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