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\Util\HTTPSignature;
   9 use Friendica\Core\Protocol;
  10 use Friendica\Model\Contact;
  11 use Friendica\Model\APContact;
  12 use Friendica\Model\Item;
  13 use Friendica\Model\User;
  14 use Friendica\Util\JsonLD;
  15 use Friendica\Util\LDSignature;
  16 use Friendica\Protocol\ActivityPub;
  17
  18 /**
  19  * @brief ActivityPub Receiver Protocol class
  20  *
  21  * To-Do:
  22  * - Update (Image, Video, Article, Note)
  23  * - Event
  24  * - Undo Announce
  25  *
  26  * Check what this is meant to do:
  27  * - Add
  28  * - Block
  29  * - Flag
  30  * - Remove
  31  * - Undo Block
  32  * - Undo Accept (Problem: This could invert a contact accept or an event accept)
  33  *
  34  * General:
  35  * - Possibly using the LD-JSON parser
  36  */
  37 class Receiver
  38 {
  39         /**
  40          * Checks if the web request is done for the AP protocol
  41          *
  42          * @return is it AP?
  43          */
  44         public static function isRequest()
  45         {
  46                 return stristr(defaults($_SERVER, 'HTTP_ACCEPT', ''), 'application/activity+json') ||
  47                         stristr(defaults($_SERVER, 'HTTP_ACCEPT', ''), 'application/ld+json');
  48         }
  49
  50         /**
  51          *
  52          *
  53          * @param $body
  54          * @param $header
  55          * @param integer $uid User ID
  56          */
  57         public static function processInbox($body, $header, $uid)
  58         {
  59                 $http_signer = HTTPSignature::getSigner($body, $header);
  60                 if (empty($http_signer)) {
  61                         logger('Invalid HTTP signature, message will be discarded.', LOGGER_DEBUG);
  62                         return;
  63                 } else {
  64                         logger('HTTP signature is signed by ' . $http_signer, LOGGER_DEBUG);
  65                 }
  66
  67                 $activity = json_decode($body, true);
  68
  69                 $actor = JsonLD::fetchElement($activity, 'actor', 'id');
  70                 logger('Message for user ' . $uid . ' is from actor ' . $actor, LOGGER_DEBUG);
  71
  72                 if (empty($activity)) {
  73                         logger('Invalid body.', LOGGER_DEBUG);
  74                         return;
  75                 }
  76
  77                 if (LDSignature::isSigned($activity)) {
  78                         $ld_signer = LDSignature::getSigner($activity);
  79                         if (empty($ld_signer)) {
  80                                 logger('Invalid JSON-LD signature from ' . $actor, LOGGER_DEBUG);
  81                         }
  82                         if (!empty($ld_signer && ($actor == $http_signer))) {
  83                                 logger('The HTTP and the JSON-LD signature belong to ' . $ld_signer, LOGGER_DEBUG);
  84                                 $trust_source = true;
  85                         } elseif (!empty($ld_signer)) {
  86                                 logger('JSON-LD signature is signed by ' . $ld_signer, LOGGER_DEBUG);
  87                                 $trust_source = true;
  88                         } elseif ($actor == $http_signer) {
  89                                 logger('Bad JSON-LD signature, but HTTP signer fits the actor.', LOGGER_DEBUG);
  90                                 $trust_source = true;
  91                         } else {
  92                                 logger('Invalid JSON-LD signature and the HTTP signer is different.', LOGGER_DEBUG);
  93                                 $trust_source = false;
  94                         }
  95                 } elseif ($actor == $http_signer) {
  96                         logger('Trusting post without JSON-LD signature, The actor fits the HTTP signer.', LOGGER_DEBUG);
  97                         $trust_source = true;
  98                 } else {
  99                         logger('No JSON-LD signature, different actor.', LOGGER_DEBUG);
 100                         $trust_source = false;
 101                 }
 102
 103                 self::processActivity($activity, $body, $uid, $trust_source);
 104         }
 105
 106         /**
 107          *
 108          *
 109          * @param array $activity
 110          * @param integer $uid User ID
 111          * @param $trust_source
 112          *
 113          * @return
 114          */
 115         private static function prepareObjectData($activity, $uid, &$trust_source)
 116         {
 117                 $actor = JsonLD::fetchElement($activity, 'actor', 'id');
 118                 if (empty($actor)) {
 119                         logger('Empty actor', LOGGER_DEBUG);
 120                         return [];
 121                 }
 122
 123                 // Fetch all receivers from to, cc, bto and bcc
 124                 $receivers = self::getReceivers($activity, $actor);
 125
 126                 // When it is a delivery to a personal inbox we add that user to the receivers
 127                 if (!empty($uid)) {
 128                         $owner = User::getOwnerDataById($uid);
 129                         $additional = ['uid:' . $uid => $uid];
 130                         $receivers = array_merge($receivers, $additional);
 131                 }
 132
 133                 logger('Receivers: ' . json_encode($receivers), LOGGER_DEBUG);
 134
 135                 $object_id = JsonLD::fetchElement($activity, 'object', 'id');
 136                 if (empty($object_id)) {
 137                         logger('No object found', LOGGER_DEBUG);
 138                         return [];
 139                 }
 140
 141                 // Fetch the content only on activities where this matters
 142                 if (in_array($activity['type'], ['Create', 'Announce'])) {
 143                         $object_data = self::fetchObject($object_id, $activity['object'], $trust_source);
 144                         if (empty($object_data)) {
 145                                 logger("Object data couldn't be processed", LOGGER_DEBUG);
 146                                 return [];
 147                         }
 148                         // We had been able to retrieve the object data - so we can trust the source
 149                         $trust_source = true;
 150                 } elseif (in_array($activity['type'], ['Like', 'Dislike'])) {
 151                         // Create a mostly empty array out of the activity data (instead of the object).
