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                 $object_type = self::fetchObjectType($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                         // Test if it is an answer to a mail
 212                         if (DBA::exists('mail', ['uri' => $object_data['reply-to-id']])) {
 213                                 $object_data['directmessage'] = true;
 214                         } else {
 215                                 $object_data['directmessage'] = JsonLD::fetchElement($activity, 'litepub:directMessage');
 216                         }
 217
 218                         // We had been able to retrieve the object data - so we can trust the source
 219                         $trust_source = true;
 220                 } elseif (in_array($type, ['as:Like', 'as:Dislike']) ||
 221                         (($type == 'as:Follow') && in_array($object_type, self::CONTENT_TYPES))) {
 222                         // Create a mostly empty array out of the activity data (instead of the object).
 223                         // This way we later don't have to check for the existence of ech individual array element.
 224                         $object_data = self::processObject($activity);
 225                         $object_data['name'] = $type;
 226                         $object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 227                         $object_data['object_id'] = $object_id;
 228                         $object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
 229                 } elseif (in_array($type, ['as:Add'])) {
 230                         $object_data = [];
 231                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 232                         $object_data['target_id'] = JsonLD::fetchElement($activity, 'as:target', '@id');
 233                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 234                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 235                         $object_data['object_content'] = JsonLD::fetchElement($activity['as:object'], 'as:content', '@type');
 236                 } else {
 237                         $object_data = [];
 238                         $object_data['id'] = JsonLD::fetchElement($activity, '@id');
 239                         $object_data['object_id'] = JsonLD::fetchElement($activity, 'as:object', '@id');
 240                         $object_data['object_actor'] = JsonLD::fetchElement($activity['as:object'], 'as:actor', '@id');
 241                         $object_data['object_object'] = JsonLD::fetchElement($activity['as:object'], 'as:object');
 242                         $object_data['object_type'] = JsonLD::fetchElement($activity['as:object'], '@type');
 243
 244                         // An Undo is done on the object of an object, so we need that type as well
 245                         if ($type == 'as:Undo') {
 246                                 $object_data['object_object_type'] = self::fetchObjectType([], $object_data['object_object'], $uid);
 247                         }
 248                 }
 249
 250                 $object_data = self::addActivityFields($object_data, $activity);
 251
 252                 if (empty($object_data['object_type'])) {
 253                         $object_data['object_type'] = $object_type;
 254                 }
 255
 256                 $object_data['type'] = $type;
 257                 $object_data['actor'] = $actor;
 258                 $object_data['item_receiver'] = $receivers;
 259                 $object_data['receiver'] = array_merge(defaults($object_data, 'receiver', []), $receivers);
 260
 261                 Logger::log('Processing ' . $object_data['type'] . ' ' . $object_data['object_type'] . ' ' . $object_data['id'], Logger::DEBUG);
 262
 263                 return $object_data;
 264         }
 265
 266         /**
 267          * Fetches the first user id from the receiver array
 268          *
 269          * @param array $receivers Array with receivers
 270          * @return integer user id;
 271          */
 272         public static function getFirstUserFromReceivers($receivers)
 273         {
 274                 foreach ($receivers as $receiver) {
 275                         if (!empty($receiver)) {
 276                                 return $receiver;
 277                         }
 278                 }
 279                 return 0;
 280         }
 281
 282         /**
 283          * Store the unprocessed data into the conversation table
 284          * This has to be done outside the regular function,
 285          * since we store everything - not only item posts.
 286          *
 287          * @param array  $activity Array with activity data
 288          * @param string $body     The raw message
 289          * @throws \Exception
 290          */
 291         private static function storeConversation($activity, $body)
 292         {
 293                 if (empty($body) || empty($activity['id'])) {
 294                         return;
 295                 }
 296
 297                 $conversation = [
 298                         'protocol' => Conversation::PARCEL_ACTIVITYPUB,
 299                         'item-uri' => $activity['id'],
 300                         'reply-to-uri' => defaults($activity, 'reply-to-id', ''),
 301                         'conversation-href' => defaults($activity, 'context', ''),
 302                         'conversation-uri' => defaults($activity, 'conversation', ''),
 303                         'source' => $body,
 304                         'received' => DateTimeFormat::utcNow()];
 305
 306                 DBA::insert('conversation', $conversation, true);
 307         }
 308
 309         /**
 310          * Processes the activity object
 311          *
 312          * @param array   $activity     Array with activity data
 313          * @param string  $body
 314          * @param integer $uid          User ID
 315          * @param boolean $trust_source Do we trust the source?
