src/Protocol/ActivityPub/Receiver.php

   1 <?php
   2 /**
   3  * @file src/Protocol/ActivityPub/Receiver.php
   4  */
   5 namespace Friendica\Protocol\ActivityPub;
   6
   7 use Friendica\Database\DBA;
   8 use Friendica\Core\Logger;
   9 use Friendica\Core\Protocol;
  10 use Friendica\Model\Contact;
  11 use Friendica\Model\APContact;
  12 use Friendica\Model\Conversation;
  13 use Friendica\Model\Item;
  14 use Friendica\Model\User;
  15 use Friendica\Protocol\Activity;
  16 use Friendica\Protocol\ActivityPub;
  17 use Friendica\Util\DateTimeFormat;
  18 use Friendica\Util\HTTPSignature;
  19 use Friendica\Util\JsonLD;
  20 use Friendica\Util\LDSignature;
  21 use Friendica\Util\Strings;
  22
  23 /**
  24  * @brief ActivityPub Receiver Protocol class
  25  *
  26  * To-Do:
  27  * - Undo Announce
  28  *
  29  * Check what this is meant to do:
  30  * - Add
  31  * - Block
  32  * - Flag
  33  * - Remove
  34  * - Undo Block
  35  */
  36 class Receiver
  37 {
  38         const PUBLIC_COLLECTION = 'as:Public';
  39         const ACCOUNT_TYPES = ['as:Person', 'as:Organization', 'as:Service', 'as:Group', 'as:Application'];
  40         const CONTENT_TYPES = ['as:Note', 'as:Article', 'as:Video', 'as:Image', 'as:Event'];
  41         const ACTIVITY_TYPES = ['as:Like', 'as:Dislike', 'as:Accept', 'as:Reject', 'as:TentativeAccept'];
  42
  43         /**
  44          * Checks if the web request is done for the AP protocol
  45          *
  46          * @return bool is it AP?
  47          */
  48         public static function isRequest()
  49         {
  50                 return stristr($_SERVER['HTTP_ACCEPT'] ?? '', 'application/activity+json') ||
  51                         stristr($_SERVER['HTTP_ACCEPT'] ?? '', 'application/ld+json');
  52         }
  53
  54         /**
  55          * Checks incoming message from the inbox
  56          *
  57          * @param         $body
  58          * @param         $header
  59          * @param integer $uid User ID
  60          * @throws \Exception
  61          */
  62         public static function processInbox($body, $header, $uid)
  63         {
  64                 $http_signer = HTTPSignature::getSigner($body, $header);
  65                 if (empty($http_signer)) {
  66                         Logger::warning('Invalid HTTP signature, message will be discarded.');
  67                         return;
  68                 } else {
  69                         Logger::info('Valid HTTP signature', ['signer' => $http_signer]);
  70                 }
  71
  72                 $activity = json_decode($body, true);
  73
  74                 if (empty($activity)) {
  75                         Logger::warning('Invalid body.');
  76                         return;
  77                 }
  78
  79                 $ldactivity = JsonLD::compact($activity);
  80
  81                 $actor = JsonLD::fetchElement($ldactivity, 'as:actor', '@id');
  82
  83                 Logger::info('Message for user ' . $uid . ' is from actor ' . $actor);
  84
  85                 if (LDSignature::isSigned($activity)) {
  86                         $ld_signer = LDSignature::getSigner($activity);
  87                         if (empty($ld_signer)) {
  88                                 Logger::log('Invalid JSON-LD signature from ' . $actor, Logger::DEBUG);
  89                         }
  90                         if (!empty($ld_signer && ($actor == $http_signer))) {
  91                                 Logger::log('The HTTP and the JSON-LD signature belong to ' . $ld_signer, Logger::DEBUG);
  92                                 $trust_source = true;
  93                         } elseif (!empty($ld_signer)) {
  94                                 Logger::log('JSON-LD signature is signed by ' . $ld_signer, Logger::DEBUG);
  95                                 $trust_source = true;
  96                         } elseif ($actor == $http_signer) {
  97                                 Logger::log('Bad JSON-LD signature, but HTTP signer fits the actor.', Logger::DEBUG);
  98                                 $trust_source = true;
  99                         } else {
 100                                 Logger::log('Invalid JSON-LD signature and the HTTP signer is different.', Logger::DEBUG);
 101                                 $trust_source = false;
 102                         }
 103                 } elseif ($actor == $http_signer) {
 104                         Logger::log('Trusting post without JSON-LD signature, The actor fits the HTTP signer.', Logger::DEBUG);
 105                         $trust_source = true;
 106                 } else {
 107                         Logger::log('No JSON-LD signature, different actor.', Logger::DEBUG);
 108                         $trust_source = false;
 109                 }
 110
 111                 self::processActivity($ldactivity, $body, $uid, $trust_source);
 112         }
 113
 114         /**
 115          * Fetches the object type for a given object id
 116          *
 117          * @param array   $activity
 118          * @param string  $object_id Object ID of the the provided object
 119          * @param integer $uid       User ID
 120          *
 121          * @return string with object type
 122          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 123          * @throws \ImagickException
