body;
 536                                         }
 537
 538                                         ActivityPub\Processor::createActivity($announce_object_data, Activity::ANNOUNCE);
 539                                 }
 540                                 break;
 541
 542                         case 'as:Like':
 543                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 544                                         ActivityPub\Processor::createActivity($object_data, Activity::LIKE);
 545                                 }
 546                                 break;
 547
 548                         case 'as:Dislike':
 549                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 550                                         ActivityPub\Processor::createActivity($object_data, Activity::DISLIKE);
 551                                 }
 552                                 break;
 553
 554                         case 'as:TentativeAccept':
 555                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 556                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDMAYBE);
 557                                 }
 558                                 break;
 559
 560                         case 'as:Update':
 561                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 562                                         ActivityPub\Processor::updateItem($object_data);
 563                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 564                                         ActivityPub\Processor::updatePerson($object_data);
 565                                 }
 566                                 break;
 567
 568                         case 'as:Delete':
 569                                 if ($object_data['object_type'] == 'as:Tombstone') {
 570                                         ActivityPub\Processor::deleteItem($object_data);
 571                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 572                                         ActivityPub\Processor::deletePerson($object_data);
 573                                 }
 574                                 break;
 575
 576                         case 'as:Follow':
 577                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 578                                         ActivityPub\Processor::followUser($object_data);
 579                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 580                                         $object_data['reply-to-id'] = $object_data['object_id'];
 581                                         ActivityPub\Processor::createActivity($object_data, Activity::FOLLOW);
 582                                 }
 583                                 break;
 584
 585                         case 'as:Accept':
 586                                 if ($object_data['object_type'] == 'as:Follow') {
 587                                         ActivityPub\Processor::acceptFollowUser($object_data);
 588                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 589                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTEND);
 590                                 }
 591                                 break;
 592
 593                         case 'as:Reject':
 594                                 if ($object_data['object_type'] == 'as:Follow') {
 595                                         ActivityPub\Processor::rejectFollowUser($object_data);
 596                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 597                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDNO);
 598                                 }
 599                                 break;
 600
 601                         case 'as:Undo':
 602                                 if (($object_data['object_type'] == 'as:Follow') &&
 603                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 604                                         ActivityPub\Processor::undoFollowUser($object_data);
 605                                 } elseif (($object_data['object_type'] == 'as:Accept') &&
 606                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 607                                         ActivityPub\Processor::rejectFollowUser($object_data);
 608                                 } elseif (in_array($object_data['object_type'], self::ACTIVITY_TYPES) &&
 609                                         in_array($object_data['object_object_type'], self::CONTENT_TYPES)) {
 610                                         ActivityPub\Processor::undoActivity($object_data);
 611                                 }
 612                                 break;
 613
 614                         default:
 615                                 Logger::log('Unknown activity: ' . $type . ' ' . $object_data['object_type'], Logger::DEBUG);
 616                                 break;
 617                 }
 618         }
 619
 620         /**
 621          * Fetch the receiver list from an activity array
 622          *
 623          * @param array   $activity
 624          * @param string  $actor
 625          * @param array   $tags
 626          * @param boolean $fetch_unlisted
 627          *
 628          * @return array with receivers (user id)
 629          * @throws \Exception
 630          */
 631         private static function getReceivers($activity, $actor, $tags = [], $fetch_unlisted = false)
 632         {
 633                 $reply = $receivers = [];
 634
 635                 // When it is an answer, we inherite the receivers from the parent
 636                 $replyto = JsonLD::fetchElement($activity, 'as:inReplyTo', '@id');
 637                 if (!empty($replyto)) {
 638                         $reply = [$replyto];
 639
 640                         // Fix possibly wrong item URI (could be an answer to a plink uri)
 641                         $fixedReplyTo = Item::getURIByLink($replyto);
 642                         if (!empty($fixedReplyTo)) {
 643                                 $reply[] = $fixedReplyTo;
 644                         }
 645                 }
 646
 647                 // Fetch all posts that refer to the object id
 648                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 649                 if (!empty($object_id)) {
 650                         $reply[] = $object_id;
 651                 }
 652
 653                 if (!empty($reply)) {
 654                         $parents = Post::select(['uid'], ['uri' => $reply]);
 655                         while ($parent = Post::fetch($parents)) {
 656                                 $receivers[$parent['uid']] = ['uid' => $parent['uid'], 'type' => self::TARGET_ANSWER];
 657                         }
 658                         DBA::close($parents);
 659                 }
 660
 661                 if (!empty($actor)) {