 316          * @throws \Exception
 317          */
 318         public static function processActivity($activity, $body = '', $uid = null, $trust_source = false)
 319         {
 320                 $type = JsonLD::fetchElement($activity, '@type');
 321                 if (!$type) {
 322                         Logger::log('Empty type', Logger::DEBUG);
 323                         return;
 324                 }
 325
 326                 if (!JsonLD::fetchElement($activity, 'as:object', '@id')) {
 327                         Logger::log('Empty object', Logger::DEBUG);
 328                         return;
 329                 }
 330
 331                 if (!JsonLD::fetchElement($activity, 'as:actor', '@id')) {
 332                         Logger::log('Empty actor', Logger::DEBUG);
 333                         return;
 334
 335                 }
 336
 337                 // Don't trust the source if "actor" differs from "attributedTo". The content could be forged.
 338                 if ($trust_source && ($type == 'as:Create') && is_array($activity['as:object'])) {
 339                         $actor = JsonLD::fetchElement($activity, 'as:actor', '@id');
 340                         $attributed_to = JsonLD::fetchElement($activity['as:object'], 'as:attributedTo', '@id');
 341                         $trust_source = ($actor == $attributed_to);
 342                         if (!$trust_source) {
 343                                 Logger::log('Not trusting actor: ' . $actor . '. It differs from attributedTo: ' . $attributed_to, Logger::DEBUG);
 344                         }
 345                 }
 346
 347                 // $trust_source is called by reference and is set to true if the content was retrieved successfully
 348                 $object_data = self::prepareObjectData($activity, $uid, $trust_source);
 349                 if (empty($object_data)) {
 350                         Logger::log('No object data found', Logger::DEBUG);
 351                         return;
 352                 }
 353
 354                 if (!$trust_source) {
 355                         Logger::log('No trust for activity type "' . $type . '", so we quit now.', Logger::DEBUG);
 356                         return;
 357                 }
 358
 359                 // Only store content related stuff - and no announces, since they possibly overwrite the original content
 360                 if (in_array($object_data['object_type'], self::CONTENT_TYPES) && ($type != 'as:Announce')) {
 361                         self::storeConversation($object_data, $body);
 362                 }
 363
 364                 // Internal flag for thread completion. See Processor.php
 365                 if (!empty($activity['thread-completion'])) {
 366                         $object_data['thread-completion'] = $activity['thread-completion'];
 367                 }
 368
 369                 switch ($type) {
 370                         case 'as:Create':
 371                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 372                                         ActivityPub\Processor::createItem($object_data);
 373                                 }
 374                                 break;
 375
 376                         case 'as:Add':
 377                                 if ($object_data['object_type'] == 'as:tag') {
 378                                         ActivityPub\Processor::addTag($object_data);
 379                                 }
 380                                 break;
 381
 382                         case 'as:Announce':
 383                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 384                                         $profile = APContact::getByURL($object_data['actor']);
 385                                         if ($profile['type'] == 'Person') {
 386                                                 // Reshared posts from persons appear as summary at the bottom
 387                                                 // If this isn't set, then a single reshare appears on top. This is used for groups.
