src/Protocol/ActivityPub/Receiver.php

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