 124          */
 125         private static function fetchObjectType($activity, $object_id, $uid = 0)
 126         {
 127                 if (!empty($activity['as:object'])) {
 128                         $object_type = JsonLD::fetchElement($activity['as:object'], '@type');
 129                         if (!empty($object_type)) {
 130                                 return $object_type;
 131                         }
 132                 }
 133
 134                 if (Item::exists(['uri' => $object_id, 'gravity' => [GRAVITY_PARENT, GRAVITY_COMMENT]])) {
 135                         // We just assume "note" since it doesn't make a difference for the further processing
 136                         return 'as:Note';
 137                 }
 138
 139                 $profile = APContact::getByURL($object_id);
 140                 if (!empty($profile['type'])) {
 141                         return 'as:' . $profile['type'];
 142                 }
 143
 144                 $data = ActivityPub::fetchContent($object_id, $uid);
 145                 if (!empty($data)) {
 146                         $object = JsonLD::compact($data);
 147                         $type = JsonLD::fetchElement($object, '@type');
 148                         if (!empty($type)) {
 149                                 return $type;
 150                         }
 151                 }
 152
 153                 return null;
 154         }
 155
 156         /**
 157          * Prepare the object array
 158          *
 159          * @param array   $activity
 160          * @param integer $uid User ID
 161          * @param         $trust_source
 162          *
 163          * @return array with object data
 164          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 165          * @throws \ImagickException
 166          */
 167         private static function prepareObjectData($activity, $uid, &$trust_source)
 168         {
 169                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 170                 if (empty($actor)) {
 171                         Logger::log('Empty actor', Logger::DEBUG);
 172                         return [];
 173                 }
 174
 175                 $type = JsonLD::fetchElement($activity, '@type');
 176
 177                 // Fetch all receivers from to, cc, bto and bcc
 178                 $receivers = self::getReceivers($activity, $actor);
 179
 180                 // When it is a delivery to a personal inbox we add that user to the receivers
 181                 if (!empty($uid)) {
 182                         $additional = ['uid:' . $uid => $uid];
 183                         $receivers = array_merge($receivers, $additional);
 184                 } else {
 185                         // We possibly need some user to fetch private content,
 186                         // so we fetch the first out ot the list.
 187                         $uid = self::getFirstUserFromReceivers($receivers);
 188                 }
 189
 190                 Logger::log('Receivers: ' . $uid . ' - ' . json_encode($receivers), Logger::DEBUG);
 191
 192                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 193                 if (empty($object_id)) {
 194                         Logger::log('No object found', Logger::DEBUG);
 195                         return [];
 196                 }
 197
 198                 if (!is_string($object_id)) {
 199                         Logger::info('Invalid object id', ['object' => $object_id]);
 200                         return [];
 201                 }
 202
 203                 $object_type = self::fetchObjectType($activity, $object_id, $uid);
 204
 205                 // Fetch the content only on activities where this matters
 206                 if (in_array($type, ['as:Create', 'as:Update', 'as:Announce'])) {
 207                         if ($type == 'as:Announce') {
 208                                 $trust_source = false;
 209                         }
 210                         $object_data = self::fetchObject($object_id, $activity['as:object'], $trust_source, $uid);
 211                         if (empty($object_data)) {
 212                                 Logger::log("Object data couldn't be processed", Logger::DEBUG);
 213                                 return [];
 214                         }
 215                         $object_data['object_id'] = $object_id;
 216
 217                         // Test if it is an answer to a mail
 218                         if (DBA::exists('mail', ['uri' => $object_data['reply-to-id']])) {
 219                                 $object_data['directmessage'] = true;
 220                         } else {
 221                                 $object_data['directmessage'] = JsonLD::fetchElement($activity, 'litepub:directMessage');
 222                         }
 223
 224                         // We had been able to retrieve the object data - so we can trust the source
 225                         $trust_source = true;
 226                 } elseif (in_array($type, array_merge(self::ACTIVITY_TYPES, ['as:Follow'])) && in_array($object_type, self::CONTENT_TYPES)) {
 227                         // Create a mostly empty array out of the activity data (instead of the object).
 228                         // This way we later don't have to check for the existence of ech individual array element.
