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\ActivityPub;
  16 use Friendica\Util\DateTimeFormat;
  17 use Friendica\Util\HTTPSignature;
  18 use Friendica\Util\JsonLD;
  19 use Friendica\Util\LDSignature;
  20 use Friendica\Util\Strings;
  21
  22 /**
  23  * @brief ActivityPub Receiver Protocol class
  24  *
  25  * To-Do:
  26  * - Undo Announce
  27  *
  28  * Check what this is meant to do:
  29  * - Add
  30  * - Block
  31  * - Flag
  32  * - Remove
  33  * - Undo Block
  34  */
  35 class Receiver
  36 {
  37         const PUBLIC_COLLECTION = 'as:Public';
  38         const ACCOUNT_TYPES = ['as:Person', 'as:Organization', 'as:Service', 'as:Group', 'as:Application'];
  39         const CONTENT_TYPES = ['as:Note', 'as:Article', 'as:Video', 'as:Image', 'as:Event'];
  40         const ACTIVITY_TYPES = ['as:Like', 'as:Dislike', 'as:Accept', 'as:Reject', 'as:TentativeAccept'];
  41
  42         /**
  43          * Checks if the web request is done for the AP protocol
  44          *
  45          * @return bool is it AP?
  46          */
  47         public static function isRequest()
  48         {
  49                 return stristr(defaults($_SERVER, 'HTTP_ACCEPT', ''), 'application/activity+json') ||
  50                         stristr(defaults($_SERVER, 'HTTP_ACCEPT', ''), 'application/ld+json');
  51         }
  52
  53         /**
  54          * Checks incoming message from the inbox
  55          *
  56          * @param         $body
  57          * @param         $header
  58          * @param integer $uid User ID
  59          * @throws \Exception
  60          */
  61         public static function processInbox($body, $header, $uid)
  62         {
  63                 $http_signer = HTTPSignature::getSigner($body, $header);
  64                 if (empty($http_signer)) {
  65                         Logger::warning('Invalid HTTP signature, message will be discarded.');
  66                         return;
  67                 } else {
  68                         Logger::info('Valid HTTP signature', ['signer' => $http_signer]);
  69                 }
  70
  71                 $activity = json_decode($body, true);
  72
  73                 if (empty($activity)) {
  74                         Logger::warning('Invalid body.');
  75                         return;
  76                 }
  77
  78                 $ldactivity = JsonLD::compact($activity);
  79
  80                 $actor = JsonLD::fetchElement($ldactivity, 'as:actor', '@id');
  81
  82                 Logger::info('Message for user ' . $uid . ' is from actor ' . $actor);
  83
  84                 if (LDSignature::isSigned($activity)) {
  85                         $ld_signer = LDSignature::getSigner($activity);
  86                         if (empty($ld_signer)) {
  87                                 Logger::log('Invalid JSON-LD signature from ' . $actor, Logger::DEBUG);
  88                         }
  89                         if (!empty($ld_signer && ($actor == $http_signer))) {
  90                                 Logger::log('The HTTP and the JSON-LD signature belong to ' . $ld_signer, Logger::DEBUG);
  91                                 $trust_source = true;
  92                         } elseif (!empty($ld_signer)) {
  93                                 Logger::log('JSON-LD signature is signed by ' . $ld_signer, Logger::DEBUG);
  94                                 $trust_source = true;
  95                         } elseif ($actor == $http_signer) {
  96                                 Logger::log('Bad JSON-LD signature, but HTTP signer fits the actor.', Logger::DEBUG);
  97                                 $trust_source = true;
  98                         } else {
  99                                 Logger::log('Invalid JSON-LD signature and the HTTP signer is different.', Logger::DEBUG);
 100                                 $trust_source = false;
 101                         }
 102                 } elseif ($actor == $http_signer) {
 103                         Logger::log('Trusting post without JSON-LD signature, The actor fits the HTTP signer.', Logger::DEBUG);
 104                         $trust_source = true;
 105                 } else {
 106                         Logger::log('No JSON-LD signature, different actor.', Logger::DEBUG);
 107                         $trust_source = false;
 108                 }
 109
 110                 self::processActivity($ldactivity, $body, $uid, $trust_source);
 111         }
 112
 113         /**
 114          * Fetches the object type for a given object id
 115          *
 116          * @param array   $activity
 117          * @param string  $object_id Object ID of the the provided object
 118          * @param integer $uid       User ID
 119          *
 120          * @return string with object type
 121          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 122          * @throws \ImagickException
 123          */
 124         private static function fetchObjectType($activity, $object_id, $uid = 0)
 125         {
 126                 if (!empty($activity['as:object'])) {
 127                         $object_type = JsonLD::fetchElement($activity['as:object'], '@type');