 388                                                 $object_data['thread-completion'] = true;
 389                                         }
 390                                         ActivityPub\Processor::createItem($object_data);
 391
 392                                         // Add the bottom reshare information only for persons
 393                                         if ($profile['type'] == 'Person') {
 394                                                 $announce_object_data = self::processObject($activity);
 395                                                 $announce_object_data['name'] = $type;
 396                                                 $announce_object_data['author'] = JsonLD::fetchElement($activity, 'as:actor', '@id');
 397                                                 $announce_object_data['object_id'] = $object_data['object_id'];
 398                                                 $announce_object_data['object_type'] = $object_data['object_type'];
 399
 400                                                 ActivityPub\Processor::createActivity($announce_object_data, ACTIVITY2_ANNOUNCE);
 401                                         }
 402                                 }
 403                                 break;
 404
 405                         case 'as:Like':
 406                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 407                                         ActivityPub\Processor::createActivity($object_data, ACTIVITY_LIKE);
 408                                 }
 409                                 break;
 410
 411                         case 'as:Dislike':
 412                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 413                                         ActivityPub\Processor::createActivity($object_data, ACTIVITY_DISLIKE);
 414                                 }
 415                                 break;
 416
 417                         case 'as:TentativeAccept':
 418                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 419                                         ActivityPub\Processor::createActivity($object_data, ACTIVITY_ATTENDMAYBE);
 420                                 }
 421                                 break;
 422
 423                         case 'as:Update':
 424                                 if (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 425                                         ActivityPub\Processor::updateItem($object_data);
 426                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 427                                         ActivityPub\Processor::updatePerson($object_data);
 428                                 }
 429                                 break;
 430
 431                         case 'as:Delete':
 432                                 if ($object_data['object_type'] == 'as:Tombstone') {
 433                                         ActivityPub\Processor::deleteItem($object_data);
 434                                 } elseif (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 435                                         ActivityPub\Processor::deletePerson($object_data);
 436                                 }
 437                                 break;
 438
 439                         case 'as:Follow':
 440                                 if (in_array($object_data['object_type'], self::ACCOUNT_TYPES)) {
 441                                         ActivityPub\Processor::followUser($object_data);
 442                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 443                                         $object_data['reply-to-id'] = $object_data['object_id'];
 444                                         ActivityPub\Processor::createActivity($object_data, ACTIVITY_FOLLOW);
 445                                 }
 446                                 break;
 447
 448                         case 'as:Accept':
 449                                 if ($object_data['object_type'] == 'as:Follow') {
 450                                         ActivityPub\Processor::acceptFollowUser($object_data);
 451                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 452                                         ActivityPub\Processor::createActivity($object_data, ACTIVITY_ATTEND);
 453                                 }
 454                                 break;
 455
 456                         case 'as:Reject':
 457                                 if ($object_data['object_type'] == 'as:Follow') {
 458                                         ActivityPub\Processor::rejectFollowUser($object_data);
 459                                 } elseif (in_array($object_data['object_type'], self::CONTENT_TYPES)) {
 460                                         ActivityPub\Processor::createActivity($object_data, ACTIVITY_ATTENDNO);
 461                                 }
 462                                 break;
 463
 464                         case 'as:Undo':
 465                                 if (($object_data['object_type'] == 'as:Follow') &&
 466                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 467                                         ActivityPub\Processor::undoFollowUser($object_data);
 468                                 } elseif (($object_data['object_type'] == 'as:Accept') &&
