src/Protocol/ActivityPub/Receiver.php

   1 <?php
   2 /**
   3  * @copyright Copyright (C) 2010-2023, the Friendica project
   4  *
   5  * @license GNU AGPL version 3 or any later version
   6  *
   7  * This program is free software: you can redistribute it and/or modify
   8  * it under the terms of the GNU Affero General Public License as
   9  * published by the Free Software Foundation, either version 3 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU Affero General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Affero General Public License
  18  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  19  *
  20  */
  21
  22 namespace Friendica\Protocol\ActivityPub;
  23
  24 use Friendica\Content\Text\BBCode;
  25 use Friendica\Database\DBA;
  26 use Friendica\Content\Text\HTML;
  27 use Friendica\Content\Text\Markdown;
  28 use Friendica\Core\Logger;
  29 use Friendica\Core\Protocol;
  30 use Friendica\Core\System;
  31 use Friendica\Core\Worker;
  32 use Friendica\Database\Database;
  33 use Friendica\DI;
  34 use Friendica\Model\Contact;
  35 use Friendica\Model\APContact;
  36 use Friendica\Model\Item;
  37 use Friendica\Model\Post;
  38 use Friendica\Model\User;
  39 use Friendica\Protocol\Activity;
  40 use Friendica\Protocol\ActivityPub;
  41 use Friendica\Util\DateTimeFormat;
  42 use Friendica\Util\HTTPSignature;
  43 use Friendica\Util\JsonLD;
  44 use Friendica\Util\LDSignature;
  45 use Friendica\Util\Network;
  46 use Friendica\Util\Strings;
  47
  48 /**
  49  * ActivityPub Receiver Protocol class
  50  *
  51  * To-Do:
  52  * @todo Undo Announce
  53  *
  54  * Check what this is meant to do:
  55  * - Add
  56  * - Block
  57  * - Flag
  58  * - Remove
  59  * - Undo Block
  60  */
  61 class Receiver
  62 {
  63         const PUBLIC_COLLECTION = 'as:Public';
  64         const ACCOUNT_TYPES = ['as:Person', 'as:Organization', 'as:Service', 'as:Group', 'as:Application'];
  65         const CONTENT_TYPES = ['as:Note', 'as:Article', 'as:Video', 'as:Image', 'as:Event', 'as:Audio', 'as:Page', 'as:Question'];
  66         const ACTIVITY_TYPES = ['as:Like', 'as:Dislike', 'as:Accept', 'as:Reject', 'as:TentativeAccept', 'as:View', 'as:Read', 'litepub:EmojiReact'];
  67
  68         const TARGET_UNKNOWN = 0;
  69         const TARGET_TO = 1;
  70         const TARGET_CC = 2;
  71         const TARGET_BTO = 3;
  72         const TARGET_BCC = 4;
  73         const TARGET_FOLLOWER = 5;
  74         const TARGET_ANSWER = 6;
  75         const TARGET_GLOBAL = 7;
  76
  77         const COMPLETION_NONE     = 0;
  78         const COMPLETION_ANNOUNCE = 1;
  79         const COMPLETION_RELAY    = 2;
  80         const COMPLETION_MANUAL   = 3;
  81         const COMPLETION_AUTO     = 4;
  82
  83         /**
  84          * Checks incoming message from the inbox
  85          *
  86          * @param string  $body Body string
  87          * @param array   $header Header lines
  88          * @param integer $uid User ID
  89          * @return void
  90          * @throws \Exception
  91          */
  92         public static function processInbox(string $body, array $header, int $uid)
  93         {
  94                 $activity = json_decode($body, true);
  95                 if (empty($activity)) {
  96                         Logger::warning('Invalid body.');
  97                         return;
  98                 }
  99
 100                 $ldactivity = JsonLD::compact($activity);
 101
 102                 $actor = JsonLD::fetchElement($ldactivity, 'as:actor', '@id') ?? '';
 103
 104                 $apcontact = APContact::getByURL($actor);
 105
 106                 if (empty($apcontact)) {
 107                         Logger::notice('Unable to retrieve AP contact for actor - message is discarded', ['actor' => $actor]);
 108                         return;
 109                 } elseif (APContact::isRelay($apcontact)) {
 110                         self::processRelayPost($ldactivity, $actor);
 111                         return;
 112                 } else {
 113                         APContact::unmarkForArchival($apcontact);
 114                 }
 115
 116                 $sig_contact = HTTPSignature::getKeyIdContact($header);
 117                 if (APContact::isRelay($sig_contact)) {
 118                         Logger::info('Message from a relay', ['url' => $sig_contact['url']]);
 119                         self::processRelayPost($ldactivity, $sig_contact['url']);
 120                         return;
 121                 }
 122
 123                 $http_signer = HTTPSignature::getSigner($body, $header);
 124                 if ($http_signer === false) {
 125                         Logger::notice('Invalid HTTP signature, message will not be trusted.', ['uid' => $uid, 'actor' => $actor, 'header' => $header, 'body' => $body]);
 126                         $signer = [];
 127                 } elseif (empty($http_signer)) {
 128                         Logger::info('Signer is a tombstone. The message will be discarded, the signer account is deleted.');
 129                         return;
 130                 } else {
 131                         Logger::info('Valid HTTP signature', ['signer' => $http_signer]);
 132                         $signer = [$http_signer];
 133                 }
 134
 135                 Logger::info('Message for user ' . $uid . ' is from actor ' . $actor);
 136
 137                 if ($http_signer === false) {
 138                         $trust_source = false;
 139                 } elseif (LDSignature::isSigned($activity)) {
 140                         $ld_signer = LDSignature::getSigner($activity);
 141                         if (empty($ld_signer)) {
 142                                 Logger::info('Invalid JSON-LD signature from ' . $actor);
 143                         } elseif ($ld_signer != $http_signer) {
 144                                 $signer[] = $ld_signer;
 145                         }
 146                         if (!empty($ld_signer && ($actor == $http_signer))) {
 147                                 Logger::info('The HTTP and the JSON-LD signature belong to ' . $ld_signer);
 148                                 $trust_source = true;
 149                         } elseif (!empty($ld_signer)) {
 150                                 Logger::info('JSON-LD signature is signed by ' . $ld_signer);
 151                                 $trust_source = true;
 152                         } elseif ($actor == $http_signer) {
 153                                 Logger::info('Bad JSON-LD signature, but HTTP signer fits the actor.');
 154                                 $trust_source = true;
 155                         } else {
 156                                 Logger::info('Invalid JSON-LD signature and the HTTP signer is different.');
 157                                 $trust_source = false;
 158                         }
 159                 } elseif ($actor == $http_signer) {
 160                         Logger::info('Trusting post without JSON-LD signature, The actor fits the HTTP signer.');
 161                         $trust_source = true;
 162                 } else {
 163                         Logger::info('No JSON-LD signature, different actor.');
 164                         $trust_source = false;
 165                 }
 166
 167                 self::processActivity($ldactivity, $body, $uid, $trust_source, true, $signer, $http_signer);
 168         }
 169
 170         /**
 171          * Process incoming posts from relays
 172          *
 173          * @param array  $activity
 174          * @param string $actor
 175          * @return void
 176          */
 177         private static function processRelayPost(array $activity, string $actor)
 178         {
 179                 $type = JsonLD::fetchElement($activity, '@type');
 180                 if (!$type) {
 181                         Logger::notice('Empty type', ['activity' => $activity, 'actor' => $actor]);
 182                         return;
 183                 }
 184
 185                 $object_type = JsonLD::fetchElement($activity, 'as:object', '@type') ?? '';
 186
 187                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 188                 if (empty($object_id)) {
 189                         Logger::notice('No object id found', ['type' => $type, 'object_type' => $object_type, 'actor' => $actor, 'activity' => $activity]);
 190                         return;
 191                 }
 192
 193                 $handle = ($type == 'as:Announce');
 194
 195                 if (!$handle && in_array($type, ['as:Create', 'as:Update'])) {
 196                         $handle = in_array($object_type, self::CONTENT_TYPES);
 197                 }
 198
 199                 if (!$handle) {
 200                         $trust_source = false;
 201                         $object_data = self::prepareObjectData($activity, 0, false, $trust_source);
 202
 203                         if (!$trust_source) {
 204                                 Logger::notice('Activity trust could not be achieved.',  ['type' => $type, 'object_type' => $object_type, 'object_id' => $object_id, 'actor' => $actor, 'activity' => $activity]);
 205                                 return;
 206                         }
 207
 208                         if (empty($object_data)) {
 209                                 Logger::notice('No object data found', ['type' => $type, 'object_type' => $object_type, 'object_id' => $object_id, 'actor' => $actor, 'activity' => $activity]);
 210                                 return;
 211                         }
 212
 213                         if (self::routeActivities($object_data, $type, true)) {
 214                                 Logger::debug('Handled activity', ['type' => $type, 'object_type' => $object_type, 'object_id' => $object_id, 'actor' => $actor]);
 215                         } else {
 216                                 Logger::info('Unhandled activity', ['type' => $type, 'object_type' => $object_type, 'object_id' => $object_id, 'actor' => $actor, 'activity' => $activity]);
 217                         }
 218                         return;
 219                 }
 220
 221                 $contact = Contact::getByURL($actor);
 222                 if (empty($contact)) {
 223                         Logger::info('Relay contact not found', ['actor' => $actor]);
 224                         return;
 225                 }
 226
 227                 if (!in_array($contact['rel'], [Contact::SHARING, Contact::FRIEND])) {
 228                         Logger::notice('Relay is no sharer', ['actor' => $actor]);
 229                         return;
 230                 }
 231
 232                 Logger::debug('Got relayed message id', ['id' => $object_id, 'actor' => $actor]);
 233
 234                 $item_id = Item::searchByLink($object_id);
 235                 if ($item_id) {
 236                         Logger::info('Relayed message already exists', ['id' => $object_id, 'item' => $item_id, 'actor' => $actor]);
 237                         return;
 238                 }
 239
 240                 $id = Processor::fetchMissingActivity($object_id, [], $actor, self::COMPLETION_RELAY);
 241                 if (empty($id)) {
 242                         Logger::notice('Relayed message had not been fetched', ['id' => $object_id, 'actor' => $actor]);
 243                         return;
 244                 }
 245         }
 246
 247         /**
 248          * Fetches the object type for a given object id
 249          *
 250          * @param array   $activity
 251          * @param string  $object_id Object ID of the provided object
 252          * @param integer $uid       User ID
 253          *
 254          * @return string with object type or NULL
 255          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 256          * @throws \ImagickException
 257          */
 258         public static function fetchObjectType(array $activity, string $object_id, int $uid = 0)
 259         {
 260                 if (!empty($activity['as:object'])) {
 261                         $object_type = JsonLD::fetchElement($activity['as:object'], '@type');
 262                         if (!empty($object_type)) {
 263                                 return $object_type;
 264                         }
 265                 }
 266
 267                 if (Post::exists(['uri' => $object_id, 'gravity' => [Item::GRAVITY_PARENT, Item::GRAVITY_COMMENT]])) {
 268                         // We just assume "note" since it doesn't make a difference for the further processing
 269                         return 'as:Note';
 270                 }
 271
 272                 $profile = APContact::getByURL($object_id);
 273                 if (!empty($profile['type'])) {
 274                         APContact::unmarkForArchival($profile);
 275                         return 'as:' . $profile['type'];
 276                 }
 277
 278                 $data = Processor::fetchCachedActivity($object_id, $uid);
 279                 if (!empty($data)) {
 280                         $object = JsonLD::compact($data);
 281                         $type = JsonLD::fetchElement($object, '@type');
 282                         if (!empty($type)) {
 283                                 return $type;
 284                         }
 285                 }
 286
 287                 return null;
 288         }
 289
 290         /**
 291          * Prepare the object array
 292          *
 293          * @param array   $activity     Array with activity data
 294          * @param integer $uid          User ID
 295          * @param boolean $push         Message had been pushed to our system
 296          * @param boolean $trust_source Do we trust the source?