 229                         $object_data = self::processObject($activity);
 230                         $object_data['name'] = $type;
 231                         $object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 232                         $object_data['object_id'] = $object_id;
 233                         $object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
 234                 } elseif (in_array($type, ['as:Add'])) {
 235                         $object_data = [];
 236                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 237                         $object_data['target_id'] = JsonLD::fetchElement($activity, 'as:target', '@id');
 238                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 239                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 240                         $object_data['object_content'] = JsonLD::fetchElement($activity['as:object'], 'as:content', '@type');
 241                 } else {
 242                         $object_data = [];
 243                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 244                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 245                         $object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor', '@id');
 246                         $object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
 247                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 248
 249                         // An Undo is done on the object of an object, so we need that type as well
 250                         if ($type == 'as:Undo') {
 251                                 $object_data['object_object_type'] = self::fetchObjectType([], $object_data['object_object'], $uid);
 252                         }
 253                 }
 254
 255                 $object_data = self::addActivityFields($object_data, $activity);
 256
 257                 if (empty($object_data['object_type'])) {
 258                         $object_data['object_type'] = $object_type;
 259                 }
 260
 261                 $object_data['type'] = $type;
 262                 $object_data['actor'] = $actor;
 263                 $object_data['item_receiver'] = $receivers;
 264                 $object_data['receiver'] = array_merge($object_data['receiver'] ?? [], $receivers);
 265
 266                 Logger::log('Processing ' . $object_data['type'] . ' ' . $object_data['object_type'] . ' ' . $object_data['id'], Logger::DEBUG);
 267
 268                 return $object_data;
 269         }
 270
 271         /**
 272          * Fetches the first user id from the receiver array
 273          *
 274          * @param array $receivers Array with receivers
 275          * @return integer user id;
 276          */
 277         public static function getFirstUserFromReceivers($receivers)
 278         {
 279                 foreach ($receivers as $receiver) {
 280                         if (!empty($receiver)) {
 281                                 return $receiver;
 282                         }
 283                 }
 284                 return 0;
 285         }
 286
 287         /**
 288          * Store the unprocessed data into the conversation table
 289          * This has to be done outside the regular function,
 290          * since we store everything - not only item posts.
 291          *
 292          * @param array  $activity Array with activity data
 293          * @param string $body     The raw message
 294          * @throws \Exception
 295          */
 296         private static function storeConversation($activity, $body)
 297         {
 298                 if (empty($body) || empty($activity['id'])) {
 299                         return;
 300                 }
 301
 302                 $conversation = [
 303                         'protocol' => Conversation::PARCEL_ACTIVITYPUB,
 304                         'item-uri' => $activity['id'],
 305                         'reply-to-uri' => $activity['reply-to-id'] ?? '',
 306                         'conversation-href' => $activity['context'] ?? '',
 307                         'conversation-uri' => $activity['conversation'] ?? '',
 308                         'source' => $body,
 309                         'received' => DateTimeFormat::utcNow()];
 310
 311                 DBA::insert('conversation', $conversation, true);
 312         }
 313
 314         /**
 315          * Processes the activity object
 316          *
 317          * @param array   $activity     Array with activity data
 318          * @param string  $body
 319          * @param integer $uid          User ID
 320          * @param boolean $trust_source Do we trust the source?
 321          * @throws \Exception
 322          */
 323         public static function processActivity($activity, $body = '', $uid = null, $trust_source = false)
 324         {
 325                 $type = JsonLD::fetchElement($activity, '@type');
 326                 if (!$type) {
 327                         Logger::log('Empty type', Logger::DEBUG);
 328                         return;
 329                 }
 330
 331                 if (!JsonLD::fetchElement($activity, 'as:object', '@id')) {
 332                         Logger::log('Empty object', Logger::DEBUG);
 333                         return;
 334                 }
 335
 336                 if (!JsonLD::fetchElement($activity, 'as:actor', '@id')) {
 337                         Logger::log('Empty actor', Logger::DEBUG);
 338                         return;
 339
 340                 }
 341
 342                 // Don't trust the source if "actor" differs from "attributedTo". The content could be forged.
 343                 if ($trust_source && ($type == 'as:Create') && is_array($activity['as:object'])) {
 344                         $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 345                         $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
 346                         $trust_source = ($actor == $attributed_to);
 347                         if (!$trust_source) {
 348                                 Logger::log('Not trusting actor: ' . $actor . '. It differs from attributedTo: ' . $attributed_to, Logger::DEBUG);
 349                         }
 350                 }
 351
 352                 // $trust_source is called by reference and is set to true if the content was retrieved successfully
 353                 $object_data = self::prepareObjectData($activity, $uid, $trust_source);
 354                 if (empty($object_data)) {
 355                         Logger::log('No object data found', Logger::DEBUG);
 356                         return;
 357                 }
 358
 359                 if (!$trust_source) {
 360                         Logger::log('No trust for activity type "' . $type . '", so we quit now.', Logger::DEBUG);
 361                         return;
 362                 }
 363
 364                 // Only store content related stuff - and no announces, since they possibly overwrite the original content
 365                 if (in_array($object_data['object_type'], self::CONTENT_TYPES) && ($type != 'as:Announce')) {
 366                         self::storeConversation($object_data, $body);
 367                 }
 368
 369                 // Internal flag for thread completion. See Processor.php
 370                 if (!empty($activity['thread-completion'])) {
 371                         $object_data['thread-completion'] = $activity['thread-completion'];
 372                 }
 373
 374                 switch ($type) {
 375                         case 'as:Create':
 376                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 377                                         ActivityPub\Processor::createItem($object_data);
 378                                 }
 379                                 break;
 380
 381                         case 'as:Add':
 382                                 if ($object_data['object_type'] == 'as:tag') {
 383                                         ActivityPub\Processor::addTag($object_data);
 384                                 }
 385                                 break;
 386
 387                         case 'as:Announce':
 388                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 389                                         $profile = APContact::getByURL($object_data['actor']);
 390                                         // Reshared posts from persons appear as summary at the bottom
 391                                         // If this isn't set, then a single reshare appears on top. This is used for groups.