 128                         if (!empty($object_type)) {
 129                                 return $object_type;
 130                         }
 131                 }
 132
 133                 if (Item::exists(['uri' => $object_id, 'gravity' => [GRAVITY_PARENT, GRAVITY_COMMENT]])) {
 134                         // We just assume "note" since it doesn't make a difference for the further processing
 135                         return 'as:Note';
 136                 }
 137
 138                 $profile = APContact::getByURL($object_id);
 139                 if (!empty($profile['type'])) {
 140                         return 'as:' . $profile['type'];
 141                 }
 142
 143                 $data = ActivityPub::fetchContent($object_id, $uid);
 144                 if (!empty($data)) {
 145                         $object = JsonLD::compact($data);
 146                         $type = JsonLD::fetchElement($object, '@type');
 147                         if (!empty($type)) {
 148                                 return $type;
 149                         }
 150                 }
 151
 152                 return null;
 153         }
 154
 155         /**
 156          * Prepare the object array
 157          *
 158          * @param array   $activity
 159          * @param integer $uid User ID
 160          * @param         $trust_source
 161          *
 162          * @return array with object data
 163          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 164          * @throws \ImagickException
 165          */
 166         private static function prepareObjectData($activity, $uid, &$trust_source)
 167         {
 168                 $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 169                 if (empty($actor)) {
 170                         Logger::log('Empty actor', Logger::DEBUG);
 171                         return [];
 172                 }
 173
 174                 $type = JsonLD::fetchElement($activity, '@type');
 175
 176                 // Fetch all receivers from to, cc, bto and bcc
 177                 $receivers = self::getReceivers($activity, $actor);
 178
 179                 // When it is a delivery to a personal inbox we add that user to the receivers
 180                 if (!empty($uid)) {
 181                         $additional = ['uid:' . $uid => $uid];
 182                         $receivers = array_merge($receivers, $additional);
 183                 } else {
 184                         // We possibly need some user to fetch private content,
 185                         // so we fetch the first out ot the list.
 186                         $uid = self::getFirstUserFromReceivers($receivers);
 187                 }
 188
 189                 Logger::log('Receivers: ' . $uid . ' - ' . json_encode($receivers), Logger::DEBUG);
 190
 191                 $object_id = JsonLD::fetchElement($activity, 'as:object', '@id');
 192                 if (empty($object_id)) {
 193                         Logger::log('No object found', Logger::DEBUG);
 194                         return [];
 195                 }
 196
 197                 if (!is_string($object_id)) {
 198                         Logger::info('Invalid object id', ['object' => $object_id]);
 199                         return [];
 200                 }
 201
 202                 $object_type = self::fetchObjectType($activity, $object_id, $uid);
 203
 204                 // Fetch the content only on activities where this matters
 205                 if (in_array($type, ['as:Create', 'as:Update', 'as:Announce'])) {
 206                         if ($type == 'as:Announce') {
 207                                 $trust_source = false;
 208                         }
 209                         $object_data = self::fetchObject($object_id, $activity['as:object'], $trust_source, $uid);
 210                         if (empty($object_data)) {
 211                                 Logger::log("Object data couldn't be processed", Logger::DEBUG);
 212                                 return [];
 213                         }
 214                         $object_data['object_id'] = $object_id;
 215
 216                         // Test if it is an answer to a mail
 217                         if (DBA::exists('mail', ['uri' => $object_data['reply-to-id']])) {
 218                                 $object_data['directmessage'] = true;
 219                         } else {
 220                                 $object_data['directmessage'] = JsonLD::fetchElement($activity, 'litepub:directMessage');
 221                         }
 222
 223                         // We had been able to retrieve the object data - so we can trust the source
 224                         $trust_source = true;
 225                 } elseif (in_array($type, array_merge(self::ACTIVITY_TYPES, ['as:Follow'])) && in_array($object_type, self::CONTENT_TYPES)) {
 226                         // Create a mostly empty array out of the activity data (instead of the object).
 227                         // This way we later don't have to check for the existence of ech individual array element.