 297          *
 298          * @return array with object data
 299          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 300          * @throws \ImagickException
 301          */
 302         public static function prepareObjectData(array $activity, int $uid, bool $push, bool &$trust_source): array
 303         {
 304                 $id        = JsonLD::fetchElement($activity, '@id');
 305                 $type      = JsonLD::fetchElement($activity, '@type');
 306                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 307
 308                 if (!empty($object_id) && in_array($type, ['as:Create', 'as:Update'])) {
 309                         $fetch_id = $object_id;
 310                 } else {
 311                         $fetch_id = $id;
 312                 }
 313
 314                 if (!empty($activity['as:object'])) {
 315                         $object_type = JsonLD::fetchElement($activity['as:object'], '@type');
 316                 }
 317
 318                 $fetched = false;
 319
 320                 if (!empty($id) && !$trust_source) {
 321                         $fetch_uid = $uid ?: self::getBestUserForActivity($activity);
 322
 323                         $fetched_activity = Processor::fetchCachedActivity($fetch_id, $fetch_uid);
 324                         if (!empty($fetched_activity)) {
 325                                 $fetched = true;
 326                                 $object  = JsonLD::compact($fetched_activity);
 327
 328                                 $fetched_id   = JsonLD::fetchElement($object, '@id');
 329                                 $fetched_type = JsonLD::fetchElement($object, '@type');
 330
 331                                 if (($fetched_id == $id) && !empty($fetched_type) && ($fetched_type == $type)) {
 332                                         Logger::info('Activity had been fetched successfully', ['id' => $id]);
 333                                         $trust_source = true;
 334                                         $activity = $object;
 335                                 } elseif (($fetched_id == $object_id) && !empty($fetched_type) && ($fetched_type == $object_type)) {
 336                                         Logger::info('Fetched data is the object instead of the activity', ['id' => $id]);
 337                                         $trust_source = true;
 338                                         unset($object['@context']);
 339                                         $activity['as:object'] = $object;
 340                                 } else {
 341                                         Logger::info('Activity id is not equal', ['id' => $id, 'fetched' => $fetched_id]);
 342                                 }
 343                         } else {
 344                                 Logger::info('Activity could not been fetched', ['id' => $id]);
 345                         }
 346                 }
 347
 348                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 349                 if (empty($actor)) {
 350                         Logger::info('Empty actor', ['activity' => $activity]);
 351                         return [];
 352                 }
 353
 354                 $type = JsonLD::fetchElement($activity, '@type');
 355
 356                 // Fetch all receivers from to, cc, bto and bcc
 357                 $receiverdata = self::getReceivers($activity, $actor, [], false, $push || $fetched);
 358                 $receivers = $reception_types = [];
 359                 foreach ($receiverdata as $key => $data) {
 360                         $receivers[$key] = $data['uid'];
 361                         $reception_types[$data['uid']] = $data['type'] ?? self::TARGET_UNKNOWN;
 362                 }
 363
 364                 $urls = self::getReceiverURL($activity);
 365
 366                 // When it is a delivery to a personal inbox we add that user to the receivers
 367                 if (!empty($uid)) {
 368                         $additional = [$uid => $uid];
 369                         $receivers = array_replace($receivers, $additional);
 370                         if (empty($activity['thread-completion']) && (empty($reception_types[$uid]) || in_array($reception_types[$uid], [self::TARGET_UNKNOWN, self::TARGET_FOLLOWER, self::TARGET_ANSWER, self::TARGET_GLOBAL]))) {
 371                                 $reception_types[$uid] = self::TARGET_BCC;
 372                                 $owner = User::getOwnerDataById($uid);
 373                                 if (!empty($owner['url'])) {
 374                                         $urls['as:bcc'][] = $owner['url'];
 375                                 }
 376                         }
 377                 }
 378
 379                 // We possibly need some user to fetch private content,
 380                 // so we fetch one out of the receivers if no uid is provided.
 381                 $fetch_uid = $uid ?: self::getBestUserForActivity($activity);
 382
 383                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 384                 if (empty($object_id)) {
 385                         Logger::info('No object found');
 386                         return [];
 387                 }
 388
 389                 if (!is_string($object_id)) {
 390                         Logger::info('Invalid object id', ['object' => $object_id]);
 391                         return [];
 392                 }
 393
 394                 $object_type = self::fetchObjectType($activity, $object_id, $fetch_uid);
 395
 396                 // Fetch the activity on Lemmy "Announce" messages (announces of activities)
 397                 if (($type == 'as:Announce') && in_array($object_type, array_merge(self::ACTIVITY_TYPES, ['as:Delete', 'as:Undo', 'as:Update']))) {
 398                         Logger::debug('Fetch announced activity', ['object' => $object_id]);
 399                         $data = Processor::fetchCachedActivity($object_id, $fetch_uid);
 400                         if (!empty($data)) {
 401                                 $type = $object_type;
 402                                 $activity = JsonLD::compact($data);
 403
 404                                 // Some variables need to be refetched since the activity changed
 405                                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 406                                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 407                                 $object_type = self::fetchObjectType($activity, $object_id, $fetch_uid);
 408                         }
 409                 }
 410
 411                 // Any activities on account types must not be altered
 412                 if (in_array($type, ['as:Flag'])) {
 413                         $object_data = [];
 414                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 415                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 416                         $object_data['object_ids'] = JsonLD::fetchElementArray($activity, 'as:object', '@id');
 417                         $object_data['content'] = JsonLD::fetchElement($activity, 'as:content', '@type');
 418                 } elseif (in_array($object_type, self::ACCOUNT_TYPES)) {
 419                         $object_data = [];
 420                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 421                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 422                         $object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor', '@id');
 423                         $object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
 424                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 425                         if (!$trust_source && ($type == 'as:Delete')) {
 426                                 $apcontact = APContact::getByURL($object_data['object_id'], true);
 427                                 $trust_source = empty($apcontact) || ($apcontact['type'] == 'Tombstone') || $apcontact['suspended'];
 428                         }
 429                 } elseif (in_array($type, ['as:Create', 'as:Update', 'as:Invite']) || strpos($type, '#emojiReaction')) {
 430                         // Fetch the content only on activities where this matters
 431                         // We can receive "#emojiReaction" when fetching content from Hubzilla systems
 432                         $object_data = self::fetchObject($object_id, $activity['as:object'], $trust_source, $fetch_uid);
 433                         if (empty($object_data)) {
 434                                 Logger::info("Object data couldn't be processed");
 435                                 return [];
 436                         }
 437
 438                         $object_data['object_id'] = $object_id;
 439
 440                         // Test if it is an answer to a mail
 441                         if (DBA::exists('mail', ['uri' => $object_data['reply-to-id']])) {
 442                                 $object_data['directmessage'] = true;
 443                         } else {
 444                                 $object_data['directmessage'] = JsonLD::fetchElement($activity, 'litepub:directMessage');
 445                         }
 446                 } elseif (in_array($type, array_merge(self::ACTIVITY_TYPES, ['as:Announce', 'as:Follow'])) && in_array($object_type, self::CONTENT_TYPES)) {
 447                         // Create a mostly empty array out of the activity data (instead of the object).
 448                         // This way we later don't have to check for the existence of each individual array element.
 449                         $object_data = self::processObject($activity);
 450                         $object_data['name'] = $type;
 451                         $object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 452                         $object_data['object_id'] = $object_id;
 453                         $object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
 454                 } elseif (in_array($type, ['as:Add', 'as:Remove', 'as:Move'])) {
 455                         $object_data = [];
 456                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 457                         $object_data['target_id'] = JsonLD::fetchElement($activity, 'as:target', '@id');
 458                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 459                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 460                         $object_data['object_content'] = JsonLD::fetchElement($activity['as:object'], 'as:content', '@type');
 461                 } else {
 462                         $object_data = [];
 463                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 464                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 465                         $object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor', '@id');
 466                         $object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
 467                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 468
 469                         // An Undo is done on the object of an object, so we need that type as well
 470                         if (($type == 'as:Undo') && !empty($object_data['object_object'])) {
 471                                 $object_data['object_object_type'] = self::fetchObjectType([], $object_data['object_object'], $fetch_uid);
 472                         }
 473
 474                         if (!$trust_source && ($type == 'as:Delete') && in_array($object_data['object_type'], array_merge(['as:Tombstone', ''], self::CONTENT_TYPES))) {
 475                                 $trust_source = Processor::isActivityGone($object_data['object_id']);
 476                                 if (!$trust_source) {
 477                                         $trust_source = !empty(APContact::getByURL($object_data['object_id'], false));
 478                                 }
 479                         }
 480                 }
 481
 482                 $object_data['push'] = $push;
 483
 484                 $object_data = self::addActivityFields($object_data, $activity);
 485
 486                 if (empty($object_data['object_type'])) {
 487                         $object_data['object_type'] = $object_type;
 488                 }
 489
 490                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
 491                         if ((empty($object_data['receiver_urls'][$element]) || in_array($element, ['as:bto', 'as:bcc'])) && !empty($urls[$element])) {
 492                                 $object_data['receiver_urls'][$element] = array_unique(array_merge($object_data['receiver_urls'][$element] ?? [], $urls[$element]));
 493                         }
 494                 }
 495
 496                 $object_data['type'] = $type;
 497                 $object_data['actor'] = $actor;
 498                 $object_data['item_receiver'] = $receivers;
 499                 $object_data['receiver'] = array_replace($object_data['receiver'] ?? [], $receivers);
 500                 $object_data['reception_type'] = array_replace($object_data['reception_type'] ?? [], $reception_types);
 501
 502 //              This check here interferes with Hubzilla posts where the author host differs from the host the post was created
 503 //              $author = $object_data['author'] ?? $actor;
 504 //              if (!empty($author) && !empty($object_data['id'])) {
 505 //                      $author_host = parse_url($author, PHP_URL_HOST);
 506 //                      $id_host = parse_url($object_data['id'], PHP_URL_HOST);
 507 //                      if ($author_host == $id_host) {
 508 //                              Logger::info('Valid hosts', ['type' => $type, 'host' => $id_host]);
 509 //                      } else {
 510 //                              Logger::notice('Differing hosts on author and id', ['type' => $type, 'author' => $author_host, 'id' => $id_host]);
 511 //                              $trust_source = false;
 512 //                      }
 513 //              }
 514
 515                 $account = Contact::selectFirstAccount(['platform'], ['nurl' => Strings::normaliseLink($actor)]);
 516                 $platform = $account['platform'] ?? '';
 517
 518                 Logger::info('Processing', ['type' => $object_data['type'], 'object_type' => $object_data['object_type'], 'id' => $object_data['id'], 'actor' => $actor, 'platform' => $platform]);
 519
 520                 return $object_data;
 521         }
 522
 523         /**
 524          * Fetches the first user id from the receiver array
 525          *
 526          * @param array $receivers Array with receivers
 527          * @return integer user id;
 528          */
 529         public static function getFirstUserFromReceivers(array $receivers): int
 530         {
 531                 foreach ($receivers as $receiver) {
 532                         if (!empty($receiver)) {
 533                                 return $receiver;
 534                         }
 535                 }
 536                 return 0;
 537         }
 538
 539         /**
 540          * Processes the activity object
 541          *
 542          * @param array      $activity     Array with activity data
 543          * @param string     $body         The unprocessed body
 544          * @param int|null   $uid          User ID
 545          * @param boolean    $trust_source Do we trust the source?