 662                         $profile = APContact::getByURL($actor);
 663                         $followers = $profile['followers'] ?? '';
 664
 665                         Logger::log('Actor: ' . $actor . ' - Followers: ' . $followers, Logger::DEBUG);
 666                 } else {
 667                         Logger::info('Empty actor', ['activity' => $activity]);
 668                         $followers = '';
 669                 }
 670
 671                 // We have to prevent false follower assumptions upon thread completions
 672                 $follower_target = empty($activity['thread-completion']) ? self::TARGET_FOLLOWER : self::TARGET_UNKNOWN;
 673
 674                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
 675                         $receiver_list = JsonLD::fetchElementArray($activity, $element, '@id');
 676                         if (empty($receiver_list)) {
 677                                 continue;
 678                         }
 679
 680                         foreach ($receiver_list as $receiver) {
 681                                 if ($receiver == self::PUBLIC_COLLECTION) {
 682                                         $receivers[0] = ['uid' => 0, 'type' => self::TARGET_GLOBAL];
 683                                 }
 684
 685                                 // Add receiver "-1" for unlisted posts
 686                                 if ($fetch_unlisted && ($receiver == self::PUBLIC_COLLECTION) && ($element == 'as:cc')) {
 687                                         $receivers[-1] = ['uid' => -1, 'type' => self::TARGET_GLOBAL];
 688                                 }
 689
 690                                 // Fetch the receivers for the public and the followers collection
 691                                 if (in_array($receiver, [$followers, self::PUBLIC_COLLECTION]) && !empty($actor)) {
 692                                         $receivers = self::getReceiverForActor($actor, $tags, $receivers, $follower_target);
 693                                         continue;
 694                                 }
 695
 696                                 // Fetching all directly addressed receivers
 697                                 $condition = ['self' => true, 'nurl' => Strings::normaliseLink($receiver)];
 698                                 $contact = DBA::selectFirst('contact', ['uid', 'contact-type'], $condition);
 699                                 if (!DBA::isResult($contact)) {
 700                                         continue;
 701                                 }
 702
 703                                 // Check if the potential receiver is following the actor
 704                                 // Exception: The receiver is targetted via "to" or this is a comment
 705                                 if ((($element != 'as:to') && empty($replyto)) || ($contact['contact-type'] == Contact::TYPE_COMMUNITY)) {
 706                                         $networks = Protocol::FEDERATED;
 707                                         $condition = ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
 708                                                 'network' => $networks, 'archive' => false, 'pending' => false, 'uid' => $contact['uid']];
 709
 710                                         // Forum posts are only accepted from forum contacts
 711                                         if ($contact['contact-type'] == Contact::TYPE_COMMUNITY) {
 712                                                 $condition['rel'] = [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER];
 713                                         }
 714
 715                                         if (!DBA::exists('contact', $condition)) {
 716                                                 continue;
 717                                         }
 718                                 }
 719
 720                                 $type = $receivers[$contact['uid']]['type'] ?? self::TARGET_UNKNOWN;
 721                                 if (in_array($type, [self::TARGET_UNKNOWN, self::TARGET_FOLLOWER, self::TARGET_ANSWER, self::TARGET_GLOBAL])) {
 722                                         switch ($element) {
 723                                                 case 'as:to':
 724                                                         $type = self::TARGET_TO;
 725                                                         break;
 726                                                 case 'as:cc':
 727                                                         $type = self::TARGET_CC;
 728                                                         break;
 729                                                 case 'as:bto':
 730                                                         $type = self::TARGET_BTO;
 731                                                         break;
 732                                                 case 'as:bcc':
 733                                                         $type = self::TARGET_BCC;
 734                                                         break;
 735                                         }
 736
 737                                         $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $type];
 738                                 }
 739                         }
 740                 }
 741
 742                 self::switchContacts($receivers, $actor);
 743
 744                 return $receivers;
 745         }
 746
 747         /**
 748          * Fetch the receiver list of a given actor
 749          *
 750          * @param string  $actor
 751          * @param array   $tags
 752          * @param array   $receivers
 753          * @param integer $target_type
 754          *
 755          * @return array with receivers (user id)
 756          * @throws \Exception
 757          */
 758         private static function getReceiverForActor($actor, $tags, $receivers, $target_type)
 759         {
 760                 $basecondition = ['rel' => [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER],
 761                         'network' => Protocol::FEDERATED, 'archive' => false, 'pending' => false];
 762
 763                 $condition = DBA::mergeConditions($basecondition, ["`nurl` = ? AND `uid` != ?", Strings::normaliseLink($actor), 0]);
 764                 $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
 765                 while ($contact = DBA::fetch($contacts)) {
 766                         if (empty($receivers[$contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
 767                                 $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $target_type];
 768                         }
 769                 }
 770                 DBA::close($contacts);
 771
 772                 // The queries are split because of performance issues