 152                         // This way we later don't have to check for the existence of ech individual array element.
 153                         $object_data = self::processObject($activity);
 154                         $object_data['name'] = $activity['type'];
 155                         $object_data['author'] = $activity['actor'];
 156                         $object_data['object'] = $object_id;
 157                         $object_data['object_type'] = ''; // Since we don't fetch the object, we don't know the type
 158                 } else {
 159                         $object_data = [];
 160                         $object_data['id'] = $activity['id'];
 161                         $object_data['object'] = $activity['object'];
 162                         $object_data['object_type'] = JsonLD::fetchElement($activity, 'object', 'type');
 163                 }
 164
 165                 $object_data = self::addActivityFields($object_data, $activity);
 166
 167                 $object_data['type'] = $activity['type'];
 168                 $object_data['owner'] = $actor;
 169                 $object_data['receiver'] = array_merge(defaults($object_data, 'receiver', []), $receivers);
 170
 171                 logger('Processing ' . $object_data['type'] . ' ' . $object_data['object_type'] . ' ' . $object_data['id'], LOGGER_DEBUG);
 172
 173                 return $object_data;
 174         }
 175
 176         /**
 177          *
 178          *
 179          * @param array $activity
 180          * @param $body
 181          * @param integer $uid User ID
 182          * @param $trust_source
 183          */
 184         public static function processActivity($activity, $body = '', $uid = null, $trust_source = false)
 185         {
 186                 if (empty($activity['type'])) {
 187                         logger('Empty type', LOGGER_DEBUG);
 188                         return;
 189                 }
 190
 191                 if (empty($activity['object'])) {
 192                         logger('Empty object', LOGGER_DEBUG);
 193                         return;
 194                 }
 195
 196                 if (empty($activity['actor'])) {
 197                         logger('Empty actor', LOGGER_DEBUG);
 198                         return;
 199
 200                 }
 201
 202                 // $trust_source is called by reference and is set to true if the content was retrieved successfully
 203                 $object_data = self::prepareObjectData($activity, $uid, $trust_source);
 204                 if (empty($object_data)) {
 205                         logger('No object data found', LOGGER_DEBUG);
 206                         return;
 207                 }
 208
 209                 if (!$trust_source) {
 210                         logger('No trust for activity type "' . $activity['type'] . '", so we quit now.', LOGGER_DEBUG);
 211                         return;
 212                 }
 213
 214                 switch ($activity['type']) {
 215                         case 'Create':
 216                         case 'Announce':
 217                                 ActivityPub\Processor::createItem($object_data, $body);
 218                                 break;
 219
 220                         case 'Like':
 221                                 ActivityPub\Processor::likeItem($object_data, $body);
 222                                 break;
 223
 224                         case 'Dislike':
 225                                 ActivityPub\Processor::dislikeItem($object_data, $body);
 226                                 break;
 227
 228                         case 'Update':
 229                                 if (in_array($object_data['object_type'], ActivityPub::CONTENT_TYPES)) {
 230                                         /// @todo
 231                                 } elseif (in_array($object_data['object_type'], ActivityPub::ACCOUNT_TYPES)) {
 232                                         ActivityPub\Processor::updatePerson($object_data, $body);
 233                                 }
 234                                 break;
 235
 236                         case 'Delete':
 237                                 if ($object_data['object_type'] == 'Tombstone') {
 238                                         ActivityPub\Processor::deleteItem($object_data, $body);
 239                                 } elseif (in_array($object_data['object_type'], ActivityPub::ACCOUNT_TYPES)) {
 240                                         ActivityPub\Processor::deletePerson($object_data, $body);
 241                                 }
 242                                 break;
 243
 244                         case 'Follow':
 245                                 ActivityPub\Processor::followUser($object_data);
 246                                 break;
 247
 248                         case 'Accept':
 249                                 if ($object_data['object_type'] == 'Follow') {
 250                                         ActivityPub\Processor::acceptFollowUser($object_data);
 251                                 }
 252                                 break;
 253
 254                         case 'Reject':
 255                                 if ($object_data['object_type'] == 'Follow') {