 228                         $object_data = self::processObject($activity);
 229                         $object_data['name'] = $type;
 230                         $object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 231                         $object_data['object_id'] = $object_id;
 232                         $object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
 233                 } elseif (in_array($type, ['as:Add'])) {
 234                         $object_data = [];
 235                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 236                         $object_data['target_id'] = JsonLD::fetchElement($activity, 'as:target', '@id');
 237                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 238                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 239                         $object_data['object_content'] = JsonLD::fetchElement($activity['as:object'], 'as:content', '@type');
 240                 } else {
 241                         $object_data = [];
 242                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 243                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 244                         $object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor', '@id');
 245                         $object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
 246                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 247
 248                         // An Undo is done on the object of an object, so we need that type as well
 249                         if ($type == 'as:Undo') {
 250                                 $object_data['object_object_type'] = self::fetchObjectType([], $object_data['object_object'], $uid);
 251                         }
 252                 }
 253
 254                 $object_data = self::addActivityFields($object_data, $activity);
 255
 256                 if (empty($object_data['object_type'])) {
 257                         $object_data['object_type'] = $object_type;
 258                 }
 259
 260                 $object_data['type'] = $type;
 261                 $object_data['actor'] = $actor;
 262                 $object_data['item_receiver'] = $receivers;
 263                 $object_data['receiver'] = array_merge(defaults($object_data, 'receiver', []), $receivers);
 264
 265                 Logger::log('Processing ' . $object_data['type'] . ' ' . $object_data['object_type'] . ' ' . $object_data['id'], Logger::DEBUG);
 266
 267                 return $object_data;
 268         }
 269
 270         /**
 271          * Fetches the first user id from the receiver array
 272          *
 273          * @param array $receivers Array with receivers
 274          * @return integer user id;
 275          */
 276         public static function getFirstUserFromReceivers($receivers)
 277         {
 278                 foreach ($receivers as $receiver) {
 279                         if (!empty($receiver)) {
 280                                 return $receiver;
 281                         }
 282                 }
 283                 return 0;
 284         }
 285
 286         /**
 287          * Store the unprocessed data into the conversation table
 288          * This has to be done outside the regular function,
 289          * since we store everything - not only item posts.
 290          *
 291          * @param array  $activity Array with activity data
 292          * @param string $body     The raw message
 293          * @throws \Exception
 294          */
 295         private static function storeConversation($activity, $body)
 296         {
 297                 if (empty($body) || empty($activity['id'])) {
 298                         return;
 299                 }
 300
 301                 $conversation = [
 302                         'protocol' => Conversation::PARCEL_ACTIVITYPUB,
 303                         'item-uri' => $activity['id'],
 304                         'reply-to-uri' => defaults($activity, 'reply-to-id', ''),
 305                         'conversation-href' => defaults($activity, 'context', ''),
 306                         'conversation-uri' => defaults($activity, 'conversation', ''),
 307                         'source' => $body,
 308                         'received' => DateTimeFormat::utcNow()];
 309
 310                 DBA::insert('conversation', $conversation, true);
 311         }
 312
 313         /**
 314          * Processes the activity object
 315          *
 316          * @param array   $activity     Array with activity data
 317          * @param string  $body
 318          * @param integer $uid          User ID
 319          * @param boolean $trust_source Do we trust the source?
 320          * @throws \Exception
 321          */
 322         public static function processActivity($activity, $body = '', $uid = null, $trust_source = false)
 323         {
 324                 $type = JsonLD::fetchElement($activity, '@type');
 325                 if (!$type) {
 326                         Logger::log('Empty type', Logger::DEBUG);
 327                         return;
 328                 }
 329
 330                 if (!JsonLD::fetchElement($activity, 'as:object', '@id')) {
 331                         Logger::log('Empty object', Logger::DEBUG);
 332                         return;
 333                 }
 334
 335                 if (!JsonLD::fetchElement($activity, 'as:actor', '@id')) {
 336                         Logger::log('Empty actor', Logger::DEBUG);
 337                         return;
 338
 339                 }
 340
 341                 // Don't trust the source if "actor" differs from "attributedTo". The content could be forged.
 342                 if ($trust_source && ($type == 'as:Create') && is_array($activity['as:object'])) {
 343                         $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 344                         $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
 345                         $trust_source = ($actor == $attributed_to);
 346                         if (!$trust_source) {
 347                                 Logger::log('Not trusting actor: ' . $actor . '. It differs from attributedTo: ' . $attributed_to, Logger::DEBUG);
 348                         }
 349                 }
 350
 351                 // $trust_source is called by reference and is set to true if the content was retrieved successfully
 352                 $object_data = self::prepareObjectData($activity, $uid, $trust_source);
 353                 if (empty($object_data)) {
 354                         Logger::log('No object data found', Logger::DEBUG);
 355                         return;
 356                 }
 357
 358                 if (!$trust_source) {
 359                         Logger::log('No trust for activity type "' . $type . '", so we quit now.', Logger::DEBUG);
 360                         return;
 361                 }
 362
 363                 // Only store content related stuff - and no announces, since they possibly overwrite the original content
 364                 if (in_array($object_data['object_type'], self::CONTENT_TYPES) && ($type != 'as:Announce')) {
 365                         self::storeConversation($object_data, $body);
 366                 }
 367
 368                 // Internal flag for thread completion. See Processor.php
 369                 if (!empty($activity['thread-completion'])) {
 370                         $object_data['thread-completion'] = $activity['thread-completion'];
 371                 }
 372
 373                 switch ($type) {
 374                         case 'as:Create':
 375                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 376                                         ActivityPub\Processor::createItem($object_data);
 377                                 }
 378                                 break;
 379
 380                         case 'as:Add':
 381                                 if ($object_data['object_type'] == 'as:tag') {
 382                                         ActivityPub\Processor::addTag($object_data);
 383                                 }
 384                                 break;
 385
 386                         case 'as:Announce':
 387                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 388                                         $profile = APContact::getByURL($object_data['actor']);
 389                                         // Reshared posts from persons appear as summary at the bottom
 390                                         // If this isn't set, then a single reshare appears on top. This is used for groups.