 546          * @param boolean    $push         Message had been pushed to our system
 547          * @param array      $signer       The signer of the post
 548          *
 549          * @return bool
 550          *
 551          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 552          * @throws \ImagickException
 553          */
 554         public static function processActivity(array $activity, string $body = '', int $uid = null, bool $trust_source = false, bool $push = false, array $signer = [], string $http_signer = '', int $completion = Receiver::COMPLETION_AUTO): bool
 555         {
 556                 $type = JsonLD::fetchElement($activity, '@type');
 557                 if (!$type) {
 558                         Logger::info('Empty type', ['activity' => $activity]);
 559                         return true;
 560                 }
 561
 562                 if (!DI::config()->get('system', 'process_view') && ($type == 'as:View')) {
 563                         Logger::info('View activities are ignored.', ['signer' => $signer, 'http_signer' => $http_signer]);
 564                         return true;
 565                 }
 566
 567                 if (!JsonLD::fetchElement($activity, 'as:object', '@id')) {
 568                         Logger::info('Empty object', ['activity' => $activity]);
 569                         return true;
 570                 }
 571
 572                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 573                 if (empty($actor)) {
 574                         Logger::info('Empty actor', ['activity' => $activity]);
 575                         return true;
 576                 }
 577
 578                 if (is_array($activity['as:object'])) {
 579                         $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
 580                 } else {
 581                         $attributed_to = '';
 582                 }
 583
 584                 // Test the provided signatures against the actor and "attributedTo"
 585                 if ($trust_source) {
 586                         if (!empty($attributed_to) && !empty($actor)) {
 587                                 $trust_source = (in_array($actor, $signer) && in_array($attributed_to, $signer));
 588                         } else {
 589                                 $trust_source = in_array($actor, $signer);
 590                         }
 591                 }
 592
 593                 // $trust_source is called by reference and is set to true if the content was retrieved successfully
 594                 $object_data = self::prepareObjectData($activity, $uid, $push, $trust_source);
 595                 if (empty($object_data)) {
 596                         Logger::info('No object data found', ['activity' => $activity]);
 597                         return true;
 598                 }
 599
 600                 // Lemmy is announcing activities.
 601                 // We are changing the announces into regular activities.
 602                 if (($type == 'as:Announce') && in_array($object_data['type'] ?? '', array_merge(self::ACTIVITY_TYPES, ['as:Delete', 'as:Undo', 'as:Update']))) {
 603                         Logger::debug('Change type of announce to activity', ['type' => $object_data['type']]);
 604                         $type = $object_data['type'];
 605                 }
 606
 607                 if (!empty($body) && empty($object_data['raw'])) {
 608                         $object_data['raw'] = $body;
 609                 }
 610
 611                 // Internal flag for thread completion. See Processor.php
 612                 if (!empty($activity['thread-completion'])) {
 613                         $object_data['thread-completion'] = $activity['thread-completion'];
 614                 }
 615
 616                 if (!empty($activity['completion-mode'])) {
 617                         $object_data['completion-mode'] = $activity['completion-mode'];
 618                 }
 619
 620                 if (!empty($activity['thread-children-type'])) {
 621                         $object_data['thread-children-type'] = $activity['thread-children-type'];
 622                 }
 623
 624                 // Internal flag for posts that arrived via relay
 625                 if (!empty($activity['from-relay'])) {
 626                         $object_data['from-relay'] = $activity['from-relay'];
 627                 }
 628
 629                 if ($type == 'as:Announce') {
 630                         $object_data['object_activity'] = $activity;
 631                 }
 632
 633                 if (($type == 'as:Create') && $trust_source && !in_array($completion, [self::COMPLETION_MANUAL, self::COMPLETION_ANNOUNCE])) {
 634                         if (self::hasArrived($object_data['object_id'])) {
 635                                 Logger::info('The activity already arrived.', ['id' => $object_data['object_id']]);
 636                                 return true;
 637                         }
 638                         self::addArrivedId($object_data['object_id']);
 639
 640                         if (Queue::exists($object_data['object_id'], $type)) {
 641                                 Logger::info('The activity is already added.', ['id' => $object_data['object_id']]);
 642                                 return true;
 643                         }
 644                 } elseif (($type == 'as:Create') && $trust_source && !self::hasArrived($object_data['object_id'])) {
 645                         self::addArrivedId($object_data['object_id']);
 646                 }
 647
 648                 $decouple = DI::config()->get('system', 'decoupled_receiver') && !in_array($completion, [self::COMPLETION_MANUAL, self::COMPLETION_ANNOUNCE]);
 649
 650                 if ($decouple && ($trust_source || DI::config()->get('debug', 'ap_inbox_store_untrusted'))) {
 651                         $object_data = Queue::add($object_data, $type, $uid, $http_signer, $push, $trust_source);
 652                 }
 653
 654                 if (!$trust_source) {
 655                         Logger::info('Activity trust could not be achieved.',  ['id' => $object_data['object_id'], 'type' => $type, 'signer' => $signer, 'actor' => $actor, 'attributedTo' => $attributed_to]);
 656                         return true;
 657                 }
 658
 659                 if (!empty($object_data['entry-id']) && $decouple && ($push || ($completion == self::COMPLETION_RELAY))) {
 660                         if (Queue::isProcessable($object_data['entry-id'])) {
 661                                 // We delay by 5 seconds to allow to accumulate all receivers
 662                                 $delayed = date(DateTimeFormat::MYSQL, time() + 5);
 663                                 Logger::debug('Initiate processing', ['id' => $object_data['entry-id'], 'uri' => $object_data['object_id']]);
 664                                 $wid = Worker::add(['priority' => Worker::PRIORITY_HIGH, 'delayed' => $delayed], 'ProcessQueue', $object_data['entry-id']);
 665                                 Queue::setWorkerId($object_data['entry-id'], $wid);
 666                         } else {
 667                                 Logger::debug('Other queue entries need to be processed first.', ['id' => $object_data['entry-id']]);
 668                         }
 669                         return false;
 670                 }
 671
 672                 if (!empty($activity['recursion-depth'])) {
 673                         $object_data['recursion-depth'] = $activity['recursion-depth'];
 674                 }
 675
 676                 if (!self::routeActivities($object_data, $type, $push, true, $uid)) {
 677                         self::storeUnhandledActivity(true, $type, $object_data, $activity, $body, $uid, $trust_source, $push, $signer);
 678                         Queue::remove($object_data);
 679                 }
 680                 return true;
 681         }
 682
 683         /**
 684          * Route activities
 685          *
 686          * @param array  $object_data
 687          * @param string $type
 688          * @param bool   $push
 689          * @param bool   $fetch_parents
 690          * @param int    $uid
 691          *
 692          * @return boolean Could the activity be routed?
 693          */
 694         public static function routeActivities(array $object_data, string $type, bool $push, bool $fetch_parents = true, int $uid = 0): bool
 695         {
 696                 switch ($type) {
 697                         case 'as:Create':
 698                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 699                                         $item = ActivityPub\Processor::createItem($object_data, $fetch_parents);
 700                                         ActivityPub\Processor::postItem($object_data, $item);
 701                                 } elseif (in_array($object_data['object_type'], ['pt:CacheFile'])) {
 702                                         // Unhandled Peertube activity
 703                                         Queue::remove($object_data);
 704                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 705                                         ActivityPub\Processor::updatePerson($object_data);
 706                                 } else {
 707                                         return false;
 708                                 }
 709                                 break;
 710
 711                         case 'as:Invite':
 712                                 if (in_array($object_data['object_type'], ['as:Event'])) {
 713                                         $item = ActivityPub\Processor::createItem($object_data, $fetch_parents);
 714                                         ActivityPub\Processor::postItem($object_data, $item);
 715                                 } else {
 716                                         return false;
 717                                 }
 718                                 break;
 719
 720                         case 'as:Add':
 721                                 if ($object_data['object_type'] == 'as:tag') {
 722                                         ActivityPub\Processor::addTag($object_data);
 723                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 724                                         ActivityPub\Processor::addToFeaturedCollection($object_data);
 725                                 } elseif (in_array($object_data['object_type'], ['as:Tombstone', ''])) {
 726                                         // We don't have the object here or it is deleted. We ignore this activity.
 727                                         Queue::remove($object_data);
 728                                 } else {
 729                                         return false;
 730                                 }
 731                                 break;
 732
 733                         case 'as:Announce':
 734                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 735                                         if (!Item::searchByLink($object_data['object_id'], $uid)) {
 736                                                 if (ActivityPub\Processor::fetchMissingActivity($object_data['object_id'], [], $object_data['actor'], self::COMPLETION_ANNOUNCE, $uid)) {
 737                                                         Logger::debug('Created announced id', ['uid' => $uid, 'id' => $object_data['object_id']]);
 738                                                         Queue::remove($object_data);
 739                                                 } else {
 740                                                         Logger::debug('Announced id was not created', ['uid' => $uid, 'id' => $object_data['object_id']]);
 741                                                         Queue::remove($object_data);
 742                                                         return true;
 743                                                 }
 744                                         } else {
 745                                                 Logger::info('Announced id already exists', ['uid' => $uid, 'id' => $object_data['object_id']]);
 746                                                 Queue::remove($object_data);
 747                                         }
 748
 749                                         ActivityPub\Processor::createActivity($object_data, Activity::ANNOUNCE);
 750                                 } elseif (in_array($object_data['object_type'], ['as:Tombstone', ''])) {
 751                                         // We don't have the object here or it is deleted. We ignore this activity.