 773                 $condition = DBA::mergeConditions($basecondition, ["`alias` IN (?, ?) AND `uid` != ?", Strings::normaliseLink($actor), $actor, 0]);
 774                 $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
 775                 while ($contact = DBA::fetch($contacts)) {
 776                         if (empty($receivers[$contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
 777                                 $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $target_type];
 778                         }
 779                 }
 780                 DBA::close($contacts);
 781                 return $receivers;
 782         }
 783
 784         /**
 785          * Tests if the contact is a valid receiver for this actor
 786          *
 787          * @param array  $contact
 788          * @param string $actor
 789          * @param array  $tags
 790          *
 791          * @return bool with receivers (user id)
 792          * @throws \Exception
 793          */
 794         private static function isValidReceiverForActor($contact, $tags)
 795         {
 796                 // Are we following the contact? Then this is a valid receiver
 797                 if (in_array($contact['rel'], [Contact::SHARING, Contact::FRIEND])) {
 798                         return true;
 799                 }
 800
 801                 // When the possible receiver isn't a community, then it is no valid receiver
 802                 $owner = User::getOwnerDataById($contact['uid']);
 803                 if (empty($owner) || ($owner['contact-type'] != Contact::TYPE_COMMUNITY)) {
 804                         return false;
 805                 }
 806
 807                 // Is the community account tagged?
 808                 foreach ($tags as $tag) {
 809                         if ($tag['type'] != 'Mention') {
 810                                 continue;
 811                         }
 812
 813                         if (Strings::compareLink($tag['href'], $owner['url'])) {
 814                                 return true;
 815                         }
 816                 }
 817
 818                 return false;
 819         }
 820
 821         /**
 822          * Switches existing contacts to ActivityPub
 823          *
 824          * @param integer $cid Contact ID
 825          * @param integer $uid User ID
 826          * @param string  $url Profile URL
 827          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 828          * @throws \ImagickException
 829          */
 830         public static function switchContact($cid, $uid, $url)
 831         {
 832                 if (DBA::exists('contact', ['id' => $cid, 'network' => Protocol::ACTIVITYPUB])) {
 833                         Logger::info('Contact is already ActivityPub', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
 834                         return;
 835                 }
 836
 837                 if (Contact::updateFromProbe($cid)) {
 838                         Logger::info('Update was successful', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
 839                 }
 840
 841                 // Send a new follow request to be sure that the connection still exists
 842                 if (($uid != 0) && DBA::exists('contact', ['id' => $cid, 'rel' => [Contact::SHARING, Contact::FRIEND], 'network' => Protocol::ACTIVITYPUB])) {
 843                         Logger::info('Contact had been switched to ActivityPub. Sending a new follow request.', ['uid' => $uid, 'url' => $url]);
 844                         ActivityPub\Transmitter::sendActivity('Follow', $url, $uid);
 845                 }
 846         }
 847
 848         /**
 849          *
 850          *
 851          * @param $receivers
 852          * @param $actor
 853          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 854          * @throws \ImagickException
 855          */
 856         private static function switchContacts($receivers, $actor)
 857         {
 858                 if (empty($actor)) {
 859                         return;
 860                 }
 861
 862                 foreach ($receivers as $receiver) {
 863                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver['uid'], 'network' => Protocol::OSTATUS, 'nurl' => Strings::normaliseLink($actor)]);
 864                         if (DBA::isResult($contact)) {
 865                                 self::switchContact($contact['id'], $receiver['uid'], $actor);
 866                         }
 867
 868                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver['uid'], 'network' => Protocol::OSTATUS, 'alias' => [Strings::normaliseLink($actor), $actor]]);
 869                         if (DBA::isResult($contact)) {
 870                                 self::switchContact($contact['id'], $receiver['uid'], $actor);
 871                         }
 872                 }
 873         }
 874
 875         /**
 876          *
 877          *
 878          * @param       $object_data
 879          * @param array $activity
 880          *
 881          * @return mixed
 882          */
 883         private static function addActivityFields($object_data, $activity)
 884         {
 885                 if (!empty($activity['published']) && empty($object_data['published'])) {
 886                         $object_data['published'] = JsonLD::fetchElement($activity, 'as:published', '@value');
 887                 }
 888
 889                 if (!empty($activity['diaspora:guid']) && empty($object_data['diaspora:guid'])) {
 890                         $object_data['diaspora:guid'] = JsonLD::fetchElement($activity, 'diaspora:guid', '@value');
 891                 }
 892
 893                 $object_data['service'] = JsonLD::fetchElement($activity, 'as:instrument', 'as:name', '@type', 'as:Service');
 894                 $object_data['service'] = JsonLD::fetchElement($object_data, 'service', '@value');
 895
 896                 if (!empty($object_data['object_id'])) {
 897                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
 898                         $objectId = Item::getURIByLink($object_data['object_id']);
 899                         if (!empty($objectId) && ($object_data['object_id'] != $objectId)) {
 900                                 Logger::notice('Fix wrong object-id', ['received' => $object_data['object_id'], 'correct' => $objectId]);
 901                                 $object_data['object_id'] = $objectId;
 902                         }
 903                 }
 904
 905                 return $object_data;
 906         }
 907
 908         /**
 909          * Fetches the object data from external ressources if needed
 910          *
 911          * @param string  $object_id    Object ID of the the provided object
 912          * @param array   $object       The provided object array
 913          * @param boolean $trust_source Do we trust the provided object?