 392                                         $object_data['thread-completion'] = ($profile['type'] != 'Group');
 393
 394                                         ActivityPub\Processor::createItem($object_data);
 395
 396                                         // Add the bottom reshare information only for persons
 397                                         if ($profile['type'] != 'Group') {
 398                                                 $announce_object_data = self::processObject($activity);
 399                                                 $announce_object_data['name'] = $type;
 400                                                 $announce_object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 401                                                 $announce_object_data['object_id'] = $object_data['object_id'];
 402                                                 $announce_object_data['object_type'] = $object_data['object_type'];
 403
 404                                                 ActivityPub\Processor::createActivity($announce_object_data, Activity::ANNOUNCE);
 405                                         }
 406                                 }
 407                                 break;
 408
 409                         case 'as:Like':
 410                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 411                                         ActivityPub\Processor::createActivity($object_data, Activity::LIKE);
 412                                 }
 413                                 break;
 414
 415                         case 'as:Dislike':
 416                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 417                                         ActivityPub\Processor::createActivity($object_data, Activity::DISLIKE);
 418                                 }
 419                                 break;
 420
 421                         case 'as:TentativeAccept':
 422                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 423                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDMAYBE);
 424                                 }
 425                                 break;
 426
 427                         case 'as:Update':
 428                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 429                                         ActivityPub\Processor::updateItem($object_data);
 430                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 431                                         ActivityPub\Processor::updatePerson($object_data);
 432                                 }
 433                                 break;
 434
 435                         case 'as:Delete':
 436                                 if ($object_data['object_type'] == 'as:Tombstone') {
 437                                         ActivityPub\Processor::deleteItem($object_data);
 438                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 439                                         ActivityPub\Processor::deletePerson($object_data);
 440                                 }
 441                                 break;
 442
 443                         case 'as:Follow':
 444                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 445                                         ActivityPub\Processor::followUser($object_data);
 446                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 447                                         $object_data['reply-to-id'] = $object_data['object_id'];
 448                                         ActivityPub\Processor::createActivity($object_data, Activity::FOLLOW);
 449                                 }
 450                                 break;
 451
 452                         case 'as:Accept':
 453                                 if ($object_data['object_type'] == 'as:Follow') {
 454                                         ActivityPub\Processor::acceptFollowUser($object_data);
 455                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 456                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTEND);
 457                                 }
 458                                 break;
 459
 460                         case 'as:Reject':
 461                                 if ($object_data['object_type'] == 'as:Follow') {
 462                                         ActivityPub\Processor::rejectFollowUser($object_data);
 463                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 464                                         ActivityPub\Processor::createActivity($object_data, Activity::ATTENDNO);
 465                                 }
 466                                 break;
 467
 468                         case 'as:Undo':
 469                                 if (($object_data['object_type'] == 'as:Follow') &&
 470                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 471                                         ActivityPub\Processor::undoFollowUser($object_data);
 472                                 } elseif (($object_data['object_type'] == 'as:Accept') &&
 473                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 474                                         ActivityPub\Processor::rejectFollowUser($object_data);
 475                                 } elseif (in_array($object_data['object_type'], self::ACTIVITY_TYPES) &&
 476                                         in_array($object_data['object_object_type'], self::CONTENT_TYPES)) {
 477                                         ActivityPub\Processor::undoActivity($object_data);
 478                                 }
 479                                 break;
 480
 481                         default:
 482                                 Logger::log('Unknown activity: ' . $type . ' ' . $object_data['object_type'], Logger::DEBUG);
 483                                 break;
 484                 }
 485         }
 486
 487         /**
 488          * Fetch the receiver list from an activity array
 489          *
 490          * @param array  $activity
 491          * @param string $actor
 492          * @param array  $tags
 493          *
 494          * @return array with receivers (user id)
 495          * @throws \Exception
 496          */
 497         private static function getReceivers($activity, $actor, $tags = [])
 498         {
 499                 $receivers = [];
 500
 501                 // When it is an answer, we inherite the receivers from the parent
 502                 $replyto = JsonLD::fetchElement($activity, 'as:inReplyTo', '@id');
 503                 if (!empty($replyto)) {
 504                         $parents = Item::select(['uid'], ['uri' => $replyto]);
 505                         while ($parent = Item::fetch($parents)) {
 506                                 $receivers['uid:' . $parent['uid']] = $parent['uid'];
 507                         }
 508                 }