 752                                         Queue::remove($object_data);
 753                                 } else {
 754                                         return false;
 755                                 }
 756                                 break;
 757
 758                         case 'as:Like':
 759                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 760                                         ActivityPub\Processor::createActivity($object_data, Activity::LIKE);
 761                                 } elseif (in_array($object_data['object_type'], ['as:Tombstone', ''])) {
 762                                         // We don't have the object here or it is deleted. We ignore this activity.
 763                                         Queue::remove($object_data);
 764                                 } else {
 765                                         return false;
 766                                 }
 767                                 break;
 768
 769                         case 'as:Dislike':
 770                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 771                                         ActivityPub\Processor::createActivity($object_data, Activity::DISLIKE);
 772                                 } elseif (in_array($object_data['object_type'], ['as:Tombstone', ''])) {
 773                                         // We don't have the object here or it is deleted. We ignore this activity.
 774                                         Queue::remove($object_data);
 775                                 } else {
 776                                         return false;
 777                                 }
 778                                 break;
 779
 780                         case 'as:TentativeAccept':
 781                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 782                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDMAYBE);
 783                                 } else {
 784                                         return false;
 785                                 }
 786                                 break;
 787
 788                         case 'as:Update':
 789                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 790                                         ActivityPub\Processor::updateItem($object_data);
 791                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 792                                         ActivityPub\Processor::updatePerson($object_data);
 793                                 } elseif (in_array($object_data['object_type'], ['pt:CacheFile'])) {
 794                                         // Unhandled Peertube activity
 795                                         Queue::remove($object_data);
 796                                 } else {
 797                                         return false;
 798                                 }
 799                                 break;
 800
 801                         case 'as:Delete':
 802                                 if (in_array($object_data['object_type'], array_merge(['as:Tombstone'], self::CONTENT_TYPES))) {
 803                                         ActivityPub\Processor::deleteItem($object_data);
 804                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 805                                         ActivityPub\Processor::deletePerson($object_data);
 806                                 } elseif ($object_data['object_type'] == '') {
 807                                         // The object type couldn't be determined. Most likely we don't have it here. We ignore this activity.
 808                                         Queue::remove($object_data);
 809                                 } else {
 810                                         return false;
 811                                 }
 812                                 break;
 813
 814                         case 'as:Move':
 815                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 816                                         ActivityPub\Processor::movePerson($object_data);
 817                                 } else {
 818                                         return false;
 819                                 }
 820                                 break;
 821
 822                         case 'as:Block':
 823                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 824                                         ActivityPub\Processor::blockAccount($object_data);
 825                                 } else {
 826                                         return false;
 827                                 }
 828                                 break;
 829
 830                         case 'as:Flag':
 831                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 832                                         ActivityPub\Processor::ReportAccount($object_data);
 833                                 } else {
 834                                         return false;
 835                                 }
 836                                 break;
 837
 838                         case 'as:Remove':
 839                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 840                                         ActivityPub\Processor::removeFromFeaturedCollection($object_data);
 841                                 } elseif (in_array($object_data['object_type'], ['as:Tombstone', ''])) {
 842                                         // We don't have the object here or it is deleted. We ignore this activity.
 843                                         Queue::remove($object_data);
 844                                 } else {
 845                                         return false;
 846                                 }
 847                                 break;
 848
 849                         case 'as:Follow':
 850                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 851                                         ActivityPub\Processor::followUser($object_data);
 852                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 853                                         $object_data['reply-to-id'] = $object_data['object_id'];
 854                                         ActivityPub\Processor::createActivity($object_data, Activity::FOLLOW);
 855                                 } else {
 856                                         return false;
 857                                 }
 858                                 break;
 859
 860                         case 'as:Accept':
 861                                 if ($object_data['object_type'] == 'as:Follow') {
 862                                         if (!empty($object_data['object_actor'])) {
 863                                                 ActivityPub\Processor::acceptFollowUser($object_data);
 864                                         } else {
 865                                                 Logger::notice('Unhandled "accept follow" message.', ['object_data' => $object_data]);
 866                                         }
 867                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 868                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTEND);
 869                                 } elseif (!empty($object_data['object_id']) && empty($object_data['object_actor']) && empty($object_data['object_type'])) {
 870                                         // Follow acceptances from gup.pe only contain the object id
 871                                         ActivityPub\Processor::acceptFollowUser($object_data);
 872                                 } else {
 873                                         return false;
 874                                 }
 875                                 break;
 876
 877                         case 'as:Reject':
 878                                 if ($object_data['object_type'] == 'as:Follow') {
 879                                         ActivityPub\Processor::rejectFollowUser($object_data);
 880                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 881                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDNO);
 882                                 } else {
 883                                         return false;
 884                                 }
 885                                 break;
 886
 887                         case 'as:Undo':
 888                                 if (($object_data['object_type'] == 'as:Follow') &&
 889                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 890                                         ActivityPub\Processor::undoFollowUser($object_data);
 891                                 } elseif (($object_data['object_type'] == 'as:Follow') &&
 892                                         in_array($object_data['object_object_type'], self::CONTENT_TYPES)) {
 893                                         ActivityPub\Processor::undoActivity($object_data);
 894                                 } elseif (($object_data['object_type'] == 'as:Accept') &&
 895                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 896                                         ActivityPub\Processor::rejectFollowUser($object_data);
 897                                 } elseif (($object_data['object_type'] == 'as:Block') &&
 898                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 899                                         ActivityPub\Processor::unblockAccount($object_data);
 900                                 } elseif (in_array($object_data['object_type'], array_merge(self::ACTIVITY_TYPES, ['as:Announce', 'as:Create', ''])) &&
 901                                         empty($object_data['object_object_type'])) {
 902                                         // We cannot detect the target object. So we can ignore it.
 903                                         Queue::remove($object_data);
 904                                 } elseif (in_array($object_data['object_type'], array_merge(self::ACTIVITY_TYPES, ['as:Announce'])) &&
 905                                         in_array($object_data['object_object_type'], array_merge(['as:Tombstone'], self::CONTENT_TYPES))) {
 906                                         ActivityPub\Processor::undoActivity($object_data);
 907                                 } elseif (in_array($object_data['object_type'], ['as:Create']) &&
 908                                         in_array($object_data['object_object_type'], ['pt:CacheFile'])) {
 909                                         // Unhandled Peertube activity
 910                                         Queue::remove($object_data);
 911                                 } elseif (in_array($object_data['object_type'], ['as:Delete'])) {
 912                                         // We cannot undo deletions, so we just ignore this
 913                                         Queue::remove($object_data);
 914                                 } elseif (in_array($object_data['object_object_type'], ['as:Tombstone'])) {
 915                                         // The object is a tombstone, we ignore any actions on it.
 916                                         Queue::remove($object_data);
 917                                 } else {
 918                                         return false;
 919                                 }
 920                                 break;
 921
 922                         case 'as:View':
 923                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 924                                         ActivityPub\Processor::createActivity($object_data, Activity::VIEW);
 925                                 } elseif (in_array($object_data['object_type'], ['as:Tombstone', ''])) {
 926                                         // We don't have the object here or it is deleted. We ignore this activity.
 927                                         Queue::remove($object_data);
 928                                 } else {
 929                                         return false;
 930                                 }
 931                                 break;
 932                         case 'as:Read':
 933                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 934                                         ActivityPub\Processor::createActivity($object_data, Activity::READ);
 935                                 } elseif (in_array($object_data['object_type'], ['as:Tombstone', ''])) {
 936                                         // We don't have the object here or it is deleted. We ignore this activity.
 937                                         Queue::remove($object_data);
 938                                 } else {
 939                                         return false;
 940                                 }
 941                                 break;
 942
 943                         case 'litepub:EmojiReact':
 944                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 945                                         ActivityPub\Processor::createActivity($object_data, Activity::EMOJIREACT);
 946                                 } elseif (in_array($object_data['object_type'], ['as:Tombstone', ''])) {
 947                                         // We don't have the object here or it is deleted. We ignore this activity.
 948                                         Queue::remove($object_data);
 949                                 } else {
 950                                         return false;
 951                                 }
 952                                 break;
 953
 954                         default:
 955                                 Logger::info('Unknown activity: ' . $type . ' ' . $object_data['object_type']);
 956                                 return false;
 957                 }
 958                 return true;
 959         }
 960
 961         /**
 962          * Stores unhandled or unknown Activities as a file
 963          *
 964          * @param boolean $unknown      "true" if the activity is unknown, "false" if it is unhandled
 965          * @param string  $type         Activity type
 966          * @param array   $object_data  Preprocessed array that is generated out of the received activity
 967          * @param array   $activity     Array with activity data
 968          * @param string  $body         The unprocessed body
 969          * @param integer $uid          User ID
 970          * @param boolean $trust_source Do we trust the source?