 256                                         ActivityPub\Processor::rejectFollowUser($object_data);
 257                                 }
 258                                 break;
 259
 260                         case 'Undo':
 261                                 if ($object_data['object_type'] == 'Follow') {
 262                                         ActivityPub\Processor::undoFollowUser($object_data);
 263                                 } elseif (in_array($object_data['object_type'], ActivityPub::ACTIVITY_TYPES)) {
 264                                         ActivityPub\Processor::undoActivity($object_data);
 265                                 }
 266                                 break;
 267
 268                         default:
 269                                 logger('Unknown activity: ' . $activity['type'], LOGGER_DEBUG);
 270                                 break;
 271                 }
 272         }
 273
 274         /**
 275          *
 276          *
 277          * @param array $activity
 278          * @param $actor
 279          *
 280          * @return
 281          */
 282         private static function getReceivers($activity, $actor)
 283         {
 284                 $receivers = [];
 285
 286                 // When it is an answer, we inherite the receivers from the parent
 287                 $replyto = JsonLD::fetchElement($activity, 'inReplyTo', 'id');
 288                 if (!empty($replyto)) {
 289                         $parents = Item::select(['uid'], ['uri' => $replyto]);
 290                         while ($parent = Item::fetch($parents)) {
 291                                 $receivers['uid:' . $parent['uid']] = $parent['uid'];
 292                         }
 293                 }
 294
 295                 if (!empty($actor)) {
 296                         $profile = APContact::getByURL($actor);
 297                         $followers = defaults($profile, 'followers', '');
 298
 299                         logger('Actor: ' . $actor . ' - Followers: ' . $followers, LOGGER_DEBUG);
 300                 } else {
 301                         logger('Empty actor', LOGGER_DEBUG);
 302                         $followers = '';
 303                 }
 304
 305                 foreach (['to', 'cc', 'bto', 'bcc'] as $element) {
 306                         if (empty($activity[$element])) {
 307                                 continue;
 308                         }
 309
 310                         // The receiver can be an array or a string
 311                         if (is_string($activity[$element])) {
 312                                 $activity[$element] = [$activity[$element]];
 313                         }
 314
 315                         foreach ($activity[$element] as $receiver) {
 316                                 if ($receiver == ActivityPub::PUBLIC_COLLECTION) {
 317                                         $receivers['uid:0'] = 0;
 318                                 }
 319
 320                                 if (($receiver == ActivityPub::PUBLIC_COLLECTION) && !empty($actor)) {
 321                                         // This will most likely catch all OStatus connections to Mastodon
 322                                         $condition = ['alias' => [$actor, normalise_link($actor)], 'rel' => [Contact::SHARING, Contact::FRIEND]
 323                                                 , 'archive' => false, 'pending' => false];
 324                                         $contacts = DBA::select('contact', ['uid'], $condition);
 325                                         while ($contact = DBA::fetch($contacts)) {
 326                                                 if ($contact['uid'] != 0) {
 327                                                         $receivers['uid:' . $contact['uid']] = $contact['uid'];
 328                                                 }
 329                                         }
 330                                         DBA::close($contacts);
 331                                 }
 332
 333                                 if (in_array($receiver, [$followers, ActivityPub::PUBLIC_COLLECTION]) && !empty($actor)) {
 334                                         $condition = ['nurl' => normalise_link($actor), 'rel' => [Contact::SHARING, Contact::FRIEND],
 335                                                 'network' => Protocol::ACTIVITYPUB, 'archive' => false, 'pending' => false];
 336                                         $contacts = DBA::select('contact', ['uid'], $condition);
 337                                         while ($contact = DBA::fetch($contacts)) {
 338                                                 if ($contact['uid'] != 0) {
 339                                                         $receivers['uid:' . $contact['uid']] = $contact['uid'];
 340                                                 }
 341                                         }
 342                                         DBA::close($contacts);
 343                                         continue;
 344                                 }
 345
 346                                 $condition = ['self' => true, 'nurl' => normalise_link($receiver)];
 347                                 $contact = DBA::selectFirst('contact', ['uid'], $condition);