 914          * @param integer $uid          User ID for the signature that we use to fetch data
 915          *
 916          * @return array|false with trusted and valid object data
 917          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 918          * @throws \ImagickException
 919          */
 920         private static function fetchObject(string $object_id, array $object = [], bool $trust_source = false, int $uid = 0)
 921         {
 922                 // By fetching the type we check if the object is complete.
 923                 $type = JsonLD::fetchElement($object, '@type');
 924
 925                 if (!$trust_source || empty($type)) {
 926                         $data = ActivityPub::fetchContent($object_id, $uid);
 927                         if (!empty($data)) {
 928                                 $object = JsonLD::compact($data);
 929                                 Logger::log('Fetched content for ' . $object_id, Logger::DEBUG);
 930                         } else {
 931                                 Logger::log('Empty content for ' . $object_id . ', check if content is available locally.', Logger::DEBUG);
 932
 933                                 $item = Post::selectFirst([], ['uri' => $object_id]);
 934                                 if (!DBA::isResult($item)) {
 935                                         Logger::log('Object with url ' . $object_id . ' was not found locally.', Logger::DEBUG);
 936                                         return false;
 937                                 }
 938                                 Logger::log('Using already stored item for url ' . $object_id, Logger::DEBUG);
 939                                 $data = ActivityPub\Transmitter::createNote($item);
 940                                 $object = JsonLD::compact($data);
 941                         }
 942
 943                         $id = JsonLD::fetchElement($object, '@id');
 944                         if (empty($id)) {
 945                                 Logger::info('Empty id');
 946                                 return false;
 947                         }
 948
 949                         if ($id != $object_id) {
 950                                 Logger::info('Fetched id differs from provided id', ['provided' => $object_id, 'fetched' => $id]);
 951                                 return false;
 952                         }
 953                 } else {
 954                         Logger::log('Using original object for url ' . $object_id, Logger::DEBUG);
 955                 }
 956
 957                 $type = JsonLD::fetchElement($object, '@type');
 958                 if (empty($type)) {
 959                         Logger::info('Empty type');
 960                         return false;
 961                 }
 962
 963                 // We currently don't handle 'pt:CacheFile', but with this step we avoid logging
 964                 if (in_array($type, self::CONTENT_TYPES) || ($type == 'pt:CacheFile')) {
 965                         $object_data = self::processObject($object);
 966
 967                         if (!empty($data)) {
 968                                 $object_data['raw'] = json_encode($data);
 969                         }
 970                         return $object_data;
 971                 }
 972
 973                 if ($type == 'as:Announce') {
 974                         $object_id = JsonLD::fetchElement($object, 'object', '@id');
 975                         if (empty($object_id) || !is_string($object_id)) {
 976                                 return false;
 977                         }
 978                         return self::fetchObject($object_id, [], false, $uid);
 979                 }
 980
 981                 Logger::log('Unhandled object type: ' . $type, Logger::DEBUG);
 982                 return false;
 983         }
 984
 985         /**
 986          * Convert tags from JSON-LD format into a simplified format
 987          *
 988          * @param array $tags Tags in JSON-LD format
 989          *
 990          * @return array with tags in a simplified format
 991          */
 992         public static function processTags(array $tags)
 993         {
 994                 $taglist = [];
 995
 996                 foreach ($tags as $tag) {
 997                         if (empty($tag)) {
 998                                 continue;
 999                         }
1000
1001                         $element = ['type' => str_replace('as:', '', JsonLD::fetchElement($tag, '@type')),
1002                                 'href' => JsonLD::fetchElement($tag, 'as:href', '@id'),
1003                                 'name' => JsonLD::fetchElement($tag, 'as:name', '@value')];
1004
1005                         if (empty($element['type'])) {
1006                                 continue;
1007                         }
1008
1009                         if (empty($element['href'])) {