 391                                         $object_data['thread-completion'] = ($profile['type'] != 'Group');
 392
 393                                         ActivityPub\Processor::createItem($object_data);
 394
 395                                         // Add the bottom reshare information only for persons
 396                                         if ($profile['type'] != 'Group') {
 397                                                 $announce_object_data = self::processObject($activity);
 398                                                 $announce_object_data['name'] = $type;
 399                                                 $announce_object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 400                                                 $announce_object_data['object_id'] = $object_data['object_id'];
 401                                                 $announce_object_data['object_type'] = $object_data['object_type'];
 402
 403                                                 ActivityPub\Processor::createActivity($announce_object_data, ACTIVITY2_ANNOUNCE);
 404                                         }
 405                                 }
 406                                 break;
 407
 408                         case 'as:Like':
 409                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 410                                         ActivityPub\Processor::createActivity($object_data, ACTIVITY_LIKE);
 411                                 }
 412                                 break;
 413
 414                         case 'as:Dislike':
 415                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 416                                         ActivityPub\Processor::createActivity($object_data, ACTIVITY_DISLIKE);
 417                                 }
 418                                 break;
 419
 420                         case 'as:TentativeAccept':
 421                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 422                                         ActivityPub\Processor::createActivity($object_data, ACTIVITY_ATTENDMAYBE);
 423                                 }
 424                                 break;
 425
 426                         case 'as:Update':
 427                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 428                                         ActivityPub\Processor::updateItem($object_data);
 429                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 430                                         ActivityPub\Processor::updatePerson($object_data);
 431                                 }
 432                                 break;
 433
 434                         case 'as:Delete':
 435                                 if ($object_data['object_type'] == 'as:Tombstone') {
 436                                         ActivityPub\Processor::deleteItem($object_data);
 437                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 438                                         ActivityPub\Processor::deletePerson($object_data);
 439                                 }
 440                                 break;
 441
 442                         case 'as:Follow':
 443                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 444                                         ActivityPub\Processor::followUser($object_data);
 445                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 446                                         $object_data['reply-to-id'] = $object_data['object_id'];
 447                                         ActivityPub\Processor::createActivity($object_data, ACTIVITY_FOLLOW);
 448                                 }
 449                                 break;
 450
 451                         case 'as:Accept':
 452                                 if ($object_data['object_type'] == 'as:Follow') {
 453                                         ActivityPub\Processor::acceptFollowUser($object_data);
 454                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 455                                         ActivityPub\Processor::createActivity($object_data, ACTIVITY_ATTEND);
 456                                 }
 457                                 break;
 458
 459                         case 'as:Reject':
 460                                 if ($object_data['object_type'] == 'as:Follow') {
 461                                         ActivityPub\Processor::rejectFollowUser($object_data);
 462                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 463                                         ActivityPub\Processor::createActivity($object_data, ACTIVITY_ATTENDNO);
 464                                 }
 465                                 break;
 466
 467                         case 'as:Undo':
 468                                 if (($object_data['object_type'] == 'as:Follow') &&
 469                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 470                                         ActivityPub\Processor::undoFollowUser($object_data);
 471                                 } elseif (($object_data['object_type'] == 'as:Accept') &&
 472                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 473                                         ActivityPub\Processor::rejectFollowUser($object_data);
 474                                 } elseif (in_array($object_data['object_type'], self::ACTIVITY_TYPES) &&
 475                                         in_array($object_data['object_object_type'], self::CONTENT_TYPES)) {
 476                                         ActivityPub\Processor::undoActivity($object_data);
 477                                 }
 478                                 break;
 479
 480                         default:
 481                                 Logger::log('Unknown activity: ' . $type . ' ' . $object_data['object_type'], Logger::DEBUG);
 482                                 break;
 483                 }
 484         }
 485
 486         /**
 487          * Fetch the receiver list from an activity array
 488          *
 489          * @param array  $activity
 490          * @param string $actor
 491          * @param array  $tags
 492          *
 493          * @return array with receivers (user id)
 494          * @throws \Exception
 495          */
 496         private static function getReceivers($activity, $actor, $tags = [])
 497         {
 498                 $receivers = [];
 499
 500                 // When it is an answer, we inherite the receivers from the parent
 501                 $replyto = JsonLD::fetchElement($activity, 'as:inReplyTo', '@id');
 502                 if (!empty($replyto)) {
 503                         $parents = Item::select(['uid'], ['uri' => $replyto]);
 504                         while ($parent = Item::fetch($parents)) {
 505                                 $receivers['uid:' . $parent['uid']] = $parent['uid'];
 506                         }