 469                                         in_array($object_data['object_object_type'], self::ACCOUNT_TYPES)) {
 470                                         ActivityPub\Processor::rejectFollowUser($object_data);
 471                                 } elseif (in_array($object_data['object_type'], self::ACTIVITY_TYPES) &&
 472                                         in_array($object_data['object_object_type'], self::CONTENT_TYPES)) {
 473                                         ActivityPub\Processor::undoActivity($object_data);
 474                                 }
 475                                 break;
 476
 477                         default:
 478                                 Logger::log('Unknown activity: ' . $type . ' ' . $object_data['object_type'], Logger::DEBUG);
 479                                 break;
 480                 }
 481         }
 482
 483         /**
 484          * Fetch the receiver list from an activity array
 485          *
 486          * @param array  $activity
 487          * @param string $actor
 488          * @param array  $tags
 489          *
 490          * @return array with receivers (user id)
 491          * @throws \Exception
 492          */
 493         private static function getReceivers($activity, $actor, $tags = [])
 494         {
 495                 $receivers = [];
 496
 497                 // When it is an answer, we inherite the receivers from the parent
 498                 $replyto = JsonLD::fetchElement($activity, 'as:inReplyTo', '@id');
 499                 if (!empty($replyto)) {
 500                         $parents = Item::select(['uid'], ['uri' => $replyto]);
 501                         while ($parent = Item::fetch($parents)) {
 502                                 $receivers['uid:' . $parent['uid']] = $parent['uid'];
 503                         }
 504                 }
 505
 506                 if (!empty($actor)) {
 507                         $profile = APContact::getByURL($actor);
 508                         $followers = defaults($profile, 'followers', '');
 509
 510                         Logger::log('Actor: ' . $actor . ' - Followers: ' . $followers, Logger::DEBUG);
 511                 } else {
 512                         Logger::log('Empty actor', Logger::DEBUG);
 513                         $followers = '';
 514                 }
 515
 516                 foreach (['as:to', 'as:cc', 'as:bto', 'as:bcc'] as $element) {
 517                         $receiver_list = JsonLD::fetchElementArray($activity, $element, '@id');
 518                         if (empty($receiver_list)) {
 519                                 continue;
 520                         }
 521
 522                         foreach ($receiver_list as $receiver) {
 523                                 if ($receiver == self::PUBLIC_COLLECTION) {
 524                                         $receivers['uid:0'] = 0;
 525                                 }
 526
 527                                 if (($receiver == self::PUBLIC_COLLECTION) && !empty($actor)) {
 528                                         // This will most likely catch all OStatus connections to Mastodon
 529                                         $condition = ['alias' => [$actor, Strings::normaliseLink($actor)], 'rel' => [Contact::SHARING, Contact::FRIEND]
 530                                                 , 'archive' => false, 'pending' => false];
 531                                         $contacts = DBA::select('contact', ['uid'], $condition);
 532                                         while ($contact = DBA::fetch($contacts)) {
 533                                                 if ($contact['uid'] != 0) {
 534                                                         $receivers['uid:' . $contact['uid']] = $contact['uid'];
 535                                                 }
 536                                         }
 537                                         DBA::close($contacts);
 538                                 }
 539
 540                                 if (in_array($receiver, [$followers, self::PUBLIC_COLLECTION]) && !empty($actor)) {
 541                                         $receivers = array_merge($receivers, self::getReceiverForActor($actor, $tags));
 542                                         continue;
 543                                 }
 544
 545                                 // Fetching all directly addressed receivers
 546                                 $condition = ['self' => true, 'nurl' => Strings::normaliseLink($receiver)];
 547                                 $contact = DBA::selectFirst('contact', ['uid', 'contact-type'], $condition);
 548                                 if (!DBA::isResult($contact)) {
 549                                         continue;
 550                                 }
 551
 552                                 // Check if the potential receiver is following the actor
 553                                 // Exception: The receiver is targetted via "to" or this is a comment
 554                                 if ((($element != 'as:to') && empty($replyto)) || ($contact['contact-type'] == Contact::TYPE_COMMUNITY)) {
 555                                         $networks = [Protocol::ACTIVITYPUB, Protocol::DFRN, Protocol::DIASPORA, Protocol::OSTATUS];