1010                                 $element['href'] = $element['name'];
1011                         }
1012
1013                         $taglist[] = $element;
1014                 }
1015                 return $taglist;
1016         }
1017
1018         /**
1019          * Convert emojis from JSON-LD format into a simplified format
1020          *
1021          * @param array $emojis
1022          * @return array with emojis in a simplified format
1023          */
1024         private static function processEmojis(array $emojis)
1025         {
1026                 $emojilist = [];
1027
1028                 foreach ($emojis as $emoji) {
1029                         if (empty($emoji) || (JsonLD::fetchElement($emoji, '@type') != 'toot:Emoji') || empty($emoji['as:icon'])) {
1030                                 continue;
1031                         }
1032
1033                         $url = JsonLD::fetchElement($emoji['as:icon'], 'as:url', '@id');
1034                         $element = ['name' => JsonLD::fetchElement($emoji, 'as:name', '@value'),
1035                                 'href' => $url];
1036
1037                         $emojilist[] = $element;
1038                 }
1039
1040                 return $emojilist;
1041         }
1042
1043         /**
1044          * Convert attachments from JSON-LD format into a simplified format
1045          *
1046          * @param array $attachments Attachments in JSON-LD format
1047          *
1048          * @return array Attachments in a simplified format
1049          */
1050         private static function processAttachments(array $attachments)
1051         {
1052                 $attachlist = [];
1053
1054                 // Removes empty values
1055                 $attachments = array_filter($attachments);
1056
1057                 foreach ($attachments as $attachment) {
1058                         switch (JsonLD::fetchElement($attachment, '@type')) {
1059                                 case 'as:Page':
1060                                         $pageUrl = null;
1061                                         $pageImage = null;
1062
1063                                         $urls = JsonLD::fetchElementArray($attachment, 'as:url');
1064                                         foreach ($urls as $url) {
1065                                                 // Single scalar URL case
1066                                                 if (is_string($url)) {
1067                                                         $pageUrl = $url;
1068                                                         continue;
1069                                                 }
1070
1071                                                 $href = JsonLD::fetchElement($url, 'as:href', '@id');
1072                                                 $mediaType = JsonLD::fetchElement($url, 'as:mediaType', '@value');
1073                                                 if (Strings::startsWith($mediaType, 'image')) {
1074                                                         $pageImage = $href;
1075                                                 } else {
1076                                                         $pageUrl = $href;
1077                                                 }
1078                                         }
1079
1080                                         $attachlist[] = [
1081                                                 'type'  => 'link',
1082                                                 'title' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1083                                                 'desc'  => JsonLD::fetchElement($attachment, 'as:summary', '@value'),
1084                                                 'url'   => $pageUrl,
1085                                                 'image' => $pageImage,
1086                                         ];
1087                                         break;
1088                                 case 'as:Link':
1089                                         $attachlist[] = [
1090                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1091                                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType', '@value'),
1092                                                 'name' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1093                                                 'url' => JsonLD::fetchElement($attachment, 'as:href', '@id')
1094                                         ];
1095                                         break;
1096                                 case 'as:Image':
1097                                         $mediaType = JsonLD::fetchElement($attachment, 'as:mediaType', '@value');
1098                                         $imageFullUrl = JsonLD::fetchElement($attachment, 'as:url', '@id');
1099                                         $imagePreviewUrl = null;
1100                                         // Multiple URLs?