 971          * @param boolean $push         Message had been pushed to our system
 972          * @param array   $signer       The signer of the post
 973          * @return void
 974          */
 975         private static function storeUnhandledActivity(bool $unknown, string $type, array $object_data, array $activity, string $body = '', int $uid = null, bool $trust_source = false, bool $push = false, array $signer = [])
 976         {
 977                 if (!DI::config()->get('debug', 'ap_log_unknown')) {
 978                         return;
 979                 }
 980
 981                 $file = ($unknown  ? 'unknown-' : 'unhandled-') . str_replace(':', '-', $type) . '-';
 982
 983                 if (!empty($object_data['object_type'])) {
 984                         $file .= str_replace(':', '-', $object_data['object_type']) . '-';
 985                 }
 986
 987                 if (!empty($object_data['object_object_type'])) {
 988                         $file .= str_replace(':', '-', $object_data['object_object_type']) . '-';
 989                 }
 990
 991                 $tempfile = tempnam(System::getTempPath(), $file);
 992                 file_put_contents($tempfile, json_encode(['activity' => $activity, 'body' => $body, 'uid' => $uid, 'trust_source' => $trust_source, 'push' => $push, 'signer' => $signer, 'object_data' => $object_data], JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE | JSON_PRETTY_PRINT));
 993                 Logger::notice('Unknown activity stored', ['type' => $type, 'object_type' => $object_data['object_type'], 'object_object_type' => $object_data['object_object_type'] ?? '', 'file' => $tempfile]);
 994         }
 995
 996         /**
 997          * Fetch a user id from an activity array
 998          *
 999          * @param array  $activity
1000          * @param string $actor
1001          *
1002          * @return int   user id
1003          */
1004         public static function getBestUserForActivity(array $activity): int
1005         {
1006                 $uid = 0;
1007                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id') ?? '';
1008
1009                 $receivers = self::getReceivers($activity, $actor, [], false, false);
1010                 foreach ($receivers as $receiver) {
1011                         if ($receiver['type'] == self::TARGET_GLOBAL) {
1012                                 return 0;
1013                         }
1014                         if (empty($uid) || ($receiver['type'] == self::TARGET_TO)) {
1015                                 $uid = $receiver['uid'];
1016                         }
1017                 }
1018
1019                 // When we haven't found any user yet, we just chose a user who most likely could have access to the content
1020                 if (empty($uid)) {
1021                         $contact = Contact::selectFirst(['uid'], ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND]]);
1022                         if (!empty($contact['uid'])) {
1023                                 $uid = $contact['uid'];
1024                         }
1025                 }
1026
1027                 return $uid;
1028         }
1029
1030         // @TODO Missing documentation
1031         public static function getReceiverURL(array $activity): array
1032         {
1033                 $urls = [];
1034
1035                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
1036                         $receiver_list = JsonLD::fetchElementArray($activity, $element, '@id');
1037                         if (empty($receiver_list)) {
1038                                 continue;
1039                         }
1040
1041                         foreach ($receiver_list as $receiver) {
1042                                 if ($receiver == 'Public') {
1043                                         Logger::warning('Not compacted public collection found', ['activity' => $activity, 'callstack' => System::callstack(20)]);
1044                                         $receiver = ActivityPub::PUBLIC_COLLECTION;
1045                                 }
1046                                 if ($receiver == self::PUBLIC_COLLECTION) {
1047                                         $receiver = ActivityPub::PUBLIC_COLLECTION;
1048                                 }
1049                                 $urls[$element][] = $receiver;
1050                         }
1051                 }
1052
1053                 return $urls;
1054         }
1055
1056         /**
1057          * Fetch the receiver list from an activity array
1058          *
1059          * @param array   $activity
1060          * @param string $actor
1061          * @param array  $tags
1062          * @param bool   $fetch_unlisted
1063          * @param bool   $push
1064          *
1065          * @return array with receivers (user id)
1066          * @throws \Exception
1067          */
1068         private static function getReceivers(array $activity, string $actor, array $tags, bool $fetch_unlisted, bool $push): array
1069         {
1070                 $reply = $receivers = $profile = [];
1071
1072                 // When it is an answer, we inherit the receivers from the parent
1073                 $replyto = JsonLD::fetchElement($activity, 'as:inReplyTo', '@id');
1074                 if (!empty($replyto)) {
1075                         $reply = [$replyto];
1076
1077                         // Fix possibly wrong item URI (could be an answer to a plink uri)
1078                         $fixedReplyTo = Item::getURIByLink($replyto);
1079                         if (!empty($fixedReplyTo)) {
1080                                 $reply[] = $fixedReplyTo;
1081                         }
1082                 }
1083
1084                 // Fetch all posts that refer to the object id
1085                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
1086                 if (!empty($object_id)) {
1087                         $reply[] = $object_id;
1088                 }
1089
1090                 if (!empty($actor)) {
1091                         $profile   = APContact::getByURL($actor);
1092                         $followers = $profile['followers'] ?? '';
1093                         $is_forum  = ($actor['type'] ?? '') == 'Group';
1094                         if ($push) {
1095                                 Contact::updateByUrlIfNeeded($actor);
1096                         }
1097                         Logger::info('Got actor and followers', ['actor' => $actor, 'followers' => $followers]);
1098                 } else {
1099                         Logger::info('Empty actor', ['activity' => $activity]);
1100                         $followers = '';
1101                         $is_forum  = false;
1102                 }
1103
1104                 // We have to prevent false follower assumptions upon thread completions
1105                 $follower_target = empty($activity['thread-completion']) ? self::TARGET_FOLLOWER : self::TARGET_UNKNOWN;
1106
1107                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
1108                         $receiver_list = JsonLD::fetchElementArray($activity, $element, '@id');
1109                         if (empty($receiver_list)) {
1110                                 continue;
1111                         }
1112
1113                         foreach ($receiver_list as $receiver) {
1114                                 if ($receiver == self::PUBLIC_COLLECTION) {
1115                                         $receivers[0] = ['uid' => 0, 'type' => self::TARGET_GLOBAL];
1116                                 }
1117
1118                                 // Add receiver "-1" for unlisted posts
1119                                 if ($fetch_unlisted && ($receiver == self::PUBLIC_COLLECTION) && ($element == 'as:cc')) {
1120                                         $receivers[-1] = ['uid' => -1, 'type' => self::TARGET_GLOBAL];
1121                                 }
1122
1123                                 // Fetch the receivers for the public and the followers collection
1124                                 if ((($receiver == $followers) || (($receiver == self::PUBLIC_COLLECTION) && !$is_forum)) && !empty($actor)) {
1125                                         $receivers = self::getReceiverForActor($actor, $tags, $receivers, $follower_target, $profile);
1126                                         continue;
1127                                 }
1128
1129                                 // Fetching all directly addressed receivers
1130                                 $condition = ['self' => true, 'nurl' => Strings::normaliseLink($receiver)];
1131                                 $contact = DBA::selectFirst('contact', ['uid', 'contact-type'], $condition);
1132                                 if (!DBA::isResult($contact)) {
1133                                         continue;
1134                                 }
1135
1136                                 // Check if the potential receiver is following the actor
1137                                 // Exception: The receiver is targetted via "to" or this is a comment
1138                                 if ((($element != 'as:to') && empty($replyto)) || ($contact['contact-type'] == Contact::TYPE_COMMUNITY)) {
1139                                         $networks = Protocol::FEDERATED;
1140                                         $condition = ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
1141                                                 'network' => $networks, 'archive' => false, 'pending' => false, 'uid' => $contact['uid']];
1142
1143                                         // Forum posts are only accepted from forum contacts
1144                                         if ($contact['contact-type'] == Contact::TYPE_COMMUNITY) {
1145                                                 $condition['rel'] = [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER];
1146                                         }
1147
1148                                         if (!DBA::exists('contact', $condition)) {
1149                                                 continue;
1150                                         }
1151                                 }
1152
1153                                 $type = $receivers[$contact['uid']]['type'] ?? self::TARGET_UNKNOWN;
1154                                 if (in_array($type, [self::TARGET_UNKNOWN, self::TARGET_FOLLOWER, self::TARGET_ANSWER, self::TARGET_GLOBAL])) {
1155                                         switch ($element) {
1156                                                 case 'as:to':
1157                                                         $type = self::TARGET_TO;
1158                                                         break;
1159                                                 case 'as:cc':
1160                                                         $type = self::TARGET_CC;
1161                                                         break;
1162                                                 case 'as:bto':
1163                                                         $type = self::TARGET_BTO;
1164                                                         break;
1165                                                 case 'as:bcc':
1166                                                         $type = self::TARGET_BCC;
1167                                                         break;
1168                                         }
1169
1170                                         $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $type];
1171                                 }
1172                         }
1173                 }
1174
1175                 if (!empty($reply) && (!empty($receivers[0]) || !empty($receivers[-1]))) {
1176                         $parents = Post::select(['uid'], DBA::mergeConditions(['uri' => $reply], ["`uid` != ?", 0]));
1177                         while ($parent = Post::fetch($parents)) {
1178                                 $receivers[$parent['uid']] = ['uid' => $parent['uid'], 'type' => self::TARGET_ANSWER];
1179                         }
1180                         DBA::close($parents);
1181                 }
1182
1183                 self::switchContacts($receivers, $actor);
1184
1185                 // "birdsitelive" is a service that mirrors tweets into the fediverse
1186                 // These posts can be fetched without authentication, but are not marked as public
1187                 // We treat them as unlisted posts to be able to handle them.
1188                 if (empty($receivers) && $fetch_unlisted && Contact::isPlatform($actor, 'birdsitelive')) {
1189                         $receivers[0]  = ['uid' => 0, 'type' => self::TARGET_GLOBAL];
1190                         $receivers[-1] = ['uid' => -1, 'type' => self::TARGET_GLOBAL];
1191                         Logger::notice('Post from "birdsitelive" is set to "unlisted"', ['id' => JsonLD::fetchElement($activity, '@id')]);
1192                 } elseif (empty($receivers)) {
1193                         Logger::notice('Post has got no receivers', ['fetch_unlisted' => $fetch_unlisted, 'actor' => $actor, 'id' => JsonLD::fetchElement($activity, '@id'), 'type' => JsonLD::fetchElement($activity, '@type')]);
1194                 }
1195
1196                 return $receivers;
1197         }
1198
1199         /**
1200          * Fetch the receiver list of a given actor
1201          *
1202          * @param string  $actor
1203          * @param array   $tags
1204          * @param array   $receivers
1205          * @param integer $target_type
1206          * @param array   $profile
1207          *
1208          * @return array with receivers (user id)
1209          * @throws \Exception
1210          */
1211         private static function getReceiverForActor(string $actor, array $tags, array $receivers, int $target_type, array $profile): array
1212         {
1213                 $basecondition = ['rel' => [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER],
1214                         'network' => Protocol::FEDERATED, 'archive' => false, 'pending' => false];
1215
1216                 if (!empty($profile['uri-id'])) {
1217                         $condition = DBA::mergeConditions($basecondition, ["`uri-id` = ? AND `uid` != ?", $profile['uri-id'], 0]);
1218                         $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
1219                         while ($contact = DBA::fetch($contacts)) {
1220                                 if (empty($receivers[$contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
1221                                         $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $target_type];
1222                                 }
1223                         }
1224                         DBA::close($contacts);
1225                 } else {
1226                         // This part will only be called while post update 1426 wasn't finished
1227                         $condition = DBA::mergeConditions($basecondition, ["`nurl` = ? AND `uid` != ?", Strings::normaliseLink($actor), 0]);
1228                         $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
1229                         while ($contact = DBA::fetch($contacts)) {
1230                                 if (empty($receivers[$contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
1231                                         $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $target_type];
1232                                 }
1233                         }
1234                         DBA::close($contacts);
1235
1236                         // The queries are split because of performance issues
1237                         $condition = DBA::mergeConditions($basecondition, ["`alias` IN (?, ?) AND `uid` != ?", Strings::normaliseLink($actor), $actor, 0]);
1238                         $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
1239                         while ($contact = DBA::fetch($contacts)) {
1240                                 if (empty($receivers[$contact['uid']]) && self::isValidReceiverForActor($contact, $tags)) {
1241                                         $receivers[$contact['uid']] = ['uid' => $contact['uid'], 'type' => $target_type];
1242                                 }
1243                         }
1244                         DBA::close($contacts);
1245                 }
1246                 return $receivers;
1247         }
1248
1249         /**
1250          * Tests if the contact is a valid receiver for this actor
1251          *
1252          * @param array  $contact
1253          * @param array  $tags
1254          *
1255          * @return bool with receivers (user id)
1256          * @throws \Exception
1257          */
1258         private static function isValidReceiverForActor(array $contact, array $tags): bool
1259         {
1260                 // Are we following the contact? Then this is a valid receiver
1261                 if (in_array($contact['rel'], [Contact::SHARING, Contact::FRIEND])) {
1262                         return true;
1263                 }
1264
1265                 // When the possible receiver isn't a community, then it is no valid receiver
1266                 $owner = User::getOwnerDataById($contact['uid']);
1267                 if (empty($owner) || ($owner['contact-type'] != Contact::TYPE_COMMUNITY)) {
1268                         return false;
1269                 }
1270
1271                 // Is the community account tagged?