 556                                         $condition = ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
 557                                                 'network' => $networks, 'archive' => false, 'pending' => false, 'uid' => $contact['uid']];
 558
 559                                         // Forum posts are only accepted from forum contacts
 560                                         if ($contact['contact-type'] == Contact::TYPE_COMMUNITY) {
 561                                                 $condition['rel'] = [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER];
 562                                         }
 563
 564                                         if (!DBA::exists('contact', $condition)) {
 565                                                 continue;
 566                                         }
 567                                 }
 568
 569                                 $receivers['uid:' . $contact['uid']] = $contact['uid'];
 570                         }
 571                 }
 572
 573                 self::switchContacts($receivers, $actor);
 574
 575                 return $receivers;
 576         }
 577
 578         /**
 579          * Fetch the receiver list of a given actor
 580          *
 581          * @param string $actor
 582          * @param array  $tags
 583          *
 584          * @return array with receivers (user id)
 585          * @throws \Exception
 586          */
 587         public static function getReceiverForActor($actor, $tags)
 588         {
 589                 $receivers = [];
 590                 $networks = [Protocol::ACTIVITYPUB, Protocol::DFRN, Protocol::DIASPORA, Protocol::OSTATUS];
 591                 $condition = ['nurl' => Strings::normaliseLink($actor), 'rel' => [Contact::SHARING, Contact::FRIEND, Contact::FOLLOWER],
 592                         'network' => $networks, 'archive' => false, 'pending' => false];
 593                 $contacts = DBA::select('contact', ['uid', 'rel'], $condition);
 594                 while ($contact = DBA::fetch($contacts)) {
 595                         if (self::isValidReceiverForActor($contact, $actor, $tags)) {
 596                                 $receivers['uid:' . $contact['uid']] = $contact['uid'];
 597                         }
 598                 }
 599                 DBA::close($contacts);
 600                 return $receivers;
 601         }
 602
 603         /**
 604          * Tests if the contact is a valid receiver for this actor
 605          *
 606          * @param array  $contact
 607          * @param string $actor
 608          * @param array  $tags
 609          *
 610          * @return bool with receivers (user id)
 611          * @throws \Exception
 612          */
 613         private static function isValidReceiverForActor($contact, $actor, $tags)
 614         {
 615                 // Public contacts are no valid receiver
 616                 if ($contact['uid'] == 0) {
 617                         return false;
 618                 }
 619
 620                 // Are we following the contact? Then this is a valid receiver
 621                 if (in_array($contact['rel'], [Contact::SHARING, Contact::FRIEND])) {
 622                         return true;
 623                 }
 624
 625                 // When the possible receiver isn't a community, then it is no valid receiver
 626                 $owner = User::getOwnerDataById($contact['uid']);
 627                 if (empty($owner) || ($owner['contact-type'] != Contact::TYPE_COMMUNITY)) {
 628                         return false;
 629                 }
 630
 631                 // Is the community account tagged?
 632                 foreach ($tags as $tag) {
 633                         if ($tag['type'] != 'Mention') {
 634                                 continue;
 635                         }
 636
 637                         if ($tag['href'] == $owner['url']) {
 638                                 return true;
 639                         }
 640                 }
 641
 642                 return false;
 643         }
 644
 645         /**
 646          * Switches existing contacts to ActivityPub
 647          *
 648          * @param integer $cid Contact ID
 649          * @param integer $uid User ID
 650          * @param string  $url Profile URL
 651          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 652          * @throws \ImagickException
 653          */
 654         public static function switchContact($cid, $uid, $url)
 655         {
 656                 $profile = ActivityPub::probeProfile($url);
 657                 if (empty($profile)) {
 658                         return;
 659                 }
 660
 661                 Logger::log('Switch contact ' . $cid . ' (' . $profile['url'] . ') for user ' . $uid . ' to ActivityPub');
 662
 663                 $photo = defaults($profile, 'photo', null);
 664                 unset($profile['photo']);
 665                 unset($profile['baseurl']);
 666                 unset($profile['guid']);
 667
 668                 $profile['nurl'] = Strings::normaliseLink($profile['url']);
 669                 DBA::update('contact', $profile, ['id' => $cid]);
 670
 671                 Contact::updateAvatar($photo, $uid, $cid);
 672
 673                 // Send a new follow request to be sure that the connection still exists