 348                                 if (!DBA::isResult($contact)) {
 349                                         continue;
 350                                 }
 351                                 $receivers['uid:' . $contact['uid']] = $contact['uid'];
 352                         }
 353                 }
 354
 355                 self::switchContacts($receivers, $actor);
 356
 357                 return $receivers;
 358         }
 359
 360         /**
 361          * Switches existing contacts to ActivityPub
 362          *
 363          * @param integer $cid Contact ID
 364          * @param integer $uid User ID
 365          * @param string $url Profile URL
 366          */
 367         private static function switchContact($cid, $uid, $url)
 368         {
 369                 $profile = ActivityPub::probeProfile($url);
 370                 if (empty($profile)) {
 371                         return;
 372                 }
 373
 374                 logger('Switch contact ' . $cid . ' (' . $profile['url'] . ') for user ' . $uid . ' to ActivityPub');
 375
 376                 $photo = $profile['photo'];
 377                 unset($profile['photo']);
 378                 unset($profile['baseurl']);
 379
 380                 $profile['nurl'] = normalise_link($profile['url']);
 381                 DBA::update('contact', $profile, ['id' => $cid]);
 382
 383                 Contact::updateAvatar($photo, $uid, $cid);
 384
 385                 // Send a new follow request to be sure that the connection still exists
 386                 if (($uid != 0) && DBA::exists('contact', ['id' => $cid, 'rel' => [Contact::SHARING, Contact::FRIEND]])) {
 387                         ActivityPub\Transmitter::sendActivity('Follow', $profile['url'], $uid);
 388                         logger('Send a new follow request to ' . $profile['url'] . ' for user ' . $uid, LOGGER_DEBUG);
 389                 }
 390         }
 391
 392         /**
 393          *
 394          *
 395          * @param $receivers
 396          * @param $actor
 397          */
 398         private static function switchContacts($receivers, $actor)
 399         {
 400                 if (empty($actor)) {
 401                         return;
 402                 }
 403
 404                 foreach ($receivers as $receiver) {
 405                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver, 'network' => Protocol::OSTATUS, 'nurl' => normalise_link($actor)]);
 406                         if (DBA::isResult($contact)) {
 407                                 self::switchContact($contact['id'], $receiver, $actor);
 408                         }
 409
 410                         $contact = DBA::selectFirst('contact', ['id'], ['uid' => $receiver, 'network' => Protocol::OSTATUS, 'alias' => [normalise_link($actor), $actor]]);
 411                         if (DBA::isResult($contact)) {
 412                                 self::switchContact($contact['id'], $receiver, $actor);
 413                         }
 414                 }
 415         }
 416
 417         /**
 418          *
 419          *
 420          * @param $object_data
 421          * @param array $activity
 422          *
 423          * @return
 424          */
 425         private static function addActivityFields($object_data, $activity)
 426         {
 427                 if (!empty($activity['published']) && empty($object_data['published'])) {
 428                         $object_data['published'] = $activity['published'];
 429                 }
 430
 431                 if (!empty($activity['updated']) && empty($object_data['updated'])) {
 432                         $object_data['updated'] = $activity['updated'];
 433                 }
 434
 435                 if (!empty($activity['inReplyTo']) && empty($object_data['parent-uri'])) {
 436                         $object_data['parent-uri'] = JsonLD::fetchElement($activity, 'inReplyTo', 'id');
 437                 }
 438
 439                 if (!empty($activity['instrument'])) {
 440                         $object_data['service'] = JsonLD::fetchElement($activity, 'instrument', 'name', 'type', 'Service');
 441                 }
 442                 return $object_data;
 443         }
 444
 445         /**
 446          *
 447          *
 448          * @param $object_id
 449          * @param $object
 450          * @param $trust_source
 451          *
 452          * @return
 453          */
 454         private static function fetchObject($object_id, $object = [], $trust_source = false)
 455         {
 456                 if (!$trust_source || is_string($object)) {
 457                         $data = ActivityPub::fetchContent($object_id);
 458                         if (empty($data)) {
 459                                 logger('Empty content for ' . $object_id . ', check if content is available locally.', LOGGER_DEBUG);
 460                                 $data = $object_id;
 461                         } else {
 462                                 logger('Fetched content for ' . $object_id, LOGGER_DEBUG);
 463                         }
 464                 } else {
 465                         logger('Using original object for url ' . $object_id, LOGGER_DEBUG);
 466                         $data = $object;