 509
 510                 if (!empty($actor)) {
 511                         $profile = APContact::getByURL($actor);
 512                         $followers = $profile['followers'] ?? '';
 513
 514                         Logger::log('Actor: ' . $actor . ' - Followers: ' . $followers, Logger::DEBUG);
 515                 } else {
 516                         Logger::log('Empty actor', Logger::DEBUG);
 517                         $followers = '';
 518                 }
 519
 520                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
 521                         $receiver_list = JsonLD::fetchElementArray($activity, $element, '@id');
 522                         if (empty($receiver_list)) {
 523                                 continue;
 524                         }
 525
 526                         foreach ($receiver_list as $receiver) {
 527                                 if ($receiver == self::PUBLIC_COLLECTION) {
 528                                         $receivers['uid:0'] = 0;
 529                                 }
 530
 531                                 if (($receiver == self::PUBLIC_COLLECTION) && !empty($actor)) {
 532                                         // This will most likely catch all OStatus connections to Mastodon
 533                                         $condition = ['alias' => [$actor, Strings::normaliseLink($actor)], 'rel' => [Contact::SHARING, Contact::FRIEND]
 534                                                 , 'archive' => false, 'pending' => false];
 535                                         $contacts = DBA::select('contact', ['uid'], $condition);
 536                                         while ($contact = DBA::fetch($contacts)) {
 537                                                 if ($contact['uid'] != 0) {
 538                                                         $receivers['uid:' . $contact['uid']] = $contact['uid'];
 539                                                 }
 540                                         }
 541                                         DBA::close($contacts);
 542                                 }
 543
 544                                 if (in_array($receiver, [$followers, self::PUBLIC_COLLECTION]) && !empty($actor)) {
 545                                         $receivers = array_merge($receivers, self::getReceiverForActor($actor, $tags));
 546                                         continue;
 547                                 }
 548
 549                                 // Fetching all directly addressed receivers
 550                                 $condition = ['self' => true, 'nurl' => Strings::normaliseLink($receiver)];
 551                                 $contact = DBA::selectFirst('contact', ['uid', 'contact-type'], $condition);
 552                                 if (!DBA::isResult($contact)) {
 553                                         continue;
 554                                 }
 555
 556                                 // Check if the potential receiver is following the actor
 557                                 // Exception: The receiver is targetted via "to" or this is a comment
 558                                 if ((($element != 'as:to') && empty($replyto)) || ($contact['contact-type'] == Contact::TYPE_COMMUNITY)) {
 559                                         $networks = Protocol::FEDERATED;
 560                                         $condition = ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
 561                                                 'network' => $networks, 'archive' => false, 'pending' => false, 'uid' => $contact['uid']];
 562
 563                                         // Forum posts are only accepted from forum contacts
 564                                         if ($contact['contact-type'] == Contact::TYPE_COMMUNITY) {
 565                                                 $condition['rel'] = [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER];
 566                                         }
 567
 568                                         if (!DBA::exists('contact', $condition)) {
 569                                                 continue;
 570                                         }
 571                                 }
 572
 573                                 $receivers['uid:' . $contact['uid']] = $contact['uid'];
 574                         }
 575                 }
 576
 577                 self::switchContacts($receivers, $actor);
 578
 579                 return $receivers;
 580         }
 581
 582         /**
 583          * Fetch the receiver list of a given actor
 584          *
 585          * @param string $actor
 586          * @param array  $tags
 587          *
 588          * @return array with receivers (user id)
 589          * @throws \Exception
 590          */
 591         public static function getReceiverForActor($actor, $tags)
 592         {
 593                 $receivers = [];
 594                 $networks = Protocol::FEDERATED;
 595                 $condition = ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER],
 596                         'network' => $networks, 'archive' => false, 'pending' => false];
 597                 $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
 598                 while ($contact = DBA::fetch($contacts)) {
 599                         if (self::isValidReceiverForActor($contact, $actor, $tags)) {
 600                                 $receivers['uid:' . $contact['uid']] = $contact['uid'];
 601                         }
 602                 }
 603                 DBA::close($contacts);
 604                 return $receivers;
 605         }
 606
 607         /**
 608          * Tests if the contact is a valid receiver for this actor
 609          *
 610          * @param array  $contact
 611          * @param string $actor
 612          * @param array  $tags
 613          *
 614          * @return bool with receivers (user id)
 615          * @throws \Exception
 616          */
 617         private static function isValidReceiverForActor($contact, $actor, $tags)
 618         {
 619                 // Public contacts are no valid receiver
 620                 if ($contact['uid'] == 0) {
 621                         return false;
 622                 }
 623
 624                 // Are we following the contact? Then this is a valid receiver
 625                 if (in_array($contact['rel'], [Contact::SHARING, Contact::FRIEND])) {
 626                         return true;
 627                 }
 628
 629                 // When the possible receiver isn't a community, then it is no valid receiver
 630                 $owner = User::getOwnerDataById($contact['uid']);
 631                 if (empty($owner) || ($owner['contact-type'] != Contact::TYPE_COMMUNITY)) {
 632                         return false;
 633                 }
 634
 635                 // Is the community account tagged?