 507                 }
 508
 509                 if (!empty($actor)) {
 510                         $profile = APContact::getByURL($actor);
 511                         $followers = defaults($profile, 'followers', '');
 512
 513                         Logger::log('Actor: ' . $actor . ' - Followers: ' . $followers, Logger::DEBUG);
 514                 } else {
 515                         Logger::log('Empty actor', Logger::DEBUG);
 516                         $followers = '';
 517                 }
 518
 519                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
 520                         $receiver_list = JsonLD::fetchElementArray($activity, $element, '@id');
 521                         if (empty($receiver_list)) {
 522                                 continue;
 523                         }
 524
 525                         foreach ($receiver_list as $receiver) {
 526                                 if ($receiver == self::PUBLIC_COLLECTION) {
 527                                         $receivers['uid:0'] = 0;
 528                                 }
 529
 530                                 if (($receiver == self::PUBLIC_COLLECTION) && !empty($actor)) {
 531                                         // This will most likely catch all OStatus connections to Mastodon
 532                                         $condition = ['alias' => [$actor, Strings::normaliseLink($actor)], 'rel' => [Contact::SHARING, Contact::FRIEND]
 533                                                 , 'archive' => false, 'pending' => false];
 534                                         $contacts = DBA::select('contact', ['uid'], $condition);
 535                                         while ($contact = DBA::fetch($contacts)) {
 536                                                 if ($contact['uid'] != 0) {
 537                                                         $receivers['uid:' . $contact['uid']] = $contact['uid'];
 538                                                 }
 539                                         }
 540                                         DBA::close($contacts);
 541                                 }
 542
 543                                 if (in_array($receiver, [$followers, self::PUBLIC_COLLECTION]) && !empty($actor)) {
 544                                         $receivers = array_merge($receivers, self::getReceiverForActor($actor, $tags));
 545                                         continue;
 546                                 }
 547
 548                                 // Fetching all directly addressed receivers
 549                                 $condition = ['self' => true, 'nurl' => Strings::normaliseLink($receiver)];
 550                                 $contact = DBA::selectFirst('contact', ['uid', 'contact-type'], $condition);
 551                                 if (!DBA::isResult($contact)) {
 552                                         continue;
 553                                 }
 554
 555                                 // Check if the potential receiver is following the actor
 556                                 // Exception: The receiver is targetted via "to" or this is a comment
 557                                 if ((($element != 'as:to') && empty($replyto)) || ($contact['contact-type'] == Contact::TYPE_COMMUNITY)) {
 558                                         $networks = Protocol::FEDERATED;
 559                                         $condition = ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
 560                                                 'network' => $networks, 'archive' => false, 'pending' => false, 'uid' => $contact['uid']];
 561
 562                                         // Forum posts are only accepted from forum contacts
 563                                         if ($contact['contact-type'] == Contact::TYPE_COMMUNITY) {
 564                                                 $condition['rel'] = [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER];
 565                                         }
 566
 567                                         if (!DBA::exists('contact', $condition)) {
 568                                                 continue;
 569                                         }
 570                                 }
 571
 572                                 $receivers['uid:' . $contact['uid']] = $contact['uid'];
 573                         }
 574                 }
 575
 576                 self::switchContacts($receivers, $actor);
 577
 578                 return $receivers;
 579         }
 580
 581         /**
 582          * Fetch the receiver list of a given actor
 583          *
 584          * @param string $actor
 585          * @param array  $tags
 586          *
 587          * @return array with receivers (user id)
 588          * @throws \Exception
 589          */
 590         public static function getReceiverForActor($actor, $tags)
 591         {
 592                 $receivers = [];
 593                 $networks = Protocol::FEDERATED;
 594                 $condition = ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER],
 595                         'network' => $networks, 'archive' => false, 'pending' => false];
 596                 $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
 597                 while ($contact = DBA::fetch($contacts)) {
 598                         if (self::isValidReceiverForActor($contact, $actor, $tags)) {
 599                                 $receivers['uid:' . $contact['uid']] = $contact['uid'];
 600                         }
 601                 }
 602                 DBA::close($contacts);
 603                 return $receivers;
 604         }
 605
 606         /**
 607          * Tests if the contact is a valid receiver for this actor
 608          *
 609          * @param array  $contact
 610          * @param string $actor
 611          * @param array  $tags
 612          *
 613          * @return bool with receivers (user id)
 614          * @throws \Exception
 615          */
 616         private static function isValidReceiverForActor($contact, $actor, $tags)
 617         {
 618                 // Public contacts are no valid receiver
 619                 if ($contact['uid'] == 0) {
 620                         return false;
 621                 }
 622
 623                 // Are we following the contact? Then this is a valid receiver
 624                 if (in_array($contact['rel'], [Contact::SHARING, Contact::FRIEND])) {
 625                         return true;
 626                 }
 627
 628                 // When the possible receiver isn't a community, then it is no valid receiver
 629                 $owner = User::getOwnerDataById($contact['uid']);
 630                 if (empty($owner) || ($owner['contact-type'] != Contact::TYPE_COMMUNITY)) {
 631                         return false;
 632                 }
 633
 634                 // Is the community account tagged?