 674                 if (($uid != 0) && DBA::exists('contact', ['id' => $cid, 'rel' => [Contact::SHARING, Contact::FRIEND]])) {
 675                         ActivityPub\Transmitter::sendActivity('Follow', $profile['url'], $uid);
 676                         Logger::log('Send a new follow request to ' . $profile['url'] . ' for user ' . $uid, Logger::DEBUG);
 677                 }
 678         }
 679
 680         /**
 681          *
 682          *
 683          * @param $receivers
 684          * @param $actor
 685          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 686          * @throws \ImagickException
 687          */
 688         private static function switchContacts($receivers, $actor)
 689         {
 690                 if (empty($actor)) {
 691                         return;
 692                 }
 693
 694                 foreach ($receivers as $receiver) {
 695                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver, 'network' => Protocol::OSTATUS, 'nurl' => Strings::normaliseLink($actor)]);
 696                         if (DBA::isResult($contact)) {
 697                                 self::switchContact($contact['id'], $receiver, $actor);
 698                         }
 699
 700                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver, 'network' => Protocol::OSTATUS, 'alias' => [Strings::normaliseLink($actor), $actor]]);
 701                         if (DBA::isResult($contact)) {
 702                                 self::switchContact($contact['id'], $receiver, $actor);
 703                         }
 704                 }
 705         }
 706
 707         /**
 708          *
 709          *
 710          * @param       $object_data
 711          * @param array $activity
 712          *
 713          * @return mixed
 714          */
 715         private static function addActivityFields($object_data, $activity)
 716         {
 717                 if (!empty($activity['published']) && empty($object_data['published'])) {
 718                         $object_data['published'] = JsonLD::fetchElement($activity, 'as:published', '@value');
 719                 }
 720
 721                 if (!empty($activity['diaspora:guid']) && empty($object_data['diaspora:guid'])) {
 722                         $object_data['diaspora:guid'] = JsonLD::fetchElement($activity, 'diaspora:guid', '@value');
 723                 }
 724
 725                 $object_data['service'] = JsonLD::fetchElement($activity, 'as:instrument', 'as:name', '@type', 'as:Service');
 726                 $object_data['service'] = JsonLD::fetchElement($object_data, 'service', '@value');
 727
 728                 return $object_data;
 729         }
 730
 731         /**
 732          * Fetches the object data from external ressources if needed
 733          *
 734          * @param string  $object_id    Object ID of the the provided object
 735          * @param array   $object       The provided object array
 736          * @param boolean $trust_source Do we trust the provided object?
 737          * @param integer $uid          User ID for the signature that we use to fetch data
 738          *
 739          * @return array with trusted and valid object data
 740          * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 741          * @throws \ImagickException
 742          */
 743         private static function fetchObject($object_id, $object = [], $trust_source = false, $uid = 0)
 744         {
 745                 // By fetching the type we check if the object is complete.
 746                 $type = JsonLD::fetchElement($object, '@type');
 747
 748                 if (!$trust_source || empty($type)) {
 749                         $data = ActivityPub::fetchContent($object_id, $uid);
 750                         if (!empty($data)) {
 751                                 $object = JsonLD::compact($data);
 752                                 Logger::log('Fetched content for ' . $object_id, Logger::DEBUG);
 753                         } else {
 754                                 Logger::log('Empty content for ' . $object_id . ', check if content is available locally.', Logger::DEBUG);
 755
 756                                 $item = Item::selectFirst([], ['uri' => $object_id]);
 757                                 if (!DBA::isResult($item)) {
 758                                         Logger::log('Object with url ' . $object_id . ' was not found locally.', Logger::DEBUG);
 759                                         return false;
 760                                 }
 761                                 Logger::log('Using already stored item for url ' . $object_id, Logger::DEBUG);
 762                                 $data = ActivityPub\Transmitter::createNote($item);
 763                                 $object = JsonLD::compact($data);
 764                         }
 765                 } else {
 766                         Logger::log('Using original object for url ' . $object_id, Logger::DEBUG);
 767                 }
 768
 769                 $type = JsonLD::fetchElement($object, '@type');
 770
 771                 if (empty($type)) {
 772                         Logger::log('Empty type', Logger::DEBUG);
 773                         return false;
 774                 }
 775