 636                 foreach ($tags as $tag) {
 637                         if ($tag['type'] != 'Mention') {
 638                                 continue;
 639                         }
 640
 641                         if ($tag['href'] == $owner['url']) {
 642                                 return true;
 643                         }
 644                 }
 645
 646                 return false;
 647         }
 648
 649         /**
 650          * Switches existing contacts to ActivityPub
 651          *
 652          * @param integer $cid Contact ID
 653          * @param integer $uid User ID
 654          * @param string  $url Profile URL
 655          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 656          * @throws \ImagickException
 657          */
 658         public static function switchContact($cid, $uid, $url)
 659         {
 660                 if (DBA::exists('contact', ['id' => $cid, 'network' => Protocol::ACTIVITYPUB])) {
 661                         Logger::info('Contact is already ActivityPub', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
 662                         return;
 663                 }
 664
 665                 if (Contact::updateFromProbe($cid, '', true)) {
 666                         Logger::info('Update was successful', ['id' => $cid, 'uid' => $uid, 'url' => $url]);
 667                 }
 668
 669                 // Send a new follow request to be sure that the connection still exists
 670                 if (($uid != 0) && DBA::exists('contact', ['id' => $cid, 'rel' => [Contact::SHARING, Contact::FRIEND], 'network' => Protocol::ACTIVITYPUB])) {
 671                         Logger::info('Contact had been switched to ActivityPub. Sending a new follow request.', ['uid' => $uid, 'url' => $url]);
 672                         ActivityPub\Transmitter::sendActivity('Follow', $url, $uid);
 673                 }
 674         }
 675
 676         /**
 677          *
 678          *
 679          * @param $receivers
 680          * @param $actor
 681          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 682          * @throws \ImagickException
 683          */
 684         private static function switchContacts($receivers, $actor)
 685         {
 686                 if (empty($actor)) {
 687                         return;
 688                 }
 689
 690                 foreach ($receivers as $receiver) {
 691                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver, 'network' => Protocol::OSTATUS, 'nurl' => Strings::normaliseLink($actor)]);
 692                         if (DBA::isResult($contact)) {
 693                                 self::switchContact($contact['id'], $receiver, $actor);
 694                         }
 695
 696                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver, 'network' => Protocol::OSTATUS, 'alias' => [Strings::normaliseLink($actor), $actor]]);
 697                         if (DBA::isResult($contact)) {
 698                                 self::switchContact($contact['id'], $receiver, $actor);
 699                         }
 700                 }
 701         }
 702
 703         /**
 704          *
 705          *
 706          * @param       $object_data
 707          * @param array $activity
 708          *
 709          * @return mixed
 710          */
 711         private static function addActivityFields($object_data, $activity)
 712         {
 713                 if (!empty($activity['published']) && empty($object_data['published'])) {
 714                         $object_data['published'] = JsonLD::fetchElement($activity, 'as:published', '@value');
 715                 }
 716
 717                 if (!empty($activity['diaspora:guid']) && empty($object_data['diaspora:guid'])) {
 718                         $object_data['diaspora:guid'] = JsonLD::fetchElement($activity, 'diaspora:guid', '@value');
 719                 }
 720
 721                 $object_data['service'] = JsonLD::fetchElement($activity, 'as:instrument', 'as:name', '@type', 'as:Service');
 722                 $object_data['service'] = JsonLD::fetchElement($object_data, 'service', '@value');
 723
 724                 return $object_data;
 725         }
 726
 727         /**
 728          * Fetches the object data from external ressources if needed
 729          *
 730          * @param string  $object_id    Object ID of the the provided object
 731          * @param array   $object       The provided object array
 732          * @param boolean $trust_source Do we trust the provided object?
 733          * @param integer $uid          User ID for the signature that we use to fetch data
 734          *
 735          * @return array|false with trusted and valid object data
 736          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 737          * @throws \ImagickException
 738          */
 739         private static function fetchObject(string $object_id, array $object = [], bool $trust_source = false, int $uid = 0)
 740         {
 741                 // By fetching the type we check if the object is complete.