 635                 foreach ($tags as $tag) {
 636                         if ($tag['type'] != 'Mention') {
 637                                 continue;
 638                         }
 639
 640                         if ($tag['href'] == $owner['url']) {
 641                                 return true;
 642                         }
 643                 }
 644
 645                 return false;
 646         }
 647
 648         /**
 649          * Switches existing contacts to ActivityPub
 650          *
 651          * @param integer $cid Contact ID
 652          * @param integer $uid User ID
 653          * @param string  $url Profile URL
 654          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 655          * @throws \ImagickException
 656          */
 657         public static function switchContact($cid, $uid, $url)
 658         {
 659                 Contact::updateFromProbe($cid, '', true);
 660
 661                 Logger::log('Switch contact ' . $cid . ' (' . $url . ') for user ' . $uid . ' to ActivityPub');
 662
 663                 // Send a new follow request to be sure that the connection still exists
 664                 if (($uid != 0) && DBA::exists('contact', ['id' => $cid, 'rel' => [Contact::SHARING, Contact::FRIEND]])) {
 665                         ActivityPub\Transmitter::sendActivity('Follow', $url, $uid);
 666                         Logger::log('Send a new follow request to ' . $url . ' for user ' . $uid, Logger::DEBUG);
 667                 }
 668         }
 669
 670         /**
 671          *
 672          *
 673          * @param $receivers
 674          * @param $actor
 675          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 676          * @throws \ImagickException
 677          */
 678         private static function switchContacts($receivers, $actor)
 679         {
 680                 if (empty($actor)) {
 681                         return;
 682                 }
 683
 684                 foreach ($receivers as $receiver) {
 685                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver, 'network' => Protocol::OSTATUS, 'nurl' => Strings::normaliseLink($actor)]);
 686                         if (DBA::isResult($contact)) {
 687                                 self::switchContact($contact['id'], $receiver, $actor);
 688                         }
 689
 690                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver, 'network' => Protocol::OSTATUS, 'alias' => [Strings::normaliseLink($actor), $actor]]);
 691                         if (DBA::isResult($contact)) {
 692                                 self::switchContact($contact['id'], $receiver, $actor);
 693                         }
 694                 }
 695         }
 696
 697         /**
 698          *
 699          *
 700          * @param       $object_data
 701          * @param array $activity
 702          *
 703          * @return mixed
 704          */
 705         private static function addActivityFields($object_data, $activity)
 706         {
 707                 if (!empty($activity['published']) && empty($object_data['published'])) {
 708                         $object_data['published'] = JsonLD::fetchElement($activity, 'as:published', '@value');
 709                 }
 710
 711                 if (!empty($activity['diaspora:guid']) && empty($object_data['diaspora:guid'])) {
 712                         $object_data['diaspora:guid'] = JsonLD::fetchElement($activity, 'diaspora:guid', '@value');
 713                 }
 714
 715                 $object_data['service'] = JsonLD::fetchElement($activity, 'as:instrument', 'as:name', '@type', 'as:Service');
 716                 $object_data['service'] = JsonLD::fetchElement($object_data, 'service', '@value');
 717
 718                 return $object_data;
 719         }
 720
 721         /**
 722          * Fetches the object data from external ressources if needed
 723          *
 724          * @param string  $object_id    Object ID of the the provided object
 725          * @param array   $object       The provided object array
 726          * @param boolean $trust_source Do we trust the provided object?
 727          * @param integer $uid          User ID for the signature that we use to fetch data
 728          *
 729          * @return array|false with trusted and valid object data
 730          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 731          * @throws \ImagickException
 732          */
 733         private static function fetchObject(string $object_id, array $object = [], bool $trust_source = false, int $uid = 0)
 734         {
 735                 // By fetching the type we check if the object is complete.