1272                 foreach ($tags as $tag) {
1273                         if ($tag['type'] != 'Mention') {
1274                                 continue;
1275                         }
1276
1277                         if (Strings::compareLink($tag['href'], $owner['url'])) {
1278                                 return true;
1279                         }
1280                 }
1281
1282                 return false;
1283         }
1284
1285         /**
1286          * Switches existing contacts to ActivityPub
1287          *
1288          * @param integer $cid Contact ID
1289          * @param integer $uid User ID
1290          * @param string  $url Profile URL
1291          * @return void
1292          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1293          * @throws \ImagickException
1294          */
1295         public static function switchContact(int $cid, int $uid, string $url)
1296         {
1297                 if (DBA::exists('contact', ['id' => $cid, 'network' => Protocol::ACTIVITYPUB])) {
1298                         Logger::info('Contact is already ActivityPub', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
1299                         return;
1300                 }
1301
1302                 if (Contact::updateFromProbe($cid)) {
1303                         Logger::info('Update was successful', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
1304                 }
1305
1306                 // Send a new follow request to be sure that the connection still exists
1307                 if (($uid != 0) && DBA::exists('contact', ['id' => $cid, 'rel' => [Contact::SHARING, Contact::FRIEND], 'network' => Protocol::ACTIVITYPUB])) {
1308                         Logger::info('Contact had been switched to ActivityPub. Sending a new follow request.', ['uid' => $uid, 'url' => $url]);
1309                         ActivityPub\Transmitter::sendActivity('Follow', $url, $uid);
1310                 }
1311         }
1312
1313         /**
1314          * @TODO Fix documentation and type-hints
1315          *
1316          * @param $receivers
1317          * @param $actor
1318          * @return void
1319          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1320          * @throws \ImagickException
1321          */
1322         private static function switchContacts($receivers, $actor)
1323         {
1324                 if (empty($actor)) {
1325                         return;
1326                 }
1327
1328                 foreach ($receivers as $receiver) {
1329                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver['uid'], 'network' => Protocol::OSTATUS, 'nurl' => Strings::normaliseLink($actor)]);
1330                         if (DBA::isResult($contact)) {
1331                                 self::switchContact($contact['id'], $receiver['uid'], $actor);
1332                         }
1333
1334                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver['uid'], 'network' => Protocol::OSTATUS, 'alias' => [Strings::normaliseLink($actor), $actor]]);
1335                         if (DBA::isResult($contact)) {
1336                                 self::switchContact($contact['id'], $receiver['uid'], $actor);
1337                         }
1338                 }
1339         }
1340
1341         /**
1342          * @TODO Fix documentation and type-hints
1343          *
1344          * @param       $object_data
1345          * @param array $activity
1346          *
1347          * @return mixed
1348          */
1349         private static function addActivityFields($object_data, array $activity)
1350         {
1351                 if (!empty($activity['published']) && empty($object_data['published'])) {
1352                         $object_data['published'] = JsonLD::fetchElement($activity, 'as:published', '@value');
1353                 }
1354
1355                 if (!empty($activity['diaspora:guid']) && empty($object_data['diaspora:guid'])) {
1356                         $object_data['diaspora:guid'] = JsonLD::fetchElement($activity, 'diaspora:guid', '@value');
1357                 }
1358
1359                 $object_data['service'] = JsonLD::fetchElement($activity, 'as:instrument', 'as:name', '@type', 'as:Service');
1360                 $object_data['service'] = JsonLD::fetchElement($object_data, 'service', '@value');
1361
1362                 if (!empty($object_data['object_id'])) {
1363                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
1364                         $objectId = Item::getURIByLink($object_data['object_id']);
1365                         if (!empty($objectId) && ($object_data['object_id'] != $objectId)) {
1366                                 Logger::notice('Fix wrong object-id', ['received' => $object_data['object_id'], 'correct' => $objectId]);
1367                                 $object_data['object_id'] = $objectId;
1368                         }
1369                 }
1370
1371                 return $object_data;
1372         }
1373
1374         /**
1375          * Fetches the object data from external resources if needed
1376          *
1377          * @param string  $object_id    Object ID of the provided object
1378          * @param array   $object       The provided object array
1379          * @param boolean $trust_source Do we trust the provided object?
1380          * @param integer $uid          User ID for the signature that we use to fetch data
1381          *
1382          * @return array|false with trusted and valid object data
1383          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
1384          * @throws \ImagickException
1385          */
1386         private static function fetchObject(string $object_id, array $object = [], bool $trust_source = false, int $uid = 0)
1387         {
1388                 // By fetching the type we check if the object is complete.
1389                 $type = JsonLD::fetchElement($object, '@type');
1390
1391                 if (!$trust_source || empty($type)) {
1392                         $data = Processor::fetchCachedActivity($object_id, $uid);
1393                         if (!empty($data)) {
1394                                 $object = JsonLD::compact($data);
1395                                 Logger::info('Fetched content for ' . $object_id);
1396                         } else {
1397                                 Logger::info('Empty content for ' . $object_id . ', check if content is available locally.');
1398
1399                                 $item = Post::selectFirst(Item::DELIVER_FIELDLIST, ['uri' => $object_id]);
1400                                 if (!DBA::isResult($item)) {
1401                                         Logger::info('Object with url ' . $object_id . ' was not found locally.');
1402                                         return false;
1403                                 }
1404                                 Logger::info('Using already stored item for url ' . $object_id);
1405                                 $data = ActivityPub\Transmitter::createNote($item);
1406                                 $object = JsonLD::compact($data);
1407                         }
1408
1409                         $id = JsonLD::fetchElement($object, '@id');
1410                         if (empty($id)) {
1411                                 Logger::info('Empty id');
1412                                 return false;
1413                         }
1414
1415                         if ($id != $object_id) {
1416                                 Logger::info('Fetched id differs from provided id', ['provided' => $object_id, 'fetched' => $id]);
1417                                 return false;
1418                         }
1419                 } else {
1420                         Logger::info('Using original object for url ' . $object_id);
1421                 }
1422
1423                 $type = JsonLD::fetchElement($object, '@type');
1424                 if (empty($type)) {
1425                         Logger::info('Empty type');
1426                         return false;
1427                 }
1428
1429                 // Lemmy is resharing "create" activities instead of content
1430                 // We fetch the content from the activity.
1431                 if (in_array($type, ['as:Create'])) {
1432                         $object = $object['as:object'];
1433                         $type = JsonLD::fetchElement($object, '@type');
1434                         if (empty($type)) {
1435                                 Logger::info('Empty type');
1436                                 return false;
1437                         }
1438                         $object_data = self::processObject($object);
1439                 }
1440
1441                 // We currently don't handle 'pt:CacheFile', but with this step we avoid logging
1442                 if (in_array($type, self::CONTENT_TYPES) || ($type == 'pt:CacheFile')) {
1443                         $object_data = self::processObject($object);
1444
1445                         if (!empty($data)) {
1446                                 $object_data['raw-object'] = json_encode($data);
1447                         }
1448                         return $object_data;
1449                 }
1450
1451                 Logger::info('Unhandled object type: ' . $type);
1452                 return false;
1453         }
1454
1455         /**
1456          * Converts the language element (Used by Peertube)
1457          *
1458          * @param array $languages
1459          * @return array Languages
1460          */
1461         public static function processLanguages(array $languages): array
1462         {
1463                 if (empty($languages)) {
1464                         return [];
1465                 }
1466
1467                 $language_list = [];
1468
1469                 foreach ($languages as $language) {
1470                         if (!empty($language['_:identifier']) && !empty($language['as:name'])) {
1471                                 $language_list[$language['_:identifier']] = $language['as:name'];
1472                         }
1473                 }
1474                 return $language_list;
1475         }
1476
1477         /**
1478          * Convert tags from JSON-LD format into a simplified format
1479          *
1480          * @param array $tags Tags in JSON-LD format
1481          *
1482          * @return array with tags in a simplified format
1483          */
1484         public static function processTags(array $tags): array
1485         {
1486                 $taglist = [];
1487
1488                 foreach ($tags as $tag) {
1489                         if (empty($tag)) {
1490                                 continue;
1491                         }
1492
1493                         $element = ['type' => str_replace('as:', '', JsonLD::fetchElement($tag, '@type') ?? ''),
1494                                 'href' => JsonLD::fetchElement($tag, 'as:href', '@id'),
1495                                 'name' => JsonLD::fetchElement($tag, 'as:name', '@value')];
1496
1497                         if (empty($element['type'])) {
1498                                 continue;
1499                         }
1500
1501                         if (empty($element['href'])) {
1502                                 $element['href'] = $element['name'];
1503                         }
1504
1505                         $taglist[] = $element;
1506                 }
1507                 return $taglist;
1508         }
1509
1510         /**
1511          * Convert emojis from JSON-LD format into a simplified format
1512          *
1513          * @param array $emojis
1514          * @return array with emojis in a simplified format
1515          */
1516         private static function processEmojis(array $emojis): array
1517         {
1518                 $emojilist = [];
1519
1520                 foreach ($emojis as $emoji) {
1521                         if (empty($emoji) || (JsonLD::fetchElement($emoji, '@type') != 'toot:Emoji') || empty($emoji['as:icon'])) {
1522                                 continue;
1523                         }
1524
1525                         $url = JsonLD::fetchElement($emoji['as:icon'], 'as:url', '@id');
1526                         $element = ['name' => JsonLD::fetchElement($emoji, 'as:name', '@value'),
1527                                 'href' => $url];
1528
1529                         $emojilist[] = $element;
1530                 }
1531
1532                 return $emojilist;
1533         }
1534
1535         /**
1536          * Convert attachments from JSON-LD format into a simplified format
1537          *
1538          * @param array $attachments Attachments in JSON-LD format
1539          *
1540          * @return array Attachments in a simplified format
1541          */
1542         private static function processAttachments(array $attachments): array
1543         {
1544                 $attachlist = [];
1545
1546                 // Removes empty values
1547                 $attachments = array_filter($attachments);
1548
1549                 foreach ($attachments as $attachment) {
1550                         switch (JsonLD::fetchElement($attachment, '@type')) {
1551                                 case 'as:Page':
1552                                         $pageUrl = null;
1553                                         $pageImage = null;
1554
1555                                         $urls = JsonLD::fetchElementArray($attachment, 'as:url');
1556                                         foreach ($urls as $url) {
1557                                                 // Single scalar URL case
1558                                                 if (is_string($url)) {
1559                                                         $pageUrl = $url;
1560                                                         continue;
1561                                                 }
1562
1563                                                 $href = JsonLD::fetchElement($url, 'as:href', '@id');
1564                                                 $mediaType = JsonLD::fetchElement($url, 'as:mediaType', '@value');
1565                                                 if (Strings::startsWith($mediaType, 'image')) {
1566                                                         $pageImage = $href;
1567                                                 } else {
1568                                                         $pageUrl = $href;
1569                                                 }
1570                                         }
1571
1572                                         $attachlist[] = [
1573                                                 'type'  => 'link',
1574                                                 'title' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1575                                                 'desc'  => JsonLD::fetchElement($attachment, 'as:summary', '@value'),
1576                                                 'url'   => $pageUrl,
1577                                                 'image' => $pageImage,
1578                                         ];
1579                                         break;
1580                                 case 'as:Image':
1581                                         $mediaType = JsonLD::fetchElement($attachment, 'as:mediaType', '@value');
1582                                         $imageFullUrl = JsonLD::fetchElement($attachment, 'as:url', '@id');
1583                                         $imagePreviewUrl = null;
1584                                         // Multiple URLs?