1101                                         if (!$imageFullUrl && ($urls = JsonLD::fetchElementArray($attachment, 'as:url'))) {
1102                                                 $imageVariants = [];
1103                                                 $previewVariants = [];
1104                                                 foreach ($urls as $url) {
1105                                                         // Scalar URL, no discrimination possible
1106                                                         if (is_string($url)) {
1107                                                                 $imageFullUrl = $url;
1108                                                                 continue;
1109                                                         }
1110
1111                                                         // Not sure what to do with a different Link media type than the base Image, we skip
1112                                                         if ($mediaType != JsonLD::fetchElement($url, 'as:mediaType', '@value')) {
1113                                                                 continue;
1114                                                         }
1115
1116                                                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1117
1118                                                         // Default URL choice if no discriminating width is provided
1119                                                         $imageFullUrl = $href ?? $imageFullUrl;
1120
1121                                                         $width = intval(JsonLD::fetchElement($url, 'as:width', '@value') ?? 1);
1122
1123                                                         if ($href && $width) {
1124                                                                 $imageVariants[$width] = $href;
1125                                                                 // 632 is the ideal width for full screen frio posts, we compute the absolute distance to it
1126                                                                 $previewVariants[abs(632 - $width)] = $href;
1127                                                         }
1128                                                 }
1129
1130                                                 if ($imageVariants) {
1131                                                         // Taking the maximum size image
1132                                                         ksort($imageVariants);
1133                                                         $imageFullUrl = array_pop($imageVariants);
1134
1135                                                         // Taking the minimum number distance to the target distance
1136                                                         ksort($previewVariants);
1137                                                         $imagePreviewUrl = array_shift($previewVariants);
1138                                                 }
1139
1140                                                 unset($imageVariants);
1141                                                 unset($previewVariants);
1142                                         }
1143
1144                                         $attachlist[] = [
1145                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1146                                                 'mediaType' => $mediaType,
1147                                                 'name'  => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1148                                                 'url'   => $imageFullUrl,
1149                                                 'image' => $imagePreviewUrl !== $imageFullUrl ? $imagePreviewUrl : null,
1150                                         ];
1151                                         break;
1152                                 default:
1153                                         $attachlist[] = [
1154                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1155                                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType', '@value'),
1156                                                 'name' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1157                                                 'url' => JsonLD::fetchElement($attachment, 'as:url', '@id')
1158                                         ];
1159                         }
1160                 }
1161
1162                 return $attachlist;
1163         }
1164
1165         /**
1166          * Fetch the original source or content with the "language" Markdown or HTML
1167          *
1168          * @param array $object
1169          * @param array $object_data
1170          *
1171          * @return array
1172          * @throws \Exception
1173          */
1174         private static function getSource($object, $object_data)
1175         {
1176                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/bbcode');
1177                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1178                 if (!empty($object_data['source'])) {
1179                         return $object_data;
1180                 }
1181
1182                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/markdown');
1183                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1184                 if (!empty($object_data['source'])) {
1185                         $object_data['source'] = Markdown::toBBCode($object_data['source']);
1186                         return $object_data;
1187                 }
1188
1189                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/html');
1190                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1191                 if (!empty($object_data['source'])) {
1192                         $object_data['source'] = HTML::toBBCode($object_data['source']);
1193                         return $object_data;
1194                 }
1195
1196                 return $object_data;
1197         }
1198
1199         /**
1200          * Check if the "as:url" element is an array with multiple links
1201          * This is the case with audio and video posts.
1202          * Then the links are added as attachments
1203          *
1204          * @param array $object      The raw object
1205          * @param array $object_data The parsed object data for later processing
1206          * @return array the object data
1207          */
1208         private static function processAttachmentUrls(array $object, array $object_data) {
1209                 // Check if this is some url with multiple links
1210                 if (empty($object['as:url'])) {