 736                 $type = JsonLD::fetchElement($object, '@type');
 737
 738                 if (!$trust_source || empty($type)) {
 739                         $data = ActivityPub::fetchContent($object_id, $uid);
 740                         if (!empty($data)) {
 741                                 $object = JsonLD::compact($data);
 742                                 Logger::log('Fetched content for ' . $object_id, Logger::DEBUG);
 743                         } else {
 744                                 Logger::log('Empty content for ' . $object_id . ', check if content is available locally.', Logger::DEBUG);
 745
 746                                 $item = Item::selectFirst([], ['uri' => $object_id]);
 747                                 if (!DBA::isResult($item)) {
 748                                         Logger::log('Object with url ' . $object_id . ' was not found locally.', Logger::DEBUG);
 749                                         return false;
 750                                 }
 751                                 Logger::log('Using already stored item for url ' . $object_id, Logger::DEBUG);
 752                                 $data = ActivityPub\Transmitter::createNote($item);
 753                                 $object = JsonLD::compact($data);
 754                         }
 755                 } else {
 756                         Logger::log('Using original object for url ' . $object_id, Logger::DEBUG);
 757                 }
 758
 759                 $type = JsonLD::fetchElement($object, '@type');
 760
 761                 if (empty($type)) {
 762                         Logger::log('Empty type', Logger::DEBUG);
 763                         return false;
 764                 }
 765
 766                 if (in_array($type, self::CONTENT_TYPES)) {
 767                         return self::processObject($object);
 768                 }
 769
 770                 if ($type == 'as:Announce') {
 771                         $object_id = JsonLD::fetchElement($object, 'object', '@id');
 772                         if (empty($object_id) || !is_string($object_id)) {
 773                                 return false;
 774                         }
 775                         return self::fetchObject($object_id, [], false, $uid);
 776                 }
 777
 778                 Logger::log('Unhandled object type: ' . $type, Logger::DEBUG);
 779                 return false;
 780         }
 781
 782         /**
 783          * Convert tags from JSON-LD format into a simplified format
 784          *
 785          * @param array $tags Tags in JSON-LD format
 786          *
 787          * @return array with tags in a simplified format
 788          */
 789         private static function processTags($tags)
 790         {
 791                 $taglist = [];
 792
 793                 if (empty($tags)) {
 794                         return [];
 795                 }
 796
 797                 foreach ($tags as $tag) {
 798                         if (empty($tag)) {
 799                                 continue;
 800                         }
 801
 802                         $element = ['type' => str_replace('as:', '', JsonLD::fetchElement($tag, '@type')),
 803                                 'href' => JsonLD::fetchElement($tag, 'as:href', '@id'),
 804                                 'name' => JsonLD::fetchElement($tag, 'as:name', '@value')];
 805
 806                         if (empty($element['type'])) {
 807                                 continue;
 808                         }
 809
 810                         $taglist[] = $element;
 811                 }
 812                 return $taglist;
 813         }
 814
 815         /**
 816          * Convert emojis from JSON-LD format into a simplified format
 817          *
 818          * @param $emojis
 819          * @return array with emojis in a simplified format
 820          */
 821         private static function processEmojis($emojis)
 822         {
 823                 $emojilist = [];
 824
 825                 if (empty($emojis)) {
 826                         return [];
 827                 }
 828
 829                 foreach ($emojis as $emoji) {
 830                         if (empty($emoji) || (JsonLD::fetchElement($emoji, '@type') != 'toot:Emoji') || empty($emoji['as:icon'])) {
 831                                 continue;
 832                         }
 833
 834                         $url = JsonLD::fetchElement($emoji['as:icon'], 'as:url', '@id');
 835                         $element = ['name' => JsonLD::fetchElement($emoji, 'as:name', '@value'),
 836                                 'href' => $url];
 837
 838                         $emojilist[] = $element;
 839                 }
 840                 return $emojilist;
 841         }
 842
 843         /**
 844          * Convert attachments from JSON-LD format into a simplified format
 845          *
 846          * @param array $attachments Attachments in JSON-LD format
 847          *
 848          * @return array with attachmants in a simplified format
 849          */
 850         private static function processAttachments($attachments)
 851         {
 852                 $attachlist = [];
 853
 854                 if (empty($attachments)) {
 855                         return [];
 856                 }
 857
 858                 foreach ($attachments as $attachment) {
 859                         if (empty($attachment)) {
 860                                 continue;
 861                         }
 862
 863                         $attachlist[] = ['type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
 864                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType', '@value'),
 865                                 'name' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
 866                                 'url' => JsonLD::fetchElement($attachment, 'as:url', '@id')];
 867                 }
 868                 return $attachlist;
 869         }
 870
 871         /**
 872          * Fetches data from the object part of an activity
 873          *
 874          * @param array $object
 875          *
 876          * @return array