1585                                         if (!$imageFullUrl && ($urls = JsonLD::fetchElementArray($attachment, 'as:url'))) {
1586                                                 $imageVariants = [];
1587                                                 $previewVariants = [];
1588                                                 foreach ($urls as $url) {
1589                                                         // Scalar URL, no discrimination possible
1590                                                         if (is_string($url)) {
1591                                                                 $imageFullUrl = $url;
1592                                                                 continue;
1593                                                         }
1594
1595                                                         // Not sure what to do with a different Link media type than the base Image, we skip
1596                                                         if ($mediaType != JsonLD::fetchElement($url, 'as:mediaType', '@value')) {
1597                                                                 continue;
1598                                                         }
1599
1600                                                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1601
1602                                                         // Default URL choice if no discriminating width is provided
1603                                                         $imageFullUrl = $href ?? $imageFullUrl;
1604
1605                                                         $width = intval(JsonLD::fetchElement($url, 'as:width', '@value') ?? 1);
1606
1607                                                         if ($href && $width) {
1608                                                                 $imageVariants[$width] = $href;
1609                                                                 // 632 is the ideal width for full screen frio posts, we compute the absolute distance to it
1610                                                                 $previewVariants[abs(632 - $width)] = $href;
1611                                                         }
1612                                                 }
1613
1614                                                 if ($imageVariants) {
1615                                                         // Taking the maximum size image
1616                                                         ksort($imageVariants);
1617                                                         $imageFullUrl = array_pop($imageVariants);
1618
1619                                                         // Taking the minimum number distance to the target distance
1620                                                         ksort($previewVariants);
1621                                                         $imagePreviewUrl = array_shift($previewVariants);
1622                                                 }
1623
1624                                                 unset($imageVariants);
1625                                                 unset($previewVariants);
1626                                         }
1627
1628                                         $attachlist[] = [
1629                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1630                                                 'mediaType' => $mediaType,
1631                                                 'name'  => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1632                                                 'url'   => $imageFullUrl,
1633                                                 'image' => $imagePreviewUrl !== $imageFullUrl ? $imagePreviewUrl : null,
1634                                         ];
1635                                         break;
1636                                 default:
1637                                         $attachlist[] = [
1638                                                 'type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
1639                                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType', '@value'),
1640                                                 'name' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
1641                                                 'url' => JsonLD::fetchElement($attachment, 'as:url', '@id'),
1642                                                 'height' => JsonLD::fetchElement($attachment, 'as:height', '@value'),
1643                                                 'width' => JsonLD::fetchElement($attachment, 'as:width', '@value'),
1644                                                 'image' => JsonLD::fetchElement($attachment, 'as:image', '@id')
1645                                         ];
1646                         }
1647                 }
1648
1649                 return $attachlist;
1650         }
1651
1652         /**
1653          * Convert questions from JSON-LD format into a simplified format
1654          *
1655          * @param array $object
1656          *
1657          * @return array Questions in a simplified format
1658          */
1659         private static function processQuestion(array $object): array
1660         {
1661                 $question = [];
1662
1663                 if (!empty($object['as:oneOf'])) {
1664                         $question['multiple'] = false;
1665                         $options = JsonLD::fetchElementArray($object, 'as:oneOf') ?? [];
1666                 } elseif (!empty($object['as:anyOf'])) {
1667                         $question['multiple'] = true;
1668                         $options = JsonLD::fetchElementArray($object, 'as:anyOf') ?? [];
1669                 } else {
1670                         return [];
1671                 }
1672
1673                 $closed = JsonLD::fetchElement($object, 'as:closed', '@value');
1674                 if (!empty($closed)) {
1675                         $question['end-time'] = $closed;
1676                 } else {
1677                         $question['end-time'] = JsonLD::fetchElement($object, 'as:endTime', '@value');
1678                 }
1679
1680                 $question['voters']  = (int)JsonLD::fetchElement($object, 'toot:votersCount', '@value');
1681                 $question['options'] = [];
1682
1683                 $voters = 0;
1684
1685                 foreach ($options as $option) {
1686                         if (JsonLD::fetchElement($option, '@type') != 'as:Note') {
1687                                 continue;
1688                         }
1689
1690                         $name = JsonLD::fetchElement($option, 'as:name', '@value');
1691
1692                         if (empty($option['as:replies'])) {
1693                                 continue;
1694                         }
1695
1696                         $replies = JsonLD::fetchElement($option['as:replies'], 'as:totalItems', '@value');
1697
1698                         $question['options'][] = ['name' => $name, 'replies' => $replies];
1699
1700                         $voters += (int)$replies;
1701                 }
1702
1703                 // For single choice question we can count the number of voters if not provided (like with Misskey)
1704                 if (empty($question['voters']) && !$question['multiple']) {
1705                         $question['voters'] = $voters;
1706                 }
1707
1708                 return $question;
1709         }
1710
1711         /**
1712          * Fetch the original source or content with the "language" Markdown or HTML
1713          *
1714          * @param array $object
1715          * @param array $object_data
1716          *
1717          * @return array Object data (?)
1718          * @throws \Exception
1719          */
1720         private static function getSource(array $object, array $object_data): array
1721         {
1722                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/bbcode');
1723                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1724                 if (!empty($object_data['source'])) {
1725                         return $object_data;
1726                 }
1727
1728                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/markdown');
1729                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1730                 if (!empty($object_data['source'])) {
1731                         $object_data['source'] = Markdown::toBBCode($object_data['source']);
1732                         return $object_data;
1733                 }
1734
1735                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/html');
1736                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
1737                 if (!empty($object_data['source'])) {
1738                         $object_data['source'] = HTML::toBBCode($object_data['source']);
1739                         return $object_data;
1740                 }
1741
1742                 return $object_data;
1743         }
1744
1745         /**
1746          * Extracts a potential alternate URL from a list of additional URL elements
1747          *
1748          * @param array $urls
1749          * @return string
1750          */
1751         private static function extractAlternateUrl(array $urls): string
1752         {
1753                 $alternateUrl = '';
1754                 foreach ($urls as $key => $url) {
1755                         // Not a list but a single URL element
1756                         if (!is_numeric($key)) {
1757                                 continue;
1758                         }
1759
1760                         if (empty($url['@type']) || ($url['@type'] != 'as:Link')) {
1761                                 continue;
1762                         }
1763
1764                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1765                         if (empty($href)) {
1766                                 continue;
1767                         }
1768
1769                         $mediatype = JsonLD::fetchElement($url, 'as:mediaType');
1770                         if (empty($mediatype)) {
1771                                 continue;
1772                         }
1773
1774                         if ($mediatype == 'text/html') {
1775                                 $alternateUrl = $href;
1776                         }
1777                 }
1778
1779                 return $alternateUrl;
1780         }
1781
1782         /**
1783          * Check if the "as:url" element is an array with multiple links
1784          * This is the case with audio and video posts.