1211                         return $object_data;
1212                 }
1213
1214                 $urls = $object['as:url'];
1215                 $keys = array_keys($urls);
1216                 if (!is_numeric(array_pop($keys))) {
1217                         return $object_data;
1218                 }
1219
1220                 $attachments = [];
1221
1222                 foreach ($urls as $url) {
1223                         if (empty($url['@type']) || ($url['@type'] != 'as:Link')) {
1224                                 continue;
1225                         }
1226
1227                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1228                         if (empty($href)) {
1229                                 continue;
1230                         }
1231
1232                         $mediatype = JsonLD::fetchElement($url, 'as:mediaType');
1233                         if (empty($mediatype)) {
1234                                 continue;
1235                         }
1236
1237                         if ($mediatype == 'text/html') {
1238                                 $object_data['alternate-url'] = $href;
1239                         }
1240
1241                         $filetype = strtolower(substr($mediatype, 0, strpos($mediatype, '/')));
1242
1243                         if ($filetype == 'audio') {
1244                                 $attachments[$filetype] = ['type' => $mediatype, 'url' => $href, 'height' => null, 'size' => null];
1245                         } elseif ($filetype == 'video') {
1246                                 $height = (int)JsonLD::fetchElement($url, 'as:height', '@value');
1247                                 $size = (int)JsonLD::fetchElement($url, 'pt:size', '@value');
1248
1249                                 // We save bandwidth by using a moderate height (alt least 480 pixel height)
1250                                 // Peertube normally uses these heights: 240, 360, 480, 720, 1080
1251                                 if (!empty($attachments[$filetype]['height']) &&
1252                                         ($height > $attachments[$filetype]['height']) && ($attachments[$filetype]['height'] >= 480)) {
1253                                         continue;
1254                                 }
1255
1256                                 $attachments[$filetype] = ['type' => $mediatype, 'url' => $href, 'height' => $height, 'size' => $size];
1257                         } elseif (in_array($mediatype, ['application/x-bittorrent', 'application/x-bittorrent;x-scheme-handler/magnet'])) {
1258                                 $height = (int)JsonLD::fetchElement($url, 'as:height', '@value');
1259
1260                                 // For Torrent links we always store the highest resolution
1261                                 if (!empty($attachments[$mediatype]['height']) && ($height < $attachments[$mediatype]['height'])) {
1262                                         continue;
1263                                 }
1264
1265                                 $attachments[$mediatype] = ['type' => $mediatype, 'url' => $href, 'height' => $height, 'size' => null];
1266                         }
1267                 }
1268
1269                 foreach ($attachments as $type => $attachment) {
1270                         $object_data['attachments'][] = ['type' => $type,
1271                                 'mediaType' => $attachment['type'],
1272                                 'height' => $attachment['height'],
1273                                 'size' => $attachment['size'],
1274                                 'name' => '',
1275                                 'url' => $attachment['url']];
1276                 }
1277                 return $object_data;
1278         }
1279
1280         /**
1281          * Fetches data from the object part of an activity
1282          *
1283          * @param array $object
1284          *
1285          * @return array
1286          * @throws \Exception
1287          */
1288         private static function processObject($object)
1289         {
1290                 if (!JsonLD::fetchElement($object, '@id')) {
1291                         return false;
1292                 }
1293
1294                 $object_data = [];
1295                 $object_data['object_type'] = JsonLD::fetchElement($object, '@type');
1296                 $object_data['id'] = JsonLD::fetchElement($object, '@id');
1297                 $object_data['reply-to-id'] = JsonLD::fetchElement($object, 'as:inReplyTo', '@id');
1298
1299                 // An empty "id" field is translated to "./" by the compactor, so we have to check for this content
1300                 if (empty($object_data['reply-to-id']) || ($object_data['reply-to-id'] == './')) {
1301                         $object_data['reply-to-id'] = $object_data['id'];
1302                 } else {
1303                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
1304                         $replyToId = Item::getURIByLink($object_data['reply-to-id']);
1305                         if (!empty($replyToId) && ($object_data['reply-to-id'] != $replyToId)) {
1306                                 Logger::notice('Fix wrong reply-to', ['received' => $object_data['reply-to-id'], 'correct' => $replyToId]);
1307                                 $object_data['reply-to-id'] = $replyToId;
1308                         }
1309                 }
1310
1311                 $object_data['published'] = JsonLD::fetchElement($object, 'as:published', '@value');
1312                 $object_data['updated'] = JsonLD::fetchElement($object, 'as:updated', '@value');
1313
1314                 if (empty($object_data['updated'])) {
1315                         $object_data['updated'] = $object_data['published'];
1316                 }
1317
1318                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
1319                         $object_data['published'] = $object_data['updated'];
1320                 }
1321
1322                 $actor = JsonLD::fetchElement($object, 'as:attributedTo', '@id');
1323                 if (empty($actor)) {
1324                         $actor = JsonLD::fetchElement($object, 'as:actor', '@id');
1325                 }
1326
1327                 $location = JsonLD::fetchElement($object, 'as:location', 'as:name', '@type', 'as:Place');
1328                 $location = JsonLD::fetchElement($location, 'location', '@value');
1329                 if ($location) {
1330                         // Some AP software allow formatted text in post location, so we run all the text converters we have to boil
1331                         // down to HTML and then finally format to plaintext.