 467                 }
 468
 469                 if (is_string($data)) {
 470                         $item = Item::selectFirst([], ['uri' => $data]);
 471                         if (!DBA::isResult($item)) {
 472                                 logger('Object with url ' . $data . ' was not found locally.', LOGGER_DEBUG);
 473                                 return false;
 474                         }
 475                         logger('Using already stored item for url ' . $object_id, LOGGER_DEBUG);
 476                         $data = ActivityPub\Transmitter::createNote($item);
 477                 }
 478
 479                 if (empty($data['type'])) {
 480                         logger('Empty type', LOGGER_DEBUG);
 481                         return false;
 482                 }
 483
 484                 if (in_array($data['type'], ActivityPub::CONTENT_TYPES)) {
 485                         return self::processObject($data);
 486                 }
 487
 488                 if ($data['type'] == 'Announce') {
 489                         if (empty($data['object'])) {
 490                                 return false;
 491                         }
 492                         return self::fetchObject($data['object']);
 493                 }
 494
 495                 logger('Unhandled object type: ' . $data['type'], LOGGER_DEBUG);
 496         }
 497
 498         /**
 499          *
 500          *
 501          * @param $object
 502          *
 503          * @return
 504          */
 505         private static function processObject($object)
 506         {
 507                 if (empty($object['id'])) {
 508                         return false;
 509                 }
 510
 511                 $object_data = [];
 512                 $object_data['object_type'] = $object['type'];
 513                 $object_data['id'] = $object['id'];
 514
 515                 if (!empty($object['inReplyTo'])) {
 516                         $object_data['reply-to-id'] = JsonLD::fetchElement($object, 'inReplyTo', 'id');
 517                 } else {
 518                         $object_data['reply-to-id'] = $object_data['id'];
 519                 }
 520
 521                 $object_data['published'] = defaults($object, 'published', null);
 522                 $object_data['updated'] = defaults($object, 'updated', $object_data['published']);
 523
 524                 if (empty($object_data['published']) && !empty($object_data['updated'])) {
 525                         $object_data['published'] = $object_data['updated'];
 526                 }
 527
 528                 $actor = JsonLD::fetchElement($object, 'attributedTo', 'id');
 529                 if (empty($actor)) {
 530                         $actor = defaults($object, 'actor', null);
 531                 }
 532
 533                 $object_data['diaspora:guid'] = defaults($object, 'diaspora:guid', null);
 534                 $object_data['owner'] = $object_data['author'] = $actor;
 535                 $object_data['context'] = defaults($object, 'context', null);
 536                 $object_data['conversation'] = defaults($object, 'conversation', null);
 537                 $object_data['sensitive'] = defaults($object, 'sensitive', null);
 538                 $object_data['name'] = defaults($object, 'title', null);
 539                 $object_data['name'] = defaults($object, 'name', $object_data['name']);
 540                 $object_data['summary'] = defaults($object, 'summary', null);
 541                 $object_data['content'] = defaults($object, 'content', null);
 542                 $object_data['source'] = defaults($object, 'source', null);
 543                 $object_data['location'] = JsonLD::fetchElement($object, 'location', 'name', 'type', 'Place');
 544                 $object_data['attachments'] = defaults($object, 'attachment', null);
 545                 $object_data['tags'] = defaults($object, 'tag', null);
 546                 $object_data['service'] = JsonLD::fetchElement($object, 'instrument', 'name', 'type', 'Service');
 547                 $object_data['alternate-url'] = JsonLD::fetchElement($object, 'url', 'href');
 548                 $object_data['receiver'] = self::getReceivers($object, $object_data['owner']);
 549
 550                 // Common object data:
 551
 552                 // Unhandled
 553                 // @context, type, actor, signature, mediaType, duration, replies, icon
 554
 555                 // Also missing: (Defined in the standard, but currently unused)
 556                 // audience, preview, endTime, startTime, generator, image
 557
 558                 // Data in Notes:
 559
 560                 // Unhandled
 561                 // contentMap, announcement_count, announcements, context_id, likes, like_count
 562                 // inReplyToStatusId, shares, quoteUrl, statusnetConversationId
 563
 564                 // Data in video:
 565
 566                 // To-Do?
 567                 // category, licence, language, commentsEnabled
 568
 569                 // Unhandled
 570                 // views, waitTranscoding, state, support, subtitleLanguage
 571                 // likes, dislikes, shares, comments
 572
 573                 return $object_data;
 574         }
 575 }