 776                 if (in_array($type, self::CONTENT_TYPES)) {
 777                         return self::processObject($object);
 778                 }
 779
 780                 if ($type == 'as:Announce') {
 781                         $object_id = JsonLD::fetchElement($object, 'object', '@id');
 782                         if (empty($object_id)) {
 783                                 return false;
 784                         }
 785                         return self::fetchObject($object_id, [], false, $uid);
 786                 }
 787
 788                 Logger::log('Unhandled object type: ' . $type, Logger::DEBUG);
 789         }
 790
 791         /**
 792          * Convert tags from JSON-LD format into a simplified format
 793          *
 794          * @param array $tags Tags in JSON-LD format
 795          *
 796          * @return array with tags in a simplified format
 797          */
 798         private static function processTags($tags)
 799         {
 800                 $taglist = [];
 801
 802                 if (empty($tags)) {
 803                         return [];
 804                 }
 805
 806                 foreach ($tags as $tag) {
 807                         if (empty($tag)) {
 808                                 continue;
 809                         }
 810
 811                         $element = ['type' => str_replace('as:', '', JsonLD::fetchElement($tag, '@type')),
 812                                 'href' => JsonLD::fetchElement($tag, 'as:href', '@id'),
 813                                 'name' => JsonLD::fetchElement($tag, 'as:name', '@value')];
 814
 815                         if (empty($element['type'])) {
 816                                 continue;
 817                         }
 818
 819                         $taglist[] = $element;
 820                 }
 821                 return $taglist;
 822         }
 823
 824         /**
 825          * Convert emojis from JSON-LD format into a simplified format
 826          *
 827          * @param $emojis
 828          * @return array with emojis in a simplified format
 829          */
 830         private static function processEmojis($emojis)
 831         {
 832                 $emojilist = [];
 833
 834                 if (empty($emojis)) {
 835                         return [];
 836                 }
 837
 838                 foreach ($emojis as $emoji) {
 839                         if (empty($emoji) || (JsonLD::fetchElement($emoji, '@type') != 'toot:Emoji') || empty($emoji['as:icon'])) {
 840                                 continue;
 841                         }
 842
 843                         $url = JsonLD::fetchElement($emoji['as:icon'], 'as:url', '@id');
 844                         $element = ['name' => JsonLD::fetchElement($emoji, 'as:name', '@value'),
 845                                 'href' => $url];
 846
 847                         $emojilist[] = $element;
 848                 }
 849                 return $emojilist;
 850         }
 851
 852         /**
 853          * Convert attachments from JSON-LD format into a simplified format
 854          *
 855          * @param array $attachments Attachments in JSON-LD format
 856          *
 857          * @return array with attachmants in a simplified format
 858          */
 859         private static function processAttachments($attachments)
 860         {
 861                 $attachlist = [];
 862
 863                 if (empty($attachments)) {
 864                         return [];
 865                 }
 866
 867                 foreach ($attachments as $attachment) {
 868                         if (empty($attachment)) {
 869                                 continue;
 870                         }
 871
 872                         $attachlist[] = ['type' => str_replace('as:', '', JsonLD::fetchElement($attachment, '@type')),
 873                                 'mediaType' => JsonLD::fetchElement($attachment, 'as:mediaType', '@value'),
 874                                 'name' => JsonLD::fetchElement($attachment, 'as:name', '@value'),
 875                                 'url' => JsonLD::fetchElement($attachment, 'as:url', '@id')];
 876                 }
 877                 return $attachlist;
 878         }
 879
 880         /**
 881          * Fetches data from the object part of an activity
 882          *
 883          * @param array $object
 884          *
 885          * @return array
 886          * @throws \Exception
 887          */
 888         private static function processObject($object)
 889         {
 890                 if (!JsonLD::fetchElement($object, '@id')) {
 891                         return false;
 892                 }
 893
 894                 $object_data = [];
 895                 $object_data['object_type'] = JsonLD::fetchElement($object, '@type');
 896                 $object_data['id'] = JsonLD::fetchElement($object, '@id');
 897                 $object_data['reply-to-id'] = JsonLD::fetchElement($object, 'as:inReplyTo', '@id');
 898
 899                 // An empty "id" field is translated to "./" by the compactor, so we have to check for this content
 900                 if (empty($object_data['reply-to-id']) || ($object_data['reply-to-id'] == './')) {
 901                         $object_data['reply-to-id'] = $object_data['id'];
 902                 }
 903