1332                         $location = Markdown::convert($location);
1333                         $location = BBCode::convert($location);
1334                         $location = HTML::toPlaintext($location);
1335                 }
1336
1337                 $object_data['sc:identifier'] = JsonLD::fetchElement($object, 'sc:identifier', '@value');
1338                 $object_data['diaspora:guid'] = JsonLD::fetchElement($object, 'diaspora:guid', '@value');
1339                 $object_data['diaspora:comment'] = JsonLD::fetchElement($object, 'diaspora:comment', '@value');
1340                 $object_data['diaspora:like'] = JsonLD::fetchElement($object, 'diaspora:like', '@value');
1341                 $object_data['actor'] = $object_data['author'] = $actor;
1342                 $object_data['context'] = JsonLD::fetchElement($object, 'as:context', '@id');
1343                 $object_data['conversation'] = JsonLD::fetchElement($object, 'ostatus:conversation', '@id');
1344                 $object_data['sensitive'] = JsonLD::fetchElement($object, 'as:sensitive');
1345                 $object_data['name'] = JsonLD::fetchElement($object, 'as:name', '@value');
1346                 $object_data['summary'] = JsonLD::fetchElement($object, 'as:summary', '@value');
1347                 $object_data['content'] = JsonLD::fetchElement($object, 'as:content', '@value');
1348                 $object_data = self::getSource($object, $object_data);
1349                 $object_data['start-time'] = JsonLD::fetchElement($object, 'as:startTime', '@value');
1350                 $object_data['end-time'] = JsonLD::fetchElement($object, 'as:endTime', '@value');
1351                 $object_data['location'] = $location;
1352                 $object_data['latitude'] = JsonLD::fetchElement($object, 'as:location', 'as:latitude', '@type', 'as:Place');
1353                 $object_data['latitude'] = JsonLD::fetchElement($object_data, 'latitude', '@value');
1354                 $object_data['longitude'] = JsonLD::fetchElement($object, 'as:location', 'as:longitude', '@type', 'as:Place');
1355                 $object_data['longitude'] = JsonLD::fetchElement($object_data, 'longitude', '@value');
1356                 $object_data['attachments'] = self::processAttachments(JsonLD::fetchElementArray($object, 'as:attachment') ?? []);
1357                 $object_data['tags'] = self::processTags(JsonLD::fetchElementArray($object, 'as:tag') ?? []);
1358                 $object_data['emojis'] = self::processEmojis(JsonLD::fetchElementArray($object, 'as:tag', null, '@type', 'toot:Emoji') ?? []);
1359                 $object_data['generator'] = JsonLD::fetchElement($object, 'as:generator', 'as:name', '@type', 'as:Application');
1360                 $object_data['generator'] = JsonLD::fetchElement($object_data, 'generator', '@value');
1361                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'as:url', '@id');
1362
1363                 // Special treatment for Hubzilla links
1364                 if (is_array($object_data['alternate-url'])) {
1365                         $object_data['alternate-url'] = JsonLD::fetchElement($object_data['alternate-url'], 'as:href', '@id');
1366
1367                         if (!is_string($object_data['alternate-url'])) {
1368                                 $object_data['alternate-url'] = JsonLD::fetchElement($object['as:url'], 'as:href', '@id');
1369                         }
1370                 }
1371
1372                 if (in_array($object_data['object_type'], ['as:Audio', 'as:Video'])) {
1373                         $object_data = self::processAttachmentUrls($object, $object_data);
1374                 }
1375
1376                 $receiverdata = self::getReceivers($object, $object_data['actor'], $object_data['tags'], true);
1377                 $receivers = $reception_types = [];
1378                 foreach ($receiverdata as $key => $data) {
1379                         $receivers[$key] = $data['uid'];
1380                         $reception_types[$data['uid']] = $data['type'] ?? 0;
1381                 }
1382
1383                 $object_data['receiver'] = $receivers;
1384                 $object_data['reception_type'] = $reception_types;
1385
1386                 $object_data['unlisted'] = in_array(-1, $object_data['receiver']);
1387                 unset($object_data['receiver'][-1]);
1388                 unset($object_data['reception_type'][-1]);
1389
1390                 // Common object data:
1391
1392                 // Unhandled
1393                 // @context, type, actor, signature, mediaType, duration, replies, icon
1394
1395                 // Also missing: (Defined in the standard, but currently unused)
1396                 // audience, preview, endTime, startTime, image
1397
1398                 // Data in Notes:
1399
1400                 // Unhandled
1401                 // contentMap, announcement_count, announcements, context_id, likes, like_count
1402                 // inReplyToStatusId, shares, quoteUrl, statusnetConversationId
1403
1404                 // Data in video:
1405
1406                 // To-Do?
1407                 // category, licence, language, commentsEnabled
1408
1409                 // Unhandled
1410                 // views, waitTranscoding, state, support, subtitleLanguage
1411                 // likes, dislikes, shares, comments
1412
1413                 return $object_data;
1414         }
1415 }