 877          * @throws \Exception
 878          */
 879         private static function processObject($object)
 880         {
 881                 if (!JsonLD::fetchElement($object, '@id')) {
 882                         return false;
 883                 }
 884
 885                 $object_data = [];
 886                 $object_data['object_type'] = JsonLD::fetchElement($object, '@type');
 887                 $object_data['id'] = JsonLD::fetchElement($object, '@id');
 888                 $object_data['reply-to-id'] = JsonLD::fetchElement($object, 'as:inReplyTo', '@id');
 889
 890                 // An empty "id" field is translated to "./" by the compactor, so we have to check for this content
 891                 if (empty($object_data['reply-to-id']) || ($object_data['reply-to-id'] == './')) {
 892                         $object_data['reply-to-id'] = $object_data['id'];
 893                 }
 894
 895                 $object_data['published'] = JsonLD::fetchElement($object, 'as:published', '@value');
 896                 $object_data['updated'] = JsonLD::fetchElement($object, 'as:updated', '@value');
 897
 898                 if (empty($object_data['updated'])) {
 899                         $object_data['updated'] = $object_data['published'];
 900                 }
 901
 902                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
 903                         $object_data['published'] = $object_data['updated'];
 904                 }
 905
 906                 $actor = JsonLD::fetchElement($object, 'as:attributedTo', '@id');
 907                 if (empty($actor)) {
 908                         $actor = JsonLD::fetchElement($object, 'as:actor', '@id');
 909                 }
 910
 911                 $object_data['diaspora:guid'] = JsonLD::fetchElement($object, 'diaspora:guid', '@value');
 912                 $object_data['diaspora:comment'] = JsonLD::fetchElement($object, 'diaspora:comment', '@value');
 913                 $object_data['diaspora:like'] = JsonLD::fetchElement($object, 'diaspora:like', '@value');
 914                 $object_data['actor'] = $object_data['author'] = $actor;
 915                 $object_data['context'] = JsonLD::fetchElement($object, 'as:context', '@id');
 916                 $object_data['conversation'] = JsonLD::fetchElement($object, 'ostatus:conversation', '@id');
 917                 $object_data['sensitive'] = JsonLD::fetchElement($object, 'as:sensitive');
 918                 $object_data['name'] = JsonLD::fetchElement($object, 'as:name', '@value');
 919                 $object_data['summary'] = JsonLD::fetchElement($object, 'as:summary', '@value');
 920                 $object_data['content'] = JsonLD::fetchElement($object, 'as:content', '@value');
 921                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/bbcode');
 922                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
 923                 $object_data['start-time'] = JsonLD::fetchElement($object, 'as:startTime', '@value');
 924                 $object_data['end-time'] = JsonLD::fetchElement($object, 'as:endTime', '@value');
 925                 $object_data['location'] = JsonLD::fetchElement($object, 'as:location', 'as:name', '@type', 'as:Place');
 926                 $object_data['location'] = JsonLD::fetchElement($object_data, 'location', '@value');
 927                 $object_data['latitude'] = JsonLD::fetchElement($object, 'as:location', 'as:latitude', '@type', 'as:Place');
 928                 $object_data['latitude'] = JsonLD::fetchElement($object_data, 'latitude', '@value');
 929                 $object_data['longitude'] = JsonLD::fetchElement($object, 'as:location', 'as:longitude', '@type', 'as:Place');
 930                 $object_data['longitude'] = JsonLD::fetchElement($object_data, 'longitude', '@value');
 931                 $object_data['attachments'] = self::processAttachments(JsonLD::fetchElementArray($object, 'as:attachment'));
 932                 $object_data['tags'] = self::processTags(JsonLD::fetchElementArray($object, 'as:tag'));
 933                 $object_data['emojis'] = self::processEmojis(JsonLD::fetchElementArray($object, 'as:tag', 'toot:Emoji'));
 934                 $object_data['generator'] = JsonLD::fetchElement($object, 'as:generator', 'as:name', '@type', 'as:Application');
 935                 $object_data['generator'] = JsonLD::fetchElement($object_data, 'generator', '@value');
 936                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'as:url', '@id');
 937
 938                 // Special treatment for Hubzilla links
 939                 if (is_array($object_data['alternate-url'])) {
 940                         $object_data['alternate-url'] = JsonLD::fetchElement($object_data['alternate-url'], 'as:href', '@id');
 941
 942                         if (!is_string($object_data['alternate-url'])) {
 943                                 $object_data['alternate-url'] = JsonLD::fetchElement($object['as:url'], 'as:href', '@id');
 944                         }
 945                 }
 946
 947                 $object_data['receiver'] = self::getReceivers($object, $object_data['actor'], $object_data['tags']);
 948
 949                 // Common object data:
 950
 951                 // Unhandled
 952                 // @context, type, actor, signature, mediaType, duration, replies, icon
 953
 954                 // Also missing: (Defined in the standard, but currently unused)
 955                 // audience, preview, endTime, startTime, image
 956
 957                 // Data in Notes:
 958
 959                 // Unhandled
 960                 // contentMap, announcement_count, announcements, context_id, likes, like_count
 961                 // inReplyToStatusId, shares, quoteUrl, statusnetConversationId
 962
 963                 // Data in video:
 964
 965                 // To-Do?
 966                 // category, licence, language, commentsEnabled
 967
 968                 // Unhandled
 969                 // views, waitTranscoding, state, support, subtitleLanguage
 970                 // likes, dislikes, shares, comments
 971
 972                 return $object_data;
 973         }
 974 }