 904                 $object_data['published'] = JsonLD::fetchElement($object, 'as:published', '@value');
 905                 $object_data['updated'] = JsonLD::fetchElement($object, 'as:updated', '@value');
 906
 907                 if (empty($object_data['updated'])) {
 908                         $object_data['updated'] = $object_data['published'];
 909                 }
 910
 911                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
 912                         $object_data['published'] = $object_data['updated'];
 913                 }
 914
 915                 $actor = JsonLD::fetchElement($object, 'as:attributedTo', '@id');
 916                 if (empty($actor)) {
 917                         $actor = JsonLD::fetchElement($object, 'as:actor', '@id');
 918                 }
 919
 920                 $object_data['diaspora:guid'] = JsonLD::fetchElement($object, 'diaspora:guid', '@value');
 921                 $object_data['diaspora:comment'] = JsonLD::fetchElement($object, 'diaspora:comment', '@value');
 922                 $object_data['diaspora:like'] = JsonLD::fetchElement($object, 'diaspora:like', '@value');
 923                 $object_data['actor'] = $object_data['author'] = $actor;
 924                 $object_data['context'] = JsonLD::fetchElement($object, 'as:context', '@id');
 925                 $object_data['conversation'] = JsonLD::fetchElement($object, 'ostatus:conversation', '@id');
 926                 $object_data['sensitive'] = JsonLD::fetchElement($object, 'as:sensitive');
 927                 $object_data['name'] = JsonLD::fetchElement($object, 'as:name', '@value');
 928                 $object_data['summary'] = JsonLD::fetchElement($object, 'as:summary', '@value');
 929                 $object_data['content'] = JsonLD::fetchElement($object, 'as:content', '@value');
 930                 $object_data['source'] = JsonLD::fetchElement($object, 'as:source', 'as:content', 'as:mediaType', 'text/bbcode');
 931                 $object_data['source'] = JsonLD::fetchElement($object_data, 'source', '@value');
 932                 $object_data['start-time'] = JsonLD::fetchElement($object, 'as:startTime', '@value');
 933                 $object_data['end-time'] = JsonLD::fetchElement($object, 'as:endTime', '@value');
 934                 $object_data['location'] = JsonLD::fetchElement($object, 'as:location', 'as:name', '@type', 'as:Place');
 935                 $object_data['location'] = JsonLD::fetchElement($object_data, 'location', '@value');
 936                 $object_data['latitude'] = JsonLD::fetchElement($object, 'as:location', 'as:latitude', '@type', 'as:Place');
 937                 $object_data['latitude'] = JsonLD::fetchElement($object_data, 'latitude', '@value');
 938                 $object_data['longitude'] = JsonLD::fetchElement($object, 'as:location', 'as:longitude', '@type', 'as:Place');
 939                 $object_data['longitude'] = JsonLD::fetchElement($object_data, 'longitude', '@value');
 940                 $object_data['attachments'] = self::processAttachments(JsonLD::fetchElementArray($object, 'as:attachment'));
 941                 $object_data['tags'] = self::processTags(JsonLD::fetchElementArray($object, 'as:tag'));
 942                 $object_data['emojis'] = self::processEmojis(JsonLD::fetchElementArray($object, 'as:tag', 'toot:Emoji'));
 943                 $object_data['generator'] = JsonLD::fetchElement($object, 'as:generator', 'as:name', '@type', 'as:Application');
 944                 $object_data['generator'] = JsonLD::fetchElement($object_data, 'generator', '@value');
 945                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'as:url', '@id');
 946
 947                 // Special treatment for Hubzilla links
 948                 if (is_array($object_data['alternate-url'])) {
 949                         $object_data['alternate-url'] = JsonLD::fetchElement($object_data['alternate-url'], 'as:href', '@id');
 950
 951                         if (!is_string($object_data['alternate-url'])) {
 952                                 $object_data['alternate-url'] = JsonLD::fetchElement($object['as:url'], 'as:href', '@id');
 953                         }
 954                 }
 955
 956                 $object_data['receiver'] = self::getReceivers($object, $object_data['actor'], $object_data['tags']);
 957
 958                 // Common object data:
 959
 960                 // Unhandled
 961                 // @context, type, actor, signature, mediaType, duration, replies, icon
 962
 963                 // Also missing: (Defined in the standard, but currently unused)
 964                 // audience, preview, endTime, startTime, image
 965
 966                 // Data in Notes:
 967
 968                 // Unhandled
 969                 // contentMap, announcement_count, announcements, context_id, likes, like_count
 970                 // inReplyToStatusId, shares, quoteUrl, statusnetConversationId
 971
 972                 // Data in video:
 973
 974                 // To-Do?
 975                 // category, licence, language, commentsEnabled
 976
 977                 // Unhandled
 978                 // views, waitTranscoding, state, support, subtitleLanguage
 979                 // likes, dislikes, shares, comments
 980
 981                 return $object_data;
 982         }
 983 }