 742                 $type = JsonLD::fetchElement($object, '@type');
 743
 744                 if (!$trust_source || empty($type)) {
 745                         $data = ActivityPub::fetchContent($object_id, $uid);
 746                         if (!empty($data)) {
 747                                 $object = JsonLD::compact($data);
 748                                 Logger::log('Fetched content for ' . $object_id, Logger::DEBUG);
 749                         } else {
 750                                 Logger::log('Empty content for ' . $object_id . ', check if content is available locally.', Logger::DEBUG);
 751
 752                                 $item = Item::selectFirst([], ['uri' => $object_id]);
 753                                 if (!DBA::isResult($item)) {
 754                                         Logger::log('Object with url ' . $object_id . ' was not found locally.', Logger::DEBUG);
 755                                         return false;
 756                                 }
 757                                 Logger::log('Using already stored item for url ' . $object_id, Logger::DEBUG);
 758                                 $data = ActivityPub\Transmitter::createNote($item);
 759                                 $object = JsonLD::compact($data);
 760                         }
 761                 } else {
 762                         Logger::log('Using original object for url ' . $object_id, Logger::DEBUG);
 763                 }
 764
 765                 $type = JsonLD::fetchElement($object, '@type');
 766
 767                 if (empty($type)) {
 768                         Logger::log('Empty type', Logger::DEBUG);
 769                         return false;
 770                 }
 771
 772                 if (in_array($type, self::CONTENT_TYPES)) {
 773                         return self::processObject($object);
 774                 }
 775
 776                 if ($type == 'as:Announce') {
 777                         $object_id = JsonLD::fetchElement($object, 'object', '@id');
 778                         if (empty($object_id) || !is_string($object_id)) {
 779                                 return false;
 780                         }
 781                         return self::fetchObject($object_id, [], false, $uid);
 782                 }
 783
 784                 Logger::log('Unhandled object type: ' . $type, Logger::DEBUG);
 785                 return false;
 786         }
 787
 788         /**
 789          * Convert tags from JSON-LD format into a simplified format
 790          *
 791          * @param array $tags Tags in JSON-LD format
 792          *
 793          * @return array with tags in a simplified format
 794          */
 795         private static function processTags($tags)
 796         {
 797                 $taglist = [];
 798
 799                 if (empty($tags)) {
 800                         return [];
 801                 }
 802
 803                 foreach ($tags as $tag) {
 804                         if (empty($tag)) {
 805                                 continue;
 806                         }
 807
 808                         $element = ['type' => str_replace('as:', '', JsonLD::fetchElement($tag, '@type')),
 809                                 'href' => JsonLD::fetchElement($tag, 'as:href', '@id'),
 810                                 'name' => JsonLD::fetchElement($tag, 'as:name', '@value')];
 811
 812                         if (empty($element['type'])) {
 813                                 continue;
 814                         }
 815
 816                         $taglist[] = $element;
 817                 }
 818                 return $taglist;
 819         }
 820
 821         /**
 822          * Convert emojis from JSON-LD format into a simplified format
 823          *
 824          * @param $emojis
 825          * @return array with emojis in a simplified format
 826          */
 827         private static function processEmojis($emojis)
 828         {
 829                 $emojilist = [];
 830
 831                 if (empty($emojis)) {
 832                         return [];
 833                 }
 834
 835                 foreach ($emojis as $emoji) {
 836                         if (empty($emoji) || (JsonLD::fetchElement($emoji, '@type') != 'toot:Emoji') || empty($emoji['as:icon'])) {
 837                                 continue;
 838                         }
 839
 840                         $url = JsonLD::fetchElement($emoji['as:icon'], 'as:url', '@id');
 841                         $element = ['name' => JsonLD::fetchElement($emoji, 'as:name', '@value'),
 842                                 'href' => $url];
 843
 844                         $emojilist[] = $element;
 845                 }
 846                 return $emojilist;
 847         }
 848
 849         /**
 850          * Convert attachments from JSON-LD format into a simplified format
 851          *
 852          * @param array $attachments Attachments in JSON-LD format
 853          *
 854          * @return array with attachmants in a simplified format
 855          */
 856         private static function processAttachments($attachments)
 857         {
 858                 $attachlist = [];
 859
 860                 if (empty($attachments)) {
 861                         return [];
 862                 }
 863
 864                 foreach ($attachments as $attachment) {
 865                         if (empty($attachment)) {
 866                                 continue;
 867                         }
 868
 869                         $attachlist[] = ['type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
 870                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType', '@value'),
 871                                 'name' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
 872                                 'url' => JsonLD::fetchElement($attachment, 'as:url', '@id')];
 873                 }
 874                 return $attachlist;
 875         }
 876
 877         /**
 878          * Fetches data from the object part of an activity
 879          *
 880          * @param array $object
 881          *
 882          * @return array