1785          * Then the links are added as attachments
1786          *
1787          * @param array $urls The object URL list
1788          * @return array an array of attachments
1789          */
1790         private static function processAttachmentUrls(array $urls): array
1791         {
1792                 $attachments = [];
1793                 foreach ($urls as $key => $url) {
1794                         // Not a list but a single URL element
1795                         if (!is_numeric($key)) {
1796                                 continue;
1797                         }
1798
1799                         if (empty($url['@type']) || ($url['@type'] != 'as:Link')) {
1800                                 continue;
1801                         }
1802
1803                         $href = JsonLD::fetchElement($url, 'as:href', '@id');
1804                         if (empty($href)) {
1805                                 continue;
1806                         }
1807
1808                         $mediatype = JsonLD::fetchElement($url, 'as:mediaType');
1809                         if (empty($mediatype)) {
1810                                 continue;
1811                         }
1812
1813                         $filetype = strtolower(substr($mediatype, 0, strpos($mediatype, '/')));
1814
1815                         if ($filetype == 'audio') {
1816                                 $attachments[] = ['type' => $filetype, 'mediaType' => $mediatype, 'url' => $href, 'height' => null, 'size' => null, 'name' => ''];
1817                         } elseif ($filetype == 'video') {
1818                                 $height = (int)JsonLD::fetchElement($url, 'as:height', '@value');
1819                                 // PeerTube audio-only track
1820                                 if ($height === 0) {
1821                                         continue;
1822                                 }
1823
1824                                 $size = (int)JsonLD::fetchElement($url, 'pt:size', '@value');
1825                                 $attachments[] = ['type' => $filetype, 'mediaType' => $mediatype, 'url' => $href, 'height' => $height, 'size' => $size, 'name' => ''];
1826                         } elseif (in_array($mediatype, ['application/x-bittorrent', 'application/x-bittorrent;x-scheme-handler/magnet'])) {
1827                                 $height = (int)JsonLD::fetchElement($url, 'as:height', '@value');
1828
1829                                 // For Torrent links we always store the highest resolution
1830                                 if (!empty($attachments[$mediatype]['height']) && ($height < $attachments[$mediatype]['height'])) {
1831                                         continue;
1832                                 }
1833
1834                                 $attachments[$mediatype] = ['type' => $mediatype, 'mediaType' => $mediatype, 'url' => $href, 'height' => $height, 'size' => null, 'name' => ''];
1835                         } elseif ($mediatype == 'application/x-mpegURL') {
1836                                 // PeerTube exception, actual video link is in the tags of this URL element
1837                                 $attachments = array_merge($attachments, self::processAttachmentUrls($url['as:tag']));
1838                         }
1839                 }
1840
1841                 return array_values($attachments);
1842         }
1843
1844         /**
1845          * Fetches data from the object part of an activity
1846          *
1847          * @param array $object
1848          *
1849          * @return array|bool Object data or FALSE if $object does not contain @id element
1850          * @throws \Exception
1851          */
1852         private static function processObject(array $object)
1853         {
1854                 if (!JsonLD::fetchElement($object, '@id')) {
1855                         return false;
1856                 }
1857
1858                 $object_data = self::getObjectDataFromActivity($object);
1859
1860                 $receiverdata = self::getReceivers($object, $object_data['actor'] ?? '', $object_data['tags'], true, false);
1861                 $receivers = $reception_types = [];
1862                 foreach ($receiverdata as $key => $data) {
1863                         $receivers[$key] = $data['uid'];
1864                         $reception_types[$data['uid']] = $data['type'] ?? 0;
1865                 }
1866
1867                 $object_data['receiver_urls']  = self::getReceiverURL($object);
1868                 $object_data['receiver']       = $receivers;
1869                 $object_data['reception_type'] = $reception_types;
1870
1871                 $object_data['unlisted'] = in_array(-1, $object_data['receiver']);
1872                 unset($object_data['receiver'][-1]);
1873                 unset($object_data['reception_type'][-1]);
1874
1875                 return $object_data;
1876         }
1877
1878         /**
1879          * Create an object data array from a given activity
1880          *
1881          * @param array $object
1882          *
1883          * @return array Object data
1884          */
1885         public static function getObjectDataFromActivity(array $object): array
1886         {
1887                 $object_data = [];
1888                 $object_data['object_type'] = JsonLD::fetchElement($object, '@type');
1889                 $object_data['id'] = JsonLD::fetchElement($object, '@id');
1890                 $object_data['reply-to-id'] = JsonLD::fetchElement($object, 'as:inReplyTo', '@id');
1891
1892                 // An empty "id" field is translated to "./" by the compactor, so we have to check for this content
1893                 if (empty($object_data['reply-to-id']) || ($object_data['reply-to-id'] == './')) {
1894                         $object_data['reply-to-id'] = $object_data['id'];
1895
1896                         // On activities the "reply to" is the id of the object it refers to
1897                         if (in_array($object_data['object_type'], array_merge(self::ACTIVITY_TYPES, ['as:Announce']))) {
1898                                 $object_id = JsonLD::fetchElement($object, 'as:object', '@id');
1899                                 if (!empty($object_id)) {
1900                                         $object_data['reply-to-id'] = $object_id;
1901                                 }
1902                         }
1903                 } else {
1904                         // Some systems (e.g. GNU Social) don't reply to the "id" field but the "uri" field.
1905                         $replyToId = Item::getURIByLink($object_data['reply-to-id']);
1906                         if (!empty($replyToId) && ($object_data['reply-to-id'] != $replyToId)) {
1907                                 Logger::notice('Fix wrong reply-to', ['received' => $object_data['reply-to-id'], 'correct' => $replyToId]);
1908                                 $object_data['reply-to-id'] = $replyToId;
1909                         }
1910                 }
1911
1912                 $object_data['published'] = JsonLD::fetchElement($object, 'as:published', '@value');
1913                 $object_data['updated'] = JsonLD::fetchElement($object, 'as:updated', '@value');
1914
1915                 if (empty($object_data['updated'])) {
1916                         $object_data['updated'] = $object_data['published'];
1917                 }
1918
1919                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
1920                         $object_data['published'] = $object_data['updated'];
1921                 }
1922
1923                 $actor = JsonLD::fetchElement($object, 'as:attributedTo', '@id');
1924                 if (empty($actor)) {
1925                         $actor = JsonLD::fetchElement($object, 'as:actor', '@id');
1926                 }
1927
1928                 $location = JsonLD::fetchElement($object, 'as:location', 'as:name', '@type', 'as:Place');
1929                 $location = JsonLD::fetchElement($location, 'location', '@value');
1930                 if ($location) {
1931                         // Some AP software allow formatted text in post location, so we run all the text converters we have to boil
1932                         // down to HTML and then finally format to plaintext.
1933                         $location = Markdown::convert($location);
1934                         $location = BBCode::toPlaintext($location);
1935                 }
1936
1937                 $object_data['sc:identifier'] = JsonLD::fetchElement($object, 'sc:identifier', '@value');
1938                 $object_data['diaspora:guid'] = JsonLD::fetchElement($object, 'diaspora:guid', '@value');
1939                 $object_data['diaspora:comment'] = JsonLD::fetchElement($object, 'diaspora:comment', '@value');
1940                 $object_data['diaspora:like'] = JsonLD::fetchElement($object, 'diaspora:like', '@value');
1941                 $object_data['actor'] = $object_data['author'] = $actor;
1942                 $element = JsonLD::fetchElement($object, 'as:context', '@id');
1943                 $object_data['context'] = $element != './' ? $element : null;
1944                 $element = JsonLD::fetchElement($object, 'ostatus:conversation', '@id');
1945                 $object_data['conversation'] = $element != './' ? $element : null;
1946                 $object_data['sensitive'] = JsonLD::fetchElement($object, 'as:sensitive');
1947                 $object_data['name'] = JsonLD::fetchElement($object, 'as:name', '@value');
1948                 $object_data['summary'] = JsonLD::fetchElement($object, 'as:summary', '@value');
1949                 $object_data['content'] = JsonLD::fetchElement($object, 'as:content', '@value');
1950                 $object_data['mediatype'] = JsonLD::fetchElement($object, 'as:mediaType', '@value');
1951                 $object_data = self::getSource($object, $object_data);
1952                 $object_data['start-time'] = JsonLD::fetchElement($object, 'as:startTime', '@value');
1953                 $object_data['end-time'] = JsonLD::fetchElement($object, 'as:endTime', '@value');
1954                 $object_data['location'] = $location;
1955                 $object_data['latitude'] = JsonLD::fetchElement($object, 'as:location', 'as:latitude', '@type', 'as:Place');
1956                 $object_data['latitude'] = JsonLD::fetchElement($object_data, 'latitude', '@value');
1957                 $object_data['longitude'] = JsonLD::fetchElement($object, 'as:location', 'as:longitude', '@type', 'as:Place');
1958                 $object_data['longitude'] = JsonLD::fetchElement($object_data, 'longitude', '@value');
1959                 $object_data['attachments'] = self::processAttachments(JsonLD::fetchElementArray($object, 'as:attachment') ?? []);
1960                 $object_data['tags'] = self::processTags(JsonLD::fetchElementArray($object, 'as:tag') ?? []);
1961                 $object_data['emojis'] = self::processEmojis(JsonLD::fetchElementArray($object, 'as:tag', null, '@type', 'toot:Emoji') ?? []);
1962                 $object_data['languages'] = self::processLanguages(JsonLD::fetchElementArray($object, 'sc:inLanguage') ?? []);
1963                 $object_data['generator'] = JsonLD::fetchElement($object, 'as:generator', 'as:name', '@type', 'as:Application');
1964                 $object_data['generator'] = JsonLD::fetchElement($object_data, 'generator', '@value');
1965                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'as:url', '@id');
1966
1967                 // Special treatment for Hubzilla links
1968                 if (is_array($object_data['alternate-url'])) {
1969                         $object_data['alternate-url'] = JsonLD::fetchElement($object_data['alternate-url'], 'as:href', '@id');
1970
1971                         if (!is_string($object_data['alternate-url'])) {
1972                                 $object_data['alternate-url'] = JsonLD::fetchElement($object['as:url'], 'as:href', '@id');
1973                         }
1974                 }
1975
1976                 if (!empty($object_data['alternate-url']) && !Network::isValidHttpUrl($object_data['alternate-url'])) {
1977                         $object_data['alternate-url'] = null;
1978                 }
1979
1980                 if (in_array($object_data['object_type'], ['as:Audio', 'as:Video'])) {
1981                         $object_data['alternate-url'] = self::extractAlternateUrl($object['as:url'] ?? []) ?: $object_data['alternate-url'];
1982                         $object_data['attachments'] = array_merge($object_data['attachments'], self::processAttachmentUrls($object['as:url'] ?? []));
1983                 }
1984
1985                 // Support for quoted posts (Pleroma, Fedibird and Misskey)
1986                 $object_data['quote-url'] = JsonLD::fetchElement($object, 'as:quoteUrl', '@value');
1987                 if (empty($object_data['quote-url'])) {
1988                         $object_data['quote-url'] = JsonLD::fetchElement($object, 'fedibird:quoteUri', '@value');
1989                 }
1990                 if (empty($object_data['quote-url'])) {
1991                         $object_data['quote-url'] = JsonLD::fetchElement($object, 'misskey:_misskey_quote', '@value');
1992                 }
1993
1994                 // Misskey adds some data to the standard "content" value for quoted posts for backwards compatibility.
1995                 // Their own "_misskey_content" value does then contain the content without this extra data.
1996                 if (!empty($object_data['quote-url'])) {
1997                         $misskey_content = JsonLD::fetchElement($object, 'misskey:_misskey_content', '@value');
1998                         if (!empty($misskey_content)) {
1999                                 $object_data['content'] = $misskey_content;
2000                         }
2001                 }
2002
2003                 // For page types we expect that the alternate url posts to some page.
2004                 // So we add this to the attachments if it differs from the id.
2005                 // Currently only Lemmy is using the page type.
2006                 if (($object_data['object_type'] == 'as:Page') && !empty($object_data['alternate-url']) && !Strings::compareLink($object_data['alternate-url'], $object_data['id'])) {
2007                         $object_data['attachments'][] = ['url' => $object_data['alternate-url']];
2008                         $object_data['alternate-url'] = null;
2009                 }
2010
2011                 if ($object_data['object_type'] == 'as:Question') {
2012                         $object_data['question'] = self::processQuestion($object);
2013                 }
2014
2015                 return $object_data;
2016         }
2017
2018         /**
2019          * Add an object id to the list of arrived activities
2020          *
2021          * @param string $id
2022          *
2023          * @return void
2024          */
2025         private static function addArrivedId(string $id)
2026         {
2027                 DBA::delete('arrived-activity', ["`received` < ?", DateTimeFormat::utc('now - 5 minutes')]);
2028                 DBA::insert('arrived-activity', ['object-id' => $id, 'received' => DateTimeFormat::utcNow()], Database::INSERT_IGNORE);
2029         }
2030
2031         /**
2032          * Checks if the given object already arrived before
2033          *
2034          * @param string $id
2035          *
2036          * @return boolean
2037          */
2038         private static function hasArrived(string $id): bool
2039         {
2040                 return DBA::exists('arrived-activity', ['object-id' => $id]);
2041         }
2042 }