 883          * @throws \Exception
 884          */
 885         private static function processObject($object)
 886         {
 887                 if (!JsonLD::fetchElement($object, '@id')) {
 888                         return false;
 889                 }
 890
 891                 $object_data = [];
 892                 $object_data['object_type'] = JsonLD::fetchElement($object, '@type');
 893                 $object_data['id'] = JsonLD::fetchElement($object, '@id');
 894                 $object_data['reply-to-id'] = JsonLD::fetchElement($object, 'as:inReplyTo', '@id');
 895
 896                 // An empty "id" field is translated to "./" by the compactor, so we have to check for this content
 897                 if (empty($object_data['reply-to-id']) || ($object_data['reply-to-id'] == './')) {
 898                         $object_data['reply-to-id'] = $object_data['id'];
 899                 }
 900
 901                 $object_data['published'] = JsonLD::fetchElement($object, 'as:published', '@value');
 902                 $object_data['updated'] = JsonLD::fetchElement($object, 'as:updated', '@value');
 903
 904                 if (empty($object_data['updated'])) {
 905                         $object_data['updated'] = $object_data['published'];
 906                 }
 907
 908                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
 909                         $object_data['published'] = $object_data['updated'];
 910                 }
 911
 912                 $actor = JsonLD::fetchElement($object, 'as:attributedTo', '@id');
 913                 if (empty($actor)) {
 914                         $actor = JsonLD::fetchElement($object, 'as:actor', '@id');
 915                 }
 916
 917                 $object_data['diaspora:guid'] = JsonLD::fetchElement($object, 'diaspora:guid', '@value');
 918                 $object_data['diaspora:comment'] = JsonLD::fetchElement($object, 'diaspora:comment', '@value');
 919                 $object_data['diaspora:like'] = JsonLD::fetchElement($object, 'diaspora:like', '@value');
 920                 $object_data['actor'] = $object_data['author'] = $actor;
 921                 $object_data['context'] = JsonLD::fetchElement($object, 'as:context', '@id');
 922                 $object_data['conversation'] = JsonLD::fetchElement($object, 'ostatus:conversation', '@id');
 923                 $object_data['sensitive'] = JsonLD::fetchElement($object, 'as:sensitive');
 924                 $object_data['name'] = JsonLD::fetchElement($object, 'as:name', '@value');
 925                 $object_data['summary'] = JsonLD::fetchElement($object, 'as:summary', '@value');
 926                 $object_data['content'] = JsonLD::fetchElement($object, 'as:content', '@value');
 927                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/bbcode');
 928                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
 929                 $object_data['start-time'] = JsonLD::fetchElement($object, 'as:startTime', '@value');
 930                 $object_data['end-time'] = JsonLD::fetchElement($object, 'as:endTime', '@value');
 931                 $object_data['location'] = JsonLD::fetchElement($object, 'as:location', 'as:name', '@type', 'as:Place');
 932                 $object_data['location'] = JsonLD::fetchElement($object_data, 'location', '@value');
 933                 $object_data['latitude'] = JsonLD::fetchElement($object, 'as:location', 'as:latitude', '@type', 'as:Place');
 934                 $object_data['latitude'] = JsonLD::fetchElement($object_data, 'latitude', '@value');
 935                 $object_data['longitude'] = JsonLD::fetchElement($object, 'as:location', 'as:longitude', '@type', 'as:Place');
 936                 $object_data['longitude'] = JsonLD::fetchElement($object_data, 'longitude', '@value');
 937                 $object_data['attachments'] = self::processAttachments(JsonLD::fetchElementArray($object, 'as:attachment'));
 938                 $object_data['tags'] = self::processTags(JsonLD::fetchElementArray($object, 'as:tag'));
 939                 $object_data['emojis'] = self::processEmojis(JsonLD::fetchElementArray($object, 'as:tag', 'toot:Emoji'));
 940                 $object_data['generator'] = JsonLD::fetchElement($object, 'as:generator', 'as:name', '@type', 'as:Application');
 941                 $object_data['generator'] = JsonLD::fetchElement($object_data, 'generator', '@value');
 942                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'as:url', '@id');
 943
 944                 // Special treatment for Hubzilla links
 945                 if (is_array($object_data['alternate-url'])) {
 946                         $object_data['alternate-url'] = JsonLD::fetchElement($object_data['alternate-url'], 'as:href', '@id');
 947
 948                         if (!is_string($object_data['alternate-url'])) {
 949                                 $object_data['alternate-url'] = JsonLD::fetchElement($object['as:url'], 'as:href', '@id');
 950                         }
 951                 }
 952
 953                 $object_data['receiver'] = self::getReceivers($object, $object_data['actor'], $object_data['tags']);
 954
 955                 // Common object data:
 956
 957                 // Unhandled
 958                 // @context, type, actor, signature, mediaType, duration, replies, icon
 959
 960                 // Also missing: (Defined in the standard, but currently unused)
 961                 // audience, preview, endTime, startTime, image
 962
 963                 // Data in Notes:
 964
 965                 // Unhandled
 966                 // contentMap, announcement_count, announcements, context_id, likes, like_count
 967                 // inReplyToStatusId, shares, quoteUrl, statusnetConversationId
 968
 969                 // Data in video:
 970
 971                 // To-Do?
 972                 // category, licence, language, commentsEnabled
 973
 974                 // Unhandled
 975                 // views, waitTranscoding, state, support, subtitleLanguage
 976                 // likes, dislikes, shares, comments
 977
 978                 return $object_data;
 979         }
 980 }